How to improve the quality of aluminum alloy laser welding

1. Common consequences of poor welding quality

-Decreased welding strength: Poor quality welds often have defects such as cracks, pores, and lack of fusion, which lead to a decrease in the strength of the welded joint and make it unable to withstand external loads, thereby affecting the overall safety and reliability of the product.

-Reduced fatigue life: Joints with poor welding quality are prone to crack propagation under repeated loads, significantly reducing the fatigue life of the material.

-Poor corrosion performance: Uneven heat input during the welding process may lead to local overheating or rapid cooling, affecting the microstructure and corrosion resistance of the weld seam, thereby reducing the corrosion resistance of the aluminum alloy.
It is crucial to understand the influencing factors of each link in the welding process in order to ensure the quality of aluminum alloy laser welding.

2. The influence of incident angle on welding quality

During the laser welding process, the incident angle of the laser beam is one of the key factors affecting the welding quality. Different incident angles will have different effects on the formation of welds, the generation of defects, and the mechanical properties of welded joints.

-Welding seam formation
Small incidence angle: The contact area between the laser beam and the welding surface is small, and the heat input is concentrated, which may cause local overheating, resulting in irregular weld formation and uneven melt pool, which is prone to insufficient fusion or excessive melting.
Large incidence angle: A larger incidence angle increases the contact area between the laser beam and the welding surface, resulting in a more uniform heat distribution and facilitating the smooth formation of the weld seam. However, excessive incident angle may lead to insufficient depth of the molten pool, affecting the fusion effect of the weld and reducing the welding strength.

-Welding defects
Small incidence angle: The laser beam is too concentrated, and the temperature gradient in the welding area changes dramatically, which can easily form defects such as pores, cracks, and slag inclusions. In addition, due to the instability of the molten pool, gas release in aluminum alloys may be limited, further increasing the risk of porosity.

Large incidence angle: A larger incidence angle may cause the laser beam to tilt, resulting in uneven surface tension of the melt pool and increasing the risk of porosity. Meanwhile, the deviation of the laser beam may also cause welding position deviation, affecting the integrity of the weld seam.

-Mechanical properties of welded joints
Small incidence angle: Local overheating and uneven molten pool morphology caused by small incidence angle can result in coarse metallographic structure of the welded joint and reduce the strength of the weld zone. The softening phenomenon in the heat affected zone can also affect the tensile strength and fatigue strength of materials.

Large incidence angle: Although a larger incidence angle helps improve the formation of the weld seam, an excessively large angle may result in insufficient depth of the molten pool, affecting the strength of the weld seam and ultimately affecting the overall mechanical properties of the welded joint.

3.How to optimize the quality of aluminum alloy laser welding?

Reasonably selecting and adjusting the incident angle based on its impact on welding quality is the key to improving welding quality. Here are some optimization suggestions:

-Choose a moderate angle of incidence
Select the appropriate incident angle (usually between 15 ° and 30 °) based on the thickness of the welding material and the welding position. Within this range, the heat input of the laser beam is relatively uniform, which is beneficial for the smooth formation of the weld seam and reduces the risk of defects.

-Adjust welding parameters
In addition to the incident angle, factors such as welding laser power, welding speed, and spot size can also affect the welding quality. By adjusting these parameters appropriately based on changes in the incident angle, the negative impact of the incident angle can be compensated for, ensuring the stability and quality of the welded joint.

-Optimize welding trajectory
Adopting appropriate welding trajectories (such as rotating or swinging welding) can effectively alleviate the adverse effects caused by the incident angle. By optimizing the welding trajectory, the stability of the molten pool during the welding process is ensured, and the quality of the weld seam is improved.

The reasons for poor quality of aluminum alloy laser welding are usually related to various factors such as incident angle, welding parameters, and welding technology. By selecting the appropriate incident angle, adjusting welding parameters, and optimizing the welding trajectory, the welding quality can be significantly improved, and the problems of defects and performance degradation can be reduced. Mastering these techniques can not only improve the strength of welded joints, but also extend the service life of products, ensuring that aluminum alloy welded products meet high standard application requirements.