SAE J406-2024 PDF

Full title and description

SAE International Standard J406 (J406_202402) — "Methods of Determining Hardenability of Steels". This standard defines the procedures, specimen dimensions and reporting requirements for conducting hardenability tests (end‑quench / Jominy type and subsize methods) for shallow and medium‑hardening steels.

Abstract

J406_202402 prescribes standardized methods for performing hardenability tests to determine how deeply steels harden when quenched from austenitizing temperature. It covers the 25 mm (1 in) end‑quench (Jominy) specimen and subsize procedures for smaller bars, describes hardness measurement and data recording practices, and specifies limitations (it does not apply to deep‑hardening steels that air‑harden). The document is intended to ensure repeatable, comparable hardenability data for material specification, heat‑treatment design and quality control.

General information

• Status: Stabilized.
• Publication date: February 23, 2024 (J406_202402).
• Publisher: SAE International.
• ICS / categories: 77.040 (Testing of metals); 77.140 (Iron and steel products) — metallurgy / heat‑treatment testing.
• Edition / version: J406_202402 (2024 revision / stabilized edition).
• Number of pages: 48 pages.

Scope

This standard prescribes procedures for making hardenability tests and recording results for shallow and medium hardening steels. It includes the 25 mm (1 in) standard end‑quench specimen for both medium and shallow hardening steels and gives a subsize method for bars less than 32 mm (1‑1/4 in) diameter. The standard excludes deep hardening steels that will normally air‑harden and refers users to SAE J1975 for methods related to case hardenability of carburized steels. Any alternate procedures require agreement between supplier and user.

Key topics and requirements

• Definition and measurement of hardenability (depth of hardening as a function of distance from quenched end).
• Use of the 25 mm (1 in) end‑quench (Jominy) specimen as the standard test geometry, with specified austenitizing and quench conditions.
• Subsize specimen procedures for bars under specified diameters (subsize method for bars <32 mm).
• Hardness testing method and locations along the specimen to produce a hardenability curve (reporting hardness vs. distance from quenched end).
• Data recording, reporting formats, and acceptance of standardized test conditions for inter‑laboratory comparability.
• Limitations and applicability (shallow/medium hardening steels only; not for deep‑hardening / air‑hardening steels).
• Cross‑references to other standards and information reports for case hardenability and related methods (e.g., SAE J1975, ASTM A255).

Typical use and users

Used by metallurgists, heat‑treat laboratories, materials engineers, steel producers, OEM materials/specification engineers (automotive, aerospace, industrial machinery), quality control labs, and standards committees to characterize and specify hardenability for material selection, heat‑treatment design and verification of production heats.

Related standards

Commonly referenced documents and equivalents include SAE J1975 (Case Hardenability of Carburized Steels) for case‑hardening considerations and ASTM A255 (Standard Test Methods for Determining Hardenability of Steel — Jominy end‑quench) which covers similar end‑quench test methods and calculation approaches; users often consult both SAE and ASTM documents when specifying tests.

Keywords

hardenability, Jominy, end‑quench, J406, steel heat treatment, hardenability test, subsize specimen, Jominy end quench, SAE, hardness curve, metallurgy

FAQ

Q: What is this standard?

A: SAE J406_202402 ("Methods of Determining Hardenability of Steels") is a SAE International technical standard that defines procedures and reporting for hardenability tests (Jominy/end‑quench and subsize methods) for shallow and medium hardening steels.

Q: What does it cover?

A: It covers specimen geometry (25 mm / 1 in end‑quench specimen), test procedures, subsize methods for smaller bars, hardness measurement locations and reporting formats, and limitations on applicability (not for deep‑hardening air‑hardening steels).

Q: Who typically uses it?

A: Metallurgists, heat‑treat and QC laboratories, steel suppliers, OEM material engineers (automotive, aerospace, industrial equipment) and standards writers use J406 to produce repeatable hardenability data for specifications and heat‑treatment design.

Q: Is it current or superseded?

A: The document is published as J406_202402 and is listed as Stabilized (February 23, 2024). Users should verify the current status on SAE International's catalog for any later revisions or reaffirmations.

Q: Is it part of a series?

A: J406 is part of SAE's metallurgy/heat‑treatment standards family and is commonly used alongside SAE information reports and related standards such as J1975 for case hardenability; equivalent or complementary test methods are also available from ASTM (e.g., ASTM A255).

Q: What are the key keywords?

A: Hardenability, Jominy, end‑quench, heat treatment, steel, hardenability curve, SAE J406, subsize specimen.