Quality inspection method of spiral pipe

The quality inspection method of spiral pipe (ssaw) is as follows:

1. Judging from the surface, that is, in visual inspection. Visual inspection of welded joints is a simple procedure with various inspection methods and is an important part of finished product inspection, mainly to find welding surface defects and dimensional deviations. Generally, it is observed by naked eyes and tested with tools such as standard models, gauges and magnifying glasses. If there is a flaw on the surface of the weld, there may be a flaw in the weld.

2. Physical inspection methods: Physical inspection methods are methods that use certain physical phenomena for inspection or testing. 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 by X-ray machines, software to automatically judge defects, locate defects, and measure defect sizes.

3. Strength test of the pressure vessel: In addition to the sealing test, the pressure vessel is also subjected to the strength test. Usually there are two kinds of hydraulic test and pneumatic test. They are able to 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 hydraulic testing. During the test, corresponding safety and technical measures must be observed in order to prevent accidents during the test.

4. Compaction test: For welded containers storing liquid or gas, there are no dense defects in the weld, such as penetrating cracks, pores, slag, impermeability and loose organization, etc., which can be used to find the compaction test. Densification test methods are: kerosene test, water test, water test, etc.

5. Hydrostatic pressure test Each steel pipe should be subjected to a hydrostatic test without leakage. The test pressure is according to the test pressure P = 2ST / D, where the hydrostatic test pressure of S is Mpa, and the hydrostatic test pressure is determined by the corresponding conditions. 60% of the output specified in the shape standard. Adjustment time: D < 508 test pressure is maintained for no less than 5 seconds; d ≥ 508 test pressure is maintained for no less than 10 seconds.

6. The non-destructive testing of structural steel pipe welds, steel head welds and ring joints should be carried out by X-ray or ultrasonic testing. For steel spiral welds conveyed by flammable common fluids, 100% X-ray or ultrasonic testing shall be performed. Spiral welds of steel pipes conveying general fluids such as water, sewage, air, heating steam, etc. 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.