Effect of manufacturing conditions on the properties of Ti-6Al-4V seamlesspipes

Ti-6Al-4V seamless pipe was manufactured by the inclined rolling process to take advantage of its higher productivity than the conventional hot extrus ion process, Properties of the relied Ti-6Al-4V seamless pipe was investiga ted. Also, the pipes, extruded at alpha + beta phase temperature and beta p hase temperature, were compared each other. The inclined rolling process wa s successfully applied to produce Ti-6Al-4V seamless pipes. The pipes posse ssed uniform fine accicular microstructure and no surface flaws, The balanc e between 0.2% proof stress and elongation was optimum in the rolled pipe, followed by the alpha + beta extrude pipe with elongated primary alpha phas e, and the beta extrude pipe which consisted of coarse beta grains with acc icular structure. Crystallographic texture was weakly formed in the rolled pipe, which was similar to that of rolled plate. Similar, but slightly inte nse texture was formed in beta extruded pipe. Tensile and fracturing proper ties were isotropic in the rolled and the beta extruded pipe. On the other hand intense texture was formed in the alpha + beta extruded pipe. C axis d irection of titanium alpha phase was intensely orientated to bath the trans verse and the longitudinal directions. Tensile and fracturing properties we re anisotropic in the alpha + beta extruded pipe, due to the intense textur e formation. The degree of anisotropy in the properties was correlated with the ratio of the C axis orientation fraction, regardless their manufacturi ng processes.