Steel pipes (especially seamless pipes, welded pipes) are widely used in high, medium and low pressure fluid transmission pipelines such as oil, natural gas, water, steam, gas, etc., as well as structural steel pipes and steel casing pipes for piling, bridges, and buildings. Good-quality steel pipes are convenient and beneficial to the people, but with the rapid development of steel pipes, some fake and inferior products will appear in the market one after another, so how to judge the quality of steel pipes?
First of all, we need to measure the diameter, wall thickness, length and appearance of the steel pipe to see if it meets the standard. Fake and inferior steel pipes often have pockmarks on the surface, and the material is poor. The end surface of the cut head is uneven, without metallic luster, the inner diameter fluctuates greatly, and it is easy to scratch and reduce the strength of the steel.
Secondly, do the water pressure test and whether the ultrasonic flaw detection is qualified. Hydrostatic testing is for steel pipes to withstand sufficient pressure during use to avoid potential safety hazards. On-line ultrasonic flaw detection is used for welding inspection of weld seams to prevent air holes and inclusions in steel pipes.
In addition, mechanical property experiments and chemical analysis are required. Such as the inspection of the surface quality of the steel pipe, the reinforcement of the weld, the roundness of the pipe, etc., must be carefully inspected to see if the result meets the standard. There are different standards for steel pipes in different fields. When unqualified steel pipes are detected, they must be repaired according to the standards. If they cannot be repaired, the steel pipes will be downgraded or scrapped. Strictly follow the requirements to ensure the quality of steel pipes.