∅160 mm非调质钢棒材的显微组织和疲劳性能

Microstructure and Fatigue Behavior of Non-Quenched-and-Tempered Steel Bar 160 mm in Diameter

采用控轧控冷技术生产了直径为160 mm,含0.41%C、0.60%Si、1.41%Mn、0.16%Cr、0.07%V和0.023%Nb(质量分数)的可直接机加工的非调质钢棒材。通过金相检验、疲劳试验和力学性能测定等研究了棒材的显微组织、力学性能和疲劳性能。结果表明:棒材表面至距表面40 mm处的晶粒度为8.5~10.0级,显微组织为珠光体和铁素体,珠光体片层间距为170~220 nm;棒材抗拉强度为1002 MPa,屈服强度为755 MPa,断后伸长率为18%,断面收缩率为48%,棒材距表面25 mm处的疲劳强度为502 MPa。

160-mm-diam non-quenched-and-tempered steel bar,containing 0.41%C,0.60%Si,1.41%Mn,0.16%Cr,0.07%V and 0.023%Nb by mass and being enabled to be directly machined,was produced by a controlled rolling and controlled cooling technology.The microstructure,mechanical properties and fatigue behavior of the bar were investigated by means of metallographic examination,mechanical property measurements and fatigue test.The results showed that(a)the grain sizes of region from the surface to 40 mm from the surface in the bar were grade 8.5 to 10.0,the microstructure consisted of pearlite and ferrite,and the lamellar interval of pearlite ranged from 170 to 220 nm,and(b)the bar exhibited mechanical properties such as tensile strength of 1002 MPa,yield strength of 755 MPa,elongation of 18%and reduction of area of 48%,and the fatigue strength at 25 mm from the bar surface was 502 MPa.