高强塑积差厚钢板的组织性能控制机理研究

The tailor rolled blank (TRB) produced by cold rolling has some advantages of saving materials and reducing weight, decreasing welds, cutting costs, which is widely paid attention. At present, the development and research of TRB with large product of strength and elongation is still vacant. The technical ideas are proposed in the project, that the TRB with large product of strength and elongation is obtained by the difference heat treatment. The research to carry out is as follows: 1) The research on the principle and method of difference heat treatment of TRB with large product of strength and elongation is carried out. The tactics of difference heat treatment on thick area, thin area and transition zone of TRB is proposed. 2) The best technical measures to achieve the TRB with large product of strength and elongation are explored. By the separate area difference heat treatment on quenching, carbon partitioning and aging，the phase composition, morphology, content of different parts in the TRB product are controlled. The corresponding relationships between the difference heat treatment parameters and the microstructure and properties of TRB can be established. 3) The temperature field, stress and strain fields and microstructure field of TRB during difference heat treatment are simulated by FEM and CA, and the difference heat treatment parameters of the separate area are optimized. 4) By the difference heat treatment experiments, the above model is verified and optimized, so that the sample of TRB with large product of strength and elongation more than 30GPa% is obtained, and the strength and elongation can be separately controlled. The new method of the separate area difference heat treatment of TRB is established by this study, and the foundation is settled in order to promote application of TRB in the lightweight automobile.

冷轧差厚板具有节材减重、减少焊缝、降低成本等优点，近年引起人们关注。目前高强塑积差厚板研发尚属空白。本申请提出利用分区差别热处理方法来获得高强塑积差厚板技术思路，拟开展如下研究：1）开展高强塑积差厚钢板分区差别热处理原理与方法研究，提出周期性连续变化的厚区、薄区、过渡区的差别热处理策略；2）探究获得高强塑积差厚板最佳技术措施，通过分区差别淬火、碳配分和时效，控制产品不同部位的相组成、形貌、含量，建立差别热处理参数与组织性能对应关系模型；3）利用有限元及元胞自动机方法对差厚板分区差别热处理过程的温度场、应力应变场和组织场进行数值模拟，优化分区热处理参数；4）进行高强塑积差厚板分区差别热处理实验研究，对建立的模型进行验证和调优，获得强塑积超过30GPa%、强度和塑性分区可控的差厚板系列样件。通过本研究，确立高强塑积冷轧差厚板分区差别热处理新方法，推进国产高强度高塑性差厚板在汽车轻量化中的应用。

变厚度板带具有节材减重、减少焊缝、降低成本等优点，应用于汽车、桥梁、造船等。本项目针对冷轧高强塑积差厚钢板的差别热处理方法及组织性能控制技术开展研究，完成了项目计划书的各项内容，取得了如下研究成果：1) 利用有限元及元胞自动机方法，对高强塑积差厚板分区差别热处理过程中的温度场、应力应变场和组织场进行了数值模拟，优化了分区热处理参数，为高强塑积差厚板分区差别热处理工艺的制定提供参考。2) 针对冷轧高强塑积差厚钢板组织性能差异性的特点，分析研究了厚区、薄区、过渡区的差别热处理方法与策略, 建立了高强塑积差厚板差别热处理参数与组织性能对应关系模型。3) 针对冷轧双相钢、热冲压成形钢、Q&P钢、中锰钢差厚板4个钢种的分区差别热处理过程开展实验研究，得到了控制不同部位相组成、形貌、含量等的最佳技术措施。获得了强塑积超过30GPa%、最大值可达45.6GPa%的不同厚度区性能可控的差厚板样件，为加快推进国产高强塑积差厚板在汽车轻量化中的应用奠定了基础。4) 完成了项目量化指标：发表了学术论文5篇；获得4项发明专利授权；培养研究生6人，其中1人获得博士学位；参与起草了行业标准1项，并获得汽车工程学会优秀标准项目奖；相关研究成果已经获得教育部技术发明二等奖1项，辽宁省科学技术进步奖二等奖1项。