GB/T 4334.1-2000 Test method for 10% oxalic acid etching of stainless steel

This standard specifies the test specimens, test solutions, test equipment, test conditions and procedures, evaluation of test results and test reports for the 10% oxalic acid etching test method for stainless steel. This standard is applicable to the screening test method for testing intergranular corrosion of austenitic stainless steel. After the specimen is electrolytically etched in a 10% oxalic acid solution, the metallographic structure of the etched surface is observed under a microscope to determine whether it is necessary to conduct long-term hot acid tests such as sulfuric acid and ferric sulfate, 65% nitric acid, nitric acid-hydrofluoric acid and sulfuric acid-copper sulfate. It can also be used as an independent intergranular corrosion test method when damage to the tested structural parts and equipment is not allowed. GB/T 4334.1-2000 Test method for 10% oxalic acid etching of stainless steel GB/T4334.1-2000 Standard download decompression password: www.bzxz.net

ICS 77. 040. 99
National Standard of the People's Republic of China
GB/T 4334.1—2000
Method of 10 per cent oxalic acid etch test for stainless steels2000-10-25Promulgated
Implementation on 2001-09-01
Promulgated by the State Administration of Quality and Technical Supervision
GB/T4334.1—2000
This standard is equivalent to the Japanese Industrial Standard JIS G0571-1980 "Method of 10 per cent oxalic acid etch test for stainless steel". It is basically the same as the Japanese standard in terms of scope of application, preparation of specimens, test solutions, test instruments and equipment, test conditions and procedures, and test results. Provisions on sampling of specimens and sensitization treatment of welded specimens have been added. This revision of the standard modifies the following provisions: Add Chapter 2 Reference Standards and Chapter 8 Test Report; Add 3.1.3 Requirements for Sampling of Welded Pipes;
The original 1.1.6 (now 3.1.6) has its contents adjusted; Cancel the original 1.2.3;
In the original 2-1 (now 5.1), the accuracy of the ammeter is specified; In the original Chapter 3 (now Chapter 6), 6.3 is added: --- Add the grade 1Cr18Ni9Ti to Table 4; The contents of the original Appendix A are put into the main text after adjustment. GB/T4334 includes the following parts:
GB/T4334.1 Stainless steel 10% oxalic acid etch test method GB/T4334.2 Stainless steel sulfuric acid-ferric sulfate corrosion test method GB/T4334.3 Stainless steel 65% nitric acid corrosion test method GB/T4334.4 Stainless steel nitric acid-hydrofluoric acid corrosion test method GB/T4334.5 Stainless steel sulfuric acid-sulfuric acid corrosion test method This standard replaces GB/T4334.1-1984 & Stainless steel 10% oxalic acid etch test method\ from the date of implementation. This standard is proposed by the State Metallurgical Industry Bureau. This standard is under the jurisdiction of the National Steel Standardization Technical Committee. The drafting units of this standard are: Metallurgical Industry Iron and Steel Research Institute, Hefei General Machinery Research Institute, Shanghai Wugang Group Corporation, Metallurgical Information Standards Research Institute.
The main drafters of this standard are Hu Xiaobai, Zhang Weituo, Lu Yonglin, Yanagisawa Xun, Zuo Weimin, and Wang Zaienyuan. This standard was first issued in April 1984.
1 Surface
National Standard of the People's Republic of China
Method of 10 per cent oxalic acid etch test for stainless steels
Method of 10 per cent oxalic acid etch test for stainless steelsGB/T 4334.1—2000
Replaces GE/T 4334.1—1984
This standard specifies the test specimens, test solutions, test equipment, test conditions and procedures, and the evaluation of test results and test reports for the 10% oxalic acid etch test method for stainless steels.
This standard is applicable to the screening test method for testing intergranular corrosion of austenitic stainless steels. After the sample is electrolytically etched in 10% oxalic acid solution, the metallographic structure of the etched surface is observed under a microscope to determine whether it is necessary to conduct long-term hot acid tests such as sulfuric acid-ferric sulfate, 65% nitric acid, nitric acid-hydrogen nitrogen acid, and sulfuric acid-copper sulfate. It can also be used as an independent intergranular corrosion test method when damage to the tested structural parts and equipment is not allowed. 2 Referenced standards
The clauses contained in the following standards constitute the clauses of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T655-1994 Chemical reagent ammonium persulfate GB/T2100-1980 Technical conditions for stainless acid-resistant steel castings GB/T 9854---1988 Chemical reagent oxalic acid 3 Test specimens
3.1 Sampling and preparation 1)
3.1.1 The samples of pressure-processed steel are sampled from the same furnace number, the same batch of heat treatment and the same specification of steel. 3.1.2 Casting samples are sampled from the test blocks poured from the same furnace number of molten steel in accordance with GB/T2100. For steels containing the stabilizing element titanium, samples are taken from the test blocks poured at the end of the furnace number. 3.1.3 The welded pipe samples are taken from the same heat treatment batch and the same specification of welded pipes. 3.1.4 The welded pipe samples are taken from the test blocks with the same steel material and welding process as the product. 3.1.5 The surface to be inspected is the service surface. The sample of the welded joint should include the surface of the parent metal, the heat affected zone and the weld metal. The cross section must be inspected when determining the pit structure.
3.1.6 The sampling method of the sample is generally sawing. If the shearing method is used, the affected part of the shearing should be removed by cutting or grinding.
3.1.7 The surface of the sample to be inspected should be polished to facilitate corrosion and microstructure inspection. 3.2 Sensitization of the sample
3.2.1 Before digitization and testing, the sample should be degreased and dried with an appropriate solvent or detergent (non-chloride). Adoption instructions:
1] Add 3.1.1 ~ 3.1.4 for pressure processing, castings, welded pipes and welding or sampling period. National Quality and Technical Supervision Approved on 2000-10-25 Implementation on 2001-09-01
GB/T4334.1-2000
3.2.2 The sensitization treatment of the sample is carried out before ground light. For ultra-low carbon steel (carbon content not more than D.口3%) and stabilized steel (added titanium or niobium, the sensitization treatment system is 650℃, the pressure processing sample is kept warm for 2 hours, and the casting is kept warm for 1 hour. h, air cooling. 3.2.3-1 The welded specimens are tested directly in the post-weld state. For the joints that are to be subjected to heat treatment above 350°C after welding, the specimens shall also be subjected to chemical treatment after welding. The chemical treatment system shall be specified separately in the agreement. 4 Test solution
4.1. Special 10D=Superior pure oxalic acid that complies with GB/T9854 is dissolved in 900mL of distilled water or deionized water to prepare a 10% oxalic acid solution.
4.2 For molybdenum-containing steels where it is difficult to have a step structure, 100% ammonium persulfate that complies with GB/T655 analytical purity can be dissolved in 900mL of distilled water or deionized water to prepare a 10% ammonium persulfate solution instead of the 10% oxalic acid solution. 5 Test instruments and equipment
5. 1 DC power supply, variable resistor, and ammeter with appropriate range (accuracy 0.5 5-2 The cathode is a steel cup made of austenitic stainless steel or a stainless steel sheet with a large enough surface area, and the anode is the sample. If a steel sheet is used as the cathode, a fixture of appropriate shape should be used to keep the sample in the test liquid. The immersion circuit is shown in Figure 1. Large samples are used for
b Small samples are used for
Acid-resistant sample cavity enclosure-
No acid-resistant components
1-stainless steel container; 2-sample: 3-liquid power supply; 4-transformer 5-current rate; F-switch Figure 1 Electrolytic device and diagram
6 Test conditions and steps
6. 1 Use the etched sample as the anode + pour 10% oxalic acid solution, use the stainless steel cup or stainless steel sheet as the cathode, and turn on the current. The current density is the use of instructions,
Add 3.2.3 provisions for welding or sample dispersion treatment. 2
GB/T 4334.1—2000
1A/cm, immersion time 90s, immersion dissolution temperature 20℃～50℃6. 1. 1 When soaked with 10% ammonium persulfate, the current density is 1 A/cm\, and the etching time is 5 min~10 min. 6-2 After the sample is etched, wash it with running water and dry it. Observe the entire etched surface of the sample under a metallographic microscope with a magnification of 200 times to 500 times, and determine the type of organization according to Table 1, Table 2 and Figures 2-8. 6.3 Use a new solution for each test.
Classification of diffuse etching organization
The classification of etched organization showing grain boundary morphology is shown in Table 1. The classification of etched organization showing pit morphology is shown in Table 2. The relationship between the screening test and other test methods is shown in Table 3 and Table 4. Table 1 Classification of grain boundary morphology
Stepped structure
Mixed structure
Muffled structure
Dense high-deficient structure
Continuous groove structure
Pit structure 1
Pit structure I
Specimen category
Organization category
Organization characteristics
There is no corrosion at the grain boundary, and the grains are stepped. See Figure 2. There are shoulder grooves at the grain boundary.But there is one grain surrounded by corrosion grooves. See Figure 3. There are corrosion grooves at the grain boundary: Some grains are surrounded by corrosion grooves. See Figure 4. Casting and welded joints. The grain boundary has no corrosion grooves. The ferrite is revealed. See Figure 5. Steel parts and welded joints. The uniform structure is very deep and forms a chain groove structure. See Figure 6. Table 2. Classification of pit morphology
Group characteristics
Structure with many shallow pits and few exploratory pits. See Figure 7. Structure with few shallow pits and many deep pits. See Figure 8 Table 3 Relationship between selected tests and other test methods Pressure processing specimen
Sulfuric acid-sulfuric acid 65% nitric acid Sulfuric acid-sulfuric acid
Nitric acid-hydrogen
Wide trace test Etching test
Test method
Iron corrosion test
Test method
Acid corrosion test
Test method
Note: Means and must be tested by other methods (center) means that other methods must be tested Casting, welding specimens | |tt||65% nitric acid sulfuric acid-sulfuric acid nitric acid-hydrogen fluoride
sulfuric acid-sulfuric acid
copper court etching test
test method
lesion etching or test
recovery tumor etching test acid liver etching test
test method
test method
hot aldehyde test
sulfuric acid-acid-resistant titanium test
65% nitric acid test
acid hydrochloric acid test
sulfuric acid-sulfuric acid steel test!
Instructions for use:
GB/T 4334.1—2000
Table 41 Relationship between oxalic acid etch test and hot acid test Use 10% acid resistance test to determine whether hot acid test is required for stainless steel types
CTIEnig,GeCrIeniIo
GCr:7N12M02, 00C117N14M02
r1HN12M2Cu2
UtCrt8Ni11M:2Cu2
fICr19Ni13Mo3,00Cr19Ni13Mo3
Cr18Ni9. 00C+19N:1C
：0Cr17Ni12Mu2.00C17N/14M2
Cr18Ni12Mo2Cu2
00Cr18Ni14Mo2Cu2
UCr19Ni13M o3,0G1Ni13Mo3
(Cr18Ni9,GUCr1SNil0
0Cr17N112Mo2,00Cr17Ni11Mo2
0Cr18N13Mo2at2
OOC -TXNitAMe2Cu2.UG-1SNi1SMe300Cr19Ni13M3.r18Ni1i
uCr18Ni11N5,JCr18Ni9Ti
OCINNJCTI
11Table 4 The sulfuric acid-sulfuric acid test is to add 1Cr18Ni9Ti to the hot acid test to check the magnetized material or the stainless steel. The relationship between the phase and the type of stainless steel is as follows: Cast carbide: 0Cr18Ni9, 0Xr19Ni10 (Cr17Ni12Mo2.G0Cr17Ni14Mo2) r18Ni12Mo2Cu2.00Cr18Ni14Mo2Cu2oCr19Ni13M3,C 0Cr19Ni13Me3
Chromium carbide and agent:
(rSNilTi
Chromium magnet:bzxZ.net
(Cr18Ni9,(UCI19N:10
Chromium decomposition and phase:
0Cri18.Ni12Mo2Cu2,c0Cr18Ni14Mo2Cu200C:r17N14M2,0r17Ni12Ma2
Cr19 Ni13Mo3.0(Cr19Ni13Mo3.cCr15Ni10TiMr1BNiiNh
Chromium carbide,
0Cr17Nil2Mo2.@0Cr17Ni14Mo2
Cr18Ni12Mo2Cu2,00Cr18Ni14M2Cu2cCr19Ni13Mo3,60Cr19Ni13Mo3
Lattice carbide:||tt ||:oCr18.Ni9.00Cr19NJ0,0C17Ni12Mo200Ct17Ni14Mo2.0Ct18Ni12M2Cu200Cr18Ni14Mo2Cu2,6Cr19Ni13vio300C-19N:13M>3,0C-18Ni10Ti
00C118Ni11Nb,1C+18Ni9Ti,OCr18NEI0TjGB/T 4334.1—2000
Figure 2 Step organization (
Type) × 500
Figure 3 Mixed organization (Type II) × 500)
GH/T 4334. 1- 2000
Figure 4 Groove structure (type III) × 500
Helical iron body structure (type IV) × 25C
GB/T4334:1-2000
Figure 5 Continuous groove structure (type V) × 250Figure 7 Pit structure (type VI) × 500
8 Test report
The test report should include the following:
a) Name of the sample and test area size; b) Current density; c) Etching time and temperature; d) Metallographic photos after etching; c) Judgment result.
GB/T 4334.1--2000
Figure 8 Pit group level (type VII) × 5000Xr19Ni10
(Cr17Ni12Mo2.G0Cr17Ni14Mo2
r18Ni12Mo2Cu2.00Cr18Ni14Mo2Cu2oCr19Ni13M3,C0Cr19Ni13Me3
Chromium carbides and agents:
(rSNilTi
Chromium magnets:
(Cr18Ni9,(UCI19N:10
Chromium decomposition and phases:
0Cri18.Ni12Mo2Cu2,c0Cr18Ni14Mo2Cu200C:r17N14M2,0r17Ni12Ma2
Cr19Ni13Mo3.0(Cr19Ni13Mo3.cCr15Ni10TiMr1 BNiiNh
Chromium carbide,
0Cr17Nil2Mo2.@0Cr17Ni14Mo2
Cr18Ni12Mo2Cu2,00Cr18Ni14M2Cu2cCr19Ni13Mo3,60Cr19Ni13Mo3
Lattice carbide:
:oCr18.Ni9.00Cr19NJ0,0C17Ni12Mo200Ct17Ni14Mo2.0Ct18Ni12M2Cu200Cr18Ni14Mo2Cu2,6Cr19Ni13vio300C-19N:13M>3,0C-18Ni10Ti
00C118Ni11Nb,1C+18Ni9Ti,OCr18NEI0TjGB/T 4334.1—2000
Figure 2 Ladder organization (
Class) × 500
Figure 3 Mixed organization (Class II) × 500)
GH/T 4334.1- 2000
Figure 4 Groove structure (type III) × 500
Helical iron body structure (type IV) × 25C
GB/T4334:1-2000
Figure 5 Continuous groove structure (type V) × 250Figure 7 Pit structure (type VI) × 500
8 Test report
The test report should include the following:
a) Name of the sample and test area size; b) Current density; c) Etching time and temperature; d) Metallographic photos after etching; c) Judgment result.
GB/T 4334.1--2000
Figure 8 Pit group level (type VII) × 5000Xr19Ni10
(Cr17Ni12Mo2.G0Cr17Ni14Mo2
r18Ni12Mo2Cu2.00Cr18Ni14Mo2Cu2oCr19Ni13M3,C0Cr19Ni13Me3
Chromium carbides and agents:
(rSNilTi
Chromium magnets:
(Cr18Ni9,(UCI19N:10
Chromium decomposition and phases:
0Cri18.Ni12Mo2Cu2,c0Cr18Ni14Mo2Cu200C:r17N14M2,0r17Ni12Ma2
Cr19Ni13Mo3.0(Cr19Ni13Mo3.cCr15Ni10TiMr1 BNiiNh
Chromium carbide,
0Cr17Nil2Mo2.@0Cr17Ni14Mo2
Cr18Ni12Mo2Cu2,00Cr18Ni14M2Cu2cCr19Ni13Mo3,60Cr19Ni13Mo3
Lattice carbide:
:oCr18.Ni9.00Cr19NJ0,0C17Ni12Mo200Ct17Ni14Mo2.0Ct18Ni12M2Cu200Cr18Ni14Mo2Cu2,6Cr19Ni13vio300C-19N:13M>3,0C-18Ni10Ti
00C118Ni11Nb,1C+18Ni9Ti,OCr18NEI0TjGB/T 4334.1—2000
Figure 2 Ladder organization (
Class) × 500
Figure 3 Mixed organization (Class II) × 500)
GH/T 4334.1- 2000
Figure 4 Groove structure (type III) × 500
Helical iron body structure (type IV) × 25C
GB/T4334:1-2000
Figure 5 Continuous groove structure (type V) × 250Figure 7 Pit structure (type VI) × 500
8 Test report
The test report should include the following:
a) Name of the sample and test area size; b) Current density; c) Etching time and temperature; d) Metallographic photos after etching; c) Judgment result.
GB/T 4334.1--2000
Figure 8 Pit group level (type VII) × 500
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