Active Standard ASTM A638 / A638M | Developed by Subcommittee: A01.17
Book of Standards Volume: 01.03
Historical (view previous versions of standard)
This specification covers hot-finished or cold-finished precipitation hardening iron base superalloy bars, forgings, and forging stock for high-temperature service. The mechanical properties of these alloys are developed by suitable solution treating and precipitation hardening treatments. Two grades of iron base alloy are covered; Grade 660 and Grade 662 (bars and forgings). The material shall meet the requirements as to stress rupture properties specified. The material shall conform to the chemical, mechanical, and metallurgical properties requirements specified.
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1.1 This specification covers hot-finished or cold-finished precipitation hardening iron base superalloy bars, forgings, and forging stock for high-temperature service. The mechanical properties of these alloys are developed by suitable solution treating and precipitation hardening treatments.
1.2 Two grades of iron base alloy are covered. Selection will depend upon design, service conditions, mechanical properties, and elevated temperature characteristics.
1.3 The values stated in either inch-pound units or SI (metric) units are to be regarded separately as standards; within the text and tables, the SI units are shown in [brackets]. The values stated in each system are not exact equivalents; therefore, each system must be used independent of the other. Combining values from the two systems may result in nonconformance with the specification.
1.4 Unless the order specifies an “M” designation, the material shall be furnished to inch-pound units.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A484/A484M Specification for General Requirements for Stainless Steel Bars, Billets, and Forgings
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
E30 Test Methods for Chemical Analysis of Steel, Cast Iron, Open-Hearth Iron, and Wrought Iron
E527 Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
ICS Number Code 77.140.60 (Steel bars and rods); 77.140.85 (Iron and steel forgings)