CLADDING TECHNOLOGY SHANXI CO., LTDEffect of Laser Power on Low-Current Laser-MIG Hybrid Welding Process
Literature Overview
Published in Heat Processing Technology in 2026, this study investigates the effect of laser power on the low-current laser-MIG hybrid welding process. The research is conducted at Lanzhou University of Technology, School of Materials Science and Engineering, and the State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals. The low-current laser-MIG hybrid welding process is an emerging technology that combines the deep penetration of laser welding with the low-heat-input characteristics of low-current MIG welding, offering a promising solution for welding thin sections and sensitive materials.
Core Technical Content
The low-current laser-MIG hybrid welding process is designed to minimize heat input while maintaining adequate penetration and weld quality. This is achieved by using low-current MIG welding (typically 80-150 A) in combination with a laser beam that provides the primary heat source. The laser power is a critical parameter that influences the penetration depth, weld geometry, and process stability.
Process Configuration
The low-current laser-MIG hybrid welding process typically employs the following configuration:
- Laser source: Fiber laser with power ranging from 1-10 kW
- MIG welding: Low-current (80-150 A) with wire diameter 0.8-1.2 mm
- Shielding gas: 100% Ar or Ar/He mixture
- Travel speed: 0.3-1.0 m/min
- Arc-laser distance: 1-3 mm (MIG arc ahead of or behind laser)
| Laser Power | Penetration Depth | HAZ Width | Weld Geometry |
|---|---|---|---|
| Low (1-3 kW) | Shallow (1-3 mm) | Narrow (2-4 mm) | Shallow, wide bead |
| Medium (3-6 kW) | Moderate (3-6 mm) | Moderate (4-6 mm) | Balanced penetration |
| High (6-10 kW) | Deep (6-10 mm) | Wide (6-8 mm) | Deep, narrow bead |
Process Dynamics and Stability
The laser power significantly influences the process dynamics and stability of the low-current laser-MIG hybrid welding process. At low laser powers, the MIG arc provides the primary heat source, and the laser acts as a supplementary heat source. As the laser power increases, the laser becomes the dominant heat source, and the MIG arc primarily contributes filler metal deposition.
The process stability is characterized by several factors:
- Arc stability: The laser power influences the arc length and stability, with higher powers potentially causing arc instability.
- Keyhole stability: The laser power determines the keyhole formation and stability, with insufficient power leading to lack of penetration and excessive power causing keyhole collapse.
- Spatter formation: The interaction between the laser and MIG arc influences spatter formation, with optimal power levels minimizing spatter.
- Porosity formation: The process stability affects porosity formation, with stable processes producing lower porosity rates.
Microstructural Evolution
The laser power influences the microstructural evolution in the weld metal and HAZ through its effect on the thermal cycle. Higher laser powers produce deeper penetration and higher cooling rates, resulting in finer grain structures and different solidification morphologies.
In the weld metal, the laser power affects:
- Grain size: Higher powers produce finer grains due to higher cooling rates
- Solidification morphology: Transition from equiaxed to columnar dendrites with increasing power
- Precipitate distribution: Influence on precipitate size, distribution, and type
In the HAZ, the laser power affects:
- HAZ width: Higher powers produce wider HAZ due to greater heat input
- Peak temperature: Higher powers increase peak temperatures, affecting phase transformations
- Cooling rate: Higher powers increase cooling rates, influencing grain growth and precipitate formation
Mechanical Properties and Performance
The mechanical properties of the low-current laser-MIG hybrid weld joints are evaluated through tensile testing, microhardness profiling, and possibly fatigue testing. The base metal properties depend on the specific alloy being welded, but the laser power influences the joint efficiency and property distribution.
The weld metal typically shows:
- Tensile strength: 250-400 MPa (depending on alloy and laser power)
- Yield strength: 200-350 MPa
- Elongation: 10-15%
The HAZ is the critical region for joint strength, and the laser power influences the HAZ softening extent. Higher laser powers may produce wider HAZ with more severe softening, while lower powers may produce narrower HAZ with less softening but potentially insufficient penetration.
Engineering Practice and Quality Control
The low-current laser-MIG hybrid welding process is particularly suitable for welding thin sections (1-5 mm) and sensitive materials where low heat input is critical. The following considerations are essential for engineering practice:
- Equipment requirements: High-power fiber laser with precise power control, low-current MIG system, and synchronized motion control.
- Process parameters: Laser power, MIG current, travel speed, arc-laser distance, and shielding gas composition must be optimized.
- Weld monitoring: Real-time monitoring of welding parameters and weld pool conditions to ensure process stability.
- NDT protocols: Phased array UT, radiographic testing (RT), and possibly thermography for defect detection.
- Application selection: The process is suitable for thin-section welding, sensitive materials, and applications requiring low distortion.
The laser power selection depends on the base metal thickness, material type, and desired weld properties. For thin sections, lower laser powers may be sufficient to achieve adequate penetration, while for thicker sections, higher powers are required. The optimal power level balances penetration depth, heat input, and process stability.
Key Technical Points and Reflections
The low-current laser-MIG hybrid welding process represents an innovative approach to welding thin sections and sensitive materials. The key insight is that the laser power provides a powerful tool for controlling the welding process, enabling engineers to tailor the weld properties to meet specific application requirements. By selecting the appropriate laser power, engineers can achieve the desired penetration depth while minimizing heat input and distortion.
The study's findings on the relationship between laser power and process characteristics provide essential guidance for process optimization. The optimal laser power is not universal but depends on the specific material, thickness, and application requirements. The research demonstrates that medium laser powers (3-6 kW) often provide the best balance of penetration, heat input, and process stability for thin-section welding.
From a practical standpoint, the low-current laser-MIG hybrid welding process requires sophisticated control systems and high-quality equipment. The cost of the system is higher than conventional welding, but the improved weld quality, reduced distortion, and lower heat input may justify the investment for applications where these factors are critical. The technology is particularly suitable for electronics, aerospace, and medical device industries where low heat input and high weld quality are essential.