Straight seam steel pipe purchasing methods and processing methods

straight seam steel pipe purchasing method:
1. purchasing requires an understanding of the types of steel pipes
1) by type: straight seam steel pipe, seamless steel pipe, spiral steel pipe, etc.
2) sectional shape classification of straight seam steel pipes: square pipe, rectangular pipe, elliptical pipe, flat elliptical pipe, semi-circular pipe, etc.

2. need to pay attention to:
1) the wall thickness of the steel pipe is not enough to use the gate method. the mouth end of the steel pipe is shielded with a hammer and it looks thicker, but when measured with an instrument, the original shape will be revealed.
2) use a straight seam to act as a seamless steel pipe. the straight seam welds are relatively small and only have one longitudinal weld. use a machine to polish the entire steel pipe, commonly known as polishing. it will look like there is no gap to act as a seamless steel pipe.
3) nowadays, there is a more clever method which is seamless steel pipe. seamless steel pipe is also a thermally expanded steel pipe. after the expansion, there is a lead powder inside, and there are burn marks on the outside, but the weld seam cannot be seen. many larger steel pipes use this kind of steel pipe to act as seamless and sell it to make big profits.
4) the circumferential welded straight seam steel pipe uses polishing to replace the straight seam steel pipe.

the processing method of straight seam steel pipe:
①forged steel: a pressure processing method that uses the reciprocating impact of a forging hammer or the pressure of a press to change the blank into the shape and size we require.
②extrusion: it is a steel processing method in which metal is placed in a closed extrusion cylinder and pressure is applied on one end to extrude the metal from a specified die hole to obtain a finished product of the same shape and size. it is mostly used to produce non-ferrous metal materials. steel.
③rolling: a pressure processing method in which the steel metal blank is passed through the gap between a pair of rotating rollers (in various shapes). due to the compression of the rollers, the material section is reduced and the length is increased.
④ drawing steel: it is a processing method that draws the rolled metal blank (shaped, tube, product, etc.) through the die hole into a reduced cross-section and increased length. most of them are used for cold processing.