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Stainless Steel - Grade 309VSi / 1.4828

Description

Stainless Steel Grade 309VSi/1.4828 is a high-temperature chromium-nickel austenitic stainless steel known for its excellent oxidation resistance at elevated temperatures. It can withstand temperatures up to 1900°F (1038°C) in dry air and exhibits good resistance to sulfidation. However, it has limited resistance to carburization and is not suitable for highly carburizing environments. The alloy is non-magnetic in both annealed and cold-worked states and offers corrosion resistance comparable to Type 304/304L stainless steels.

Chemical Composition

The chemical composition of 309VSi typically includes:

Element Composition (%)
Carbon (C) 0.20 max
Silicon (Si) 1.00 max
Manganese (Mn) 2.00 max
Phosphorus (P) 0.045 max
Sulfur (S) 0.030 max
Chromium (Cr) 22.0 - 24.0
Nickel (Ni) 12.0 - 15.0
Iron (Fe) Balance

Mechanical Properties

At room temperature, the mechanical properties of 309VSi are as follows:

Property Value
Tensile Strength (MPa) 560 (minimum)
Proof Stress (0.2% Offset) (MPa) 285 (minimum)
Elongation (% in 50mm) 40%
Hardness (Brinell) 40

At elevated temperatures, the tensile stress values are:

Temperature (°C) Tensile Stress (MPa)
550 440
650 360
750 240
850 150
950 70
1050 30

Thermal & Physical Properties

  • Maximum Recommended Service Temperature:
  • Continuous: 1100°C
  • Intermittent: 980°C
  • Thermal Conductivity: Low thermal conductivity, which contributes to hot cracking during welding.
  • Coefficient of Thermal Expansion: Relatively high, impacting the design of components subjected to temperature variations.

    • Other Designations

  • UNS: S30900
  • ASTM: A240
  • ASTM: A167
  • DIN: 1.4828

    • Fabrication and Heat Treatment

  • welding: 309VSi/1.4828 can be welded using all common processes. For best results, filler metals such as ER309Si or ER308 can be used to enhance weld pool fluidity.
  • Hot Working: Recommended forging temperatures range from 980°C to 1120°C, with finishing temperatures no cooler than 980°C.
  • Annealing: Heat treatment should be performed between 1050°C and 1150°C followed by water quenching to ensure all carbides are in solution.
  • Stress Relieving: Conducted at temperatures between 250°C and 400°C for about one hour.

    • Applications

    309VSi is primarily used in applications requiring high-temperature oxidation resistance, such as:

  • Furnace components
  • Heat exchangers
  • Industrial ovens
  • Exhaust systems in power generation
  • Applications in petrochemical industries

    • Supplied Forms

    309VSi is available in various forms, including:

  • Sheets
  • Plates
  • Bars
  • Rods
  • Tubes

    • Features

  • Excellent oxidation resistance at high temperatures
  • Good mechanical properties at elevated temperatures
  • Fabricable and weldable using standard practices
  • Non-magnetic in both annealed and cold-worked conditions.

    • This datasheet provides a comprehensive overview of the 309VSi/1.4828 stainless steel grade, highlighting its properties, applications, and fabrication methods.

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