STUDY ON WORK HARDENING BEHAVIOR OF FERRITIC-BAINITIC DUAL PHASE STEELS

In this work, the stress-strain curve of two types of dual phase steels namely ferriticbainitic and ferritic-martensitic with 0.16% C and 1.2% Mn have been obtained using tensile tests. Ferritic-Bainitic dual phase steels were intercritically annealed under different conditions and subsequently quenched in a salt bath, while FerriticMartensitic dual phase steels were water quenched. The stress-strain data were checked using Hollomon`s equation. The results showed that both types of dual phase steels had two stages of work hardening and each stage had a different work hardening exponent. The effect of volume fraction of hard phases (bainite and martensite) on ultimate tensile strength, total elongation and work hardening exponent were also investigated. The results indicated that increasing the volume fraction of hard phase increases the UTS while decreases the work hardening exponent and total elongation. Keyword: dual phase steels, Work hardening, Ferrite, Bainite, Martensite, Mechanical properties.