Malleable cast iron, also known as Ma iron or Ma steel, can not be forged, these names only mean that it has a certain plasticity δ = (2 ~ 12) % and toughness aKU ≤ 30J / cm2, it is called ductile iron or ductile iron.
The malleable iron is a kind of high strength white cast iron, which is made of white iron through the decomposition of cementite after annealing. There are two types of cast iron, black and white, according to the annealing method.
Black core malleable cast iron is obtained by graphitization annealing, while white core is prepared by oxidative decarbonization annealing. The latter is rarely produced, and China mainly produces black heart malleable iron.
Malleable steel pipe fittings are available in two colors, black and white.
Black pipe fittings are said to be finished black products, black products have been set of wire and heat treatment and simple surface rust, surface black is black.
Malleable steel pipe fittings after the surface of the galvanized pipe, then for white, also known as galvanized pipe fittings. Galvanized pipe fittings are divided into hot and cold plating, hot plating is to melt the zinc pipe in the melting pot all immersed, The inside and outside of the pipe fittings are coated with a layer of zinc, plated with a lot of zinc and 70um thick, hot plating Ma steel pipe fittings for fire, gas, the specifications are relatively high; Hot plating corresponds to cold plating, cold plating is divided into electroplating and baking plating, Cold plated pipe fittings galvanized layer thickness of about 10um, and cold plating pipe fittings plating surface, cold plating pipes are used for crafts pipe fittings, plumbing.