Quality Inspection of SSAW Steel Pipe

SSAW steel pipe shall be tested for mechanical properties, flattening and flaring before they leave the factory, and shall meet the requirements stipulated in the standard. The quality inspection methods of SSAW steel pipes are as follows: 

1. Visual inspection. The appearance inspection of welded joints is a simple and widely used inspection method, which is an important content of finished product inspection, mainly used to find defects and dimensional deviations on the surface of the weld. Generally, it is inspected by eyes and with the help of tools such as standard templates, gauges and magnifying glasses. If there is a defect on the surface of the weld, there may be a defect inside the weld. 

2. Physical Inspection methods: The physical inspection method is measuring or inspecting with some physical phenomena. The inspection of internal defects of materials or workpieces is generally performed by non-destructive testing. Non-destructive testing includes ultrasonic testing, radiographic testing, penetration testing, magnetic testing, etc. 

3. Strength inspection of pressure vessels: In addition to the tightness test, the pressure vessel also undergo a strength test. They are water pressure test and air pressure test. They can check the tightness of the welds of containers and pipes that work under pressure. The air pressure test is more sensitive and faster than the water pressure test. At the same time, the product after the test does not need to be drained. It is especially suitable for products with difficult drainage. But the risk of the test is greater than the hydrostatic test. When conducting the test, the corresponding safety technical measures must be observed to prevent accidents during the test. 

4. Tightness test: Welding containers storing liquids or gases, the non-density defects of the welds, such as penetrating cracks, pores, slag inclusions, under-welded and loose tissues, etc., can be found by the compactness test. Denseness testing methods include: kerosene test, water load test, water flush test, etc. 

5. Hydrostatic test: Each steel pipe should be do hydrostatically test without leakage. The test pressure is calculated by pressing the test P=2ST/D, the test stress Mpa of the hydrostatic test, the test stress of the hydrostatic test is according to the corresponding The steel strip standard specifies 60% of the minimum yield value (Q235 is 235Mpa). Pressure stabilization time: D<508 test pressure retention time is not less than seconds; D≥508 test pressure retention time is not less than 10 seconds 4 Non-destructive testing steel pipe repair welding seam, steel tape butt welding seam and girth seam should be carried out X-ray or ultrasonic inspection. The spiral welds of steel for flammable general fluid transportation should be 100% SX-ray or ultrasonic inspection, and the spiral welds of steel pipes for general fluid transportation of water, sewage, air, heating steam, etc. should be X-ray or Ultrasonic inspection spot check (20%).