The low temperature aluminizing kinetic of hot work tool steels

Conventional aluminizing procedures are mostly conducted on temperatures well above 900 °C, and can last for hours. When applied on hot-work tool steels, aluminizing has to be done at notably lower temperatures, hence of grain growth and carbide formation prevention, as well as creep resistance improvement. The kinetics of aluminium coating formation on hot work tool steels was studied in the temperature range of 550 to 610 °C. The pack Al content was varied from 5 to 15 wt pct and aluminizing time from 1 to 9 hours. The halide activator AlCl3 was applied. A series of statistically designed experiments were conducted to determine how key process factors influence aluminide coatings formation. A Box - Behnken experimental design was used to evaluate three process factors over three levels. The microstructures of coated samples were analyzed by SEM microscope. GDOS and EDX were employed to investigate element distributions in the coating layer.