The effect of TRIP steel surface chemistry on reactive wetting during hot Dip Galvanizing

The effect of intercritical annealing temperature, annealing time and process atmosphere on the selective oxidation of a 1% Si - 0.5 % Al TRIP-assisted and its subsequent reactive wetting during continuous galvanizing were studied. It was determined that good reactive wetting was achieved when using a higher intercritical annealing temperature of 797 °C but not when using an intercritical annealing temperature of 750 °C. When using the intercritical annealing temperature of 750 °C, the wettability of the steel was improved by using a more reducing annealing atmosphere. The addition of an isothermal bainite hold at 465 °C in the thermal cycle resulted in small changes in the steel surface chemistry and did not have an adverse effect on the reactive wetting behavior of the steel. © 2008 MS&T08®.