ER2209 Duplex Stainless TIG Rod 1/8" (10lb Tube)

Technical Overview: ER2209 Duplex Stainless Steel Filler Metal

The ER2209 TIG Welding Rod is a premium filler metal engineered for the Gas Tungsten Arc Welding (GTAW) of duplex stainless steels, specifically UNS S31803 and S32205 (commonly known as 2205). This alloy is characterized by a microstructure consisting of approximately equal parts austenite and ferrite, which imparts mechanical properties superior to standard 300-series stainless steels. With a composition enriched in 22% Chromium, 8.5-9.5% Nickel, and 3% Molybdenum, ER2209 delivers exceptional resistance to pitting and chloride-ion stress corrosion cracking (SCC).

Metallurgical Performance

Welding duplex stainless steel requires careful heat input management to maintain the correct phase balance. ER2209 is over-alloyed with nickel compared to the base metal to promote the formation of austenite in the weld bead during cooling, ensuring the weld metal matches the toughness and corrosion resistance of the base plate. It typically exhibits a Pitting Resistance Equivalent Number (PREN) greater than 35, making it suitable for aggressive environments such as seawater, sour gas, and chemical processing.

Application Guidelines

• Shielding Gas: 100% Argon is standard; however, Argon-Helium mixtures can be used to improve penetration. Nitrogen additions to the shielding gas can also help maintain the austenite balance and pitting resistance.
• Preparation: Ensure base metals are cleaned of all oxides and hydrocarbons. Use stainless steel wire brushes dedicated to the material to prevent cross-contamination.
• Technique: Maintain a short arc length and use stringer beads. Avoid excessive heat input to prevent the formation of detrimental intermetallic phases.

This 1/8" (3.2mm) diameter rod is ideal for root passes in thicker pipe or fill passes in plate welding. The 10 lb packaging ensures sufficient material for substantial project runs while protecting the rod surface from oxidation and moisture absorption.