Stainless Steel 347H Properties

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Stainless Steel 347H Properties

Stainless Steel 347H is an austenitic stainless steel that stands out due to its remarkable resistance to intergranular corrosion and its ability to withstand high temperatures. This grade, known for its high carbon content, enhances its creep resistance, making it an ideal choice for applications requiring prolonged exposure to elevated temperatures.

One of the key benefits of Stainless Steel 347H is its excellent oxidation resistance, which remains effective even at temperatures up to 1500°F (816°C). This property makes it particularly suitable for high-pressure boiler tubes, radiant superheaters, and high-temperature chemical processes. Additionally, it is commonly used in the aerospace industry, furnace parts, and in the manufacturing of equipment that processes high-temperature gases.

Another significant advantage of 347H is its resistance to sensitization, thanks to its stabilization with niobium. This stabilization helps in preventing chromium carbide precipitation at grain boundaries, thus ensuring that the steel retains its corrosion resistance in as-welded conditions. This characteristic is especially beneficial in environments where welding is frequent, as it reduces the risk of weld decay.

At Ferrobend, we understand the importance of quality and reliability in your projects. Our Stainless Steel 347H products are manufactured to the highest standards, ensuring superior performance and longevity. Whether you are working on industrial furnaces, heat exchangers, or any high-temperature application, Ferrobend's 347H offers unmatched reliability and efficiency.

Chemical Properties:

Elements Cr Ni C Si Mn P S Mo Fe
% min: 17.0 ,max:19.0 min: 8.0 ,max: 10.0 0.15 max 1.00 max 2.0 max 0.20 max 0.15 min 0.75 balance

Mechanical Properties:

Tensile Strength ksi (min.) Yield Strength 0.2% Offset ksi (min.) Elongation - % in 50 mm (min.) Hardness (Brinell) MAX Hardness (Rockwell B) MAX
75 30 35 228 -

Physical Properties:

Denstiy lbm/in3 Coefficient of Thermal Expansion (min/in)-°F Electrical Resistivity mW-in Thermal Conductivity BTU/hr-ft-°F Melting Range
at 68 °F at 68 – 212°F at 68 – 932°F at 68 – 1450°F at 68°F at 212°F at 392°F at 752°F at 1112°F at 1472°F at 68 – 212°F -
0.29 9.2 10.4 10.9 28.3 30.7 33.8 39.4 43.7 47.6 113.2 2552°F

Equivalent Grades and Designations:

SAE / AISI 303
UNS S30300
EN Material Number 1.4305
EN Material Name X8CrNiS18-9
DIN Material Name X8CrNiS18-9
JIS SUS 303
BS 202S 21 En58M

Heat Resistance:

  • Good oxidation resistance at temperatures up to 1700oF (927 oC)
  • Continuous use at temperatures above 1400oF (760oC) is not usually recommended due to carbide precipitation which can lead to irregular scaling
  • Does not have a low carbon content so it is also vulnerable to sensitization

Welding Characteristics:

  • Not generally recommended, but may be welded with some difficulty
  • May be welded with Alloy 310 electrodes
  • Should be annealed after welding to re-dissolve precipitated carbides

Machinability:

  • High machining rates can be obtained in the annealed condition with hardness in the range of 200 to 240 Brinell
  • Will work harden; therefore, it should be machined at reduced surface feet per minute and heavier feeds to prevent glazing at the tool interface.

Applications:

  • Nuts and bolts
  • Aircraft fittings
  • Gears
  • Screws
  • Shafts
  • Electrical switchgear components
  • Bushings