PURPOSE: To strengthen a vessel and to enable thinning of the vessel by forming embossed working pattern to a trough type or pipe type vessel.

CONSTITUTION: The embossing pattern is formed on a raw material by the embossed working and the pipe type vessel is formed by press bending working. In this vessel, the metal material or returned material having the same material as the vessel is changed and this vessel is horizontally arranged in a plasma melting furnace, etc. The material is in order melted from end part of the vessel by using plasma electron beam and the molten metal produced during this is poured into the mold to finally obtain the ingot. Therefore, as the embossed working is executed to the vessel, the thickness of the vessel can be thinned, and the working is facilitated and the production cost is reduced.