| For the low alloy wear-resistant steel working at abrasive wear, not only high hardness and high tenacity, but also good wear resistance are required to meet the demand for their performance. According to the working condition and the failure analysis of the bucket tooth, this paper designs five groups of composition of the low alloy wear-resistant steel. The content of C, Mn, and Si are almost the same, but the Cr content is different. Determined by the end-quenching curve, TTT curve, CCT curve of the experimental steels, we made different heat-treatment methods through it, including water quenching, normalizing and isothermal quenching. The microstructures of the low alloy wear-resistant steel at as-cast and after heat treatment were analyzed through the metallographic observing. The influences of Cr on microstructure and mechanical properties of experiment material were researched. Hardness, Impact Toughness, tensile strength and yield strength were tested. The influence of Cr and heat-treatment methods to the microstructure and mechanical properties of the experiment were studied on.The experiment results are below: The hardness was increased but impact toughness decreased as to risen the content of Cr. The microstructure made up of lath martensite and retained austenite, when the experimental steels water quenching. The lath-like of martensite turned more short and thick and the films of retained austenite turned thicker than before, as the content of Cr increased. The microstructure made up of ferrite net, bainite and retained austenite, when the experimental steels normalizing. The ferrite net became smaller than before, as the content of Cr increased. The microstructure made up of pro-eutectoid ferrite and bainite, when the experimental steels isothermal quenching. The ferrite net broken and disappeared, and the lath-like of bainte became more short and thick, as the content of Cr increased. The experiment steels of DH4, DH5, and DH6 had a better hardness and impact toughness than those of DH2 and DH3, when they water quenching. The experiment steel of DH5 have better combinative properties at AC3+100℃austenitizing water cooling and tempering at 300℃,δb=1650Mpa,δS=1450Mpa,αku =83J/cm2 HRC=48.2.The experiment steel of DH5 has good strength and toughness normalizing at AC3+75℃,δb =1230Mpa,δS =950Mpa,αku =45J J/cm2 HRC=43.The toughness of isothermal quenching on DH6 is much less than that of water quenching and normalizing at AC3+75℃, as the proeutetoid ferrite turn-up. The writer considers that experimental steel has the good combinative properties to resist the high-low-medium stress abrasion through different treatment technology.The innovated point in this paper is that we have researched a new type wear-resistant steel, which just added the bargain price of Mn, Si and less than 2.5 wt% Cr. The steel has good combinative properties to resist the high-low-medium stress abrasion through water quenching, normalizing and isothermal quenching.
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