| During machining processes,continuous chip will decrease surface quality ofworkpiece,reduce tool life,and endanger the safety of operators.In this paper,laser cladded technology is used to fabricate a convex-shaped chip breaker with no cracks and porosity defects on the rake face of high speed steel turning tool.Fabrication processes and methods are studied.First,the cutting tests of LY12 hard aluminum alloy shows that thechip breaking effect ofhigh speed steel turning tool with laser cladded chip breaker is better than normal high speed steel turning tool,itcan obtain high processing surface quality.But the cladded chip breaker has cracks,bubbles and other defects.By factorial design of experiment,influence of process parameters on cladded crack defects was analyzed,and regression equation between crack rate and process parameters was establish.The results show that influence ranking of cladding process parameters on cladding crack is current,pulse width,frequency,scanning speed anddefocusing amount.Moreover,cladding cracks are affected by interactionbetween process parameters.Then,through the laser cladding experiment of several cladding powders,the cladding powder material suitable for W6Mo5Cr4V2 tool was determined by using M2 powder mixed with 15% WC-12 Co powder.The microhardness of the chip breaker is higher,the section of chip breaker has no cracks,bubbles and other defects,the reasons of crack elimination are explained by means of thermal expansion coefficient,XRD phase,hardness analysis and microstructure analysis.Finally,the influence of laser process parameters on the geometrical dimensions of cladding convex hull is studied by single factor test method.Then,the laser process parameters of cladding convex hull are optimized by orthogonal test.Finally,the influence of laser process parameters on the geometrical dimensions of cladding convex hull is studied by single factor test method.Then,the laser process parameters of cladding convex hull are optimized by orthogonal test. |
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