When the hammer crusher works, the abrasive enters the crusher cavity from the hopper, and the material is crushed by the impact of the high-speed rotating hammer; Or the material is thrown to the impact plate on the inner wall of the cylinder through the high-speed rotating material tray, and returns to the hammering area after collision, so that the material is crushed by the plate hammer.
At present, there are many kinds of materials for casting the hammer head of hammer crusher, such as casting high manganese steel series, casting alloy steel series and casting high chromium cast iron series. The actual production shows that the service performance of hammers with different materials is quite different, so the materials of hammers should be selected reasonably according to the service conditions of hammers.
At present, it is recognized that high chromium cast iron is the most wear-resistant alloy material. High chromium alloy hammer has the highest hardness, is a high-quality wear-resistant material, and has been widely used in hammer crusher. After heat treatment, the hardness of high chromium cast iron can reach more than 58HRC, the matrix is high hardness martensite, and the microstructure contains a lot of high hardness carbide M7C3, which is considered as an ideal wear-resistant material for crusher hammers. The microstructure and properties of wear-resistant hammer mainly depend on the contents of chromium, carbon and manganese. Because the affinity of carbon and chromium is greater than that of iron and carbon, a series of stable ferrochromium compounds are formed.
Compared with high manganese steel hammer, high chromium hammer has higher hardness and better wear resistance, and has been widely used. Because of the high content of chromium and carbon in the hammer, chromium is the element that forms the network carbide at the grain boundary, and a large number of * * crystal carbides are continuously distributed at the grain boundary, and the matrix is twin substructure martensite. This structure of continuous brittle network carbide distributed at the grain boundary of brittle and hard matrix leads to insufficient toughness reserve of hammer head and affects its application scope.
How to improve the toughness of high chromium hammer has become an important topic for crusher hammer manufacturers. As a wear-resistant material, it requires high hardness. However, in the process of wear, only the hardness of the material is pursued while the toughness of the material is ignored, which will inevitably lead to the peeling effect and even premature fracture of the hammer during use. How much is a ton of alloy hammer?
Composite alloy hammer casting-double alloy liquid-liquid composite-solid-liquid composite casting method can be adopted.
Liquid-liquid composite method is to obtain hammer head by integral casting. When casting, two furnaces should work at the same time and melt two kinds of metal materials at the same time. The hammer handle can be made of cast steel or alloy steel, such as ZG270-500 or ZG3 10-570. When the molten steel meets the requirements, the molten steel can be poured first after the deoxidation is good. After waiting for a certain time, the head and its riser are filled with molten iron of high chromium cast iron. In order to obtain good castings by liquid-liquid composite method, it is necessary to strictly control the pouring temperature after pouring molten steel and the waiting time for pouring molten iron, that is, after pouring the hammer handle, pour molten iron when the surface layer of molten steel to be poured on the handle has a certain thickness, so as to ensure that the poured molten steel is not mixed and the joint surface between steel and molten iron is good after solidification. It is worth noting that in the composite casting of high chromium cast iron and steel, the molten steel in the hammer handle should be poured first. If molten iron is poured first, it is difficult for molten steel and molten iron to obtain a good composite surface, and the joint area of the two materials is prone to defects such as slag inclusion and porosity.
Casting cemented carbide or high chromium cast iron rod to improve the service life of hammer head. The specific method is to put cemented carbide or high chromium cast iron rod into the hammer part of the cavity during molding, and then pour high manganese steel liquid to realize solid-liquid compounding. The wear resistance and service life of high manganese steel hammer can be effectively improved by embedding alloy with higher hardness in the hammer.
Hammer crusher is a common crushing equipment, in which the hammer head is the main wear-resistant component, and the wear resistance of the hammer head directly affects the production efficiency of the crusher. At present, the hammers of hammer crushers in China are mostly made of high manganese steel. Because high manganese steel has poor wear resistance and short service life, it needs to be replaced frequently, and its service life is less than half a year. It is urgent to replace the high chromium cast iron composite hammer. It is an ideal choice to use the patented product "super wear-resistant double alloy hammer" produced by Gongyi Chen Dong Industrial Co., Ltd.-double liquid bimetallic composite hammer. The main feature of this kind of alloy wear-resistant hammer is that the working part is made of high chromium alloy steel and the hammer handle is made of low alloy manganese steel. The two are metallurgically combined by "two-liquid composite", which greatly improves the wear resistance of the hammer. Chen Dong two-liquid alloy hammer is cast once, which will not fall off and is wear-resistant and efficient. The service life of Chen Dong alloy hammer is 3-5 times longer than that of the original product, and the crushing efficiency is improved by more than 30%. This hammer is widely used in limestone crushing, clinker crushing, shale crushing, coal gangue crushing, coke crushing, ore crushing and other industries in cement plants!