Overlap Sheet Welding Wire Penetration for Dissimilar Metals
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Solution Overview
Problem
Existing welding methods for overlapping metal sheets, particularly those with dissimilar materials, often result in brittle phases and limited miscibility, leading to undesirable material connections and requiring additional degassing steps, which complicates the joining process.
Innovation Solution
A method using a fusible welding wire in wire or strip form, melted by an electric arc, penetrates overlapping metal sheets to create a trough-shaped pool of molten weld metal that is then pressed onto the lower sheet, controlling wire feed speed to achieve a narrow metallurgical interaction zone and prevent extensive alloy formation, effectively combining material and form-fitting connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding methods are used to join overlapping metal sheets, then a material connection is achieved, but brittle phases and undesirable alloys form when joining dissimilar materials
Solution Approach 1:
The welding process is segmented into distinct phases: initial arc ignition to melt the upper sheet, wire penetration through the molten pool, and controlled pressing of the wire into the lower sheet. This segmentation allows precise control over metallurgical interactions at each stage, preventing excessive alloy formation and brittle phase development while maintaining joint strength.
Solution Approach 2:
The invention dynamically changes critical parameters during welding: wire feed speed is adjusted to control penetration depth, arc energy is modulated to maintain appropriate pool size, and pressing force is controlled to limit metallurgical interaction zone width. These parameter changes enable the formation of a narrow interaction zone that prevents undesirable alloy formation while ensuring adequate joint strength.
2Reliability
If additional process steps are added to prevent brittle phase formation, then material quality improves, but process complexity increases
Solution Approach 1:
The invention merges multiple functions into a single integrated welding process: the arc provides both heating and melting, the wire serves as both filler material and penetration tool, and the pressing action simultaneously fills the joint and controls metallurgical interaction. This consolidation eliminates the need for separate degassing steps or additional process operations, maintaining material quality while simplifying the overall process.
Solution Approach 2:
The welding process rapidly progresses through the critical phase where brittle phases could form by quickly penetrating the wire through the molten pool and pressing it into the lower sheet. This rapid execution minimizes the time window for undesirable alloy formation, achieving high material quality without requiring additional slow process steps for degassing or treatment.
3Productivity
If wire feed speed is increased to improve productivity, then welding speed increases, but control over metallurgical interaction zone precision decreases
Solution Approach 1:
The wire feed speed is made dynamic rather than static, being adjusted in real-time based on process conditions. The system transitions from steady-state feeding to accelerated feeding during penetration, then to controlled feeding during joint filling. This dynamic adjustment maintains precision of the metallurgical interaction zone while maximizing overall welding productivity.
Solution Approach 2:
The welding process employs periodic variations in wire feed speed and arc energy during different stages: initial melting phase, penetration phase, and filling phase. These periodic adjustments ensure precise control over the metallurgical interaction zone during critical moments while maintaining high average productivity throughout the complete welding cycle.
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 prevents the formation of brittle phases, allows for efficient joining of dissimilar materials with minimal heat input and distortion, and produces a fail-safe spot weld connection with reduced material incompatibility issues, suitable for safety-relevant applications and various material combinations.
Implementation Method 1
using an electric arc as the energy source for melting the metal sheets and welding wire
Implementation Method 2
the metal sheets and welding wire are melted, forming a pool of molten weld metal
Implementation Method 3
The welding wire is then pressed into the overlapping area of the metal sheets and penetrates the metal sheets in the area of a predetermined joint
Data Source
Figure 1~2
AI summary
The invention relates to a welding method and a welding device for connecting overlapping metal sheets, the top metal sheet (1) of the overlapping metal sheets first being melted with an arc (6) between a continuously fed welding wire (3) and the top metal sheet (1), and then the overlapping metal sheets be penetrated by means of the welding wire (3). With the method according to the invention, a positive and material-locking spot weld is created. The ability to use off-the-shelf, widely available and inexpensive welding jigs ensures cost-effective and time-saving welding. The method is particularly advantageous for connecting dissimilar materials, since the short welding times according to the invention prevent unfavorable metallurgical interactions.