Spiral steel pipe in the factory should be done before the mechanical performance test and flattening test and flaring test, and to meet the standards requirements. Spiral steel pipe quality testing methods are as follows:
1, From the surface to determine, that is, the appearance of inspection. The appearance inspection of welded joints is a simple and widely used inspection method. It is an important content of finished product inspection. It is mainly to find the defects of the weld surface and the deviation of the dimension. Generally through the naked eye, with the help of standard templates, gauges and magnifying glass and other tools for testing. If the weld surface defects, there will be defects within the weld may be.
2, The physical method of test: the physical test method is to use some physical phenomena to measure or test method. Materials or parts of the internal defects of the inspection, are generally used nondestructive testing methods. Nondestructive testing with ultrasonic testing, ray detection, penetration testing, magnetic testing and so on.
3, The pressure vessel strength test: pressure vessels, in addition to sealing test, but also for strength testing. Commonly there are two kinds of water pressure test and air pressure test. They are able to verify the tightness of the welds of vessels and piping operating under pressure. The pressure test is more sensitive and faster than the water pressure test. At the same time, the products after the test do not have drainage treatment, which is especially suitable for products with difficulty in drainage. But the risk of test than the water pressure test. When carrying out the test, the corresponding safety technical measures must be observed to prevent accidents during the test.
4, The density of the test: storage of liquid or gas welding containers, the welding seam is not dense defects, such as penetrating cracks, pores, slag, not penetration and loose tissue, can be used to find the density test. Denseness test methods are: kerosene test, water test, water test and so on.
5, Hydrostatic test: Each pipe should do hydrostatic test without leakage phenomenon, the test pressure is calculated by the test P = 2ST / D where the S-hydrostatic test test stress Mpa, hydrostatic test test stress by Corresponding to the standard steel yield minimum (235Mpa) 60% of the selected. D ≥ 508 Test pressure holding time of not less than 10 seconds 4, non-destructive testing of steel pipe welding seam, the steel head of the first seam and the circumferential seam should be Perform X-ray or ultrasonic inspection. Spiral welds in the direction of flammable ordinary fluids shall be subjected to 100% SX-ray or ultrasonic inspection and shall be subjected to X-ray or X-ray for helical welds of steel pipes for the transport of general fluids such as water, sewage, air and heating steam. Ultrasonic examination (20%).
