A pivotable tundish (1) for continuous casting a metal alloy. The tundish includes a body (3) with a first chamber (5), a second chamber (7), a first passage (12) between the first chamber and the second chamber, and a second passage (16) between the second chamber and a mold (9). The first chamber is adapted to receive and hold a base metal constituting the base for forming the metal alloy by addition of alloying elements. The metal alloy is fed from the second chamber to the mold through the second passage. The second chamber further includes a first portion (30) and a second portion (32), and a third passage (36) between the first portion and the second portion. In the casting state the metal alloy is formed while casting by adding the alloying elements to the second portion of the second chamber.