The quality inspection method of lsaw steel pipe
is as follows:
1, Judging from the surface, that is, in appearance inspection. The appearance inspection of welded joints is a simple and widely used inspection method. It is an important part of the inspection of finished products. It mainly finds the defects on the weld surface and the deviation in dimensions. It is usually visually inspected and tested with tools such as standard templates, gauges, and magnifiers. If the weld surface defects, there may be defects inside the weld.
2. Physical method inspection: The physical inspection method is a method that uses some physical phenomena to measure or test. Inspection of defects in materials or workpieces is generally performed by means of non-destructive testing. Non-destructive testing includes ultrasonic testing, ray testing, penetrant testing, and magnetic testing.
3, The strength of the pressure vessel inspection: pressure vessel, in addition to the sealing test, but also for strength testing. There are two kinds of pressure test and pressure test. They all test the tightness of welds in vessels and pipes that work under pressure. The air pressure test is more sensitive and quicker than the water pressure test. At the same time, the product after the test does not need to be drained. This is especially true for products that are difficult to drain. Be applicable. However, the test is more dangerous than the hydrostatic test. When carrying out tests, corresponding safety measures must be observed to prevent accidents during the test.
4. Test for compactness: For welding vessels that store liquids or gases, the non-dense weld defects, such as penetrating cracks, pores, slag inclusions, incomplete penetration, and loose structures, can be detected by the compactness test. Denseness test methods include: kerosene test, water load test, water test, etc.
5, Hydrostatic test each pipe should be done hydrostatic pressure test without leakage phenomenon, the test pressure to calculate the test pressure P = 2ST/D type S to hydrostatic pressure test stress Mpa, the test stress of the hydrostatic test corresponding the steel strip standard specifies 60% of the minimum yield (Q235 is 235Mpa). Regulatory time: D <508 test pressure retention time of not less than 5 seconds; D ≥ 508 test pressure to maintain time of not less than 10 seconds 4 Non-destructive testing Pipe repair welding, strip-to-head welding and circumferential joints should be X-ray or ultrasonic inspection. Spiral welds for the transport of flammable ordinary fluids shall be subjected to 100% SX-ray or ultrasonic inspection. Spiral welds used for steel, such as water, sewage, air, and heating steam, shall be subjected to X-ray or Ultrasonic inspection spot checks (20%).