What aspects are generally involved in the factory inspection of stainless steel seamless elbows?
The stainless steel seamless elbow must pass the corresponding inspection when it is manufactured and packaged before leaving the factory, and it can only leave the factory after passing the test. Therefore, Licheng Steel will tell you what aspects are involved in the detection of stainless steel seamless elbows?
1. Visual inspection
Check the appearance of stainless steel seamless elbows one by one. The surface must be smooth and free of scale, there must be no pipe fittings greater than 5% of the nominal wall thickness, and there must be no obvious defects such as scars, folds, and separation layers with a maximum depth of more than 0.8mm. Mechanical scratches greater than 12% of the nominal wall thickness and with a maximum depth less than 1.6mm should be removed.
2. Size inspection
The size of the stainless steel seamless elbow must meet the standard. Use a vernier caliper to measure, check with the corresponding standard inspection table, check the shape and size of the stainless steel seamless elbow one by one, the shape tolerance does not exceed the national standard GB/T12459-2005, the minimum wall thickness of the stainless steel seamless elbow is not less than the nominal wall thickness 87.5% of the thickness, that is, the thinning of the doll is not more than 12.5%.
3. Hardness testing
The hardness test of stainless steel seamless elbows must comply with the corresponding national standards. For carbon steel elbows, 3% of each batch is drawn, and at least two pieces are tested for hardness. If there are unqualified products, they cannot be shipped from the factory and double-checked. If they are still unqualified, heat treatment should be carried out again. After inspection, it is approved to leave the factory, and the hardness of the carbon steel elbow shall not exceed 156HB at most.
4. End bevel of elbow pipe fittings
Since most stainless steel seamless elbow pipe fittings are connected by welding, in order to improve the welding quality, the end faces of the elbows are all machined into grooves. Leave a certain angle, with a certain edge, and the edge thickness bevel angle must be within the fixed deviation range.
5. Supplementary inspection
For some stainless steel seamless elbows with special requirements, low temperature toughness impact testing, non-destructive testing of elbow fittings, magnetic particle inspection and some mechanical tests should also be carried out. For details, refer to GB/T12459-2005 or the supplier’s material quality inspection report and quality assurance certificate; the material can refer to the quality assurance certificate or inspection report provided by the supplier; for special materials, sampling and testing are required.
6. Logo content
Manufacturer’s name, trademark, material grade, and nominal size, wall thickness grade, product code, standard number, etc.
7. Logo position
As long as the specification permits, there are standards on the tube. It should be marked near the centerline of the side of the stainless steel seamless elbow, and the mark is best in a position that is easy to observe. Stamps should avoid high stress areas of pipe fittings.
What aspects are generally involved in the factory inspection of stainless steel seamless elbows?
The stainless steel seamless elbow must pass the corresponding inspection when it is manufactured and packaged before leaving the factory, and it can only leave the factory after passing the test. Therefore, Licheng Steel will tell you what aspects are involved in the detection of stainless steel seamless elbows?
1. Visual inspection
Check the appearance of stainless steel seamless elbows one by one. The surface must be smooth and free of scale, there must be no pipe fittings greater than 5% of the nominal wall thickness, and there must be no obvious defects such as scars, folds, and separation layers with a maximum depth of more than 0.8mm. Mechanical scratches greater than 12% of the nominal wall thickness and with a maximum depth less than 1.6mm should be removed.
2. Size inspection
The size of the stainless steel seamless elbow must meet the standard. Use a vernier caliper to measure, check with the corresponding standard inspection table, check the shape and size of the stainless steel seamless elbow one by one, the shape tolerance does not exceed the national standard GB/T12459-2005, the minimum wall thickness of the stainless steel seamless elbow is not less than the nominal wall thickness 87.5% of the thickness, that is, the thinning of the doll is not more than 12.5%.
3. Hardness testing
The hardness test of stainless steel seamless elbows must comply with the corresponding national standards. For carbon steel elbows, 3% of each batch is drawn, and at least two pieces are tested for hardness. If there are unqualified products, they cannot be shipped from the factory and double-checked. If they are still unqualified, heat treatment should be carried out again. After inspection, it is approved to leave the factory, and the hardness of the carbon steel elbow shall not exceed 156HB at most.
4. End bevel of elbow pipe fittings
Since most stainless steel seamless elbow pipe fittings are connected by welding, in order to improve the welding quality, the end faces of the elbows are all machined into grooves. Leave a certain angle, with a certain edge, and the edge thickness bevel angle must be within the fixed deviation range.
5. Supplementary inspection
For some stainless steel seamless elbows with special requirements, low temperature toughness impact testing, non-destructive testing of elbow fittings, magnetic particle inspection and some mechanical tests should also be carried out. For details, refer to GB/T12459-2005 or the supplier’s material quality inspection report and quality assurance certificate; the material can refer to the quality assurance certificate or inspection report provided by the supplier; for special materials, sampling and testing are required.
6. Logo content
Manufacturer’s name, trademark, material grade, and nominal size, wall thickness grade, product code, standard number, etc.
7. Logo position
As long as the specification permits, there are standards on the tube. It should be marked near the centerline of the side of the stainless steel seamless elbow, and the mark is best in a position that is easy to observe. Stamps should avoid high stress areas of pipe fittings.