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In our daily lives, stainless steel has become an indispensable part of our lives. Whether it’s the wok in the kitchen, tableware, bridges, tunnels in buildings, or even medical equipment, we can’t do without this magical metal material. Today, we will introduce a special type of stainless steel – 309S stainless steel. What exactly is it made of? What are its unique properties? What fields does it apply to? Let’s uncover the mystery of 309S stainless steel together!
What is 309S stainless steel?
Stainless steel is an alloy of iron and chromium used in various applications in many industries. It is particularly valued for its corrosion resistance and strength at high temperatures. A stainless steel particularly suitable for certain applications is 309S stainless steel, also known as UNS S30908.
309S is an austenitic chromium-nickel stainless steel commonly used in high-temperature applications. The high chromium and nickel content of 309S makes it highly corrosion-resistant, while the low carbon content helps prevent carbide precipitation during welding. This makes 309S an ideal choice for many furnace and boiler applications.
What are the properties of 309S stainless steel?
- Moderate high-temperature strength
- Easy to manufacture
- Good resistance to vulcanization
- Good welding performance
What is the composition of 309S stainless steel?
It is an austenitic chromium-nickel stainless steel with a chromium content of about 19% and a nickel content of about 9%. The higher chromium and nickel content makes it more resistant to corrosion than 304 stainless steel. It is commonly used in high-temperature applications such as furnaces, kilns, and ovens.
- Carbon C:≤0.08
- Manganese Mn:≤2.00
- Silicon Si:≤1.00
- Chromium Cr: 22.0-24.0
- Nickel Ni: 12.0-15.0
- Phosphorus P:≤0.045
- Sulfur S:≤0.030
- Nitrogen N: 0.10~0.16
What are the mechanical properties of 309S stainless steel?
It is an austenitic chromium-nickel stainless steel with good formability and welding properties. Due to its relatively high carbon content, 309S is more resistant to intergranular corrosion than 304 and 310 grades of stainless steel.
The mechanical properties of 309S stainless steel are as follows:
- Yield strength: ≥ 205 MPa
- Tensile strength: ≥ 520 MPa
- Elongation after fracture: ≥ 40%
- Hardness (Hv): ≤ 200
- Density: 7.89 g/cm³
- Melting point: 1480-1530 °C
- Annealing temperature: 1000-1150 °C
What are the thermal properties of 309S stainless steel?
It is an austenitic chromium-nickel stainless steel with excellent corrosion resistance and heat resistance. The thermal properties of 309S stainless steel include high melting point, high thermal conductivity, and low thermal expansion coefficient. These properties make 309S an ideal material for high-temperature applications, such as furnaces and industrial heat exchangers.
How about the oxidation resistance of 309S?
The carbon content of 309S is the highest at 0.08%, while the carbon contents of 304 and 310 grades are 0.04% and 0.05% respectively. Therefore, 309S is commonly used in welding applications that require frequent interruptions, such as the food, beverage, and pharmaceutical industries. In addition, 309S has good oxidation resistance and can withstand temperatures up to 1900°F before scaling occurs.
What are the applications of 309S stainless steel?
It is widely used in high-temperature applications. Its high chromium and nickel content provides considerable corrosion resistance, excellent oxidation resistance, and excellent heat resistance. When operated in the range of 900-1600°F (425-870°C), 309S exhibits good creep strength and is suitable for various applications, including:
- Furnace lining
- Kiln lining
- Annealing cover
- Radiation tube
- Heat exchanger
Why Choose Sino Stainless Steel?
Thank you for reading our article and we hope it can help you to have a better understanding of the compositions, properties, and applications of 309S stainless steel. If you want to learn more about stainless steel, we’d advise you to visit Sino Stainless Steel for more information.
As a leading supplier of stainless steel products across the world, Sino Stainless Steel provides customers with high-quality stainless steel coils, stainless steel strips, stainless steel sheets, stainless steel bars, stainless steel tubes, and stainless steel wires at a very competitive price.