Spiral welded steel pipe should undergo mechanical performance tests, flattening tests and expansion tests before leaving the factory, and must meet the requirements of the standards.
1. Judgment from the surface, that is, visual inspection. The appearance inspection of welded joints is a simple and widely used inspection method. It is an important part of finished product inspection, mainly to find defects and dimensional deviations on the weld surface. Inspection is generally carried out through naked eye observation with the help of tools such as standard templates, gauges and magnifying glasses. If there are defects on the surface of the weld, there may be defects inside the weld.
2. Inspection by physical methods: Physical inspection methods are methods that use some physical phenomena to measure or inspect. The inspection of internal defects in materials or workpieces generally uses non-destructive testing methods. Non-destructive testing includes ultrasonic testing, radiographic testing, penetrant testing, magnetic testing, etc.
3. Strength test of pressure vessels: In addition to sealing tests, pressure vessels must also undergo strength tests. There are two common types: water pressure test and air pressure test. They can both test the tightness of welds on vessels and pipes operating under pressure.
The air pressure test is more sensitive and faster than the water pressure test. At the same time, the products after the test do not need drainage treatment, which is especially suitable for products with difficult drainage. But the test is more dangerous than the hydrostatic test. When conducting tests, comply with corresponding safety technical measures to prevent accidents from occurring during the test.
4. Tightness test: For welded containers that store liquid or gas, the tightness test can be used to detect non-density defects in the weld seam, such as penetrating cracks, pores, slag inclusions, incomplete welding and loose tissue, etc. Tightness testing methods include: kerosene test, water-carrying test, water flushing test, etc.
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