GB/T 31935-2015Corrosion of metals and alloys—Corrosion test for intergranular corrosion susceptibility of low-Cr ferritic stainless steels (English PDF)

Foreword

This Standard was drafted as per the rules specified in GB/T 1.1-2009.

1 Scope

This Standard specifies the specimen, test instrument and test equipment, test solution, test conditions and procedure, test result assessment and test report of corrosion test for intergranular corrosion susceptibility of low-cr ferritic stainless steel.

This Standard is applicable to inspect the low-cr ferritic stainless steel (generally the chromium content is less than 16%) in the weakly oxidizing corrosive media by the sulfuric acid-copper sulfate corrosion test.

2 Normative References

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.

GB/T 5231 Designation and Chemical Composition of Wrought Copper and Copper Alloys

GB/T 625 Chemical Reagent - Sulfuric Acid

GB/T 665 Chemical Reagent - Copper (II) Sulfate Pentahydrate

3 Specimen

6 Test Conditions and Procedures

6.6 After the test, take out the specimen to clean and dry.

7 Assessment of Test Results

7.1 For the specimen with insignificant uniform corrosion (specimen isn't thinned or specimen surface has no obvious corrosive products covering), the metallographic method shall be used to assess the resistance to intergranular corrosion of the test materials.

7.2 Conduct the sampling analysis against the specimen section; the sampling length of section is recommended to be 15mm~20mm; observe the maximum intergranular corrosion depth of the specimen section through the metallographic method.

7.3 If the test material is weld seam specimen, when performing the section sampling to analyze its intergranular corrosion depth, the section direction of specimen shall be perpendicular to the weld seam; and cutting surface shall contain the weld seam zone and weld seam heat affected zone.

7.4 The data of specimen with the most serious corrosion shall be regarded as the standard to assess the test results.

8 Test Report

Test report shall contain the following contents.

a) Specimen name and test area size;

b) If sensitizing treatment is performed, the sensitizing treatment system shall be recorded;

c) Test solution, and test time; d) Test results. […]