In the field of steel structure welding, welding robot workstations have become the mainstream choice due to their high precision and stability. The core challenge lies in matching suitable welding processes to steel structures of different materials. Accurate matching directly determines weld quality, structural strength, and production efficiency, and is crucial for the successful implementation of robot welding without trial teaching.
Carbon steel is the most commonly used material in steel structures. When matching robot welding processes, gas metal arc welding (MIG/MAG) is the preferred choice, with a shielding gas mixture of 80% Ar + 20% CO₂ as the primary component. Regarding process parameters, the welding current should be controlled between 180-250A, the voltage between 22-28V, and the travel speed between 300-500mm/min. It is crucial to avoid weld burn-through or coarse grain problems caused by excessive current, and to optimize the weld pool formation through the robot's arc-swinging function.
For stainless steel structure welding, the focus should be on preventing oxidation and intergranular corrosion. Robotic processes are preferred, using TIG welding or pulsed MIG welding. ER308 and ER316 series welding wires are used for different stainless steel grades. The shielding gas should be pure Ar or 98% Ar + 2% O₂. Parameter settings should minimize heat input, with current controlled at 120-200A and voltage at 18-24V. Precise robot path control is crucial to reduce weld dwell time and prevent chromium burn-off.
For low-alloy high-strength steel welding, controlling cold cracking is key. Robotic processes require preheating (80-150℃) using low-hydrogen flux-cored wire and an argon-rich shielding gas mixture. Welding parameters should balance penetration and toughness, with current at 160-220A and voltage at 20-26V. The robot's multi-layer, multi-pass welding capabilities should be utilized, with post-weld temperature control after each layer to prevent stress concentration.
In short, the matching process needs to be based on the material characteristics, combined with the robot's parameter programmability and path accuracy, and the welding method, filler material and heat input should be adjusted accordingly in order to achieve high-quality welding without trial teaching.