Method for piercing titanium alloy solid billet

A method, comprising:

• 1) providing a Mannesmann rotary piercer comprising two rollers, two guide plates disposed in an arrangement of plane symmetry and have a first symmetry plane intersecting the two rollers and a second symmetry plane perpendicular to the first symmetry plane, a feed channel, a plurality of centering devices, and a mandrel comprising a plug;
• fixing the mandrel using the plurality of centering devices;
• wherein
• the mandrel defines a passing line;
• the Mannesmann rotary piercer has a feeding angle of 6-18°, a cross angle of 15°, a roll speed of 30-90 rpm, and a plug advance of 5-15 mm;
• the feeding angle refers to a projection of an included angle between an axis of one of the two rollers and the passing line on the second symmetry plane, and the cross angle refers to a projection of an included angle between the axis of one of the two rollers and the passing line on the first symmetry plane;
• the plug advance refers to a distance between a front end of the plug and a roll gorge along the passing line, the roll gorge refers to a position of the two rollers where a distance between the two rollers is minimum;
• and
• a diameter reduction ratio of the billet is set as 6-12%;
• 2) heating a titanium alloy solid billet to 930-990° C.;
• 3) transferring the titanium alloy solid billet to the feed channel of the Mannesmann rotary piercer;
• and
• 4) aligning the titanium alloy solid billet with the plug, and driving the titanium alloy solid billet to pass through the plug, thereby piercing the titanium alloy solid billet and yielding a titanium alloy tube;
• wherein the Mannesmann rotary piercer comprises three cams for each centering device;
• an included angle of each two of the three cams is 120°, and the mandrel is disposed in a hole enclosed by the three cams for each centering device.