GH4169叶片悬臂插磨表面完整性及参数优化研究

Study on Surface Integrity and Parameter Optimization of GH4169 Machined by Cantilever Plunge Grinding

利用超硬磨料砂轮进行GH4169叶片型面的精密磨削加工是提高其几何精度的有效手段。通过对GH4169材料进行悬臂插磨试验发现在精磨参数下磨削表面硬度在44~47HRC之间,叶片表面双方向均获得较大的残余压应力,进给方向上的残余压应力大于线速度方向上的残余压应力,且磨削参数对磨削表面硬度和残余压应力的影响不显著。在此基础上,基于磨削表面粗糙度小于Ra0.5μm的要求,提出叶片插磨的参数优化原则,为了降低磨削粗糙度推荐插磨参数：砂轮线速度26.8m/s,进给速度1000mm/min,型面磨削残高2μm;为了减小磨削力引起叶片的弹性变形所造成的加工误差,推荐磨削深度为0.005mm。在推荐参数下所加工叶片的形状精度可达到20μm以内,磨削表面以下没有明显的拉应力层,压应力层深度约为70μm,最大残余压应力位于表面下5μm处。以上研究为GH4169叶片的悬臂插磨工艺提供了一种基于表面完整性的参数优化方法和一组经过优化的精磨参数。

Grinding GH4169 blades by superhard abrasive wheel is effective for geometric accuracy improvement. The grinding experiment with finish parameters shows that the surface hardness is at 44~47HRC and the residual stresses in both directions are compressive and the value of the feed direction is larger. Both of the hardness and residual stresses is insensitive to parameters. According to this experiment results, the optimization principle and recommended parameters were proposed. On the demand of roughness, the grinding speed adopts 26.8m/s, the feed speed is 1000mm/min, the scallop height is 0.002 mm. On the order to decrease the elastic deformation caused by grinding force, the grinding depth adopts 0.005 mm. The grinding experiment with recommended parameters shows that the blade shape precision is within 20μm. The stresses layer depth is about 70μm while the largest stresses is at 5μm under grinding surface. And there is no significant tensile stress layer. This research provide a parameter optimization method based on surface integrity and a set of optimized grinding parameters for GH4169 blade cantilever grinding.