Disk Roll Skew Angle for Seamless Pipe Piercing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piercing and rolling methods for seamless tube manufacturing at increased tube expansion ratios suffer from material peeling and wall thickness deviations in the hollow shell.
Innovation Solution
The method involves using a piercing and rolling apparatus with cone-shaped main rolls and disk rolls, where the disk rolls are arranged at a fixed skew angle, ensuring an average thickness ratio greater than 0.8 and specific distance and width ratios between the peripheral groove bottoms and the billet diameter to maintain constant gaps and prevent shifting, thereby enhancing rigidity and reducing peeling and wall thickness deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the tube expansion ratio is increased to produce thinner-walled seamless tubes, then the wall thickness is reduced, but material peeling and wall thickness deviations occur
Solution Approach 1:
The patent applies parameter changes by optimizing the disk roll skew angle δ and the ratio of disk roll average thickness to billet diameter (Dw1/d ≥ 0.8). By adjusting these parameters, the patent achieves stable gap maintenance between main rolls and disk rolls during piercing and rolling, preventing material peeling and wall thickness deviations even at increased tube expansion ratios.
Solution Approach 2:
The patent addresses the dynamic instability caused by billet swinging during piercing and rolling. By properly setting the disk roll skew angle and maintaining appropriate gaps, the system dynamically stabilizes the billet position, preventing material peeling while enabling increased tube expansion ratios for thinner-walled tube production.
2Ease of operation
If disk rolls are arranged with inclined skew angle to suppress billet swinging, then rolling smoothness is improved, but gaps form between disk rolls and main rolls causing hollow shell extrusion
Solution Approach 1:
The patent resolves this contradiction by optimizing the disk roll skew angle δ and the geometric parameters (Dw1/d ≥ 0.8, Ds/d = 9 to 16, Dw2/d ≥ 0.8). These parameter changes enable the disk rolls to suppress billet swinging while maintaining appropriate gaps that prevent hollow shell extrusion, achieving both rolling smoothness and dimensional accuracy.
3Manufacturing precision
If the rigidity of disk roll supporting device is increased to prevent position shifting, then gap stability is improved, but device complexity increases
Solution Approach 1:
The patent achieves gap stability through parameter optimization rather than increasing structural complexity. By setting the disk roll skew angle δ and the ratio Dw1/d ≥ 0.8, the patent maintains stable gaps between main rolls and disk rolls without requiring overly complex supporting devices, balancing precision with simplicity.
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
This approach effectively prevents material peeling and wall thickness deviations, enabling the production of seamless tubes with thinner walls without defects even at higher tube expansion ratios.
Implementation Method 1
the main rolls 1R, 1L are rotated in the direction shown in Fig. 3, for instance. As shown in Fig. 1, the main rolls 1R, 1L are in mutually twisted positions owing to the setting of the feed angle ß. When the main rolls 1R, 1L are rotated in the direction indicated by the arrows in the figures, the billet 6 is inserted between the main rolls and pierced while it is rotated in the clockwise direction
Implementation Method 2
In order to suppress this swinging, a pair of disk plates are arranged above and below the main rolls 1R, 1L... These disk rolls 10 are rotated along with the advancement of the billet and suppress the swinging of the billet 6 so that the rolling may proceed smoothly
Implementation Method 3
the billet 6 is inserted between the main rolls and pierced while it is rotated in the clockwise direction... the billet is pierced and rolled by the main rolls 1R, 1L and the plug 7 to give a hollow shell 9
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
[Objective] To provide a method and apparatus for seamless tubes in which the occurrence of material peeling can be prevented even when the skew angle δ and tube expansion ratio are increased. [Means for solution] A piercing-rolling method for seamless tubes using a piercer, which is provided with a pair of cone-shaped main rolls and a pair of disk rolls, each pair being arranged in an opposing manner with a pass line therebetween as a center axis, and a plug whose center axis coincides with the pass line, wherein a billet to be pierced and rolled is advanced while being spirally rotated by a drive rotation of the main rolls; the method of which is characterized in each of the disk rolls being arranged in an inclined state at a fixed skew angle δ to the pass line.