Abstract：The closing behavior of porosity in continuous casting steel slab during rough transverse rolling was investigated using FE-code, ANSYS/LS-DYNA. Process parameters of extra-heavy Q345 steel plate obtained from a Chinese iron and steel works were used as a reference. The slab of initial width 3500mm and thickness 320mm was rolled down to 140mm. The results indicate that rectangular porosity in extra-heavy plate can be closed with appropriate reduction. The size and location of porosity have evident influence on closing behavior. Surface porosity needs the largest critical reduction to close, and the critical reduction of porosity located at 1/8 thickness is lowest. It’s an effective method to avoid porosity by increasing pass reduction over 18% for extra-heavy plate rolling. The larger of λ(ratio of porosity length to height), the smaller of critical reduction needs for closing. When λ increases from less than 1 to more than 1, the critical reduction rapidly decreases, but it slightly decreases with λ further increasing. Porosity closing as double “Y-shape” with λ<1, and like a “Z-shape” when λ≥1.
2009, Vol. 1 
