| HB400hardness grade of martensitic wear resistant steel (NM400) and bainite wearresistant steel (NB400) were studied in this paper. Firstly, the CCT curves of NM400steeland NB400steel were calculated by JMatPro software, then the organizations and hardnessof two wear resistant steels were studied by the heat treatment process, two kinds of400HB hardness grade wear resistant steels were produced by the optimum process, thewear resistance of martensite wear resistant steel and bainite wear resistant steel wasstudied in the silding wear and impact wear conditions. Last, the organizations andhardness and wear properties of NM400and NB400wear resistant steel plate productswere siudied.The CCT curves show that NB400wear resisting steel has higher hardenability thanNM400wear resisting steel.The actual heat treatment process show that, bainite is obtainedfor NB400steel in the air cooling condition, the hardness is accord with the requirement ofwear resistant steel, ferrite and bainite are obtained for NM400steel in the air coolingcondition, that the hardness is too low to meet the requirements of wear resistantsteel.NM400steel using water quenching after900℃austenitizing insulation and200℃tempering for the400HB grade of martensitic wear resistant steel, NB400steel using aircooling after920℃austenitizing insulation and300℃tempering for the400HB grade ofbainite wear resistant steel.Wear test results show that, martensite wear resistant steel has better wear resistancethan bainite wear resistant steel in the silding wear mode. The wear mechanism is thecutting mechanism, brittle flaking exist in the wear surface of martensite wear resistantsteel, fatigue crack exist in the wear surface of bainite wear resistant steel; The wearmechanisms are scratch abrasive wear and chisel cutting abrasive wear in the impact wearcondition, martensite wear resistant steel has better wear resistance than bainite wearresistant steel in the low impact wear condition, bainite wear resistant steel has better wearresistance than martensite wear resistant steel in the high impact wear condition, highimpact makes the residual austenite phase change into martensite, that improve the hardening layer hardness, and enhance the wear resistance of the material.Organizations and wear properties of NM400and NB400wear resistant steel plateproducts were siudied,the results show that,organization of NB400is banite lath andNM400is martensite lath.Wear resistance of NM400steel plate product increased by13percent than NB400steel plate product under the condition of the sliding wear of200Nload, wear resistance of NM400steel plate product increased by21percent than NB400steel plate product under the condition of the sliding wear of500N load,wear resistance ofNM400steel plate product increased by15percent than NB400steel plate product underthe condition of the impact wear of0.5J impact energy, wear resistance of NB400steelplate product increased by18percent than NM400steel plate product under the conditionof the impact wear of4J impact energy. |
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