{
  "spore": "profile",
  "id": "stainless-440c",
  "spore_version": "0.2",
  "family": "stainless-martensitic",
  "name": "Stainless steel 440C",
  "abbreviation": "440C (UNS S44004)",
  "role": "high-carbon martensitic stainless steel for bearings and valve parts",
  "category": "metals",
  "type": "steels-and-stainless",
  "summary": "440C is the highest-carbon 400-series stainless steel, a martensitic iron alloy with 0.95 to 1.20 percent carbon and 16 to 18 percent chromium. Heat-treated, it reaches about HRC 60, the highest hardness of any stainless steel in these sources, and its hardness depends on the temper. It is used mainly for ball and roller bearings and valve parts.",
  "best_for": "Bearings and valve parts that must be hard and wear-resistant in the hardened and tempered condition (Carpenter, Aalco, Rolled Alloys)",
  "weakest_at": "Corrosion resistance in the annealed state or after tempering above about 800 F (427 C), and service above about 400 C (NASA 2018 maximum use temperature)",
  "identity": {
    "formula": "Fe balance, 0.95 to 1.20 C, 16.0 to 18.0 Cr, 0.75 max Mo (Rolled Alloys and Carpenter; EN 10088-3 gives 0.40 to 0.80 Mo), 1.00 max Mn, 1.00 max Si, 0.04 max P, 0.03 max S (wt%)",
    "designations": [
      {
        "system": "UNS",
        "code": "S44004",
        "source": "rolled-440c",
        "where": "Specifications line (UNS: S44004); also UNS #S44004 on the Carpenter page"
      },
      {
        "system": "EN",
        "code": "1.4125",
        "source": "rolled-440c",
        "where": "Specifications line (W. Nr./EN: 1.4125); also 1.4125 in the Aalco datasheet title"
      },
      {
        "system": "JIS",
        "code": "SUS440C",
        "source": "patent-jp6207408",
        "where": "Background text: SUS440C (C: specified in JIS G4303 as martensitic stainless steel)"
      },
      {
        "system": "JIS",
        "code": "G4303",
        "source": "patent-jp6207408",
        "where": "Same background sentence; JIS G4303 cited as the standard for martensitic grades"
      },
      {
        "system": "ASTM",
        "code": "A 276",
        "source": "rolled-440c",
        "where": "Specifications line (ASTM: A 276); printed as ASTM A276 on the Carpenter page and in the Aircraft Materials specification list"
      },
      {
        "system": "AMS",
        "code": "5630",
        "source": "rolled-440c",
        "where": "Specifications line (AMS: 5630, 5880)"
      },
      {
        "system": "AMS",
        "code": "5880",
        "source": "rolled-440c",
        "where": "Specifications line (AMS: 5630, 5880)"
      },
      {
        "system": "AISI",
        "code": "440C",
        "source": "aircraft-materials-440c",
        "where": "Title line (Alloy 440C / AISI 440C / AMS 5630)"
      }
    ],
    "source": "rolled-440c",
    "where": "Chemical composition table, Min and Max columns (Rolled Alloys bulletin 1142); EN 10088-3 Mo range from the Aalco datasheet"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "mechanisms",
      "propulsion-and-tanks"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "value": 0.275,
      "bound": "exact",
      "unit": "lb/in3",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table as printed (Density: 0.275 lb/in3); the bulletin gives no SI value",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Physical Properties table (Density row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "value": 7.65,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "standard": "EN 10088-3:2005 bar",
        "temperature": "not stated",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table as printed (Density 7.65 g/cm3)",
      "status": "ground",
      "source": "aalco-440c-bar",
      "where": "Physical Properties table (Density row)",
      "source_detail": {
        "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
        "id": "EN 10088-3:2005 bar",
        "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "value": 7.7,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, 440C column, printed as 7.7 g/cc",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table, first table (Density row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "value": 200,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table as printed (Modulus of Elasticity 200 GPa)",
      "status": "ground",
      "source": "aalco-440c-bar",
      "where": "Physical Properties table (Modulus of Elasticity row)",
      "source_detail": {
        "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
        "id": "EN 10088-3:2005 bar",
        "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "value": 200,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not printed on the datasheet"
      },
      "method": "UPMET datasheet, Physical Properties table, printed as 200 GPa",
      "status": "ground",
      "source": "upmet-440c",
      "where": "Physical Properties table (Elastic Modulus row)",
      "source_detail": {
        "title": "United Performance Metals: Alloy 440C datasheet (AMS 5630 chemistry)",
        "id": "ALLOY 440C",
        "url": "https://www.upmet.com/sites/default/files/datasheets/440c.pdf",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "value": 200,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, printed as 200 GPa (Young's Modulus row)",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Young's Modulus row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "value": 30.4,
      "bound": "exact",
      "unit": "psi x 10^6",
      "scope": "material",
      "conditions": {
        "temperature": "70 F",
        "heat_treatment": "not stated",
        "basis": "dynamic modulus, as printed"
      },
      "method": "Physical properties table, Modulus of Elasticity, Dynamic, printed as 30.4 psi x 10^6 at 70 F; dynamic, not the static value",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Physical Properties table (Modulus of Elasticity, Dynamic row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "value": 0.3,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, printed as 0.3 for 440C",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Poisson's ratio row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 24.2,
      "bound": "exact",
      "unit": "W/m.K",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Physical properties table as printed (Thermal Conductivity 24.2 W/m.K)",
      "status": "ground",
      "source": "aalco-440c-bar",
      "where": "Physical Properties table (Thermal Conductivity row)",
      "source_detail": {
        "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
        "id": "EN 10088-3:2005 bar",
        "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 24,
      "bound": "exact",
      "unit": "W/m-°K",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, printed as 24 W/m-°K for 440C",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Thermal conductivity row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "value": 13.2,
      "bound": "exact",
      "unit": "Btu·ft/ft2·hr·°F",
      "scope": "material",
      "conditions": {
        "temperature": "70 F",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table at 70 F, printed as 13.2 Btu ft/ft2 hr F (unit printed with bullets)",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Physical Properties table (Thermal Conductivity row, temperature column 70)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "value": 10.1,
      "bound": "exact",
      "unit": "10-6/K",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "unit_in_source": "x10^-6 /K"
      },
      "method": "Physical properties table as printed (Thermal Expansion 10.1 x10^-6 /K); same unit written in short form",
      "status": "ground",
      "source": "aalco-440c-bar",
      "where": "Physical Properties table (Thermal Expansion row)",
      "source_detail": {
        "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
        "id": "EN 10088-3:2005 bar",
        "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "value": 10,
      "bound": "exact",
      "unit": "10-6/°C",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, printed as 10x10^-6/°C for 440C",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Thermal expansion row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "cte",
      "value": 5.6,
      "bound": "exact",
      "unit": "in/in°F x 10^-6",
      "scope": "material",
      "conditions": {
        "temperature": "70 F to the indicated temperature (table column at 70 F)",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table, coefficient marked with footnote: 70 F to indicated temperature; printed in inches per inch per F",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Physical Properties table (Coefficient of Thermal Expansion row and footnote)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 2500,
      "value_high": 2700,
      "bound": "range",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "temperature": "melting range as printed",
        "heat_treatment": "not stated"
      },
      "method": "Physical properties table as printed (Melting Range 2500 - 2700 F)",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Physical Properties table (Melting Range row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "value": 0.6,
      "bound": "exact",
      "unit": "10-6 ohm.m",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "unit_in_source": "x10^-6 Ω.m"
      },
      "method": "Physical properties table as printed (Electrical Resistivity 0.6 x10^-6 Ω.m)",
      "status": "ground",
      "source": "aalco-440c-bar",
      "where": "Physical Properties table (Electrical Resistivity row)",
      "source_detail": {
        "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
        "id": "EN 10088-3:2005 bar",
        "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "value": 0.6,
      "bound": "exact",
      "unit": "10-6 ohm.m",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "heat_treatment": "not stated on the slide",
        "basis": "approximate, printed with a tilde"
      },
      "method": "NASA Glenn 2018 comparison table, first table, printed as ~0.60x10^-6 Ω-m for 440C",
      "status": "ground",
      "note": "The second 440C table on the same slide prints about 36 x10^-6 Ω-cm, which conflicts; the first table is used.",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table, first table (Electrical resistivity row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "value": 400,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "maximum use temperature, printed as about 400 C (approximate)",
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, Maximum use temp row, printed as ~400 °C for 440C",
      "status": "ground",
      "note": "Printed with a tilde (about 400 C); the slide does not give the basis or the temper.",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Maximum use temp row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "fracture_toughness",
      "value": 22,
      "bound": "exact",
      "unit": "MPa/√m",
      "scope": "material",
      "conditions": {
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, printed as 22 MPa/√m for 440C (Fracture toughness row); benchmark name is not in property-canon.yaml",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Fracture toughness row)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 300 F",
      "value": 60,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 300 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (300 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 400 F",
      "value": 59,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 400 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (400 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 500 F",
      "value": 57,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 500 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (500 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 600 F",
      "value": 56,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 600 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (600 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 700 F",
      "value": 56,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 700 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (700 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Rockwell C after a one-hour temper at 800 F",
      "value": 56,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered one hour at 800 F",
        "specimen": "1 in round"
      },
      "method": "Typical Hardness table, Rockwell C row, as printed",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Typical Hardness table (800 F column)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Annealed hardness (approximate)",
      "value": 223,
      "bound": "exact",
      "unit": "HB",
      "scope": "material",
      "conditions": {
        "heat_treatment": "annealed: heat to 1550 to 1600 F, slow cool in the furnace"
      },
      "method": "Annealing paragraph, printed as Brinell hardness should be approximately 223",
      "status": "ground",
      "note": "Approximate value, as printed.",
      "source": "rolled-440c",
      "where": "Annealing paragraph",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Brinell hardness at the 600 F temper",
      "value": 580,
      "bound": "exact",
      "unit": "HB",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "test_temperature": "not printed"
      },
      "method": "Typical Mechanical Properties table, Brinell Hardness column, as printed",
      "status": "ground",
      "source": "aircraft-materials-440c",
      "where": "Typical Mechanical Properties table (Alloy 440C row, Brinell Hardness)",
      "source_detail": {
        "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet (Alloy 440C, AISI 440C, AMS 5630)",
        "id": "Alloy 440C page",
        "url": "https://www.aircraftmaterials.com/data/alstst/440c.html",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "hardness",
      "label": "As heat treated, before any tempering",
      "value": 60,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "heat treated to HRC 60 per the HPOTP bearing procedure, not tempered in this row",
        "specimen": "AISI 440C rods 7.9 mm diameter"
      },
      "method": "Tempering section, text: as-heat-treated material (HRC 60)",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Tempering Behavior and Hot Hardness section (Specimens; Figure 14 text)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "After tempering at 540 C for 10 to 945 s, from HRC 60",
      "value": 57,
      "value_high": 58,
      "bound": "range",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "from HRC 60, tempered at 540 C (1000 F) for 10 to 945 s",
        "temperature": "540 C (1000 F)",
        "time": "10, 105 and 945 s"
      },
      "method": "Short-term tempering results, printed as reduced the hardness from the initial value of HRC 60 to HRC 57-58",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Short-Term Tempering Behavior, Results",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "After tempering at 650 C for 105 s, from HRC 60",
      "value": 50.5,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "from HRC 60, tempered at 650 C (1200 F) for 105 s",
        "temperature": "650 C (1200 F)",
        "time": "105 s"
      },
      "method": "Results text, printed as the hardness was reduced to HRC 50.5 at 105 seconds",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Short-Term Tempering Behavior, Results (text after Figure 12)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "After tempering at 650 C for 420 s, from HRC 60",
      "value": 46.5,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "from HRC 60, tempered at 650 C (1200 F) for 420 s",
        "temperature": "650 C (1200 F)",
        "time": "420 s"
      },
      "method": "Results text, printed as the hardness was reduced to HRC 46.5 at 420 seconds",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Short-Term Tempering Behavior, Results (text after Figure 12)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "After tempering at 760 C for 10 s, from HRC 60",
      "value": 44,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "from HRC 60, tempered at 760 C (1400 F) for 10 s",
        "temperature": "760 C (1400 F)",
        "time": "10 s"
      },
      "method": "Results text, printed as the hardness was reduced to HRC 44 in 10 seconds at 760 C",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Short-Term Tempering Behavior, Results (text after Figure 12)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "After tempering at 760 C for 105 s, from HRC 60",
      "value": 40,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "from HRC 60, tempered at 760 C (1400 F) for 105 s",
        "temperature": "760 C (1400 F)",
        "time": "105 s"
      },
      "method": "Results text, printed as HRC 40 in 105 seconds at 760 C",
      "status": "ground",
      "note": "The Figure 14 caption prints HRC 58 for 760 C at 105 s; the text value of HRC 40 is used.",
      "source": "nasa-1984-ntrs",
      "where": "Short-Term Tempering Behavior, Results (text after Figure 12)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hot hardness at 540 C, used HPOTP race",
      "value": 30,
      "bound": "upper",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "temperature": "540 C (1000 F)",
        "specimen": "cut from a used HPOTP bearing race that measured HRC 50 at room temperature",
        "test": "hot-hardness apparatus; diamond pyramid hardness numbers converted in the text"
      },
      "method": "Hot-Hardness Measurements section, printed as less than DPHN 300 (HRC 30) at 540 C (1000 F)",
      "status": "ground",
      "source": "nasa-1984-ntrs",
      "where": "Hot-Hardness Measurements section (Figure 15 discussion)",
      "source_detail": {
        "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
        "id": "NTRS 19840014892 (report dated 2 April 1984)",
        "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
        "year": 1984,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hardness range as compared by NASA Glenn",
      "value": 58,
      "value_high": 62,
      "bound": "range",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "heat_treatment": "not stated on the slide"
      },
      "method": "NASA Glenn 2018 comparison table, Hardness row, printed as 58 to 62 HRC for 440C",
      "status": "ground",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Hardness row, 440C column)",
      "source_detail": {
        "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
        "id": "NTRS 20180002168",
        "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
        "year": 2018,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "value": 1965,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "test_temperature": "not printed"
      },
      "method": "Typical Mechanical Properties table, Ultimate Tensile Strength column (MPa), as printed",
      "status": "ground",
      "source": "aircraft-materials-440c",
      "where": "Typical Mechanical Properties table (Alloy 440C row, Ultimate Tensile Strength column)",
      "source_detail": {
        "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet (Alloy 440C, AISI 440C, AMS 5630)",
        "id": "Alloy 440C page",
        "url": "https://www.aircraftmaterials.com/data/alstst/440c.html",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "value": 285,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "temperature": "70 F"
      },
      "method": "Representative Tensile Properties table, Ultimate Tensile Strength row, printed as 285 ksi",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Mechanical Properties table (Representative Tensile Properties, Ultimate Tensile Strength row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "yield_strength",
      "value": 1896,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "test_temperature": "not printed",
        "basis": "0.2 percent offset yield, as printed"
      },
      "method": "Typical Mechanical Properties table, Yield Strength 0.2% (MPa) column, as printed",
      "status": "ground",
      "source": "aircraft-materials-440c",
      "where": "Typical Mechanical Properties table (Yield Strength column)",
      "source_detail": {
        "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet (Alloy 440C, AISI 440C, AMS 5630)",
        "id": "Alloy 440C page",
        "url": "https://www.aircraftmaterials.com/data/alstst/440c.html",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "yield_strength",
      "value": 275,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "temperature": "70 F",
        "basis": "0.2 percent offset yield, as printed"
      },
      "method": "Representative Tensile Properties table, 0.2% Yield Strength row, printed as 275 ksi",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Mechanical Properties table (0.2% Yield Strength row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "gauge": "2 in, as printed in the Elongation column"
      },
      "method": "Typical Mechanical Properties table, Elongation column, as printed",
      "status": "ground",
      "source": "aircraft-materials-440c",
      "where": "Typical Mechanical Properties table (Elongation column)",
      "source_detail": {
        "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet (Alloy 440C, AISI 440C, AMS 5630)",
        "id": "Alloy 440C page",
        "url": "https://www.aircraftmaterials.com/data/alstst/440c.html",
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "heat_treatment": "hardened 1900 F, oil quench, tempered 600 F",
        "temperature": "70 F"
      },
      "method": "Representative Tensile Properties table, Elongation row, printed as 2 %",
      "status": "ground",
      "source": "rolled-440c",
      "where": "Mechanical Properties table (Elongation row)",
      "source_detail": {
        "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
        "id": "Bulletin No. 1142",
        "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Atmosphere, fresh water, foods, alkalies and mild acids",
      "headline": "Good general resistance, best when hardened, tempered and passivated.",
      "effect": "Aalco: good resistance to the atmosphere, fresh water, foods, alkalies and mild acids, with the best resistance in the hardened, tempered and passivated condition. A smooth polished surface also helps.",
      "rating": "low",
      "conditions": {
        "best_case": "hardened, tempered and passivated, polished"
      },
      "source": "aalco-440c-bar",
      "where": "Corrosion Resistance section"
    },
    {
      "environment": "Compared with the common austenitic grades",
      "headline": "Lower corrosion resistance than the common austenitic grades.",
      "effect": "Aalco: corrosion resistance is lower than the common austenitic grades, and the useful temperature range is limited by loss of ductility below zero and loss of strength by over-tempering at elevated temperatures.",
      "rating": "moderate",
      "source": "aalco-440c-bar",
      "where": "Martensitic stainless steels paragraph"
    },
    {
      "environment": "Many environments, compared with 304",
      "headline": "About the same as 304 in many environments.",
      "effect": "Aalco: the corrosion resistance of 440C approximates that of 304 in many environments.",
      "rating": "low",
      "source": "aalco-440c-bar",
      "where": "Corrosion Resistance section"
    },
    {
      "environment": "Annealed condition, or hardened and tempered above about 800 F (427 C)",
      "headline": "Corrosion resistance is reduced when annealed or tempered above 800 F.",
      "effect": "Carpenter: 440C is not usually recommended for elevated temperature applications, since corrosion resistance is reduced when used in the annealed condition or hardened and tempered above about 800 F (427 C).",
      "rating": "moderate",
      "conditions": {
        "temperature": "above about 800 F (427 C) temper, or annealed"
      },
      "source": "carpenter-440c",
      "where": "Product description paragraph"
    },
    {
      "environment": "Tempering between 425 and 565 C",
      "headline": "Avoid this tempering range.",
      "effect": "Aalco: tempering in the range 425 to 565 C is to be avoided because of reduced impact resistance and corrosion resistance.",
      "rating": "moderate",
      "conditions": {
        "temperature": "425 to 565 C tempering"
      },
      "source": "aalco-440c-bar",
      "where": "Heat Treatment section"
    },
    {
      "environment": "General corrosion, rated Marginal by NASA",
      "headline": "NASA rates 440C corrosion resistance Marginal, and hard steels rust.",
      "effect": "NASA Glenn's 2018 comparison rates the corrosion resistance of 440C as Marginal, against Excellent for 60NiTi in aqueous and acidic service, and says hard steels are prone to rusting, even stainless steels like 440C.",
      "rating": "moderate",
      "source": "nasa-2018-ntrs",
      "where": "Technical Properties Comparison table (Corrosion resistance row); Materials Requirements slide"
    },
    {
      "environment": "Overheating during grinding",
      "headline": "Grinding heat lowers hardness and corrosion resistance.",
      "effect": "Rolled Alloys: do not overheat while grinding, since both the hardness and corrosion resistance may be lowered.",
      "rating": "moderate",
      "source": "rolled-440c",
      "where": "Grinding and Polishing section"
    },
    {
      "environment": "Above the tempering temperature",
      "headline": "Not recommended above the tempering temperature, because of over-tempering.",
      "effect": "Aalco: not recommended for use in temperatures above the relevant tempering temperature, because mechanical properties are reduced by over-tempering.",
      "rating": "unknown",
      "source": "aalco-440c-bar",
      "where": "Heat Resistance section"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "In a NIOSH-authored study of stainless steel welding fume, the hexavalent chromium fraction ranged from 2800 to 34,000 ppm across eight welding process and shielding-gas combinations, and generation rates ranged from 69 to 7800 ug/min.",
        "ghs": [],
        "source": "pmc-cr6-welding",
        "where": "Abstract (Cr6+ fraction and generation rate results)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Ball wear in unlubricated sliding contact",
        "trigger": "440C in self-mated sliding contact without lubrication (liquid-nitrogen test rig)",
        "consequence": "Wear rates were high enough to explain the ball wear sometimes seen in HPOTP bearings.",
        "severity": "high",
        "source": "nasa-1984-ntrs",
        "where": "Summary"
      },
      {
        "mode": "Softening from heat",
        "trigger": "Bulk bearing temperatures of 480 C (900 F) or more, or extended time at 540 C (1000 F)",
        "consequence": "NASA 1984: hot hardness falls rapidly at 540 C (1000 F) and above, and at 760 C (1400 F) hardness fell from HRC 60 to HRC 44 in 10 s and HRC 40 in 105 s.",
        "severity": "high",
        "source": "nasa-1984-ntrs",
        "where": "Summary; Hot-Hardness Measurements section; Results text"
      },
      {
        "mode": "Over-tempering",
        "trigger": "Service or tempering above the tempering temperature",
        "consequence": "Aalco: mechanical properties are reduced by over-tempering at elevated temperatures, so use above the tempering temperature is not recommended.",
        "severity": "moderate",
        "source": "aalco-440c-bar",
        "where": "Martensitic stainless steels paragraph; Heat Resistance section"
      },
      {
        "mode": "Rusting in moist or wet service",
        "trigger": "Moisture or wet service",
        "consequence": "NASA Glenn says hard steels are prone to rusting, even stainless steels such as 440C.",
        "severity": "moderate",
        "source": "nasa-2018-ntrs",
        "where": "Materials Requirements slide (Technical Challenge list)"
      },
      {
        "mode": "Soft or hard welds from the wrong filler",
        "trigger": "Choice of welding filler (Aalco lists 420, 309 and 310 fillers)",
        "consequence": "Aalco: a grade 420 filler gives a high-hardness weld, while 309 or 310 gives soft welds with higher ductility.",
        "severity": "moderate",
        "source": "aalco-440c-bar",
        "where": "Weldability section"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Machine in the annealed condition; once hardened, machining becomes much harder and probably impossible (Aalco). Chips are tough and stringy, so chip breakers matter (Aalco, Rolled Alloys).",
        "source": "aalco-440c-bar",
        "where": "Machinability section"
      },
      {
        "text": "Do not overheat when grinding, since hardness and corrosion resistance can be lowered (Rolled Alloys).",
        "source": "rolled-440c",
        "where": "Grinding and Polishing section"
      },
      {
        "text": "Hardening: heat to 1010 to 1065 C, then quench in warm oil or air, with oil for heavy sections (Aalco).",
        "source": "aalco-440c-bar",
        "where": "Heat Treatment section (Hardening)"
      },
      {
        "text": "Hardening: heat to 1850 to 1950 F, quench in warm oil or air, and temper immediately between 300 and 800 F, depending on the hardness wanted (Rolled Alloys).",
        "source": "rolled-440c",
        "where": "Hardening section"
      },
      {
        "text": "Weldability: if welding is needed, preheat to about 250 C and follow with a full anneal (Aalco).",
        "source": "aalco-440c-bar",
        "where": "Weldability section"
      },
      {
        "text": "Weldability: Rolled Alloys preheats to about 500 F, welds, then anneals at 1350 to 1400 F for 6 to 8 hours, cooling slowly in the furnace.",
        "source": "rolled-440c",
        "where": "Weldability section"
      }
    ],
    "mitigations": [
      {
        "text": "Keep the temper at or below about 800 F (427 C) where corrosion resistance matters (Carpenter).",
        "source": "carpenter-440c",
        "where": "Product description paragraph"
      },
      {
        "text": "Avoid tempering between 425 and 565 C, the range that lowers impact and corrosion resistance; 590 to 675 C gives lower hardness and high impact resistance (Aalco).",
        "source": "aalco-440c-bar",
        "where": "Heat Treatment section"
      },
      {
        "text": "Short overheats are tolerable: tempering times of 10 seconds or less can be taken up to 650 C (1200 F) without significant hardness loss (NASA 1984).",
        "source": "nasa-1984-ntrs",
        "where": "Summary"
      },
      {
        "text": "Weld with 309 or 310 filler when soft, ductile welds are wanted, since 420 gives a high-hardness weld (Aalco).",
        "source": "aalco-440c-bar",
        "where": "Weldability section"
      }
    ]
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Rolling-element bearings (ball and roller)",
      "example": "Carpenter says 440C has been used primarily as a bearing steel, in the hardened plus tempered condition.",
      "source": "carpenter-440c",
      "where": "Product description paragraph"
    },
    {
      "application": "mechanisms",
      "device": "Valve seats and valve parts",
      "example": "Aalco lists valve seats and says 440C is particularly suited to ball bearings and valve parts; UPMET lists ball bearings and valves.",
      "source": "aalco-440c-bar",
      "where": "Applications list (Valve seats)"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "High-pressure oxygen turbopump bearings of the Space Shuttle main engine (HPOTP)",
      "example": "NASA's 1984 Battelle report measured 440C wear and tempering for these bearings and found that unlubricated 440C wear could explain the ball wear seen in service.",
      "source": "nasa-1984-ntrs",
      "where": "Introduction and Summary"
    },
    {
      "application": "mechanisms",
      "device": "Bearing races in spacecraft reaction-wheel assemblies (NASA comparison)",
      "example": "NASA Glenn's 2018 slides compare 440C with 60NiTi and credit 60NiTi bearing races with 2x (against Rex 20) to 5x (against 440C) improvement in a reaction-wheel bearing.",
      "source": "nasa-2018-ntrs",
      "where": "Space Bearing Application slide (Typical Reaction Wheel Assembly)"
    }
  ],
  "supply": [
    {
      "subject": "Chromium",
      "abundance": "World mine production about 51,000 thousand metric tons, gross weight, in 2025 (estimated). World resources are greater than 12 billion tons of shipping-grade chromite, 95 percent in Kazakhstan and southern Africa (USGS 2026).",
      "producers": [
        {
          "country": "South Africa",
          "share_percent": 45.1,
          "year": 2025
        },
        {
          "country": "Turkey",
          "share_percent": 17.6,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 13.7,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 5.9,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 3.9,
          "year": 2025
        },
        {
          "country": "Zimbabwe",
          "share_percent": 3.9,
          "year": 2025
        },
        {
          "country": "Finland",
          "share_percent": 3.7,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "Recycled chromium in reported stainless-steel scrap receipts was 21 percent of US apparent consumption in 2025 (USGS 2026).",
      "substitutes": [
        "Chromium has no substitute in stainless steel, the leading end use, or in superalloys (USGS 2026)"
      ],
      "source": "usgs-chromium-2026",
      "where": "World Mine Production and Reserves table (2025e, gross weight; shares computed from the printed tonnage); World Resources; Substitutes; Recycling"
    },
    {
      "subject": "Chromium import reliance (United States)",
      "abundance": "US net import reliance was 79 percent of apparent consumption in 2025 (estimated). Chromite imports for 2021 to 2024 came from South Africa (96 percent) and Turkey (3 percent).",
      "producers": [],
      "critical_lists": [],
      "recycling": "Recycled chromium was 21 percent of US apparent consumption in 2025.",
      "substitutes": [],
      "source": "usgs-chromium-2026",
      "where": "Salient Statistics (Net import reliance row); Import Sources (2021-24)"
    },
    {
      "subject": "Molybdenum",
      "abundance": "World mine production 260,000 t of molybdenum content in 2025 (estimated). Identified resources are about 5.4 million tons in the United States and about 20 million tons in the rest of the world (USGS 2026).",
      "producers": [
        {
          "country": "China",
          "share_percent": 37.3,
          "year": 2025
        },
        {
          "country": "Chile",
          "share_percent": 16.2,
          "year": 2025
        },
        {
          "country": "United States",
          "share_percent": 15.4,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 15,
          "year": 2025
        },
        {
          "country": "Mexico",
          "share_percent": 6.5,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "Molybdenum recycled from steel, superalloy and catalyst scrap may be as much as 30 percent of apparent supply (USGS 2026).",
      "substitutes": [
        "Little substitution in its main use in steels and cast irons; potential substitutes in alloy steels include boron, chromium, niobium and vanadium (USGS 2026)"
      ],
      "source": "usgs-molybdenum-2026",
      "where": "World Mine Production and Reserves table (2025e, molybdenum content; shares computed from the printed tonnage); Substitutes; Recycling"
    },
    {
      "subject": "Molybdenum trade and policy",
      "abundance": "The United States is a net exporter of molybdenum (USGS 2026), with 40,000 t of molybdenum content mine production in 2025 (estimated). China imposed export controls on molybdenum powders in February 2025.",
      "producers": [],
      "critical_lists": [],
      "recycling": "",
      "substitutes": [],
      "source": "usgs-molybdenum-2026",
      "where": "Salient Statistics (Net import reliance row, E = net exporter); Events, Trends, and Issues"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142)",
      "type": "datasheet",
      "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
      "year": 2015
    },
    {
      "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet",
      "type": "datasheet",
      "url": "https://www.aircraftmaterials.com/data/alstst/440c.html"
    },
    {
      "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar datasheet (EN 10088-3:2005)",
      "type": "datasheet",
      "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx"
    },
    {
      "title": "United Performance Metals: Alloy 440C datasheet",
      "type": "datasheet",
      "url": "https://www.upmet.com/sites/default/files/datasheets/440c.pdf"
    },
    {
      "title": "Carpenter Technology: 440C alloy page",
      "type": "datasheet",
      "url": "https://www.carpentertechnology.com/alloy-finder/440c"
    },
    {
      "title": "NASA Glenn (DellaCorte, 2018): Ni-Ti Next Generation Bearings for Space Applications",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
      "year": 2018
    },
    {
      "title": "Battelle for NASA (Dufrane et al., 1984): Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
      "year": 1984
    },
    {
      "title": "Effects of Heat Treatment on the Properties of SS440C for Blades Applications (Springer Proceedings in Physics 289; UniMAP repository copy)",
      "type": "paper",
      "url": "https://ris.unimap.edu.my/entities/publication/1eddb8c2-050b-427f-8b49-0de618f67a03"
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Chromium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Molybdenum",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf",
      "year": 2026
    },
    {
      "title": "Keane et al. (NIOSH): Selecting Processes to Minimize Hexavalent Chromium from Stainless Steel Welding",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC4681305"
    },
    {
      "title": "Google Patents JP6207408B2 (background text naming SUS440C and JIS G4303)",
      "type": "paper",
      "url": "https://patents.google.com/patent/JP6207408B2/en"
    }
  ],
  "gaps": [
    "ASTM A582 is not printed by any fetched 440C source (Rolled Alloys, Carpenter, Aalco, Aircraft Materials, UPMET, NASA 2018), so it is not in designations. Aalco names 440F (UNS S44020) as a free-machining variant, which is a different grade.",
    "The JIS standard itself was not reached. SUS440C and JIS G4303 come from the background text of Japanese patent JP6207408B2. The Nachi-Fujikoshi SUS440C table returned a 404 error.",
    "No tensile, yield or elongation value for annealed 440C was taken from a fetched source. Wikipedia's annealed row was not used, because the brief limits Wikipedia to composition and history.",
    "No tensile or yield values across the 300 to 800 F temper range were found. The only 600 F strength values are representative values from two datasheets (Rolled Alloys and Aircraft Materials), and no strength temper curve was read.",
    "Aalco's EN 10088-3 ranges (proof stress 448 to 1900 MPa, tensile 758 to 2030 MPa, elongation 4 to 14 %) span several tempers, so they are not used as single values.",
    "UPMET's 440C datasheet prints yield 448 MPa, tensile 75 MPa (probably a typo), elongation 14 % and hardness 269 HB max with no heat-treatment condition, so none are used. Its density (7650 kg/cm3) has a unit slip, and its thermal conductivity (24.2 at 212 F) and electrical resistivity (600) have no unit.",
    "The Carpenter 440C page gives composition, specifications and uses only, with no property values.",
    "The UniMAP copy of the Springer paper prints an as-received annealed hardness of 11.4 HRC, which does not fit the other annealed data (Rolled Alloys: about 223 HB), so it is not used. Its tensile results are not given as numbers in the abstract.",
    "The NASA 2018 slides give 440C electrical resistivity as about 0.60 x10^-6 ohm.m in one table and about 36 x10^-6 ohm.cm in the other; only the first is used. Its 1900 MPa tensile value has no temper, so it is not used.",
    "No specific heat value was read from any fetched 440C source.",
    "No 440C safety data sheet was reached. The PubChem chromium and molybdenum records fetched in this run carry no hazard codes in their text, so they are not cited. OSHA (403), DOL (blocked) and CDC stacks (access denied) could not be read. The hazard source is a NIOSH-authored study of stainless steel welding fume, not a 440C study.",
    "No source for dust or fume from grinding or machining 440C was read.",
    "USGS critical-mineral list status for chromium and molybdenum was not checked (the MCS chapters do not print the lists), so critical_lists is empty.",
    "Supply shares are computed by hand from printed tonnage (basis given per producer); they are not printed percentages.",
    "No ESA or ECSS source for 440C was found. The space links come from two NASA reports only: a Space Shuttle main engine turbopump bearing study (1984) and a 2018 reaction-wheel bearing comparison.",
    "hardness and fracture_toughness are not in property-canon.yaml, so short names are used for them.",
    "Not usable in this run: Starrapid 440C PDF (download failed), ASM Alloy Digest SS-101 (no text), Hudson Tool Steel 440C page (no text), AZoM 440C bar page (supplier list, no property values), SB Specialty Metals 440C data sheet (no values in text).",
    "No cryogenic tensile data and no high-temperature tensile data for 440C were found beyond the 1984 hardness tests."
  ],
  "story": {
    "why": "440C is a high-carbon martensitic stainless steel built for hardness. It is hardened by heat treatment, and Carpenter says it is used in the hardened plus tempered condition. Its main use is bearings and valve parts, and NASA studied 440C bearings in the Space Shuttle main engine's high-pressure oxygen turbopump. The trade-off is corrosion resistance: Carpenter says it falls in the annealed state and after tempering above about 800 F (427 C), and NASA's 2018 comparison rates it marginal.",
    "uses": [
      {
        "where": "Bearings and valve parts",
        "line": "Rolled Alloys, Aalco and UPMET all list bearings and valve parts (UPMET: ball bearings and valves). Aalco also lists high-quality knife blades, surgical instruments and chisels."
      },
      {
        "where": "Space Shuttle main engine turbopump bearings",
        "line": "A 1984 NASA report on the high-pressure oxygen turbopump bearings measured 440C wear and tempering. It found that wear in unlubricated contact could explain the ball wear seen in service."
      },
      {
        "where": "Space reaction-wheel bearing comparison (2018)",
        "line": "NASA Glenn's 2018 slides compare 440C with 60NiTi for space bearings. They credit 60NiTi bearing races with 2x (against Rex 20) to 5x (against 440C) improvement in a reaction-wheel bearing."
      }
    ],
    "can_do": [
      {
        "label": "Hardness",
        "line": "Hardened and tempered, 440C reaches about HRC 60, the highest hardness of any stainless steel (Carpenter, Rolled Alloys). The temper sets it: 60 HRC after a one-hour temper at 300 F, and 56 HRC after tempering at 600 to 800 F (Rolled Alloys).",
        "scope": "material"
      },
      {
        "label": "Strength",
        "line": "At the 600 F temper, Aircraft Materials gives 1965 MPa tensile and 1896 MPa yield, and Rolled Alloys gives 285 ksi and 275 ksi for the same heat treatment, with 2 percent elongation.",
        "scope": "material"
      },
      {
        "label": "Stiffness",
        "line": "Young's modulus is 200 GPa in the Aalco, UPMET and NASA 2018 records.",
        "scope": "material"
      },
      {
        "label": "Heat tolerance",
        "line": "In NASA's 1984 tests, tempering at 540 C (1000 F) for 10 to 945 s dropped hardness from HRC 60 only to HRC 57 to 58. Bulk bearing temperatures of 480 C (900 F) or more could not be tolerated in the turbopump bearings.",
        "scope": "material"
      },
      {
        "label": "Service temperature",
        "line": "NASA Glenn gives about 400 C as the maximum use temperature of 440C in its 2018 comparison.",
        "scope": "material"
      }
    ],
    "compare": "Against common stainless steels, 440C trades corrosion resistance for hardness. Aalco says its corrosion resistance approximates that of 304 in many environments, and that martensitic grades resist corrosion less than the common austenitic grades. NASA's 2018 comparison rates 440C corrosion resistance as marginal and calls the austenitic 304 soft, while it lists 60NiTi, a superelastic bearing alloy, as excellent in aqueous and acidic service.",
    "compare_rows": [
      {
        "label": "Tensile strength at the 600 F temper",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting range",
        "benchmark": "melting_point",
        "scope": "material"
      }
    ],
    "handling": [
      "Machine in the annealed condition. Once hardened, machining becomes much harder and probably impossible (Aalco).",
      "Do not overheat when grinding, since hardness and corrosion resistance can fall (Rolled Alloys).",
      "Temper straight after quenching, at the temperature that gives the hardness you need (Rolled Alloys, Aalco).",
      "Welding is seldom needed. If it is, preheat (about 250 C, or 500 F) and anneal afterwards (Aalco, Rolled Alloys)."
    ],
    "good_for": [
      "Bearings, where hardness and wear resistance matter (Carpenter, Aalco, Rolled Alloys).",
      "Valve seats and valve parts (Aalco, Rolled Alloys, UPMET).",
      "Knife blades, surgical instruments and chisels (Aalco, UPMET)."
    ],
    "watch_out": [
      "Corrosion. NASA rates it marginal, and Aalco says it is less corrosion resistant than the common austenitic grades.",
      "Tempering between 425 and 565 C, which reduces impact and corrosion resistance (Aalco).",
      "Long holds at 540 C (1000 F), or bulk temperatures of 480 C (900 F) and above, which take bearing hardness to unusable levels (NASA 1984).",
      "Welding, which is seldom done. Filler choice changes the weld hardness (Aalco, Rolled Alloys)."
    ],
    "verdict": "Of the stainless steels in these sources, 440C is the hardest when heat-treated, so it is the bearing and valve choice when hardness matters most. Accept its marginal corrosion resistance, keep the temper at or below about 800 F (427 C), and keep service below about 400 C.",
    "recipe": {
      "line": "440C is an iron-based martensitic stainless steel. Carbon (0.95 to 1.20 percent) is the highest of the 400 series, and chromium (16 to 18 percent) gives the stainless film. Rolled Alloys, Carpenter and Aalco print the same carbon and chromium limits, and Wikipedia gives the same ranges. Molybdenum is 0.75 percent maximum in Rolled Alloys and Carpenter, while EN 10088-3 (Aalco) allows 0.40 to 0.80 percent. The record gives limits, not a single analysis.",
      "parts": [
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "The matrix. As a martensitic stainless steel it can be hardened by heat treatment (Rolled Alloys).",
          "share_note": "balance (the rest)",
          "source": "rolled-440c",
          "where": "Chemical composition table (Fe balance)"
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Gives the high hardness; Rolled Alloys calls 440C the highest carbon content of the 400 series stainless steels.",
          "share_percent": 0.95,
          "share_high": 1.2,
          "source": "rolled-440c",
          "where": "Chemical composition table (C, min 0.95, max 1.2); Features list"
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "Keeps the stainless characteristics despite the high carbon (Rolled Alloys).",
          "share_percent": 16,
          "share_high": 18,
          "source": "rolled-440c",
          "where": "Chemical composition table (Cr, min 16.0, max 18.0)"
        },
        {
          "name": "Molybdenum",
          "symbol": "Mo",
          "role": "Maximum 0.75 (Rolled Alloys and Carpenter); EN 10088-3 allows 0.40 to 0.80 (Aalco).",
          "share_percent": 0,
          "share_high": 0.75,
          "source": "rolled-440c",
          "where": "Chemical composition table (Mo, max 0.75)"
        },
        {
          "name": "Manganese",
          "symbol": "Mn",
          "role": "Residual element, held to a maximum.",
          "share_percent": 0,
          "share_high": 1,
          "source": "rolled-440c",
          "where": "Chemical composition table (Mn, max 1.00)"
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Residual element, held to a maximum.",
          "share_percent": 0,
          "share_high": 1,
          "source": "rolled-440c",
          "where": "Chemical composition table (Si, max 1.00)"
        },
        {
          "name": "Phosphorus",
          "symbol": "P",
          "role": "Impurity held to a maximum.",
          "share_percent": 0,
          "share_high": 0.04,
          "source": "rolled-440c",
          "where": "Chemical composition table (P, max 0.04)"
        },
        {
          "name": "Sulfur",
          "symbol": "S",
          "role": "Impurity held to a maximum.",
          "share_percent": 0,
          "share_high": 0.03,
          "source": "rolled-440c",
          "where": "Chemical composition table (S, max 0.03)"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet for 440C was reached. The hazard source found is a NIOSH-authored study of stainless steel welding fume.",
        "points": [
          {
            "label": "Welding fume",
            "line": "In the NIOSH-authored study, the hexavalent chromium fraction of stainless steel welding fume ranged from 2800 to 34,000 ppm across eight process and shielding-gas combinations."
          },
          {
            "label": "Scope",
            "line": "The study covers welding fume in general, not 440C alone, so treat it as a guide until a 440C safety data sheet is checked."
          }
        ],
        "level": 1,
        "verdict": "Welding fume is the main human-health watch point"
      },
      {
        "title": "In service",
        "lead": "NASA's 1984 study of turbopump bearings found that 440C softens with heat and wears fast when unlubricated.",
        "points": [
          {
            "label": "Heat",
            "line": "Bulk bearing temperatures of 480 C (900 F) or more could not be tolerated, and hot hardness falls rapidly from 540 C (1000 F)."
          },
          {
            "label": "Wear",
            "line": "Unlubricated 440C wear rates were high enough to explain the ball wear seen in service."
          }
        ],
        "level": 2,
        "verdict": "Heat and poor lubrication are the failure routes"
      },
      {
        "title": "Corrosion and temper",
        "lead": "Corrosion resistance is best in the hardened, tempered and passivated condition (Aalco).",
        "points": [
          {
            "label": "Avoid",
            "line": "Tempering between 425 and 565 C reduces impact and corrosion resistance (Aalco)."
          },
          {
            "label": "Above 800 F",
            "line": "Hardened and tempered above about 800 F (427 C), or annealed, the corrosion resistance is reduced (Carpenter)."
          }
        ],
        "level": 1,
        "verdict": "Temper choice sets corrosion resistance"
      }
    ]
  },
  "updated": "2026-10-24",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 44,
    "unreachable": 0,
    "caveats": 6,
    "note": "Read by an AI assistant on 2026-10-24 from pages fetched in this run: Rolled Alloys bulletin 1142, AircraftMaterials 440C sheet, Aalco EN 10088-3 bar datasheet, UPMET 440C datasheet, Carpenter 440C page, NASA Glenn 2018 slides, NASA/Battelle 1984 turbopump bearing report, UniMAP copy of the Springer SS440C paper, USGS MCS 2026 chromium and molybdenum, the NIOSH-authored welding fume study (PMC), Google Patents JP6207408B2 (JIS name only) and Wikipedia (composition only)."
  },
  "sources": {
    "rolled-440c": {
      "title": "Rolled Alloys: Stainless 440C data sheet (Bulletin No. 1142, 08/15)",
      "id": "Bulletin No. 1142",
      "url": "https://www.rolledalloys.ca/wp-content/uploads/440C_stainless-steel-data-sheet.pdf",
      "year": 2015,
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "aircraft-materials-440c": {
      "title": "AircraftMaterials UK: Stainless Steel 440C technical data sheet (Alloy 440C, AISI 440C, AMS 5630)",
      "id": "Alloy 440C page",
      "url": "https://www.aircraftmaterials.com/data/alstst/440c.html",
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "aalco-440c-bar": {
      "title": "Aalco: Stainless Steel - Martensitic - 1.4125 (440C) Bar, EN 10088-3:2005 datasheet",
      "id": "EN 10088-3:2005 bar",
      "url": "https://www.aalco.co.uk/datasheets/Stainless-Steel-14125-440C-Bar_312.ashx",
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "upmet-440c": {
      "title": "United Performance Metals: Alloy 440C datasheet (AMS 5630 chemistry)",
      "id": "ALLOY 440C",
      "url": "https://www.upmet.com/sites/default/files/datasheets/440c.pdf",
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "carpenter-440c": {
      "title": "Carpenter Technology: 440C alloy page (type analysis, applicable specifications, uses)",
      "id": "UNS S44004",
      "url": "https://www.carpentertechnology.com/alloy-finder/440c",
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "nasa-2018-ntrs": {
      "title": "NASA Glenn: DellaCorte, Ni-Ti Next Generation Bearings for Space Applications (Schaeffler International Bearing Conference, 24 January 2018)",
      "id": "NTRS 20180002168",
      "url": "https://ntrs.nasa.gov/api/citations/20180002168/downloads/20180002168.pdf",
      "year": 2018,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "nasa-1984-ntrs": {
      "title": "Dufrane et al., Battelle for NASA: Measurements of elastohydrodynamic film thicknesses, wear, and tempering behavior of high pressure oxygen turbopump bearings (AISI 440C)",
      "id": "NTRS 19840014892 (report dated 2 April 1984)",
      "url": "https://ntrs.nasa.gov/api/citations/19840014892/downloads/19840014892.pdf",
      "year": 1984,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "springer-unimap-440c": {
      "title": "Effects of Heat Treatment on the Properties of SS440C for Blades Applications (Springer Proceedings in Physics 289, pp. 145-152; UniMAP repository copy)",
      "id": "Springer Proc. Phys. 289, 145-152",
      "url": "https://ris.unimap.edu.my/entities/publication/1eddb8c2-050b-427f-8b49-0de618f67a03",
      "kind": "paper",
      "license": "cited, not reproduced"
    },
    "usgs-chromium-2026": {
      "title": "USGS Mineral Commodity Summaries 2026: Chromium",
      "id": "mcs2026-chromium",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-molybdenum-2026": {
      "title": "USGS Mineral Commodity Summaries 2026: Molybdenum",
      "id": "mcs2026-molybdenum",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "pmc-cr6-welding": {
      "title": "Keane M, Siert A, Stone S, Chen B, et al. (NIOSH): Selecting Processes to Minimize Hexavalent Chromium from Stainless Steel Welding (Welding Journal)",
      "id": "PMC4681305",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC4681305",
      "kind": "paper",
      "license": "open access (PMC)"
    },
    "patent-jp6207408": {
      "title": "Google Patents JP6207408B2: background text naming SUS440C and JIS G4303",
      "id": "JP6207408B2",
      "url": "https://patents.google.com/patent/JP6207408B2/en",
      "kind": "web",
      "license": "public patent text"
    },
    "wiki-440c": {
      "title": "Wikipedia: 440C (composition cross-check only)",
      "id": "440C",
      "url": "https://en.wikipedia.org/wiki/440C",
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/stainless-440c/"
}