Gear sleeve large steel casting is widely used in forging and press machine.Steel casting is the metal part obtained by casting.That is the molten liquid metal is poured into the mold by casting and after cooling,get the casting shape,size and performance by shakeout and cleaning.For the machine castings with higher strength, plasticity and toughness requirements,it need steel castings. Steel castings production rank only second to iron castings and account for about 15% of total castings.
According to chemical composition, steel casting can be divided into two types: carbon steel casting and alloy steel casting.Carbon steel casting is the most widely used among them and account for more than 80% of total steel castings .
1. carbon steel casting
Low carbon steel ZG15 with high melting point and poor casting performance and is only for motor steel casting or steel carburized parts;medium carbon steel ZG25 ~ ZG45 with higher performance(high strength,good plasticity and roughness) than iron casting, so it is suitable for manufacturing the castings with complex shape, such as train wheels casting, hammer frame casting, anvil casting, pressure roller casting and high pressure valves casting, is the most widely used in carbon steel casting; high carbon steel ZG55 with low melting point, the casting performance is better than medium carbon steel, but the plasticity and toughness is poor, so it is only used to manufacture few wear-resistant casting.
2. alloy cast steel casting
According to the total amount of alloy elements, alloy cast steel casting can be divided into low alloy steel and high alloy steel.
1) low alloy cast steel casting,it is mainly used in manganese, manganese silicon and chromium. Such as ZG40Mn, ZG30MnSi1, ZG30Cr1MnSi1 and so on.It is used to manufacture the gears casting, hydraulic presses casting, turbine rotor casting, etc.and ZG40Cr1 is often used to make high strength gear wheel casting and shaft casting ,etc.
2) high alloy cast steel casting has special properties such as wear resistance, heat resistance or corrosion resistance. Such as high manganese steel casting ZGMn13 is a wear-resistant steel casting and mainly used to manufacture the excavators steel casting and caterpillar steel casting for tractor and tank
Casting process feature for steel casting: steel casting’s mechanical properties is higher than iron casting, but its casting performance is worse than iron casting due to the melting point of steel casting is higher and the liquid steel is easy to oxidize with poor fluidity of molten steel and large shrinkage , the shrinkage ratio is 10 ~ 14%, and the line shrinkage is 1.8 ~ 2.5%. In order to prevent the steel castings from defects such as insufficient casting, cold separation, shrinkage hole and shrinkage porosity, crack and sand penetration. it is necessary to adopt more complicated technological measures than iron casting.