Pipe Forming with Curved U-Section to Prevent Edge Gaps
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Solution Overview
Problem
In the manufacturing of pipes by press molding, springback often occurs after O-shape bending, leading to gaps in the facing area, especially when using high-tensile strength steel, which complicates welding and affects consistency.
Innovation Solution
The method involves forming a U-shaped member with specific curved portions that have smaller radii of curvature, allowing for increased deformation and a closing force to bring the edges together, thereby reducing the likelihood of gaps in the facing area during O-shape bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If O-shape bending is performed on a metallic plate member to form a pipe, then the plate member is formed into a pipe shape with edges facing each other, but springback occurs after bending which separates the facing edges and creates gaps in the facing area
Solution Approach 1:
The patent applies preliminary action by forming a U-shaped member with specifically designed curved portions (with radii smaller than the final pipe cross-section) before the O-shape bending process. These pre-formed curved portions are strategically positioned to generate closing force during subsequent bending, preventing gap formation in the facing area. The U-shaped member serves as an intermediate form that anticipates and compensates for springback effects.
Solution Approach 2:
The patent utilizes parameter changes by varying the radii of curvature of different portions of the U-shaped cross-section. Specifically, the curved portions have radii smaller than the corresponding portions of the final pipe cross-section, creating a parameter difference that generates closing force during O-shape bending. This parameter variation allows the structure to self-adjust and eliminate gaps in the facing area.
2Strength
If high-tensile strength steel is used for the plate member, then the strength of the pipe is improved, but large springback occurs which makes welding difficult and causes inconsistency in welding quality
Solution Approach 1:
The patent converts the harmful effect of springback (which separates facing edges and creates gaps) into a beneficial closing force. By designing the U-shaped cross-section with curved portions having smaller radii than the final pipe cross-section, the springback that would normally cause gaps instead generates a closing force that pushes the facing edges together, ensuring consistent contact for welding and improving welding quality consistency in high-strength steel pipes.
3Force
If the curved portions of the U-shaped cross section have smaller radii of curvature than the pipe cross section, then the closing force increases to bring edges together, but the deformation required during press molding increases
Solution Approach 1:
The patent applies segmentation by dividing the U-shaped cross-section into multiple distinct curved portions (first curved portion, second curved portion, third curved portion, etc.), each with specifically controlled radii of curvature. This segmentation allows the deformation to be distributed across multiple zones rather than concentrated in one area, making the press molding process more manageable while still achieving the desired closing force effect in the facing area.
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 inhibits the occurrence of gaps in the facing area, ensuring consistent welding quality even with high-tensile strength steel, by utilizing a U-shaped cross section with strategically placed curved portions that increase the closing force between the edges.
Implementation Method 1
Springback sometimes occurs after the O-shape bending, which separates the facing edges and creates a gap in the facing area. Particularly, large springback can occur when the plate member is high-tensile strength steel.
Data Source
AI summary
A pipe is formed by press molding a U-shaped member including a U-shaped cross section. The U-shaped cross section includes at least five curved portions. The curved portions include a center curved portion facing an opening of the U-shaped cross section defined by both edges of the U-shaped cross section; a first right curved portion; a second right curved portion; a first left curved portion; and a second left curved portion. At least the center curved portion, the first right curved portion, and the first left curved portion each have a radius of curvature smaller than a radius of curvature of a corresponding portion of the pipe cross section.