轧后中冷温度对780 MPa级高扩孔钢组织与性能的影响

Effect of post-rolling intermediate cooling temperature on microstructure and mechanical properties of 780 MPa grade steel with high hole-expanding radio

对轧制后分阶段冷却中冷温度对780 MPa级高扩孔钢组织及其对性能的影响进行了研究。结果表明:中冷温度为560℃时,试验钢组织为单一粒状贝氏体;中冷温度为660℃时,试验钢组织为多边形铁素体和粒状贝氏体,有利于改善钢的韧性,可获得优异的综合力学性能:屈服强度705 MPa,抗拉强度808 MPa,伸长率为16.8%,扩孔率为93.3%。

Effect of post-rolling phased cooling intermediate cooling temperature on microstructure and mechanical properties of 780 MPa grade steel with high hole-expanding radio was studied. The results show that the microstructure of the tested steel with intermediate cooling temperature 580℃ consists of granular bainite only. With the intermediate cooling temperature 660 ℃, the microstructure of the tested steel consists of polygonal ferrite and granular bainite, which is beneficial to improve the toughness of the steel and can obtain excellent comprehensive mechanical properties： yield strength 705 MPa, tensile strength 808 MPa, elongation 16.8%, and ratio hole-expanding radio 93.3%.