A Laboratory Study on the Processing Factors for Cold-rolled Dual Phase Sheet Steels

Abstract

Dual Phase structure formation in the intercritical annealing method is strongly affected by the cooling stage. Role of the cooling stage consists of (a) carbon enrichment into the untransformed austenite, (b) avoidance of pearlite formation and, (c) martensite and retained austenite formation. Significance of a two-stage cooling can be explained on the above basis.
Employment of a rapid heating and a short-time intercritical holding produces a highly bake-hardenable dual-phase steel with a large work-hardening capacity. This phenomenon is supposedly related to a transient state of solute carbon partitioning in the intercritical temperature range.