Aluminum Welding Wire for Brazing Applications

Specification

Applications and Solutions

• HVAC/Refrigeration Systems: Brazing aluminum coils, manifolds, and tube assemblies in air conditioning and heat pump units.

• Automotive Heat Exchangers: Brazing radiators, intercoolers, and oil coolers, often using flux-cored wire or bare wire with Nocolok flux.

• Thin-Walled Component Joining: Applications where welding heat input would cause burn-through or excessive distortion, making brazing the preferred low-distortion solution.

• Cast-to-Wrought Connections: Joining dissimilar aluminum components where the high silicon content bridges the metallurgical differences.

FAQ

• Q: What is the main difference between aluminum welding and aluminum brazing?A: Welding melts and fuses the base metal; brazing heats the base metal below its melting point and uses a filler metal (like ER4047) with a lower melting point to flow into the joint by capillary action.

• Q: Can I use ER4043 for brazing?A: Yes, ER4043 (5% Si) can be used, but ER4047 (12% Si) is generally preferred for its lower melting point, providing superior fluidity and a safer temperature margin against melting the base metal.

• Q: Is a flux required for aluminum brazing?A: Yes, flux is almost always required to chemically remove the tenacious aluminum oxide layer, allowing the liquid filler metal to wet and flow across the joint surface effectively. Exceptions exist only for vacuum brazing.