焊接热输入对新型低Mn微Nb钢CGHAZ组织及冲击韧性的影响  

Effect of Welding Heat Input on Microstructure and Impact Toughness of CGHAZ in a Novel Low- Manganese Niobium- Microalloyed Steel

作　　者：何江里 王厚昕 周海 胡其龙 顾晓勇 王青峰[1] HE Jiangli;WANG Houxin;ZHOU Hai;HU Qilong;GU Xiaoyong;WANG Qingfeng(School of Materials Science and Engineering,Yanshan University,Qinhuangdao Hebei 066004,China;CITIC-CBMM Microalloying Technology Center,Beijing 100004,China;Titan Wind Energy(Suzhou)Co.,Ltd.,Suzhou Jiangsu 215400,China;Nanjing Iron&Steel Co.,Ltd.,Nanjing Jiangsu 210035,China;China Railway Shanhaiguan Bridge Group Co.,Ltd.,Qinhuangdao Hebei 066200,China)

机构地区：[1]燕山大学材料科学与工程学院,河北秦皇岛066004 [2]中信微合金化技术中心,北京100004 [3]天顺风能(苏州)股份有限公司,江苏苏州215400 [4]南京钢铁股份有限公司,江苏南京210035 [5]中铁山桥集团有限公司,河北秦皇岛066200

出　　处：《上海金属》2022年第5期6-12,共7页Shanghai Metals

基　　金：国家自然科学基金(51671165)。

摘　　要：借助Gleeble-3500热模拟试验机,结合光学显微镜、扫描电子显微镜、电子背散射衍射仪、透射电子显微镜、能谱仪、Thermo-Calc热力学计算及冲击性能测试等手段,研究了焊接热输入对一种新型低Mn微Nb钢粗晶热影响区(coarse grained heat affected zone, CGHAZ)组织和冲击韧性的影响。结果表明:随着焊接热输入的降低,CGHAZ中板条贝氏体(LB)数量增多,粒状贝氏体(GB)数量减少,γ→α相变开始温度A降低,组织显著细化;CGHAZ的-20℃冲击吸收能量(KV)随焊接热输入的降低而升高,冲击断口均呈现出典型的穿晶解理断裂特征,其解理面尺寸随焊接热输入的降低而减小;随着热输入的降低,细小弥散的Nb(C,N)粒子数量增多,平均尺寸减小。Effect of welding heat input on the microstructure and impact toughness of the coarse grained heat affected zone(CGHAZ) in a novel low manganese niobium-microalloyed steel was investigated using Gleeble-3500 thermal simulation tester in conjunction with the optical microscope, scanning electron microscope, electron backscatter diffractometer, transmission electron microscope, energy dispersive spectrometer, Thermo-Calc thermodynamic calculations and impact performance testing. The results showed that with the decrease in welding heat input, the amount of lath bainite(LB) increased and the amount of granular bainite(GB) decreased in CGHAZs, the starting temperature(A) for γ→α transformation reduced, and the microstructure was refined obviously. Besides, the impact absorbed energy(KV) at-20 ℃ of CGHAZs increased with the decrease in welding heat input, the impact fracture showed typical characteristics of transgranular cleavage fracture, and size of cleavage face decreased with the decrease in welding heat input. Finally, as the heat input decreased, the fine dispersed Nb(C,N) precipitates increased in number and decreased in average size.

关 键 词：低Mn微Nb钢 焊接热输入 粗晶热影响区 热模拟 冲击韧性 

分 类 号：TG142.1[一般工业技术—材料科学与工程]