The spiral steel pipe in the factory should do well in mechanical performance test, flattening test and flaring test, and meet the requirements of the standard.


The quality inspection methods of spiral steel pipe are as follows:
1. Judging from the surface, that is, the appearance inspection. The appearance of welded joint inspection is a simple procedure and a wide range of inspection methods. It is an important part of finished product inspection, mainly to find out the surface defects and size deviation of weld. Usually through naked eye observation, with standard models, instruments and magnifiers and other tools for testing. If the surface of the weld is defective, the weld may be defective.


2. Physical test method: Physical test method is to use some physical phenomena to test or test. Non-destructive testing method is usually used to inspect the internal defects of materials or parts. Non-destructive testing such as ultrasonic testing, radiation testing, penetration testing, magnetic testing, etc.


3. Strength of pressure vessel test: pressure vessel, besides sealing test, is also used for strength test. There are usually two kinds of hydraulic and pneumatic tests. They can test the welding density of vessels and pipes working under pressure. Pneumatic test is more sensitive and faster than hydraulic test, and the product does not need drainage after test, especially for products that are difficult to drain. But the risk of testing is higher than that of hydraulic testing. During the test period, corresponding safety and technical measures must be observed to prevent accidents during the test period.


4. Compactness Tests: Containers for storing liquid or gas welding, non-compact defects of welds, such as penetrating cracks, blowhole, molten slag, impermeability and loose structure, can be used to find compact tests. Densification test methods include kerosene test, water test, water test and so on.


5. Hydraulic test should be carried out on each steel pipe without leakage. The test pressure is P = 2ST/D. The stress of S-hydraulic test is Mpa. The stress of hydraulic test corresponds to the minimum yield of 60% stipulated in the strip standard. Regulator time: D < 508 test pressure holding time is not less than 5 seconds; D < 508 test pressure holding time is not less than 10 seconds.


6. Non-destructive testing of steel pipe welds, steel head welds and annular joints should be carried out by X-ray or ultrasonic testing. For the spiral weld of flammable ordinary fluid conveying steel, 100% S X-ray or ultrasonic test should be carried out. Spiral welds of steel pipes for general fluid transportation, such as water, sewage, air and heated steam, should be examined by X-ray or ultrasonic (20%).


According to the inspection results of spiral steel tubes, spiral steel tubes are usually divided into three categories: qualified goods, rework and waste. Qualification refers to the appearance of relevant standards of quality and quality of threaded steel pipes or technical conditions for delivery and acceptance; renovated goods refer to the appearance quality and internal quality that do not fully meet the standards and acceptance standards, but allow rework, standards after rework and acceptance conditions of spiral steel pipes; scrap steel refers to the appearance of quality and quality of internal damage, and does not allow rework or rework still does not conform to spiral steel pipes. Standards and acceptance conditions.


Waste is divided into waste and waste. Internal waste refers to waste steel pipes in foundries or foundry workshops. Waste found after conveying spiral steel tubes is usually machined, heat treated or used. Its economic losses are far greater than internal losses. In order to reduce external waste, it is better to sample, test, heat treatment and rough processing for mass production of spiral steel pipe before leaving the factory. Potential defects of spiral steel pipe can be found as far as possible in the spiral steel pipe factory so as to take necessary early remedial instructions.