摘要
采用奥氏体逆相变(ART)退火热处理工艺,研究了退火过程中碳化物析出行为对中锰钢中组织的演变、残余奥氏体含量及力学性能的影响。结果表明,实验钢经ART工艺处理后,获得了铁素体、残余奥氏体与少量马氏体多相组织;退火初期(5 min),碳化物受高密度位错钉扎C、Mn原子的抑制作用,使得逆相奥氏体先于碳化物在原奥氏体边界或马氏体板条界面析出;退火中期(10 min),位错密度因回复快速减小,C、Mn原子扩散激活能增大,促进了大量碳化物析出;随退火时间延长(30~60 min),细小碳化物作为新生奥氏体核心逐渐溶解,残余奥氏体体积分数以及残余奥氏体中C含量提高;伴随碳化物析出与溶解,实验钢屈服强度呈先升高后降低的趋势,而断后伸长率及均匀延伸率呈持续升高趋势,退火60 min时,断后伸长率达到41.1%,均匀延伸率达到34.3%,抗拉强度达到821 MPa,实验钢获得高达33 743 MPa·%的强塑积。
The effect of carbide precipitation behavior at different annealing time on microstructure evolution,retained austenite content and mechanical properties for medium manganese steel was investigated by means of ART(Austenite reversed transformation)annealing heat treatment process.The results indicate that the microstructure of experimental steel is composed of ferrite,retained austenite and a small amount of martensite heterogeneous structure after treated by ART process.In the pre-annealing(5 min),the carbide is inhibited by high-density dislocations pinning C and Mn atoms,so that reversed austenite is precipitated before carbides at the boundaries of prior austenite or martensite laths.In the middle of annealing(10 min),the dislocation density decreases rapidly due to recovery,and the diffusion activation energy of C and Mn atoms are increased,which promotes the precipitation of a large amount of carbides.With the annealing time prolonged(30-60 min),the fine carbides are gradually dissolved as the nascent austenite core,and the volume fraction of retained austenite and C content increase.With the precipitation and dissolution of carbides,the yield strength of experimental steel first increase and then decrease,but the elongation and uniform ductility after fracture show a tendency of continuous increased.After 60 min annealing,the elongation after fracture reaches 41.1%,the uniform ductility reaches 34.3%,and the tensile strength reaches 821 MPa.The experimental steel obtaines the production of strength and elongation of up to 33 743 MPa·%.
作者
田亚强
黎旺
郑小平
宋进英
魏英立
陈连生
TIAN Yaqiang;LI Wang;ZHENG Xiaoping;SONG Jinying;WEI Yingli;CHEN Liansheng(Key Laboratory of the Ministry of Education for Modern Metallurgy Technology,North China University of Science and Technology,Tangshan 063210)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第16期2765-2770,共6页
Materials Reports
基金
国家自然科学基金(51574107)
河北省自然科学基金(E2016209048
E2017209048)~~
关键词
中锰钢
碳化物析出行为
残余奥氏体
析出强化
加工硬化速率
medium-manganese steel
carbide precipitation behavior
retained austenite
precipitation strengthening
work hardening rate
