Chemical components

Product Description

ER309L is a low-carbon austenitic stainless steel filler metal compliant with AWS A5.9/A5.9M standards, designed for welding dissimilar metals such as joining 300-series stainless steels to carbon steel or low-alloy steels. With a maximum carbon content of 0.03%, it provides superior resistance to intergranular corrosion without requiring stabilizers like niobium or titanium. Featuring an alloy composition of 23.0-25.0wt.% chromium and 12.0-14.0wt.% nickel, it forms an austenitic-ferritic duplex structure with 5-15% ferrite content (FN). Compatible with GMAW (MIG), GTAW (TIG), and SAW processes using appropriate shielding gases, it supports welding of similar alloys, overlay applications, and dissimilar joints where high corrosion resistance is required.

Features

▪ Superior Intergranular Corrosion Resistance: The ultra-low carbon content (≤0.03%) significantly reduces carbide precipitation during welding, providing excellent resistance to intergranular corrosion without the need for stabilizing elements. This makes ER309L ideal for harsh corrosive environments and applications requiring post-weld corrosion performance.
▪ Excellent Dissimilar Welding Capability: High chromium-nickel content (23-25% Cr, 12-14% Ni) provides excellent dilution tolerance for welding stainless steels to carbon or low-alloy steels. The balanced ferrite content (5-15 FN) ensures good hot cracking resistance and metallurgical compatibility in complex dissimilar joints and overlay applications.
▪ Balanced Mechanical Properties: Typical tensile strength of 550-600 MPa (80,000-87,000 psi), yield strength of 380-410 MPa (55,000-59,500 psi), and elongation of 36-47%. While slightly lower in strength than standard ER309 due to reduced carbon content, it maintains excellent toughness and ductility across a wide temperature range. Suitable for service temperatures up to 700°F (371°C) under normal conditions.

Applications

▪ Ideal for corrosion-critical dissimilar metal welding and overlay applications, ER309L is widely used in:
▪ Chemical & Petrochemical: Pressure vessels, storage tanks, reactors, and piping systems handling corrosive media where intergranular corrosion resistance is critical. Used for cladding carbon steel vessels with stainless steel overlay.
▪ Dissimilar Metal Joining: Welding 300-series stainless steels (304, 316) to carbon steel, low-alloy steel, or ferritic stainless steels in power generation, oil and gas, and general fabrication. Preferred for joints that will undergo heat treatment.
▪ High-Purity Applications: Food processing equipment, beverage tanks, and pharmaceutical industry components where corrosion resistance and clean weld appearance are essential. The low carbon content prevents sensitization in critical applications.
▪ Overlay & Buttering: Stainless steel overlay on carbon or low-alloy steel substrates for corrosion resistance enhancement. Used as a buffer layer in multi-layer cladding applications and for buttering passes before welding dissimilar metals.