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  • Study on surface integrity ...
    JIN, Qichao; CAO, Shuaishuai; WANG, Wenhu; JIANG, Ruisong; GUO, Lei

    Xibei Gongye Daxue Xuebao, 02/2022, Volume: 40, Issue: 1
    Journal Article

    In order to control the forming surface quality of signal crystal turbine blade tenon teeth in the creep feed grinding, the influence of the creep feed grinding parameters on the grinding surface integrity of DD5 nickel-based single crystal superalloy was investigated via orthogonal experiment. The results showed that the surface roughness along vertical grinding direction was ranged at 0.56-0.74 μm at the grinding wheel speed range of 15-30 m/s, feeding velocity range of 120-210 mm/min and grinding depth range of 0.1-0.7 mm, and the surface roughness in the grinding direction is about 1/5 of that in the vertical grinding direction. The surface topography and texture results showed that there were the obvious grooves and ridges on the grinding surface caused by the grain ploughing and scratching, the length and height of grooves and ridges on the grinding surface changed obviously under different processing parameters, and the three-dimensional topography of the grinding surface fluctuated obviously. The length of grooves and ridges along the grinding direction were sensitive to the speed of grinding wheel, waviness of grooves and ridges along the vertical grinding direction were sensitive to the grinding depth and workpiece feed rate. The different degrees of work hardening effect were presented at the grinding surface, the biggest work hardening effect achieved at 11.6%, and the maximum depth of work hardening effect was 110 μm. The distinct plastic deformation appeared at the grinding surface. The γ phase presented slip deformation along the grinding direction with various degrees, and the γ ' phase presented skewing, twisting, broken and fracture, the maximum depth of plastic deformation was 2.92 μm. The work hardening effect of DD5 creep feed grinding mainly due to the plastic deformation degree at the grinding surface. The experimental conclusions provided theoretical guidance for DD5 signal crystal turbine blade tenon teeth. 为控制单晶涡轮叶片榫齿缓进磨削成形表面质量, 通过实验研究缓进磨削工艺参数对DD5镍基单晶高温合金磨削表面完整性的影响规律。实验结果表明, 当砂轮线速度在15~30 m/s、工件进给速度在120~210 mm/min、磨削深度在0.1~0.7 mm参数范围内, 磨削表面垂直磨削方向粗糙度在0.56~0.74 μm范围内, 沿磨削方向粗糙度约为垂直磨削方向粗糙度的1/5。三维形貌和表面纹理测试结果表明磨削表面存在明显的因磨粒耕犁和划擦而产生的表面凹槽和材料隆起现象, 不同工艺参数下磨削表面凹槽和隆起材料的长度和高度有较明显变化; 砂轮线速度对沿磨削方向凹槽和隆起长度影响较敏感; 磨削深度和工件进给速度对垂直磨削方向的凹槽和隆起轮廓起伏程度敏感。磨削表面出现了不同程度加工硬化, 最高达11.6%, 最大硬化层深度达到110 μm; 磨削表面层出现明显塑性变形, γ 相沿着磨削方向出现不同程度的滑移变形, 立方化的 γ ' 相出现了偏移、扭曲、破碎断裂现象, 最大塑性变形层厚度为2.92 μm; DD5缓进磨削塑性变形是加工硬化产生主要原因。实验结果对DD5榫齿磨削提供理论指导。