2026-10-13
Aluminum welding is not just about increasing current With the rapid development of electric vehicles (EVs) and lightweight automotive structures, aluminum has become increasingly important in Body-in-White (BIW) manufacturing. However, welding aluminum is fundamentally different from welding steel. Many manufacturers find that a conventional DC stud welding system can achieve stable results on steel studs but struggles when applied to aluminum components. Problems such as unstable arc behavior, porosity, insufficient fusion, and low pull strength often occur. The reason is not simply insufficient welding current. The real challenge comes from the unique physical properties of aluminum: High thermal conductivity Low melting temperature High melting point oxide layer Rapid heat dissipation These characteristics determine that aluminum stud welding requires more precise control of heat input and current direction. This is why advanced AC/DC stud welding technology has become an important solution for aluminum automotive applications. Aluminum vs Steel: Why the Welding Process Is Completely Different Although aluminum and steel can both be joined through arc welding, their melting behavior is very different. Property Steel Aluminum Impact on Welding Melting point Approx. 1500℃ Approx. 660℃ Aluminum melts much earlier Oxide layer Thin oxide film Al₂O₃ oxide layer, melting point approx. 2050℃ Oxide layer is difficult to break Thermal conductivity Approx. 50 W/(m·K) Approx. 237 W/(m·K) Heat dissipates much faster Density 7.8 g/cm³ 2.7 g/cm³ Lightweight structure advantage Molten pool stability Relatively stable Difficult to maintain Requires precise heat control The biggest challenge is the aluminum oxide layer. Although aluminum itself melts at around 660℃, the aluminum oxide layer on the surface requires temperatures above 2000℃ to break down. This means: Before the aluminum base material can melt properly, the oxide layer must first be effectively removed. Without breaking this barrier, the stud and base material cannot form a strong metallurgical bond. Why…
