960 MPa高强度钢材及其焊缝低温冲击韧性试验研究  

Experimental Study on Impact Toughness of 960 MPa High-Strength Steel and Its Butt Weld at Low Temperature

作　　者：王元清[1,2] 刘希月[1,2] 石永久[1,2] 

机构地区：[1]清华大学土木工程安全与耐久教育部重点实验室,北京100084 [2]清华大学土木工程系,北京100084

出　　处：《建筑材料学报》2014年第5期915-919,共5页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51178244)

摘　　要：对14mm厚的960MPa高强度钢材及其对接焊缝进行了低温冲击韧性试验研究,得到了母材、焊缝区和热影响区(HAZ)的夏比冲击功Akv随温度的变化关系及韧脆转变温度,将该结果与460MPa钢材及345MPa钢厚板进行比较分析,最后通过扫描电镜对其断裂微观机理进行了分析.结果表明:Akv随温度降低而下降,韧脆转变特征明显;960 MPa高强度钢材的Akv总体上大于460MPa钢材;与345MPa钢厚板相比,常温下高强度钢材的Akv较小,但随温度降低,普通强度钢厚板的Akv下降幅度更大;钢材强度过高使其吸收的弹性功较高,低温下厚度对其冲击韧性的影响较强度更明显,母材的低温Akv小于焊缝区,但焊缝区更容易发生韧脆转变,体现了960MPa高强度焊接钢材较大的缺陷敏感性.试验为960MPa高强度钢材及其焊接钢材在低温地区的推广应用提供了参考数据,同时也为研究冲击韧性和断裂韧性2个指标之间的关系提供了依据.A series of Charpy impact tests on 14 mm thick 960 MPa high-strength steel and its butt weld at low temperature were conducted,the relationship of Charpy impact energy Akv and temperature was studied and the test data were fitted by the Boltzmann function.Moreover,the test results of 960 MPa steel were compared with that of 460 MPa steel and 345 MPa steel thick plate,and the micro mechanism of fracture was analyzed through electron microscope scanning.The test results show that as temperature decreases,the variation of impact energy exhibits distinct ductile brittle feature; the Akvvalues for 960 MPa steel are higher than that for 460 MPa,which is resulted from the higher elastic deformation energy due to the high strength; and the Akvvalues for 460 MPa and 960 MPa high-strength steel are lower than that for 345 MPa steel thick plate at ambient temperature,while as temperature decreases,the decline amplitudes for 345 MPa steel thick plate are larger than those of the other two high-strength steel,showing the obvious effect of plate thickness on the impact toughness at low temperature; the impact toughness of base metal is lower than weld metal at low temperature,while the weld metal is more critical to brittle fracture.Rich experimental data were obtained for the impact toughness of 960 MPa steel and its butt weld in the study so as to provide reference for the application of 960 MPa steel and welded steel in cold regions and provide basis for the study on the correlation of impact toughness and fracture toughness.

关 键 词：高强度钢材 对接焊缝 低温 冲击韧性 韧脆转变温度 

分 类 号：TU391[建筑科学—结构工程]