Abstract: Tested 0.5 ~0.7Cr steel for bucket blade (/% : 0.22 ~ 0.30C, 0.25 ~ 0.45Si, 0.95~1.20Mn, 0.006 ~ 0.009P, 0.008 ~0.010S, 0.5 ~0. 7Cr, 0.015 ~0. 065Nb, 0 ~ 0. 040Ti) is melted by a 50 kg vacuum induction furnace and hot-rolled to 16mm plate with finished rolling temperature 850 ~ 900 °C , air cooling. The effect of Nb-Ti content (0. 015Nb, 0. 035Nb-0. OlOTi and 0. 065Nb-0. 040Ti) on structure and mechanical properties of hot-rolled steel for bucket blade has been studied by optical, scanning electron and transmission electron microscope and mechanical properties examination. Results show that the structure of tested steel is ferrite + pearlite ； with increasing Nb-Ti content in steel, the grain in steel plate is fined, the lamellar spacing of pearlite decreases and the amount of precipitates of (Nb, Ti) C and ( Nb, Ti) (C, N) and the strength increase； and the mechanical properties of steel plate containing 0. 065Nb-0. 040Ti is yield strength 632 MPa, tensile strength 916 MPa, elongation 17.7% , impact energy K_AV 40 J and HB hardness value 234.

摘要： 试验0.5~0.7Cr铲斗刀板型钢（/%:0.22~0.30C,0.25~0.45Si,0.95~1.20Mn,0.006~0.009P,0.008~0.010S,0.5~0.7Cr,0.015~0.065Nb,0~0.040Ti）由50kg真空感应炉熔炼,热轧成16mm厚板,终轧温度850~900℃,空冷。通过光学显微镜、扫描、透射电镜和力学性能测试研究了Nb-Ti含量（0.015Nb,0.035Nb-0.010Ti,0.065Nb-0.040Ti）对热轧态铲斗刀板钢组织和力学性能的影响。结果表明,试验钢组织为F+P,随Nb-Ti含量增加,钢板的晶粒细化,珠光体片层间距降低,（Nb,Ti）C和（Nb,Ti）(C,N)析出物增多,强度增加,0.065Nb-0.040Ti钢板的力学性能为屈服强度632MPa,抗拉强度916MPa,延伸率17.7%,K_AV40 J,HB硬度值234。