22MnB5论文：22MnB5 热成形 加热保温时间 冷却速率 梯度硬度.doc

【关键词】22MnB5 热成形 加热保温时间 冷却速率 梯度硬度【英文关键词】22MnB5 Hot forming Heat preservation time cooling rate Gradient hardness22MnB5论文：车用高强度钢板热成形工艺参数实验研究【中文摘要】高强度钢板热成形技术是将金属热处理工艺技术和金属塑性成形理论相结合而发展起来的一项全新的成形技术。由于高强度钢板在汽车产业中的广泛应用，以及国外技术的垄断，因此，有关高强度钢板热成形技术的研究受到国家的大力支持与鼓励，同时受到学术界高度重视。高强度钢板热成形技术具有广阔的市场需求和强大的生命力。当今汽车产业向着绿色、环保、安全、高性能化发展，其中汽车轻量化是实现节能环保的重要途径之一。高强度钢板在汽车上的应用是实现汽车轻量化和节能减排的同时，又能提高汽车碰撞安全性。温度和冷却速率是影响高强度钢板热成形的重要因素，本文以22MnB5为研究对象，以不同的冷却速率对22MnB5组织和机械性能的影响为主题，研究了不同保温时间对22MnB5机械性能的影响，确定了22MnB5最佳的加热保温时间，对淬火后材料厚度方向上硬度实验发现材料在厚度方向上硬度呈现中间硬两边软的近似对称分布的金属复合结构，这种材料具有很好的吸能能力。在此基础上，对22MnB5板料在不同的冷却速率下进行淬火，通过拉伸实验、V形弯曲实验以及硬度和微观分析最终确定了厚度为2.0mm的板料在模具中最佳的冷却速率范围，得到了硬度和抗拉强度之间的关系。高强度钢板的抗拉强度以及屈服强度很高，但是其韧性很差，如何改善其韧性是其面临的又一重要课题，本文在以上实验的基础上对22MnB5不同区域实施不同的淬火方式，并对不同冷却速率的交界处即过渡区域，进行了力学实验以及硬度实验，发现这部分区域的硬度呈现梯度增加的趋势，即存在硬度梯度，发现这部分材料抗拉强度提高的同时韧性也保持较高的水平。该研究的重要意义是可以实现汽车不同区域具有不同的强度以及硬度的材料。最终确定了高强度钢板热成形技术中最佳的工艺参数，对热冲压实际生产过程起到了指导作用。【英文摘要】Hot forming technology of high strength steel is a new developed forming technology combined with metal heat treatment technology and metal plastic forming theory. Because of the high strength steel widely used in the automobile industry and the monopoly of foreign technology, so hot forming technology of high strength steel is strongly supported and encouraged by our country, as well as given great importance to attaches by the academic community. Hot forming technology of high strength steel has broad market demand and strongly vitality.Now, automobile industry is developed toward green, environmentally friendly, safe, high performance, and vehicle weight reduction is an important way to achieve energy saving and environmental protection. The high strength steel in automobile applications realizes automobile lightweight and energy saving, at the same time improves the vehicle crash safety. Temperature and cooling rate are important factors that impact hot forming of high strength steel,22MnB5is selected as the research object in this article. The theme is the effect of different cooling rates on22MnB5microstructure and mechanical properties. The optimal heat preservation time is determined by studying the impact of different holding time on the mechanical properties of22MnB5. Material thickness direction of hardness experiment after quenching found material hardness in the thickness direction showing the intermediate hard-soft on both sides of nearly symmetric distribution of metal composite structure.22MnB5sheet quenched under different cooling rates, ultimately the optimal cooling rate range of the thickness of2.0mm sheet in the mold is defined through tensile test, V-shaped bending test, hardness and microscopic analysis, meanwhile, the relationship between hardness and tensile strength is obtained. High strength steel has high tensile strength and yield strength but poor toughness. How to improve its toughness is another important topic. Quenching the different regions of22MnB5in different ways, the hardness of transition zone of the different cooling rates shows a gradient increasing trend through mechanical and hardness tests. The transition region material tensile strength increases while the toughness maintains a high level. The importance of the research realizes vehicle in different regions with materials of different strength and hardness. The optimum parameters of hot forming technology of high strength steel are determined and play a guiding role in the actual production process of hot forming.【目录】车用高强度钢板热成形工艺参数实验研究摘要4-5Abstract5-6目录7-10第一章 绪论10-241.1 引言10-161.1.1 热成形技术背景10-111.1.2 热冲压成形有关技术介绍11-121.1.3 热冲压成形技术中关键的设备介绍12-161.2 热冲压成形钢板国内外研究现状16-191.2.1 热成形国外研究现状17-181.2.2 热成形国内研究现状18-191.3 本课题来源以及研究内容的重要意义19-211.4 热成形技术课题主要的研内容21-24第二章 金属薄板热冲压成形原理24-302.1 高强度薄板冲压成形过程中的理论基础和技术特点24-262.1.1 冲压过程中金属塑性变形252.1.2 冲压工艺与汽车覆盖件25-262.2 热塑性变形机理及其对金属组织和性能的影响26-282.2.1 热成形过程中薄板塑性变形的原理26-272.2.2 热塑性变形对金属组织和性能的影响27-282.3 热塑性变形中的传热学28-302.3.1 传热的基本方式28-292.3.2 稳态传热和非稳态传热292.3.3 瞬态传热29-30第三章 淬火温度和保温时间对22MnB5机械性能的影响30-473.1 实验材料30-313.2 实验设备31-353.3 实验过程35-373.3.1 淬火温度对22MnB5硬度的影响353.3.2 保温时间对22MnB5机械性能的影响35-373.4 实验结果37-473.4.1 淬火温度对BG1.6、SG2.0硬度的影响37-383.4.2 保温时间对22MnB5机械性能的影响38-433.4.3 保温时间对淬火后TG2.0组织的影响433.4.4 沿22MnB5板料厚度方向上硬度的变化规律43-47第四章 不同冷却速率对22MnB5组织和机械性能的影响47-584.1 试验材料474.2 实验方案47-494.3 实验过程49-504.4 实验结果与分析50-584.4.1 不同距离、不同压力对板料将温速率的影响规律50-524.4.2 不同冷却速率对22MnB5机械性能的影响52-554.4.3 冷却速率对22MnB5微观组织的影响5