Abstract:By means of quantitative tension, tint-etched metallograph, SEM, TEM and XRD techniques, the tensile properties, transformation behavior and strain hardening behavior during tensile straining of low silicon TRIP steel contained niobium were investigated. The results indicated that this kind of TRIP steel combines high strength and high ductility, while tensile strength can reach 700MPa level, total elongation is above 34%. The relationship between the transformation rate of retained austenite and true strain in uniaxial tensile can be expressed as ln[(Vγ0-Vγ)/(Vγ0-Vγu)]=lnk-cε, as the strain increases, the c value determining the transformation rate decreases, the stability of retained austenite is strengthened. During uniform plastic deformation, Variation of instantaneous strain hardening n* value versus true strain ε has a relation with the martensitic transformation volume fraction of retained austenite.