1. Scope*
1.1 These practices cover the following five tests:
1.1.1 Practice A—Oxalic Acid Etch Test for Classification
of Etch Structures of Austenitic Stainless Steels (Sections 4 to
13, inclusive),
1.1.2 Practice B—Ferric Sulfate-Sulfuric Acid Test for Detecting
Susceptibility to Intergranular Attack in Austenitic
Stainless Steels (Sections 14 to 25, inclusive),
1.1.3 Practice C—Nitric Acid Test for Detecting Susceptibility
to Intergranular Attack in Austenitic Stainless Steels
(Sections 26 to 36, inclusive),
1.1.4 Practice E—Copper–Copper Sulfate–Sulfuric Acid
Test for Detecting Susceptibility to Intergranular Attack in
Austenitic Stainless Steels (Sections 37 to 46, inclusive), and
1.1.5 Practice F—Copper–Copper Sulfate–50 % Sulfuric
Acid Test for Detecting Susceptibility to Intergranular Attack
in Molybdenum-Bearing Austenitic Stainless Steels (Sections
47 to 58, inclusive).
1.2 The Oxalic Acid Etch Test is a rapid method of
identifying, by simple etching, those specimens of certain
stainless steel grades that are essentially free of susceptibility
to intergranular attack associated with chromium carbide
precipitates. These specimens will have low corrosion rates in
certain corrosion tests and therefore can be eliminated
(screened) from testing as “acceptable.” The etch test is
applicable only to those grades listed in the individual hot acid
tests and classifies the specimens either as “acceptable” or as
“suspect.”
1.3 The ferric sulfate-sulfuric acid test, the copper–copper
sulfate–50 % sulfuric acid test, and the nitric acid test are based
on weight loss determinations and, thus, provide a quantitative
measure of the relative performance of specimens evaluated. In
contrast, the copper–copper sulfate–16 % sulfuric acid test is1762
