Heat Treatment Process And Group Of High Cr Microalloyed Wear Resistant Steel Study On Weaving Mechanical Properties

The wear-resistant steel in China is mainly high manganese steel.With the continuous development of wear-resistant steel and the harsh application conditions,the performance and service life of parts in some special occasions are difficult to meet the requirements,and have been dependent on imports.In view of the above problems,this thesis designed a new type of wear-resistant experimental steel as the main research object,and the domestic wear-resistant steel and foreign wear-resistant steel were compared and analyzed.Two thermal simulation schemes were designed by using Gleeble-3500D to simulate the forging process of the experimental steel.The effects of deformation,deformation rate and holding time on the microstructure of the experimental steel were analyzed.Four kinds of heat treatment processes were designed to heat treat the experimental steel after forging.The effects of each heat treatment process on the microstructure,properties and strengthening mechanism of the experimental steel were analyzed.The effects of different alloying elements on microstructure,properties and strengthening mechanism of wear resistant steels abroad and domestic were compared and analyzed.The results of thermal simulation experiment show that for other variables unchanged,when the deformation is only 30%,50%and 70%,the dislocation morphology and dislocation density of different deformation are analyzed by XRD.With the increase of deformation,the dislocation density increases from 3.11×10¹⁵m^-2corresponding to 30%deformation to 8.74×10¹⁵m^-2corresponding to 70%deformation.With the increase of deformation amount and deformation rate,the grain refinement and martensite+retained austenite transformation are more,the thickness of bainite lath is reduced by at least150nm,and the martensite+retained austenite transformation is increased by at least 10%.The change of holding time on the grain size and martensite+retained austenite content is small,bainite lath thickness is less than 30nm,martensite+retained austenite transformation is only less than 3%.The test results of mechanical and wear properties of experimental steel after heat treatment show that among the four heat treatment processes,the performance and microstructure of heat treatment process 4 are most in line with the needs of wear-resistant steel.The tensile strength reaches 1929MPa,the impact energy reaches 27.2J,and the strength-plastic product reaches 40.89GPa%.In terms of wear performance,the wear amount is 0.01g,and the average friction coefficient is 0.187.In terms of fracture morphology,tensile fracture morphology is ductile fracture,and impact fracture morphology is brittle fracture.The comparative analysis results of experimental steel and wear-resistant steel at home and abroad show that the tensile strength of wear-resistant steel at home and abroad reaches 1847MPa and 1643MPa respectively in terms of mechanical properties.the strong plastic product was 28.26GPa%and 15.27GPa%the impact energy reached 28.9J,20.2J.In terms of its wear performance,the wear amounts of wear-resistant steels in China and abroad are 0.02g and 0.04g,respectively.The average friction coefficients were 0.183 and0.202,respectively.The strength and hardness of experimental steel are higher than that of domestic wear-resistant steel,while the toughness of experimental steel is slightly lower than that of domestic wear-resistant steel.