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Increase the hardness of precision stainless steel tube? Need these 2 processes

Increase the hardness of precision stainless steel tube? Need these 2 processes

Time:2022-04-13 Source:China Wuxi JiaNuo Special Steel Co.

Precision stainless steel tube is a kind of tube with very high requirements for size, R angle, orifice roundness, verticality, roughness, for example, the length error needs to be controlled within 0.05mm. And this tube is generally used in more special industries or precision equipment, sometimes there will be requirements for hardness. So how to improve the hardness of the precision stainless steel tube?

First, let’s understand the impact of stainless steel precision tube hardness, of which there are two factors: annealing treatment, the carbon content of the steel pipe. One of the factors is the stainless steel tube in the annealing treatment is directly related to the hardness of the tube, no matter what the material of the tube country has a corresponding standard for its hardness. Another factor is the carbon content, the main role of carbon in it is to enhance the hardness of the precision tube, but carbon in stainless steel is also an impurity, the more the content of the harder at the same time, the greater the chance of the tube rusting.

General precision stainless steel tube want to enhance the hardness, in the case of not replacing the material, generally through the following 2 processes: annealing, drawing process method to enhance the hardness.

1、Annealing treatment

Annealing is to heat the metal to a specified temperature, and then cooled at a very slow and controlled rate. During the cold working process, the metal is able to harden. By annealing the steel pipe in advance, cold working can be carried out without any risk of cracking, because annealing will release the mechanical stresses generated during processing or grinding, facilitating the drawing of stainless steel pipe later. In the annealing needs to be careful not to exceed the annealing time, otherwise the pipe will be too soft, and the hardness may not meet the requirements after drawing.


After annealing the stainless steel pipe, then drawing. Drawing is divided into hot and cold drawing, and cold drawing is at room temperature, to exceed the original stainless steel products tube yield point strength of tensile stress, forcible stretching, so that the plastic deformation to improve the yield point strength of the pipe, to obtain the desired shape and save material for the purpose.

In the process of drawing, the thickness of the stainless steel welded tube becomes thinner, while the hardness is also increased, and can ensure that the cross section along the entire length is completely consistent; secondly, the shape and size of the steel pipe is precise, and the internal surface roughness can reach Ra ≤ 0.01um.

The above is how to improve the hardness of the precision stainless steel tube content. The reasons affecting the hardness of the steel pipe are annealing and carbon content, and want to improve its hardness, it needs to be annealed first after softening, and then drawn, so that its hardness can be improved. In addition, if the straightness of the precision stainless steel tube requirements also need to be straightened.