Method of manufacturing seamless tube formed of titanium material

Abstract

A method of manufacturing a seamless tube formed of a titanium material, such as pure titanium or titanium alloys, by the use of the Mannesmann's method. At first, an ingot formed of the titanium material is processed under the conditions that a heating temperature is 850.degree. to 1,250.degree. C., the final temperature being 600.degree. to 1,100.degree. C., and a working degree being 50% or more so as to be turned into a solid billet. The resulting solid billet is subjected to a piercing within a temperature range of .beta. transus -100.degree. to 1,250.degree. C. so as to be turned into a hollow piece. In this piercing process, inclined rolls of a piercer are descaled. The resulting hollow piece is, in case of need, regulated a size thereof by elongating so as to be turned into a hollow shell. Subsequently, the resulting hollow shell is subjected to a reducing step (reducing conditions: temperature at an inlet side of the mill is 600.degree. to 1,100.degree. C. and a reduction of the outside diameter is 80% or more) by means of a reducer mill or to a sizing step (sizing conditions: temperature at an inlet side of the mill is 550.degree. to 1,150.degree. C. and a reduction of the outside diameter is 3 to 15%) by means of a sizer mill.