Taguchi approach to optimize pack aluminization parameters

Abstract EN

Pack aluminization has been rapidly developed and widely used in many fields due to its superior properties of coating.

Surface is the only part of the component which has to coexist with external environment.

Majority of engineering failures originate from the surfaces and components degrade in service leading to failures such as fatigue, wear, corrosion and oxidation.

The present study deals with the surface modification of steel base through diffusion of aluminium by aluminium pack cementation for improving wear and corrosion resistance.

The material chosen for study is medium carbon steel.

Effect of varying weight percentage (wt.

%) of halide activator (NH4Cl) at different diffusion temperatures and times on the microstructure and microhardness of aluminized specimens was studied.

Taguchi robust design technique using MINITAB13 was used to rank several factors that may affect the microhardness and microstructure in order to formulate the optimum conditions.

The Taguchi orthogonal array L9 (33) was used for experimental design with three level of consideration for each factor.

The respone (Microhardness) was analyzed based on the Taguchi’s signal-to-noise ratio.

The use of 4 % wt.

of (NH4Cl) at 5hr and diffusion temperature of 700oC seems to be the optimum condition, where the surface hardness could be increased to 1000Hv when aluminized.

X-Ray diffraction studies have been confirmed the presence of aluminides in the surface layer, which could be instrumental in the significant increase in the surface hardness.