Application of polymeric quenchant in heat treatment of crack-sensitive steel mechanical parts: Modeling and experiments

Success or failure of a quenching process is determined by selecting an appropriate quenchant. In this work, the quenching process of the automobile tie rods in different media including water, oil, and a polymeric solution was investigated. The microstructures and mechanical properties of the rods were predicted by a finite element simulation model. Several specimens were cut from the tie rods and heat treated by quenching in five different quenching media including water, oil, and PAG aqueous solutions with polymer concentrations of 10, 20, and 30%. The hardness tests and metallographic analyses were performed on the specimens. Considering the results of the simulations and the experiments, the optimum quenchant was selected and the tie rods were heat treated using this quenchant. The results showed that the use of Poly Alkylene Glycol (PAG) solution quenchants, with respect to its unique cooling mechanism, outperformed water and oil quenchants. The distortion and cracking was reduced compared to water quenching and, on the other hand, the mechanical properties which were not achievable by oil quenching were resulted using polymer-based quenching medium.

Research highlights
► Quenching process of the automobile tie rods in water, oil, and polymeric solution was investigated.
► The optimum quenching medium was selected using modeling and experiments.
► The results showed that PAG, due to its unique cooling mechanism, outperformed water and oil quenchants.
► The developed numerical model efficiently predicted the resultant microstructure and hardness.
► The distortion and cracking were reduced and good mechanical properties were achieved using polymeric quenchant.