Laser welding is a new welding method that utilizes high-energy laser pulses to locally heat materials in a small area. The energy from the laser radiation diffuses into the material through heat conduction, causing the material to melt and form a specific molten pool.

Advantages of Laser Welding

1. Minimizes heat input, resulting in a small range of metallurgical changes in the heat-affected zone and minimal deformation caused by heat conduction.

2. Validated process parameters for single-pass welding of 32mm thick plates can reduce the time required for thick plate welding and even save on filler metal usage.

3. No need for electrodes, eliminating concerns about electrode contamination or damage. As it is a non-contact welding process, it minimizes machine tool wear and deformation.

4. The laser beam is easily focused, aligned, and guided by optical instruments. It can be placed at an appropriate distance from the workpiece and redirected around machinery or obstacles near the workpiece. Other welding methods are limited in this regard.

5. Workpieces can be placed in enclosed spaces (vacuum or controlled internal gas environments).

6. The laser beam can be focused on a small area, allowing for the welding of small and tightly spaced components.

7. Wide range of weldable materials, including various heterogeneous materials that can be joined together.

8. Easily automated for high-speed welding and can be controlled digitally or by computer.

9. No issues with arc re-melting when welding thin wires or fine lines.

10. Unaffected by magnetic fields (unlike arc welding and electron beam welding), ensuring accurate alignment of weldments.

11. Capable of welding two metals with different physical properties (e.g., different electrical resistances).

12. No need for vacuum or X-ray protection.

13. With keyhole welding, the depth-to-width ratio of the weld bead can reach 10:1.

14. The setup can switch the laser beam to multiple workstations.

Disadvantages of Laser Welding

1. The position of the weldment must be highly precise and within the focal range of the laser beam.

2. When fixtures are required for weldments, the final position must align precisely with the spot where the laser beam will strike.

3. The maximum weldable thickness is limited. Laser welding is not suitable for production lines for workpieces with penetration depths exceeding 19mm.

4. For materials with high reflectivity and thermal conductivity, such as aluminum, copper, and their alloys, laser welding can alter their weldability.

5. Medium to high-energy laser beam welding requires plasma controllers to remove ionized gases around the molten pool, ensuring weld reproducibility.

6. Low energy conversion efficiency, typically below 10%.

7. Rapid solidification of the weld bead may lead to porosity and embrittlement issues.

8. Expensive equipment.

To eliminate or reduce the defects of laser welding and better apply this excellent welding method, several hybrid welding processes combining laser with other heat sources have been proposed. These include laser-arc hybrid welding, laser-plasma arc hybrid welding, laser-induction heat source hybrid welding, dual-laser beam welding, and multi-beam laser welding. Additionally, various auxiliary process measures have been introduced, such as laser wire feeding welding (which can be further divided into cold wire and hot wire welding), magnetic field-assisted enhanced laser welding, shielding gas-controlled molten pool depth laser welding, and laser-assisted friction stir welding.