EFFECT OF MANUFACTURING CONDITIONS ON THE PROPERTIES OF COMMERCIALLY PURE TITANIUM SEAMLESS PIPES

The properties of the commercially pure titanium seamless pipe, manufa ctured by the inclined rolling process, was investigated in comparison with the pipe by the conventional hot extrusion process. The results were as follows. (1)The titanium pipe without surface defects was succ essfully manufactured by the inclined rolling process. The pipe, rehea ted and finish rolled in the alpha phase temperature, had a good surfa ce properties and equiaxed structure after annealing heat treatment. ( 2)Post annealed tensile properties of the rolled pipes satisfied the A STM specification regardless of the reheating temperatures. The tensil e properties of the rolled pipes, which were reheated in alpha phase r egion, were almost equivalent to that of the excluded pipe. (3)Texture formed in the rolled pipe was similar to that of formed in the rolled plate when the pipes were reheated and finish rolled in alpha phase r egion. On the other hand, the texture in the rolled pipes which were r eheated and Finish rolled in beta phase region was transformed type. T he (0002) reflection was strongly accumulated in the extrusion and the transverse directions in the extruded pipe. (4)Longitudinal strength of rolled pipe, reheated and finish relied in beta phase region, was h igher than that of the pipes reheated in alpha phase region, due to th e accumulation of (0002) direction along rolling direction.