309

309

309 is an austenitic heat resistant alloy with oxidation resistance to 1900°F under constant temperature conditions. When frequent thermal cycling is involved, the alloy is resistant to about 1850°F. The high chromium and relatively low nickel content of 309 provide good resistance to high temperature sulfur bearing atmospheres. 309 has only moderate resistance to carbon absorption and is not suggested for use in highly carburizing atmospheres.

Often in many product forms, the grain size and carbon content can meet both the 309S and 309H requirements. Prolonged exposure to the 1100-1600°F temperature range will cause some sigma to form, lowering room temperature ductility and impact resistance. Should sigma formation be anticipated, care should be taken to avoid heavy mechanical impact at room temperature. 309 has a machinability rating of 43% relative to AISI B1112 steel. Room temperature forming is suggested. Weld with AWS E309-16 covered electrodes or ER309 bare wire.

Chemistry

 CrNiCPSMnFe
MIN 22.0 12.0 - - - - -
MAX 24.0 15.0 0.08 0.045 0.03 2.0 Balance

Specifications

AMS 5523
ASME SA 240, ASME SA 312, ASME SA 479
ASTM A 240, ASTM A 276, ASTM A 276 Condition A, ASTM A 276 Condition S, ASTM A 312, ASTM A 479
EN 1.4833
UNS S30908, UNS S30909
Werkstoff 1.4833

Inventory

309 Pipe, 309 Plate, 309 Sheet, 309 Welding Products

Common Trade Names

309 Stainless

Features

  • Oxidation resistant to 1900°F
  • Moderate strength at high temperature
  • Ease of fabrication
  • Good sulfidation resistance
  • Good weldability

Applications

  • Annealing covers and boxes
  • Carbon saggers
  • Waste incinerators
  • Pulverized coal burners
  • Brazing fixtures
  • Lead pans, neutral salt pots
  • Muffles, retorts
  • Furnace fans and shafts
  • Radiant tubes for aluminum and steel annealing
  • Glass forming equipment
  • Thermowells
  • Paper mill equipment
  • Power boiler tube hangers
  • Rotary kilns and calciners
  • Anchor bolts

Physical Properties

Density: 0.285 lb/inch3
Melting Point: 2500 - 2590°F

Temperature, °F 70 1000 1200 1400 1600
Coefficient* of Thermal Expansion, in/in°F x 10-6 - 9.7 - - 10.1
Thermal Conductivity, Btu • ft/ft2 • hr • °F 7.4 11.5 12.4 - -
Modulus of Elasticity, Dynamic psi x 106 28.5 22.5 21.0 19.5 18.0

* 70°F to indicated temperature.

Mechanical Properties

Representative Tensile Properties

Temperature, °F 70 1200 1600
Ultimate Tensile Strength, ksi 90 52 18
0.2% Yield Strength, ksi 45 22 -
Elongation, % 50 26 32

Typical Creep- Rupture Properties

Temperature, °F 1200 1400 1600 1800
Minimum Creep 0.0001%/Hr, ksi 16 3.4 1.4 0.22
10,000 Hour Rupture Strength, ksi 17.2 4.8 1.6 0.56