Method for continuously casting ingot made of titanium or titanium alloy

A method for continuous casting an ingot made of titanium or a titanium alloy by pouring molten metal prepared by melting titanium or a titanium alloy into a bottomless mold and drawing the molten metal downward while being solidified, the method comprising:

• a heating step, where, while a plasma torch is horizontally moved along a predetermined moving track above the surface of the molten metal in the mold, the surface of the molten metal is heated by plasma arcs generated by the plasma torch at a plurality of plasma torch positions along the predetermined moving track, wherein moving the plasma torch along the predetermined moving track sequentially positions the plasma torch in a plurality of predetermined plasma torch positions relative to the surface of the molten metal in the mold;
• a temperature-measuring step for measuring a temperature of the mold by each of a plurality of temperature sensors provided in a plurality of temperature sensor positions of the mold along the circumferential direction of the mold;
• and
• a heat input quantity control step for controlling heat input quantity per unit area applied from the plasma torch to the surface of the molten metal based on the temperature of the mold measured by the temperature sensors and a target temperature preset in each of the temperature sensors,
• wherein the heat input quantity per unit area applied from the plasma torch to the surface of the molten metal near a specific temperature sensor position of the plurality of temperature sensor positions is controlled in a region along the predetermined moving track that corresponds to the specific temperature sensor position.