The spiral pipe factory should carry out mechanical performance test and flattening test, and carry out expansion test, and meet the standard requirements. The quality inspection methods of straight seam steel plate are as follows:
1. On the surface, it is visual inspection. Visual inspection of welded joints is a simple process, but widely used testing methods are an important part of product testing. The main defects and deviations are found on the welded surface. Usually with the naked eye, with standard models, instruments and test tools such as magnifiers. If there is a defect on the surface of the weld, there may be an internal defect in the weld.


2. Physical testing methods: Physical testing methods use some physical phenomena or testing methods. Or in the inspection of workpiece material defects, NDT method is generally used. NDT ultrasonic flaw detection, radiation detection, penetration test, magnetic test, etc.
 
3. Strength test of pressure vessel: In addition to sealing test, strength test should be carried out for pressure vessel. There are two kinds of hydraulic and pneumatic tests. They can be tested under tight welding conditions for pressure vessels and pipes. The hydrostatic pressure test is more sensitive than the test speed. At the same time, when the test product is not treated with wastewater, the drainage problem of the product is particularly applicable. But the risk is greater than the test stress test. During testing, proper safety measures must be observed to prevent accidents during testing.
 
4. Compact test: The welding of liquid or gas storage containers, which is not compact welding defects, such as penetrating cracks, pore, slag, incompletely permeable and loose structure, can be used to find density test. Compact test methods include kerosene test, carrying water test, water test, etc.


5. Hydraulic test: Pressure calculation P = 2ST / D should be carried out under leak-free test pressure for each pipeline, in which S-hydraulic test stress test Mpa is 60% of the minimum yield strength (Q235) specified in hydraulic test stress test according to corresponding steel standards.