【作者】 张彩东；

【导师】 丁培道；

【作者基本信息】 重庆大学 ， 材料物理与化学， 2004， 硕士

【摘要】 薄带连铸技术被称为21世纪前沿连铸技术。它是由液态金属直接加工成金属薄带成品或半成品的一种新型加工工艺，与传统铸造工艺相比有着显著的优势，是扁平钢铁产品生产技术优化发展的方向，是钢铁企业实现优化生产流程的关键技术。本文分析了用实验室双辊薄带连铸机组生产出的高速钢快速凝固铸带组织特征，初步探索了后续高温热处理对铸带中共晶碳化物的影响规律，并进行了一系列的定量金相实验和透射电镜实验。实验结果表明：快速凝固技术有效地细化了高速钢铸带组织中共晶碳化物颗粒的尺寸，改善了组织中共晶碳化物的分布：后续热处理工艺不同程度地细化了高速钢铸带坯组织中共晶碳化物的尺寸，改善了高速钢铸带组织中共晶碳化物的分布情况，减少和细化了铸带组织中的网状碳化物，实验室机组生产的高速钢快速凝固铸带的最佳热处理制度是在1200℃下进行保温1h的后续热处理。为加速双辊薄带连铸高速钢快速凝固铸带的工业化生产进程，在前述实验工作的基础上对工业机组生产的高速钢快速凝固铸带进行了高温热处理和热加工变形实验，探索了高温热处理和热加工变形对工业机组铸带中共晶碳化物的影响情况，并比较分析了在相同的热处理和热加工制度下，二者先后工序不同对铸带中共晶碳化物的影响规律。定量金相实验和透射电镜实验结果表明：由于工业机组生产的铸带凝固速度较实验室条件下更快，铸带中的共晶碳化物颗粒和片层间距更加细小，在后续处理中更容易通过亚稳相的分解来使铸带中的共晶碳化物变得细小、弥散和均匀；比较不同的热处理制度和热加工制度及其工序对铸带组织的影响可以得出，先将铸带加热至1200℃保温40min后再进行50％加工变形量的处理工艺较为合理，它可以使铸带中的亚稳相较大程度的分解，并可以通过后续的热加工变形使铸带中的碳化物得以进一步的破碎，该处理条件下的铸带组织最佳。本文最后综合两种不同机组下热处理及热加工工艺对铸带组织中亚稳相分解的影响情况，研究了在快速凝固条件下亚稳相的形成、分解情况，提出了防止由于保温时间过长导致碳化物异常长大的措施。更多还原

【Abstract】 The twin-roll cast strip technology was considered as the newest one in the 21st century. It could change the melt metal into semi-finished or finished products directly, and had the obvious advantages in comparison with the traditional one. It was the trend of the thin steel production and the key technology to make the iron and steel enterprises modernized.The microstructure of the high speed steel (HSS for short) produced by the twin-roll caster with rapid solidification in lab was analysized. The laws that the effects aroused from the different heat-treatment were explored. The experiments of quantitative analysis and TEM showed that rapid solidification could refine the eutectic carbides in HSS, improve the distribution of the eutectic carbides. Heat-treatment could refine the carbides in HSS as-cast strip and improve the distribution of the eutectic carbides various degrees, and eliminate the eutectic carbides nets in HSS. At last the conclusion that the rational heat-treatment of HSS as-cast strip in lab was at 1200C, held time lh, was obtained.To speed up the course of industrialization of HSS in twin-roll cast strip technology, the heat-treatment and heat-deformation experiments were adopted based on the former work. The effects of heat-treatment and heat-deformation on the eutectic carbides in HSS as-cast strip in industrialization were studied. The experiments of quantitative analysis and TEM showed that the faster cooling rate was, the finer the carbides grain and space between two carbides were. The finer carbides decomposed more easily. Comparing the effects of the different heat-treatment and heat-deformation on the carbides showed the rational treatment of HSS as-cast strip in industrialization was at 1200C, held time 40min before carrying amount for 50% reduction heat-deformation. It could make the carbides decomposed greatly in heat-treatment and realize the carbides decomposed further in heat-deformation, get the best microstructure in as-cast strip.At last the effects of the treatment on the carbides in two different stages and studied the forming of metastable carbides in rapid solidification and its decomposing in heat-treatment were combined. The measures to prevent the new carbides fromabnormally growing up and spheroidizing were put forward.更多还原