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1. Judging from the surface, that is, in visual inspection. The visual inspection of welded joints is a simple procedure with a wide variety of inspection methods. It is an important part of finished product inspection, mainly to find welding surface defects and dimensional deviations. Generally, the test is carried out by visual observation, using standard models, gauges, and magnifying glasses. If there are defects on the weld surface, there may be defects in the weld.
2. Physical inspection methods: Physical inspection methods are methods that use certain physical phenomena to inspect or inspect. The inspection of internal defects of materials or parts generally adopts non-destructive testing methods. X-ray inspection is one of the most commonly used methods of non-destructive testing for spiral steel pipes. The characteristics of this inspection method are objective and direct. X-ray machine real-time imaging, the software automatically judges defects, locates defects, and measures defect sizes.
3. Strength test of pressure vessel: In addition to the sealing test, the pressure vessel is also subjected to a strength test. There are usually two types of hydraulic tests and pneumatic tests. They can test the welding density of vessels and pipes that works under pressure. The pneumatic test is more sensitive and faster than the hydraulic test, and the product after the test does not need to be drained, especially for products that are difficult to drain. But the risk of testing is higher than that of hydraulic testing. During the test, the corresponding safety and technical measures must be observed to prevent accidents.
4. Compactness test: Welding containers for liquid or gas, the weld has no dense defects, such as penetrating cracks, pores, slag, impermeability and loose organization, etc., can be used to find the compaction test. Densification test methods include kerosene test, water test, water test, etc.
5. Hydrostatic pressure test Each steel pipe shall be subjected to a hydrostatic pressure test without leakage. The test pressure shall be P = 2ST/D, in which the hydrostatic pressure test pressure in S is Mpa, and the hydrostatic pressure test pressure shall be determined by the corresponding bar. 60% of the output specified by the shape standard. Adjustment time: D <508 tests pressure holding time not less than 5 seconds; d ≥ 508 test pressure holding time not less than 10 seconds.
6. Non-destructive testing of structural steel pipe welds, steelhead welds, and annular joints shall be X-ray or ultrasonic testing. For steel spiral welds conveyed by flammable ordinary fluids, 100% X-ray or ultrasonic testing should be carried out. Spiral welds of steel pipes that transport water, sewage, air, heating steam, and other general fluids should be inspected by X-ray or ultrasonic. The advantage of X-ray inspection is that the imaging is objective, the requirements for professionalism are not high, and the data can be stored and traced.