Cold drawn seamless tube inner hole smoothness

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

What are the effects of the smoothness of the inner hole of the cold drawn seamless tube?

1) perforation

In many cases, due to immature piercing experience, uncontrollable piercing temperature, short piercing equipment, and uneven heating of the round steel, the temperature deviation between the inside and outside of the steel pipe is large, forming pits and pits. The piercing furnace should be lengthened so that the steel pipe is heated evenly.

2) cold drawing die

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

3) pickling

Due to strict environmental protection requirements in recent years, many manufacturers have no pickling process and no professional experience, so they can only process outside. The impurities inside the cold-drawn seamless pipe cannot be completely cleaned, or there are problems such as pitting and pitting caused by too much acid. Different steel types should adopt different pickling methods and times to ensure the smoothness of the inner hole.

4) Production process

Another important reason that affects the smoothness of the inner hole of the cold drawn seamless steel 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.

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