Strain hardening of steels at large strain deformation. Part II: Strain hardening of pearlitic and austenitic steels and the estimation of mechanical properties

Abstract

Continuing from Part I of this work, the strain hardening behaviour of eutectoid pearlitic and austenitic steels was investigated. Pearlitic steels with different lamellar distance and colony size were produced with sufficient deformability to obtain stage IV. The influence of microstructure on strain hardening of these steels can be described more accurately by an extended Kocks model (hybrid model) than the Kocks model. However, as for the Kocks model, the hybrid model is also violated in stage IV. The strain hardening rate of the pearlitic steels is much higher than of ferritic steels. With the help of austenitic stainless steels with different Ni content, the differences between the strain hardening behaviour of b.c.c. and f.c.c. steels were investigated. A significant influence of Ni content on strain hardening was found. Finally, based on the relationship between microstructure and strain hardening, the dependence of the ultimate tensile stress and uniform elongation on microstructures was estimated and compared with experimental results.