First, acceptance principles for spiral steel pipes: The quality inspection and acceptance of spiral welded pipes shall be carried out by the supplier's technical quality supervision department. The supplier must ensure that the delivered spiral welded pipes meet the requirements of the corresponding product standards. The buyer has the right to inspect and accept according to the corresponding product standards. Spiral welded pipes should be submitted for acceptance in batches, and the batch rules should comply with the requirements of the corresponding product standards. The inspection items, sampling quantity, sampling location, and test methods of spiral steel pipes shall be according to the requirements of the corresponding product standards. With the consent of the buyer, spiral welded pipes can be sampled in batches according to the rolling root group.


Second, the classification of spiral steel pipe acceptance methods
1. Visual inspection: Visual inspection of spiral pipes is a simple and widely used test method. It is an important part of finished product inspection, defects, and deviations, mainly to find the size of the weld on the surface. Usually by the naked eye, with standard models, instruments, and detection tools such as magnifying glasses. If the weld surface is defective, the welding defect is likely to be internal.
2. Physical test method: The test method is to use the detected physical phenomenon or some physical test methods. In the inspection of defects in the internal spiral pipe of the material or work, non-destructive testing methods are generally used. Non-destructive testing ultrasonic testing, radiation testing, penetration testing, magnetic particle testing, etc.
3. Spiral steel pipe water pressure test standard: There should be no leakage to do each pipeline water pressure test, according to the test pressure test pressure MPa S-static water pressure test, test pressure test, to calculate P=2ST/D, where the water pressure test is by the minimum yield strip steel specified in the corresponding standard (Q235 is 235Mpa), 60% of people choose. Stabilization time: D<508 test pressure time is less than 5 seconds, D≥508 test pressure holding time is less than 10 seconds of steel pipe welding seam, steel bar head, and girth weld 4 non-destructive testing should be X-ray or ultrasonic inspection. For ordinary flammable fluids transported to the spiral seam steel pipe should be 100% SX-ray or ultrasonic testing, for water, sewage, air, steam, and other general heating fluid transport pipelines spiral welds should be X-ray or ultrasonic flaw detection inspection (20%).
4. Strength test of spiral steel pipe: Spiral steel pipe, in addition to the air tightness test, also for strength test. There are two common tests and spiral pipe water pressure test pressure. They can work on pressure test containers and pipeline welds. The hydrostatic pressure test is more sensitive than the test and speed, but it is particularly suitable for products with difficult drainage after testing products without wastewater treatment. However, the risk is greater than the water pressure test. During the test, the corresponding safety technical measures must be met to prevent accidents during the test 5, compactness test: liquid or gas shielded welding, which is not dense welding defects, such as penetration cracks, pores, slag inclusions in storage containers, incomplete penetration and loose tissue, etc., can be used to detect the density of the test. Intensive test methods are: kerosene test, ballast water test, and flushing test.


Third, the treatment of spiral welded pipe after the initial inspection
When a certain item does not meet the requirements of the product standard, the unqualified ones should be picked out, and from the same batch of spiral welded pipes, double the number of samples should be taken at will for re-inspection of the unqualified items. If the re-test results (including any index required by the project test) are unqualified, the batch of spiral welded pipes shall not be delivered. For spiral steel pipes with unqualified re-test results (including unqualified microstructure in the initial test results, and items that are not allowed to be re-tested), the supplier may submit them for acceptance one by one; or re-heat treat them (the number of re-heat treatments shall not exceed two times) and submit a new batch for acceptance. If there is no special provision in the product standard, the chemical composition of the spiral steel pipe shall be accepted according to the smelting composition.


Fourth, the final result of spiral steel pipe acceptance
According to the quality inspection results of spiral steel pipes, large-diameter spiral steel pipes are usually divided into three categories: qualified products, repaired products, and scrapped products. Qualified products refer to spiral steel pipes whose appearance quality and internal quality meet the relevant standards or delivery acceptance technical conditions; repaired products refer to spiral steel pipes whose appearance quality and internal quality do not fully meet the standards and acceptance bars, but are allowed to be repaired, and can meet the standards and acceptance conditions after repair; scrapped products refer to spiral steel pipes whose appearance quality and internal quality are unqualified, are not allowed to be repaired, or still fail to meet the standards and acceptance conditions after repair.