Abstract: The production flowsheet of test steel SCM435 rod coil (/% ：0.33-0.38C, 0.15-0.35Si, 0.60-0.85Mn, ≤0.025P, ≤0.025S, 0.90-1.20Cr, 0.15-0.30Mo) is 80t BOF-LF-280 mm x325 mm casting bloom-160 mm x 160 mm hot-rolled billet-hot continuous rolling to Φ16 mm rod coil. The effect of 160 mm x 160 mm hot-rolled billet rolling to rod coil processes by normal rolling ( beginning rolling at 1060 °C , finishing rolling at 930-950℃ , finishing exit temperature 860-900℃ , cooling rate 0.5-0.6℃/s) and control-rolling-cooling (beginning rolling at 1060℃ , finishing rolling at 820-850°C , finishing exit temperature 780-820℃, cooling rate 0.4-0.5°C/s) on structure and mechanical properties of steel SCM435 hot-rolled rod coil has been tested and studied. Results show that with decreasing the finishing temperature and cooling rate, the structure of steel hot-rolled rod coil is improved and the tensile strength of steel decreases obviously, that is the average tensile strength of steel SCM435 hot-rolled rod coil rolled by normal rolling process is 952 MPa with structure of ferrite + pearlite + bainite + martensite, while the average tensile strength of SCM435 hot-rolled rod coil rolled by control rolling-cooling process is 817 MPa with structure of ferrite + pearlite. Based on the principle of control-rolling-cooling the analysis on change of structure and properties of steel has been carried out.

Key words: Steel SCM435, Φ16 mm Rod Coil, Control-Rolling-Cooling, Structure, Mechanical Properties

摘要： 试验钢SCM435（/%:0.33~0.38C,0.15~0.35Si,0.60~0.85Mn,≤0.025P,≤0.025S,0.90~1.20Cr,0.15~0.30Mo）盘条的生产流程为80t BOF-LF-280 mm×325 mm铸坯-160 mm×160 mm热轧坯-热连轧成Φ16 mm盘条。试验研究了160 mm×160 mm热轧坯由常规轧制工艺（开轧1060℃,精轧930~950℃,吐丝860~900℃,冷却速度0.5~0.6℃/s）和控轧控冷工艺（开轧1060℃,精轧820~850℃,吐丝780~820℃,冷却速度0.4~0.5℃/s）对SCM435钢热轧盘条组织和力学性能的影响。结果表明,随着精轧温度的降低和冷却速度的减小,钢热轧盘条的组织得到改善,抗拉强度明显降低;常规工艺轧制SCM435钢热轧盘条的抗拉强度平均952 MPa,组织为铁素体+珠光体+贝氏体+马氏体,控轧控冷工艺轧制的SCM435钢热轧盘条的抗拉强度平均817 MPa,组织为均匀的铁素体+珠光体。结合控轧控冷工艺原理对钢的组织和性能变化进行了分析。

关键词: SCM435钢, Φ16 mm盘条, 控轧控冷, 组织, 力学性能