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welde steel pipe line
Nov 30, 2018

                                                           Straight seam welded pipe technology
According to the standard of GB/T3092 "welded steel pipe for low-pressure fluid transportation", the nominal diameter of the welded pipe is 6~150mm, the nominal wall thickness is 2.0~6.0mm, and the length of the welded pipe is usually 4~10m, which can be fixed or doubled. The length of the ruler is factory. The surface quality of the steel pipe should be smooth, and defects such as folding, cracking, delamination and lap welding are not allowed. The surface of the steel pipe is allowed to have slight defects such as scribes, scratches, misalignment of the weld, burns and scars that do not exceed the negative deviation of the wall thickness. Allows thickening of the wall thickness at the weld and the presence of internal weld beads.
                                                            Quality inspection
Welded steel pipes shall be subjected to mechanical performance tests, flattening tests and flare tests, and shall meet the requirements specified in the standard. The steel pipe should be able to withstand a certain internal pressure, and if necessary, carry out a pressure test of 2.5Mpa to maintain no leakage for one minute. It is allowed to replace the hydrostatic test by means of eddy current testing. Eddy current testing is carried out according to GB7735 "Steel Flow Test Method for Steel Tubes". The eddy current testing method is to fix the probe on the frame, and the flaw detection and the weld seam are kept at a distance of 3~5mm. The weld is fully scanned by the rapid movement of the steel pipe, and the flaw detection signal is automatically processed and automatically sorted by the eddy current flaw detector. To achieve the purpose of testing. The welded pipe after the flaw detection is cut with a flying saw according to the specified length, and is turned off the frame by the flip frame. Both ends of the steel pipe should be chamfered with flat heads, printed with marks, and the finished pipe is wrapped with hexagonal packaging and shipped.

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