| Title |
Pesearch Paper / Mechanical Behavior : Effect of Heat - Treatments on Formability in a 0.1C-1.5Si-1.5Cu TRIP - Aided Cold - Rolled Steel Sheet |
| Authors |
송병환(Byoung Hwan Song),이창길(Chang Gil Lee),김성준(Sung Joon Kim),최일동(Il Dong Choi) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
The effects of retained austenite on the formability of a 0.1C-1.5Si-1.5Mn-0.5Cu TRIP-aided cold rolled steel sheet were investigated after various heat treatments. Tensile tests and limiting dome height (LDH) tests were conducted, and the changes of retained austenite volume fractions as a function of tensile strain were measured using X-ray diffraction. The results showed plausible relationships between the formability and retained austenite parameters such as stability and initial volume fraction of retained austenite. The formability was improved with the increase of volume fraction of retained austenite. However, when the volume fraction of retained austenite was same, better formability was obtained in the specimens with high stability of retained austenite, meaning that the strain induced transformation of retained austenite to martensite could be stably progressed and resulted in the improvement of formability. Thus, the conditions of intercritical annealing and isothermal treatment in TRIP-aided cold rolled steel sheets should be established in consideration of volume fraction and stability of retained austenite. It was concluded that the effects of retained austenite on the formability of TRIP-aided cold rolled steel sheets could be clearly understood in terms of the stability and the initial volume fraction of retained austenite. |