Mechanical Properties Of Cast Iron

- Aug 24, 2017 -

Cast iron carbon content is relatively high, casting performance is better, you can use casting method to process the shape of the relatively complex parts. Cast iron is divided into gray cast iron, ductile iron and so on.

Cast iron is not pure iron, it is a Fe, C, Iron Casting Si as the main component and in the crystallization process with eutectic transition of the multi-iron-based alloy. Chemical composition is generally: C2.5% -4.0%, Si1.0% a 3,0%, P0.4% ~ 1.5%, S0.02% -02%. Iron Casting In order to improve the mechanical properties of cast iron, usually in the cast iron composition to add a small amount of Cr, Ni, Co, Mi, Iron Casting and other alloying elements made of cast iron.

First, the characteristics of cast iron

1. Composition and organizational characteristics

Compared with carbon steel, the chemical composition has higher C, Si content (C2.5% ~ 4,0%, Si1.0%-3.0%), but also contains high impurity element Mn, P, S, in the special performance of the alloy cast iron, also contains some alloying elements. All of these elements of the existence and content, Iron Casting will have a direct impact on the organization and performance of cast iron. Since the carbon in the cast iron is mainly in the form of graphite (G), so the organization of cast iron is composed of metal matrix and graphite. Cast iron metal matrix pearlite, Iron Casting ferrite and pearlite plus ferrite three categories, they are equivalent to the steel structure. Therefore, Iron Casting the organization of cast iron characteristics, can be seen in the steel on the base of the distribution of different shapes of graphite.

2. Performance characteristics of cast iron

Cast iron tensile strength, plasticity and toughness than carbon steel low. Although the mechanical properties of cast iron than steel, but because of the presence of graphite, but given many of the cast iron for the performance of steel. Such as good wear resistance, high vibration resistance, Iron Casting low gap sensitivity and excellent cutting performance. In addition, cast iron has a high carbon content and its composition is close to the eutectic composition. Therefore, the melting point of the cast iron is about 1200 ° C, Iron Casting the molten iron is fluidly flowable, and the casting shrinkage is small due to the volume expansion of the graphite crystal Yu steel, Iron Casting which is usually made by casting casting use, it is called cast iron.

Second, the classification of cast iron

There are many ways to classify cast iron. According to the form of carbon can be divided into three kinds:

1. White cast iron (referred to as white iron)

White carbon in the cast iron is mainly in the form of cementite (Cm), Iron Casting the fracture is white and bright. Its performance is hard and brittle, and cutting is difficult. Except for a small number used to make high hardness, wear, no need to process the parts or surface requirements of high hardness, wear-resistant chilled castings (such as crusher plate, roll, train wheel, etc.), Iron Casting but also as a steelmaking raw materials and Malleable cast iron.

2. Gray cast iron (referred to as gray iron)

The carbon in the gray cast iron is mainly in the form of flake graphite, Iron Casting and the fracture is gray. Gray cast iron has a good casting performance and cutting performance, and low prices, easy manufacturing, and thus more widely used.

3. Ma mouth cast iron (referred to as Ma mouth iron)

Ma cast iron in the form of cement in the form of cement, Iron Casting and graphite state exists. Fracture to mixed with white light of the free cementite and dark gray graphite, it is called Ma mouth iron. Production rarely used Ma mouth iron.

Iron Casting According to the different shapes of graphite, cast iron is divided into the following four:

(1) gray cast iron, cast iron in the shape of graphite was sheet.

(2) Vermicular graphite cast iron in the majority of the cable is short worm-like

(3) ductile iron (also known as Ma iron, Magang), cast iron in the graphite is irregular group flocculent.

(4) ductile iron: cast iron in the graphite was spherical.