Study On Wear And Corrosion Of Hot Rolled Mn8,Mn15 And Mn18 Wear-resistant Steel

The traditional high manganese steel does not have the advantage under the medium and low load.On the basis of it,the medium manganese steel and superhigh manganese steel are produced by reducing or increasing the content of carbon and manganese elements,to some extent,which makes up for the disadvantages in the application.In this paper,the sliding and impact abrasive wear properties and mechanism of Mn8,Mn15 and Mn18 were studied and the electrochemical corrosion properties of three manganese steels were discussed under the environment of mine water.The main conclusions are as follows:Three kinds of manganese steels show more negative corrosion potential under acid mine water condition,therefore their corrosion resistance under acid condition is weaker than that under alkaline and neutral corrosion environment.On the other hand,the corrosion resistance of Mn8 is better than that of Mn15 and Mn18 in acid,medium and alkaline mine water environment.Since Mn8 has the most positive open-circuit potential(maximum),the largest corrosion voltage,the smallest corrosion current,and the smallest arc resistance.The sliding wear test shows that the friction coefficient of the three manganese steels increases rapidly at first,then decreases to a certain range and tends to be stable.What's more the average friction coefficient under low load is higher than that under high load.Mn8 has the lowest wear weight loss,and its wear resistance of sliding abrasive is better than that of Mn15 and Mn18 under the same condition of wear.The hardness distribution of the steel's wear layer presents the change of gradient.The hardness of Mn8 steel's wear subsurface layer(50um)reaches 550 HV,and that of Mn15 and Mn18 is 450 HV and 510 HV,respectively.As a consequence Mn8 has the best effect of work hardening,and Mn18 is superior to Mn15.The mechanism of dry friction of three wear-resisting steels is mainly adhesive wear,which is accompanied by fatiguespalling.in local area.The abrasive wear mechanism of quartz sand is mainly abrasive wear,which shows the phenomenon of wide and deep furrows and large area of fatiguespalling.The impacting wear testing results show that,the hardening ability of three manganese steels increases and the wear weight loss decreases obviously with the increase of impact energy.When the impact energy is 1.5J,the wear weight loss of Mn18 is lower than that of Mn8 and Mn15.When the impact energy is 3.5J,Mn8 has the lowest wear weight loss.Mn8 and Mn18 subsurface microstructure have relatively high density twins and the hardness of the subsurface(50um)reaches 50 HRC and 48 HRC,respectively.The work hardening effect of Mn8 and Mn18 is significantly better than that of Mn15.The wear forms of three manganese steels are mainly chiselcutting wear and fatigue spalling wear.The structures of Mn8 and Mn15 worn subsurface are mainly dislocation,twins and martensite,and the wear mechanism is martensite transformation composite strengthening.A large number of dislocations and twins appear in subsurface of the Mn18,and martensite transformation was not found.However,the segregation region of Fe-Mn-C atomic group appears in this testing condition,which was strengthened by the dislocations,twins and Fe-Mn-C atomic group.