| 摘要 |
A method for predicting phase fraction existing in a hot rolled transformation induced plasticity steel produced after hot rolling to overcome limitation of a conventional technology is provided. A method for calculating phase fraction of a hot rolled strip comprises: a first step of inputting a composition and an initial temperature of a strip; a second step of determining type and initial phase fraction of a phase generated according to the initial composition and temperature; a third step of repeatedly performing a process until a stable phase is changed, the process of using the calculated phase fraction(Xi+1) as an initial phase fraction when calculating a phase fraction at a very small amount of time(ÝÈti+1) of a next step of the calculated phase fraction(Xi+1) by determining a temperature after a very small amount of time(ÝÈti) according to isothermal or cooling patterns according to time, determining an equilibrium phase fraction at the determined temperature using a thermodynamic model, and calculating a phase fraction(Xi+1) changed from the initial phase fraction(Xi) using the equilibrium phase fraction; and a fourth step of returning to the second step the stable phase is changed, wherein an actual phase fraction is calculated by the following relational expression 1 by using the phase fraction calculated in the third step: X^r i+1 = Xi+1 Î X^0 gamma, wherein X^r i+1 represents a generation fraction of a current stable phase within an actual strip, and X^0 gamma represents a residual austenite fraction when the current stable phase is initially formed. |
