Development of TS590-980MPa Grade Galvannealed High Strength Steel Sheets with High Elongation Property

摘要

The elongation of dual phase (DP) steel is known to improve by Si addition. In order to clarify the influence of Si on elongation of the ferrite phase itself, Si-added ferrite single-phase steels were investigated. It was found that improved elongation resulted from an increase in work hardening by Si addition. Elongation improvement of the ferrite phase by Si addition was applied to DP steel in order to develop a high El type. The developed high El type TS590-980MPa grade high strength steel sheets show 20% higher elongation in ratio compared with the conventional steel.