POSCO Holdings Inc.
STEEL SHEET PLATED WITH AL-FE ALLOY FOR HOT PRESS FORMING HAVING EXCELLENT CORROSION RESISTANCE AND HEAT RESISTANCE, HOT PRESS FORMED PART, AND MANUFACTURING METHOD THEREFOR

Abstract:

The present invention provides a steel plate plated with an aluminum-iron alloy for hot press forming, the steel plate comprising a base steel sheet and an alloy plated layer formed on the base steel sheet, wherein the alloy plated layer comprises: an alloyed layer (I) formed on the base steel sheet and containing, by weight, Al: 5-30%; an alloyed layer (II) formed on the alloyed layer (I) and containing, by weight, Al: 30-60%; and an alloyed layer (III) formed on the alloyed layer (II) and containing, by weight, Al: 20-50%, wherein the alloy layer (II) has a FeAl (Si) alloy phase dispersed and distributed therein, the FeAl(Si) alloy phase comprising, by weight, Al: 20-50% and Si: 5-20%, and the number density of the FeAl(Si) alloy phase having a circle-equivalent diameter of 5 .mu.m or less is 103/mm2 or more.