Cast iron is a black metal often used in construction and outdoor decoration. It has high hardness and brittleness, is not malleable, and is easier to melt than steel. In addition, the compression performance of this material is very good. Valves, cylinders, precision instruments, metal molds and other fields are also inseparable from this material.
Characteristics and Classification
1.Features: Contains high carbon and silicon elements, and a certain amount of manganese, phosphorus, sulfur and other impurity elements.
2.Ingredients: 2.5 4.0% C, 1.0 3.0% Si, 0.5 1.4% Mn, 0.01 0.5%, P 0.02 0.20% S.
3.Structure: C,Si content is high, most or even all of C exists in the form of free state graphite (G).
4.Disadvantages: poor strength, plasticity and toughness. And it can not be forged.
5.Advantages: Good castability, high anti-friction, machinability and low notch sensitivity, low price.
6.Classification: According to the fracture characteristics of cast iron classified into: gray iron, white iron, mottled iron.
Applications
1.Gray cast iron
Graphite morphology: Graphite is distributed in sheets
Composition: 2.5-3.6%C, 1.1-2.5%Si, 0.6-1.2%Mn, a small amount of P and S.
Structure: Graphite is flaky. The matrix comprises ferrite, ferrite + pearlite, pearlite, respectively using low, medium and high loads.
Disadvantages: The existence of flake graphite, large gaps and holes, low tensile strength, plasticity and toughness.
Advantages: good fluidity of molten iron; Solidification shrinkage; Notch sensitivity is small; Good machinability; It has anti-friction and anti-shock effect.
Heat treatment: can only change the matrix, can not change the shape and distribution of graphite, strengthening effect is not as good as steel and ductile iron.
Usage: Important castings with small dynamic load and high static strength requirements, such as machine tool bed and engine cylinder block.
2.Malleable cast iron.
Commonly known as mala steel, horse iron.
Graphite form: from white iron through graphitization annealing to decompose the cementation into a mass of flocculent graphite.
Classification: Black heart malleable iron, pearlite malleable iron, white heart malleable iron.
Composition: 2.4-2.8%C, 0.8-1.4%Si, 0.3-0.6%Mn.
Structure: The graphite is flocculent, and the matrix includes ferrite and pearlite.
Uses: Strength higher than gray cast iron, toughness close to cast steel, casting performance is better than cast steel, widely used in automobiles, tractors, agricultural machinery and railway parts, but also used in power line tools, pipeline connectors,
Of course, there are many other types of this material, which can produce complex forces and high-strength parts, as well as medium pressure valves for general purpose machinery. If you want to know more details, welcome to IBC Group consultation!
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