LF25新型高氮奥氏体气阀钢热变形行为  

Hot deformation behavior of LF25 new high nitrogen austenitic valve steel

作　　者：任文浩 王立民[1] REN Wen-hao;WANG Li-min(Institute of Special Steels,Central Iron&Steel Research Institute,Beijing 100081,China)

机构地区：[1]钢铁研究总院特殊钢研究所,北京100081

出　　处：《塑性工程学报》2021年第12期125-131,共7页Journal of Plasticity Engineering

基　　金：国家重点研发计划(2017YFB0305203);国家自然科学基金资助项目(51971226)。

摘　　要：采用Gleeble-3800热模拟试验机在变形温度950~1200℃、变形速率0.1~10 s^(-1)范围内对LF25钢进行热模拟压缩试验,研究了材料的流变行为和组织变化。结果表明,氮原子的引入提高了材料的变形抗力,在1000℃、0.1 s^(-1)的变形条件下,与21-4N、316L和NCF3015相比,LF25钢的变形抗力分别提高了59、99和111 MPa;LF25钢的软化机制主要为动态再结晶,通过应变硬化曲线确定了动态再结晶的临界点;基于应变补偿的Arrhenius模型确定了LF25奥氏体钢的本构方程,LF25钢的热变形激活能Q为438.8 kJ·mol^(-1);LF25奥氏体钢的最优热加工区间为变形温度1080~1130℃,应变速率0.1~0.5 s^(-1),在变形温度为1100℃时,晶粒尺寸由原始的15~30μm降低至4~10μm。The hot simulation compression test of LF25 steel at deformation temperature of 950-1200 ℃ and strain rate of 0.1-10 s^(-1)was investigated using Gleeble-3800 thermal simulator. The rheological behavior and microstructure evolution were investigated. The results show that the introduction of nitrogen atoms improves the deformation resistance of material. Compared with 21-4 N, 316 L and NCF3015, the deformation resistance of LF25 steel increases by 59, 99 and 111 MPa, respectively, under the deformation conditions of 1000 ℃ and 0.1 s^(-1). The softening mechanism of LF25 steel is mainly dynamic recrystallization(DRX), and the critical point of DRX is determined by the strain hardening curve. Based on the Arrhenius model with strain compensation, the constitutive equation of LF25 austenitic steel is determined. The hot deformation activation energy Q of LF25 steel is 438.8 kJ·mol^(-1). The opimal hot processing range is the deformation temperature of 1080-1130 ℃ and the strain rate of 0.1-0.5 s^(-1). When the deformation temperature is 1100 ℃, the grain size decreases from the original 15-30 μm to 4-10 μm.

关 键 词：高氮奥氏体钢 动态再结晶 热加工图 

分 类 号：TG142.1[一般工业技术—材料科学与工程]