What are the challenges in thin-wall welding?
Thin-walled corrugated pipes have minimal wall thickness and low rigidity, making them prone to burn-through, weld sagging, or tube deformation even with slight fluctuations in energy input per unit length during welding. 304 and 31 6L stainless steel exhibit relatively poor thermal conductivity and a high coefficient of linear expansion; if heat concentrates and dissipation is insufficient, localized temperature rise will further increase the risk of deformation.
Three Key Control Points
- Energy Control: Use relatively low laser power with high welding speed to ensure full penetration, and maintain continuous laser output to minimize spatter.
- Clamping and Heat Dissipation: Use tooling or mandrels that match the bellows profile to ensure precise positioning and enhance heat transfer, minimizing localized overheating.
- Gas protection: Optimize shielding gas flow rate and direction to minimize oxidation and plasma shielding effects on melt pool stability.
Trial Welding and Process Curing
Due to variations in material condition, corrugation dimensions, and joint configurations across batches, define the process window based on trial weld results: first, use parametric welding trials to verify penetration depth and weld width; then check for gas tightness and appearance; finally, program the parameters and record the corresponding specifications. For wall thicknesses below 0.3 mm or tightly spaced corrugations, conduct a process evaluation and pilot validation with the equipment manufacturer before proceeding to mass production.