1. Purchasing needs to understand the types of steel pipes:
A. Divided by type: straight seam steel pipe, seamless steel pipe, spiral steel pipe, etc.
B. Classification of cross-section shapes of straight seam steel pipes: square pipe, rectangular pipe, elliptical pipe, flat ellipse pipe, semicircular pipe, etc.
2. Points to note:
In the early days of the steel pipe industry, there were more deceptive tricks, but now people are more proficient in this industry, so those methods can be recognized by our naked eyes.
A. The wall thickness of the steel pipe is not enough. Using the gate means, the mouth end of the steel pipe looks thicker with a hammer shield, but the original shape will be revealed by measuring with an instrument.
B. Use straight seams as seamless steel pipes. The number of straight seam welds is less than one longitudinal weld. The whole steel pipe is polished with a machine, commonly known as polishing, which acts as seamless as if there is no gap.
C. Now there is still a more clever method is a seamless steel pipe, which is also a heat-expanded steel pipe. After the expansion, there is a lead powder inside, and there are burn marks on the outside. The welds are also invisible. Many relatively large steel pipes are sold seamlessly using this type of steel pipe to seek large profits.
D. Circumferential welded seam steel pipes use polishing to represent seamless steel pipes and straight seam steel pipes.
Post time: Jun-25-2021