Steel Pipe Press-Forming Seam Gap Control
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Solution Overview
Problem
The existing press-forming methods for steel pipes face challenges in maintaining a consistent seam gap, leading to variations that affect the constraining force needed for welding, resulting in potential welding failures and reduced productivity due to the need for manual adjustments and multiple measurement steps.
Innovation Solution
The method involves setting a fixed pressing-down amount in the final pass, ensuring that open seam edges contact the punch beam, and then applying an additional 9 mm of pressure to maintain a consistent seam gap, independent of the steel plate's yield strength, thereby reducing variations and eliminating the need for frequent die adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pressing-down amount in the final pass is increased to reduce seam gap, then the seam gap is reduced, but the spring back increases causing larger seam gap after releasing the load
Solution Approach 1:
The method applies preliminary action by performing additional pressing-down after the open seam edges contact the punch beam during the final pass. This extra pressing-down amount is applied in advance to compensate for the spring back that will occur when the load is released, ensuring the seam gap remains within the specified range after forming.
Solution Approach 2:
The method changes the pressing-down parameter dynamically during the final pass. When the open seam edges contact the punch beam, an additional pressing-down amount is applied. This parameter change allows precise control of the seam gap to account for material properties and spring back effects.
2Reliability
If the seam gap is not within the specified range, then welding quality deteriorates, but adjusting the die gap requires stopping production and manual intervention
Solution Approach 1:
The method implements self-service by enabling the press-forming process to automatically adjust and control the seam gap without requiring manual intervention. The additional pressing-down amount is automatically applied when the open seam edges contact the punch beam, allowing the system to self-regulate the seam gap within the specified range and maintain welding quality without stopping production.
Solution Approach 2:
The method changes the pressing-down parameter dynamically during the final pass to automatically control the seam gap. When the open seam edges contact the punch beam, an additional pressing-down amount is applied, allowing precise control of the seam gap to account for material properties and spring back effects without manual die adjustments.
3Reliability
If multiple measurement and adjustment steps are performed to control seam gap, then welding reliability improves, but the production time increases
Solution Approach 1:
The method ensures continuity of useful action by integrating seam gap control directly into the press-forming process flow. The additional pressing-down is performed continuously during the final pass without interrupting the production rhythm, eliminating the need for separate measurement and adjustment steps that would stop the production flow.
Solution Approach 2:
The method performs preliminary action by controlling the seam gap during the press-forming process itself through additional pressing-down, rather than performing separate measurement and adjustment steps after forming. This preliminary control of the seam gap eliminates subsequent intervention steps and maintains continuous production.
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 results in a significant reduction in seam gap variations, enhancing productivity by eliminating the need for modification forming and die adjustments, while ensuring consistent seam gaps across multiple steel pipes.
Implementation Method 1
a punch leading end portion 22 which is a leading end portion of a punch 2 of the upper die is pressed down to a position between two dies 1a, 1b, thereby applying bending deformation to the steel plate S
Implementation Method 2
When the punch pressing-down is released, since a spring back occurs, a seam gap of an open seam pipe becomes larger after releasing the punch pressing-down than the seam gap of the open seam pipe during the punch pressing-down
Data Source
Figure 1~2
Figure 3A~3
Figure 4~5C
AI summary
Provided are a method of press-forming a steel pipe with a small variation in a seam gap at butt welded portion and a method of manufacturing a steel pipe. In a method of press-forming a steel pipe by forming a steel plate by applying press bending to the steel plate a plurality of times, in accordance with a relationship obtained in advance between an additional pressing-down amount which is required further after a state that a predetermined seam gap is formed during applying press bending of a final time to an open seam pipe which is a material to be formed and the predetermined seam gap, forming with the additional pressing-down amount based on the relationship is applied to the open seam pipe from the state that the predetermined seam gap is formed during applying press bending of the final time to the open seam pipe which is the material to be formed.