Friction Stir Welding Gap Sealing for Corrosion Resistance
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Solution Overview
Problem
Lap butt welds produced by methods like spot welding or friction stir welding often have gaps outside the weld points, making them susceptible to corrosion due to moisture accumulation, and existing solutions either react with the materials at high temperatures or require additional filling materials.
Innovation Solution
The method involves using friction stir welding with multiple parallel weld seams that overlap without gaps, and an auxiliary tool to press material into a recess, sealing the parting line between components, eliminating the need for additional materials and ensuring a gap-free connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spot welding or friction stir welding is used to join lap joints, then welding strength is achieved, but connecting gaps remain between components outside the weld points which are susceptible to corrosion
Solution Approach 1:
A filling material is introduced as an intermediary substance between the overlapping components to seal the connecting gaps. This filling material prevents moisture penetration and eliminates corrosion-prone gaps while maintaining the structural integrity provided by the weld points.
Solution Approach 2:
The welding process and gap-filling operations are combined into a single integrated process. The filling material is applied during the welding process itself, merging the strength-providing welding function with the corrosion-protection gap-sealing function into one unified operation.
2Reliability
If additional filling materials are inserted between components to eliminate gaps, then corrosion resistance is improved, but the filling materials react with material in the welding zone at high temperatures and change material properties
Solution Approach 1:
The temperature parameters of the welding process are controlled and adjusted to remain below the reaction threshold of the filling material. By changing the thermal parameters, the filling material maintains its stability and does not react with the base materials, preserving both corrosion resistance and material property integrity.
3Reliability
If multiple parallel weld seams are formed to eliminate gaps, then corrosion resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The welding process is segmented into multiple parallel weld seams that are formed sequentially or simultaneously. This segmentation allows the welding system to target specific gap areas individually, eliminating corrosion-prone regions without requiring complete redesign of the welding apparatus.
Solution Approach 2:
The solution transitions from a single linear weld seam to multiple parallel weld seams, adding a dimensional aspect to the welding approach. This multi-dimensional welding strategy eliminates gaps more effectively while distributing the manufacturing complexity across multiple simpler, parallel 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 a lap butt welded joint with enhanced strength and corrosion resistance, as no gaps are left for moisture to accumulate, increasing the durability and eliminating the need for additional filling materials.
Implementation Method 1
a rotating welding tool is pressed against at least one of the components to generate frictional heat
Implementation Method 2
in which a rotating welding tool is pressed against at least one of the components to generate frictional heat
Implementation Method 3
an auxiliary tool is arranged during the welding process in such a way that one of the components is clamped between the auxiliary tool and the welding tool and both bases abut against the auxiliary tool. During friction stir welding, material from both bases is then pressed into a recess on the auxiliary tool
Data Source
Figure 1~2
Figure 3
AI summary
The present invention provides a method for producing overlap butt weld connections comprising the following process steps: providing two components to be joined, each having at least one base; arranging the components such that the bases face each other and the components overlap in an overlap area that extends at least partially over both bases; joining the components by welding in the overlap area, forming at least one weld seam, whereby unwelded areas are formed along the weld seam at the edge of the overlap area; removing the unwelded areas, thereby forming external cut surfaces on the components that are arranged at obtuse angles to the overlap area.