高强耐候钢焊接热影响区组织演变  

MICROSTRUCTURE EVOLUTION OF WELDING HEAT-AFFECTED ZONE OF HIGH-STRENGTH WEATHERING STEEL

作　　者：宋丽英 张志新 高秀华[1] 邢俊芳 薛启河 吴红艳[1] 杜林秀[1] Song Liying;Zhang Zhixin;Gao Xiuhua;Xing Junfang;Xue Qihe;Wu Hongyan;Du Linxiu(State Key Laboratory of Rolling Technology and Continuous Rolling Automation,Northeastern University,Shenyang 110819,Liaoning;HBIS Group Material Technology Research Institute,Shijiazhuang 050023,Hebei;Chengde Vanadium and Titanium New Materials Co.,Ltd.,Chengde 067102,Hebei)

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 [2]河钢材料技术研究院,河北石家庄050023 [3]承德钒钛新材料有限公司,河北承德067102

出　　处：《河北冶金》2023年第2期1-9,共9页Hebei Metallurgy

基　　金：国家重点研发计划项目(2022YFB3706402)。

摘　　要：利用热模拟试验机研究了Nb-Ti高强耐候钢在不同热输入条件下的热影响区组织演变和韧性变化,并采用热力学软件模拟计算了高强耐候钢的相变规律以及钢中第二相析出特征。结果表明,随着热输入量增加,焊接热影响区组织由板条贝氏体、针状铁素体向粒状贝氏体转变,且晶粒粗化程度增加;随着热输入量增加,焊接热模拟试样的低温冲击韧性逐渐降低,冲击断口中韧窝数量不断减少,在50 kJ/cm热输入条件下,冲击断口中存在大量的大尺寸解理面;高强耐候钢铁素体+奥氏体两相温度区间为684~830℃,钢中第二相主要以(Nb, Ti)(C,N)、NbN、TiN和Ti4C2S2形式存在,当温度高于1 200℃,钢中高熔点第二相为TiN和NbN。The microstructure evolution and toughness changes of Nb-Ti high-strength weathering steel under different heat input conditions were studied by thermal simulation testing machine, and the phase transition law of high-strength weathering steel and the second phase precipitation characteristics of steel were simulated by thermodynamic software. The results show that with the increase of heat input, the structure of the welding heat-affected zone changes from slatted bainite and needle ferrite to granular bainite, and the degree of grain coarsening increases. With the increase of heat input, the low-temperature impact toughness of welded thermal simulation specimens gradually decreased, the number of tenaments in the impact fracture continued to decrease, and under the heat input condition of 50 kJ/cm, there were many large-size cleavage surfaces in the impact fracture. The temperature range of high-strength weather-resistant steel prime + austenite two-phase is 684~830 ℃, the second phase in steel is mainly in the form of(Nb, Ti)(C,N), NbN, TiN and Ti4C2S2, when the temperature is higher than 1 200 ℃, the second phase with high melting point in steel is TiN and NbN.

关 键 词：高强耐候钢 焊接 微合金强化 显微组织 热输入量 相图 

分 类 号：TG406[金属学及工艺—焊接]