Study On Preparation Technology Of Low Alloy Wear-resisting Steel For Hammer Of Large Hammer Crusher

Along with our country economic development,the domestic motor vehicle ownership increases year by year,is now up to 372 million vehicles,including cars occupy 281 million vehicles,the scale of motor vehicles will face obsolescence,big hammer crusher is more suitable for crushing like automobile body lightweight metal,crushing efficiency is significantly higher than other crusher.Crusher hammer head is the key core component of large hammer crusher.In the crushing process,the hammer head is used to hammer the material repeatedly to make it broken to the specified small size.In the actual production process,due to the bad service condition of the crusher hammer head,it is easy to wear parts.If the hammer head is replaced frequently,it will seriously improve the production cost and reduce the production efficiency of the enterprise.Therefore,it is of great significance to improve the wear resistance of the hammer head of large hammer crusher.In this paper,the preparation process of ZG30Cr2 MnSiMoNi low alloy wear resistant steel used for the hammer head of large hammer crusher is studied.The influence of mechanical vibration time and heat treatment process in the casting process on the microstructure,mechanical properties and wear resistance of low alloy wear resistant steel is studied,and the typical low alloy wear resistant steel abroad is compared.The results show that the overall properties of the cast steel after mechanical vibration(2 min)are good.The microstructure of the cast steel is pearlite and a small amount of carbide,and the average grain size is 129.192 ?m.The mechanical vibration plays a role in refining grain.The tensile strength of the steel is 1027.1 MPa,and the wear resistance of the impact abrasive under 1J and 4.5 J impact energy is increased by 9.4 % and 3.3 %,respectively,compared with that of the as-cast steel without vibration.After 1020 ? normalization + 930 ? PAG quenching + 330 ?tempering,the microstructure of the steel is finer,and the microstructure is a mixture of tempered lath martensite and lamellar martensite with a small amount of carbide in it..The average width of the matrix is 156.7nm.The hardness of the steel after heat treatment is 51.1 HRC,and the energy absorbed by V-notch impact is 7.4 J.The tensile strength is 1663.8 MPa,and the wear resistance of impact abrasive under 1 J and 4.5 J impact energy is increased by 3.2 % and 22 %,respectively,compared with that of steel after 1020 ? normalizing + 930 ? water glass quenching + 330 ?tempering.The comprehensive properties of PAG steels quenched by water solution are slightly better than those of steels quenched by water glass solution.The microstructure of typical foreign low alloy wear-resisting steels ZG50Ni2 Si Cr Mo and ZG50Ni2Si2 Cr Mo are a mixture of tempered lath martensite and lamellar martensite with a small amount of carbide in it,the average matrix size is 61.4 nm and 47.5 nm,respectively,and the grains are fine.The hardness,impact absorption energy and tensile strength of the steel are 55.3 HRC,6.95 J,1695.0 MPa and 57.3 HRC,7.0 J,1912.7 MPa,respectively.The impact wear resistance of ZG50Ni2Si2 Cr Mo steel is 13.7 % and3.6 % higher than that of ZG50Ni2 Si Cr Mo steel under 1 J and 4.5 J impact energy.The hardness of ZG30Cr2 MnSiMoNi low alloy wear resistant steel with good comprehensive properties developed in this project reaches 92.4 % of ZG50Ni2 Si Cr Mo steel and 89.2 % of ZG50Ni2Si2 Cr Mo steel,and the impact absorption energy is increased by 6.5 % than that of ZG50Ni2 Si Cr Mo steel.Compared with ZG50Ni2Si2 Cr Mo steel,the tensile strength reaches 98.2 %of ZG50Ni2 Si Cr Mo steel and 87 % of ZG50Ni2Si2 Cr Mo steel.The impact wear resistance of ZG50Ni2 Si Cr Mo steel and ZG50Ni2Si2 Cr Mo steel are 94.3 % and 73.6 %,respectively,and 82.9 %and 71 %,respectively,under 1 J and 4.5 J impact energy.The hardness,strength and wear resistance of typical foreign low alloy wear-resisting steels ZG50Ni2 Si Cr Mo and ZG50Ni2Si2 Cr Mo are better than those of domestic ZG30Cr2 MnSiMoNi steels,but the impact toughness is worse,because the carbon content of these two kinds of typical foreign low alloy wear-resisting steels is higher.The typical foreign low alloy wear-resisting steels used in the manufacture of hammer heads of large hammer crushers have certain advantages in the low impact working conditions,but in the high impact working conditions,the ZG30Cr2 MnSiMoNi steel in China is not easy to fracture and the safety performance is better guaranteed.