ASTM G28 - 02(2008)

    Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys

    Active Standard ASTM G28 | Developed by Subcommittee: G01.05

    Book of Standards Volume: 03.02


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    Significance and Use

    The boiling ferric sulfate-sulfuric acid test may be applied to the following alloys in the wrought condition:

    Alloy Testing Time, h
    N06007 120
    N06022 24
    N06030120
    N06059 24
    N06200 24
    N06455 24
    N06600 24
    N06625120
    N06686 24
    N06985120
    N08020120
    N08367 24
    N08800120
    N08825A120
    N10276 24
    ____________

    A While the ferric sulfate-sulfuric acid test does detect susceptibility to inter- granular corrosion in Alloy N08825, the boiling 65 % nitric acid test, Practices A 262, Practice C, for detecting susceptibility to intergranular corrosion in stainless steels is more sensitive and should be used if the intended service is nitric acid.

    This test method may be used to evaluate as-received material and to evaluate the effects of subsequent heat treatments. In the case of nickel-rich, chromium-bearing alloys, the test method may be applied to wrought and weldments of products. The test method is not applicable to cast products.

    1. Scope

    1.1 These test methods cover two tests as follows:

    1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3-10, inclusive)This test method describes the procedure for conducting the boiling ferric sulfate50 % sulfuric acid test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to intergranular corrosion (see Terminology G 15), which may be encountered in certain service environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022, N06059, and N06455.

    1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11-18, inclusive)This test method describes the procedure for conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increase in corrosion rate when there are high levels of grain boundary precipitation.

    1.2 The purpose of these two test methods is to detect susceptibility to intergranular corrosion as influenced by variations in processing or composition, or both. Materials shown to be susceptible may or may not be intergranularly corroded in other environments. This must be established independently by specific tests or by service experience.

    1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Warning statements are given in 5.1.1, 5.1.3, 5.1.9, 13.1.1, and 13.1.11.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

    D1193 Specification for Reagent Water

    G15 Terminology Relating to Corrosion and Corrosion Testing


    ICS Code

    ICS Number Code 77.120.40 (Nickel, chromium and their alloys)

    UNSPSC Code

    UNSPSC Code 11101704(Steel)


    DOI: 10.1520/G0028-02R08

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