Structure and properties of trip steel after heat treatment

Abstract

In transformation induced plasticity (TRIP) steels, proper microstructure is essential. The TRIP effect provides the material with high plasticity owing to high volume fraction of ductile phases (ferrite and austenite) in microstructure. In consequence, it provides high hardening through deformation and transformation. The hardening is caused by transformation of retained austenite to martensite. Suitable microstructure for TRIP effect can be obtained by either thermomechanical or heat treatment. present paper describes development of an intercritical annealing technology, which guarantees fine-grained microstructure formation consisting of appropriate fractions of ferrite, lower bainite and retained austenite. Such structure is suitable for further cold forming with TRIP effect hardening. Real products like tubes or sheets were processed from derived experimental results.