First, the procurement needs to understand the type of steel pipe.
1. According to the type: straight seam steel pipe, seamless steel pipe , spiral steel pipe, etc.
2. cross-sectional shape classification of straight seam steel pipe classification : square tube, rectangular tube, elliptical tube, flat oval tube, semi-circular tube, etc.
Second, the points to pay attention to:
In the early days of the steel pipe industry, there were a lot of tricks, but now people are more proficient in this industry, so those tools can be identified by our naked eyes.
1. The wall thickness of the steel pipe is not enough. The mouth of the steel pipe is thicker with the hammer shield, but it will be exposed by the instrument.
2. Straight seams are used as seamless steel tubes. Straight seam welds are less than one longitudinal weld seam. The whole steel tube is polished by machine, commonly known as polishing, and looks like seamless with no gaps.
3. There is still a more sophisticated means to seamlessly weld steel pipes, and seamless steel pipes are also hot-expanded steel pipes. After the expansion, there is lead powder inside, and there are also traces of burning on the outside. The welds are also invisible. Many large steel pipes use this steel pipe to sell seamlessly and seek large profits.
4. the ring weld straight seam steel pipe uses polishing to represent seamless steel pipe, straight seam steel pipe