| Title |
Strengthening of Metastable Austenitic Stainless Steels by Reversion Treatment |
| Authors |
김영환(Y . H . Kim) ; 안용식(Y . S . Ahn) ; 정해용(H . Y . Jeong) ; 강창용(C . H . Kang) ; 정병호(B . H . Jeong) ; 김창규(C . G . Kim) |
| Abstract |
Austenite phase in metastable Fe-Cr-Ni ternary stainless steels was fully transformed to martensite(α`) phase by 90% cold rolling and this martensite single phase reverted to austenite again at temperature range from 773 to 1073K. The mixed phase structure consists of reversed ultra-fine austenite grains with the diameter of 0.5 ㎛ and remained α`. Their mechanical properties were investigated as a function of α` content and austenite stability. The main results may be summarized as follows : (1) The good combination of high yield strength over 800MPa and elongation near 20% was obtained from the mixed structure containing a higher content of α`, as Ni and Cr contents are lowered. (2) In the mixed structure, elongation was greatly affected by the TRIP behavior in the initial stage of deformation. (3) The ultra-fine graining of austenite more stabilized the mixed structure. (4) The abrupt drop of elongation in the mixed structure occurred at a limited content of α` in according to the difference of austenite stability. This phenomenon was well explained by the criterion equation of the plastic stability. |