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How to Detect the Quality of Spiral Steel Pipe

​Spiral steel pipe in the factory should do before the mechanical performance test and flattening test and flaring test, and to meet the requirements of the standard requirements. 

Spiral steel pipe quality testing methods are as follows:
1, From the surface to judge, that is, in the appearance of inspection. The appearance of the welded joint inspection is a simple procedure and a wide range of inspection methods, is an important part of the finished product inspection, mainly to find the weld surface defects and size of the deviation. Generally through the naked eye observation, with the standard model, gauge and magnifying glass and other tools for testing. If there is a defect on the surface of the weld, there may be a defect in the weld.

2, The physical method of inspection: the physical test method is the use of some physical phenomena for testing or testing methods. Materials or parts of the internal defects of the inspection, are generally used non-destructive testing methods. Non-destructive testing of ultrasonic testing, ray detection, penetration testing, magnetic detection and so on.

3, The strength of the pressure vessel test: pressure vessel, in addition to sealing test, but also for strength test. Commonly there are two kinds of hydraulic pressure test and air pressure test. They are able to test the weld densities of containers and pipes working under pressure. Pneumatic test is more sensitive and faster than hydraulic pressure test, while the product after the test without drainage, especially for difficult drainage products. But the risk of testing than the hydraulic test. During the test, the corresponding safety and technical measures must be observed to prevent accidents during the test.

4, Compactness test: the storage of liquid or gas welding containers, the weld is not dense defects, such as penetrating cracks, pores, slag, not penetration and loose tissue, etc., can be used to find the compact test. Densification test methods are: kerosene test, water test, water test and so on.

5, Hydrostatic test Each steel pipe should be hydrostatic test without leakage phenomenon, the test pressure by the test P = 2ST / D where the S-hydrostatic test test stress Mpa, hydrostatic test test stress by the corresponding The strip standard specifies 60% of the minimum yield. Regulator time: D <508 test pressure holding time of not less than 5 seconds; D ≥ 508 test pressure retention time of not less than 10 seconds.

6, Non-destructive testing of structural steel pipe welding seam, steel head weld and ring joints should be X-ray or ultrasonic testing. For helical welds of steel for combustible ordinary fluid delivery, a 100% SX-ray or ultrasonic test shall be carried out. The spiral welds of steel pipes for general fluid delivery such as water, sewage, air, heating steam shall be subjected to X-ray or Ultrasonic examination checks (20%).

According to the results of spiral steel pipe inspection, spiral steel pipe is usually divided into three categories: qualified goods, rework and waste. Qualified refers to the appearance of quality and quality of the quality of the relevant standards or delivery acceptance of technical conditions of the spiral steel pipe; Refurbished goods refers to the appearance of quality and internal quality is not fully meet the standards and acceptance of the bar, but to allow rework, rework after the standard and acceptance conditions Of the spiral steel pipe; scrap refers to the appearance of quality and quality of the internal failure, does not allow rework or rework after still fail to meet the standard and acceptance conditions of the spiral steel pipe.


Waste is divided into two kinds of waste and waste. Internal waste refers to the waste steel pipe found in the foundry or foundry workshop. The waste material found after the delivery of the spiral steel pipe is usually exposed to mechanical processing, heat treatment or use. The economic loss caused by it is far Much larger than the inside. In order to reduce the external waste, batch production of spiral steel pipe in the factory before the best sampling test heat treatment and rough processing, as far as possible in the spiral steel pipe plant found in the potential spiral carbon steel pipe defects in order to take the necessary early remedial instructions.


 

 Date:2017-05-27 09:22:37    From:www.hnssd.com

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