Welding Method for Uneven Thickness Members
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Solution Overview
Problem
Existing welding methods face challenges in achieving strong welds, particularly when joining metal members with significant thickness differences or complex surface geometries, such as curved or embossed surfaces, which can lead to uneven thermal capacity and stress concentration.
Innovation Solution
A welding method that involves forming a first bead on the thinner member with a curved or embossed surface, followed by arc welding to equalize thermal capacity and then welding this bead to a thicker member, creating a second bead with a larger cross-sectional area to enhance weld strength, often using a semi-automatic arc welder with a welding torch, feeder, and power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct welding is performed between metal members with significant thickness differences, then welding speed is maintained, but weld strength is insufficient due to uneven thermal capacity
Solution Approach 1:
The method applies preliminary action by forming a first bead on the thinner member before performing the final welding to the thicker member. This preliminary bead formation equalizes the thermal capacity between members of different thicknesses, creating optimal conditions for subsequent welding and ensuring high weld strength without sacrificing welding speed.
2Adaptability or versatility
If welding is performed on members with curved or embossed surfaces, then complex geometries are joined, but stress concentration occurs leading to reduced weld quality
Solution Approach 1:
The method applies local quality by forming a first bead that specifically addresses the complex surface geometry (curved or embossed) of the thinner member. This preliminary bead creation adapts to the local surface conditions and eliminates stress concentration points, thereby improving weld quality on complex geometries while maintaining the ability to join diverse shapes.
3Device complexity
If a single-pass welding method is used, then the process is simple, but weld strength is insufficient for thick members
Solution Approach 1:
The welding process is segmented into two distinct passes: a first pass that forms a bead on the thinner member to equalize thermal capacity, and a second pass that performs the final welding to the thicker member. This segmentation enables high weld strength by addressing thermal capacity differences systematically, while keeping each individual pass relatively simple and straightforward.
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 method reduces thermal capacity differences and increases weld strength, even across complex geometries, resulting in a more robust metal product suitable for applications like wheeled vehicles.
Implementation Method 1
arc welding (see, for example, Japanese Laid-Open Patent Publication No. 5-23856). Arc welding is a welding method which utilizes a discharge phenomenon (arc discharge) within a gas to join metal members together
Data Source
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Figure 3A~3C
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AI summary
A welding method that results in an enhanced strength is provided. A welding method according to an embodiment is a welding method for welding a first member 10 and a second member 20 together. The first member 10 has a smaller thickness than the thickness of the second member 20. A weldable portion of at least one of the first member 10 and second member 20 has at least one of a curved surface and an embossed surface. The welding method includes: a step of melting the first member 10 and a filler 106 to form a first bead 30 on the first member 10; and a step of melting the first bead 30, the second member 20, and the filler 106 to weld the first bead 30 to the second member 20.