GB/T 32571-2016 English PDFUS$379.00 · In stock
Delivery: <= 4 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 32571-2016: Corrosion of metals and alloys -- Corrosion test for intergranular corrosion susceptibility of high-Cr ferritic stainless steels Status: Valid
Basic dataStandard ID: GB/T 32571-2016 (GB/T32571-2016)Description (Translated English): Corrosion of metals and alloys -- Corrosion test for intergranular corrosion susceptibility of high-Cr ferritic stainless steels Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: H25 Classification of International Standard: 77.060 Word Count Estimation: 19,146 Date of Issue: 2016-02-24 Date of Implementation: 2017-01-01 Quoted Standard: GB/T 625; GB/T 665; GB/T 8170; GB/T 9854; GB/T 20878-2007 Regulation (derived from): National Standard Announcement No Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China Summary: This standard specifies the intergranular corrosion test methods for high chromium ferritic stainless steels, including test specimens, test solutions, test instruments and equipment, test conditions and procedures, evaluation of test results and test reports. This standard applies to chromium content of not less than 16% of the ferrite stainless steel intergranular corrosion test. Including the following four test methods (see Appendix A, Table A.1, for the stainless steel grades applicable to each method): a) Method W 10% oxalic acid etching test Method for screening intergranular corrosion susceptibility tests for ferritic stainless steels, The samples were electrolytically etched in 10% oxalic acid solution and the microstructure of the etched surface was observed under a microscope to determine whether a long-term hot acid test of Method X, Method Y, Method Z was required. B) Method X Test method for sulfuric acid-ferric sulfate corrosion GB/T 32571-2016: Corrosion of metals and alloys -- Corrosion test for intergranular corrosion susceptibility of high-Cr ferritic stainless steels---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. Corrosion of metals and alloys.Corrosion test for integranular corrosion susceptibility of high-Cr ferritic stainless steels ICS 77.060 H25 National Standards of People's Republic of China Corrosion of high chromium ferritic bodies of metals and alloys Stainless steel intergranular corrosion test method Published on.2016-02-24 2017-01-01 implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration issued ContentForeword I 1 Scope 1 2 Normative references 1 3 sample 1 4 Method W 10% oxalic acid etching test method 6 5 Method X Sulfuric acid-ferric sulfate corrosion test method 9 6 method Y copper-copper sulfate-50% sulfuric acid corrosion test method 10 7 Method Z Copper-copper sulfate-16% sulfuric acid corrosion test method 12 Appendix A (informative) Method for evaluating the sensitivity of intergranular corrosion of ferritic stainless steels 14ForewordThis standard was drafted in accordance with the rules given in GB/T 1.1-2009. This standard was proposed by the China Iron and Steel Association. This standard is under the jurisdiction of the National Steel Standardization Technical Committee (SAC/TC183). This standard was drafted. Shanxi Taigang Stainless Steel Co., Ltd., Metallurgical Industry Information Standards Institute. The main drafters of this standard. Xue Wenling, Ren Yongxiu, Hou Jie, Jia Yuanwei, Zhang Jiansheng. Corrosion of high chromium ferritic bodies of metals and alloys Stainless steel intergranular corrosion test method1 ScopeThis standard specifies the sample, test solution, test equipment and equipment, test strip of the intergranular corrosion test method for high chromium ferritic stainless steel. Parts and procedures, evaluation of test results and test reports. This standard applies to the intergranular corrosion test of ferritic stainless steel with a chromium content of not less than 16%. Includes the following 4 test methods (appendix Table A.1 of A gives the stainless steel grades applicable to each method). a) Method W 10% oxalic acid etching test method Screening test for the sensitivity of intergranular corrosion of ferritic stainless steel. After the sample is electrolytically etched in 10% oxalic acid solution, it is in the microscope. The metallographic structure of the etched surface was observed to determine whether a long-term thermal acid test of Method X, Method Y, and Method Z was required. b) Method X sulfuric acid-iron sulfate corrosion test method Applicable to the evaluation of intergranular corrosion by weight loss or microscopic observation after boiling test of ferritic stainless steel in sulfuric acid-ferric sulfate solution tendency. c) Method Y copper-copper sulfate-50% sulfuric acid corrosion test method Applicable to the evaluation of ferritic stainless steel after boiling in copper-copper sulfate-50% sulfuric acid solution, by weight loss or microscopic observation Intergranular corrosion tends. d) Method Z copper-copper sulfate-16% sulfuric acid corrosion test method Applicable to the determination of intergranular corrosion by bending or metallographic phase after boiling test of ferritic stainless steel in copper-copper sulfate-16% sulfuric acid solution tendency.2 Normative referencesThe following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article. Pieces. For undated references, the latest edition (including all amendments) applies to this document. GB/T 625 chemical reagent sulfuric acid GB/T 665 chemical reagent anhydrous copper (II) sulfate (copper sulfate) GB/T 8170 Numerical Rounding Rules and Representation and Determination of Limit Values GB/T 9854 chemical reagent oxalic acid dihydrate (oxalic acid) GB/T 20878-2007 Stainless steel and heat resistant steel grades and chemical composition3 sample3.1 Sampling and preparation 3.1.1 Samples of pressure-treated steel are sampled from steel of the same heat number, the same specification and the same batch of heat-treated batches. 3.1.2 Plate welded joints shall be taken from the same parent metal and using the same welding process. 3.1.3 Welded pipe samples are taken from welded pipes of the same heat number, the same specification and the same heat treatment batch. 3.1.4 The sample is machined for cutting. If shearing or other methods are used, the effect of shearing should be removed by cutting or grinding. section. 3.1.5 The surface of the sample should be close to the original surface state of the product. The sample for the welded joint should include the base metal, heat affected zone and weld metal. s surface. Method X, Method Y sample size and preparation requirements are shown in Table 1, method Z sample size and preparation requirements are shown in Table 2. 3.1.6 Method W The surface to be inspected shall be polished for corrosion and microstructure inspection. 3.1.7 Method X, Method Y, Method Z When there is scale on the sample, it shall be removed by cutting or grinding. Test that requires sensitization As such, it should be ground after sensitization. Samples that cannot be ground can be pickled and the surface must not be pickled. Can't grind Or the pickled sample, the surface cannot be oxidized during heat treatment. 3.1.8 Method X, Method Y, Method Z When the sample is cut and surface-grinded, the surface shall be prevented from overheating. The surface roughness Ra of the sample to be tested shall be The value is not more than 0.8 μm. Table 1 Method X and Method Y sample size and preparation category specification Mm Sample size Mm length Width Thickness Number of samples Description Steel plate, belt (flat steel) Thickness ≤ 3 30 ± 1020 ± 10 2 Sampling along the rolling direction Thickness >3 30±1020±10 3~4 2 Sampling in the rolling direction, one sample is machined from one side to the sample Thickness, another sample is machined from the other side to the thickness of the sample Sheet welding Connector Single weld 30±1020±10 3~4 2 The weld is located in the middle, as shown in Figure 1. Cross weld seam 30±1020±10 3~4 4 The weld intersection is located in the middle of the sample, and the two samples are inspected for transverse welding. Seam, two specimens are tested for longitudinal welds, see Figure 2 Seamless steel pipe Outer diameter < 5 30±10 2 5≤outer diameter≤1530±10 2 Take semi-tubular or boat-shaped specimen Outer diameter >15 30±10 ≤20 2 (wall thickness ≤ 3mm) 4 (wall thickness > 3mm) Take a semi-tubular or boat-shaped specimen. When the wall thickness is greater than 3mm, one Group samples are machined from the outer wall to the thickness of the sample, and the other group is from the inner wall. Processing to sample thickness Welded pipe Thickness ≤ 3 30 ± 10 2 Take a semi-tubular or boat-shaped specimen with the weld along the length of the specimen. In the middle of the sample, see Figure 3. For the boat sample, the sample base material Edge to fusion line distance, both sides are not less than 10mm, sample Samples to be sensitized without processing the inner and outer surfaces The surface treatment for removing the oxide film can be performed after sensitization. For large diameter pipes, curved specimens can also be used, the number is doubled, and the weld is welded. Located in the center of the curved specimen. See Figure 4 Thickness >3 30±10 3~4 4 When the wall thickness is greater than 3mm, the sample is divided into two groups, each of which is two Sheet, a set of specimens from the outer wall to the required thickness, another set from The inner wall is machined to the required thickness. Other requirements are the same as above Table 2 Method Z sample size and preparation category specification Mm Sample size Mm length Width Thickness Number of samples Description Steel plate, belt (flat steel) Thickness ≤3 80~100 20 2 Sampling along the rolling direction, each sample is bent after the test Tested surface Thickness >3 80~100 20 3~4 4 Sampling in the rolling direction, two samples are machined from one side to the sample Thickness, two samples were machined from the other side to the thickness of the sample. test After the test, each bends its corresponding one of the tested faces Sheet welding Connector Single weld 80~100 20 3~4 2 The weld is located in the middle and is bent after the test. Face, sampling is shown in Figure 1. Cross weld 80~10020~35 3~4 4 The weld intersection is located in the middle of the sample, and the two samples are inspected for transverse welding. Seam, two specimens are tested for longitudinal welds, and the corresponding bends after the test A test surface, sampled as shown in Figure 2 Seamless steel pipe Outside diameter < 5 80~100 2 Take a whole section of tubular specimen (both inner and outer walls need to be tested, if the inner wall cannot When the bending is evaluated, it is evaluated by metallographic method) 5≤outer diameter≤1580~100 2 Take a semi-tubular or boat-shaped specimen, each specimen is bent after the test Two tested faces Outer diameter >15 80~100 ≤20 2 (wall thickness ≤ 3mm) 4 (wall thickness > 3mm) Take a semi-tubular or boat-shaped specimen. When the wall thickness is greater than 3mm, one Group samples are machined from the outer wall to the thickness of the sample, and the other group is from the inner wall. After processing to the thickness of the sample, each test is bent after the test. Face Welded pipe Thickness ≤3 80~100 2 Take a semi-tubular or boat-shaped specimen with the weld along the length of the specimen. In the middle of the sample, see Figure 3. For the boat sample, the sample base material Edge to fusion line distance, both sides are not less than 10mm, sample The inner and outer surfaces are not processed, and each sample is bent after the test. Two tested faces. The sample to be sensitized can be removed after sensitization Surface treatment of the film. For large diameter tubes, curved specimens can also be used, the number is doubled, welding The slit is located in the center of the curved specimen, see Figure 4. Weld seam when bending The line is at the center of the bend Thickness >3 80~100 3~4 4 When the wall thickness is greater than 3mm, the sample is divided into two groups, each of which is two Sheet, a set of specimens from the outer wall to the required thickness, another set from The inner wall is machined to the required thickness. When bent, the unmachined surface is located at the bend. The outer side of the curve. Other requirements are the same as above The unit is mm Description. 1---non-sampling area; 2---welding sample; 3---welding board; 4---non-sampling area; l---sampling length; b---Sampling width. Figure 1 Single seam sampling of sheet The unit is mm Description. 1---welding sample; 2---welding sample; 3---welding board; l---sampling length; b---Sampling width. Figure 2 Sheet cross weld sampling The unit is mm Description. 1---welding base metal; 2---weld pipe sample; 3---weld; l---Sampling length. Figure 3 Sampling of the welded boat The unit is mm Description. 1---welding base metal; 2---weld pipe sample; 3---weld; l---Sampling length. Figure 4 Sampling of curved sample of welded pipe 3.2 Sensitization of the sample 3.2.1 The specific sensitization system or welding process shall be determined by both the supplier and the buyer in accordance with the actual application conditions. 3.2.2 Pre- and pre-test samples are degreased and dried with a suitable cleaning agent (non-chloride). 3.2.3 Sensitization of the sample is carried out before grinding. If the material is used in the supplied state without welding or heat treatment, the sample does not have to be carried out. Sensitization. If the material is used in a welded or heat treated condition, the specimen shall be welded or heat treated in the same manner. 4 Method W 10% oxalic acid etching test method 4.1 Test solution 100 g of the superior grade oxalic acid conforming to GB/T 9854 was dissolved in 900 mL of distilled water or deionized water to prepare a 10% oxalic acid solution. 4.2 Test equipment and equipment 4.2.1 For the etch test, it can provide 15V and 20A DC power supply, variable resistor, and ammeter of 0A~30A range. 4.2.2 The cathode is a steel cup made of stainless steel or a steel sheet with a sufficiently large surface area. Other suitable inert electrodes may also be used. The anode is a sample, If a steel sheet is used as the cathode, a suitable shape of the conductive fixture should be used to keep the sample in the test solution. The electrolytic etching device is shown in Fig. 5. 4.2.3 Metallographic microscope. a) For large samples, b) for small samples The unit is mm c) Stainless acid-resistant steel container Description. 1---stainless steel container; 2---sample; 3---DC power supply; 4---varistor; 5---current meter; 6---switch; 7---acid resistant rubber ring. Figure 5 Electrolytic etching device diagram 4.3 Test conditions and procedures 4.3.1 The etched sample is used as the anode, and the stainless steel cup or stainless steel sheet or other suitable inert electrode is used as the cathode. Pour 10% oxalic acid solution. Liquid, turn on the current. The anode current density was 1 A/cm 2 , the etching time was 1.5 min, and the etching solution temperature did not exceed 50 ° C. 4.3.2 After the sample is etched, rinse the surface of the sample with hot water, wash it, and rinse it with alcohol or acetone. Observing the sample under a metallographic microscope For all etched surfaces, the magnification is.200 to 500 times, and the types of tissues are determined according to Table 3 and Figs. 6 to 8. 4.3.3 A new solution should be used for each test. 4.4 Classification of etched tissue 4.4.1 The classification of the etched tissue showing grain boundary morphology is shown in Table 3. 4.4.2 Class I and Class II organizations are acceptable organizations and do not have to be tested by other methods. Three types of organizations are unacceptable organizations, and methods are needed. Test of X, Method Y, Method Z. Table 3 Classification of grain boundary morphology Category name organization characteristics A class of stepped grain boundaries has no corrosion grooves, and the grains are stepped. See Figure 6. The second type of mixed structure has a corroded groove at the grain boundary, but none of the grains are completely surrounded by the corrosion groove. See Figure 7 The grain boundaries of the three types of gully structures have corroded trenches, and one or more grains are completely surrounded by corroded trenches, as shown in Fig. 8. Figure 6 Schematic diagram of ladder organization (category) Figure 7 Schematic diagram of mixed organization (category 2) Figure 8 Schematic diagram of sulcus (three types) 4.5 Test report The test report should include the following. a) the name of this standard; b) test method; c) the name of the sample and the test area size; d) current density; e) etching time and temperature; f) metallographic photographs after etching; g) Judgment results. 5 Method X sulfuric acid-ferric sulfate corrosion test method 5.1 Test solution 5.1.1 Add 236mL of superior grade pure sulfuric acid in accordance with GB/T 625 slowly into the conical flask containing 400mL of distilled water to prepare sulfuric acid. Solution (avoid boiling due to exotherm). 5.1.2 Weigh 25g of ferric sulfate with a balance [Iron sulfate content (mass fraction) in terms of Fe is 21.0%~23.0% of excellent grade], adding sulfur In an acid solution. 5.1.3 Place the zeolite in the flask. 5.1.4 Lubricate the conical flask interface with silicone grease. 5.1.5 Connect the condenser connection and the conical flask connection. 5.1.6 Boil the solution until all the ferric sulphate has dissolved. 5.2 Test equipment and equipment 5.2.1 The instrument used is shown in Figure 9, or a 1L lap cone with a reflux condenser. 5.2.2 A heating device that maintains the test solution in a slightly boiling state. 5.2.3 Vernier calipers. 5.2.4 Analytical balance (accurate to 0.001g). 5.2.5 Microscope (magnification of at least 40 times). 5.2.6 Glass Bracket (hard primary glass specified in glassware for chemical analysis, the size can pass through the conical bottle mouth, there must be 3 on it~ 4 holes to increase the circulation of the solution around the sample). 5.3 Test conditions and procedures 5.3.1 Measure the size of the sample and calculate the surface area of the sample (take 3 significant figures). 5.3.2 De-oil, clean, dry and weigh the sample (accurate to 1 mg) with a suitable cleaning agent (non-chloride) before the test. 5.3.3 Place the sample on the glass holder, immerse it in the boiling test solution, keep the holder in the middle of the solution, and put only one test in each container. kind. The continuous boiling time is shown in Table A.1. The soaking time required for the grades not listed in Table A.1 is determined by negotiation between the supplier and the buyer. 5.3.4 After the test, the sample is taken out, and the surface corrosion product is brushed off with soft brush in running water, washed, dried and weighed. 5.3.5 According to the agreement between the supplier and the buyer, the test results are assessed by weightlessness or microscopic observation. 5.4 Evaluation of test results 5.4.1 The weight loss assessment test results are evaluated by corrosion rate, and the corrosion rate [g/(m2·h)] is calculated according to formula (1). GB/T 8170 for numerical rounding, repaired to the second decimal place. Corrosion rate = M1-m2 S×t (1) In the formula. M1---the mass of the sample before the test, the unit is gram (g); M2---the mass of the sample after the test, the unit is gram (g); S --- sample surface area, the unit is square meters (m2); t --- Test time in hours (h). 5.4.2 Microscopic observation The test results were evaluated. The sample was placed under a binocular microscope and magnified 40 times. The evidence of intergranular corrosion was crystal grain removal. The number of grains falling off the unit area of the metal surface caused by intergranular corrosion cannot exceed the negotiated value of both the supply and the demand. 5.5 Test report The test report should include the following. a) the name of this standard; b) test method; c) the name and size of the sample; d) the sensitization system should be recorded if sensitized; e) test time; f) the quality of the sample before and after the test; g) corrosion rate of the sample [g/(m2 · h)]; h) Microscopic observations. 6 method Y copper-copper sulfate-50% sulfuric acid corrosion test method 6.1 Test solution 6.1.1 Add 236mL of superior grade pure sulfuric acid in accordance with GB/T 625 into the conical flask containing 400mL of distilled water to prepare sulfuric acid. Solution (avoid boiling due to exotherm). 6.1.2 Weigh 72g of analytical pure copper sulfate (CuSO4·5H2O) in accordance with GB/T 665 and add to the sulfuric acid solution. 6.1.3 Place the copper piece on a glass stand and place it in a conical flask. 6.1.4 Place the zeolite in an Erlenmeyer flask. 6.1.5 Lubricate the conical flask interface with silicone grease. 6.1.6 Con......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 32571-2016_English be delivered?Answer: Upon your order, we will start to translate GB/T 32571-2016_English as soon as possible, and keep you informed of the progress. The lead time is typically 2 ~ 4 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB/T 32571-2016_English with my colleagues?Answer: Yes. 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