{
  "spore": "profile",
  "id": "stainless-304l",
  "spore_version": "0.2",
  "family": "stainless-austenitic",
  "name": "Stainless steel 304L",
  "abbreviation": "304L (UNS S30403)",
  "role": "corrosion-resistant structural alloy",
  "category": "metals",
  "type": "steels-and-stainless",
  "summary": "Type 304L is the low-carbon form of 304, an austenitic chromium-nickel stainless steel. Its carbon limit of 0.030 percent maximum limits chromium carbide after welding, so the grade is specified for welded parts in corrosive service. The ASTM A240 minimums printed by ATI and ICAST are 485 MPa tensile and 170 MPa yield for plate, sheet and strip, and ATI gives a density of 7.90 g/cm3. Its main limits are sensitization after holds between 450 and 900 C, and chloride service, which Carpenter rates as restricted in sea water.\n",
  "best_for": "Welded parts in corrosive service, where the as-welded condition must resist carbide precipitation",
  "weakest_at": "Sea water and chloride service: Carpenter rates 304 and 304L restricted in sea water, and no pitting number for 304L was found",
  "identity": {
    "formula": "Fe balance; 18.0 to 20.0 Cr, 8.0 to 12.0 Ni, max 0.030 C, max 2.00 Mn, max 0.75 Si, max 0.045 P, max 0.030 S, max 0.10 N (wt%). ATI prints 17.5 to 19.5 Cr for the same grade",
    "designations": [
      {
        "system": "UNS",
        "code": "S30403",
        "source": "ati-304l",
        "where": "Title block of the ATI 304L page, UNS S30403"
      },
      {
        "system": "EN",
        "code": "1.4307",
        "source": "alleima-list",
        "where": "Austenitic stainless steels table, Alleima 4LR11 row (UNS S30403, ASTM 304L, EN 1.4307)"
      },
      {
        "system": "EN",
        "code": "1.4306",
        "source": "alleima-list",
        "where": "Austenitic stainless steels table, Alleima 3R12 row (UNS S30403, ASTM 304L, EN 1.4306)"
      },
      {
        "system": "EN name",
        "code": "X2CrNi18-9",
        "source": "alloys-intl-304l",
        "where": "304L entry, W.Nr 1.4307 followed by X2CrNi18-9"
      },
      {
        "system": "AISI",
        "code": "304L",
        "source": "icast-s30403",
        "where": "Cross Reference Table, row 304L with standard AISI"
      },
      {
        "system": "JIS",
        "code": "SUS304L",
        "source": "icast-s30403",
        "where": "Cross Reference Table, row SUS 304L with standard JIS"
      },
      {
        "system": "BS",
        "code": "304 S 11",
        "source": "icast-s30403",
        "where": "Cross Reference Table, row 304 S 11 with standard BS"
      },
      {
        "system": "ASTM",
        "code": "A240",
        "note": "plate, sheet and strip; UNS S30403",
        "source": "icast-s30403",
        "where": "Title line, Material: ASTM A240 UNS S30403"
      },
      {
        "system": "ASME",
        "code": "SA-240",
        "note": "plate, sheet and strip",
        "source": "ati-304l",
        "where": "Specifications line under Plate, Sheet and Strip"
      },
      {
        "system": "ASTM",
        "code": "A666",
        "note": "plate, sheet and strip",
        "source": "ati-304l",
        "where": "Specifications line under Plate, Sheet and Strip"
      },
      {
        "system": "ASTM",
        "code": "A312",
        "note": "seamless and welded pipe",
        "source": "ati-tds-304l",
        "where": "Specifications table, Seamless and/or Welded Pipe row"
      },
      {
        "system": "ASTM",
        "code": "A182",
        "note": "flanges and fittings",
        "source": "ati-tds-304l",
        "where": "Specifications table, Flanges and Fittings row"
      },
      {
        "system": "ASTM",
        "code": "A276",
        "note": "bar and wire",
        "source": "ati-tds-304l",
        "where": "Specifications table, Bar and Wire row"
      },
      {
        "system": "ASTM",
        "code": "A479",
        "note": "bar and wire",
        "source": "ati-tds-304l",
        "where": "Specifications table, Bar and Wire row"
      }
    ],
    "source": "icast-s30403",
    "where": "Chemical Composition table of the ICAST ASTM A240 UNS S30403 data sheet. Carpenter's 304L page gives Cr 18.00 to 20.00 (nominal). The ATI 304L page gives Cr 17.5 to 19.5"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "propulsion-and-tanks",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, plate, sheet and strip (ATI 304L page)",
      "value": 7.9,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "plate, sheet and strip",
        "temperature": "not stated",
        "temper": "not stated"
      },
      "method": "Density row of the ATI 304L product page, metric value printed beside 0.285 lb/in3; the same value appears in each product form block",
      "status": "ground",
      "source": "ati-304l",
      "where": "Density row, Plate block (the Sheet and Strip blocks print the same value)",
      "source_detail": {
        "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
        "id": "ATI product page, 304L",
        "url": "https://atimaterials.com/Products/ati-304l",
        "kind": "datasheet",
        "license": "ATI web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength minimum, ASTM A240 (ATI 304L page)",
      "value": 485,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "plate, sheet and strip",
        "basis": "minimum, printed as 70 ksi min and 485 MPa min",
        "temper": "not stated"
      },
      "method": "Tensile Strength row of the ATI 304L product page, MPa value printed as 485 min",
      "status": "ground",
      "source": "ati-304l",
      "where": "Tensile Strength row, Plate block",
      "source_detail": {
        "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
        "id": "ATI product page, 304L",
        "url": "https://atimaterials.com/Products/ati-304l",
        "kind": "datasheet",
        "license": "ATI web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength minimum, ASTM A240 (ATI 304L page)",
      "value": 170,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "plate, sheet and strip",
        "basis": "minimum, printed as 25 ksi min and 170 MPa min",
        "offset": "not stated",
        "temper": "not stated"
      },
      "method": "Yield Strength row of the ATI 304L product page, MPa value printed as 170 min",
      "status": "ground",
      "source": "ati-304l",
      "where": "Yield Strength row, Plate block",
      "source_detail": {
        "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
        "id": "ATI product page, 304L",
        "url": "https://atimaterials.com/Products/ati-304l",
        "kind": "datasheet",
        "license": "ATI web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation minimum, ASTM A240 (ATI 304L page)",
      "value": 40,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "form": "plate, sheet and strip",
        "basis": "minimum as printed",
        "gauge_length": "not stated",
        "temper": "not stated"
      },
      "method": "Elongation row of the ATI 304L product page, printed as 40% min",
      "status": "ground",
      "source": "ati-304l",
      "where": "Elongation row, Plate block",
      "source_detail": {
        "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
        "id": "ATI product page, 304L",
        "url": "https://atimaterials.com/Products/ati-304l",
        "kind": "datasheet",
        "license": "ATI web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_b",
      "label": "Hardness maximum, Rockwell B (ATI 304L page)",
      "value": 92,
      "bound": "upper",
      "unit": "HRB",
      "scope": "material",
      "conditions": {
        "form": "plate, sheet and strip",
        "basis": "maximum, printed as 92 HRB max",
        "temper": "not stated"
      },
      "method": "Hardness row of the ATI 304L product page, printed as 92 HRB max",
      "status": "ground",
      "source": "ati-304l",
      "where": "Hardness row, Plate block",
      "source_detail": {
        "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
        "id": "ATI product page, 304L",
        "url": "https://atimaterials.com/Products/ati-304l",
        "kind": "datasheet",
        "license": "ATI web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength minimum, ASTM A240 (ICAST S30403 sheet)",
      "value": 485,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "product": "ASTM A240 plate, sheet and strip, UNS S30403",
        "heat_treatment": "solution annealing, printed under the Heat Treatment column",
        "basis": "minimum, printed as 485 min."
      },
      "method": "Mechanical Properties block of the ICAST ASTM A240 UNS S30403 data sheet, Tensile Strength in MPa row",
      "status": "ground",
      "source": "icast-s30403",
      "where": "Mechanical Properties, Tensile Strength in Mpa row",
      "source_detail": {
        "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet, chemical composition, mechanical properties and cross reference",
        "id": "ASTM A240 UNS S30403",
        "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf",
        "kind": "datasheet",
        "license": "stockist data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength minimum, ASTM A240 (ICAST S30403 sheet)",
      "value": 170,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "product": "ASTM A240 plate, sheet and strip, UNS S30403",
        "heat_treatment": "solution annealing, printed under the Heat Treatment column",
        "basis": "minimum, printed as 170 min.",
        "offset": "not stated"
      },
      "method": "Mechanical Properties block of the ICAST data sheet, Yield Strength in MPa row",
      "status": "ground",
      "source": "icast-s30403",
      "where": "Mechanical Properties, Yield Strength in Mpa row",
      "source_detail": {
        "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet, chemical composition, mechanical properties and cross reference",
        "id": "ASTM A240 UNS S30403",
        "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf",
        "kind": "datasheet",
        "license": "stockist data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation minimum, ASTM A240 (ICAST S30403 sheet)",
      "value": 40,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "product": "ASTM A240 plate, sheet and strip, UNS S30403",
        "heat_treatment": "solution annealing, printed under the Heat Treatment column",
        "basis": "minimum, printed as 40 min.",
        "gauge_length": "not stated"
      },
      "method": "Mechanical Properties block of the ICAST data sheet, Elongation in % row",
      "status": "ground",
      "source": "icast-s30403",
      "where": "Mechanical Properties, Elongation in % row",
      "source_detail": {
        "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet, chemical composition, mechanical properties and cross reference",
        "id": "ASTM A240 UNS S30403",
        "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf",
        "kind": "datasheet",
        "license": "stockist data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_brinell",
      "label": "Hardness maximum, Brinell (ICAST S30403 sheet)",
      "value": 201,
      "bound": "upper",
      "unit": "HB",
      "scope": "material",
      "conditions": {
        "product": "ASTM A240 plate, sheet and strip, UNS S30403",
        "heat_treatment": "solution annealing, printed under the Heat Treatment column",
        "basis": "maximum, printed as 201 max."
      },
      "method": "Mechanical Properties block of the ICAST data sheet, Hardness in HB row",
      "status": "ground",
      "source": "icast-s30403",
      "where": "Mechanical Properties, Hardness in HB row",
      "source_detail": {
        "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet, chemical composition, mechanical properties and cross reference",
        "id": "ASTM A240 UNS S30403",
        "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf",
        "kind": "datasheet",
        "license": "stockist data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, 304L column (UPMET Alloy 304 sheet)",
      "value": 241,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "column": "304L",
        "offset": "0.2%",
        "basis": "table value; minimum or typical not stated",
        "temper": "not stated",
        "unit_in_source": "35 (241) under header psi (MPa)"
      },
      "method": "Mechanical Properties table, 0.2% Offset Yield Strength row, 304L column; the MPa value in brackets is taken as printed",
      "status": "ground",
      "source": "upmet-304-304l",
      "where": "Mechanical Properties of 304 table, 0.2% Offset Yield Strength row, 304L column",
      "source_detail": {
        "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
        "id": "UNS S30400, AMS 5513",
        "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, 304L column (UPMET Alloy 304 sheet)",
      "value": 586,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "column": "304L",
        "basis": "table value; minimum or typical not stated",
        "temper": "not stated",
        "unit_in_source": "85 (586) under header psi (MPa)"
      },
      "method": "Mechanical Properties table, Ultimate Tensile Strength row, 304L column; the MPa value in brackets is taken as printed",
      "status": "ground",
      "source": "upmet-304-304l",
      "where": "Mechanical Properties of 304 table, Ultimate Tensile Strength row, 304L column",
      "source_detail": {
        "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
        "id": "UNS S30400, AMS 5513",
        "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, 304L column (UPMET Alloy 304 sheet)",
      "value": 55,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "column": "304L",
        "gauge_length": "2 in (50.8 mm), as printed",
        "basis": "table value; minimum or typical not stated",
        "temper": "not stated"
      },
      "method": "Mechanical Properties table, Elongation row, 304L column",
      "status": "ground",
      "source": "upmet-304-304l",
      "where": "Mechanical Properties of 304 table, Elongation in 2 in. row, 304L column",
      "source_detail": {
        "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
        "id": "UNS S30400, AMS 5513",
        "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_rockwell_b",
      "label": "Hardness, 304L column, Rockwell B (UPMET Alloy 304 sheet)",
      "value": 80,
      "bound": "exact",
      "unit": "HRB",
      "scope": "material",
      "conditions": {
        "column": "304L",
        "scale": "Rockwell B, printed as B80",
        "basis": "table value; minimum or typical not stated",
        "temper": "not stated"
      },
      "method": "Mechanical Properties table, Hardness Rockwell row, 304L column, printed as B80",
      "status": "ground",
      "source": "upmet-304-304l",
      "where": "Mechanical Properties of 304 table, Hardness Rockwell row, 304L column",
      "source_detail": {
        "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
        "id": "UNS S30400, AMS 5513",
        "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus in tension (ATI shared table)",
      "value": 200,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "loading": "tension",
        "basis": "printed as 29 x 10^6 psi (200 GPa) in one table shared by ATI 302, 304, 304L and 305",
        "temperature": "not stated"
      },
      "method": "Physical Properties page of the ATI 302/304/304L/305 technical data sheet, Modulus of Elasticity in Tension row; the table is not split by grade",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Modulus of Elasticity in Tension",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion, 20 to 100 C (ATI shared table)",
      "value": 16.6,
      "bound": "exact",
      "unit": "10-6 cm/cm/°C",
      "scope": "material",
      "conditions": {
        "temperature_range": "20 to 100 C (68 to 212 F)",
        "basis": "mean coefficient; one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Linear Coefficient of Thermal Expansion table, cm/cm/°C column at 20 to 100 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Linear Coefficient of Thermal Expansion, 20 to 100 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion, 20 to 870 C (ATI shared table)",
      "value": 19.8,
      "bound": "exact",
      "unit": "10-6 cm/cm/°C",
      "scope": "material",
      "conditions": {
        "temperature_range": "20 to 870 C (68 to 1600 F)",
        "basis": "mean coefficient; one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Linear Coefficient of Thermal Expansion table, cm/cm/°C column at 20 to 870 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Linear Coefficient of Thermal Expansion, 20 to 870 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 100 C (ATI shared table)",
      "value": 16.3,
      "bound": "exact",
      "unit": "W/m·K",
      "scope": "material",
      "conditions": {
        "temperature": "100 C (212 F)",
        "basis": "one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Thermal Conductivity table, W/m K column at 100 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Thermal Conductivity, 212 F / 100 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 500 C (ATI shared table)",
      "value": 21.4,
      "bound": "exact",
      "unit": "W/m·K",
      "scope": "material",
      "conditions": {
        "temperature": "500 C (932 F)",
        "basis": "one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Thermal Conductivity table, W/m K column at 500 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Thermal Conductivity, 932 F / 500 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat, 0 to 100 C (ATI shared table)",
      "value": 500,
      "bound": "exact",
      "unit": "J/kg·K",
      "scope": "material",
      "conditions": {
        "temperature_range": "0 to 100 C (32 to 212 F)",
        "basis": "one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Specific Heat table, J/kg K column for 0 to 100 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Physical Properties, Specific Heat, 32 to 212 F / 0 to 100 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity at 20 C (ATI shared table)",
      "value": 72,
      "bound": "exact",
      "unit": "microhm-cm",
      "scope": "material",
      "conditions": {
        "temperature": "20 C (68 F)",
        "basis": "one table shared by ATI 302, 304, 304L and 305"
      },
      "method": "Electrical Resistivity table, Microhm-cm column at 20 C",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Electrical Resistivity table, 68 F / 20 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting range (ATI shared table)",
      "value": 1399,
      "value_high": 1421,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "melting range as printed, 2,550 to 2,590 F",
        "temperature": "not applicable"
      },
      "method": "Melting Range table, range printed in C and F; the C values are taken as printed",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Melting Range table, 2,550 to 2,590 F / 1,399 to 1,421 C row",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum use temperature, ASME coverage for ATI 304L",
      "value": 426,
      "bound": "upper",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "ASME Section II Part D coverage limit printed for ATI 304L: maximum use temperature 800 F (426 C), with lower allowable stresses than 304",
        "temperature": "not applicable"
      },
      "method": "Specifications and Certificates section (page 2) of the ATI 302/304/304L/305 data sheet, ASME paragraph; a code coverage limit, not a melting or oxidation limit",
      "status": "ground",
      "source": "ati-tds-304l",
      "where": "Specifications and Certificates, ASME paragraph",
      "source_detail": {
        "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
        "id": "ATI TDS, version 1 (2/17/2014)",
        "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
        "year": 2014,
        "kind": "datasheet",
        "license": "supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Mean coefficient of thermal expansion, 32 to 1200 F (CarTech 304/304L sheet)",
      "value": 10.4,
      "bound": "exact",
      "unit": "10-6 in/in/°F",
      "scope": "material",
      "conditions": {
        "temperature_range": "32 to 1200 F (printed in F only)",
        "basis": "mean CTE; combined 304 and 304L data sheet"
      },
      "method": "Physical Properties block, Mean CTE row, printed in imperial units only and not converted",
      "status": "ground",
      "source": "carpenter-304-304l-datasheet",
      "where": "Physical Properties, Mean CTE (32 to 1200 F) row",
      "source_detail": {
        "title": "CarTech 304/304L Stainless data sheet (Carpenter Technology, combined 304 and 304L)",
        "id": "CarTech 304/304L Stainless, edition date 07/01/2000, copyright 2020",
        "url": "https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/304L.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "safe_scaling_temperature",
      "label": "Safe scaling temperature for continuous service (CarTech 304/304L sheet)",
      "value": 871,
      "bound": "upper",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "continuous service, printed as 1600 F (871 C)",
        "temperature": "continuous service"
      },
      "method": "Scaling section, safe scaling temperature for continuous service, printed in F with C in brackets",
      "status": "ground",
      "source": "carpenter-304-304l-datasheet",
      "where": "Scaling section",
      "source_detail": {
        "title": "CarTech 304/304L Stainless data sheet (Carpenter Technology, combined 304 and 304L)",
        "id": "CarTech 304/304L Stainless, edition date 07/01/2000, copyright 2020",
        "url": "https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/304L.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_brinell",
      "label": "Hardness after annealing, Brinell (CarTech 304/304L sheet)",
      "value": 150,
      "bound": "exact",
      "unit": "HB",
      "scope": "material",
      "conditions": {
        "temper": "annealed: heat to 1010/1121 C (1850/2050 F) and quench in water",
        "basis": "printed as approximately 150; a typical value, not a limit"
      },
      "method": "Heat Treatment, Annealing paragraph, Brinell hardness printed as approximately 150",
      "status": "ground",
      "source": "carpenter-304-304l-datasheet",
      "where": "Heat Treatment, Annealing paragraph",
      "source_detail": {
        "title": "CarTech 304/304L Stainless data sheet (Carpenter Technology, combined 304 and 304L)",
        "id": "CarTech 304/304L Stainless, edition date 07/01/2000, copyright 2020",
        "url": "https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/304L.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hydrogen_outgassing_rate",
      "label": "Hydrogen outgassing rate of an unfired 304L vacuum chamber",
      "value": 9.4,
      "bound": "exact",
      "unit": "×10-10 Pa L s-1 cm-2",
      "scope": "material",
      "conditions": {
        "chamber": "unfired 304L chamber, no vacuum-fire heat treatment",
        "temperature": "298.15 K",
        "pre_bake": "125 to 150 C for at least 72 h before rate-of-rise measurement",
        "basis": "Table IV value, printed as 9.4 x 10-10 with the exponent kept in the unit"
      },
      "method": "Table IV of the NIST paper, QH2 at 298.15 K, determined from the fitting parameters A0 and ED for the non-titanium chambers; the value is for one chamber made of 304L, not a bulk-material test",
      "status": "calculated",
      "uncertainty": "24 percent (uQH2 for the 304L chamber)",
      "note": "Table IV gives a relative improvement factor of 184 for the vacuum-fired 316L-XHV chamber against the 304L chamber. The abstract's range of 4.0 to 8.0 x 10-11 covers the unfired 304L, 316L and 316LN chambers together and is not split by grade, so it is not recorded as a 304L value.",
      "source": "nist-vacuum-2020",
      "where": "Table IV, row 304L (QH2 at 298.15 K column); abstract for bake conditions",
      "source_detail": {
        "title": "Fedchak et al.: Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments",
        "id": "arXiv:2009.10560 (DOI 10.1116/6.0000657)",
        "url": "https://arxiv.org/pdf/2009.10560",
        "year": 2020,
        "kind": "paper",
        "license": "arXiv preprint (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Sea water",
      "headline": "Carpenter rates 304 and 304L restricted in sea water on its comparative scale. No pitting or critical temperature for 304L was found.",
      "effect": "The CarTech 304/304L data sheet lists Sea Water as Restricted on a four-level comparative scale and says corrosion testing is recommended, because temperature, concentration, pH, crevices, deposits and surface finish all affect resistance.",
      "rating": "unknown",
      "conditions": {
        "printed_rating": "Restricted",
        "scale": "four-level comparative scale, comparison only",
        "basis": "the data sheet covers 304 and 304L together"
      },
      "source": "carpenter-304-304l-datasheet",
      "where": "Corrosion Resistance table, Sea Water row, and the Important Note"
    },
    {
      "environment": "Salt spray (NaCl)",
      "headline": "Carpenter rates salt spray Good for 304 and 304L, in contrast with the restricted rating for sea water.",
      "effect": "On the same comparative scale, salt spray (sodium chloride) is rated Good. The sheet calls the scale comparative only.",
      "rating": "low",
      "conditions": {
        "printed_rating": "Good",
        "basis": "comparative scale, no test conditions given"
      },
      "source": "carpenter-304-304l-datasheet",
      "where": "Corrosion Resistance table, Salt Spray (NaCl) row"
    },
    {
      "environment": "Warm chloride environments and chloride stress corrosion",
      "headline": "Wikipedia says 304, which it also says has the same corrosion resistance as 304L, is subject to pitting and crevice corrosion in warm chlorides.",
      "effect": "Wikipedia says 304 is subject to pitting and crevice corrosion in warm chloride environments and to stress corrosion cracking above about 60 C (140 F). It says 316 is commonly used in place of 304 when chloride pitting or crevice corrosion is too severe. The article is about 304, so these statements are a 304 comparison, not 304L values.",
      "rating": "moderate",
      "conditions": {
        "temperature": "stress corrosion cracking above about 60 C (140 F), as printed for 304",
        "basis": "Wikipedia corrosion section for 304; the article says 304, 304H and 304L have the same corrosion resistance"
      },
      "source": "wiki-304",
      "where": "Corrosion resistance section of the 304 stainless steel article; Carbon content section"
    },
    {
      "environment": "Nitric acid",
      "headline": "Carpenter rates nitric acid Good for 304 and 304L on its comparative scale.",
      "effect": "On the CarTech 304/304L comparative scale, nitric acid is rated Good. The sheet says the four-level ratings are for comparison and recommends corrosion testing, because concentration and temperature change the result.",
      "rating": "low",
      "conditions": {
        "printed_rating": "Good",
        "concentration": "not stated",
        "temperature": "not stated"
      },
      "source": "carpenter-304-304l-datasheet",
      "where": "Corrosion Resistance table, Nitric Acid row"
    },
    {
      "environment": "Sulfuric acid",
      "headline": "Carpenter rates sulfuric acid Moderate for 304 and 304L on its comparative scale.",
      "effect": "The same comparative table rates sulfuric acid Moderate, as it does phosphoric acid, acetic acid, sodium hydroxide and sour oil or gas. Each is a comparison, not a limit.",
      "rating": "moderate",
      "conditions": {
        "printed_rating": "Moderate",
        "concentration": "not stated",
        "temperature": "not stated"
      },
      "source": "carpenter-304-304l-datasheet",
      "where": "Corrosion Resistance table, Sulfuric Acid row"
    },
    {
      "environment": "Heating or slow cooling through 450 to 900 C, as in a weld heat-affected zone",
      "headline": "Chromium carbide forms at grain boundaries in this range. The 0.030 percent carbon maximum of 304L limits it.",
      "effect": "Thermal Processing says chromium carbide precipitates at grain boundaries between 450 and 900 C when carbon is above about 0.02 percent. It says the L designation holds carbon below 0.030 percent to improve weldability and limit chromium carbide. Wikipedia gives a sensitization range of 480 to 820 C and a 0.035 percent maximum for 304L, which differs from the 0.030 percent printed on the datasheets.",
      "rating": "moderate",
      "conditions": {
        "temperature": "450 to 900 C (Thermal Processing); 480 to 820 C (Wikipedia)",
        "carbon_threshold": "above about 0.02 percent",
        "carbon_limit_L": "below 0.030 percent",
        "basis": "general austenitic steel statement that applies to the L designation"
      },
      "source": "thermal-processing",
      "where": "Sensitization of Austenitic Stainless Steels, Introduction and L designation paragraphs"
    },
    {
      "environment": "Welded structures in the most severe corrosive service",
      "headline": "Carpenter says welds keep their corrosion resistance, but the welded structure should be reannealed for the most severe environments.",
      "effect": "The CarTech 304/304L data sheet says the alloy can be welded without loss of corrosion resistance from intergranular carbide precipitation and is usually used in the as-welded condition. For service in the most severe environments it advises reannealing the welded structure.",
      "rating": "unknown",
      "conditions": {
        "condition": "as-welded, or reannealed for the most severe service",
        "basis": "qualitative statement, no test conditions given"
      },
      "source": "carpenter-304-304l-datasheet",
      "where": "Weldability section"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem aggregated GHS for elemental nickel (CID 935, signal Danger): H317 May cause an allergic skin reaction; H351 Suspected of causing cancer; H372 Causes damage to organs through prolonged or repeated exposure. PubChem reports that 0.1 percent (5 of 4,778) of company reports say it does not meet GHS criteria. The data cover the element, not the alloy.",
        "ghs": [
          "H317",
          "H351",
          "H372"
        ],
        "source": "pubchem-nickel",
        "where": "Safety and Hazards, GHS Classification (aggregated), CID 935"
      },
      {
        "text": "PubChem aggregated GHS for elemental chromium (CID 23976, signal Danger): H317 (20.7 percent notified ratio) May cause an allergic skin reaction; H319 (19.1 percent) Causes serious eye irritation; H334 (20.3 percent) May cause allergy or asthma symptoms or breathing difficulties if inhaled. Half of 2,404 reports (1,202) say it does not meet GHS criteria. The data cover the element, not the alloy.",
        "ghs": [
          "H317",
          "H319",
          "H334"
        ],
        "source": "pubchem-chromium",
        "where": "Safety and Hazards, GHS Classification (aggregated), CID 23976"
      }
    ],
    "failure_risks": [
      {
        "mode": "Intergranular (sensitization) corrosion after welding or slow cooling",
        "trigger": "Holding or slow cooling between 450 and 900 C, as in a weld heat-affected zone",
        "consequence": "Chromium carbide at grain boundaries leaves the boundary open to attack. The 0.030 percent carbon maximum makes this much less likely than in 304, which Wikipedia gives a 0.08 percent carbon maximum.",
        "severity": "moderate",
        "source": "thermal-processing",
        "where": "Sensitization of Austenitic Stainless Steels"
      },
      {
        "mode": "Pitting, crevice and chloride stress corrosion in sea water",
        "trigger": "Sea water service, which Carpenter rates as restricted for 304 and 304L",
        "consequence": "The datasheets read give no critical pitting temperature or chloride limit for 304L. Carpenter recommends corrosion testing before use in this service.",
        "severity": "high",
        "source": "carpenter-304-304l-datasheet",
        "where": "Corrosion Resistance table, Sea Water row, and the Important Note"
      },
      {
        "mode": "Hydrogen outgassing in ultra-high vacuum",
        "trigger": "Unfired 304L chamber after a 125 to 150 C bake for at least 72 hours",
        "consequence": "The NIST fit gives 9.4 x 10-10 Pa L s-1 cm-2 at 298.15 K for 304L (Table IV). The vacuum-fired 316L-XHV chamber is listed with a relative improvement factor of 184 over 304L.",
        "severity": "moderate",
        "source": "nist-vacuum-2020",
        "where": "Table IV, rows 304L and 316L-XHV; abstract for the bake conditions"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Specify 304L rather than 304 for welded parts in corrosive service. Wikipedia says 304, with a 0.08 percent carbon maximum, is not useful where welding is required, and that 304L is preferred.",
        "source": "wiki-304",
        "where": "Carbon content section"
      },
      {
        "text": "Anneal at 1010 to 1121 C (1850 to 2050 F) and quench in water. Forgings must be annealed for full corrosion resistance.",
        "source": "carpenter-304-304l-datasheet",
        "where": "Heat Treatment, Annealing paragraph, and Forging section"
      },
      {
        "text": "Reanneal welded structures that will see the most severe environments, as Carpenter advises.",
        "source": "carpenter-304-304l-datasheet",
        "where": "Weldability section"
      },
      {
        "text": "The ATI and ICAST datasheets give ASTM A240 minimums only. Check the mill certificate for the form and temper being bought.",
        "source": "ati-304l",
        "where": "Tensile, Yield and Elongation rows (minimum values)"
      },
      {
        "text": "Cold work raises magnetic permeability. The 18-8 alloys are generally non-magnetic in the annealed condition, according to the ATI data sheet.",
        "source": "ati-tds-304l",
        "where": "Magnetic Permeability section"
      }
    ],
    "mitigations": [
      {
        "text": "For ultra-high vacuum, NIST vacuum-fired 316L and 316LN at about 950 C for 24 hours under vacuum. No vacuum-fired 304L chamber was tested, so the vacuum-firing benefit is not claimed for 304L.",
        "source": "nist-vacuum-2020",
        "where": "Abstract, vacuum-fire process and chamber list"
      },
      {
        "text": "Use the low-carbon grade in welds. The 0.030 percent carbon maximum limits carbide precipitation during welding, according to Carpenter.",
        "source": "carpenter-304l",
        "where": "Opening description, 304L page"
      }
    ]
  },
  "uses": [
    {
      "application": "propulsion-and-tanks",
      "device": "Starship SN7 test tank and Starship SN8 prototype",
      "example": "Wikipedia says early Starships used SAE 301 stainless steel, then SAE 304L for the SN7 test tank and Starship SN8 in 2020. This is a use report, not a test result for the alloy.",
      "source": "wiki-304",
      "where": "Applications section, Starship sentence"
    },
    {
      "application": "structures",
      "device": "Vacuum chamber walls (laboratory)",
      "example": "NIST chose 304L as its benchmark because it is one of the most commonly used materials for vacuum chambers in the United States. Table IV gives 9.4 x 10-10 Pa L s-1 cm-2 at 298.15 K for its unfired 304L chamber.",
      "source": "nist-vacuum-2020",
      "where": "Introduction, benchmark paragraph; Table IV"
    },
    {
      "application": "structures",
      "device": "Welded products in corrosive service",
      "example": "ATI says 304L is used for welded products that might be exposed to conditions which could cause intergranular corrosion in service.",
      "source": "ati-tds-304l",
      "where": "Introduction, ATI 304L paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Nickel",
      "abundance": "Stainless and alloy steel plus nickel-containing alloys typically account for more than 85 percent of US domestic consumption. World reserves are more than 140,000,000 t, of which Indonesia holds 62,000,000 t (USGS 2026).",
      "producers": [
        {
          "country": "Indonesia",
          "share_percent": 66.7,
          "year": 2025
        },
        {
          "country": "Philippines",
          "share_percent": 6.9,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.1,
          "year": 2025
        },
        {
          "country": "New Caledonia",
          "share_percent": 3.6,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 3.6,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 3.1,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "Nickel recovered from scrap accounted for about 60 percent of US apparent consumption in 2025, and most recycled nickel goes into new alloys and stainless steel (USGS 2026).",
      "substitutes": [
        "Low-nickel, duplex or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction (USGS 2026)",
        "Titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments (USGS 2026)"
      ],
      "source": "usgs-nickel-2026",
      "where": "World Mine Production and Reserves table (2025e), Domestic Production and Use, Recycling and Substitutes. Shares are computed from the 3,900,000 t 2025e world total"
    },
    {
      "subject": "Nickel import reliance, United States",
      "abundance": "US net import reliance was 41 percent of apparent consumption in 2025 (estimated) (USGS 2026).",
      "producers": [],
      "critical_lists": [],
      "recycling": "Recycled nickel was about 60 percent of apparent consumption in 2025.",
      "substitutes": [],
      "source": "usgs-nickel-2026",
      "where": "Salient Statistics, net import reliance row (2025e)"
    },
    {
      "subject": "Chromium",
      "abundance": "World resources are greater than 12 billion t of shipping-grade chromite, and 95 percent of world chromium resources lie 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
        }
      ],
      "critical_lists": [],
      "recycling": "Recycled chromium in 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 (USGS 2026)"
      ],
      "source": "usgs-chromium-2026",
      "where": "World Mine Production and Reserves table (2025e, gross weight). Shares are computed from the 51,000 thousand t world total. Substitutes and Recycling"
    },
    {
      "subject": "Chromium import reliance, United States",
      "abundance": "US net import reliance was 79 percent of apparent consumption in 2025 (estimated). Chromite imports 2021 to 2024: South Africa 96 percent, Turkey 3 percent (USGS 2026).",
      "producers": [],
      "critical_lists": [],
      "recycling": "Recycled chromium was 21 percent of apparent consumption in 2025.",
      "substitutes": [],
      "source": "usgs-chromium-2026",
      "where": "Salient Statistics, net import reliance row; Import Sources (2021 to 2024)"
    },
    {
      "subject": "Critical-mineral status",
      "abundance": "Nickel and chromium are both on the USGS 2025 List of Critical Minerals (60 minerals). The list describes chromium as used in stainless steel and nickel as used to make high-strength steel and rechargeable batteries.",
      "producers": [],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals: nickel",
          "listed": true
        },
        {
          "list": "USGS 2025 List of Critical Minerals: chromium",
          "listed": true
        }
      ],
      "substitutes": [],
      "source": "usgs-crit-2025",
      "where": "List entries on the About the 2025 List of Critical Minerals page (Chromium and Nickel rows). The EU critical raw materials list was not fetched"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
      "type": "datasheet",
      "url": "https://atimaterials.com/Products/ati-304l"
    },
    {
      "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
      "type": "datasheet",
      "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
      "year": 2014
    },
    {
      "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet",
      "type": "datasheet",
      "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf"
    },
    {
      "title": "Carpenter Technology: 304L alloy page (type analysis, applicable specifications)",
      "type": "datasheet",
      "url": "https://www.carpentertechnology.com/alloy-finder/304L"
    },
    {
      "title": "CarTech 304/304L Stainless data sheet (Carpenter Technology)",
      "type": "datasheet",
      "url": "https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/304L.pdf"
    },
    {
      "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
      "type": "datasheet",
      "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
      "year": 2026
    },
    {
      "title": "Alleima: list of alloys (billets and blooms), grade table with UNS, ASTM and EN steel numbers",
      "type": "datasheet",
      "url": "https://www.alleima.com/cz/products/billets-and-blooms/list-of-alloys"
    },
    {
      "title": "Alloys International: stainless steel 304L page (W.Nr and EN names)",
      "type": "datasheet",
      "url": "https://alloysintl.com/inventory/stainless-steel/stainless_steel304L/"
    },
    {
      "title": "Fedchak et al.: Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments (arXiv:2009.10560)",
      "type": "paper",
      "url": "https://arxiv.org/pdf/2009.10560",
      "year": 2020
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Nickel",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Chromium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026
    },
    {
      "title": "USGS: About the 2025 List of Critical Minerals",
      "type": "report",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025
    },
    {
      "title": "PubChem: Nickel (CID 935), GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/935"
    },
    {
      "title": "PubChem: Chromium (CID 23976), GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23976"
    }
  ],
  "gaps": [
    "No Outokumpu, Aperam, Aalco or Combined Metals 304L datasheet was fetched. The one Combined Metals URL tried returned not found, no Aalco or Outokumpu 304L URL was known, and web search was unavailable in this session.",
    "Physical properties (modulus, CTE, thermal conductivity, specific heat, resistivity, melting range) are printed in ATI's table for ATI 302, 304, 304L and 305 together, not split by grade. The CarTech 304/304L sheet is also combined. No 304L-only physical-property sheet was found.",
    "Chromium range: ATI's 304L page and technical data sheet print 17.5 to 19.5 weight percent. ICAST's ASTM A240 sheet and Carpenter print 18.0 to 20.0. The recipe uses 18.0 to 20.0, and the disagreement is not resolved.",
    "Silicon maximum: Carpenter prints 1 (1.00 on its data sheet), against 0.75 on the ATI and ICAST sheets. The 0.75 value is used.",
    "Carbon: Wikipedia gives a 0.035 percent maximum for 304L, while the ATI, ICAST and Carpenter sheets print 0.030 percent maximum. The datasheet value is used.",
    "Outgassing: NIST's abstract gives 4.0 to 8.0 x 10-11 Pa L s-1 cm-2 for the unfired 304L, 316L and 316LN chambers together. That range is not split by grade, so only the Table IV value for 304L alone is recorded. The NIST chamber composition for 304L (one heat, with molybdenum 0.28 to 0.43) is not the grade limit and is not used.",
    "UPMET's datasheet is headed Alloy 304 (UNS S30400). Only its 304L mechanical column is used. Its 304 composition and physical properties are not used. The 304L column does not state temper or whether the values are typical or minimum.",
    "Hardness: ATI gives 92 HRB maximum and ICAST gives 201 HB maximum (both ASTM A240 limits). Carpenter gives an annealed Brinell of about 150 (typical). UPMET gives Rockwell B80 for 304L, with the basis not stated.",
    "Wikipedia gives the minimum tensile strength of 304L as 34 MPa (5,000 psi) below that of 304. The comparison appears in the story only, not as a 304L property.",
    "Magnetic permeability values in the ATI table print no unit, so they are left out. The 304L column of that table shows the rise with cold work, which is noted in handling.",
    "Pitting resistance equivalent number, critical pitting temperature and chloride limits for 304L were not found on the pages fetched. Sea water is only rated Restricted by Carpenter.",
    "Sigma phase and 650 C embrittlement data for 304L were not found. The sigma-phase study used for 316L is not for this grade.",
    "Designations: the grade names F304L (ASTM A182) and TP304L (ASTM A312) are not printed on the pages fetched, so those entries carry the specification number only. The EN name X2CrNi19-11 for EN 1.4306 was not printed on any page fetched. GOST 04CH18N10, printed on ICAST's cross-reference row, was not added. Alleima trade grades 4LR11 and 3R12 are not used as designations.",
    "Critical minerals: the EU critical raw materials list was not fetched.",
    "Hazards: PubChem records are for elemental nickel and chromium, not for the alloy. No 304L safety data sheet with a GHS classification was fetched. Welding fume hazard was not sourced.",
    "Vacuum firing: NIST did not vacuum-fire a 304L chamber, so no vacuum-fired 304L value is recorded.",
    "No flight, space-thermal, radiation or cryogenic test result for 304L was found. The SpaceX tank use is a Wikipedia statement about use, not a test.",
    "Sensitization range differs between sources: 450 to 900 C (Thermal Processing) and 480 to 820 C (Wikipedia). Both are kept with their source.",
    "The CarTech 304/304L sheet gives typical or average values and does not guarantee maximum or minimum values. Its edition date is printed as 07/01/2000 with a 2020 copyright.",
    "The USGS critical-minerals page returned HTTP 403 to a plain curl agent and was read with a browser user agent. The verification step cannot reach it, but no property cites it.",
    "Benchmarks not in property-canon, used as short snake_case names: hardness_rockwell_b, hardness_brinell, hydrogen_outgassing_rate and safe_scaling_temperature. Hardness and outgassing are not in the canonical list; the printed units are kept as printed."
  ],
  "story": {
    "why": "Type 304L is the low-carbon version of the 18-8 austenitic stainless steel, the most frequently used alloy in the stainless family (ATI). Its carbon limit of 0.030 percent is there to limit chromium carbide after welding, so the grade is chosen for welded parts that must resist corrosion. Carpenter describes it as suited to the as-welded condition in corrosive applications, and lists food processing and dairy equipment for 304 and 304L. NIST chose it as the benchmark for vacuum chambers, and SpaceX moved to 304L for its Starship SN7 test tank and SN8 prototype.",
    "uses": [
      {
        "where": "Starship test tank and prototype",
        "line": "Wikipedia says early Starships used an earlier stainless grade, then SAE 304L for the SN7 test tank and Starship SN8 in 2020. That is a use report, not a test result for the alloy."
      },
      {
        "where": "Vacuum chambers",
        "line": "NIST benchmarked against 304L, one of the most commonly used materials for vacuum chambers in the United States. Its unfired 304L chamber had a hydrogen outgassing rate of 9.4 x 10-10 Pa L s-1 cm-2 at 298.15 K (Table IV)."
      },
      {
        "where": "Welded corrosive service",
        "line": "ATI says 304L is used for welded products that might be exposed to conditions which could cause intergranular corrosion in service."
      }
    ],
    "can_do": [
      {
        "label": "Strength",
        "line": "ASTM A240 minimums for plate, sheet and strip are 485 MPa tensile and 170 MPa yield, with elongation of at least 40 percent (ATI and ICAST). The ATI maximum hardness is 92 HRB.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Density",
        "line": "Density is 7.90 g/cm3 on the ATI 304L page.",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Heat",
        "line": "The melting range is 1,399 to 1,421 C in ATI's table, which covers 302, 304, 304L and 305 together.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1399 to 1421 C"
      },
      {
        "label": "Vacuum",
        "line": "In NIST's Table IV, an unfired 304L chamber has a hydrogen outgassing rate of 9.4 x 10-10 Pa L s-1 cm-2 at 298.15 K. The table gives a relative improvement factor of 184 for the vacuum-fired 316L-XHV chamber against 304L.",
        "benchmark": "hydrogen_outgassing_rate",
        "scope": "material",
        "value": "9.4 x 10-10 Pa L s-1 cm-2"
      }
    ],
    "compare": "Wikipedia says 304, 304H and 304L share the same nominal chromium and nickel content and the same corrosion resistance. The difference is carbon: Wikipedia gives a maximum of 0.08 percent for 304 and 0.035 percent for 304L, while the datasheets print 0.030 percent for 304L. Wikipedia also says the specified minimum tensile strength of 304L is 34 MPa (5,000 psi) lower than that of 304. The physical values in this profile come from tables that cover 304L together with other grades.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Tensile strength (minimum)",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Melting range",
        "benchmark": "melting_point",
        "scope": "material"
      }
    ],
    "handling": [
      "Specify 304L rather than 304 for welded parts in corrosive service. Wikipedia says 304 is not useful where welding is required, and that 304L is preferred.",
      "Anneal at 1010 to 1121 C and quench in water. Forgings must be annealed for full corrosion resistance (Carpenter).",
      "Avoid holding 304L between 450 and 900 C during fabrication or service, because chromium carbide forms in that range.",
      "For ultra-high vacuum, the NIST vacuum-firing benefit was tested on 316L and 316LN, not 304L. Check the mill certificate for the form and temper being bought."
    ],
    "good_for": [
      "Welded, corrosion-resistant parts in the as-welded condition, where carbide precipitation at the weld must be limited (Carpenter).",
      "Food, dairy and processing equipment, which Carpenter lists for 304 and 304L (pipelines, buckets, sterilizers).",
      "Vacuum chambers where the outgassing of an unfired 304L chamber, 9.4 x 10-10 Pa L s-1 cm-2 at 298.15 K, is acceptable (NIST Table IV)."
    ],
    "watch_out": [
      "Sea water. Carpenter rates 304 and 304L restricted in sea water, and no pitting number for 304L was found.",
      "Sensitization. Holds between 450 and 900 C form chromium carbide at grain boundaries.",
      "Vacuum outgassing. NIST Table IV gives the vacuum-fired 316L-XHV chamber a relative improvement factor of 184 over 304L."
    ],
    "verdict": "304L is the welded, low-carbon choice of the 18-8 family. Use it where carbide precipitation at a weld would matter. In sea water Carpenter rates it restricted, and Wikipedia says 316 is commonly used in place of 304 where chloride pitting is too severe.",
    "recipe": {
      "line": "304L is an iron-based austenitic stainless steel. The ICAST ASTM A240 sheet for UNS S30403 gives 18 to 20 percent chromium and 8 to 12 percent nickel, with carbon at 0.030 percent maximum and iron as the balance. The ATI 304L page gives a narrower chromium range of 17.5 to 19.5 percent, in weight percent. No melting or process route for the alloy was found on the pages fetched.",
      "parts": [
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "The matrix of the alloy.",
          "share_note": "balance"
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "Gives the stainless corrosion resistance. The 18-8 family is named for about 18 percent chromium (ATI). ATI prints 17.5 to 19.5 for the same grade.",
          "share_percent": 18,
          "share_high": 20
        },
        {
          "name": "Nickel",
          "symbol": "Ni",
          "role": "With chromium, makes the 18-8 austenitic family (ATI).",
          "share_percent": 8,
          "share_high": 12
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Maximum 0.030 percent. Kept low so that chromium carbide does not form at grain boundaries after welding.",
          "share_percent": 0,
          "share_high": 0.03
        },
        {
          "name": "Manganese",
          "symbol": "Mn",
          "role": "Maximum 2.00 percent. Impurity and processing element held to a maximum.",
          "share_percent": 0,
          "share_high": 2
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Maximum 0.75 percent.",
          "share_percent": 0,
          "share_high": 0.75
        },
        {
          "name": "Phosphorus",
          "symbol": "P",
          "role": "Maximum 0.045 percent. Impurity held low.",
          "share_percent": 0,
          "share_high": 0.045
        },
        {
          "name": "Sulfur",
          "symbol": "S",
          "role": "Maximum 0.030 percent. Impurity held low.",
          "share_percent": 0,
          "share_high": 0.03
        },
        {
          "name": "Nitrogen",
          "symbol": "N",
          "role": "Maximum 0.10 percent.",
          "share_percent": 0,
          "share_high": 0.1
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet with a GHS classification for the 304L alloy was fetched. The PubChem records below are for elemental nickel and chromium.",
        "points": [
          {
            "label": "Nickel",
            "line": "PubChem lists elemental nickel as Danger: H317 (skin sensitiser), H351 (suspected carcinogen) and H372 (organ damage on repeated exposure)."
          },
          {
            "label": "Chromium",
            "line": "PubChem lists elemental chromium with H317, H319 and H334 in notifications that carry hazard codes. Half of the 2,404 reports say it does not meet GHS criteria."
          },
          {
            "label": "Cutting and welding",
            "line": "Cutting, grinding and welding stainless steel can release metal fume and dust. No fume source was fetched, so check the supplier safety data sheet before work."
          }
        ],
        "level": 1,
        "verdict": "Element data only, no alloy record"
      },
      {
        "title": "Welding and heat",
        "lead": "Sensitization is the main fabrication risk, and the low carbon of 304L is there to limit it.",
        "points": [
          {
            "label": "Range",
            "line": "Holding or slow cooling between 450 and 900 C precipitates chromium carbide at grain boundaries (Thermal Processing). Wikipedia gives 480 to 820 C."
          },
          {
            "label": "Fix",
            "line": "The carbon limit is 0.030 percent maximum. Carpenter says this minimises carbide precipitation during welding."
          },
          {
            "label": "Severe service",
            "line": "For the most severe environments, Carpenter advises reannealing the welded structure."
          }
        ],
        "level": 2,
        "verdict": "Low carbon limits sensitization"
      },
      {
        "title": "In sea water",
        "lead": "Chloride is the watch point. Carpenter rates 304 and 304L restricted in sea water on its comparative scale.",
        "points": [
          {
            "label": "Sea water",
            "line": "Carpenter's comparative scale rates sea water as Restricted and recommends corrosion testing."
          },
          {
            "label": "Chloride",
            "line": "Wikipedia says 304, which it describes as having the same corrosion resistance as 304L, is subject to pitting and crevice corrosion in warm chloride and to stress corrosion cracking above about 60 C."
          }
        ],
        "level": 3,
        "verdict": "Restricted in sea water"
      }
    ]
  },
  "updated": "2026-10-24",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 26,
    "unreachable": 0,
    "caveats": 6,
    "note": "Written by an AI assistant on 2026-10-24 from pages fetched that day. Web search was unavailable, so datasheet pages were fetched directly with curl. The physical properties come from the ATI 302/304/304L/305 table and the CarTech 304/304L sheet, which are shared with other grades. The UPMET 304L values come from a column on an Alloy 304 sheet."
  },
  "sources": {
    "ati-304l": {
      "title": "ATI 304L Austenitic Stainless Steel, UNS S30403 (product page)",
      "id": "ATI product page, 304L",
      "url": "https://atimaterials.com/Products/ati-304l",
      "kind": "datasheet",
      "license": "ATI web page (cited, not reproduced)"
    },
    "ati-tds-304l": {
      "title": "ATI 302, 304, 304L and 305 Technical Data Sheet (version 1, 2014)",
      "id": "ATI TDS, version 1 (2/17/2014)",
      "url": "https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_302_304_304l_305_tds_en3_v1.pdf",
      "year": 2014,
      "kind": "datasheet",
      "license": "supplier data sheet (cited, not reproduced)"
    },
    "icast-s30403": {
      "title": "ICAST Alloys: ASTM A240 UNS S30403 data sheet, chemical composition, mechanical properties and cross reference",
      "id": "ASTM A240 UNS S30403",
      "url": "https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S30403.pdf",
      "kind": "datasheet",
      "license": "stockist data sheet (cited, not reproduced)"
    },
    "carpenter-304l": {
      "title": "Carpenter Technology: 304L alloy page (type analysis, applicable specifications)",
      "id": "304L alloy finder page",
      "url": "https://www.carpentertechnology.com/alloy-finder/304L",
      "kind": "datasheet",
      "license": "manufacturer web page (cited, not reproduced)"
    },
    "carpenter-304-304l-datasheet": {
      "title": "CarTech 304/304L Stainless data sheet (Carpenter Technology, combined 304 and 304L)",
      "id": "CarTech 304/304L Stainless, edition date 07/01/2000, copyright 2020",
      "url": "https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/304L.pdf",
      "kind": "datasheet",
      "license": "manufacturer data sheet (cited, not reproduced)"
    },
    "upmet-304-304l": {
      "title": "UPMET datasheet: Alloy 304 Stainless Steel Sheet, Coil and Plate (AMS 5511, 5513), with a 304L mechanical column",
      "id": "UNS S30400, AMS 5513",
      "url": "https://www.upmet.com/sites/default/files/datasheets/304-304l.pdf",
      "year": 2026,
      "kind": "datasheet",
      "license": "supplier data sheet (cited, not reproduced)"
    },
    "alleima-list": {
      "title": "Alleima: list of alloys (billets and blooms), grade table with UNS, ASTM and EN steel numbers",
      "id": "Alleima list of alloys",
      "url": "https://www.alleima.com/cz/products/billets-and-blooms/list-of-alloys",
      "kind": "datasheet",
      "license": "web page (cited, not reproduced)"
    },
    "alloys-intl-304l": {
      "title": "Alloys International: stainless steel 304L page (W.Nr and EN names)",
      "id": "stainless_steel304L page",
      "url": "https://alloysintl.com/inventory/stainless-steel/stainless_steel304L/",
      "kind": "datasheet",
      "license": "stockist web page (cited, not reproduced)"
    },
    "wiki-304": {
      "title": "Wikipedia: 304 stainless steel (carbon content, applications, corrosion resistance)",
      "id": "304 stainless steel",
      "url": "https://en.wikipedia.org/wiki/304_stainless_steel",
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "thermal-processing": {
      "title": "Thermal Processing: Intergranular Corrosion of Austenitic Stainless Steels",
      "id": "thermalprocessing.com",
      "url": "https://thermalprocessing.com/intergranular-corrosion-of-austenitic-stainless-steels/",
      "kind": "web",
      "license": "web page (cited, not reproduced)"
    },
    "nist-vacuum-2020": {
      "title": "Fedchak et al.: Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments",
      "id": "arXiv:2009.10560 (DOI 10.1116/6.0000657)",
      "url": "https://arxiv.org/pdf/2009.10560",
      "year": 2020,
      "kind": "paper",
      "license": "arXiv preprint (cited, not reproduced)"
    },
    "usgs-nickel-2026": {
      "title": "USGS Mineral Commodity Summaries 2026: Nickel",
      "id": "mcs2026-nickel",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "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-crit-2025": {
      "title": "USGS: About the 2025 List of Critical Minerals",
      "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)"
    },
    "pubchem-nickel": {
      "title": "PubChem: Nickel (CID 935), Safety and Hazards, GHS Classification",
      "id": "CID 935",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/935",
      "kind": "database",
      "license": "PubChem terms (public)"
    },
    "pubchem-chromium": {
      "title": "PubChem: Chromium (CID 23976), Safety and Hazards, GHS Classification",
      "id": "CID 23976",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23976",
      "kind": "database",
      "license": "PubChem terms (public)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/stainless-304l/"
}