1. Malleable cast iron is a kind of cast iron obtained […]
1. Malleable cast iron is a kind of cast iron obtained by graphitizing annealing treatment of white cast iron. Because the graphite in malleable cast iron is flocculent, it has little effect on the cutting of the matrix, so its mechanical properties are higher than gray cast iron, wear resistance and Vibration damping is superior to ordinary carbon steel. This cast iron has a certain plasticity and toughness. It should be pointed out that malleable cast iron cannot be forged and pressed, it is just a name.
2. Malleable cast iron is divided into: ferrite malleable cast iron, pearlite malleable cast iron and white heart malleable cast iron. Among them, pearlite malleable cast iron has relatively high performance, and can replace some steel types for making crankshafts, gears and other parts that require wear resistance.
Ferrite malleable cast iron is generally used to make pipeline accessories, pipeline connectors and medium and low pressure valves. White heart malleable cast iron is mostly used for thin-walled shell parts, with good weldability and toughness.
Why malleable cast iron is only suitable for thin-walled parts
To produce malleable cast iron, white cast iron parts must be obtained first. After heat treatment, the white cast iron makes graphite agglomerate flocculent into malleable cast iron. If the wall thickness of the casting is large, the graphite at the thick wall may crystallize into flake graphite during the cooling process and become gray cast iron. It is impossible to become malleable cast iron by heat treatment.