Optimization of Cyclic Oxidation Parameters in Steel-T21 for Aluminization Coating Using Taguchi-ANOVA analysis by MINITAB13

Abstract

The increasing demands for high quality coatings has made it inevitable thatthe surface coating industry would put more effort into precisely controlling thecoating process relative to media for which is subjected. Statistical design ofexperiments is an effective method for finding the optimum cyclic oxidationparameters for aluminization coating. In the present investigation, an attempt is madeto produce high-quality aluminization coating by optimizing the cyclic oxidationparameters following a (L9-33) Taguchi-design approach. (L9-33) Taguchi orthogonalarray has been used to determine the signal to noise ratio (S/N). The oxidationparameters that were varied include the Temperature (600,700,800oC), Time(15,20,25hr at 5hr cycle) and Media (Air,CO2,H2O). The coating characteristics werequalitified with respect to parabolic oxidation rate constant (KP). The performance ofthe coating was qualitatively evaluated using cyclic oxidation testing. Analysis of theexperiments using Taguchi method indicated that 800oC,25hr and CO2 media are to bethe optimum cyclic oxidation conditions for pack aluminization. The contribution ofeach of these parameters to the parabolic oxidation rate constant (KP) was determinedemploying an analysis of variance (ANOVA) and the effect of the level of eachparameter was determined using Taguchi analysis. ANOVA results show thattemperature and media are the parameters that most significantly affect the parabolicoxidation rate constant (KP) compared to time.