Experimental and Numerical Studies of Laser-Welded Slender Stainless Steel I-section Columns

Stainless steel has extensive applications in the construction industry because of its attractive appearance, unique corrosion resistance, durability, and superior mechanical properties. Laser-welding is a manufacturing process that is suitable for connecting various steel and stainless steel. High precision and low heat input characteristics make it have smaller heat-affected zones than the traditional welding process, resulting in lower thermal distortions and residual stress to give it increased load-carrying capacity. The present paper focuses on investigating the structural response of laser-welded slender stainless steel I-section columns to address the lack of test data. Nine stub columns tests and ten long columns tests were analysed for slender I-sections of austenitic laser-welded stainless steel of two stainless steel alloys (austenitic EN 1.4301 and EN 1.4307). Additionally, the material tensile coupon tests, residual stress measurements, and initial geometric imperfection measurements were performed. The observed results verified a representative residual stress pattern. The finite element model was validated based on the test results and parametric analysis was carried out on laser-welded slender stainless steel I-section axially compressed members. Further, the study evaluated the cross-sectional and column buckling resistances for European code EN 1993-1-4, American Design Guide AISC 27, and Continuous Strength Method. Interestingly, the continuous strength method reflected significantly better buckling behaviour of slender I-sections. Although this method gives more accurate results than the code predictions, slight conservatism predictions were still found for slender I-section columns with room for improvement.