EX3470000000930TL0 - Exocor Executive ER347 Stainless TIG Rod 3/32" x 36"

Technical Overview of Exocor Executive ER347

The Exocor Executive ER347 is a premium-grade austenitic stainless steel TIG welding rod designed specifically for joining base metals of similar composition, such as AISI 347 and 321. The defining characteristic of this alloy is the addition of Niobium (also known as Columbium) and Tantalum. These elements act as strong carbide formers, having a greater affinity for carbon than chromium does. By preferentially forming niobium carbides, the alloy prevents the depletion of chromium at the grain boundaries—a phenomenon known as sensitization—which is the primary cause of intergranular corrosion in standard stainless steels when exposed to service temperatures between 800°F and 1500°F (427°C - 816°C).

This filler metal is manufactured under Exocor's "Executive" line, ensuring strict adherence to AWS A5.9 specifications. The chemical composition is tightly controlled to ensure the Niobium content is at least ten times the carbon content, maximizing stabilization. This makes ER347 the mandatory choice for applications involving polythionic acid stress corrosion cracking or where post-weld heat treatment (annealing) is not feasible. It is also suitable for welding standard 304 and 304L grades when a stabilizer is required for high-temperature service, although it is primarily engineered for the stabilized grades.

Metallurgically, the weld deposit exhibits a microstructure that balances austenite with a controlled ferrite number (typically 5-10 FN). This ferrite content is crucial for preventing hot cracking (solidification cracking) during the welding process, a common issue in fully austenitic weld metals. However, engineers should note that while the ferrite prevents cracking, excessive dilution with base metals containing very low ferrite could alter this balance. The rod's surface finish is chemically cleaned and matte-finished to ensure smooth feeding and optimal electrical conductivity during the GTAW process.