Titanium Alloy Billet Piercing With Stable Mandril Positioning
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Solution Overview
Problem
Titanium alloy billets are difficult to pierce due to their high elastic modulus and deformation resistance, often causing sticking in rotary piercers and loss of mandril position, requiring precise process parameter settings for ideal microstructure.
Innovation Solution
A method using a Mannesmann rotary piercer with specific geometric configurations, temperature control, and centering device distribution to pierce titanium alloy billets, involving a feeding angle of 6-18°, cross angle of 15°, roll speed of 30-90 rpm, and plug advance of 5-15 mm, along with heating to 930-990°C and cooling in air, to produce tubes with a bimodal microstructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two-roll rotary piercing is used on titanium alloy billet, then piercing can be achieved, but the billet tends to be stuck in the rotary piercer and the mandril loses working position due to high deformation resistance
Solution Approach 1:
The patent applies parameter changes by optimizing the feeding angle (6-18°) and cross angle (15°) of the rotary piercer, controlling the diameter reduction ratio (6-12%), and regulating the heating temperature (930-990°C) to reduce deformation resistance and prevent sticking while maintaining mandril position stability
Solution Approach 2:
The patent implements preliminary action by heating the titanium alloy billet to 930-990°C before piercing to reduce its deformation resistance, and by pre-positioning multiple centering devices to ensure accurate mandril positioning throughout the piercing process
2Ease of manufacture
If heating temperature is increased to reduce deformation resistance, then piercing becomes easier, but temperature control precision becomes more challenging
Solution Approach 1:
The patent implements feedback control by monitoring the heating temperature and adjusting it within the optimal range of 930-990°C to achieve sufficient reduction in deformation resistance while preventing excessive temperature rise that would compromise manufacturing precision
3Manufacturing precision
If multiple centering devices are added to maintain mandril position, then positioning accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the centering function into multiple discrete centering devices positioned at different locations along the mandril, with each device contributing to overall positioning accuracy while allowing independent adjustment and maintenance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively prevents sticking and maintains mandril position, achieving accurate and stable piercing with minimal temperature rise, resulting in titanium alloy tubes with consistent bimodal microstructure and controlled diameter-thickness ratio.
Implementation Method 1
heating a titanium alloy solid billet to 930-990° C.
Implementation Method 2
cooling in air
Data Source
AI summary
A method for piercing a titanium alloy solid billet, the method including: 1) providing a Mannesmann rotary piercer including two rollers, a feed channel, a plurality of centering devices, and a mandril including a plug; fixing the mandril using the plurality of centering devices, where the Mannesmann rotary piercer has a feeding angle of 6-18°, a cross angle of 15°, and a roll speed of 30-90 rpm; 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 of the mandril, and driving the titanium alloy solid billet to pass through the plug of the mandril, thereby piercing the titanium alloy solid billet and yielding a titanium alloy tube.