Research On Heat Treatment Process Of High Manganese Steel And Impact Abrasive Wear

Wear is one of the three main reasons for failure of mechanical parts. Enormousloss of material and energy is caused by wear of varieties of mechanical parts. Lotsof resistant materials are used in departments of metallurgy, mining, building, coal,electric power, chemistry, agriculture and military and etc. The huge economic lossis primarily result from wearing.Due to excellent work hardening ability, high manganese steel is widely used asmanufacture wear-resistant parts working at condition of impact loading.Unfortunately, brittle fracture phenomenon occurs when some of the traditional highmanganese steel are on service at extreme cold environment. There will be corrosionwear in conditions of the high temperature or wet grinding. In order to overcome theshortcomings of the traditional high manganese steel, the alloyed high manganesesteel and super high manganese steel are designed by domestic and foreign scholars.This thesis focus on determining the optimum heat treatment process by studying theproperties of alloyed high manganese steel and high manganese steel processed bydifferent heat treatments. Providing reference for the actual conditions, the wearmechanisms at different impact energy were studied through experiments of impactabrasive wearing. The following conclusions are summarized as below:(1)By analyzing the microstructures of specimens produced by different heattreatment processes, we can confirm the best heat treatment process of the alloyedhigh manganese steel and super high manganese steel: Firstly, heating the specimenup to550℃and holding for1.5hours, secondly increasing temperature to650℃andkeeping for2hours, then heating up to1080℃and keeping for2hours, finallyquenching in water, the heat speed used in the whole process was100℃/h.Theultimate refined grain sizes are170um and100um respectively.(2)It can be found that the abrasion performance of alloyed high manganesesteel and super high manganese steel is the most excellent when they were workingunder the relative energy of200J/cm2.200J/cm2was the critical impact energy. Onlyworking in condition of higher impact energy beyond the critical one, could theyshow good abrasion performance.(3)When the relative impact energy was between50～100J/cm2, the wearmechanisms were cutting mechanism and plastic deformation wearing. When the relative impact energy was beyond the critical impact energy, their wear mechanismwas mainly pitting accompanied with parts of cutting and plastic deformationwearing.(4)By analyzing the microstructure of alloyed high manganese steel and highmanganese steel after compressive deformation, the slip line density in grainsincreased and multiple slip systems activated as deformation strain increased. Themechanism of work hardening is dislocation hardening mechanism.