Surface Machining Defects of Seamless Steel Tubes and Their Prevention
Date:2022-03-22 keywords: seamless steel tube
Surface machining defects of seamless steel tubes and their prevention:
⒈ The surface processing of seamless steel tubes mainly includes: surface shot peening, overall surface grinding and mechanical processing.
⒉ Purpose: To further improve the surface quality and dimensional accuracy of seamless steel pipes.
⒊ The tools for overall grinding of the outer surface of the seamless steel tube mainly include: abrasive belt, grinding wheel and grinding machine. Some small defects on the surface of the steel pipe such as small cracks, hair lines, pits, scratches, etc.
①Use the abrasive belt or grinding wheel to grind the surface of the steel pipe as a whole, and the possible quality defects mainly include: black skin on the surface of the steel pipe, excessive wall thickness, plane (polygon), pits, burns and wear marks.
②The black skin on the surface of the steel pipe is because the grinding amount is too small or there are pits on the surface of the steel pipe. Increasing the grinding amount can eliminate the black skin on the surface of the steel pipe.
③The over-tolerance of the wall thickness of the steel pipe is caused by the large negative deviation of the wall thickness of the steel pipe itself or the large amount of grinding.
④ Burns on the surface of the steel pipe are mainly due to the excessive contact stress between the grinding wheel and the surface of the steel pipe, the grinding amount of the steel pipe for one time grinding is too large, and the grinding wheel used is too rough.
⑤Reduce the grinding amount of the steel pipe at one time, use the coarse grinding wheel for the rough grinding of the steel pipe, and use the fine grinding wheel for the fine grinding, which can not only prevent the surface burn of the steel pipe, but also reduce the wear marks on the surface of the steel pipe.
⒋ Shot peening on the surface of seamless steel tubes
①Shot peening on the surface of steel pipe is to spray iron shot or quartz sand shot of a certain size on the surface of the steel pipe at a high speed to knock off the oxide skin on the surface to improve the surface finish of the steel pipe.
② The size and hardness of the sand shot and the injection speed are important factors affecting the quality of the shot peening on the surface of the steel pipe.
⒌ Surface machining of seamless steel tubes
①Some steel tubes with higher inner and outer surface quality requirements need to be machined.
②The dimensional accuracy, surface quality and curvature of machined pipes are unmatched by hot-rolled pipes.
In short, the finishing process is an indispensable and very important process to ensure the quality of the steel pipe. Strengthening the role of the finishing process will undoubtedly help to further improve the quality of the seamless steel pipe.
