Laser-Welded Blank With Concave Weld End to Prevent Rupture
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Solution Overview
Problem
Existing methods for laser welding in patchwork blanks require complex irradiation control and often result in stress concentration at the terminal end of the weld zone, leading to potential rupture of the starting materials.
Innovation Solution
A method where two or more starting materials are joined by laser welding, with a single layer region and a multi-layer region, and the laser weld zone's terminal end is located at the end of the single layer region, forming a concave-shaped welding end portion, reducing stress concentration and preventing rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the terminal end of a laser weld zone is located within the starting material, then the welding process is simple, but stress concentration occurs due to the shape of the laser weld zone, causing the starting material to rupture
Solution Approach 1:
The laser welding process is divided into two distinct stages: a first laser welding stage that creates an initial weld zone, and a second laser welding stage that creates a terminal weld zone with a specific shape. This segmentation allows each stage to serve a specific function - the first stage provides simple joining while the second stage creates the stress-distributing shape that prevents rupture.
Solution Approach 2:
The first laser welding stage performs a preliminary welding action that creates an initial weld zone before the second stage. This preliminary action prepares the material structure so that when the second laser welding stage creates the terminal weld zone, the resulting shape effectively distributes stress and prevents rupture.
2Strength
If fine laser irradiation control is performed with gradual output decrease and rotational scan, then joint strength of laser weld zone is improved, but the welding process becomes complex
Solution Approach 1:
The complex laser irradiation control is segmented into two separate welding stages, each with its own controlled parameters. The first stage uses standard laser welding parameters for efficiency, while the second stage uses specific parameters to create the desired terminal weld zone shape. This segmentation achieves high joint strength without requiring continuously variable complex control.
Solution Approach 2:
The laser welding is performed in periodic discrete stages rather than as a continuous variable process. The laser beam is applied in distinct intervals - first for initial welding, then after a gap, for terminal weld zone formation. This periodic action simplifies control compared to continuous gradual output decrease while achieving similar or better results.
3Strength
If welding with high output laser beam and welding with low output laser beam are performed separately, then welding strength is improved, but it requires performing laser irradiation two times for the same position
Solution Approach 1:
The two separate welding operations (high output and low output laser irradiation) are merged into a single continuous laser welding process with two stages. The laser beam remains applied throughout both stages without being removed, eliminating the time loss associated with stopping and restarting the laser. The output is simply adjusted between stages while maintaining continuous irradiation.
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 simplifies the welding process and effectively suppresses rupture at the laser weld zone by distributing stress more evenly, enhancing the joint strength and reducing the likelihood of delayed fracture.
Implementation Method 1
the starting materials are joined with each other by moving a laser irradiation apparatus from an initial end to a terminal end with the laser irradiation apparatus emitting a laser beam
Implementation Method 2
two or more starting materials that overlap each other are joined with each other by laser welding
Implementation Method 3
when the laser beam reaches the welding terminal portion, a rotational scan is performed at the terminal portion about an axis extending in a thickness direction of the workpieces to cause a molten portion of molten metal to flow in a circular shape
Implementation Method 4
tensile stress generated at the time of the molten metal solidifying is equalized, thus preventing solidification cracking
Data Source
AI summary
There is provided a blank in which two or more starting materials that overlap each other are joined with each other by laser welding, including the blank has a single layer region, in which only one of the starting materials is present, and a multi-layer region, in which two or more of the starting materials overlap each other, laser welding is continuously applied to the multi-layer region and the single layer region, and one end of a laser weld zone is located at an end portion of the single layer region of the blank, and the one end forms a concave-shaped welding end portion having a concave shape when the blank is viewed from an end face.