Surface Integrity in Hard Machining of 300 M Steel: Effect of Cutting-edge Geometry on Machining Induced Residual Stresses

300 M steel is widely used in the aerospace industry to manufacture landing gears due to its ultrahigh strength and high fracture toughness. Surface integrity in the hard turning process (one of the final manufacturing processes in making landing gears) can be influenced by tool geometries and cutting conditions. An experimental study is conducted on 300 M steel to understand the role of cutting tool geometry and cutting conditions on surface integrity (surface roughness and residual stresses). Cutting tool geometries are varied along the nose edge region (chamfer, hone, and chamfer-hone). These varied geometries are tested at different cutting conditions to highlight the combinational complexity of cutting edges and cutting conditions in producing surface roughness and residual stresses. The results show the necessity of edge preparation in improving machining surface integrity in such a material.