MODELLING AND OPTIMIZATION OF TECHNOLOGICAL PARAMETERS IN HEAT TREATMENT OF AISI 1045 USING RESPONSE SURFACE METHODOLOGY

This work is an experimental contribution followed by an optimization in order to examine heat treatment effect on hardness variances of AISI 1045 structural steel. Temperature (°C), holding time (min.) and cooling rate (slow, very fast) are the main input control parameters selected for the present investigation. A Taguchi L32 experimental plan is applied to determine the resulting influence in terms of Vickers hardness (HV), a principal mechanical property to assess heat treatment effectiveness. Percentage contribution for each control parameter is calculated using ANOVA with 95 % confidence interval. It is found that fast cooling is the most dominant factor on HV followed by temperature level. An optimization is presented based upon response surface methodoly (RMS) and the desirability function (DF) approach in order to highlight the conditions which confer the best overall mechanical strength of such steel.