In China metallurgical mines (such as iron ore, copper ore, lead-zinc ore, gold ore, etc.), wet ball mill liners are mainly made of ordinary high manganese steel, while some enterprises use liners made from high chromium-high manganese steel or Ultra High Manganese Steel Liners. These wet ball mill liners face harsh operating conditions during use, requiring them to resist corrosion, impact, and wear. High manganese steel liners are well known for their excellent impact toughness and impact resistance but perform poorly in terms of wear resistance and corrosion resistance.
To adapt to the extreme operating conditions in the mining industry, Duma Machinery has developed an Ultra High Manganese Steel Liner with excellent performance, which has been applied to 1.53.0 meter and 2.73.6 meter ball mills. This has successfully improved the grinding efficiency of iron ore and increased the service life of the ball mill liners by more than twice that of ordinary high manganese steel liners.
Regarding the influence of carbon content on the yield strength and elongation of manganese steel castings, studies show that as the carbon content increases, the wear resistance of high manganese steel castings also improves. However, if the carbon content exceeds 1.4%, carbides may form at the grain boundaries, weakening the strength and ductility of the steel, which is why steel with a carbon content above this level is rarely used.
Moreover, the effect of carbon content on the wear resistance of manganese steel castings is also very noticeable. Low carbon content (at least 0.7% C) can effectively reduce the precipitation of carbides in heavy castings or welded parts, while also providing low-carbon material for welding filler metals. On the other hand, the role of manganese as an austenite stabilizer cannot be ignored. Excessive manganese content will stabilize the austenite phase in steel at room temperature. Austenite has an FCC crystal structure, which causes the yield strength to decrease when the manganese content is too high.
The addition of chromium can improve the hardness and corrosion resistance of steel. As a carbide-forming agent, excessive chromium will lead to the precipitation of carbides at the grain boundaries. Research shows that to reduce the volume fraction of carbides and maintain good impact toughness, the chromium content should be limited to 0.1%. In addition, these carbides can be removed by solution treatment in the temperature range of 1050°C to 1100°C. If carbides are present in the quenched structure, they should be ensured to appear as harmless particles or nodules inside the austenite grains, rather than as continuous layers at the grain boundaries. After such treatment, the yield strength will increase, but the impact energy will slightly decrease.
