Welded Steel Blank Edge Ablation for Low-Aluminum Laser Welding
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Solution Overview
Problem
Existing methods for preparing aluminized steel sheets for welding face challenges such as aluminum dilution during the welding process, leading to reduced mechanical strength and toughness of the welded joints, and difficulties in accurately guiding the laser beam due to the darker appearance of sheets with removed metal alloy layers, resulting in less accurate seam tracking.
Innovation Solution
A method involving the simultaneous removal of the metal alloy layer by melting and vaporization on the principal faces of steel sheets, leaving the intermetallic alloy layer in place, with a controlled gap between the sheets to prevent aluminum flow and improve seam tracking accuracy, using a laser beam to remove the metal alloy layers in a peripheral zone, and subsequent welding along a defined median plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the metal alloy layer is removed by melting and vaporization to reduce aluminum content in the welded joint, then the mechanical strength of the welded joint is improved, but the seam tracking accuracy deteriorates due to the darker appearance of the treated surface
Solution Approach 1:
The patent applies preliminary action by performing the metal alloy layer removal (ablation) before the welding operation. The laser beam removes the aluminum-rich metal alloy layer from the sheet edges, creating a clean surface for welding. This preliminary preparation ensures that when welding occurs, the aluminum dilution is minimized, maintaining the mechanical strength of the welded joint while allowing the welding process to proceed on a pre-prepared surface.
2Quantity of substance
If a gap is introduced between the sheets during ablation to prevent aluminum flow, then the purity of the welded joint is improved, but the device complexity increases due to the need for precise positioning and control
Solution Approach 1:
The patent applies parameter changes by controlling the gap distance between the sheets during the ablation process. By optimizing this geometric parameter, the method prevents aluminum flow from one sheet to another while maintaining a simple processing setup. The gap is controlled to be within a specific range (0.02-2mm) to achieve the desired effect of minimizing aluminum content in the welded joint without requiring complex positioning systems.
3Productivity
If the ablation and welding operations are performed in immediate succession to minimize oxidation, then the productivity is improved, but the manufacturing precision may deteriorate due to thermal effects on the sheet material
Solution Approach 1:
The patent applies continuity of useful action by performing the welding operation immediately after the ablation process without intermediate steps or delays. This continuous workflow minimizes the exposure time of the freshly ablated surface to oxidation, ensuring high purity of the welded joint. The laser beam transitions directly from ablation mode to welding mode, maintaining process efficiency and productivity while controlling thermal effects through precise parameter management.
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 effectively reduces aluminum content in the welded joint to less than 0.3%, enhances the accuracy of seam tracking, and maintains the mechanical properties of the base metal, resulting in stronger and more reliable welded joints with improved productivity by minimizing oxidation and allowing for immediate welding after ablation.
Implementation Method 1
by melting and vaporization simultaneously on the principal faces (111, 121), the layer of metal alloy (19, 20) is removed
Implementation Method 2
by melting and vaporization simultaneously on the principal faces (111, 121), the layer of metal alloy (19, 20) is removed
Implementation Method 3
a welding operation of the first sheet (11) and second sheet (12) is carried out by melting, by at least one laser beam (95), in the zone from which the layer of metal alloy (19, 20) has been removed
Data Source
AI summary
A method for the preparation of steel sheets for fabricating a welded steel blank is provided. The method includes a step of removing at least part of the first and second metal alloy layers in first and second peripheral zones of pre-coated steel first and second sheets, respectively, by simultaneously ablating the first and second precoatings in the first and second peripheral zones of the pre-coated steel first and second sheets to define first and second ablation zones, the first and second peripheral zones being zones of the first and second principal faces closest to the median plane and located on either side of the median plane.