ASTM A668/A668M-23 PDF

Full title and description

ASTM A668/A668M-23 — Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use. This specification establishes requirements for untreated and heat‑treated carbon and alloy steel forgings intended for general industrial applications, including classification by heat treatment and mechanical properties, mandatory chemical and mechanical testing, optional supplementary requirements, and labeling/certification provisions.

Abstract

ASTM A668/A668M-23 defines classes of carbon (Classes A–F) and alloy (Classes G, H, J–N) steel forgings, the required forging and heat‑treatment processes for each class, and minimum chemical and mechanical property requirements. The standard prescribes testing and inspection practices (chemical analysis, tensile properties, hardness, and relevant non‑destructive examinations), references common test methods, and provides optional supplementary requirements for purchaser specification. SI and inch‑pound units are provided as separate systems.

General information

• Status: Active / Valid
• Publication date: May 1, 2023
• Publisher: ASTM International
• ICS / categories: 77.140.85 (Iron and steel forgings)
• Edition / version: A668/A668M-23
• Number of pages: 10

Scope

This specification covers untreated and heat‑treated carbon and alloy steel forgings manufactured by hot mechanical working for general industrial use. It excludes hot‑rolled or cold‑finished bars. The standard lists six carbon‑steel classes and seven alloy‑steel classes, prescribes required heat treatments for each class, and sets required chemical composition limits and mechanical property minima. Supplementary requirements (including those of Specification A788/A788M) apply only when specified by the purchaser. Values in SI and inch‑pound units are provided separately and are not to be interchanged.

Key topics and requirements

• Classification of forgings into carbon (A–F) and alloy (G, H, J–N) classes with associated heat‑treatment regimes.
• Requirement that forgings be produced by hot mechanical working (forgings only; bars excluded).
• Mandatory chemical analysis and product analysis to meet composition limits (including Mn, P, S, etc.).
• Mechanical property requirements: tensile strength, yield (where specified), elongation, reduction of area, and Brinell hardness limits.
• Provision for supply on hardness testing only using the suffix “H” (certification and marking after hardness testing).
• Referenced test and examination methods (examples: A275/A275M, A370, A388/A388M, A788/A788M, E290, E340) for inspection and mechanical testing.
• Optional supplementary requirements available when specified by the purchaser.
• Separate SI and inch‑pound units — each unit system is independently normative.

Typical use and users

Used by forging manufacturers and suppliers, procurement and specification engineers, quality and inspection personnel, OEMs and fabricators requiring general‑purpose steel forgings, and purchasing organizations for industrial equipment. Typical applications are general industrial components where standardized classes and proven heat treatments provide predictable mechanical properties and traceable certification.

Related standards

Commonly referenced and related standards include ASTM A788/A788M (general requirements for steel forgings), A275/A275M (magnetic particle examination), A370 (mechanical testing methods), A388/A388M (ultrasonic examination), E290 (bend testing), and E340 (macroetching). Appendix material provides correspondence to earlier classes from A235, A237, and A243. This edition replaces ASTM A668/A668M-22 and is the current A668/A668M designation.

Keywords

steel forgings, carbon steel forgings, alloy steel forgings, heat treatment classes, normalized, quenched and tempered, tensile properties, Brinell hardness, chemical analysis, forgings specification, ASTM A668

FAQ

Q: What is this standard?

A: ASTM A668/A668M-23 is a specification that sets classification, chemical, mechanical, heat‑treatment, and testing requirements for carbon and alloy steel forgings used in general industrial applications.

Q: What does it cover?

A: It covers untreated and heat‑treated steel forgings produced by hot mechanical working, defines classes of forgings with required heat treatments and mechanical property minima, prescribes chemical and mechanical testing requirements, and allows purchaser‑specified supplementary requirements. It does not cover hot‑rolled or cold‑finished bars.

Q: Who typically uses it?

A: Forging manufacturers, specifiers and purchasing engineers, quality/inspection personnel, fabricators, and OEMs requiring standardized forgings for general industrial use.

Q: Is it current or superseded?

A: It is current. The A668/A668M-23 edition was approved and published May 1, 2023, and replaces ASTM A668/A668M‑22.

Q: Is it part of a series?

A: Yes. It is maintained under ASTM Committee A01 (Subcommittee A01.06 on Steel Forgings and Billets) and closely related to other forging standards (for example A788/A788M and the referenced test methods). The standard also provides class correspondences to earlier specifications such as A235, A237, and A243.

Q: What are the key keywords?

A: Steel forgings, carbon steel, alloy steel, heat treatment, normalized, quenched and tempered, tensile strength, Brinell hardness, chemical analysis, ASTM A668.