Friction Stir Welded Blanks With Recessed Weld Ends for Stamping
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Solution Overview
Problem
Obtaining acceptable weld quality between aluminum or aluminum alloy blanks using traditional welding methods is challenging, particularly in forming tailor welded aluminum blanks for stamped parts, due to issues like weld defects that limit deformation and increase the risk of cracking during the stamping process.
Innovation Solution
The method involves forming tailor welded blanks by friction stir welding, followed by removing weld defects at the start and stop spots using machining tools to create recessed ends, which reduces residual plastic deformation and enhances the ductility of the weld, allowing for improved stamping without failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional welding methods are used to join aluminum blanks, then welding process is simple and fast, but weld quality is poor with defects that limit deformation and increase cracking risk
Solution Approach 1:
The patent replaces traditional thermal welding methods (arc welding, resistance welding) with friction stir welding, which uses mechanical friction and stirring action to join aluminum blanks. This mechanical approach eliminates thermal defects and creates superior weld quality with enhanced ductility and formability, directly resolving the contradiction between weld reliability and manufacturing ease.
Solution Approach 2:
The patent changes the fundamental welding parameters from thermal-based to mechanical-based processes. By controlling mechanical parameters such as stir speed, traverse speed, and plunge depth in friction stir welding, the process achieves high weld quality without the defects associated with traditional thermal welding methods.
2Reliability
If weld ends are left flush with blank edges, then manufacturing is simpler, but residual plastic deformation causes cracking during stamping
Solution Approach 1:
The patent extracts or removes the problematic weld start and stop spots from the friction stir weld, creating recessed ends that are set back from the blank edges. This extraction eliminates the regions of residual plastic deformation that would otherwise cause cracking during stamping, directly improving formability while the recessed design maintains manufacturing precision.
Solution Approach 2:
The patent performs preliminary removal of the weld end spots during the welding process itself, creating recessed ends before the stamping operation. This preliminary action prevents the formation of cracks during subsequent forming operations by eliminating the vulnerable regions of residual deformation.
3Reliability
If friction stir welding is used to join aluminum blanks, then weld quality and ductility are improved, but additional machining is required to remove weld defects
Solution Approach 1:
The patent merges the welding and machining operations into a single integrated friction stir welding process. The weld start and stop spots are removed during the welding operation itself, eliminating the need for separate post-weld machining steps. This combination maintains high weld quality while reducing overall process complexity.
Solution Approach 2:
The friction stir welding process performs self-machining by removing the weld end spots during the welding operation. The mechanical stirring action automatically excises the problematic start and stop regions, making the process self-sufficient and eliminating the need for additional external machining operations.
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 enhanced formability and predictability of friction stir welded tailor welded blanks, as demonstrated by higher average maximum true edge strain and reduced deviation in tensile testing, indicating improved properties for stamped parts.
Implementation Method 1
friction stir welding
Implementation Method 2
The weld is formed by friction stir welding (FSW)
Data Source
AI summary
A stamped part includes a first blank, a second blank, and a weld joining the first blank to the second blank. The weld includes opposing ends. At least one of the opposing ends of the weld is recessed from adjacent edges of the first and second blanks.