Key points in the process of High Chromium Steel Ball Casting
Generally speaking, the end customers of wear-resistant materials companies mainly include mining, cement, construction and power plants. The performance of the wear-resistant steel ball is related to the cost and benefit of the end-user enterprise. At present, with the technical improvement of wear-resistant casting companies, the replacement of low-efficiency steel balls with high-performance and high-grinding efficiency is becoming more and more obvious.
High-chromium steel balls are made by adding trace elements such as gold, chromium, manganese to the original chemical composition, using advanced technology such as anhydrous resin sand molding and oil quenching heat treatment to produce good toughness High performance wear resistant steel ball with high wear resistance. This kind of product performance is good, can prolong wear-resistant steel ball use cycle, reduce wear-resistant material enterprise production cost, labor cost.
Here are a few key points of the high chromium steel ball casting process:
- The casting temperature of high chromium steel ball casting should be lower, which is beneficial to refine dendrites and eutectic structure and can avoid shrinkage and surface sand burn-in caused by too high temperature. Pouring temperature is generally higher than its liquid phase line (1290 something 1350 degrees) about 55 degrees, the light piece is generally controlled at 1380 –1420 degrees, wall thickness l00ram above the heavy parts control at 1350–1400 degrees.
- The shrinkage of high chromium cast iron is similar to that of cast steel. The linear shrinkage of high chromium cast iron can be calculated by 1.8 %, 2 %. In sand mold making, the riser size can be calculated according to carbon steel rules, and the gating system can be calculated according to gray iron, but the sectional area should be increased by 200 %. The choice of gating and riser should pay attention to two aspects: one is to ensure the quality of casting working belt (using position), the other is to improve the yield of casting.
- High Chromium cast iron has poor casting properties, low thermal conductivity, poor plasticity, large shrinkage, and the large tendency of hot cracking and cold cracking. In the casting process of high chromium steel, the characteristics of CAST STEEL AND CAST IRON SHOULD BE CONSIDERED Full attention must be paid to the feeding of the castings in the same principle as for steel castings (risers and chills are used, and the sequential solidification principle is followed). Because of the high chromium content in the high chromium Alloy Steel Ball, easy in the iron surface conjunctive, so it seems that the fluidity of iron is poor, but actually, the fluidity is good.
- Because the risers of high-chromium castings are difficult to be cut off, so side risers or easy-cut risers should be adopted in the form of risers.
- When casting high chromium steel ball, the mold should be high strength and good air permeability sand, such as sodium silicate. The coating should be mixed with alcohol and high aluminum powder or magnesium powder. In addition, in order to obtain fine grain structure and good surface quality, metal mold casting is also widely used in the case of less complicated casting shape.