{
  "spore": "profile",
  "id": "steel-52100",
  "spore_version": "0.2",
  "family": "bearing-steel",
  "name": "AISI 52100 bearing steel",
  "abbreviation": "52100 (UNS G52986)",
  "role": "High-carbon chromium alloy steel for rolling-element bearings",
  "category": "tribology",
  "type": "bearing-materials",
  "summary": "AISI 52100 is an iron-based, high-carbon chromium alloy steel with 0.980 to 1.10 % carbon and 1.30 to 1.60 % chromium (AZoM composition table). AZoM gives its density as 7.81 g/cm3 and its melting point as 1424 °C. Rockwell C values of 62 to 66 are printed for its quenched conditions. AZoM describes it as used in bearings in rotating machinery. A 2017 ASTM paper ranks 52100 among the bearing steels with the highest corrosion rates in simulated seawater.\n",
  "best_for": "Hard, wear-resistant rolling bearings in rotating machinery (AZoM), where corrosion exposure is limited",
  "weakest_at": "Corrosion resistance. In a 2017 electrochemical ranking in simulated seawater, 52100 had one of the highest corrosion rates of the bearing steels tested (ranking only; the abstract gives no corrosion-rate numbers)",
  "identity": {
    "formula": "Iron-based steel: Fe 96.5 to 97.32 %, C 0.980 to 1.10 %, Cr 1.30 to 1.60 %, Mn 0.250 to 0.450 %, Si 0.150 to 0.300 %, S 0.0250 max %, P 0.0250 max % (wt%)",
    "designations": [
      {
        "system": "UNS",
        "code": "G52986",
        "source": "azom-52100",
        "where": "Page title (AISI 52100 Alloy Steel (UNS G52986))"
      },
      {
        "system": "AISI",
        "code": "52100",
        "source": "azom-52100",
        "where": "Page title"
      },
      {
        "system": "SAE",
        "code": "E52100",
        "source": "totalmateria-52100",
        "where": "Cross-references list (SAE, United States)"
      },
      {
        "system": "EN",
        "code": "1.3505",
        "source": "totalmateria-52100",
        "where": "Cross-references list (WL, Germany)"
      },
      {
        "system": "JIS",
        "code": "SUJ 2",
        "source": "totalmateria-52100",
        "where": "Cross-references list (JIS, Japan)"
      },
      {
        "system": "ASTM",
        "code": "A 295",
        "note": "cross-reference printed as A 295 52100; the specification text itself was not read",
        "source": "totalmateria-52100",
        "where": "Cross-references list (ASTM, United States)"
      }
    ],
    "source": "azom-52100",
    "where": "Chemical Composition table (Element and Content columns); totalmateria Composition table gives the same C, Mn, Si, Cr, P and S ranges"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "mechanisms"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, as printed in the physical properties table",
      "value": 7.81,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "not printed",
        "temper": "not printed"
      },
      "method": "Physical properties table, metric column, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Physical Properties table, Density row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density range, 0 to 30 degC",
      "value": 7.67,
      "value_high": 7.86,
      "bound": "range",
      "unit": "kg/dm3",
      "scope": "material",
      "conditions": {
        "temperature": "0 to 30 °C",
        "temper": "not printed"
      },
      "method": "Physical properties section, as printed (range)",
      "status": "ground",
      "source": "totalmateria-52100",
      "where": "Physical properties, Density row",
      "source_detail": {
        "title": "AISI 52100 material page (Total Materia)",
        "id": "totalmateria material 1623479",
        "url": "https://www.totalmateria.com/en-us/material/1623479",
        "kind": "database",
        "license": "Total Materia terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, metric range",
      "value": 190,
      "value_high": 210,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not printed",
        "temper": "not printed"
      },
      "method": "Mechanical properties table, metric column, as printed (range)",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Elastic modulus row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, range at 0 to 30 degC",
      "value": 190,
      "value_high": 210,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "0 to 30 °C",
        "temper": "not printed"
      },
      "method": "Physical properties section, as printed (range)",
      "status": "ground",
      "source": "totalmateria-52100",
      "where": "Physical properties, Modulus of Elasticity row",
      "source_detail": {
        "title": "AISI 52100 material page (Total Materia)",
        "id": "totalmateria material 1623479",
        "url": "https://www.totalmateria.com/en-us/material/1623479",
        "kind": "database",
        "license": "Total Materia terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "value": 0.27,
      "value_high": 0.3,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "temperature": "not printed",
        "note": "dimensionless; the page prints no unit"
      },
      "method": "Mechanical properties table as printed (range)",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Poisson's ratio row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 1424,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "single value as printed in the physical properties table",
        "composition": "AISI 52100 as listed by AZoM"
      },
      "method": "Physical properties table, metric column, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Physical Properties table, Melting point row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Thermal expansion coefficient, 23 to 280 degC, annealed",
      "value": 11.9,
      "bound": "exact",
      "unit": "µm/m°C",
      "scope": "material",
      "conditions": {
        "temperature_range": "23 to 280 °C",
        "temper": "annealed"
      },
      "method": "Thermal properties table, metric column, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Thermal properties table, Thermal expansion co-efficient row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Thermal expansion coefficient, 0 to 100 degC, annealed",
      "value": 11.9,
      "bound": "exact",
      "unit": "10-6/°C",
      "scope": "material",
      "conditions": {
        "temperature_range": "0 to 100 °C",
        "temper": "annealed"
      },
      "method": "Thermal properties section, as printed",
      "status": "ground",
      "source": "totalmateria-52100",
      "where": "Thermal Properties, Thermal Expansion row",
      "source_detail": {
        "title": "AISI 52100 material page (Total Materia)",
        "id": "totalmateria material 1623479",
        "url": "https://www.totalmateria.com/en-us/material/1623479",
        "kind": "database",
        "license": "Total Materia terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_c",
      "label": "Rockwell C hardness, quenched in oil from 150 °C and tempered",
      "value": 62,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "treatment": "quenched in oil from 150 °C, tempered (as printed)",
        "scale": "Rockwell C"
      },
      "method": "Mechanical properties table, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Hardness Rockwell C (quenched in oil from 150°C tempered) row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_c",
      "label": "Rockwell C hardness, quenched in water from 150 °C and tempered",
      "value": 64,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "treatment": "quenched in water from 150 °C, tempered (as printed)",
        "scale": "Rockwell C"
      },
      "method": "Mechanical properties table, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Hardness Rockwell C (quenched in water from 150°C tempered) row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_c",
      "label": "Rockwell C hardness, quenched in oil",
      "value": 64,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "treatment": "quenched in oil (as printed; no tempering stated)",
        "scale": "Rockwell C"
      },
      "method": "Mechanical properties table, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Hardness Rockwell C (quenched in oil) row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_c",
      "label": "Rockwell C hardness, quenched in water",
      "value": 66,
      "bound": "exact",
      "unit": "HRC",
      "scope": "material",
      "conditions": {
        "treatment": "quenched in water (as printed; no tempering stated)",
        "scale": "Rockwell C"
      },
      "method": "Mechanical properties table, as printed",
      "status": "ground",
      "source": "azom-52100",
      "where": "Mechanical properties table, Hardness Rockwell C (quenched in water) row",
      "source_detail": {
        "title": "AISI 52100 Alloy Steel (UNS G52986)",
        "id": "AZoM article 6704 (published 26 Sep 2012)",
        "url": "https://www.azom.com/article.aspx?ArticleID=6704",
        "year": 2012,
        "kind": "datasheet",
        "license": "AZoM terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_unspecified_scale",
      "label": "Rockwell hardness range, scale letter not printed",
      "value": 58,
      "value_high": 65,
      "bound": "range",
      "unit": "HR",
      "scope": "material",
      "conditions": {
        "temperature": "0 to 30 °C",
        "scale": "not printed on the page",
        "treatment": "not printed"
      },
      "method": "Mechanical properties section, as printed (range)",
      "status": "ground",
      "note": "The page prints HR without a scale letter, so the scale is unknown. Do not read it as Rockwell C.",
      "source": "totalmateria-52100",
      "where": "Mechanical properties, Rockwell Hardness (HR) row",
      "source_detail": {
        "title": "AISI 52100 material page (Total Materia)",
        "id": "totalmateria material 1623479",
        "url": "https://www.totalmateria.com/en-us/material/1623479",
        "kind": "database",
        "license": "Total Materia terms (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Simulated synthetic seawater, aqueous electrochemical polarisation and impedance tests",
      "headline": "In a seawater electrochemical ranking, AISI 52100 had one of the highest corrosion rates of the bearing steels tested.",
      "effect": "Kvryan et al. (2017) ranked 52100 with CSS-42L as having the highest corrosion rates. 440C, CR30, XD15N and Pyrowear 675 (CN-A) had the lowest. The abstract gives the ranking only. The authors say that salt-spray and immersion standards lack sensitivity for steels with elevated chromium content, which is why they used electrochemistry.",
      "rating": "severe",
      "conditions": {
        "basis": "aqueous solutions at the free corrosion potential; ranking as printed in the abstract",
        "electrolyte": "simulated synthetic seawater",
        "heat_treatment": "not stated in the abstract"
      },
      "source": "kvryan-2017",
      "where": "Abstract (ASTM STP 1600, pp. 466 to 486)"
    },
    {
      "environment": "Plain tap water in a rotating spindle test, 100 h (440C races, not 52100)",
      "headline": "In a 100 h tap-water spindle test, 440C races corroded; AISI 52100 was not part of that water test.",
      "effect": "NASA's 2023 test ran hybrid 440C-race bearings and NiTi-Hf bearings in tap water for 100 h. The 440C bearings showed significant corrosion on the races and the adjacent housing spacers, and the NiTi-Hf bearings showed none. In that study 52100 was only the ball material of a separate denting test.",
      "rating": "severe",
      "conditions": {
        "bearing": "R4 hybrid bearings, 440C races with Si3N4 balls",
        "duration": "100 h",
        "environment": "plain tap water partly filling the housing, seals partly removed"
      },
      "source": "nasa-tm-2023",
      "where": "Corrosion Test Method and Results section"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Solid steel: the grouped safety data sheet (TW Metals, rev. 01/14/2016) lists 52100 among its alternate names and states that carbon, alloy and tool steels in their solid state present no inhalation, ingestion or contact health hazard.",
        "ghs": [],
        "source": "uwo-sds-steels",
        "where": "Section 1.1 (Alternate names) and Section 4.2 (Overview)"
      },
      {
        "text": "Dust and fume from burning, melting, welding, sawing, brazing, grinding and machining may be hazardous to health. The sheet lists eye, nose and throat irritation and metal fume fever as acute effects, and prolonged exposure to dusts or fumes as a respiratory hazard.",
        "ghs": [],
        "source": "uwo-sds-steels",
        "where": "Section 4.2 (Overview, Acute and Chronic effects)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Brinnelling (permanent dents in the raceways) under high static or shock load",
        "trigger": "High radial load on the ball-race contact, tested by NASA with 52100 balls, NiTi-Hf balls and silicon nitride balls",
        "consequence": "NASA reports that the load needed for a given dent depth with NiTi-Hf balls is roughly twice that needed for 52100 balls. The authors state that 52100 is less resistant to brinnelling than NiTi-Hf.",
        "severity": "moderate",
        "source": "nasa-tm-2023",
        "where": "Introduction and Background; Denting Test Method and Results (text around Figure 11)"
      },
      {
        "mode": "Corrosion pitting in marine or other aqueous environments",
        "trigger": "Exposure to seawater or other aqueous solutions",
        "consequence": "Kvryan et al. (2017) state that premature failure by corrosion pitting is a major concern in aerospace systems operating in marine environments, and they rank 52100 among the steels with the highest corrosion rates in simulated seawater.",
        "severity": "moderate",
        "source": "kvryan-2017",
        "where": "Abstract, first paragraph and ranking sentence"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "AZoM advises a spheroidising anneal at 649 °C (1200 °F) before machining to improve machinability.",
        "source": "azom-52100",
        "where": "Fabrication and Heat Treatment, Machinability"
      },
      {
        "text": "AZoM gives normalising at 872 °C (1600 °F) and heating to 816 °C (1500 °F) followed by oil quenching. Normalising is done before machining to reduce machining stress.",
        "source": "azom-52100",
        "where": "Fabrication and Heat Treatment, Heat Treatment and Normalizing text"
      },
      {
        "text": "efunda gives austenitizing at 816 to 857 °C (1500 to 1575 °F), oil quenching with no more than 1 hour before tempering, and a cold soak to -68 °C (-90 °F) or lower for at least 1 hour.",
        "source": "efunda-52100",
        "where": "Heat treatment section (austenitizing and quench)"
      }
    ],
    "mitigations": [
      {
        "text": "Use local exhaust ventilation where grinding, welding or burning makes dust or fume, and wear a NIOSH-approved dust, mist or fume respirator when welding or burning this metal.",
        "source": "uwo-sds-steels",
        "where": "Exposure controls and personal protection (respiratory protection); Precautionary statement P261"
      }
    ]
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "Rolling-element bearings in rotating machinery",
      "example": "AZoM describes AISI 52100 as used in bearings in rotating machinery.",
      "source": "azom-52100",
      "where": "Applications section"
    },
    {
      "application": "mechanisms",
      "device": "Ball material in small precision test bearings for space-mechanism research (not a flight part)",
      "example": "NASA's 2023 denting tests used 52100 balls as one of three ball materials, alongside NiTi-Hf and silicon nitride, in small precision test bearings.",
      "source": "nasa-tm-2023",
      "where": "Denting Test Method and Results section"
    }
  ],
  "supply": [
    {
      "subject": "Iron",
      "producers": [
        {
          "country": "Australia",
          "share_percent": 37.7,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 16.2,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 11.9,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 11.2,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals",
          "listed": false
        }
      ],
      "recycling": "Not read in the iron-ore summary we hold; see gaps.",
      "substitutes": [],
      "source": "usgs-mcs2026-iron-ore",
      "where": "World Mine Production table, usable ore, 2025e (world total 2,600,000 thousand t; shares calculated by Space Mushroom from the Australia 980,000, Brazil 420,000, India 310,000 and China 290,000 values). The table is iron ore, which is the feedstock of the steel's iron content, not a figure for the steel itself. Critical list: USGS 2025 list page."
    },
    {
      "subject": "Chromium",
      "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
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (Chromium, used in stainless steel)",
          "listed": true
        }
      ],
      "recycling": "Recycled chromium, contained in reported stainless-steel scrap receipts, accounted for 21% of apparent US consumption in 2025.",
      "substitutes": [
        "USGS: chromium has no substitute in stainless steel or in superalloys; chromium-containing scrap can substitute for ferrochromium in some metallurgical uses."
      ],
      "source": "usgs-mcs2026-chromium",
      "where": "World Mine Production and Reserves table, 2025e (world total 51,000 thousand t, chromium content per the table header; shares calculated by Space Mushroom from the country values); Recycling; Substitutes; critical list from the USGS 2025 list page"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "AZoM: AISI 52100 Alloy Steel (UNS G52986), materials datasheet",
      "type": "datasheet",
      "url": "https://www.azom.com/article.aspx?ArticleID=6704",
      "year": 2012
    },
    {
      "title": "efunda: AISI 52100 alloy steel properties",
      "type": "database",
      "url": "https://www.efunda.com/materials/alloys/alloy_steels/show_alloy.cfm?ID=AISI_52100&show_prop=all&Page_Title=AISI+52100"
    },
    {
      "title": "Total Materia: AISI 52100 material page",
      "type": "database",
      "url": "https://www.totalmateria.com/en-us/material/1623479"
    },
    {
      "title": "NASA/TM-20230004311: Shock- and Corrosion-Resistant Bearings for Space Mechanisms",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20230004311/downloads/TM-20230004311.pdf",
      "year": 2023
    },
    {
      "title": "Electrochemical Corrosion Test Methods for Rapid Assessment of Aerospace Bearing Steel Performance (ASTM STP 1600)",
      "type": "paper",
      "url": "https://doi.org/10.1520/STP160020160150",
      "year": 2017
    },
    {
      "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: Iron Ore",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-ore.pdf",
      "year": 2026
    },
    {
      "title": "Safety Data Sheet: Carbon, Alloy and Tool Steels AISI Grades (TW Metals, rev. 01/14/2016), copy hosted by University of Western Ontario",
      "type": "sds",
      "url": "https://www.eng.uwo.ca/files/departments-units/student-shop/2016/sds-carbon-alloy-and-tool-steels.pdf",
      "year": 2016
    }
  ],
  "gaps": [
    "No tensile strength, yield strength or fatigue strength for 52100 was found in the pages read. AZoM and efunda print hardness and modulus but no strength values.",
    "No specific heat capacity for 52100 was found.",
    "AZoM's thermal conductivity (46.6 W/mK) and its bulk modulus (140 GPa) and shear modulus (80 GPa) are labelled as typical steel, not 52100, so they are left out.",
    "No electrical resistivity, outgassing or vacuum data for 52100 was found. No space-flight use beyond the NASA test-bearing use was found.",
    "The Kvryan et al. (2017) abstract gives a corrosion ranking only. The full paper was not opened, so no 52100 corrosion-rate number is listed.",
    "No humidity, salt-spray or wet-environment test of 52100 was found. The NASA 2023 water test used 440C and NiTi-Hf bearings only.",
    "The totalmateria hardness range (58 to 65 HR) does not print a Rockwell scale letter, so its scale is unknown.",
    "The pages read give one composition range for 52100. Vacuum-degassed and other specialist variants were not separated.",
    "totalmateria also prints 1.3514 (WL, Germany) as a cross-reference. It is not listed as a designation because the page does not say it is the same grade.",
    "The ASTM A 295 and SAE specification texts were not read. Those designations are cross-references only.",
    "Manganese is on the USGS 2025 critical list, but no manganese production data were read, so it is not profiled. Carbon supply is not profiled either.",
    "No crustal abundance figure for iron or chromium was read.",
    "The USGS iron-ore summary recycling entry was not read, so iron recycling is left blank.",
    "No image with a verified licence was found, so the profile has no media entry.",
    "side_effects: no source beyond the dust and fume statement in the hazards section.",
    "Hardness uses the benchmarks hardness_rockwell_c and hardness_rockwell_unspecified_scale. Neither is in property-canon.yaml; add them to the canon before import."
  ],
  "story": {
    "why": "AISI 52100 is a high-carbon chromium steel for rolling-element bearings. AZoM describes it as used in bearings in rotating machinery. Its hardness is the reason it is chosen for bearings. NASA's 2023 bearing study used 52100 balls as one of its comparison materials, so it is a reference grade in space-mechanism research. The sources read here do not show a flight application.",
    "uses": [
      {
        "where": "Rotating-machinery bearings",
        "line": "AZoM describes AISI 52100 as used in bearings in rotating machinery."
      },
      {
        "where": "Space bearing research",
        "line": "NASA's 2023 denting tests used 52100 balls, alongside NiTi-Hf and silicon nitride balls, in small precision test bearings. This is a research use, not a flight part."
      }
    ],
    "can_do": [
      {
        "label": "Hardness",
        "line": "AZoM prints Rockwell C values of 62 and 64 for the oil and water quenched conditions it lists, and 66 for water quench. The conditions are as printed; tempering is only stated for two of the rows.",
        "benchmark": "hardness_rockwell_c",
        "scope": "material",
        "value": "62 to 66 HRC"
      },
      {
        "label": "Stiffness",
        "line": "The elastic modulus is 190 to 210 GPa, printed by both AZoM and Total Materia.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "190 to 210 GPa"
      },
      {
        "label": "Density",
        "line": "AZoM gives a density of 7.81 g/cm3 in its physical properties table.",
        "benchmark": "density",
        "scope": "material",
        "value": "7.81 g/cm3"
      },
      {
        "label": "Melting point",
        "line": "AZoM gives a melting point of 1424 °C for the grade.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1424 °C"
      }
    ],
    "compare": "In the 2017 ASTM ranking, AISI 52100 sits at the high-corrosion end of the bearing steels tested, with CSS-42L, while 440C sits at the low end. NASA's 2023 study adds that 440C bearings corroded after 100 h in tap water and NiTi-Hf bearings did not. 52100 was not part of that water test. The ranking therefore favours 440C where corrosion resistance matters, and 52100 where hardness and wear resistance come first.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Elastic modulus",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Hardness (Rockwell C)",
        "benchmark": "hardness_rockwell_c",
        "scope": "material"
      }
    ],
    "handling": [
      "Grinding, welding or burning makes dust and fume. Use local exhaust and a NIOSH-approved respirator.",
      "Spheroidising anneal at 649 °C (1200 °F) before machining, per AZoM.",
      "Austenitizing at 816 to 857 °C with an oil quench, per efunda. Cool to -68 °C (-90 °F) or lower after quenching, per efunda.",
      "Keep the supplier's own safety data sheet on file. The sheet we hold covers a family of steels, not 52100 alone."
    ],
    "good_for": [
      "Hard, wear-resistant rolling bearings in rotating machinery, per AZoM.",
      "Comparison with 440C and other bearing steels, using the 2017 ASTM corrosion ranking and the 2023 NASA bearing tests."
    ],
    "watch_out": [
      "Corrosion. In the 2017 seawater ranking 52100 had one of the highest corrosion rates. It is a poor choice where corrosion resistance is needed.",
      "Brinnelling. NiTi-Hf needed roughly twice the load of 52100 for the same dent depth in NASA's tests.",
      "Thin data. The pages read give no tensile, yield or fatigue values for 52100."
    ],
    "verdict": "AISI 52100 is a hard, through-hardened bearing steel with a density of 7.81 g/cm3 and a modulus of 190 to 210 GPa (AZoM). Its corrosion record in the sources read here is poor, and its space-relevant data are thin.",
    "recipe": {
      "line": "AISI 52100 is an iron-based steel with 0.980 to 1.10 % carbon and 1.30 to 1.60 % chromium, with small manganese and silicon additions (AZoM composition table). It is heated to 816 to 857 °C, oil quenched, then tempered (efunda).",
      "parts": [
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "The matrix that makes up nearly all of the steel."
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "The high carbon content is what lets the steel reach its printed hardness after quenching."
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "The alloying element that makes this a chromium steel. Corrosion ranking studies still place it near the high-corrosion end."
        },
        {
          "name": "Manganese",
          "symbol": "Mn",
          "role": "Minor alloying element in the composition table."
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Minor alloying element in the composition table."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The grouped safety data sheet says solid steel presents no inhalation, ingestion or contact hazard. The hazard comes from dust and fume made during processing.",
        "points": [
          {
            "label": "The solid metal",
            "line": "The sheet says carbon, alloy and tool steels in their solid state present no inhalation, ingestion or contact health hazard. It lists 52100 among its alternate names."
          },
          {
            "label": "Dust and fume",
            "line": "Burning, melting, welding, sawing, brazing, grinding and machining can make dust and fume. The sheet calls these hazardous to health and lists metal fume fever as an acute effect."
          },
          {
            "label": "Respiratory protection",
            "line": "Wear a NIOSH-approved dust, mist or fume respirator when welding or burning this metal."
          }
        ],
        "level": 0,
        "verdict": "Solid steel is not a hazard; dust and fume are."
      },
      {
        "title": "In service",
        "lead": "NASA and ASTM sources describe two service risks for 52100: brinnelling and corrosion.",
        "points": [
          {
            "label": "Brinnelling",
            "line": "In NASA's denting tests, NiTi-Hf balls needed roughly twice the load of 52100 balls to make the same dent depth."
          },
          {
            "label": "Corrosion",
            "line": "In a 2017 seawater electrochemical ranking, 52100 had one of the highest corrosion rates of the bearing steels tested."
          }
        ]
      },
      {
        "title": "Handling",
        "points": [
          {
            "label": "Machining",
            "line": "AZoM advises a spheroidising anneal at 649 °C (1200 °F) before machining."
          },
          {
            "label": "Heat treatment",
            "line": "efunda gives austenitizing at 816 to 857 °C (1500 to 1575 °F) followed by an oil quench."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 13,
    "unreachable": 0,
    "caveats": 0,
    "note": "Written by an AI assistant on 2026-11-01 from pages fetched in this run. Values are as printed on AZoM, efunda and Total Materia, and from the NASA 2023 report, the 2017 ASTM abstract, USGS MCS 2026, and the grouped SDS. Supply shares are calculated from the USGS tables. The verify-values run found 13 of 13 values and 6 of 6 designations in the source text."
  },
  "sources": {
    "azom-52100": {
      "title": "AISI 52100 Alloy Steel (UNS G52986)",
      "id": "AZoM article 6704 (published 26 Sep 2012)",
      "url": "https://www.azom.com/article.aspx?ArticleID=6704",
      "year": 2012,
      "kind": "datasheet",
      "license": "AZoM terms (cited, not reproduced)"
    },
    "efunda-52100": {
      "title": "AISI 52100 Alloy Steel, efunda properties page",
      "id": "efunda ID=AISI_52100",
      "url": "https://www.efunda.com/materials/alloys/alloy_steels/show_alloy.cfm?ID=AISI_52100&show_prop=all&Page_Title=AISI+52100",
      "kind": "database",
      "license": "efunda terms (cited, not reproduced)"
    },
    "totalmateria-52100": {
      "title": "AISI 52100 material page (Total Materia)",
      "id": "totalmateria material 1623479",
      "url": "https://www.totalmateria.com/en-us/material/1623479",
      "kind": "database",
      "license": "Total Materia terms (cited, not reproduced)"
    },
    "nasa-tm-2023": {
      "title": "Shock- and Corrosion-Resistant Bearings for Space Mechanisms",
      "id": "NASA/TM-20230004311 (Howard and DellaCorte, August 2023)",
      "url": "https://ntrs.nasa.gov/api/citations/20230004311/downloads/TM-20230004311.pdf",
      "year": 2023,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "kvryan-2017": {
      "title": "Electrochemical Corrosion Test Methods for Rapid Assessment of Aerospace Bearing Steel Performance",
      "id": "doi:10.1520/STP160020160150 (ASTM STP 1600, pp. 466 to 486)",
      "url": "https://doi.org/10.1520/STP160020160150",
      "year": 2017,
      "kind": "paper",
      "license": "publisher copyright (cited, abstract only)"
    },
    "usgs-mcs2026-chromium": {
      "title": "Mineral Commodity Summaries 2026, Chromium",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-iron-ore": {
      "title": "Mineral Commodity Summaries 2026, Iron Ore",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-ore.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit2025": {
      "title": "About the 2025 List of Critical Minerals (USGS)",
      "id": "2025 List of Critical Minerals, November 2025",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "uwo-sds-steels": {
      "title": "Safety Data Sheet: Carbon, Alloy and Tool Steels AISI Grades (TW Metals), rev. 01/14/2016",
      "id": "TW Metals MSDS # 300; copy hosted by University of Western Ontario",
      "url": "https://www.eng.uwo.ca/files/departments-units/student-shop/2016/sds-carbon-alloy-and-tool-steels.pdf",
      "year": 2016,
      "kind": "datasheet",
      "license": "supplier document, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/steel-52100/"
}