DFG Project PF 394/3–1

Simulation of flow, solidification and strip forming during the production of broad strip using the two-roll casting process

Flow, macro­sco­pic soli­di­fi­ca­ti­on and strip forming were inves­ti­ga­ted for strip cas­ting by phy­si­cal and nume­ri­cal simu­la­ti­on. Laser-opti­cal flow mea­su­re­ment tech­ni­ques (DPIV, LDA) were appli­ed to the phy­si­cal water model of the melt pool. Here the basic flow and tur­bu­lence struc­tures were deter­mi­ned. The vali­da­ted CFD simu­la­ti­on of the water flow was used to simu­la­te the flow and macro­sco­pic soli­di­fi­ca­ti­on of the steel melt on the cas­ting rol­lers. The main influence on the flow field in the melt pool is exer­ted by the immersi­on tube con­cept. The free jets ente­ring the pool gene­ra­te are­as of high flu­id velo­ci­ties and high tur­bu­lence. Due to mixing, this leads to low sub­coo­ling of the steel melt and cau­ses slower strip shell growth. In calm are­as, the strip shell grows fas­ter. This leads to an uneven sur­face tem­pe­ra­tu­re of the cast strip. Here a fun­da­men­tal agree­ment is found bet­ween the results of the CFD simu­la­ti­on and the mea­su­re­ment of the sur­face tem­pe­ra­tu­re. The increase of the pool height leads to an even soli­di­fi­ca­ti­on on the cas­ting rolls in spi­te of the increased mass flow, inde­pen­dent of the immersi­on tube con­cept. The influence of the flow decreases.

The CFD simu­la­ti­on of the tran­si­ent pool flow was car­ri­ed out for both water and steel melt with con­side­ra­ti­on of soli­di­fi­ca­ti­on. The shape of the free sur­face is repro­du­ced by nume­ri­cal simu­la­ti­on. While a sta­tio­na­ry flow field is found in the simu­la­ti­on of the water flow, cycli­cal fluc­tua­tions are found in the simu­la­ti­on of the steel melt.

The under­stan­ding of the rela­ti­onships bet­ween flow and soli­di­fi­ca­ti­on and the effect on strip for­ma­ti­on was con­sider­a­b­ly extended.

Logo DFGThe pro­ject was fun­ded by the Deut­sche For­schungs­ge­mein­schaft (DFG) under the refe­rence num­ber PF 394/3–1.