加压技术在高品质特殊钢冶炼和凝固中的作用

 加压技术在高品质特殊钢冶炼和凝固方面的研究主要集中在含氮不锈钢，尤其是高氮钢的冶炼制备技术；综述了加压技术在高品质特殊钢制备过程中的作用，如增大易挥发元素（氮、钙、镁等）溶解度及改善凝固组织等作用，并以高氮钢（22Cr-21Ni-7.5Mo-0.6N）为试验钢种，结合Thermo-Calc热力学计算软件探讨了压力对凝固相变过程的影响规律，计算结果表明，当加压至100 MPa后，固液相线温度分别提高了6.60和5.98 K，且改变了奥氏体形成区域大小，增加了固液相变驱动力，减小了临界形核半径，增大了形核速率。随着对易挥发元素作用认识的不断深入，加压技术将在高品质特殊钢的研发和制备过程中发挥至关重要的作用。

Effect of pressurization technology on steel-making and solidification of high-grade special steels

Presently， the study of pressurization technology in steel-making and solidification of high-grade special steels mainly focuses on the N-alloyed stainless steels， especially for high-nitrogen steels. This article reviewed the role of pressurization technology in steel-making and solidification， such as increasing the solubility of volatile elements (N， Ca， Mg， et al.) and improving solidification structure. In this article， experiments on N-alloyed stainless steel 22Cr-21Ni-7.5Mo-0.6N and thermodynamic computing software Thermo-Calc were combined to analyze the influence of pressure on liquid-solid phase transformation. It showed that the solidus and liquidus temperature were increased by 6.60 and 5.98 K under 100MPa compared with those under 0.1 MPa and austenite region was expanded. Pressurization also increased driving force of liquid-solid phase transformation， decreased critical nucleation radius， accelerated nucleation rate and further refined solidification structure. Along with the deepening understanding of the volatile elements， the application prospects of pressurization technology will be very broad and bright in the manufacture of high-grade special steels.