High Grade Spiral Steel Pipe Product Quality Priority

High-grade spiral steel pipe manufacturers always adhere to product quality and reliable

High-grade spiral steel pipe manufacturers always adhere to product quality priority, the recent steel market has been in a state of instability, prices fluctuated, in the face of such a phenomenon, we manufacturers to make corresponding countermeasures, high-grade spiral steel pipe production to go through A variety of processes, each process must undergo a rigorous inspection, the factory must pass the test to the factory, the only way we produce steel pipe in the market is the protagonist has been.

High-grade spiral steel pipe is based on strip coil as raw material, often temperature extrusion molding, automatic double wire double-sided submerged arc welding process welded seam steel pipe. The use of advanced double-sided submerged arc welding process, can be achieved in the best location of welding, not prone to wrong side, welding and not welding and other defects, easy to control the quality of welding.

High-grade spiral steel pipe in the factory should do before the mechanical performance test and flattening test and flaring test, and to meet the requirements of the standard requirements. Straight seam steel pipe quality testing methods are as follows:

1, from the surface to judge, that is, in the appearance of inspection. The appearance of the welded joint inspection is a simple procedure and a wide range of inspection methods, is an important part of the finished product inspection, mainly to find the weld surface defects and size of the deviation. Generally through the naked eye observation, with the standard model, gauge and magnifying glass and other tools for testing. If there is a defect on the surface of the weld, there may be a defect in the weld.

2, the physical method of inspection: the physical test method is the use of some physical phenomena for the determination or testing methods. Materials or parts of the internal defects of the inspection, are generally used non-destructive testing methods. Non-destructive testing of ultrasonic testing, ray detection, penetration testing, magnetic detection and so on.

3, the strength of the pressure vessel test: pressure vessel, in addition to sealing test, but also for strength test. Commonly there are two kinds of hydraulic pressure test and air pressure test. They are able to test the weld densities of containers and pipes working under pressure. Pneumatic test is more sensitive and faster than hydraulic pressure test, while the product after the test without drainage, especially for difficult drainage products. But the risk of testing than the hydraulic test. During the test, the corresponding safety and technical measures must be observed to prevent accidents during the test.

4, compactness test: the storage of liquid or gas welding containers, the weld is not dense defects, such as penetrating cracks, pores, slag, not penetration and loose tissue, etc., can be used to find the compact test. Densification test methods are: kerosene test, water test, water test and so on.

5, hydrostatic test Each steel pipe should be hydrostatic test without leakage phenomenon, the test pressure by the test P = 2ST / D where the S-hydrostatic test test stress Mpa, hydrostatic test test stress by the corresponding The strip standard specifies 60% of the minimum yield (Q235 235Mpa). D = 508 test pressure holding time of not less than 5 seconds; D ≥ 508 test pressure holding time of not less than 10 seconds 4 non-destructive testing of steel pipe welding seam, steel strip on the head weld and ring joints should be carried out X-ray or ultrasonic inspection. For helical welds of steel for combustible ordinary fluid delivery, a 100% SX-ray or ultrasonic test shall be carried out. The spiral welds of steel pipes for general fluid delivery such as water, sewage, air, heating steam shall be subjected to X-ray or Ultrasonic examination checks (20%).