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采用Nd∶YAG脉冲激光对某发动机箱体主轴承座所用材料加工裂解槽。试验结果表明,激光热影响区组织得到细化,熔化区生成了细小的树枝状初晶和莱氏体,相变硬化区获得了隐针马氏体和残余奥氏体。X射线衍射(XRD)分析表明,熔化区碳浓度大于相变硬化区;裂解槽附近区域显微硬度均高于母材,硬化效果明显,熔化区显微硬度比相变硬化区高约260 HV;裂解槽硬化层随激光脉冲功率和脉冲宽度的增加而增大,随激光扫描速度的增加而减小,硬化层深度在0.232～0.625 mm之间;激光加工裂解槽为直缺口,灰铸铁的启裂和断裂效应明显。总结出激光功率、脉宽和加工速度等参数对裂解槽几何形貌的影响规律,并对工艺参数的选择提出了建议。
Nd: YAG pulsed laser is used to crack the groove in the material used for the main housing of the engine box. The experimental results show that the laser heat-affected zone structure is refined, fine dendrites and ledeburites are formed in the melt zone, and hidden-pin martensite and retained austenite are obtained in the phase-change hardening zone. X-ray diffraction (XRD) analysis shows that the carbon concentration in the melting zone is larger than that in the phase transition zone. The microhardness in the vicinity of the cracking tank is higher than that in the base metal. The hardening effect is obvious. The microhardness of the melting zone is about 260 HV ; Crack layer hardening layer with the laser pulse power and pulse width increases, with the increase of laser scanning speed decreases, the depth of the hardened layer between 0.232 ~ 0.625 mm; laser processing cracked groove is a straight notch, gray cast iron Cracking and fracture effects are obvious. The effects of laser power, pulse width and processing speed on the geometry of cracked cell are summarized. Some suggestions are put forward for the selection of process parameters.