Quality Inspection Of SSAW Steel Pipe Before Delivery

SSAW steel pipe should be subjected to quality inspection, and must meet the requirements of the standard before leaving the factory. The quality inspection method of spiral steel pipe is as follows.

1. Appearance Inspection

The appearance inspection of welded joints is a simple and widely used inspection method. It is an important part of finished product inspection, mainly to find defects and dimensional deviations on the weld surface. It is generally inspected by naked eyes, with the help of tools such as standard templates, gauges and magnifying glasses. If there are defects on the surface of the weld, there may be defects inside the weld.

2. Physical Inspection

Physical inspection methods are methods that use some physical phenomena to measure or inspect. The inspection of internal defects of materials or workpieces generally adopts non-destructive testing methods. Non-destructive testing includes ultrasonic testing, radiographic testing, penetrating testing, magnetic testing, etc.

3. Strength Inspection of Pressure Vessel

In addition to the tightness test, the pressure vessel must be subjected to a strength test. There are two common types: hydraulic test and pneumatic test. They can test the tightness of welds of vessels and pipes that work under pressure. The air pressure test is more sensitive and faster than the water pressure test, and the product after the test does not need to be drained, which is especially suitable for products with difficult drainage. But the risk of the test is greater than that of the hydraulic test. When conducting the test, the corresponding safety technical measures must be followed to prevent accidents during the test.

4. Denseness Inspection

For welded containers that store liquids or gases, the imperfections of the welds, such as penetrating cracks, pores, slag inclusions, incomplete penetration and loose structure, can be found by the compactness test. The tightness test methods include: kerosene test, water-carrying test, water wash test, etc.

5. Hydrostatic Test

Each steel pipe should be subjected to hydrostatic pressure test without leakage. The test pressure is calculated by pressing P=2ST/D where S—the test stress of hydrostatic test Mpa, and the test stress of hydrostatic test shall be in accordance with the corresponding steel strip standard. 60% of the minimum yield (Q235 is 235Mpa) is selected. Stabilization time: D<508 test pressure holding time is no less than 5 seconds; D≥508 test pressure holding time is no less than 10 seconds

6. Non-Destructive Testing

X-ray or ultrasonic inspection shall be carried out for repair welding seams of steel pipes, butt weld seams of steel strips and circumferential seams. 100% SX-ray or ultrasonic inspection should be carried out for the steel-direction spiral welds used for the transportation of flammable ordinary fluids, and the spiral welds of the steel pipes used for the transportation of water, sewage, air, heating steam and other ordinary fluids should be X-ray or Ultrasonic inspection spot check (20%).

According to the quality inspection results of SSAW steel pipes, spiral steel pipes are usually divided into: qualified products, repaired products and scrap products. Only those qualified products whose appearance and internal quality meet the relevant standards or technical requirements for delivery and acceptance.

Union Steel can offer high quality SSAW steel pipes, if you want to get more details, contact us: sales@union-steels.com

Relative Article:

Welding Quality Standard of Spiral Steel Pipe