钛微合金化高强钢基于新型TMCP技术的纳米相析出调控机制

Ti microalloyed high-strength steel is a new-type steel material with low-cost and high-performance, and its strength-controlling problem is one of significant and challenging issues in this field. With the progress of steelmaking technology, the fluctuation problem of components has been basically solved, while the mechanical performance fluctuation caused by nano-TiC precipitation which is subjected to TMCP process parameters is still outstanding. In this project, according to the above problem, a Ti microalloyed high-strength steel (0.05C-1.5Mn-0.10Ti wt.%) are studied, carried on a thermal simulator and a lab and industrial roller, respectively. By means of electron microscopy, chemical phase analysis, positron annihilation as well as strength increment calculation methods, precipitation behavior and properties of TiC nanoparticles based on a new type TMCP technology are to be explored, the relationship between stain-induced precipitation and inter-phase precipitation are to be determined. Also, the interactive mechanisms between nano-TiC precipitation and austenite recrystallization, phase transformation and cellular dislocation structure evolution, ect. are also to be revealed, such as to establish the metallurgical relationship of “process-precipitation-microstructure-strength”, on the basic of the new type TMCP technology. Therefore, the regulation mechanism of nanometer precipitates in Ti-microalloyed high-strength steel will be clarifiedd, which provides a theoretical basis and design ideas for solving the strength fluctuation problemand the stable production of low-cost and high-strength Timicroalloyed steel.

钛微合金化高强钢是一种低成本高性能的新型钢铁材料，其强度的稳定控制问题一直是该领域的一个重要且具有挑战性的课题。随着炼钢技术的进步，钢的成分波动问题已基本解决，而由于纳米相析出对TMCP工艺参数敏感所引起的性能波动问题仍十分突出。本课题拟将针对此问题，以单一钛微合金化高强钢为研究对象，结合热模拟试验和热轧试验，利用电子显微镜、化学相分析、正电子湮没等分析手段并协同强度增量计算方法，探明基于新型TMCP技术下纳米TiC的析出行为及特性，确定形变诱导析出与相间析出之间的内在作用关系，揭示纳米TiC析出与奥氏体再结晶、相变以及胞状位错结构演变等物理冶金行为的交互作用机制，进而建立适用于新型TMCP工艺特征的“工艺-析出-组织-强度”物理冶金学基础数据，阐明纳米相析出的稳定调控机制，为稳定生产低成本高强度的钛微合金钢提供设计思路和理论依据。

Ti微合金高强钢是一种低成本高性能的新型钢铁材料，其强度的稳定控制问题一直是该领域的一个重要且具有挑战性的课题。随着炼钢技术的进步，钢的成分波动问题已基本解决，而由于纳米相析出对TMCP工艺参数敏感所引起的性能波动问题仍十分突出。基于此，本项目设计出一种低碳钛微合金钢 (0.05C-1.5Mn-0.10Ti wt.%)，采用热模拟试验机并结合透射电子显微镜（TEM）、三维原子探针技术（APT）以及显微硬度仪等设备手段，探明了基于新型TMCP工艺下的纳米碳化物析出规律，揭示了纳米碳化物析出及其与奥氏体再结晶、相变和钢强化等物理冶金行为的交互作用机制，阐明了纳米析出相的规律和稳定调控机制，建立了“工艺-析出-强度”物理冶金学基础数据，为稳定生产低成本高强度的Ti微合金钢提供设计思路和理论依据。