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309 Stainless Steel Sheet & Plate

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309 Stainless Steel Sheet & Plate (UNS S30908,1.4828)

At DNYA Stainless Steel, we offer high-performance 309 Stainless Steel Sheets & Plates, a heat-resistant austenitic alloy engineered for elevated temperature applications and excellent oxidation resistance. With its high chromium and moderate nickel content, 309 (UNS S30908 / 1.4828) is designed to withstand thermal cycling, oxidation, and corrosion at temperatures up to 1000°C (1832°F).

 

If your project demands reliable stainless steel for heat treatment equipment, furnaces, exhaust systems, or thermal process components, 309 stainless steel delivers performance, durability, and value.

 

What is 309 Stainless Steel?

309 stainless steel is an austenitic chromium-nickel alloy designed for superior high-temperature oxidation resistance and structural stability. It contains higher chromium (22–24%) and nickel (12–15%) content than standard 304 or 316 stainless steels, providing excellent strength and corrosion resistance in service temperatures well beyond 850°C.

Due to its balance of strength, corrosion resistance, and thermal endurance, 309 is a preferred material for components exposed to high heat, combustion gases, and thermal cycling.

 

Key Features 

  • Excellent High-Temperature Resistance
    Oxidation-resistant in continuous service up to 1000°C and intermittent exposure up to 1100°C.

  • Superior Oxidation & Scaling Resistance
    Resists spalling and corrosion in oxidizing environments.

  • Good Mechanical Strength at Elevated Temperatures
    Retains toughness and formability when hot.

  • Non-Magnetic in Annealed Condition
    Becomes slightly magnetic with cold work.

  • Strong Fabricability & Weldability
    Easy to machine, form, and weld using conventional methods.

  • Versatile Across Industries
    Used in furnace parts, exhausts, thermal shields, and petrochemical processing.

Available Thickness

3/16″1/4″5/16″3/8″1/2″5/8″3/4″1″
4.8mm6.3mm7.9mm9.5mm12.7mm15.9mm19mm25.4mm
1 1/4″1 1/2″1 5/8″1 3/4″2″2 1/2″3″
31.8mm38.1mm41.3mm44.5mm50.8mm63.5mm76.2mm
309-stainless-steel-sheet-plate

Application

  • Automotive
  • Chemical and Pharmaceutical
  • Fertilizer
  • Food Processing and Handling
  • Manufacturing
  • Mining
  • Oil & Gas
  • Phosphate Mining

Standard

  • ASTM A240 / A240M
  • ASTM A276 / A276M
  • ASTM A312 / A312M
  • ISO 15510
  • EN 10088-2
  • IN 10204
  • HE G4304
  • HE G4305
  • ASME SA240 / SA240M
  • ASME SA312 / SA312M

Corrosion Resistance

  • Oxidation Resistance: Stainless Steel 309 performs well in oxidative environments, thanks to its high chromium content. It can withstand high temperatures and resist scaling, making it suitable for applications where exposure to air or gases at elevated temperatures is common.
  • Sulfur Dioxide: This grade has good resistance to sulfur dioxide and other sulfur-containing gases, which can be corrosive to many other materials.
  • Corrosive Environments: While it offers better resistance to high temperatures than some other grades, Stainless Steel 309 is not as resistant to corrosion in chloride environments compared to grades like 316. For applications with high chloride exposure, a different grade might be more appropriate.
  • Thermal Cycling: It maintains its resistance to corrosion even with thermal cycling, which is when the material undergoes repeated heating and cooling.

309 Chemical Composition

Element% by Weight (Typical)
Chromium (Cr)24.0 – 26.0
Nickel (Ni)13.0 – 15.0
Carbon (C)≤ 0.15
Manganese (Mn)≤ 2.0
Silicon (Si)≤ 1.0
Phosphorus (P)≤ 0.045

309 Physical Properties

PropertyValue
Density~7.9 g/cm³
Melting Point~1400-1450°C
Thermal Conductivity~15.5 W/m·K
Specific Heat Capacity~500 J/kg·K
Modulus of Elasticity~200 GPa
Poisson’s Ratio~0.30

309 Mechanical Properties

Property Value
Yield Strength (0.2% offset) ~205 MPa
Tensile Strength ~510 MPa
Elongation (in 50 mm) ~40%
Hardness (Rockwell B) ~80 HB
Modulus of Elasticity ~200 GPa
Poisson’s Ratio ~0.30

Fabrication Data

  1. Machining
  • Machinability: Stainless Steel 309 is harder than many other stainless steels, which can make machining more challenging. Using sharp tools and appropriate cutting speeds is crucial.
  • Cutting Tools: Carbide-tipped tools are often recommended for better performance and longevity.
  1. Welding
  • Welding Methods: Common methods include TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding. Pre-heating is not typically required, but post-weld heat treatment may improve properties.
  • Filler Material: Use a filler material compatible with 309, such as 309L, to ensure similar corrosion and mechanical properties.
  • Heat Treatment: After welding, a post-weld annealing process can help reduce residual stresses and improve corrosion resistance.
  1. Heat Treatment
  • Solution Annealing: Heat to approximately 1050-1150°C (1920-2100°F) and rapidly cool. This process helps to dissolve any carbides and ensures a uniform microstructure.
  • Stress Relieving: If the material has been subjected to stress, stress-relieving heat treatment at around 700-800°C (1290-1470°F) can be beneficial.
  1. Forming
  • Cold Working: Stainless Steel 309 can be cold worked but may require more force compared to other grades due to its hardness.
  • Hot Working: Hot working should be done at temperatures above 1000°C (1830°F) to avoid work hardening and to maintain ductility.
  1. Surface Treatment
  • Pickling and Passivation: These processes can help remove surface contaminants and enhance corrosion resistance. Pickling involves acidic cleaning, while passivation forms a protective oxide layer.
  1. Cleaning
  • Cleaning: Use non-abrasive cleaners and avoid chloride-based cleaners to prevent surface damage and potential corrosion.
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For more information or to request a quote, contact us today to discuss how Stainless Steel Plate 309 can meet your specific project needs.