Stainless steel laser welding is a high-precision and efficient process with minimal heat-affected zones and strong penetration capabilities. It is highly adaptable, suitable for various thicknesses and complex shapes. Key points include optimizing parameters like laser power and pulse width, pre-treating materials, and controlling the welding process. The equipment used includes fiber laser welding machines, continuous laser welding machines, and laser welding robots. The process is ideal for applications requiring high-quality, durable welds with minimal distortion.

Stainless Steel Laser Welding Process and Equipment

I. Technical Process Features

1. High Precision and Efficiency: Laser welding uses a highly focused laser beam with extremely high energy density, enabling high-precision and high-speed welding. For example, when welding a 1.0 mm thick 304 stainless steel sheet with a fiber laser, a welding speed of 12 mm/s can be achieved.
2. Small Heat-Affected Zone (HAZ): The heat input during laser welding is minimal, significantly reducing material deformation and the HAZ, which helps maintain the corrosion resistance of stainless steel.
3. Strong Penetration Capability: Laser welding can achieve deep penetration, forming a strong weld. For example, with a laser power of 1400 W, a penetration rate of 85% can be achieved for a 3.0 mm thick stainless steel plate.
4. High Adaptability: Laser welding can accommodate different thicknesses and compositions of stainless steel, and it can also be used for joining dissimilar materials as well as welding complex shapes and hard-to-reach areas.
5. Non-Contact Welding: Laser welding is a non-contact process, which allows welding of hard-to-reach areas and offers great flexibility.

II. Key Technical Process Points

1. Process Parameter Optimization: The key to laser welding is the precise adjustment of process parameters, such as laser power, pulse width, and defocus amount. For example, for a 1.0 mm thick 304 stainless steel plate, a peak power of 3000 W, a pulse width of 6 ms, and a defocus amount of 2 mm can produce the best welding joint.
2. Material Pre-treatment: Before welding, the stainless steel surface should be cleaned, such as with alcohol, to remove oil and impurities to ensure welding quality.
3. Welding Process Control: During welding, the focus, oscillation frequency, and oscillation length of the laser beam should be strictly controlled to ensure the uniformity and consistency of the weld.
4. Post-Weld Treatment: After welding, the weld should be inspected and cleaned, and heat treatment should be performed if necessary to eliminate welding stress.

III. Equipment

1. Fiber Laser Welding Machine: Suitable for small-sized, high-precision welding tasks, such as stainless steel jewelry and precision components. Its features include concentrated energy, fast welding speed, and a small HAZ.
2. Continuous Laser Welding Machine: Often used for thick plate welding, it has high welding efficiency and strong penetration capability.
3. Laser Welding Robot: It can carry laser welding equipment to achieve automated welding, improving production efficiency and welding quality.
4. Auxiliary Equipment: Including optical microscopes, electron backscatter diffraction instruments, universal material testing machines, etc., for weld quality inspection and analysis.

IV. Technical Parameter Table

Selection and Matching of Lasers for Stainless Steel Welding

In stainless steel welding, the selection of appropriate lasers and their matching equipment is crucial. Here are some recommendations:

Selection of Lasers for Stainless Steel Welding

• Based on Material Thickness:
  • Thin Stainless Steel (less than 3 mm): Fiber lasers and diode lasers are ideal choices. Fiber lasers offer high beam quality and stable output, suitable for high-precision welding, while diode lasers have certain advantages in welding speed and weld strength.
  • Medium to Thick Stainless Steel: High-power continuous fiber lasers can be selected. For example, when welding 304 stainless steel with a 3000W laser, the maximum penetration depth can reach 5 mm.
• Beam Quality: Good beam quality can improve welding accuracy, reduce welding defects, and ensure weld quality and strength.
• Pulse Duration: Short pulses are suitable for thin materials, while long pulses are suitable for thick materials.
• Other Factors: The stability of laser power output, service life, and maintenance costs should also be considered.

Matching of Lasers for Stainless Steel Welding

• Welding Equipment:
  • Pulsed Laser Welding Machine: Suitable for small-sized, high-precision welding tasks, such as stainless steel jewelry and precision components.
  • Continuous Laser Welding Machine: Often used for welding large stainless steel structural components, with fast welding speed and high efficiency.
  • Laser Welding Robot: It can carry laser welding equipment to achieve automated welding, improving production efficiency and welding quality.
• Auxiliary Equipment: Including optical microscopes, electron backscatter diffraction instruments, universal material testing machines, etc., for weld quality inspection and analysis.
• Beam Delivery System: Ensures that the laser energy is stably and accurately applied to the welding area.
• Shielding Gas System: Such as argon gas, which can prevent oxidation of the weld and improve welding quality.