2025-04-21 309/309S stainless steel is an austenitic stainless steel with excellent high temperature oxidation resistance and corrosion resistance, and is widely used in high temperature environments. This steel contains a high proportion of chromium (22-24%) and nickel (12-15%), which enables it to maintain good strength and oxidation resistance at temperatures up to 1000°C. 309S is a low-carbon version of 309 stainless steel with a lower carbon content (≤0.08%), better welding performance, and effectively reduces the risk of intergranular corrosion during welding. 309/309S stainless steel is commonly used in industrial furnace components, heat treatment equipment, chemical heat exchangers and other structural materials in high temperature corrosive environments.