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

^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 sulfate — 50 % 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

Keywords

corrosion test; ferric sulfate; intergranular; nickel-rich; Ferric sulfate test; Intergranular attack (IGA); Nickel alloys (corrosion testing); Nickel-chromium alloys; Nonferrous metals/alloys; Stainless steel (corrosion testing); UNS N06007 (Ni-Cr alloy, Hastelloy G); UNS N06022 (Ni-Cr-Mo alloy, Hastelloy C-22); UNS N06030 (wrought Ni-Cr-Fe-Mo-Cu alloy, Hastelloy G-30); UNS N06059 (low carbon Ni-Cr-Mo alloy, Alloy 59); UNS N06200 (Ni-Cr-Mo-Cu alloy, Hastelloy C-2000); UNS N06455 (Ni-Cr alloy, Hastelloy C-4); UNS N06600 (Ni-Cr alloy, Inconel 600); UNS N06985 (Ni-Cr alloy ERNiCrMo-9, Hastelloy G-3); UNS N06625 (Ni-Cr alloy, Inconel 625); UNS N08020 (Ni-Fe-Cr alloy, Carpenter 20Cb3); UNS N06686 (Ni-Cr-Mo-W alloy, Inconel 686); UNS N08367 (Cr-Ni-Mo-N alloy, AL 6XN); UNS N08800 (Fe-Ni-Cr alloy, Incoloy 800); UNS N08825 (Ni-Fe-Cr alloy, Incoloy 825); UNS N10276 (Ni-Mo alloy, Hastelloy C276); Boiling ferric sulfate; Chromium alloys; Chromium alloy steel;

ICS Code

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

Citing ASTM Standards

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