1. Description
ER309 is a 23% Cr / 13% Ni austenitic stainless steel welding wire designed for GMAW (MIG) and GTAW (TIG) processes. Due to its high chromium and nickel content, ER309 provides exceptional heat resistance and superior corrosion resistance. It is primarily engineered for joining dissimilar metals, such as stainless steel to carbon/low-alloy steel, and for applying stainless steel cladding/overlays on mild steels.
2. Applications
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Dissimilar Metals: Welding 300-series stainless steels (e.g., 304, 304L, 308) to carbon steels or low-alloy steels.
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Buffer Layers / Overlays: Applying initial corrosion-resistant clad layers on mild steel prior to welding with ER308L or ER316L.
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High-Temperature Service: Joining 309-type base metals used in furnace components, heat exchangers, exhaust systems, and kiln liners operating up to 1000°C (1832°F).
3. Chemical Composition of Solid Wire (Wt %)
Conforms to AWS A5.9 / EN ISO 14343-A standards
| Element | C | Si | Mn | P | S | Cr | Ni | Mo | Cu |
| Min. (%) | — | 0.30 | 1.00 | — | — | 23.0 | 12.0 | — | — |
| Max. (%) | 0.12 | 0.65 | 2.50 | 0.030 | 0.030 | 25.0 | 14.0 | 0.75 | 0.75 |
