Oscillating Laser Welding of Coated Steel Flange Joints
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Solution Overview
Problem
Laser welding of metal components with metallic coatings, such as zinc or AlSi, often results in zinc degassing, increased porosity, and the formation of brittle intermetallic phases due to melting temperature differences, leading to welds that fail to meet strength requirements, especially under dynamic stress.
Innovation Solution
A high-frequency oscillation of the laser welding beam between 80 Hz and 1000 Hz, primarily in a sine shape, keeps the weld pool liquid longer and introduces dynamic energy to facilitate controlled degassing and distribution of metallic phases, preventing the accumulation of intermetallic phases and reducing splatters, while maintaining a homogeneous weld seam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser welding is used on coated steel components, then welding speed and productivity are maintained, but zinc degassing, porosity, and brittle intermetallic phases occur reducing weld strength
Solution Approach 1:
The patent applies dynamic oscillation of the laser beam at frequencies between 80 Hz and 1000 Hz to maintain the weld pool in a liquid state longer, enabling controlled degassing and phase distribution while maintaining high welding speeds. This dynamic approach prevents the formation of brittle intermetallic phases and reduces porosity, thereby achieving both high productivity and weld strength.
Solution Approach 2:
The patent utilizes mechanical vibration through high-frequency oscillation of the laser beam to create controlled turbulence in the weld pool. This vibration promotes gas escape and uniform distribution of metallic phases, preventing defect formation while maintaining efficient welding processes, thus resolving the contradiction between welding speed and weld quality.
2Manufacturing precision
If high energy is applied to weld through coated materials, then welding depth is increased, but coating evaporation and splatter formation increase
Solution Approach 1:
The patent employs periodic oscillation of the laser beam at controlled frequencies to modulate energy input. This periodic action creates cycles of melting and slight resolidification that facilitate controlled vaporization of the coating, allowing gases to escape in a controlled manner rather than causing explosive evaporation. The result is reduced splatter while maintaining adequate weld penetration.
3Manufacturing precision
If laser beam dwell time is extended in edge regions to increase energy introduction, then weld depth is improved, but heat-affected zone and distortion increase
Solution Approach 1:
The patent uses dynamic laser beam oscillation to distribute energy more uniformly across the weld zone. The oscillating beam continuously moves between edge and center regions, preventing excessive heat accumulation in any single area while ensuring adequate energy input for proper penetration. This dynamic energy distribution achieves weld depth without excessive heat-affected zone or distortion.
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 produces pore-free welds with enhanced strength properties, accommodating thickness variations and ensuring the weld seam reflects the actual connection depth, suitable for high-strength steel components with minimal weight reduction and reduced labor in coating applications.
Implementation Method 1
the laser welding beam is moved back and forth in an oscillating manner transversely to the advancement direction
Implementation Method 2
the oscillation of the laser welding beam takes place at a frequency between 80 Hz and 1000 Hz
Implementation Method 3
the weld pool that forms due to the introduction of energy during laser welding is kept liquid for the controlled occurrence of degassing processes
Implementation Method 4
introduces dynamic energy to facilitate controlled degassing and distribution of metallic phases
Data Source
AI summary
The invention relates to a method for laser welding the end faces of the joints (5, 6) of two connecting flanges (3, 4), which are held in an adjoining manner, of two connecting partners (1, 2) made of a steel material. According to the method, in addition to being moved in the advancement direction, which follows the longitudinal extension of the joints (5, 6), the welding laser beam (8) is moved back and forth in an oscillating manner transversely to the advancement direction. At least one of the two connecting partners (1, 2) to be welded at the connecting flange (3, 4) joints (5, 6) is equipped with a metal coating at least in the region of the respective connecting flange (3, 4). The weld pool produced by the energy input during the laser welding process is kept in a liquid state in order to allow degassing processes and/or distribution processes to be carried out in a controlled manner for phases of the metal coating of the at least one connecting partner, said metal coating being integrated by the welding process, wherein the welding laser beam is oscillated at a frequency of at least 80 Hz.