1 Judging from the surface, that is, in visual inspection. Visual inspection of welded joints is a simple procedure with a wide variety of inspection methods and is an important part of finished product inspection, mainly to find welding surface defects and dimensional deviations. Tests are generally carried out by visual inspection, with tools such as standard models, gauges, and magnifying glasses. If there is a defect in the surface of the weld, there may be a defect in the weld.
2 Physical inspection method: Physical inspection method is a method of using certain physical phenomena for inspection or inspection. The inspection of internal defects of materials or parts generally adopts non-destructive testing methods. X-ray flaw detection is the most commonly used method for non-destructive testing of spiral steel pipes
. The characteristics of this detection method are objective and direct, real-time imaging of X-ray machines, and software to automatically determine defects, locate defects, and measure defect sizes.
3 Strength test of pressure vessel: In addition to the sealing test, the pressure vessel is also tested for strength. Usually, there are two kinds of hydraulic tests and pneumatic tests. They can test the weld density of vessels and pipes working under pressure. Pneumatic testing is more sensitive and faster than hydraulic testing, and the tested product 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, corresponding safety and technical measures must be observed to prevent accidents.
4 Compaction degree test: Welded containers for storing liquid or gas, the welds have no dense defects, such as penetrating cracks, pores, slag, impermeability, loose organization, etc., can be used to find the compaction degree test. Densification test methods include kerosene test, water test, water test, etc.
5 Hydrostatic pressure test Each steel pipe should be hydrostatically tested without leakage, and the test pressure shall be according to the test pressure P = 2ST/D, in which the S hydrostatic test pressure is Mpa, and the hydrostatic test pressure is determined by the corresponding bar. 60% of the output specified by the shape standard. Adjustment time: D <508 test pressure holding time not less than 5 seconds; d ≥ 508 test pressure holding time not less than 10 seconds.
6 The non-destructive testing of structural steel pipe welds, steelhead welds, and annular joints shall be carried out by X-ray or ultrasonic testing. 100% X-ray or ultrasonic testing shall be performed for steel spiral welds for flammable common fluid transport. Spiral welds of steel pipes carrying general fluids such as water, sewage, air, heating steam, etc., should be inspected by X-ray or ultrasonic. The advantage of X-ray detection is that the imaging is objective, the professional requirements are not high, and the data can be stored and traced.