site logo

Thick-walled stainless steel tube heat treatment deformation of three major factors

Thick-walled stainless steel tube heat treatment deformation of three major factors

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

Thick-walled stainless steel tube heat treatment deformation of three major factors

As we all know, the performance of thick-walled stainless steel tube after heat treatment will be better and more in line with the performance requirements of mechanical parts. However, in the process of thermal processing, the metal material will produce deformation and other problems. The appearance of metal material deformation has a fatal impact on the processing of mechanical parts. Here we understand together the three main factors of heat treatment deformation of thick-walled stainless steel pipe.

1. Quenching medium factors

Relevant practical research shows that in the implementation of the heat treatment process, the quenching medium selection and the effect of the heat treatment process is closely related to the occurrence of material deformation.

In the actual heat treatment, the choice of quenching medium quality affects the quenching effect of thick-walled stainless steel pipe, and its quenching stability is severely restricted. In addition, the mixing speed and method of the medium will also have a certain impact on the material. If the media mixing method is not reasonable, it will increase the possibility of material deformation.

2. Internal stress plastic deformation factor

In the heat treatment process of stainless steel products tube, uneven heating and cooling and uneven phase change time will produce internal stress, in certain plastic conditions with the internal stress plastic deformation will occur.

In the heating and cooling process, the inner and outer layers of the steel pipe are heated and cooled at different rates, resulting in different temperatures, leading to different degrees of thermal expansion and cold contraction. The resulting stress deformation is called thermal stress plastic deformation. During the heating and cooling process, the internal structure of the thick-walled stainless steel tube changes and changes at different times.

3. Volume deformation factor

Volume deformation in the heat treatment process of stainless steel welded pipe, the specific volume of the various phase structures are different, the volume and size changes in the phase transformation process is the specific volume deformation. Specific volume deformation is usually only related to the content of carbon and gold elements in austenite, the number of free phase carbides and ferrite, the difference in the specific volume of the organization before and after quenching, and the amount of residual austenite.

In general, volume deformation is caused by the change in specific volume during phase transformation. The mass volume of martensite is larger than the other constituent phases of the steel. When thick-walled stainless steel pipe is transformed from other constituent phases to martensite during heat treatment, the volume will inevitably increase. The mass volume of austenite is smaller than the mass volume of the other steel constituent phases. When it is transformed from other constituent phases to austenite during heat treatment, the volume will decrease.

Through the above introduction, we can learn that the factors of heat treatment deformation of thick-walled stainless steel pipe are mainly quenching medium and the speed of mixing of the medium; internal stress plastic deformation; volume deformation. The deformation of the heat treatment process has a certain impact on the efficiency, in order to ensure the accuracy of the thick-walled stainless steel tube, you need to take appropriate measures to control the deformation of the workpiece heat treatment process within the minimum range.