In practical applications, we can use welded pipes to transport various low-pressure fluids. This product is generally made of Q195, Q215A, Q235A steel, and Q235B ordinary carbon. It can also be manufactured together with easy-to-weld 0317 standard model 6012 and steel mother 755 mild steel. After the production of the welded pipe is completed, it is necessary to carry out experiments such as hydraulic pressure, bending, and flattening, and there are also certain requirements for its surface quality.

At the same time, the length and diameter of the welded pipe should also meet the requirements of practical applications. According to its wall thickness, it can be divided into two types: ordinary steel pipe and thickened steel pipe. Among them, the common submerged arc welding straight seam steel pipe adopts submerged arc welding technology, which uses filler welding and particle protection flux submerged arc. The diameter of production can reach 1500 mm, and the production technology of submerged arc welding straight seam steel pipe includes JCOE forming technology and rolling forming submerged arc welding technology. That is to say, with the continuous improvement of production level, the production quality and process level of various welded pipes have also been improved. So what are the specific steps when it is accepted?

First of all, straight-seam steel pipes should be submitted for acceptance in batches, and the batching rules should comply with the provisions of the corresponding product standards.

Secondly, during the inspection process of welded pipes, the inspection items, sampling quantity, sampling location, and test method shall be in accordance with the provisions of the corresponding product standards. With the consent of the purchaser, hot-rolled seamless straight-seam steel pipes can be sampled in batches according to the number of rolling roots. When analyzing the test results, if a certain item does not meet the requirements of the product standard, the unqualified ones should be picked out, and double the number of samples should be randomly taken from the same batch of straight seam steel pipes for different tests. Re-inspection of qualified items. If the re-inspection result (including any index required by the project test) is unqualified, the batch of straight-seam steel pipes shall not be delivered.

If the re-inspection results still fail, then the welded pipes need to be inspected one by one or re-heat-treated (the number of re-heat-treatments should not exceed twice), and a new batch should be submitted for acceptance. If there is no special regulation in the product standard, the chemical composition of the welded pipe shall be checked and accepted according to the melting composition.