How to solve the problem of color in laser welding seams

Reasons for the appearance of color in laser welding seams
During laser welding, if the welding parameters are not appropriate, it often leads to the appearance of color in the weld seam. This problem mainly occurs on high reflective materials such as stainless steel, aluminum alloys, and titanium alloys. After analysis, in addition to inappropriate welding parameters, the following factors may also cause discoloration of laser welding seams:
1. The laser welding head is not aligned with the welding position;
2. Excessive laser energy density can cause deformation or the formation of protrusions or depressions in the weld seam;
3. The discharge phenomena such as XE pulse arc generated during the welding process can damage the weld material;
4. Poor gas protection causes oxidation of the welded parts;
5. When laser welding, the light beam bends or twists;
6. The material surface is dirty or not cleaned thoroughly.

How to solve the problem of color in laser welding seams
1. Reasonably set welding parameters
To avoid color changes in solder joints, appropriate welding parameters must be set. This requires adjusting welding parameters based on factors such as the type, thickness, and introduced laser power of the welding material. Generally speaking, if the laser power is too high, there is a risk of welding paint peeling or oxidation due to deformation of the solder joint and large beam spot. If the laser power is too low, defects such as porosity in the weld seam will increase, which is not conducive to improving the welding quality.

2. Choose appropriate welding materials
In addition to appropriate welding parameters, selecting the appropriate welding material is also an important factor in avoiding discoloration of the welding point. Welding materials must meet the characteristics of high reflection, high thermal conductivity, etc., and be able to effectively resist the deformation and deformation generated during the welding process.

3. Maintain appropriate gas protection
Good gas protection is the key to keeping the weld colorless. During the welding process of high reflective materials, the solder joints are prone to oxidation, resulting in color. Using high-quality gas protection, such as high-purity argon, can reduce oxidation and improve welding quality.

4. The influence of light source on weld seam
The influence of laser on welding materials is one of the important factors in the welding process. If the laser beam is focused on the welding surface due to bending or twisting, it will cause discoloration of the welding point. Regularly check the laser path to ensure that the laser beam is working properly.

5. Cleaning work
Before performing welding operations, it is necessary to ensure that the welding surface has been thoroughly cleaned. Unclean surfaces may have residual grease, moisture, or other chemicals that can affect solder joints. By using appropriate cleaning methods such as solution cleaning or electrostatic cleaning, this situation can be effectively avoided.