Laser Welding Of Stainless Steel: A Comprehensive Analysis Of Deformation Issues

In the industrial manufacturing sector, stainless steel is widely used across various industries such as food, healthcare, and construction due to its excellent corrosion resistance, high strength, and aesthetic appeal. As an advanced welding device, the laser welder offers advantages such as high precision and efficiency, making it a popular choice for stainless steel welding. However, does laser welding of stainless steel cause deformation?
From a theoretical perspective, laser welders inherently have the advantage of minimizing deformation. They utilise high-energy-density laser beams as a heat source, instantly melting the stainless steel locally to form a weld. Compared to traditional welding methods, laser welding has extremely low heat input, with rapid heating and cooling rates. The heat-affected zone is typically controlled within an extremely small range, generally only a few tenths of a millimetre. This results in relatively low thermal stress on the material during welding, theoretically reducing the likelihood of deformation.
However, deformation issues may still arise during actual welding. When stainless steel is welded, localized heating causes expansion, while surrounding areas that are not heated or have lower temperatures constrain this expansion, thereby generating thermal stress within the material. Upon welding completion and temperature reduction, material contraction occurs. If thermal stress cannot be released, deformation may result, commonly manifesting as wave deformation or angular deformation. Numerous factors influence deformation. In terms of material properties, different grades of stainless steel have varying physical properties such as thermal expansion coefficients and thermal conductivity. Thicker plates absorb more heat, increasing the likelihood of deformation. Welding process parameters are also critical. Excessive laser power or slow welding speed can cause heat to concentrate excessively, increasing the risk of deformation. Additionally, the assembly accuracy of the workpiece and the design and use of fixtures should not be overlooked. Large assembly gaps, severe misalignment, or poorly secured fixtures can generate additional stress during welding, exacerbating deformation. However, deformation can be controlled through various strategies. Precisely adjusting process parameters to determine the optimal combination based on material and workpiece conditions; optimising workpiece assembly to ensure alignment accuracy; designing reasonable fixtures to provide stable constraints; and employing preheating or post-heat treatment methods can reduce thermal stress and residual stress. Although deformation is possible when laser welding stainless steel, it can be controlled within acceptable limits through scientific measures to meet high-quality welding requirements.