Effects Of Heat Treatment Process On Microstructures And Properties Of Low Alloy Wear Resistant Steel

Wear resistant steel is one of common materials and its dosage is great, each year thewear consumption of wear resistant steel more than1.5million tons, many research havebeen done to reduce wear. So studying the wear mechanism of the wear resistant steel toreduce the wear rate is of great significance.With steel plate for engineering machinery as the research object, a new type of highstrength low alloy wear-resistant steel was studied. In this paper, four groups ofComposition of low alloy wear resistant steel were designed, the content of Mn, Si, Cr, Ni,B, and Re are almost same, but C and Mo content are different, then samples werequenched at850℃,880℃,910℃,940℃and tempered at150℃,200℃,250℃,300℃.The as-cast structure of test steel and microstructure of samples after heat treatmentby metallographic microscope and scanning electron microscope, the precipitates of teststeel were analyzed by TEM, and rockwell hardness, impact toughness, tensile strength,yield strength and elongation were tested to determine the optimal composition of lowalloy wear resistant steel and the best heat treatment process.The experimental results show that the as-cast structure of low alloy wear resistantsteel is pearlite. The microstructure and properties of low alloy wear resistant steel are bestafter quenching at910℃/30min and tempering at200℃/1h, the microstructure are lathmartensite, acicular bainite, retained austenite and dispersed carbide, the hardness HRC52,impact toughness aK40J/cm~2, tensile strength is1580MPa, yield strength is1342MPa andelongation is5.7%. SEM impact fracture showed that it was ductile rupture and dimplewas deep. With the increase of quenching temperature, hardness and impact toughnessincreased and then decreased. The wear test showed that with the increase of hardness, thetest steel had better wear-resisting performance and wear mechanism is micro-cutting. Thesurface abrasion of the test steel was not serious, the cutting hole distribution was irregularand small size.Through the experiment, a new kind of low alloy wear resistant steel with good comprehensive mechanical properties was obtained.