Steel castings are used for manufacturing machinery accessories with higher requirements on intensity, plasticity and toughness. Output of steel casting products is just next to that of iron castings, accounting for 15% of the overall output of castings.
Based on the chemical components of raw materials, steels used for casting process can be classified into carbon steels and alloy steels. Carbon steels are the most widely used one so that output of carbon steel castings covers more than 80% of total steel castings.
(1) In general, ZG15 low-carbon steel is only used for manufacturing motor parts or carburized parts for its high melting point and poor castability.
(2) ZG25～ZG45 medium carbon steels have superb comprehensive performance which is superior to other kinds of cast steels. With strong intensity, excellent plasticity and toughness, it is suitable for producing complex accessories such as train wheels, frames, anvils, rollers, high pressure valves, etc. This is the mainly used kind of cast steels.
(3) ZG55 high-carbon steel have low melting point. Its castability is better than medium carbon steels while the plasticity and toughness are poorer. Therefore, it is only used for manufacturing a few kinds of wear-resistant parts.
According to content of alloy elements, alloy steel casting fall broadly into two categories: low alloy steels and high alloy steels.
(1)Frequently used low alloy cast steels in China include manganese, ferromanganese silicon and chrome, such as ZG40Mn, ZG30MnSi1, ZG30Cr1MnSi1. They are mainly applied to the manufacture of gears, working cylinders in hydraulic presses and turbine rotors. ZG40Cr1 steel is often used to produce important loaded parts like gears and axles with high strength.
(2)High alloy cast steels are featured with wear-resistance, heat-resistance and anti-corrosion. ZGMn13 high manganese steel is wear-resisting. It is mainly used for producing accessories that work under dry friction conditions, like front walls and teeth in grab buckets of excavator or tracks of tractors and tanks.
ZG1Cr18Ni9 chromium nickel stainless steel, ZG1Cr13 and ZGCr28 chromium stainless steels can effectively resist corrosion from nitric acid. They are mainly used for producing equipment parts in chemical engineering, petroleum, chemical fiber and food industries.
