低焊接裂纹敏感性钢回火组织及力学性能研究  

Tempering structure evolution and mechanical properties of a low welding crack susceptibility steel

作　　者：兰亮云[1] 邱春林[1] 赵德文[1] 高秀华[1] 杜林秀[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110819

出　　处：《材料科学与工艺》2011年第2期42-46,共5页Materials Science and Technology

基　　金：国家自然科学基金资助项目(50474015);中央高校基本科研业务费资助项目(N100607001)

摘　　要：为优化高强度低焊接裂纹敏感性钢的力学性能,对其热轧态钢板进行了不同温度的回火实验.通过光学显微镜、扫描电镜和透射电镜观察了回火显微组织的演变特征,并结合相应的力学性能检测手段分析了不同回火温度下显微组织与力学性能的关系.结果表明,550℃回火后屈服强度和抗拉强度较热轧态强度分别提高了115和30 MPa,平均冲击功提高了30 J.此回火温度下的组织维持了热轧态的晶界强化和位错强化效果,同时,弥散细小析出相分布在位错线上产生的析出强化效果成为提高回火强度的重要原因.650℃回火后组织中出现新相马氏体沿原始奥氏体晶界和退化板条贝氏体晶界断续分布,导致冲击韧性明显下降.To optimize the mechanical properties of a high strength low welding crack susceptibility steel, different temperature tempering tests were carried out on the hot-rolled steel plates in this study. Optical microscopy, scanning electron microscopy and transmission electron microscopy were employed to observe tempering microstructure evolution, and the relationship of tempering microstructures and corresponding mechanical properties was analyzed according to the results of mechanical properties tests. The results shows that the yield strength and tensile strength of 550℃ tempered specimens are increased by 115 MPa and 30 MPa, and the average impact absorbed energy is enhanced by 30 J compared with that of the hot rolled specimens. Microstructure analyses present that the specimens maintain relatively good boundary strengthening and dislocation strengthening effects. Meanwhile, that quite a number of fine precipitates disperse on dislocation lines is also an important factor to improve the strength. However, under the condition of 650℃ tempering, a new kind of martensite phase occurs along the boundary of prior austenite and degenerated boundary of lath bainite, and results in deterioration of toughness.

关 键 词：低焊接裂纹敏感性钢 回火组织 板条贝氏体 位错 

分 类 号：TG142[一般工业技术—材料科学与工程] TG156[金属学及工艺—金属材料]