激光直接制造镍基高温合金零件成形工艺的研究

The study of parameters for Laser Direct Manufacturing Ni based super-alloy

本文研究了激光直接制造镍基高温合金FHG95的工艺。通过不同的参数搭配共进行 314个试样的实验 ,按照一定标准 (宽度波动小于 5 %,单层熔覆厚度大于 0 .2mm ,表面没有粉末黏着 )选取成形效果较好的试样 ,分析总结了选择优化工艺参数的规律。分析了功率密度、送粉速度、扫描速度单独作用的机理和相互配比的方式 ,提出了送粉量承载率的概念 ,同时给出如何针对不同的熔覆层宽度、厚度选取工艺参数的方法。按照该工艺方法激光直接成形的镍基高温合金零件晶粒细小、组织致密 ,而且各元素含量与粉末相同 ,没有偏析。当熔覆基体尺寸为 2 0 0× 15 0× 2 5mm的低碳钢板时 ,激光功率密度应该在15 0 - 2 0 0W /mm2 ,扫描速度在 0 .2 - 0 .3m/min ,每瓦激光所能承担熔覆的合金粉末为 0 .0 2 g/min。当加工薄壁零件时 ,熔覆速度应大于 0 .5m/min ,单层熔覆厚度约为 0 .1mm。

In this article, the technics for laser direct manufacturing FHG95 super alloy has been studied. A serial of systematical experiments which produced totally 314 samples was made by different combination of parameters around a given rang. According to a standard (undulation of the width of the sample should be within 5%, each layer should be thicker than 0.2mm, no powder adhere to the surface), fine samples have been selected to analyze the infection of every parameter on producing result and the relationship between each one. And a method to select all these parameters has also been given. Powder density should be 150-200 W/mm2, powder burden rate is 0.02g/min. The microstructure is fine.