Experimental Study of the Effect of Siliconizing Parameters of Thermochemical Treatment of low Carbon Steel

Abstract

In order to use minimum time and save energy during siliconizing surface hardening of low carbon steel it is important to study the siliconizing parameters to obtain optimum conditions. In this work, the experimental design using the Taguchi method is employed to optimize the siliconizing parameters in the pack siliconizing surface hardening process. The siliconizing parameters evaluated are: siliconizing temperature, siliconizing time, silicon potential (ratio of silicon powder to bean pod ash (BPA) nanoparticle) and tempering temperature. The results showed that case depth and hardness values increased exponentially by increasing siliconizing temperature and time. Optimum values of hardness were obtained at a siliconizing temperature of 1000 ^∘C, siliconizing time of 5 hours, silicon potential of 75 wt.% silicon/25 wt.% BPA and tempering temperature of 200 ^∘C. With percentage contribution of: siliconizing temperature (79.86 %), siliconizing time (12.54 %), silicon potential (5.34 %) and tempering temperature (2.26 %). Silicon powder and bean pod ash nanoparticles can be effective for use as siliconizing materials in the ratio of 75 wt.% silicon/25 wt.% BPA. The activation energy (Q) for research work was determined as 333.89 kJ.mol⁻¹. The growth rate constant (K) ranged from 6.78×10⁻⁸ to 2.05×10⁻⁶ m².s⁻¹. The case depth, hardness values and wear rate of siliconized mild steel at these operating conditions can be used for technological and industrial applications such as gears and cams.