Study On The Improvement In Hardness And Abrasion Resistance Of42CrMo Steel

In the recent30years, national economy and equipment manufacturing industry arerapidly developing, which has put forward higher requirements and performance indicators forthe demand of varieties of mechanical components both in quality and in quantity. It is asignificant issue related to economic sustainable development to seek well-performance steelswhich can meet industry demands. It is a pivotal procedure to get the best ratio of chemicalcomposition. The article is based on42CrMo alloy steel, adjust the composition ratio of alloyelements Cr, Mo, Nb, use three factors three levels orthogonal experiment research method,using rockwell hardness(HRC), abrasive wear tester MLD-100type combined withmetallographic microscope, scanning electron microscopy and energy spectrum analysis studythe influence of the content of alloy elements on hardness、wear rate and metallographicstructure of42CrMo alloy steel.The result proves that the optimal ratio of alloy elements Cr, Mo, Nb that add to42CrMoalloy steel are2.0%,1.2%,0.6%, the hardness value of as-cast42CrMo alloy steel is52.85HRC and it’s wear rate value is0.673. Further optimize the experiment, we can get thatthe hardness value of as-cast42CrMo alloy steel is52.96HRC and it’s wear rate value is0.566,the hardness value of rolled42CrMo alloy steel is60.9HRC and it’s wear rate value is0.493.As the ratios of alloy elements Mo and Nb increase, the hardness of samples also increase, buttheir wear rate value decrease, the wear-resisting performance of alloy steel is improved. Theeffect of Nb on hardness and wear rate value is more obvious. When the content of Nb is0.8%,the hardness value of as-cast42CrMo alloy steel is53.34HRC and it’s wear rate value is0.562,the hardness value of rolled42CrMo alloy steel is up to61.94HRC and it’s wear rate value is0.484. From the analysis we can draw a conclusion that Nb exists in NbC mesh structure,playing the role of the grain boundary strengthening and “skeleton”, and that themetallographic structure is martensite. All these are the main reasons why the hardness andwear rate of42CrMo alloy steel can be increased.