K418与42CrMo异种金属激光焊接接头组织与力学性能

Microstructure and mechanical properties of K418 and 42CrMo dissimilar metal laser welding

关键词:  激光焊接  热影响区  K418  42CrMo  组织

Key words:  laser welding  heat-affected zone  K418 nickel alloy  42CrMo steel  microstructure

摘要:

试验研究了额定功率为3kW的连续波Nd:YAG激光焊接热输入对激光焊接K418与42CrMo异种金属焊缝形貌的影响。通过光学显微镜、扫描电镜、能谱分析仪、硬度仪、万能试验机及X衍射对激光焊接K418与42CrMo异种金属焊缝接头组织、元素分布、相组成及接头的力学性能进行分析。结果表明,在焊接热输入恒定的条件下,高功率、高焊速的匙孔焊接比低功率、低焊速的热传导焊接更能增加焊缝熔深。通过扫描电镜在焊缝区域观察到了颗粒状物和针状物,能谱分析表明,颗粒状物Nb,Ti,Mo元素聚集,Fe,Ni元素减少;针状物Ti,Nb元素聚集。K418与42CrMo异种金属激光焊接工艺参数优化后的焊缝抗拉强度高于42CrMo母材。

Abstract:

The influences of welding heat input on weld of laser welding of K418 and 42CrMo dissimilar metal were experimentally investigated using continue wave Nd:YAG laser of output power 3 kW.Microstructure of the welded joint was studyed by optical microscope, scanning electron microscope, X-ray diffraction, and energy dispersive spectrometer.Mechanical properties of the weld were evaluated by hardness and tensile strength test.Results show that weld penetration of keyhole welding mode is larger than of heat conduction welding mode with constant linear heat input.Particle of rich Nb, Ti and Mo and deleted Fe and Ni and needle of rich Nb and Ti are observed in the fusion zone.The tensile strength of weld is higher than that of base metal of 42CrMo by optimizing laser welding parameters.