Improving the surface quality of stainless steel pipelines, including improving the surface morphology and structure, and reducing the number of layers, the common surface treatment methods at present are mechanical drawing, mechanical lapping, polishing and burning.
The mechanical drawing is to increase the surface roughness of the pipeline by using the plug bolt precision cold drawing, which can improve the surface structure of the pipelineline, but it will not improve the shape, energy level and the number of the intermediate layer of the stainless steel pipeline. This is one of the most basic surface treatment processes, and the roughness of the process is also the basis for other more complex surface treatment processes.
This way of treatment is most commonly used to improve the surface brightness of decorative stainless steel tubes. Although the Ra value may be very good, many cracks can be seen under the electron microscope, the actual surface area is enlarged, and there will be separate ferrite and martensite structure. The surface of a stainless steel tube is mixed with a lot of impurities, such as abrasive particles. In addition, because of the use of the polished paste, a lot of energy is stored in the sunken, resulting in the increase in the number of media.
Mechanical attrition is the way to improve the surface roughness of stainless steel pipelines by precision grinding. It can optimize the surface structure of pipelines, but it will not improve the shape, energy level and the number of interlayers.
Pickling or passivation
After pickling or passivation, the stainless steel pipelineline will not increase the surface roughness, but it can remove the residual particles on the pipeline surface and reduce the energy level, but it will not reduce the number of interlayers.
The high temperature heat treatment of stainless steel pipelines under hydrogenation or vacuum can not only eliminate the internal stress of pipelines, but also produce a passive film on the surface of stainless steel pipelines, thereby improving the morphology and structure, reducing the energy level, but it will not increase the surface roughness.
This method is coupled with a surface treatment process based on BA on the surface of the electrolytic polishing process is mild, so as to try to reduce the surface area, and thick passivation film, in order to improve the corrosion resistance performance, optimization of surface morphology of stainless steel tube and a lower energy level. Although the surface of stainless steel tube after such treatment is not bright, it also improves the surface quality to a large extent, and does not produce particles and reduce the composition of iron and iron oxide on the surface.
Through electrochemical polishing, the surface morphology and structure of the stainless steel pipeline can be greatly improved, and the actual area of the tube surface can be reduced to the maximum. The surface of the stainless steel tube is a fully protected chromium oxide film, and its energy is close to the normal level of the alloy, and the quantity of the medium will be reduced to the lowest.
Source: China Stainless Steel Pipelines Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)