{ "spore": "profile", "id": "steel-4140", "spore_version": "0.2", "family": "carbon-and-alloy-steels", "name": "Alloy steel AISI 4140 (chromium-molybdenum)", "abbreviation": "4140 (UNS G41400)", "role": "structural alloy", "category": "metals", "type": "steels-and-stainless", "summary": "AISI 4140 is a medium-carbon chromium-molybdenum alloy steel (UNS G41400) whose strength depends on heat treatment. Quenched and tempered bar of 10 to 100 mm reaches a minimum yield strength of 740 MPa. In hydrogen gas and in dilute sulfuric acid its strength and corrosion resistance suffer, which limits use where those are present.", "best_for": "Machine parts and structures in medium and large sections that need high strength and toughness after quenching and tempering", "weakest_at": "Hydrogen gas, which cut notched strength by about 60 percent in one room-temperature study, and dilute sulfuric acid, which corroded it at 176.87 mpy", "identity": { "formula": "Fe balance; 0.38 to 0.43 C, 0.75 to 1.00 Mn, 0.15 to 0.35 Si, 0.80 to 1.10 Cr, 0.15 to 0.25 Mo, 0.035 max P, 0.040 max S (wt%, ASTM A29 limits as printed in Table 1.1.1 of the Sandia reference)", "designations": [ { "system": "AISI", "code": "4140", "source": "voestalpine-4140", "where": "NEAREST STANDARDS table, AISI column" }, { "system": "UNS", "code": "G41400", "source": "voestalpine-4140", "where": "NEAREST STANDARDS table, UNS column" }, { "system": "EN", "code": "1.7225", "source": "saky-4140", "where": "Product description: 1.7225 is the European EN standard" }, { "system": "EN name", "code": "42CrMo4", "source": "metinvest-42crmo4", "where": "Steel 42CrMo4 analogues table, EU column" }, { "system": "ISO", "code": "683-2", "source": "metinvest-42crmo4", "where": "42CrMo4 page: made in accordance with DIN EN ISO 683-2 (formerly EN 10083-3)" }, { "system": "JIS", "code": "SCM440", "source": "elgin-4140", "where": "Key Words line" }, { "system": "JIS", "code": "SCM 4", "source": "elgin-4140", "where": "Key Words line, printed as JIS SCM 4" }, { "system": "SAE", "code": "4140", "source": "saky-4140", "where": "Short Description: AISI SAE 4140 alloy steel" }, { "system": "SAE", "code": "J404", "source": "elgin-4140", "where": "Key Words line" }, { "system": "SAE", "code": "J412", "source": "elgin-4140", "where": "Key Words line" }, { "system": "SAE", "code": "J770", "source": "elgin-4140", "where": "Key Words line" }, { "system": "ASTM", "code": "A29", "source": "saky-4140", "where": "Specifications table, Standard row" }, { "system": "ASTM", "code": "A322", "source": "elgin-4140", "where": "Key Words line" }, { "system": "ASTM", "code": "A331", "source": "elgin-4140", "where": "Key Words line" }, { "system": "ASTM", "code": "A505", "source": "elgin-4140", "where": "Key Words line" }, { "system": "ASTM", "code": "A519", "source": "elgin-4140", "where": "Key Words line" }, { "system": "ASTM", "code": "A646", "source": "elgin-4140", "where": "Key Words line" }, { "system": "BS", "code": "EN19", "source": "tachart-709m40", "where": "709M40 page, Alias list, printed En19" }, { "system": "BS", "code": "708M40", "source": "elgin-4140", "where": "Key Words line, printed B.S. 708 M 40 (UK)" }, { "system": "BS", "code": "708A42", "source": "elgin-4140", "where": "Key Words line, printed B.S. 708 A 42 (UK)" }, { "system": "BS", "code": "709M40", "source": "elgin-4140", "where": "Key Words line, printed B.S. 709 M 40 (UK)" }, { "system": "DTD", "code": "167A", "source": "tachart-709m40", "where": "709M40 page, Alias list" }, { "system": "AFNOR", "code": "40 CD 4", "source": "elgin-4140", "where": "Key Words line" }, { "system": "AFNOR", "code": "42 CD 4", "source": "elgin-4140", "where": "Key Words line, printed AFNOR 42 CD 4 (France)" }, { "system": "SS", "code": "14 2244", "source": "elgin-4140", "where": "Key Words line, printed SS14 2244 (Sweden)" }, { "system": "MIL", "code": "MIL-S-16974", "source": "elgin-4140", "where": "Key Words line, printed MIL SPEC MIL-S-16974" }, { "system": "MIL", "code": "S 5626", "source": "aircraft-4140", "where": "Specifications list, MIL S 5626" }, { "system": "AMS", "code": "S 5626", "source": "aircraft-4140", "where": "Specifications list, AMS S 5626" }, { "system": "AMS", "code": "6349", "source": "aircraft-4140", "where": "Specifications list, AMS 6349" }, { "system": "AMS", "code": "6382", "source": "aircraft-4140", "where": "Specifications list, AMS 6382" }, { "system": "AMS", "code": "6381", "source": "elgin-4140", "where": "Key Words line" }, { "system": "AMS", "code": "6390", "source": "elgin-4140", "where": "Key Words line" }, { "system": "AMS", "code": "6395", "source": "elgin-4140", "where": "Key Words line" }, { "system": "AS", "code": "1444-1996", "source": "aircraft-4140", "where": "Specifications list, AS 1444-1996" }, { "system": "IS", "code": "40Cr1Mo28", "source": "elgin-4140", "where": "Key Words line, printed IS 1570, IS 4367 and IS 5517 40Cr1Mo28" }, { "system": "DIN", "code": "41CrMo4", "note": "nearest equivalent", "source": "voestalpine-4140", "where": "NEAREST STANDARDS table, DIN column, printed as 41CrMo4" }, { "system": "BS", "code": "EN19A", "note": "nearest equivalent", "source": "voestalpine-4140", "where": "NEAREST STANDARDS table, BS column" } ], "source": "sandia-1211", "where": "Table 1.1.1, Allowable composition ranges (wt%) for Cr-Mo steels, row 4140" }, "tags": { "environments": [], "stresses": [], "applications": [ "mechanisms", "structures" ] }, "properties": [ { "benchmark": "yield_strength", "label": "Yield strength, quenched and tempered, 10 to 100 mm", "value": 740, "bound": "lower", "unit": "MPa", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "10 to 100 mm", "strength_type": "Rp0.2, minimum", "unit_in_source": "N/mm2" }, "method": "Mechanical properties (heat treated) table, minimum as printed; N/mm2 is the same number as MPa", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Yield Strength (Rp 0.2), 10-100 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "yield_strength", "label": "Yield strength, quenched and tempered, 101 to 250 mm", "value": 665, "bound": "lower", "unit": "MPa", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "101 to 250 mm", "strength_type": "Rp0.2, minimum", "unit_in_source": "N/mm2" }, "method": "Mechanical properties (heat treated) table, minimum as printed; N/mm2 is the same number as MPa", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Yield Strength (Rp 0.2), 101-250 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, quenched and tempered, 10 to 100 mm", "value": 930, "value_high": 1080, "bound": "range", "unit": "MPa", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "10 to 100 mm", "unit_in_source": "N/mm2" }, "method": "Mechanical properties (heat treated) table, minimum and maximum as printed; N/mm2 is the same number as MPa", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Tensile (Rm), 10-100 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, quenched and tempered, 101 to 250 mm", "value": 850, "value_high": 1000, "bound": "range", "unit": "MPa", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "101 to 250 mm", "unit_in_source": "N/mm2" }, "method": "Mechanical properties (heat treated) table, minimum and maximum as printed; N/mm2 is the same number as MPa", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Tensile (Rm), 101-250 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "elongation", "label": "Elongation, quenched and tempered, 10 to 100 mm", "value": 12, "bound": "lower", "unit": "%", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "10 to 100 mm", "gauge": "A5 as labelled in the datasheet" }, "method": "Mechanical properties (heat treated) table, minimum as printed", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Elongation (A5 %), 10-100 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "impact_energy", "label": "Charpy impact energy, quenched and tempered, 10 to 100 mm", "value": 42, "bound": "lower", "unit": "J", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "10 to 100 mm", "test": "Charpy", "test_temperature": "not stated in the datasheet" }, "method": "Mechanical properties (heat treated) table, minimum as printed", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Charpy Impact (J), 10-100 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "hardness_brinell", "label": "Hardness, quenched and tempered, 10 to 100 mm", "value": 269, "value_high": 331, "bound": "range", "unit": "HB", "scope": "material", "conditions": { "condition": "quenched and tempered: oil quench from 830 to 860 C, temper 540 to 680 C for at least 1 h, air cool", "section": "10 to 100 mm" }, "method": "Mechanical properties (heat treated) table, range as printed", "status": "ground", "source": "voestalpine-4140", "where": "Mechanical Properties (heat treated) table, Hardness (HB), 10-100 mm column", "source_detail": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "yield_strength", "label": "Yield strength, typical, 50 mm section", "value": 770, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "50 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 50 mm; typical values, not minimums", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, row Alloy 4140, section 50 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "yield_strength", "label": "Yield strength, typical, 200 mm section", "value": 570, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "200 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 200 mm; typical values, not minimums", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, row Alloy 4140, section 200 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, typical, 50 mm section", "value": 930, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "50 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 50 mm; typical values, not minimums", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, row Alloy 4140, section 50 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, typical, 200 mm section", "value": 850, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "200 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 200 mm; typical values, not minimums", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, row Alloy 4140, section 200 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "elongation", "label": "Elongation, typical, 50 mm section", "value": 17, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "50 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 50 mm", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, Elongation %, row Alloy 4140, section 50 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "impact_energy", "label": "Izod impact energy, typical, 50 mm section", "value": 90, "bound": "exact", "unit": "J", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "50 mm", "test": "Izod" }, "method": "Typical mechanical properties table as printed (column headed Izod J)", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, Izod J, row Alloy 4140, section 50 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "hardness_brinell", "label": "Hardness, typical, 50 mm section", "value": 275, "bound": "exact", "unit": "HB", "scope": "material", "conditions": { "condition": "hardened and tempered, supplied to condition T (the temper temperature is not stated)", "section": "50 mm" }, "method": "Typical mechanical properties table as printed, row Alloy 4140 at 50 mm", "status": "ground", "source": "aircraft-4140", "where": "Typical Mechanical Properties table, Hardness HB, row Alloy 4140, section 50 mm", "source_detail": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, normalised at 870 C", "value": 1020, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "normalised at 870 C, air cooled", "section": "25 mm (1 in.) round" }, "method": "Mechanical properties table of the fact sheet, value as printed for the stated condition", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Tensile Strength Ultimate, row 1020 MPa (heading: normalized at 870 C, 25 mm round)", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "yield_strength", "label": "Yield strength, normalised at 870 C", "value": 655, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "condition": "normalised at 870 C, air cooled", "section": "25 mm (1 in.) round" }, "method": "Mechanical properties table of the fact sheet, value as printed for the stated condition", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Tensile Strength Yield, row 655 MPa (heading: normalized at 870 C, 25 mm round)", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "elongation", "label": "Elongation, normalised at 870 C", "value": 17.7, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "condition": "normalised at 870 C, air cooled", "section": "25 mm (1 in.) round", "gauge": "50 mm" }, "method": "Mechanical properties table of the fact sheet, value as printed for the stated condition", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Elongation at Break, row 17.70% in 50 mm", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "reduction_of_area", "label": "Reduction of area, normalised at 870 C", "value": 46.8, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "condition": "normalised at 870 C, air cooled", "section": "25 mm (1 in.) round" }, "method": "Mechanical properties table of the fact sheet, value as printed for the stated condition", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Reduction of Area, row 46.80%", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "hardness_brinell", "label": "Hardness, Brinell, normalised at 870 C", "value": 302, "bound": "exact", "unit": "HB", "scope": "material", "conditions": { "condition": "normalised at 870 C, air cooled", "section": "25 mm (1 in.) round" }, "method": "Mechanical properties table of the fact sheet; the Brinell value is printed and the other scales are converted by the datasheet", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Hardness Brinell, row 302", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "density", "value": 7.85, "bound": "exact", "unit": "g/cc", "scope": "material", "conditions": { "basis": "physical properties table; no temperature or heat treatment stated" }, "method": "Physical properties table as printed (metric column)", "status": "ground", "source": "elgin-4140", "where": "Physical Properties, Density, row 7.85 g/cc", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "elastic_modulus", "label": "Modulus of elasticity", "value": 205, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "basis": "datasheet comment Typical for steel; no temperature or heat treatment stated" }, "method": "Mechanical properties table as printed; the datasheet marks the value as typical for steel", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Modulus of Elasticity, row 205 GPa", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "shear_modulus", "value": 80, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "basis": "datasheet comment Typical for steel; no temperature or heat treatment stated" }, "method": "Mechanical properties table as printed; the datasheet marks the value as typical for steel", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Shear Modulus, row 80.0 GPa", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "bulk_modulus", "value": 160, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "basis": "datasheet comment Typical for steel; no temperature or heat treatment stated" }, "method": "Mechanical properties table as printed; the datasheet marks the value as typical for steel", "status": "ground", "source": "elgin-4140", "where": "Mechanical Properties, Bulk Modulus, row 160 GPa", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "poissons_ratio", "value": 0.29, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "basis": "datasheet marks the value as calculated; no temperature stated" }, "method": "Mechanical properties table as printed; the datasheet notes the value is calculated", "status": "calculated", "source": "elgin-4140", "where": "Mechanical Properties, Poissons Ratio, row 0.29 (comment Calculated)", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of thermal expansion, 0 to 100 C", "value": 12.2, "bound": "exact", "unit": "ppm/K", "scope": "material", "conditions": { "temperature": "0 to 100 C (32 to 212 F)", "unit_in_source": "µm/m-°C, numerically the same as ppm/K" }, "method": "Thermal properties table as printed; the unit is the same number as ppm/K", "status": "ground", "source": "elgin-4140", "where": "Thermal Properties, CTE linear, row 12.2 µm/m-°C at 0.000 to 100 °C", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of thermal expansion, 20 to 600 C", "value": 14.6, "bound": "exact", "unit": "ppm/K", "scope": "material", "conditions": { "temperature": "20 to 600 C (68 to 1110 F)", "unit_in_source": "µm/m-°C, numerically the same as ppm/K" }, "method": "Thermal properties table as printed; the unit is the same number as ppm/K", "status": "ground", "source": "elgin-4140", "where": "Thermal Properties, CTE linear, row 14.6 µm/m-°C at 20.0 to 600 °C", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "specific_heat", "value": 0.473, "bound": "exact", "unit": "J/gK", "scope": "material", "conditions": { "temperature": "150 to 200 C (302 to 392 F)", "unit_in_source": "J/g-°C" }, "method": "Thermal properties table as printed; J/g-°C is the same number as J/gK", "status": "ground", "source": "elgin-4140", "where": "Thermal Properties, Specific Heat Capacity, row 0.473 J/g-°C at 150 to 200 °C", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "thermal_conductivity", "value": 42.6, "bound": "exact", "unit": "W/mK", "scope": "material", "conditions": { "temperature": "100 C (212 F)", "unit_in_source": "W/m-K, with the W lost in text extraction; the BTU column on the same row (296 BTU-in/hr-ft2-F) confirms W/m-K" }, "method": "Thermal properties table as printed; unit inferred from the BTU-in column on the same row", "status": "ground", "source": "elgin-4140", "where": "Thermal Properties, Thermal Conductivity, row 42.6 at 100 C (296 BTU-in/hr-ft2-F)", "source_detail": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" } }, { "benchmark": "yield_strength", "label": "Yield strength, high-strength condition, smooth bar", "value": 1235, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa helium gas", "test": "smooth tensile, room temperature, strain rate 3.3e-5 per s", "yield_definition": "deviation from linearity on load vs time plot" }, "method": "Table 3.1.1.1 row 4140 (69 MPa He); the same value appears in Table 1.1.3 high-strength row; kelvin converted to C by subtracting 273.15 and rounding", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa He; Table 1.1.3, 4140 high strength row", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, high-strength condition, helium", "value": 1283, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa helium gas", "test": "smooth tensile, room temperature" }, "method": "Table 3.1.1.1 row 4140, 69 MPa He", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa He, Su column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, high-strength condition, hydrogen", "value": 1228, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa hydrogen gas", "test": "smooth tensile, room temperature" }, "method": "Table 3.1.1.1 row 4140, 69 MPa H2", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa H2, Su column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "reduction_of_area", "label": "Reduction of area, high-strength condition, helium", "value": 48, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa helium gas", "test": "smooth tensile, room temperature" }, "method": "Table 3.1.1.1 row 4140, 69 MPa He, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa He, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "reduction_of_area", "label": "Reduction of area, high-strength condition, hydrogen", "value": 8.8, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa hydrogen gas", "test": "smooth tensile, room temperature" }, "method": "Table 3.1.1.1 row 4140, 69 MPa H2, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa H2, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "elongation", "label": "Elongation, high-strength condition, hydrogen", "value": 2.6, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, water quench, T 755 K/120 min (A 843 C 1 h, water quench, temper 482 C 2 h); strength level high", "environment": "69 MPa hydrogen gas", "test": "smooth tensile, room temperature" }, "method": "Table 3.1.1.1 row 4140, 69 MPa H2, Elt column; the footnote for a 32 mm gauge is printed against the helium value, not this one", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.1.1, 4140 row, 69 MPa H2, Elt column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "yield_strength", "label": "Yield strength, low-strength condition", "value": 642, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, oil quench, T 977 K/120 min, air cool (A 843 C 1 h, oil quench, temper 704 C 2 h, air cool); strength level low", "environment": "not stated for the smooth yield value" }, "method": "Table 1.1.3 low-strength 4140 row; kelvin converted to C by subtracting 273.15 and rounding; the same Sy* is listed in Table 3.1.2.1", "status": "ground", "source": "sandia-1211", "where": "Table 1.1.3, 4140 low strength row, Sy column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, low-strength condition", "value": 745, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, oil quench, T 977 K/120 min, air cool (A 843 C 1 h, oil quench, temper 704 C 2 h, air cool); strength level low", "environment": "not stated in Table 1.1.3" }, "method": "Table 1.1.3 low-strength 4140 row", "status": "ground", "source": "sandia-1211", "where": "Table 1.1.3, 4140 low strength row, Su column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "reduction_of_area", "label": "Reduction of area, low-strength condition", "value": 68, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 1116 K/60 min, oil quench, T 977 K/120 min, air cool (A 843 C 1 h, oil quench, temper 704 C 2 h, air cool); strength level low", "environment": "not stated in Table 1.1.3" }, "method": "Table 1.1.3 low-strength 4140 row", "status": "ground", "source": "sandia-1211", "where": "Table 1.1.3, 4140 low strength row, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_tensile_strength", "label": "Notched tensile strength, low-strength condition, air", "value": 1345, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "air", "specimen": "V-notch, 60 degree included angle, notch root radius 0.024 mm, Kt 8.4", "displacement_rate": "about 4e-4 mm/s" }, "method": "Table 3.1.2.1 row 4140 (low strength), air", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, air, sigma s column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_tensile_strength", "label": "Notched tensile strength, low-strength condition, helium", "value": 1259, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "69 MPa helium gas", "specimen": "V-notch, 60 degree included angle, notch root radius 0.024 mm, Kt 8.4", "displacement_rate": "about 4e-4 mm/s" }, "method": "Table 3.1.2.1 row 4140 (low strength), 69 MPa He", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, 69 MPa He, sigma s column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_tensile_strength", "label": "Notched tensile strength, low-strength condition, hydrogen", "value": 1074, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "69 MPa hydrogen gas", "specimen": "V-notch, 60 degree included angle, notch root radius 0.024 mm, Kt 8.4", "displacement_rate": "about 4e-4 mm/s" }, "method": "Table 3.1.2.1 row 4140 (low strength), 69 MPa H2", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, 69 MPa H2, sigma s column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_tensile_strength", "label": "Notched tensile strength, high-strength condition, helium", "value": 2160, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, water quench, temper 482 C 2 h; strength level high", "environment": "69 MPa helium gas", "specimen": "V-notch, 60 degree included angle, notch root radius 0.024 mm, Kt 8.4", "displacement_rate": "about 4e-4 mm/s" }, "method": "Table 3.1.2.1 row 4140 (high strength), 69 MPa He", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 high strength row, 69 MPa He, sigma s column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_tensile_strength", "label": "Notched tensile strength, high-strength condition, hydrogen", "value": 862, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, water quench, temper 482 C 2 h; strength level high", "environment": "69 MPa hydrogen gas", "specimen": "V-notch, 60 degree included angle, notch root radius 0.024 mm, Kt 8.4", "displacement_rate": "about 4e-4 mm/s" }, "method": "Table 3.1.2.1 row 4140 (high strength), 69 MPa H2", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 high strength row, 69 MPa H2, sigma s column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_reduction_of_area", "label": "Notched reduction of area, low-strength condition, air", "value": 10, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "air", "specimen": "V-notch, Kt 8.4" }, "method": "Table 3.1.2.1 row 4140 (low strength), air, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, air, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_reduction_of_area", "label": "Notched reduction of area, low-strength condition, helium", "value": 14, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "69 MPa helium gas", "specimen": "V-notch, Kt 8.4" }, "method": "Table 3.1.2.1 row 4140 (low strength), 69 MPa He, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, 69 MPa He, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_reduction_of_area", "label": "Notched reduction of area, low-strength condition, hydrogen", "value": 7.1, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, oil quench, temper 704 C 2 h, air cool; strength level low", "environment": "69 MPa hydrogen gas", "specimen": "V-notch, Kt 8.4" }, "method": "Table 3.1.2.1 row 4140 (low strength), 69 MPa H2, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 low strength row, 69 MPa H2, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_reduction_of_area", "label": "Notched reduction of area, high-strength condition, helium", "value": 2.8, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, water quench, temper 482 C 2 h; strength level high", "environment": "69 MPa helium gas", "specimen": "V-notch, Kt 8.4" }, "method": "Table 3.1.2.1 row 4140 (high strength), 69 MPa He, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 high strength row, 69 MPa He, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } }, { "benchmark": "notched_reduction_of_area", "label": "Notched reduction of area, high-strength condition, hydrogen", "value": 0.9, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "heat_treatment": "A 843 C 1 h, water quench, temper 482 C 2 h; strength level high", "environment": "69 MPa hydrogen gas", "specimen": "V-notch, Kt 8.4" }, "method": "Table 3.1.2.1 row 4140 (high strength), 69 MPa H2, RA column", "status": "ground", "source": "sandia-1211", "where": "Table 3.1.2.1, 4140 high strength row, 69 MPa H2, RA column", "source_detail": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" } } ], "corrosion": [ { "environment": "Immersion in 0.5 M sulfuric acid (H2SO4), 48 to 144 h, weight-loss test", "headline": "AISI 4140 corroded at 132.65 to 176.87 mpy in 0.5 M sulfuric acid, and its rate rose with exposure time.", "effect": "Rates were 132.65 mpy at 48 h, 143.7 mpy at 96 h and 176.87 mpy at 144 h, from weight loss (Table 1). The paper reports obvious rust on all AISI 4140 specimens at every time and XRD shows metal oxides as the corrosion products. Only AISI 1045 corroded faster, at 183.7 mpy at 144 h. The severe rating is an assistant judgement from the mpy values, not a rating in the paper.", "rating": "severe", "conditions": { "solution": "0.5 M H2SO4", "exposure_times_h": "48, 96, 144", "specimen": "25 mm diameter by 30 mm high, three per material (as printed)", "heat_treatment": "not stated in the paper", "method": "weight loss in mg; corrosion rate in mpy" }, "source": "itats-2021", "where": "Table 1 (AISI 4140 rows); Results, Corrosion Rate; Macrostructure results" }, { "environment": "Hydrogen gas at 69 MPa, room temperature (one study compiled by Sandia)", "headline": "Hydrogen gas at 69 MPa cuts the notched tensile strength of high-strength 4140 from 2160 to 862 MPa, and its notched reduction of area from 2.8 to 0.9 percent.", "effect": "The Sandia reference says hydrogen severely degrades reduction of area in smooth tension (80% lower than in helium), while ultimate strength barely changes (1283 to 1228 MPa). Hydrogen lowers notched tensile strength by about 60% for high-strength 4140 and by about 15% for low-strength 4140. The yield strength of 4140 sets how severe the loss is, so the high-strength condition suffers most.", "rating": "severe", "conditions": { "environment": "69 MPa hydrogen gas, room temperature", "comparison": "69 MPa helium gas", "notch": "V-notch, Kt 8.4", "heat_treatment_high": "A 843 C 1 h, water quench, temper 482 C 2 h", "heat_treatment_low": "A 843 C 1 h, oil quench, temper 704 C 2 h" }, "source": "sandia-1211", "where": "Sections 3.1.1 and 3.1.2 (text); Tables 3.1.1.1 and 3.1.2.1" } ], "risks": { "hazards": [ { "text": "PubChem aggregated GHS for elemental chromium (signal word Danger): H317 (20.7%), H319 (19.1%) and H334 (20.3%) are the reported codes above 10%; H335, H320, H341, H371, H400 and H410 also appear in notifications. About half of 2404 company reports (1202) say it does not meet GHS criteria. The data cover the element, not the alloy.", "ghs": [ "H317", "H319", "H334", "H335", "H320", "H341", "H371", "H400", "H410" ], "source": "pubchem-chromium", "where": "Safety and Hazards, GHS Classification (CID 23976)" }, { "text": "PubChem aggregated GHS for elemental molybdenum: 57.4% (874 of 1523) of reports say it does not meet GHS criteria. Reported codes include H228 flammable solid (30%), H361 suspected of damaging fertility or the unborn child (29.5%), H225 (11.6%), H315, H319 and H335. The data cover the element, not the alloy.", "ghs": [ "H228", "H361", "H225", "H315", "H319", "H335" ], "source": "pubchem-molybdenum", "where": "Safety and Hazards, GHS Classification (CID 23932)" } ], "failure_risks": [ { "mode": "Hydrogen embrittlement in gaseous hydrogen", "trigger": "Hydrogen gas at 69 MPa, room temperature, notched and smooth specimens", "consequence": "Notched tensile strength of high-strength 4140 fell from 2160 to 862 MPa, and its notched reduction of area from 2.8 to 0.9 percent. The source ties the loss to yield strength.", "severity": "high", "source": "sandia-1211", "where": "Table 3.1.2.1; Section 3.1.2" }, { "mode": "Acid corrosion with weight loss", "trigger": "Immersion in 0.5 M sulfuric acid for 48 to 144 h", "consequence": "Mass fell from 4000 mg to 1600 mg after 144 h, a corrosion rate of 176.87 mpy, with visible rust on the specimens.", "severity": "high", "source": "itats-2021", "where": "Table 1, AISI 4140 rows" }, { "mode": "Temper brittleness", "trigger": "Tempering in the 200 to 420 C range", "consequence": "Brittleness. The supplier says this tempering range should be avoided.", "severity": "moderate", "source": "aircraft-4140", "where": "Heat Treatments, Tempering note" } ], "side_effects": [], "handling": [ { "text": "Harden at 830 to 860 C and oil quench, then temper at 540 to 680 C for at least 1 hour and air cool (recommended for the quenched and tempered condition).", "source": "voestalpine-4140", "where": "Heat Treatment (recommended), Harden and Temper rows" }, { "text": "Stress relieve about 30 to 50 C below the tempering temperature for the quenched and tempered condition, or at 600 to 650 C for the annealed condition, then air cool.", "source": "voestalpine-4140", "where": "Heat Treatment (recommended), Stress Relieve row" }, { "text": "Avoid tempering between 200 and 420 C; the supplier says this causes temper brittleness.", "source": "aircraft-4140", "where": "Heat Treatments, Tempering note" } ], "mitigations": [ { "text": "The source ties the hydrogen damage to yield strength. In the room-temperature study the lower-strength 4140 lost about 15% of its notched tensile strength, against about 60% for the high-strength condition, so keep the yield strength of the chosen condition in view wherever hydrogen may be present.", "source": "sandia-1211", "where": "Section 3.1.2 (text); Table 3.1.2.1" }, { "text": "Molybdenum in the grade prevents temper brittleness, per the supplier; keep the Mo content within the datasheet limits.", "source": "voestalpine-4140", "where": "Description" } ] }, "uses": [ { "application": "mechanisms", "device": "Axles, gears, shafts, spindles, pinions, sprockets and studs", "example": "Aircraft Materials lists these among the other typical applications of alloy 4140 bar. No test data are given for them.", "source": "aircraft-4140", "where": "Description, other typical applications" }, { "application": "structures", "device": "Rams, crowbars and oil-patch and logging parts", "example": "The supplier calls alloy 4140 the most widely used alloy for oil-patch applications and lists logging parts and rams among its uses.", "source": "aircraft-4140", "where": "Description" }, { "application": "structures", "device": "Aerospace bar to AMS 6349 and AMS 6382", "example": "Alloy 4140 bar is supplied to AMS 6349 and AMS 6382, with AMS S 5626 and MIL S 5626 also listed. The Elgin fact sheet lists AMS 6381, 6382, 6390 and 6395.", "source": "aircraft-4140", "where": "Specifications list; Elgin keywords list" } ], "supply": [ { "subject": "Chromium", "abundance": "World resources are greater than 12 billion t of shipping-grade chromite, with 95% of world chromium resources in Kazakhstan and southern Africa. US net import reliance was 79% of apparent consumption in 2025 (estimated). US chromite imports in 2021 to 2024 came from South Africa (96%) and Turkey (3%).", "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": [ { "list": "USGS 2025 List of Critical Minerals (chromium, used in stainless steel)", "listed": true } ], "recycling": "Recycled chromium in stainless-steel scrap receipts was 21% of US apparent consumption in 2025.", "substitutes": [ "Chromium has no substitute in stainless steel, the leading end use, or in superalloys (USGS 2026)." ], "source": "usgs-chromium-2026", "where": "Salient Statistics; World Mine Production and Reserves (2025e; shares computed as printed tonnage over the 51,000 t world total); World Resources; Substitutes; Recycling" }, { "subject": "Molybdenum", "abundance": "World reserves were 17,000 thousand t (2025e). Identified resources are about 5.4 million t in the United States and about 20 million t in the rest of the world. Molybdenum is used principally as an alloying agent in cast iron, steel and superalloys. The Government of China imposed export controls on molybdenum powders in February 2025.", "producers": [ { "country": "China", "share_percent": 37.3, "year": 2025 }, { "country": "Chile", "share_percent": 16.2, "year": 2025 }, { "country": "United States", "share_percent": 15.4, "year": 2025 }, { "country": "Peru", "share_percent": 15, "year": 2025 }, { "country": "Mexico", "share_percent": 6.5, "year": 2025 } ], "critical_lists": [], "recycling": "Molybdenum is recycled in ferrous scrap, superalloy scrap and catalysts; USGS says recycled molybdenum may be as much as 30% of apparent supply.", "substitutes": [ "USGS: there is little substitution in steels; potential substitutes in alloy steels include boron, chromium, niobium (columbium) and vanadium." ], "source": "usgs-molybdenum-2026", "where": "Domestic Production and Use; Events, Trends and Issues; World Mine Production and Reserves (2025e; shares computed over the 260,000 t world total); World Resources; Substitutes; Recycling" } ], "media": [], "documents": [ { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet (Australia)", "type": "datasheet", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026 }, { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com)", "type": "datasheet", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf" }, { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "type": "datasheet", "url": "https://aircraftmaterials.com/data/alstst/4140.html" }, { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211), Sandia National Laboratories", "type": "report", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005 }, { "title": "Rosidah et al. 2021: The effect of time variation on the steels corrosion rate in 0.5 M H2SO4 solution (JMESI)", "type": "paper", "url": "https://ejournal.itats.ac.id/jmesi/article/download/2183/1989", "year": 2021 }, { "title": "USGS Mineral Commodity Summaries 2026: Chromium", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Molybdenum", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf", "year": 2026 }, { "title": "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: Chromium (CID 23976), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON/?heading=GHS+Classification", "year": 2026 }, { "title": "PubChem: Molybdenum (CID 23932), GHS classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON/?heading=GHS+Classification", "year": 2026 }, { "title": "Saky Steel: AISI 4140 1.7225 42CrMo4 SCM440 B7 Steel Bar (stockist page)", "type": "datasheet", "url": "https://www.sakysteel.com/aisi-4140-1-7225-42crmo4-scm440-b7-steel-bar.html" }, { "title": "Metinvest: Steel 42CrMo4 characteristics, properties and analogues (manufacturer page)", "type": "datasheet", "url": "https://metinvestholding.com/en/products/steel-grades/42crmo4" }, { "title": "Tachart: 709M40 grade page with alias list (stockist page)", "type": "datasheet", "url": "https://www.tachart.com/?p=1110" } ], "gaps": [ "No safety data sheet for AISI 4140 bar was read in this run. The hazard entries are PubChem records for elemental chromium and molybdenum. Welding, grinding and fume hazards of the steel itself are not sourced.", "Composition sources disagree. Elgin lists carbon as max 0.33 and manganese as 0.40 to 0.60; voestalpine gives maximum limits (carbon 0.40, manganese 1.00, silicon 0.40, chromium 1.10, molybdenum 0.30); Aircraft Materials gives single values (carbon 0.40, silicon 0.25, manganese 0.85, chromium 1.00, molybdenum 0.25). The recipe uses the ASTM A29 ranges printed in the Sandia reference; the other values are kept in their sources as printed.", "No annealed-condition strength value was found. Annealing temperatures also differ: voestalpine gives 680 to 720 C, and Aircraft Materials gives 830 to 850 C with furnace cooling.", "The Aircraft Materials typical rows do not state a temper temperature, so they are recorded as condition T with the temper temperature not stated.", "The hydrogen data come from one room-temperature study, compiled in the Sandia reference (its reference 4), at 69 MPa gas only. No temperature dependence, hydrogen concentration or cathodic-charging data were read. The Colombo 2020 paper (doi 10.1016/j.tafmec.2020.102810) returned a Cloudflare challenge, MDPI Materials 18(2), 339 returned Access Denied, and the arXiv 2012.10112 PDF was truncated.", "No chloride or salt-spray corrosion data for AISI 4140 were read. The Springer brake-disc paper (doi 10.1186/s44147-025-00702-z, NaCl immersion) returned an automated-access challenge. The only corrosion values here are in 0.5 M sulfuric acid, from a 2021 journal paper that does not state the heat treatment of its 4140 specimens.", "Mechanical values come from manufacturer datasheets, not from a standard such as AMS 6382 or ASTM A29. MatWeb and Total Materia were not reached in this run.", "Properties not in property-canon were given snake_case names: hardness_brinell, impact_energy, reduction_of_area, notched_tensile_strength and notched_reduction_of_area.", "Thermal conductivity: the W glyph was lost in text extraction. W/mK is inferred from the BTU-in column on the same row (296 BTU-in/hr-ft2-F matches 42.6 W/mK).", "Elgin's density, modulus, bulk and shear moduli, and Poisson's ratio carry no temperature or heat treatment; they are recorded as typical or calculated, as the datasheet marks them.", "Critical minerals: the USGS 2025 list page was read through a fetch summary, not raw text. Chromium is recorded as listed; the summary names no molybdenum entry, so molybdenum has no list entry. The EU critical raw materials list was not read.", "No flight, spacecraft or vacuum use of AISI 4140 was found in these sources. The uses are terrestrial machinery and aerospace specifications.", "Sandia's tables give temperatures in kelvin. The C values in the conditions are conversions (minus 273.15, rounded), and the printed kelvin values are kept beside them.", "The Sandia composition in Table 1.1.2 (0.40 C, 0.93 Cr, 0.20 Mo) is one test heat, not a specification, and it is not used in the recipe.", "Designations: no Aalco or Sandvik grade page was reached in this run; the web searches returned neither.", "Designations: voestalpine prints 41CrMo4 beside 1.7225 under DIN, while Metinvest and Saky print 42CrMo4 for 1.7225. Both are kept as printed; check the DIN name before relying on it.", "Designations: no source in this run calls 708M40, 709M40, 708A42 or EN19 a nearest equivalent, so they carry no note. Tachart lists AISI 4140 as an alias of its 709M40 page.", "Designations not added: SCM440H and the Russian grades 38XM and 40XFA appear only in the Metinvest 42CrMo4 analogues table. AISI 4137 and SAE 4137 are aliases of 709M40 on Tachart and are a different grade." ], "story": { "why": "AISI 4140 (UNS G41400) is a medium-carbon chromium-molybdenum steel. It is chosen for a balance of strength, toughness and wear resistance after quenching and tempering, and molybdenum keeps it free of temper brittleness, according to the supplier. Its strength depends on the condition: a normalised 25 mm bar, a quenched and tempered bar of 10 to 100 mm and a room-temperature hydrogen study each give different numbers, so every value in this profile carries its own condition. Its main weakness is hydrogen gas, which cut notched strength sharply in one room-temperature study.", "uses": [ { "where": "Gears, shafts and spindles", "line": "Aircraft Materials lists axles, gears, shafts, pump shafts, pinions, sprockets, studs and ring gears among the typical uses of alloy 4140 bar." }, { "where": "Oil-patch and logging parts", "line": "The same supplier calls alloy 4140 the most widely used alloy for oil-patch applications." }, { "where": "Aerospace bar", "line": "Alloy 4140 bar is supplied to the aerospace specifications AMS 6349 and AMS 6382 (Aircraft Materials)." } ], "can_do": [ { "label": "Strength", "line": "Quenched and tempered bar of 10 to 100 mm is specified at a minimum yield strength of 740 MPa and a tensile strength of 930 to 1080 MPa (voestalpine).", "scope": "material" }, { "label": "Toughness", "line": "In the same condition the minimum Charpy impact energy is 42 J (voestalpine).", "scope": "material" }, { "label": "Normalised", "line": "A 25 mm round normalised at 870 C gives 1020 MPa tensile strength, 655 MPa yield strength and 17.7% elongation (Elgin).", "scope": "material" }, { "label": "Stiffness", "line": "The modulus of elasticity is 205 GPa, typical for steel (Elgin).", "scope": "material" }, { "label": "Hydrogen", "line": "In 69 MPa hydrogen gas at room temperature, high-strength 4140 still reached 1228 MPa tensile strength, but its notched tensile strength fell to 862 MPa (Sandia).", "scope": "material" } ], "compare": "In the same 0.5 M sulfuric acid test, AISI 4140 corroded at a rate second only to AISI 1045 (176.87 mpy against 183.7 mpy at 144 h), while the stainless steel in the same test corroded least, because its chromium oxide film protects it (Rosidah et al., 2021). The fetched sources give no direct comparison with another grade on strength or hydrogen behaviour, so this paragraph is limited to that acid test.", "compare_rows": [ { "label": "Strength", "benchmark": "yield_strength", "scope": "material" }, { "label": "Stiffness", "benchmark": "elastic_modulus", "scope": "material" }, { "label": "Density", "benchmark": "density", "scope": "material" } ], "handling": [ "Quote the heat-treatment condition with every strength value, because the normalised, quenched and tempered, and hydrogen-tested rows differ.", "Avoid tempering between 200 and 420 C; the supplier says this causes temper brittleness.", "In hydrogen service, do not assume the notched strength of high-strength 4140: the room-temperature study lost about 60%.", "Take the safety data sheet for the specific bar before cutting, grinding or welding; no 4140 SDS was read here." ], "good_for": [ "Medium and large sections that need high strength with toughness after quenching and tempering (voestalpine).", "Gears, shafts, spindles, pinions and sprockets, the machine parts the supplier lists (Aircraft Materials)." ], "watch_out": [ "Hydrogen gas: notched tensile strength of high-strength 4140 fell from 2160 to 862 MPa at 69 MPa and room temperature.", "Dilute acid: 4140 rusted and corroded at 176.87 mpy in 0.5 M sulfuric acid after 144 h.", "Tempering between 200 and 420 C causes temper brittleness, so avoid that range." ], "verdict": "AISI 4140 is a strong, tough steel whose properties depend on heat treatment. Quote the condition with each value, keep hydrogen exposure in mind when choosing the strength level, and protect it from acid. The hydrogen data here come from one room-temperature study, so treat them as a warning, not a design allowable.", "recipe": { "line": "AISI 4140 is an iron-based chromium-molybdenum steel. The composition limits printed for it (ASTM A29, in the Sandia reference) are 0.38 to 0.43 wt% carbon, 0.75 to 1.00 manganese, 0.15 to 0.35 silicon, 0.80 to 1.10 chromium and 0.15 to 0.25 molybdenum, with phosphorus at 0.035 maximum, sulfur at 0.04 maximum and iron as the balance. Its strength comes from heat treatment (austenitize, quench, temper) as much as from its composition.", "parts": [ { "name": "Iron", "symbol": "Fe", "role": "The matrix of the steel; heat treatment changes its structure from austenite to martensite and then tempered martensite.", "share_note": "balance (the rest)" }, { "name": "Carbon", "symbol": "C", "role": "Sets how hard the steel can become when quenched; medium carbon gives the strength range.", "share_percent": 0.38, "share_high": 0.43 }, { "name": "Manganese", "symbol": "Mn", "role": "Deoxidiser and hardenability aid in the melt.", "share_percent": 0.75, "share_high": 1 }, { "name": "Silicon", "symbol": "Si", "role": "Deoxidiser in the melt.", "share_percent": 0.15, "share_high": 0.35 }, { "name": "Chromium", "symbol": "Cr", "role": "Adds hardenability and corrosion resistance; the grade is still a low-alloy steel, not stainless.", "share_percent": 0.8, "share_high": 1.1 }, { "name": "Molybdenum", "symbol": "Mo", "role": "Adds hardenability and, per the supplier, prevents temper brittleness.", "share_percent": 0.15, "share_high": 0.25 }, { "name": "Phosphorus", "symbol": "P", "role": "Impurity held low.", "share_percent": 0, "share_high": 0.035 }, { "name": "Sulfur", "symbol": "S", "role": "Impurity held low.", "share_percent": 0, "share_high": 0.04 } ] }, "risk_groups": [ { "title": "For people", "lead": "The PubChem records below are for elemental chromium and molybdenum. No safety data sheet for AISI 4140 bar was read in this run.", "points": [ { "label": "Chromium", "line": "PubChem lists elemental chromium as Danger, with H317, H319 and H334 among the reported codes. About half of 2404 company reports say it does not meet GHS criteria." }, { "label": "Molybdenum", "line": "PubChem lists elemental molybdenum with H361 (suspected of damaging fertility or the unborn child) and H228 (flammable solid) among the reported codes. 57.4% of reports say it does not meet GHS criteria." } ], "level": 0, "verdict": "Alloy not checked against an SDS" }, { "title": "In service", "lead": "These come from two laboratory tests, not from field incidents.", "points": [ { "label": "Hydrogen gas", "line": "In 69 MPa hydrogen gas at room temperature, high-strength 4140 lost about 60% of its notched tensile strength, from 2160 to 862 MPa (Sandia)." }, { "label": "Dilute acid", "line": "In 0.5 M sulfuric acid, 4140 rusted over its surface and corroded at 176.87 mpy after 144 h (Rosidah et al., 2021)." } ], "level": 1, "verdict": "Hydrogen and acid are the watch points" }, { "title": "Heat treatment", "lead": "Heat treatment sets the strength, and two windows need care.", "points": [ { "label": "Temper brittleness", "line": "Tempering between 200 and 420 C causes temper brittleness, per the supplier. Avoid that range." }, { "label": "Stress relief", "line": "After quenching and tempering, stress relieve about 30 to 50 C below the tempering temperature, then air cool." } ], "level": 1, "verdict": "Keep out of the tempering brittle range" } ] }, "updated": "2026-10-24", "review": { "status": "draft", "method": "assistant", "checked_values": 47, "unreachable": 4, "caveats": 3, "note": "Read by an AI assistant on 2026-10-24 from pages fetched in this run. Strength values are each tied to their heat treatment. Unreachable: Colombo 2020 (Cloudflare), MDPI Materials 18(2) 339 (Access Denied), Springer 10.1186/s44147-025-00702-z (challenge), arXiv 2012.10112 (truncated PDF)." }, "sources": { "voestalpine-4140": { "title": "voestalpine High Performance Metals: AISI 4140 / 1.7225 / G41400 datasheet", "id": "AISI 4140 / 1.7225 / G41400", "url": "https://www.voestalpine.com/highperformancemetals/australia/app/uploads/sites/265/2024/08/Datasheet-4140-2026-v1.pdf", "year": 2026, "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" }, "elgin-4140": { "title": "Alloy Steel Grade 4140 Fact Sheet (Elgin, mwcomponents.com), normalized at 870 C, 25 mm round", "id": "AISI 4140 normalized 870 C, 25 mm round", "url": "https://www.mwcomponents.com/uploads/Resource-Center/Elgin-Material-Sheets/Alloy-Steel-Grade-4140-Fact-Sheet_Elgin-Website.pdf", "kind": "datasheet", "license": "supplier datasheet, cited not reproduced" }, "aircraft-4140": { "title": "Aircraft Alloy Steel AISI 4140 (AMS 6349 / AMS 6382) Technical Data Sheet (Aircraft Materials)", "id": "AMS 6349 / AMS 6382", "url": "https://aircraftmaterials.com/data/alstst/4140.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" }, "sandia-1211": { "title": "Technical Reference on Hydrogen Compatibility of Materials: Low-Alloy Ferritic Steels, Tempered Fe-Cr-Mo Alloys (code 1211)", "id": "Sandia National Laboratories, Somerday, revised 12/05", "url": "https://www.sandia.gov/app/uploads/sites/158/2021/12/1211TechRef_FeCrMo_T.pdf", "year": 2005, "kind": "report", "license": "US government report, public" }, "itats-2021": { "title": "The effect of time variation on the steels corrosion rate in 0.5 M H2SO4 solution (Rosidah et al., JMESI 1(2))", "id": "doi:10.31284/j.jmesi.2021.v1i2.2183", "url": "https://ejournal.itats.ac.id/jmesi/article/download/2183/1989", "year": 2021, "kind": "paper", "license": "CC BY-NC 4.0" }, "usgs-chromium-2026": { "title": "USGS Mineral Commodity Summaries 2026: Chromium", "id": "mcs2026-chromium", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-molybdenum-2026": { "title": "USGS Mineral Commodity Summaries 2026: Molybdenum", "id": "mcs2026-molybdenum", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-critical-2025": { "title": "USGS: About the 2025 List of Critical Minerals", "id": "2025 List of Critical Minerals (60 minerals)", "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals", "year": 2025, "kind": "web", "license": "public domain (USGS)" }, "pubchem-chromium": { "title": "PubChem: Chromium (CID 23976), Safety and Hazards, GHS Classification", "id": "CID 23976", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON/?heading=GHS+Classification", "year": 2026, "kind": "database", "license": "PubChem terms (public)" }, "pubchem-molybdenum": { "title": "PubChem: Molybdenum (CID 23932), Safety and Hazards, GHS Classification", "id": "CID 23932", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON/?heading=GHS+Classification", "year": 2026, "kind": "database", "license": "PubChem terms (public)" }, "saky-4140": { "title": "Saky Steel: AISI 4140 1.7225 42CrMo4 SCM440 B7 Steel Bar", "id": "AISI 4140 1.7225 42CrMo4 SCM440 B7 Steel Bar", "url": "https://www.sakysteel.com/aisi-4140-1-7225-42crmo4-scm440-b7-steel-bar.html", "kind": "datasheet", "license": "supplier web page, cited not reproduced" }, "metinvest-42crmo4": { "title": "Metinvest: Steel 42CrMo4 characteristics, properties and analogues", "id": "Steel 42CrMo4 analogues table", "url": "https://metinvestholding.com/en/products/steel-grades/42crmo4", "kind": "datasheet", "license": "manufacturer web page, cited not reproduced" }, "tachart-709m40": { "title": "Tachart: 709M40 grade page with alias list", "id": "709M40 alias list", "url": "https://www.tachart.com/?p=1110", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/steel-4140/" }