Experimental Investigation on the Effects of Various Quenchants on Hardened High Carbon Steels during Lathe Machining

The choice of quenchants during heat treatment of carbon steels can influence the properties of the steel sample. A knowledge of the effect of various quenchants on steel can therefore not be over emphasized. This paper presents results from the experimental investigation on the effects of using brine, water and palm-oil as quenchants during hardening of high carbon steels. Three samples of AISI 1090 high carbon steel (0.95%wt, Carbon) were furnace-heated at a temperature of 900oC in a crucible furnace and quenched using brine, water and oil to harden the steel samples. The hardened steel was machined using a pre-developed design of experiment (DOE). Process parameters during machining were Speed (50-150 rpm), Feed rate (0.3-0.9 mm/min), Depth of Cut (0.1-0.3mm) and Quenchant (water, brine and palm-oil). The responses analysed were surface roughness and tool wear rate. Results show that palm-oil with a lowest surface roughness and hardness (0.09μm and 150HB, respectively) and highest material removal rate (0.5124mm3/sec) was a preferred quenchant as it reduced surface roughness and increased material removal rate (MRR). Hence, Palm oil has proven to be a preferred quenchant during heat treatment of AISI 1090 steel for improved machinability and surface finish.