Cast iron for automobile parts
Properties and characteristics of cast iron: Compared with steel, its strength is low, especially toughness and plasticity is poor, but the casting performance is good, wear resistance, cutting performance is good.
With the progress of technology, some traditional automobile parts made of cast iron have been replaced by light metals gradually.
Cast iron is divided into white cast iron, grey cast iron, malleable iron, ductile iron and alloy cast iron.
White cast iron: White cast iron fracture is white, hard and brittle performance, it is difficult to cut, mainly used for steelmaking.
Gray cast iron: Gray cast iron fracture is gray, because the production process is simpler than the barrel, low cost, low melting point, small shrinkage, good casting performance, in the automotive parts more gray cast iron grades with "HT" and digital composition. Among them, the number represents the lowest tensile strength. For example, HT100 is the gray iron with the lowest tensile strength of 100N/mm2.
Malleable cast iron: commonly known as horse iron; it has high strength and toughness; can be used to make parts withstanding impact and vibration; can not be forged
Ductile iron: commonly known as ductile iron; ductile iron has both physical and chemical properties of cast iron and steel, mechanical properties and technological properties, but also like steel can be heat treated. After alloying and various heat treatments, it can be used to replace cast steel and forged steel to manufacture some parts with complicated force and high performance requirements, such as crankshafts, camshafts, gears and connecting rods of high-power diesel engines instead of 45 steel and 350CrMo steel; the grade of nodular cast iron consists of QT and two sets of figures. First groups of numbers represent the lowest tensile strength, and the second group represents the lowest elongation. For example, QT400-18 shows ductile iron with a minimum tensile strength of 400N/mm2 and a minimum elongation of 18%.
Alloy cast iron: Including gray iron or ductile iron in particular to add a certain amount of alloy elements, to obtain special properties of cast iron called alloy cast iron.
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