Where are the factory inspections of stainless steel seamless elbows checked?
The factory inspection of stainless steel seamless elbows is very important. If the inspection results fail, they cannot leave the factory and need to be carried out again.
The detection of stainless steel seamless elbows is generally carried out from the following aspects:
1. Visual inspection
The appearance of stainless steel seamless elbows needs to be checked one by one. The surface of the pipe fittings should be smooth and free of scale, and there should be no obvious defects such as scarring, folding and separation layer > 5% of the nominal wall thickness and the maximum depth ≤ 0.8mm. The nominal wall thickness is 100%. Twelve mechanical scratches with a maximum depth of ≤1.6mm must be removed.
2. Check the size
Use a vernier caliper to measure stainless steel products that meet the corresponding standards, and then check with the corresponding standard inspection table. Note: Check the shape and size of stainless steel seamless elbows one by one. The shape tolerance does not exceed the national standard GB/T12459-2005. The minimum wall thickness of the elbow is not less than 87.5% of the wall thickness, that is, the thickness of the elbow is not more than 12.5%.
3. Testing hardness
The hardness test of stainless steel seamless elbows should comply with the corresponding national standards. For carbon steel elbows, 3% of each batch should be sampled, and the hardness of at least two products should be tested. If it is qualified, heat treatment should be carried out again, and the factory can only be allowed to leave the factory after being checked one by one and passing the test. The maximum hardness of the carbon steel elbow should not exceed 156HB.
4. End bevel
Because stainless steel seamless elbows are mostly used for welding connections, in order to improve the welding quality, the end faces of stainless steel seamless elbows should be grooved, leaving a certain angle, a certain side, and the angle of the groove must be within the specified within the range of deviation.
5. Supplementary inspection
Supplementary inspection For some stainless steel seamless elbows with special requirements, low temperature toughness impact testing, nondestructive testing of elbow fittings, magnetic particle testing and some mechanical tests are required. For specific data, refer to GB/T12459-2005 or the supplier’s material quality inspection report and quality assurance certificate. For the material of elbow fittings, please refer to the quality assurance certificate and test report provided by the supplier. Sampling must be carried out for special materials.
6. Logo content
Manufacturing trademark, product name, material grade, nominal size, wall thickness grade, product code and standard number, etc.
7. Logo position
If the specification permits, it should be marked on the stainless steel seamless elbow pipe fittings. The marking should be near the centerline of the side of the pipe fittings, and it should be in a position that is easy to observe. The steel stamp should avoid the high stress area of the pipe fittings.
Where are the factory inspections of stainless steel seamless elbows checked?
The factory inspection of stainless steel seamless elbows is very important. If the inspection results fail, they cannot leave the factory and need to be carried out again.
The detection of stainless steel seamless elbows is generally carried out from the following aspects:
1. Visual inspection
The appearance of stainless steel seamless elbows needs to be checked one by one. The surface of the pipe fittings should be smooth and free of scale, and there should be no obvious defects such as scarring, folding and separation layer > 5% of the nominal wall thickness and the maximum depth ≤ 0.8mm. The nominal wall thickness is 100%. Twelve mechanical scratches with a maximum depth of ≤1.6mm must be removed.
2. Check the size
Use a vernier caliper to measure stainless steel products that meet the corresponding standards, and then check with the corresponding standard inspection table. Note: Check the shape and size of stainless steel seamless elbows one by one. The shape tolerance does not exceed the national standard GB/T12459-2005. The minimum wall thickness of the elbow is not less than 87.5% of the wall thickness, that is, the thickness of the elbow is not more than 12.5%.
3. Testing hardness
The hardness test of stainless steel seamless elbows should comply with the corresponding national standards. For carbon steel elbows, 3% of each batch should be sampled, and the hardness of at least two products should be tested. If it is qualified, heat treatment should be carried out again, and the factory can only be allowed to leave the factory after being checked one by one and passing the test. The maximum hardness of the carbon steel elbow should not exceed 156HB.
4. End bevel
Because stainless steel seamless elbows are mostly used for welding connections, in order to improve the welding quality, the end faces of stainless steel seamless elbows should be grooved, leaving a certain angle, a certain side, and the angle of the groove must be within the specified within the range of deviation.
5. Supplementary inspection
Supplementary inspection For some stainless steel seamless elbows with special requirements, low temperature toughness impact testing, nondestructive testing of elbow fittings, magnetic particle testing and some mechanical tests are required. For specific data, refer to GB/T12459-2005 or the supplier’s material quality inspection report and quality assurance certificate. For the material of elbow fittings, please refer to the quality assurance certificate and test report provided by the supplier. Sampling must be carried out for special materials.
6. Logo content
Manufacturing trademark, product name, material grade, nominal size, wall thickness grade, product code and standard number, etc.
7. Logo position
If the specification permits, it should be marked on the stainless steel seamless elbow pipe fittings. The marking should be near the centerline of the side of the pipe fittings, and it should be in a position that is easy to observe. The steel stamp should avoid the high stress area of the pipe fittings.