S527508-I26 - Hobart ER309LSi .035 Stainless MIG Wire 30lb Spool

Technical Overview of Hobart ER309LSi Stainless Steel Wire

The Hobart 309L Hi Sil is a premium quality austenitic stainless steel solid wire designed for Gas Metal Arc Welding (GMAW). This electrode conforms to AWS A5.9 classifications for ER309LSi. The primary metallurgical distinction of this alloy is its elevated silicon content (typically 0.65% to 1.00%), which significantly alters the fluid dynamics of the molten weld pool. In standard 300-series stainless steel welding, the puddle can often be sluggish, leading to high-crowned beads and potential lack of fusion at the toes. The addition of silicon in the Hobart 309LSi formulation lowers the surface tension of the molten metal, promoting superior wetting action. This results in a flatter bead profile, smoother tie-ins, and improved wash at the edges of the weld.

Metallurgically, the 'L' designation indicates a low carbon content (maximum 0.03%), which is critical for preventing sensitization. By minimizing carbon availability, the formation of chromium carbides at the grain boundaries is inhibited during the cooling cycle, thereby maintaining the corrosion resistance of the heat-affected zone (HAZ) against intergranular attack. This makes the wire suitable for applications where the weldment will be exposed to corrosive environments or high temperatures.

The 309LSi alloy is specifically engineered for joining dissimilar metals, such as welding Type 304 or 316 stainless steels to mild or low-alloy carbon steels. It is also the preferred choice for depositing buffer layers on carbon steel prior to cladding with 308 or 316 grades. The high alloy content (roughly 24% Chromium and 13% Nickel) accounts for dilution from the mild steel base metal while still retaining an austenitic microstructure in the weld deposit. This 30lb spool is wound for industrial use, ensuring consistent feedability and arc stability in automated or semi-automated setups.