以Q235B钢坯为试验原材料,分别设计了三种不同的喷射冷却水流密度。采用控制冷却工艺热轧制了规格为H200 mm×100 mm的H型钢。用金相显微镜和显微硬度计对H型钢金相组织和显微硬度进行了测试,使用万能试验机检测了H型钢拉伸性能。结果表明,随着水流密度增加,H型钢组织中铁素体含量减少,珠光体含量增加,晶粒明显细化,珠光体层片细小弥散。当水流密度增加到22.6 L/(m2·s)时,显微组织中还出现了少量的贝氏体强化相,H型钢显微硬度明显上升;终冷温度呈加速下降的趋势,屈服强度和抗拉强度则呈加速上升的趋势,伸长率随水流密度的增加而加速下降。 Taking Q235B billet as raw material, three different jet cooling water flow densities were designed respectively. Hot-rolled H-beams of size H200 mm × 100 mm were produced by controlled cooling. The metallographic microstructure and microhardness of H-section steel were tested by optical microscope and microhardness tester. The tensile properties of H-section steel were tested by universal testing machine. The results show that with the increase of water flow density, the content of ferrite decreases, the content of pearlite increases, the grains are obviously refined and the pearlite layer is finely dispersed. When the water current density increased to 22.6 L / (m2 · s), a small amount of bainite phase appeared in the microstructure, and the microhardness of H-shaped steel increased obviously. The final cooling temperature showed an accelerated decreasing trend. The yield strength and Tensile strength is accelerated upward trend, elongation with the increase of water flow density and accelerated decline.