高热强性特种钢压扭成形细晶强化工艺  

Compression-torsion forming and fine-grain strengthening process for high-temperature and high-strength special steel

作　　者：刘科虹 张瑞锋 葛东伟 王莹莹 刘晓蓉 Liu Kehong;Zhang Ruifeng;Ge Dongwei;Wang Yingying;Liu Xiaorong(Inner Mongolia North Heavy Industries Group Corp.Ltd.,Baotou 014030,China)

机构地区：[1]内蒙古北方重工业集团有限公司,内蒙古自治区包头014030

出　　处：《锻压技术》2025年第3期212-219,共8页Forging & Stamping Technology

基　　金：国防基础科研计划(JCKY2022208A002)。

摘　　要：针对高热强性特种钢出现的屈服强度和冲击功偏低的问题,分析发现晶粒尺寸过大和大尺寸富铌相聚集分布等微观组织结构导致的材料的局部应力集中是主要原因。通过系统的微观组织表征阐明了材料的晶粒粗化机制与动态再结晶行为。基于压缩-扭转复合变形的协同剪切效应理论,在单轴变形体系中引入多向剪切应力场,成功构建了促进动态再结晶的应变路径。通过优化压扭成形工艺参数与热处理制度,开发出细晶强化新工艺。实验结果表明:压扭大变形工艺可同步实现晶粒超细化(晶粒度为6.0级)与富铌相均匀弥散分布,使材料屈服强度提升至941 MPa,冲击功达到27.6 J。For the problems of lower yield strength and impact energy in high-temperature and high-strength special steel,it was found that the main cause was the local stress concentration in the material,which was caused by the microstructures such as gains with overly large sizes and aggregated distribution of large-sized Nb-rich phase.Through systematic microstructural characterization,the grain coarsening mechanisms and the dynamic recrystallization behavior were elucidated.Based the synergistic shear effect theory of compressiontorsion composite deformation,a multi-directional shear stress field was introduced in uniaxial deformation system,establishing an strain path conducive to dynamic recrystallization successfully.A novel fine-grain strengthening process was developed through optimization of compression-torsion forming process parameters and heat treatment system.Experimental results demonstrate that the compressiontorsion process with severe deformation can achieve the simultaneous grain ultra-refinement(grain size is Grade 6.0)and the homogeneous dispersion of Nb-rich phases,resulting in enhanced mechanical properties with the yield strength of 941 MPa and the impact energy of 27.6 J.

关 键 词：压扭成形 动态再结晶 富铌相 晶粒细化 局部应力集中 

分 类 号：TG316[金属学及工艺—金属压力加工]