T439-16 - ER439 Stainless TIG Rod 1/16" - Automotive Exhaust Welding Wire

Technical Overview of Exocor ER439 TIG Welding Rod

The Exocor ER439 TIG Welding Rod is a premium ferritic stainless steel filler metal designed specifically for the Gas Tungsten Arc Welding (GTAW) process. Classified under AWS A5.9 as ER439, this alloy is formulated with approximately 18% chromium and is stabilized with titanium. The addition of titanium is critical as it acts as a carbide former, preventing the precipitation of chromium carbides at the grain boundaries. This stabilization mechanism significantly enhances the material's resistance to intergranular corrosion and sensitization, particularly in the heat-affected zone (HAZ) after welding.

This consumable is the preferred choice for welding AISI Type 409 and 439 ferritic stainless steels, materials commonly utilized in the automotive industry for exhaust system components. Unlike austenitic stainless fillers (such as ER308L or ER309L), ER439 shares a similar coefficient of thermal expansion with ferritic base metals. This compatibility reduces thermally induced stresses during heating and cooling cycles, thereby minimizing the risk of fatigue cracking in high-temperature service environments like exhaust manifolds and catalytic converters.

The 1/16" (1.6mm) diameter provides excellent control for thin-wall tubing and sheet metal applications often found in automotive fabrication. The rod produces a weld deposit with good oxidation resistance up to elevated temperatures, ensuring the longevity of the repair or fabrication. It is recommended to use 100% Argon shielding gas to maintain the integrity of the titanium stabilization and ensure a clean, defect-free weld puddle. This product is supplied in a 4.5kg (approx. 10lb) protective tube to prevent contamination and moisture pickup during storage.

Material Specifications and Performance

ER439 is engineered to match the mechanical and chemical properties of modern ferritic stainless steels. The higher chromium content compared to ER409 provides improved corrosion resistance, making it suitable for more demanding environments where road salts and condensate are factors. While primarily used for automotive applications, it is also applicable in any fabrication scenario requiring the joining of 18% chromium ferritic stainless steels where post-weld heat treatment is not feasible.