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How much can the inner hole finish of cold drawn seamless tubing 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 tubing? This is mainly based on the product requirements of customers. In the field of hydraulic steel pipes, the requirements for the inner hole finish of cold drawn seamless tubing can reach Rz2.0mm/M.

What are the influences on the smoothness of the inner hole of the cold drawn seamless tubing?

1) Perforation

In many cases, due to the immature perforation experience, uncontrollable perforation temperature, short perforation equipment, and uneven heating of the round steel, the temperature deviation inside and outside the steel pipe is large, forming pits, pitting, etc. Okay. 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

Due to the strict environmental protection requirements in recent years, many manufacturers do not have the pickling process and have no professional experience, so they can only process them outside. The impurities inside the cold drawn seamless tubing cannot be completely cleaned, or the excessive acid forms pits, pitting and other problems. We should use different pickling methods and times 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 tubing 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.

Know more about this product price, catalogue, mill test certificate,  please inquiry to: sales@nan-steel.com

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