CB/T 3949-2001 Test method for intergranular corrosion of marine stainless steel welded joints CB/T3949-2001 Standard download decompression password: www.bzxz.net

1c5 47.020.05
Registration No.: B44-2002
Ship Industry Standard of the People's Republic of China
CB/T 3949-2001
Method of intergranular corrosion test of welding joint of stainless steels for hull structure2((11 — 11 —15 Issued
National Defense Science, Technology and Industry Commission Issued
2002—2—0] Implemented
CB/T 3949-2001
This standard is based on the requirements of the National Forging Society Materials and Sources Standard 3 (1998). It is based on 150651.2:1996 Standard for Stainless Steels - Determination of Total Acidity - Part 2: Test Method for the Containing of Acetic Acid in a Medium (Oyperstrsstes et al.)
This standard is different from the international standard: for the increase of the sample selection, the sample is scanned before the test, the cold change point is not supported for the whole day test, etc.||tt| |This standard is proposed by China's national standardization technical committee for materials, processes and products! . The drafting units of this standard are: Jiangsheng Equipment Institute, Jiwang Co., Ltd., Jiangyang Shipyard Industry Comprehensive Technology Research Institute and Wuzhi Avoid Good Factory
Xiao Ning Who is the main person in charge: Wu Jing, Luo Erchen, Qiu, Dehui. 1Fan Guo
BT3949-2001
Intergranular corrosion test method for marine stainless steel welded joints This standard is regarded as the protection of The test method for stainless steel joints is to test the sample, test equipment, test steps, test depth and test report.
This standard is applicable to the hot edge stainless steel welded joints in copper sulfate acid solution with a towel shoulder. 2 References to the standard
The following standards contain clauses, which constitute the provisions of this standard through reference in this standard. All standards will be revised when the version shown is valid: All parties using this standard should consider using the following standard new version: CE/ 7467-1997 Ceramic Material
, 26-18 Chemical Acid
EB/T665-1966 Chemical Test Rate: Sulfuric Acid Material Preparation and Sample Connection Specification
3 Test Specimen
3.1 Selection of Test Specimen
1998 China Classification Society
3.1.1 The material should be selected from the same test material as the product parent material, welding material and welding process. The material should be selected according to the relevant provisions of the welding standard or other relevant technical requirements: 31.? The shaped test specimens are cut according to Figure 1 or Figure 2. 3.1.3 Tubular test specimens are cut according to Figure 2 or Figure 4. When the outer diameter is less than 0m, the test section is obtained. When the outer diameter is greater than 40, the test specimen is cut into a bed shape. The length of the test specimen is not less than 50m and the width is not less than 21m. Figure 1: Sample drawing of flat butt joint specimen
Test drawing
Figure 3: Sampling drawing of pipe joint specimen
Pre-sampling drawing
Sampling of flat cross joint specimen
Sampling drawing
4: Sampling of pipe longitudinal specimen
CBT 3919-2001
3.1.4 When the specimen thickness is 6mn, the maximum thickness of the specimen is 6ul, and one oxygen surface is reserved, which is the surface in contact with the medium and also serves as the tensile surface of the test.
3.1.5 Take 1-2 test pieces for each sample. 3.2.3.2. The test pieces shall be cut by machine. The parts affected by shearing or heat shall be removed by single stroke or hot cutting. The lower surface of the welded chain shall be machined flush with the surface of the material.
3.2.2. If the sample has sensitized skin, it shall be removed by cutting. If the surface of the bottom of the test rod is sensitized, it shall be ground after sensitization. 3.2.3. When grinding, the test piece shall be free from overheating. The test surface shall be ground with a 11-day non-titanium wire. The torsion dryness of the test surface shall be less than 0.8.
3.2.4. The test piece shall be sealed with an appropriate cleaning agent or cleaning agent. (Non-chemical: remove oil from the medium, then wash and 10 times. 3.2.5 When grinding is not possible, a solution made of raw material, nitric acid and distilled water in a ratio of 10:1:10 can be used for washing. The solution should be made of a solution of nitric acid and distilled water in a ratio of 1:1. The solution should be cleaned in a steam room. The cleaning time should not be too long. 3.3 Sensitization treatment of samples
The welded samples are tested directly in the post-explosion state. For the joints that have been heated for more than 350° after scanning, the samples should be treated in time after welding. The sensitization treatment system is not completed separately in the test room. 4 Test device
The test device should be a hot device that can keep the test liquid in a slightly boiling state and a 100° hot water per minute air flow rate. ~ Center with reflux condenser potential chain chart Figure 5.
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Cold frequency health
Flush water (in)www.bzxz.net
Medium heat device
Figure 5 Test equipment five schematic group
5 Test steps
5 Put the acid in the distilled water, bowl, use the system to make the test liquid: before the acid flow, it should be combined/-5: the system requirements are uniform, the acid flow T625 is divided into pure requirements 5.2 does not reduce the core part of the store is to eliminate: the huge should be based on the requirements of the certificate 7. Put the hundred reading selection, the big result certificate pulls the real single and the two are connected, the specification bottle can be filled with the parent material and the sample can be placed according to the material group: before the flow, the two are required to be in contact with each other. 2
CB/T 3949--2001
5.3 The ratio of the micro-test solution to the total test solution should be at least 3/3. Each test should be conducted with a freshly prepared solution. If necessary, the solution can be washed with warm water and reused.
5.4 Place the boiling water in a heating device and heat it, and then pass cold water through it. Boil until the solution reaches 2 liters and start timing. It should also be maintained for 20 seconds before boiling. E: If there is any dispute over the test results, take 20 seconds before boiling. Within the specified time, the sample must 5.5 After the test, the sample should be cleaned, polished and subjected to a complete test: 6 Evaluation of test results 6.1 The corrosion test results of the joints should be evaluated by practical tests or pressure tests. 6.2 When testing the joints and the internal MW samples, the bending line should be perpendicular to the goodness. For the flat cross joint test, the test line should be parallel to the welding direction of the weld. The test should be carried out at room temperature. The bending core diameter of the test should be twice the thickness of the specimen, and the bending angle is 90″:
6.3 When the pipe is flattened by half, the distance between the two half surfaces is measured under small load: the value is calculated using formula (1) _1.090-
In which: - The distance between the upper and lower surfaces of the flat specimen is: - The outer diameter, mm:
- The wall thickness of the specimen, m
, 4 Use a 10x magnifying glass to observe whether the specimen has any defects on the surface after the two bends. Cracks produced at the bottom of the sample, cracks produced at the corners of the sample bending part, cracks that are not connected, surface cracks, etc., are not determined to be crystal-clear. Stone.5 If the results of some of the "effective time" on the bent sample are found, the original test sample can be re-attacked according to the market preparation method and then the two samples can be compared to determine whether the corrosion effect is sufficient. For cracks that are difficult to determine, the metallographic method can be omitted for evaluation. Take a metallographic sample from the cracked sample and observe the corrosion depth under a microscope for 5 to 50 seconds. If the corrosion depth is not deep, the corrosion depth can be determined. The test report should include the following: 1) the brand and specifications of the parent material and welding material; 2) welding process; 3) evaluation test method and quality test results; 4) when the gold method is used, the intergranular corrosion test value should be recorded;
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