Deep Cryogenic treatment has had a dramatic effect on the development of wear resistance of steel components. It is a supplement process to the conventional heat treatment process of steels. The aim of the present research work is to optimize the parameters affecting the deep cryogenic treatment process for attaining the minimum wear loss of 4140 steel. The selected process parameters for this optimization study are hardening temperature (A), soaking period (B), tempering temperature(C) and tempering period (D). The optimum levels and the interaction of the deep cryogenic treatment parameters for 4140steel are arrived using L27 Taguchi orthogonal design. The experimental result shows that hardening temperature is the most significant factor in the deep cryogenic treatment process. Moreover, ANOVA analysis shows that the percentage contribution of hardening temperature is 17.34% when compared with the other factors.
Keywords: (A) ferrous metals and alloys, (E) wear; (C) heat treatments
It is a paramount importance to find the deep cryogenic treatment conditions for minimizing wear of steels in the heat treatment industry. Supplementing deep cryogenic treatment to conventional heat treatment process will aid the manufacturers to attain better wear resistance of steel components. Deep cryogenic treatment is an affordable permanent treatment that influences the mechanical properties of the steel components. It alleviates the amount of retained austenite present in the conventionally treated steel . The removal of retained austenite results in an increase in hardness [2-3] and the process of “low temperature conditioning” of martensite, normally at liquid-nitrogen temperatures (-196°C), initiates nucleation sites for subsequent precipitation of large numbers of very fine carbide particles, resulting in increases in wear resistance . The deep cryogenic treatment is the process of cooling the samples from room temperature to 196 º C at a slow rate, soaked at -196 º C for about 12 hours to 24 hours, and slowly reheating to the room temperature, followed by tempering process . Charles. S and Arunachalam V.P  pointed out that the cryogenic treatment is a onetime homogenous process that provides significant extension in the performance and productive life of steel components namely brake rotors, gears, engines, machine parts, and transmission to machine tools, gun barrels.
Based on the literature survey, cryogenic treatment not only improves the wear resistance of certain steels but also it improves the fatigue life, dimensional stability, and compressive residual stress. Due to increase in compressive residual stresses, the heat-treated parts withstand external stresses during service without failure. This will lead to the good design for heat treatment .
1.2 Taguchi techniques
Recent research has revealed that the cryogenic treatment plays an important role in developing the tribological properties of...