高强度合金钢中多元复合非金属夹杂的生成机理及塑性控制研究

High strength alloyed steel is one of the important steels in national economic constrction. Multiple composite non-metallic inclusions is the key factor which lend to reduce the fatigue life of the alloyed steel mechanical Component. In this project, thermodynamic calculation model is adopted, from which the equilibrium thermodynamics of the molten steel, slag and the inclusion are calculated, meantime four or five system composite non-metallic inclusions which are generated in low melting point zone in the high strength alloyed steel are discussed , and its influence factors are mastered. Simultaneously SEM—EDS、XRD and the inclusion that is extracted by the electrolytic in nonaqueous solution are adopted to comprehensive research the inclusion. In-situ observation of solidification process by CLSM is utilized to study the movement behavior and the transformation process of the inclusion. How the characteristics of the multiple composite non-metallic inclusions are influenced by slag-steel reaction are analyzed, in this way, the formation and plastification influence mechanism of the multiple composite non-metallic inclusions are illustrated, which will be the theoretical basis for realizing the plastification control of multiple composite non-metallic inclusions in high strength alloyed.

高强度合金钢是国民经济建设的重要钢材之一，多元复合非金属夹杂物是导致合金钢机械构件疲劳寿命降低的重要因素。本项目采用热力学计算模型，对钢液-炉渣-夹杂物的平衡热力学进行计算，探讨高强度合金钢中生成四元系及五元系低熔点复合非金属夹杂物的可能性，掌握获得不同体系低熔点复合夹杂物的影响因素；利用SEM—EDS、XRD衍射、非水溶液电解提取夹杂物等手段对钢中夹杂物特性进行综合研究；采用CLSM对凝固过程进行原位观察研究夹杂物运动行为及转变过程；通过分析渣—钢反应对钢中多元复合夹杂物特性的影响，阐明多元复合非金属夹杂物的生成机理与塑化的影响机制。项目研究成果最终能够为高强度合金钢中多元复合非金属夹杂物实现塑性控制提供一定的理论指导。

高强度合金钢是国民经济建设的重要钢材之一，它广泛应用于铁路、汽车、机械、军工、仪表等各个领域。目前具有重要意义的研究是提高钢材的使用寿命。高强度合金钢材质机械构件的失效因素中疲劳破坏约占90%以上，而非金属夹杂物经常成为机械构件疲劳破坏的起源。因此，为降低夹杂物对合金结构钢疲劳寿命的有害影响，必须对夹杂物进行无害化控制，这样钢材强度的大幅度提高才真正具有实际意义。本项目着重考虑高强度合金钢中多元复合非金属夹杂物的生成机理及塑性控制研究，从CaO-Al2O3-SiO2-MgO四元系及CaO-Al2O3-SiO2-MgO-MnO五元系复合非金属夹杂物生成特性及影响机制，钢液凝固过程中多元复合非金属夹杂物行为，渣—钢反应对钢中多元复合非金属夹杂物塑性转变影响规律三方面深入研究探讨。通过本项目的研究，揭示了高强度合金钢中多元符合非金属夹杂的生成与控制机理，实现了对四元、五元渣系下低熔点多元夹杂物生成的热力学条件的预测，典型高强度合金钢中多元复合非金属夹杂的二维/三维角度的全面认识，一定动力学条件下多元复合非金属夹杂被钢液凝固前沿推动—捕捉行为影响规律的探索，以及实际冶炼实验研究的验证。