Effects of Temperature Variation on the Cutting Edge Hardness of Selected HSS and HCS Single Point Cutting Tools

B. Kareem, S.F. Daramola

Cutting tool life depends on the degree of resistance to wear on the cutting edge. Temperature rise due to heat generated in work piece and cutting tool interface was found to be responsible for tool wear. Dry cutting is necessary to prevent corrosive effect of coolants. On this basis, Rockwell class ‘A’ (HRA) hardness test was employed in testing the hardness of four selected single point cutting tools at varying temperature. The tools are High Speed Steel (HSS) tools (M4 and M1), and High Carbon Steel (HCS) tools (Q275 and A36) according to Society of American Engineers (SAE) steel grades. The temperature variation was achieved by heating the samples in a digital electric furnace at varying temperature from 150 ^oC to 750 ^oC as specified by the SAE standard, in step of 50^oC. The hardness number was read directly through a digital display unit of the Identec hardness tester, while determining the hardness of the cutting edge (tip) of the tool. The results obtained were analyzed using statistical regression model. From the experimental results, the high speed steel tools showed better hardness at higher temperatures than High carbon steel tools.  The range of temperature that supported dry cutting was predicted.