What is the method for welding galvanized steel sheets on car bodies?
4 Answers
The method for welding galvanized steel sheets on car bodies is: using electrode manual arc welding to hold the electrode, increasing the arc height to enhance arc blowing force, applying high current to burn through the galvanized sheet workpiece, and continuously moving the electrode forward to form a continuous cutting seam. Galvanized steel sheets are coated with a layer of zinc metal on the surface to prevent corrosion and extend their service life. These zinc-coated steel sheets are called galvanized sheets. Passenger cars have widely adopted galvanized steel sheets, with thicknesses ranging from 0.5 to 3.0mm, where body panels mostly use galvanized steel sheets with a thickness of 0.6 to 0.8mm.
In my years of experience as a car enthusiast, I've tried welding galvanized steel sheets several times. While galvanized sheets have strong rust resistance, you really need to be careful during welding to avoid bubbling when the zinc layer melts, which can lead to rust or porosity defects. I usually use resistance spot welding—it's straightforward: just polish the welding points to remove the surface zinc layer and quickly press with a spot welder. That's how I fixed the chassis of my vintage car. Remember to adjust the current intensity properly—too high and it's easy to burn through. Laser welding is trendy now, but the equipment is too expensive for DIY. No matter the method, I always check if the seams are solid after welding, and ventilation is crucial—zinc fumes aren't good to inhale. Spot welding is efficient and practical for body repairs, making it suitable for average hobbyists.
At the body manufacturing plant, I primarily use spot welding and laser welding when working with galvanized sheets. Spot welding is fast and cost-effective, joining metals instantly through resistance heat; however, zinc layer evaporation may cause pores, requiring adjustments to current duration or grinding the welding area surface. Laser welding is more precise, with minimal heat impact that preserves the zinc layer, but it involves higher equipment costs and is used in premium vehicle production. Regardless of the method, ensuring a clean, impurity-free work area is crucial. Post-welding, I always test the strength to prevent weak joints. This work directly impacts the vehicle's structural safety—no room for carelessness. Routine maintenance should focus on monitoring connection point conditions.
When teaching auto repair, I always emphasize the fundamentals of welding galvanized car body panels. Start with spot welding because it's easy to learn and fast to operate; the key is to grind the welding points to remove zinc debris, then use a spot welder to clamp the metal sheets. The zinc coating tends to vaporize when heated, leading to defects, so beginners must practice controlling the current intensity. Laser welding is more advanced but requires higher technical skills. After welding, always check the joint strength to prevent future rusting. Safety first—wear gloves and goggles. Actually, galvanized panels are meant to prevent rust, but improper welding can shorten the car body's lifespan.
