| 摘要 |
This alpha+beta-type titanium alloy plate is used for a welded pipe in which the rolling direction is employed as the circumferential direction, the titanium alloy plate having a composition comprising, in mass%, 0.8 to 1.5% Fe, 4.8 to 5.5% Al, less than or equal to 0.020% N, and O in a range satisfying Q=0.14 to 0.38, with the remainder comprising Ti and impurities, wherein: the texture in the plate-surface direction comprises a first crystal grain group oriented in a region where the angle theta, which is an angle formed between the c axis and the normal direction to the plate in a (0002) pole figure of the alpha phase having a hexagonal crystal structure, is from 0 to 30°, and a second crystal grain group oriented in a region where said angle theta is from 80 to 100° and where the angle Phi, which is an angle formed between the plate width direction and a projection line of the c axis onto the plate surface in a (0002) pole figure of the alpha phase, is from -10 to 10°; and the ratio (second crystal grain group/first crystal grain group) between the maximum value of the relative X-ray intensity found from the bottom surface of the alpha phase of the first crystal grain group and that of the second crystal grain group is greater than or equal to 5.0. |
