More than 2% carbon content in iron carbon alloy casting. Carbon content of iron casting for industrial use generally 2% to 4%. Carbon in iron casting mostly exists in the form of graphite, and sometimes also exists in the form of cementite. In addition to carbon, the iron also contains 1% ~ 3% of silicon, and manganese, phosphorus, sulfur and other elements. Alloy iron casting also contains nickel, chromium, molybdenum, aluminum, copper, boron, vanadium and other elements. Carbon, silicon and iron affect the microstructure and properties of the key elements.
Cast iron can be divided into:
1. Gray iron casting. Higher carbon content (2.7% to 4.0%), carbon mainly exists in the form of flake graphite, the fracture was gray, short gray iron. Low melting point (1145 ~ 1250 ℃), a small amount of solidification shrinkage, compressive strength and hardness close to the carbon steel, and good shock absorption. Bed for the manufacture of machine tools, cylinders, boxes and other structural parts.
2. Iron casting. Carbon, low silicon content, the carbon mainly cementite forms exist, the fracture was silver. Solidification contraction of large, easy to produce shrinkage, cracks. High hardness, brittleness, can not bear impact load. More malleable iron casting used as blanks and the production of wear parts.
3. Malleable iron. After annealing white iron casting by the acquisition, distribution of graphite flake was, referred to ductile iron. The uniform microstructure and properties, wear resistance, good ductility and toughness. For the manufacture of complex shape, can withstand the strong dynamic load of parts.
4. Ductile iron. The molten iron casting was treated by globalization, spherical graphite precipitates, referred to as ductile iron. Than ordinary gray iron casting with high strength, good toughness and ductility. For the manufacture of internal combustion engines, auto parts and farm machinery.
5. Compacted graphite iron casting. The molten gray iron obtained by the creep of treatment, showed a worm-like graphite precipitation. Similar mechanical properties and ductile iron casting, cast performance range between gray iron and ductile iron. Used to manufacture car parts.
6. Alloy iron casting. Adding an appropriate amount of ordinary iron casting alloy elements (such as silicon, manganese, phosphorus, nickel, chromium, molybdenum, copper, aluminum, boron, vanadium, tin, etc.) received. Alloying element to iron change matrix, which has the corresponding heat, wear and corrosion resistance, low temperature or non-magnetic and other characteristics. For the manufacture of mining, chemical machinery and equipment, meters and other components.
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