Uneven wall thickness of seamless steel pipe

The thickness precision of seamless steel pipe is an important quality standard of seamless steel pipe, which has a very critical hazard to the performance indicators and production cost of seamless steel pipe. In the production process of seamless steel pipe will occur in the wall thickness disproportionate condition, which is how to cause it? The following and seamless steel pipe factory together with the analysis of.

　　A hot-rolled tube wall thickness is not proportional, the key or from hot-rolled once broken hole. The wall thickness of the buried pipe is not proportional, there are likely to be the following 3 levels of factors.

　　1, the tube material heating is not proportional, is generally said that the yin and yang face.

　　When the tube material is heated in the slant bottom furnace, the dialing material is not diligent, which will lead to half of the tube material “cooked”, half of the “raw”, when the hole is broken, the friction resistance is not the same, resulting in uneven wall thickness.

　　2, the top edge look and parts of the hazard.

　　Top edge application too much, part of the molten deposits out of the “table”, “table” of the height to width ratio is not proportional, equivalent to the top edge is not round, will endanger the wall thickness is not uniform; more serious, will continue to scratch the surface layer of the hair tube, resulting in internal ” heavy skin”. After the top edge part, will also endanger the wall thickness of the uniform.

　　3, small chain chatter.

　　Perforating machine assured that the rollers are not adjusted in time, can not be smoothly “hug” small chain, small chain fluttering, resulting in uneven wall thickness.

　　Second, cold-drawn steel pipe, cold-drawn seamless pipe thick-walled pipe uneven causes.

　　1) the front of the tube material cut tilt, bending too large, the tube material assured that the hole is skewed easily lead to uneven wall thickness of the top of the seamless steel pipe head.

　　2)The broadening index is very large when breaking the hole, the hot rolling strip speed ratio is too high, and the cold rolling is not stable.

　　3) Unstable steel throwing by the piercing machine easily leads to uneven wall thickness at the end of the hairpin.