摘要
目的 以CHDG-B合金为研究对象,探究其焊接热影响区的微观组织、力学行为与加热速度的相互作用机制。方法 采用固溶处理后的CHDG-B试样,分别在100、50、10℃/s的加热速度下进行焊接热模拟实验。利用金相显微镜、扫描电镜和透射电镜对热影响区(HAZ)的微观结构进行详尽分析。此外,还进行了硬度、冲击、拉伸试验等性能测试。结果 随着加热速度的减小,与母材相比,CHDG-B合金的晶粒尺寸变化不明显,但析出相Nb C的形态由细小圆球状逐渐变为条带状。加热速度减小导致热影响区硬度下降,同时组织韧性降低。当加热速度大于10℃/s时,NbC析出相在晶界处的钉扎作用有效细化了晶粒,提升了热影响区的硬度,但当加热速度过低时,析出相的长大增加了微裂纹的形成趋势,进而影响了材料的韧性。冲击断口观察结果表明,CHDG-B合金的断裂机制为韧性断裂。结论 当加热速度大于10℃/s时,既保证了CHDG-B合金热影响区的硬度,又维持了良好的韧性,从而为实际应用中焊接工艺的制定提供了理论依据和技术指导。
The work aims to take CHDG-B alloy as the research object to explore the interaction mechanism of microstruc-ture,mechanical behavior,and heating rate of the welding heat affected zone(HAZ).Post-solution treated CHDG-B alloy specimens underwent welding thermal simulation experiments at varying heating rates of 100,50,and 10℃/s.Microstructural analysis of HAZ was conducted in detail using optical microscopy,scanning electron microscopy(SEM),and transmission elec-tron microscopy(TEM).Additionally,hardness tests,Charpy impact tests,and tensile tests were performed.The experimental findings revealed that,as the heating rate decreased,there was minimal noticeable change in grain size of CHDG-B alloy com-pared with the base metal;However,the morphology of the precipitated phase NbC evolved from fine spherical shapes to a more strip-like distribution.A reduction in heating rate lead to a decrease in HAZ hardness and a decline in toughness.When the heating rate was above 10℃/s,the pinning effect of NbC precipitates at the grain boundaries effectively refined the grain struc-ture,enhancing HAZ hardness.However,excessively low heating rates facilitated the growth of precipitates,increasing the pro-pensity for microcrack formation,which adversely affected material toughness.Charpy impact fracture observation confirmed that the fracture mechanism of CHDG-B alloy was ductile.Taking all factors into account,a heating rate greater than 10℃/s not only ensures adequate HAZ hardness but also maintains good toughness,thereby providing theoretical groundwork and tech-nical guidance for the formulation of welding procedures in practical applications.
作者
胡明磊
胡斌
徐科
张维
于祥龙
陈光
李冬升
HU Minglei;HU Bin;XU Ke;ZHANG Wei;YU Xianglong;CHEN Guang;LI Dongsheng(CNNC Nuclear Power Operation Management Co.,Ltd.,Zhejiang Haiyan 314300,China;School of Materials Science and Engineering,Jiangsu University,Jiangsu Zhenjiang 212013,China)
出处
《精密成形工程》
北大核心
2025年第8期222-228,共7页
Journal of Netshape Forming Engineering
基金
江苏省博士后科研资助计划(1601048C)。
