How to improve the hardness of precision stainless steel pipes

Precision stainless steel pipes are steel pipes with extremely high requirements for size, R angle, roundness of pipe mouth, verticality, and roughness. For example, the length error needs to be controlled within 0.05mm. This kind of pipe is generally used in special industries or precision equipment, and sometimes there are requirements for hardness. So how to improve the hardness of precision stainless steel pipes?

First of all, let's understand the factors that affect the hardness of stainless steel precision pipes. There are two factors: annealing treatment and the carbon content of steel pipes. One of the factors is that the quality of the annealing treatment of stainless steel pipes is directly related to the hardness of the pipe. No matter what material the steel pipe is made of, the country has corresponding standards for its hardness. Another factor is carbon content. The main function of carbon is to improve the hardness of precision pipes, but carbon is also an impurity in stainless steel. The more carbon it contains, the harder it is, and the greater the chance of rusting the steel pipe.

Generally, if you want to improve the hardness of precision stainless steel pipes, without replacing the material, you can use the following two processes: annealing and drawing process methods to improve the hardness.

1. Annealing: Annealing is heating the metal to a specified temperature and then cooling it at a very slow and controlled rate. During cold working, the metal can harden. By pre-annealing the steel pipe, cold working can be performed without any risk of cracking, because annealing releases the mechanical stress generated during processing or grinding, making it easier to draw the stainless steel pipe later. When annealing, it is important not to exceed the annealing time, otherwise, the steel pipe will be too soft and the hardness may not meet the requirements after drawing.

2. Drawing: After annealing, the stainless steel pipe is drawn again. Drawing is divided into hot drawing and cold drawing. Cold drawing is to force stretching at room temperature with tensile stress exceeding the yield point strength of the original stainless steel product pipe, to produce plastic deformation to increase the yield point strength of the steel pipe, obtain the desired shape, and save materials.

During the drawing process, the thickness of the stainless steel welded steel pipe becomes thinner, while the hardness is also increased, and the cross-section along the entire length can be guaranteed to be completely consistent; secondly, the shape and size of the steel pipe are accurate, and the inner surface roughness can reach Ra≤0.01um.

The above is how to improve the hardness of precision stainless steel pipes. The factors that affect the hardness of steel pipes are annealing and carbon content. If you want to improve its hardness, you need to anneal it first to soften it, and then draw it, so that you can improve its hardness. In addition, if there is a requirement for the straightness of precision stainless steel pipes, they also need to be straightened.