铌钛微合金化铁素体-贝氏体双相管线钢再加热时奥氏体晶粒的长大行为  

Growth Behavior of Austenite Grain in Niobium and Titanium Microalloyed Ferrite-Bainite Dual Phase Pipeline Steels during Reheating

作　　者：谭峰亮[1] 贾书君[2] 张洪博[3] 汪力[1] 

机构地区：[1]湖南人文科技学院能源与机电工程系,娄底417000 [2]钢铁研究总院工程用钢研究所,北京100081 [3]中南大学材料科学与工程学院,长沙410083

出　　处：《机械工程材料》2016年第1期10-15,共6页Materials For Mechanical Engineering

基　　金：国家科技支撑计划项目(2011BAE35B01);湖南人文科技学院新进人才科研启动项目(8250147)

摘　　要：采用Thermo-calc热力学软件以及硬度仪、光学显微镜、扫描电镜、透射电镜等研究了铌钛微合金化铁素体-贝氏体双相管线钢在1 050~1 220℃再加热过程中奥氏体晶粒的长大行为以及铌的固溶行为对晶粒尺寸的影响。结果表明：在试验温度范围内,试验钢奥氏体晶粒的平均尺寸随再加热温度升高而增大;增加铌含量能有效抑制奥氏体晶粒长大,但当铌的质量分数增至0.080%时,奥氏体晶粒的大小和分布不均匀;再加热过程中钛在奥氏体中主要以沉淀相存在,铌在奥氏体中的固溶量随温度升高呈＂S＂形增加,未固溶铌含量是影响奥氏体晶粒尺寸的关键因素;试验钢中碳和钛的质量分数分别为0.065%和0.01%时,控制未固溶铌的质量分数高于0.005%即可将奥氏体晶粒尺寸有效控制在100μm以内。Growth behavior of austenite grains in niobium and titanium microalloyed ferrite-bainite dual phase pipeline steels during reheating of 1 050- 1 220 ℃ was studied by Thermo-calc thernodynamic software and hardness testing, optical microscopy, scanning electron microscopy and transmission electron microscopy, as well as the effect of niobium＇s dissolved behavior on grain size. The results show that average size of austenite grain increased with the increase of reheating temperature at the range of tested temperature. The growth of austenite grain could be restrained by increasing niobium content, but the size and distributin of austenite grain were unevenly when mass fraction of niobium up to 0.080%. Titanium was mainly in the form of precipitation phase in austenite during reheating, the relationship between dissolved of niobium in austenite and reheating temperature exhibited ＂S＂ shape curves, the amount of undissolved niobium was the key factor to influence austenite grain size. When mass fraction of carbon and titanium in tested steel were 0.065% and 0.010% , respectively, the average size of austenite grain could be controlled within 100μm effectively if the mass fraction of undissolved niobium exceed 0.005%.

关 键 词：铁素体-贝氏体双相管线钢 铌 奥氏体晶粒 

分 类 号：TG142.41[一般工业技术—材料科学与工程]