Method for continuously casting slab containing titanium or titanium alloy

A method for continuously casting a slab containing titanium or a titanium alloy by pouring molten metal formed by melting titanium or a titanium alloy into an open mold having a rectangular cross-section where the molten metal is solidified and withdrawn from the bottom of the mold,

• wherein the method includes
• pouring the molten metal into the mold from one of the paired shorter sides of the mold, and
• dividing, in a direction of longer sides of the mold, a surface of the molten metal in the mold into a metal inlet side, where the molten metal is poured, and a side opposite the metal inlet side, heating the surface of the molten metal on the metal inlet side of the mold by a first heat source, which is configured to turn in a horizontal plane over the surface of the molten metal on the metal inlet side, and heating the surface of the molten metal on the side opposite the metal inlet side by a second heat source, which is configured to turn in a horizontal plane over the surface of the molten metal on the side opposite the metal inlet side,
• wherein the surface of the molten metal on the metal inlet side is heated by the first heat source in the heating step so that the following formulas:
• q≧0.87 and c≦11.762q+0.3095 are satisfied where c is a cycle time [sec] of turning movement of the first heat source, and q is an average amount of heat input [MW/m2] determined by accumulating an amount of heat input, which is applied by at least the first heat source to a region of contact between an upper surface of the slab on the metal inlet side and the mold, along the path of turning movement of the first heat source, and dividing the resultant accumulated value by the cycle time c.