Bucket Teeth With The Optimization Of Low Alloy Steel Heat Treatment Process

Excavator is widely used in mining exploitation and earthwork construction, such as housing construction, road construction, water conservancy construction, port construction, national defense project and so on. Dipper-tooth is a key wear-easy part of excavator. Dipper-tooth is needed to directly fight with mineral, rock-soil, and sandstone et al,which results in a mass of consumption of dipper-tooth. Conventional dipper-tooth is molded by casting, while forging dipper-tooth is being developed recently in commercial application, which is expected to have the good balance of the strength (and/or the hardness), the toughness and the wear resistance, with two times service life more than the usual casting dipper.On the basis of analyzing microstructure、mechanical properties and different work and digging conditions, low alloy steels40Cr and42CrMo which be used to make the forging dipper-tooth are carried out the following technology research:The low alloy experiment steel40Cr was proceeded by the technology partially used the forging-remnant-heat for the subsequent heat treatment which cut off microstructure heredity of forging and can obtain the same mechanical property with conventional technology of the hot forging followed by a subsequent heat treatment. Simultaneously, it need not reheat from room temperature and directly use the forging remnant heat partially for the subsequent heat treatment, this novel P-FRHH technology provides a lower economical cost approach in line with the low carbon economy trends.The low alloy experiment steel42CrMo was carried out a "zero hold time " quenching technology. This technology can obtain two different microstructure between the surface and the heart of the same sample. the surface microstructure is strips martensite and the heart microstructure is sorbide which can obtain good balance of toughness and wear resistant property.The low alloy experiment steel42CrMo was conducted by tempering at different temperature from430℃to510℃, metallographic microscope and durometer hardness was used to test microstructure and mechanical properties. Take into account work and digging conditions and performance requirement,430℃is the appropriate temperature at which it not only obtains high hardness, but has good impact energy as well.