Views: 1 Author: Site Editor Publish Time: 2021-06-10 Origin: Site
The scenes of steel ball broken, out of round or high wear are almost all present in quality accidents. As long as the stainless steel polished ball is broken and out of round, the wear must be high. The factors can be analyzed from the following aspects:
1. Unqualified chemical composition
Steel balls have different requirements for operating conditions, and there are many types of raw materials, including low chromium balls, medium chromium balls, high chromium balls and ultra-high chromium balls, as well as austenite ductile iron balls and martensitic ductile iron balls. Each kind of ball has a different chemical composition specification. Qualified chemical die casting steel ball composition is the most basic requirement for steel ball quality. Unqualified chemical composition will directly affect the function of the raw material.
2. Heat treatment technology
The heat treatment technology is not accurate or the technology is accurate but not strictly implemented. The stress of the cast ball is not eliminated. The metallographic arrangement of the high chromium ball is unreasonable, and the remaining austenite is too high. At present, the remaining austenite of the high chromium ball of the selected air quenching technology is usually 15%-30%. During the application process, the austenite is transformed into martensite, the volume expands, the internal stress increases, and the steel ball is impacting. Pieces of flaking occur during the wear process, usually after 900-1000h of use in the mill, this kind of scene is more severe.
3. The hot metal contains high gas content, the charge is wet, and the moisture decomposes into hydrogen and oxygen at high temperatures. There is no deoxidation before pouring. Perhaps the mold is not well vented, which causes pores in the cast ball and reduces the strength of the cast ball.
4. During the pouring process, the molten iron and the iron slag are not separated cleanly, forming the slag hole of the casting ball, which also reduces the strength of the casting ball.
5. In the production process, scrap steel is not strictly managed, and it is mixed with defective scraps, especially low-melting metal materials such as lead and zinc. The content of them is excessive, and they are simply broken.