A Comparative Study On Wear Resistance Of 400 HB Martensite And Bainite Wear-resistant Steel

In this paper, 400 HB grades of martensite wear-resistant steel(NM400) and bainite wearresistant steel(NR400) were mainly researched, at the same time 450 HB grades of martensite wear-resistant steel(NM450) was comparatively studied. The microstructure of three test steels were observed by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and transmission electron microscopy(TEM) and other equipments. The performance testing includes polarization curves test and surface hardness test. The wear characteristics of martensite wear-resistant steel and bainite wear-resistant steel under different wear conditions were comparatively studied by sliding wear test, high temperature pin-on-disk wear test, impact wear test and corrosive abrasion wear test. The difference of wear resistance were mainly researched. The wear mechanism was analysised, and the connection between organization, mechanical properties and wear resistance was explored.The test results show that: the microstructure of martensite wear-resistant steel is mainly lathy martensite after quenched and tempered, carbide particles dispersed inside the lath and gap,the microstructure of NM450 steel is finer than that of NM400. The organization of bainite wear-resistant steel after hot rolled and low temperature tempered is mainly composed of carbide-free ferrite laths and thin retained austenite.The hardness of three kinds of wear-resistant steel plates is basically uniform from the surface to the core. NM450 steel has highest hardness(the average hardness is 44.4 HRC),NM400 and NR400 have about the same hardness(the average hardness is 40.7 HRC, 40.4HRC). Bainite wear-resistant steel(NR400) has better corrosion resistance than martensite wear-resistant steel(NM400, NM450).Under the sliding wear and impact wear conditions, the order of relative wear resistance is NM450>NR400>NM400. While under the high temperature pin-on-disc wear and corrosion wear conditions, the order of relative wear resistance is NR400>NM450>NM400, the relative wear resistance of NR400 steel is slightly different from the NM450. Under sliding wear condition, the main wear mechanism of wear resistant steel is microcutting when the load is low.With the load increasing, the wear mechanism turns into microcutting and fatigue failure.Compared with sliding wear, wear surface damage was much more worse under hightemperature wear condition. Worn surface has a large area of peeling, wear mechanism are oxidation wear and adhesive wear. Under the condition of impact wear, wear is caused by microcutting and fatigue mechanism. The main mechanism for corrosive and abrasive wear is the interaction between corrosion and wear. The research shows that the wear performance of wear-resistant steels(such as NR400 and NM400) are different under different wear conditions,even if their hardness are equal. The research content of this paper provides a good reference for the practical application of wear-resistant steel under different conditions.