Hot strength and hot ductility of titanium alloys—a challenge for continuous casting process

Hot workability of Ti-6Al-2Sn-4Zr-2Mo, Ti-10V-2Fe-3Al, Ti-15V-3Cr-3Sn-3Al and NiTi have been examined up to the melting point, and compared with those of Ti-6Al-4V and carbon steels. Titanium alloys do not show any embrittlement in zone II, which is the best region of hot rolling. The embrittlement occurs just below the β transus temperature. Based on these results, it is suggested that titanium alloys can be successfully produced by the continuous casting and hot direct rolling processes if cast material passes the unbending point at temperature above β transus in order to avoid the embrittlement in zone III. Since the strength level of titanium alloys in the β region is very low, it is also easier to unbend the strand. Hot direct rolling immediately after the casting is also an effective method for obtaining good product shapes free from surface oxidation and also has substantial cost benefits.