Suitability of linearalkylbenzene (Lab) and toluene as steel quenchants

Evaluation of toluene and linearalkylbenzene as quenching media for 0.49 and 1.14Wt%C carbon steel was investigated. The samples were quenched to room temperature in the quenching media (toluene, linear alkyl benzene and water). The machined specimen of the steel were heated at 8400C and 8800C then quenched in water, toluene and linear alkyl benzene. Tensile strength, hardness and impact energy were used to measure the quenching potentials of the various media. The microstructures and mechanical properties of the quenched samples were used to determine the quench severity of the petrochemical products. The test of the mechanical properties shows that the hardness of steel quenched in water was (50.0, 46.6 and 63.1, 64.2 HRC), while the hardness of steel quenched in toluene was (8.9, 17.0 and 40.4, 44.3 HRC) samples which was recorded as the least in all samples quenched. Samples quenched in toluene absorbed the highest amount of energy (57.4, 34.3 and 16.0, 12.5J) before fracture while samples quenched in water absorbs the least energy (13.7, 6.5 and 3.4, 2.7J). The microstructure of the samples quenched in the toluene under study revealed the formation of low proportions of martensite and in the case of linearalkylbenzene, there was retained austenite. Hence, linearalkylbenzene can be used where cooling severity less than that of water would be required for hardening of plain carbon steels.