| Hammer crusher is widely used in the fields of the mine, cement, metallurgy, electric power, refractory, glass and chemical industry, etc. As one of the key replacement part, a suit of hammers must be changed in less then a few days or more then several months because of the serious wear. Therefore, many manpower and material resources are caused to be wasted. So, the user begins to pay more attention to improve the friction durability of the hammers. In this paper, the duplex metal liquidliquid composite technologies have been developed to produce the high wearresistance, high toughness and low cost products. Not only guarantee the nice wear resistance for the hammers, but also substantially raise the shock resistance.Sand casting methods have been adopted to produce the duplex metal liquidliquid composite hammer and plate hammer. The high Cr cast iron is used as the wearing layer, as well as the 35 Cr Mo steel is used as the based layer. When the hammer is cased, the hammers handles are downwards as well as the heads are upwards. The quantitative 35 CrMo steel is poured firstly; after adequate retention time, the high Cr cast iron is poured to the cavity. Therefore, the favorable metallurgical bonding has been realized between the two-layer metal. For the plate hammers casting, three layers pouring technology should be used because the wear-resistance layers is outwards. The bottom layer is high Cr cast iron; as well as the connection layer is low alloy steel, and the top layer is high Cr cast iron. Three layers need to be poured at regular hours and in a fixed quantity. Both of molten metal should be inoculation treatment. One, the morphologies and distributions of the carbide of the high Cr cast iron could be improved. On the other hand, the grain degree of the low alloy steel could be refined; therefore, the grain would not be coarsened during high temperature treatment. The heat treatment of the composite hammer is heated to 950-980℃, air cooled. Therefore, the wear resistance layer possessed the high hardness and high wear resistance because of in the quench condition. Moreover, the based layer possessed the properties of high strength and toughness because of in the normalizing condition.The key technical indexes of the composite hammer are as follows. The hardness of the high Cr cast iron is equal or greater than 58 HRC, the toughness is equal or greater than 7J/cm2. The wear resistance and service life are more 2.5-5 times than that of the Mn13. the toughness and cost are less than the whole high Cr cast iron hammer.The key innovation of the composite hammer is as follows. Firstly, the formative technology of non-boxes and core assembly possessed the high production efficiency and maneuverability. Secondly, the duplex metal three time pouring technology is first used to produce the plate hammer, and the technological problem has been broken through. Thirdly, a pouring gate is shared for both of metal to produce composite hammer. Fourthly, the favorable metallurgical bonding has been realized for both of metal. Therefore, the interfacial strength improves 1.3-1.5 times than that of the solidliquid composite. Finally, the consume of the precious metal has been sharply reduced and the produce cost is less than 30%... |
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