Mo-Ti微合化热轧高强钢的组织与性能  

Microstructure and mechanical properties of hot rolled Mo-Ti microalloyed high strength steel

作　　者：衣海龙[1] 龙雷周 刘振宇[1] 王国栋[1] 

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《材料热处理学报》2015年第12期145-151,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51104046);中央高校基本科研业务费资助(N120407001)

摘　　要：对一种Mo-Ti微合金钢进行了热轧实验,研究了不同工艺条件下的组织特征、析出行为及低温冲击性能。结果表明,随着终轧温度及终冷温度的降低,实验钢的屈服强度和抗拉强度均有所升高;当终轧温度较高时,细小的析出物主要在冷却及模拟卷取过程中产生,当终轧温度较低时,细小的析出物主要由应变诱导析出及冷却、模拟卷取过程的析出物组成;实验钢的组织以铁素体为主,随着终轧温度及终冷温度的降低,晶粒尺寸明显细化,同时,组织中渗碳体及钛的碳化物等岛状物的尺寸也变小,大角度晶界比例增加,低温冲击裂纹由脆性断裂变为韧性断裂;当终轧温度为800~810℃,终冷温度分别为615℃和500℃时,实验钢的屈服强度分别为738 MPa及768 MPa,抗拉强度分别为857 MPa和872 MPa,伸长率为18%~19%,其韧脆转变温度低于-70℃,实验钢具有良好的强度及韧性指标。The hot rolling trials were carried out for a Mo-Ti microalloyed steel,and microstructure characteristics,precipitation behavior and low temperature impact properties of the steel were investigated under different conditions. The results show that the yield and tensile strength of the steel increase with the decreasing of finishing rolling and coiling temperature. Fine precipitates are only obtained from cooling,simulation coiling process when finishing rolling temperature is high,but much more finer precipitate can be obtained from strain induced precipitation and cooling,simulation coiling process when finishing rolling temperature is low. The microstructure of the steel is mainly ferrite,and gain and carbide island size are decreased with the decreasing of finish rolling and coiling temperatures,and the proportion of large angle grain boundary increases also,so the low temperature impact crack change from brittle to ductile fracture. The yield strength of the steel can be 738 MPa and 768 MPa,and tensile strength of steel can be 857 MPa and 872 MPa,respectively,when the finish rolling temperature is 800-810 ℃ and coiling temperature is 615 ℃ and 500 ℃,respectively,and elongation for both process is18%-19%,and the ductile to brittle transition temperature is low than- 70 ℃,so the good strength and toughness are obtained for the tested steel.

关 键 词：Mo-Ti微合金钢 铁素体 析出物 韧脆转变温度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]