How much smoothness can the inner hole of the cold drawn seamless pipe reach?

The quality of the inner hole finish of the cold drawn seamless tubing will bring many troubles to customers, which will not only affect the customer's yield, but also affect the quality of the finished product. So what is the finish of the inner hole of the cold drawn seamless pipe? This is mainly based on the customer's product requirements. In the field of hydraulic steel pipes, the requirements for the inner hole finish of cold-drawn seamless pipes can reach Rz2.0mm/M.

Reasons affecting the inner hole finish of cold drawn seamless pipe

1) perforation
In many cases, due to immature perforation experience, uncontrollable perforation temperature, short perforation equipment, and uneven heating of round steel, the temperature deviation inside and outside the steel pipe is large, forming pits, pitting and warping skin, etc.As a result, the smoothness of the inner hole of the cold-drawn seamless pipe is not good. The perforated furnace should be lengthened so that the steel pipe is heated evenly.

2) Cold drawing die
Due to the defects of the cold drawing mold itself, the internal finish of the finished seamless pipe is not good. Professionally customized precision molds should be used. The higher the precision, the better the quality of the inner and outer surface finish of the finished product after cold drawing.

3) Pickling
Because of the strict environmental protection requirements in recent years, many manufacturers do not have the pickling process and professional experience, so they can only be processed outside.However, there is no data accumulation on the pickling time of the steel itself, so letting the processing factory process it at will, it will lead to the problem that the impurities inside the cold drawn seamless pipe cannot be completely cleaned, or the overacid forms pits, pitting and other problems. Different pickling methods and times should be used for different steel grades to ensure the smoothness of the inner hole.

4) Production process
Another important reason that affects the inner hole finish of the cold-drawn seamless pipe is the deformation of the seamless steel pipe during the cold-drawing process. The amount of deformation mainly depends on the number of passes of cold drawing. The smaller the amount of deformation, the higher the finish, but the cost will also increase. We should be based on quality and produce according to the actual needs of customers.

Article source: https://article-realm.com/article/Finance/29851-How-much-smoothness-can-the-inner-hole-of-the-cold-drawn-seamless-pipe-reach.html