Laser Lap Welding of Plated Plates With Beam Sweeping
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Solution Overview
Problem
Lap welding of plating plate materials often results in welding defects due to the evaporation of plating layers, which disturbs the molten pool and leads to underfill and surface irregularities, especially when the plating layer's boiling point is lower than the metal's melting point.
Innovation Solution
A welding method and apparatus that utilize a processing laser beam with a power distribution shape featuring multiple power regions along a predetermined direction, allowing for relative movement between the laser beam and workpiece, effectively sweeping the beam to create a deepened molten pool, thereby reducing gas disturbance and improving surface flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a protrusion is formed on a plated steel plate to enable welding, then welding can be performed, but an additional process step is required
Solution Approach 1:
The invention extracts and removes the plating layer from the welding area to eliminate the harmful effect of gas evolution during welding, thereby avoiding the need for additional protrusion formation processes while maintaining welding quality
Solution Approach 2:
The plating layer is removed in advance from the welding area before welding begins, preventing gas evolution issues during the welding process and eliminating the need for subsequent protrusion formation steps
2Stability of the object's composition
If the plating layer is present during laser welding, then the plated steel plate structure is maintained, but the plating layer evaporates and disturbs the molten pool causing welding defects
Solution Approach 1:
The plating layer is extracted and removed from the welding area to eliminate the source of gas evolution that disturbs the molten pool, thereby preventing welding defects while preserving the plated structure in non-welding areas
Solution Approach 2:
The plating layer is selectively removed only from the specific welding area while maintaining the plated structure in other areas, achieving local modification to prevent welding defects without compromising the overall plated steel plate structure
3Stability of the object's composition
If the plating layer evaporates during welding, then the plated steel plate structure is maintained, but gas pressure blows off molten liquid causing underfill
Solution Approach 1:
The plating layer is removed from the welding area to eliminate gas evolution that would blow off molten liquid and cause underfill, thereby ensuring adequate welding strength while maintaining the plated structure elsewhere
Solution Approach 2:
The plating layer is removed in advance from the welding area to prevent gas pressure from blowing off molten liquid during welding, ensuring proper weld formation and strength
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
The method suppresses welding defects by ensuring gradual gas discharge and maintaining molten pool surface area, preventing underfill and surface irregularities, and enhancing welding strength and efficiency.
Implementation Method 1
a welding method in which a welding area of the workpiece is irradiated with a laser beam and the welding area is melted by the energy of the laser beam
Implementation Method 2
the welding area is melted by the energy of the laser beam
Implementation Method 3
the plating layer evaporates to become a gas when the steel material melts
Data Source
AI summary
A welding method includes: layering two or more plate materials each including a plating plate material having a preform on a surface of which a plating layer is formed to form a workpiece; disposing the workpiece in a region to be irradiated with a processing laser beam; generating the processing laser beam having a power distribution shape in which two or more power regions are disposed along a predetermined direction in a plane perpendicular to a light traveling direction; irradiating a surface of the workpiece with the processing laser beam; and moving the processing laser beam and the workpiece relatively while performing the irradiation, and melting an irradiated area of the workpiece to perform welding while sweeping the processing laser beam in the predetermined direction on the workpiece during a swing of the processing laser beam.