Reheating Furnace Analysis and Optimization for Hot Stamping Automotive Parts

烫金是加拿大汽车制造能力中越来越重要的一部分。在此过程中，高 被称为“毛坯”的硼钢薄板被加热到大约950摄氏度，并在该温度下保持长达5分钟，以 形成奥氏体相。毛坯通常被浸渍一层铝硅层，该层与钢材熔合在 炉膛，提供短期防垢保护和长期耐腐蚀性。然后将热毛坯 转移到模具中，在模具中同时冲压成形和淬火，从而形成均匀的马氏体 部分具有很高的硬度和屈服强度。热冲压生产的汽车零部件具有优越的撞击性 与其他制造技术相比，使用更少的材料和更短的时间即可实现性能，大大降低了 制造成本，以及生产更安全、更轻、更省油的汽车。 最近在烫印方面的创新主要集中在改进模具技术上，但对毛坯的控制很高 加热也是获得碰撞性能所需的均匀硬度和抗拉强度所必需的，以及 为后续装配保持零件可焊性所需的保护层厚度。不均匀供热 导致有缺陷的零件，必须通过昂贵的工艺(如激光切割)进行纠正，或者只需 被丢弃了。 建议的研究重点是建立辊底式间歇加热炉和低型间歇式加热炉的传热模型。 目前由加拿大首屈一指的一级汽车零部件供应商Cosma International使用。然后将使用这些模型 用于炉膛运行参数的设计优化和在线控制，从而提高工艺效率 (部件/分钟)和部件质量。热传递模型还将允许Cosma修改炉子参数以 考虑到工艺变量、毛坯几何形状和毛坯材料的变化。这反过来将提供更大的 工艺灵活性和显著提高的生产率。最后，从长远来看，热传递模型将指导 科斯马收购和开发新的供暖技术。

Hot stamping is an increasingly important part of Canada's automotive manufacturing capacity. In this procedure, high boron steel sheets, called "blanks", are heated to approximately 950C and held at that temperature for up to 5 minutes to form austenite. The blanks are usually dip-coated with an aluminum-silicon layer that fuses to the steel within the furnace, providing short-term protection against scaling and long term corrosion-resistance. The hot blank is then transferred to a die in which it is simultaneously stamped into shape and quenched, thereby forming a uniformlymartensitic part of very high hardness and yield strength. Hot stamping produces automotive parts having superior crash performance with less material and in less time compared to other fabrication techniques, dramatically reducing manufacturing costs, and producing safer, as well as lighter, more fuel-efficient cars. Recent innovations in hot stamping have focused mainly on improving die technology, but highly-controlled blank heating is also essential to achieve the homogeneous hardness and tensile strength needed for crash performance, and the desired protective coating thickness to preserve part weldability for subsequent assembly. Inhomogeneous heating results in defective parts, which must either be corrected through expensive processes like laser-cutting or are simply discarded. The proposed research is focused on developing heat transfer models of roller hearth and low-profile batch furnaces presently used by Cosma International, Canada's premier Tier 1 automotive parts supplier. The models will then be used for design optimization and online control of the furnace operating parameters, thereby improving process efficiency (parts per minute) and part quality. The heat transfer models will also permit Cosma to modify the furnace parameter to account for changes to process variables, blank geometries and blank materials. This, in turn, will provide greater process flexibility and significantly improve productivity. Finally, in the longer term, the heat transfer models will guide Cosma's acquisition and development of new heating technologies.