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Powder metallurgies have unique chemical compositions, mechanical properties and physical properties. These properties can not be obtained by traditional casting methods. Porous, semi-dense or fully dense metal materials can be made by powder metallurgy technology, such as oil bearings, gears, cams, guide bar and tools. It is a little or non cutting process. Powder metallurgy technology can minimize the alloy composition segregation, the elimination of coarse, uneven casting organization. It plays an important role in the preparation of high-performance rare earth permanent magnetic materials, rare earth hydrogen storage materials, luminescent materials, rare earth catalysts, high temperature superconducting materials, new type of metal powder materials such as nickel powder and iron powder. Powder metallurgy of amorphous, microcrystalline, quasicrystals, nanocrystalline supersaturated solid solution such as a series of high-performance non-equilibrium materials, these materials have excellent electrical, magnetic, optical and mechanical properties. Can easily achieve various types compound, give full play to the characteristics of each group element material is a low-cost production of high-performance metal powder and ceramic composite materials technology. Powder metallurgy can produce ordinary melting method can not be produced with a special structure and properties of materials and products, such as a new type of porous biomaterials, porous membrane materials, high-performance structural ceramic abrasive and functional ceramic materials. Can also take advantage of the ore, tailings, and steelmaking sludge rolled steel scales, recycling scrap metal as raw material, is an effective material recycling and comprehensive utilization of new technologies. Common machining tools, metal abrasive, a lot of powder metallurgy technology manufacturing. Cast iron according to the color of the fracture: most of the carbon in gray cast iron or all of flake graphite exists in the form of free states, the fracture was dark gray, with a certain amount of mechanical properties and good cutting performance, generally used in industry. White cast iron is the organization have little or no graphite iron-carbon alloy, the fracture was bright white, hard and brittle, cutting can not be directly used to produce mechanical parts, very few in the industry. Due to its high surface hardness and wear resistance, also known as chilled cast iron or of chilled cast iron. Mottled cast iron is between a white cast iron and gray cast iron cast iron, the fracture was gray and white linen punctate, the performance is not good. It has very few applications. By chemical composition of ordinary cast iron is cast iron does not contain any alloying elements, such as gray cast iron, malleable iron, ductile iron, alloy cast iron, ordinary cast iron, adding some alloying elements to improve some specific properties The preparation of an advanced cast iron. Such as a variety of corrosion resistance, heat resistance, wear-resistant special properties of cast iron. Ordinary gray iron, the production methods and organizational performance and gave birth to the cast iron, which is on the basis of gray cast iron, from the "Modification", also known as the deterioration of cast iron. Its strength, ductility and toughness than the generally gray cast iron is much better organized and more uniform. It is mainly used in the manufacture of large castings and metal powder which have higher mechanical properties and great changes in section size. Malleable iron is made by a certain composition of white cast iron in graphitization annealing. It has a higher toughness than gray cast iron and is called ductile cast iron. It can not be forged and it is used to produce castings under impact loading. And the ductile iron is obtained by adding a certain amount to the liquid iron casting nodulizer and ink agent in order to promote globular graphite mold. Comparing to steel, in addition to slightly lower plasticity and toughness, other properties are closely. It is an excellent material with advantages of steel and cast iron. So it is widely used in mechanical engineering.Source:http://www.mhcmp.com
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