【摘要】 首先基于响应曲面设计了单道次热丝熔覆试验,选取激光功率、扫描速度、送丝速度和熔覆电流作为变化因子,定义了体积缺陷率,与熔覆层宽度、高度共同作为目标响应,分析了单因子和多因子交互作用对响应的影响规律,建立了反映单道次熔覆工艺参数和成形质量关系的回归模型和经验公式。当选择较大的激光功率和送丝速度,适中的扫描速度和熔覆电流作为工艺参数组合时,激光热丝熔覆单道次成形质量最佳。其次建立多道次熔覆的搭接率模型,准确确定了搭接率参数,提高激光热丝多道次熔覆的成形质量。最后根据多道次熔覆截面微观组织的表征,可以看到在最佳工艺参数下,熔覆层与基体结合良好,金相组织均匀,无杂质气孔以及未熔合缺陷,验证了本文通过响应曲面法建立的工艺参数与响应变量之间关系模型和多道次熔覆搭接率模型的准确性。更多还原

【Abstract】 Response surface methodology( RSM) was used to optimize processing parameters of single-pass cladding. Laser power P,scanning speed Vs,wire feed rate Vfand cladding current I were selected as the input variables,while volumetric defect ratio,height of cladding and width of cladding value as the responses. The influence of the single factor and multiple factors interaction on the response was analyzed. Also,the regression model and the empirical formula in terms of the relationship between processing parameters and forming quality were established. The good forming quality of single-pass layer results from the larger P and Vfand moderate Vsand I. The mathematic model of cladding layer overlapping rate was set up to improve the forming quality of multi-pass layer. Finally,good metallurgical bonding was achieved in the interface between cladding layer and substrate,and uniform microstructure was observed based on the optimized process parameters. No blowhole,crack and incomplete fusion were found. It certified the accuracy of the relationship between process parameter and response variable based on response surface methodology( RSM) and the overlapping rate mathematic model in multi-pass layer.更多还原