Round bar \u00b7 flat bar \u00b7 plate \u00b7 sheet \u00b7 tube \u00b7 forging \u00b7 wire \u00b7 welding wire \u00b7 hollow bar. All forms are supplied to order. Carpenter’s own product list gives the same forms (bar, hollow bar, rounds, billet, plate, strip, sheet, wire, weld wire), but the AMS coverage is limited to bars, forgings and forging stock \u2014 see the standards map.<\/div>\n<\/div>\n
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Standards<\/div>\n
AMS (verified):
AMS 6532<\/b> \u2014 ‘Steel, Bars and Forgings, and Forging Stock 3.1Cr – 11.5Ni – 13.5Co – 1.2Mo (0.23 – 0.25C) Vacuum Melted, Normalized and Overaged Precipitation Hardenable’. Scope: bars, forgings of 645 cm\u00b2 (100 in\u00b2) cross-sectional area and under, and forging stock of ANY size. It is the 280 ksi (1931 MPa) tensile class. The current revision is L-2024. \u00b7 AMS 6478<\/b> \u2014 the 290 ksi (1999 MPa) tensile class of the same alloy; title ‘Steel, Bars and Forgings 3.1Cr 11.5Ni 13.5Co 1.2Mo (0.21 – 0.25C) Vacuum Melted, Annealed Heat Treatable to 290 ksi’. Forms: bars, forgings, forging stock. ITS STATUS IS DISPUTED; see the standards note. Military and customer specifications: MIL-HDBK-5 (design data) \u00b7 McDonnell Douglas MMS 217 \u00b7 MIL-STD-2154 Type 1 Class A (this is an ULTRASONIC INSPECTION specification, not a material specification). ASTM: no ASTM number covering this alloy could be confirmed across four independent sources, so none is given.
AMS 6532 AND AMS 6478 ARE DIFFERENT STRENGTH CLASSES OF THE SAME ALLOY and are not interchangeable: 6532 is the 280 ksi (1931 MPa) class, 6478 the 290 ksi (1999 MPa) class, with a 245 ksi (1689 MPa) yield floor.<\/span><\/div>\n<\/div>\n\n
Advantage<\/div>\n
Its single most important practical advantage is that it keeps its fracture toughness at yield strengths above 1700 MPa. Carpenter gives typical longitudinal values of 1724 MPa yield \/ 1965 MPa tensile together with K_Ic 126 MPa\u00b7m^0.5 (115 ksi\u00b7in^0.5), Charpy V 41 J (30 ft-lb), 14% elongation and\u2026<\/div>\n<\/div>\n
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Welding<\/div>\n
IT IS WELDABLE. The SSA Corp data sheet states ‘Weldable requiring no preheating’, that is, NO PREHEAT IS REQUIRED; the
AMS 6478<\/b> title record likewise defines the alloy for applications requiring ‘high strength, toughness, and weldability’.<\/div>\n<\/div>\n\n
Limits<\/div>\n
1) IT IS NOT STAINLESS. Chromium is 3.10% and no passive film forms. Carpenter rates general corrosion resistance as ‘Humidity Restricted’ and adds that ‘corrosion testing is recommended’; Titanium Industries states plainly that ‘AerMet 100 is not corrosion resistant, so it must be sealed if used in moist environments’;<\/div>\n<\/div>\n