Titanium casting product for hot rolling and method for producing the same

Abstract

Provided is a titanium casting product made of titanium alloy, the titanium casting product being produced by electron-beam remelting or plasma arc remelting, comprising: a melted and resolidified layer in a range of 1 mm or more in depth at a surface serving as a surface to be rolled, the melted and resolidified layer being obtained by adding one or more kinds of β stabilizer elements to the surface and melting and resolidifying the surface. An average value of β stabilizer element concentration in a range of within 1 mm in depth is higher than β stabilizer element concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %. As the material containing the β stabilizer element, powder, a chip, wire, or foil is used. As means for melting a surface layer, electron-beam heating and plasma arc heating are used.

1 - 6 . (canceled) 
     
     
         7 . A titanium casting product made of titanium alloy, comprising:
 a layer containing one or more kinds of β stabilizer elements in a range of 1 mm or more in depth at a surface serving as a surface to be rolled,   wherein an average value of β stabilizer element concentration in a range of within 1 mm in depth is higher than β stabilizer element concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %.   
     
     
         8 . The titanium casting product according to  claim 7 ,
 wherein the β stabilizer element(s) is/are one or more of Fe, Ni, and Cr.   
     
     
         9 . The titanium casting product according to  claim 7 , containing one or more kinds of a stabilizer elements or neutral elements together with the β stabilizer element(s). 
     
     
         10 . A method for producing a titanium casting product, comprising:
 melting a surface serving as a surface to be rolled of a titanium casting product made of titanium alloy together with a material containing a β stabilizer element and then solidifying the surface to make an average value of β stabilizer element concentration in a range of within 1 mm in depth higher than β stabilizer element concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %.   
     
     
         11 . The method for producing a titanium casting product according to  claim 10 ,
 wherein the material containing the β stabilizer element is in a form of any of powder, a chip, wire, and foil.   
     
     
         12 . The method for producing a titanium casting product according to  claim 10 ,
 wherein the surface serving as the surface to be rolled of the titanium casting product made of titanium alloy is melted by electron-beam heating or plasma heating.