Attention requirement and die design for cold drawing tube pretreatment

- Apr 13, 2018-

In the cold drawing pipe, when the steel pipe is not treated before it is untreated, the friction coefficient between the surface of the steel tube and the mold is too large when it is cold drawn, so the drawing can not be carried out. Only through the pretreatment process, the steel pipe is rusting first, and the inner and outer surfaces are formed by the treatment of phosphating and saponification. A compact metal soap film is used to reduce the friction between the steel tube and the die, so as to ensure the smooth operation of the drawing.


The early treatment of the cold drawing tube can effectively reduce the loss rate of the die, so that the rate of finished product and work efficiency can be improved to a certain extent, and the finished surface of the finished product is smooth and uniform, and the anti rust effect is good.

Attention should be paid to the following points in the pretreatment of cold drawn tubes

1., acid cleaning and rust removal must be thorough. Once it is found that the rust is not removed, it needs to be pickled again.

2. in production, the concentration of phosphating liquid and saponified liquid should be tested regularly to ensure the production index of phosphating liquid and saponified liquid. It is found that timely deployment should be carried out when the index is not reached.

3., we must strictly control the temperature and operation time of the treatment fluid.

Design of die for cold drawing tube

The cold drawing tube is made of a certain shape and size mould under the action of force, and the dimension precision and surface quality of the die directly affect the size accuracy and quality of the finished product.

1. the determination of the diameter of the inner and outer die should take into account the resilience of the finished product, the low hardness and the small deformation, and its resilience is small, the hardness is high, and the deformation amount is large, and its springback is large.

2., the surface of the mold should have a lower roughness requirement, and the general value is lower than the finished product by one to two level.

3. the material is high strength and wear-resistant material.