| 摘要 |
PROBLEM TO BE SOLVED: To provide a titanium slab in which surface properties of a strip-like coil after the hot rolling are superior, even if omitting a breakdown process such as slabbing or forging, in the titanium slab casted by using an electron beam melting method and a plasma arc melting method.SOLUTION: A titanium slab is a commercially pure titanium cast-remaining slab manufactured by an electron beam melting method and a plasma arc melting method. At least a slab surface layer equivalent to a rolled surface is melted together with the material containing Fe, Cr, Ni being β stabilization element, and thereby a molten re-solidification structure comprising a fine acicular structure of 1 mm or more in depth is formed. The Fe concentration to this surface layer portion of 1 mm or the total content of each element obtained by substituting a portion or all of the Fe by one or two kinds of Cr and Ni is 0.10 mass% or more and 1.50 mass% or less. Powder, chip, wire and foil are used as the material containing the β stabilization element. Also, the electron beam heating and the plasma arc heating are used as means for melting the surface layer.SELECTED DRAWING: None |
