980MPa级冷轧双相钢的组织性能研究.pdfVIP

980MPa级冷轧双相钢的组织性能研究 1 1 1 2 1 1 1 王科强 刘仁东 王 旭 韩启航 林 利 徐 鑫 孙建伦 (1.鞍钢股份有限公司技术中心，鞍山 114001; 2.北京科技大学材料科学与工程学院，北京 100083) 1 摘 要 在实验室试制了 980MPa 级 C-Si-Mn-Nb 系冷轧双相钢，试制钢的屈服强度为 476 MPa ，抗拉强度为 1021MPa，伸长率分别为 15%，n 值分别为 0.29，屈强比分别为0.47；试制钢的热轧组织为F+P ，铁素体的晶粒尺 寸约为 3.3μm ；退火组织为F+M，马氏体体积分数约为63% 。微合金元素Nb 的添加，起到细晶强化和析出强化的 作用，与热轧组织相比，连续退火板带状组织得到明显得到改善，试验钢表现出良好的强韧性匹配。热轧板和退火 板拉伸断口均为韧性断裂。 关键词 双相钢 力学性能 组织 断口形貌 MicrostructureandMechanicalPropertiesof980MPa ColdRolledDualPhaseSteel Wang Keqiang1 Liu Rendong1 Wang Xu1 Han Qihang2 Lin Li1 Xu Xin1 Sun Jianlun1 (1. Technology Center of Angang Steel Co., Ltd., Anshan ,114001; 2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083) Abstract 980MPa cold rolled dual phase steel has been developed by designing C-Si-Mn-Nb alloy systems. The yield strength, tensile strength, elongation, strain hardening exponent and yield ratio are 476MPa, 1021MPa, 15%, 0.29, and 0.47, respectively. The microstructure of as-rolled steel is ferrite and pearlite, and the ferrite grain size is approximately 3.3μm. By contrast, the microstructure of annealed steel is ferrite and martensite, and the volume fraction of martensite is 63%. Nb is added to refine crystal grains and lead to precipitation strengthening. Compared with the microstructure of as-rolled steel, the banded structure is improved in the annealed sheet. Therefore, the experimental steel performs favorable combination of strength and toughness. Both hot rolled and annealed steels display toughness failure. Key words dual phase steel, mechanical properties, microstructure, fracture morphology 1 引言 人们对汽车减重、节能、高安全性的更高要求和政府对相关法规的加严，先进高强钢在汽车上的应用逐 年增加。冷轧双相钢因具有