How to achieve brazing between aluminum alloy and stainless steel

Issuing time:2026-05-25 15:10

Brazing of aluminum alloy tubes and stainless steel tubes is a type of dissimilar metal joining with high technical difficulty. Aluminum (Al) and iron (Fe) have a large difference in melting points, and brittle intermetallic compounds such as FeAl₃ are easily formed. Direct brazing is likely to cause brittle fracture of the joints. Selecting high-quality dedicated brazing materials and optimized brazing processes is the key to achieving reliable brazed connections between aluminum alloy tubes and stainless steel tubes.

With years of R&D accumulation, Xinrui has developed a special brazing material for aluminum and stainless steel: stainless steel flux-cored brazing rings. The product is now in mass production for well-known air conditioner manufacturers at home and abroad. We welcome new and existing customers to conduct technical exchanges and tests.

Technical points:

（1Suitable brazing processes: brazing in a nitrogen-protected furnace, high-frequency induction brazing, and flame brazing.

（2Connector design: Aluminum tube flared end, stainless steel insert into aluminum tube. Aluminum alloy tube grade:3003，6063Stainless steel pipe grade:304，316L。

（3Welding steps:

Pre-brazing cleaning ensures no oil contamination.→ Nitrogen gas is used for protection inside the tube during flame or high-frequency brazing. → Process control: Strictly control temperature and time to prevent the compound layer from becoming too thick. → After brazing, allow the material to cool naturally or air cool; rapid water cooling is prohibited. → The flux residue after brazing is non-corrosive and does not require water washing or acid washing.

（4）No heat shrink tubing is needed after brazing aluminum and stainless steel. Because the connection potential difference between aluminum and stainless steel is low, it can be designed as..."aluminum+Stainless steel+CopperThe connection method reduces the potential difference between the copper and aluminum tubes.