Research On Wear Resistance And Grinding Work Hardening Mechanism Of ZGMn13 Steel

High manganese steel is of a good abrasion resistance and toughness as a wear-resistant metal material. It has been widely used in mining field, building materials field, electric power field, machinery field and metallurgical dustries field. It plays an irreplaceable role especially in high impact and high stress abrasive wear conditions. As we know the good wear resistance of the high manganese steel is achieved by its superior characteristics of work hardening, so the study on water toughening treatment of high manganese steel and its mechanism of work hardening is of great academic value and practical significance.In this paper, the hardness test, impact toughness test, metallographic analysis, X ray diffraction analysis and scanning electron microscope analysis method were used. It had reseached the influlence of water toughening treatment parameters on microstructure and properties of ZGMn13 steel casting with different thickness. Besides it had considerd the effect of load, reciprocating speed and wear time on friction and wear behaviors under dry friction conditions. Moreover its wear mechanism had analysised. Based on the roll working of high manganese steel in actual production, we discussed the hardening mechanism of high manganese steel were effected by grinding hardening.The experimental results show that:The optimum water toughening parameters of ZGMn13 steel were as follows: The holding temperature of water toughening treatment should vary in the range of 1050±25 ℃, and the temperature of water quenching should be lower than 40℃. The holding time of high manganese steel with a thickness of 10 mm should be keep 60min, and the holding time should be extended for 30 min to the each 10 mm increase of thickness. A high holding temperature would lead to serious decarburization, demanganization and oxidation on sample surface. While a high water quenching temperature would result in precipitation of the carbide which have dissolved in the austenite during the cooling process.The hardness of materials had significant effect on friction and wear properties of ZGMn13 steel. With the increase of high manganese steel material hardness, the wear mass loss was of a linear decline. The wear mass loss of water toughening treated high manganese steel increased with the amplify of load, reciprocating speed and wear time. In addition the friction coefficient minished by the amplify of load, reciprocating speed, but decreased by the magnify of wear time. In mild wear stage the wear mechanism of high manganese steel was main of yield abrasive wear, While in severe wear stage it was main of peeling abrasive wear. Otherwise there were oxidation wear, adhesive wear and fatigue wear happened in the two wear stage.By grinding, hardening phenomenon appeared in the surface of ZGMn13 steel. With grinding depth increases or longitudinal feeds decreased, the hardness of surface after grinding is enlargement. The hardening layer of water toughening treatment specimen was thicker than those non-treated specimen. The hardening layer thickness of former was greater than 0.5 mm, while the latter was between 0.3 mm and 0.4 mm. Microstructure of high manganese steel grinding section showed that it appeared a lot of slip line along 45° direction. So the surface of high manganese steel undergone plastic deformation, and many dislocation slips were appeared on it. Phase analysis of high manganese steel specimens showed that there was no martensite in the organizaition but only CFe15.1 of austenite structure before grinding. But when be ground, the hardened layer could find CFe15.1 of austenite structure and C0.12Fe1.88 of martensite structure. Therefore, the grinding hardening of high manganese steel were effected by dislocation hardening, twins hardening and martensite phase transformation hardening synthetically.