ER409CB-24 - Exocor ER409Cb 3/32" Stainless Steel TIG Rod

Technical Overview of Exocor ER409Cb TIG Rod

The Exocor ER409Cb is a specialized ferritic stainless steel TIG welding rod designed primarily for the fabrication and repair of automotive exhaust systems. Classified under AWS A5.9 standards, this filler metal is chemically composed to match Type 409 stainless steel base materials, which are ubiquitous in the automotive industry for catalytic converters, mufflers, manifolds, and exhaust tubing. The 'Cb' in the designation indicates stabilization with Columbium (also known as Niobium). This addition is critical metallurgically as it preferentially forms carbides, thereby preventing chromium carbide precipitation at the grain boundaries. This stabilization mechanism significantly reduces the risk of intergranular corrosion and sensitization in the heat-affected zone (HAZ), a common failure point in unstabilized ferritic welds.

With a diameter of 3/32" (approximately 2.4mm) and a standard length of 36", this rod is optimized for manual Gas Tungsten Arc Welding (GTAW). The alloy offers excellent resistance to high-temperature oxidation and corrosion, maintaining structural integrity in the harsh thermal cycling environments typical of internal combustion exhaust systems. Unlike austenitic stainless steels (like 308L or 316L), ER409Cb is magnetic and possesses a lower coefficient of thermal expansion, making it the technically correct choice for welding 409 base metals to avoid thermal fatigue cracking.

Operators should utilize Direct Current Electrode Negative (DCEN) polarity and 100% Argon shielding gas to ensure a stable arc and clean weld deposit. The rod produces a smooth bead profile with good wetting characteristics. While post-weld heat treatment is generally not required for 409Cb due to its stabilized chemistry, proper cleaning of the base metal is essential to prevent contamination. This filler metal is strictly recommended for joining 409 to itself or to other ferritic stainless steels, ensuring the longevity and compliance of exhaust components.