What are the factors that cause steel ball quality problems

The broken, out-of-round or high wear of steel balls are almost all present together. 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 varieties 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 different chemical composition specifications. Qualified chemical die casting steel ball composition is the basic requirement of steel ball quality, and unqualified chemical composition will directly affect the raw material function.

2. Heat treatment technology

The heat treatment technology is inaccurate or the technology is accurate but not strictly implemented, the stress of the cast ball, the food machinery steel ball has not disappeared, the metallographic arrangement of the high chromium ball is unreasonable, and the remaining austenite is too high. The remaining austenite of the high chromium ball currently selected by the air quenching technology is usually 15%-30%. During the use process, the austenite is transformed into martensite, the volume expands, the internal stress increases, and the steel ball is impacting. Pieces of flaking occurred during the wear process, usually after 900-1000h of use in the mill, the situation is more severe.

• The molten iron contains high gas content, the charge is moist, and the moisture decomposes into hydrogen and oxygen at high temperatures, and there is no deoxidation before pouring. Perhaps the mold exhaust is not good, so pores are formed inside the cast ball, which reduces the strength of the cast ball.
• During the pouring process, the molten iron and the iron slag are not separated cleanly, forming slag holes in the casting ball, which also reduces the strength of the casting ball.
• In the production process, scrap steel is not strictly managed, and it is mixed with inferior waste materials, especially low melting point metal materials such as lead and zinc.