Numerical simulation of the solidification process of Cu-0.45% Sn alloy in upward continuous casting

Upward continuous casting is the key process in the production of contact wire for electric railway. The stability of the process and the quality of the produced billet are directly related to the performance of the contact wire and ultimately the safety of the railway operation. To ensure the quality of continuous-casting billet, the optimal process conditions need to be experimentally determined, which is not only costly but also time-consuming. To facilitate this optimisation process, the simulation of the solidification process of Cu-0.45%Sn alloy in upward continuous casting is described in this paper to assess the influence of casting temperature, upward continuous casting speed, the time of stop-pull, and primary cooling water flow rate on the liquid core length. The results show that the speed of upward continuous casting exhibits a great influence on the liquid core length, while the casting temperature has only little influence. In a certain range of the ratio of stopping time to pulling time, the quality of updraft Cu-0.45%Sn alloy billet is improved; exceeding a certain ratio results in a decrease of the surface quality and an increase in internal and external defects. The liquid core length of the continuous casting rod decreases with the increase of the cold water flow rate, and properties are stable when the flow rate reaches 0.45 m3·h−1. For a billet with a diameter of 20 mm, the appropriate upward continuous casting process parameters are determined as a casting temperature of 1175 °C, an upward continuous casting speed not exceeding 25 cm·min−1, a ratio of stopping time to pulling time not exceeding 2.13, and a cooling water flow rate of 0.45 m3·h−1.