Investigation of Influencing Factors on Surface Quality during Low-Speed Cutting of Steels with a Hardness exceeding 50 HRC for forging Dies

Abstract

This study investigates the factors that affect surface quality in low-speed milling of steel with a hardness greater than 50 HRC, specifically for forming molds. The material used in the experiment was SKT4 mold steel with a hardness of 50 HRC, which is commonly employed to form molds, with dimensions of 100×100×50 mm. The cutting tools put into service were carbide ball end mills of the HARD Series 5R×10×60L. This study examines changes in the surface roughness values of the milled workpiece material based on the feed rate and cutting depth. The constant spindle speed deployed was 1,200 rpm, and heat dissipation was achieved by air cooling. The results revealed that the feed rate and the interaction between the feed rate and the cutting depth had a p-value of 0.000. This considerably influences the average surface roughness (Ra) value at the 0.05 significance level. However, the cutting depth had a p-value of 0.061, which is greater than the significance level of 0.05 and thus does not substantially affect the average surface roughness.