Effect of Silicon in Steels and Galvannealing Heat Cycles on Powdering Behavior of High Strength Galvannealed Steels
고강도 용융아연 도금강판의 파우더링 특성에 미치는 실리콘 및 합금화 열처리의 영향
이호종;오용택;김종상;
순천대학교 공과대학 재료금속공학과;포항제철 기술연구소;
Hot-dip galvannealed sheet (GA) with high strength of $45kg/mm^2$ in tensile strength, has developed for automotive applications. However, for a successful application, the powdering behaviour of GA must be minimized. The powdering of galvannealed coatings was reduced as the silicon content in the steel increased. Rapid heating and rapid cooling rate during the galvannealing process improved the powdering resistance due to the suppression of not only the ξ phase, but also the $ Gamma _1$, phase. An analysis of the Fe-Zn alloy phases and its relation to the powdering behaviour are discussed with SEM micrographs.
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