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AISI 347 (S34700) Stainless Steel

AISI 347 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. 347 is the AISI designation for this material. S34700 is the UNS number. Additionally, the British Standard (BS) designation is 347S17.

The properties of AISI 347 stainless steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AISI 347 stainless steel to: wrought austenitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Brinell Hardness

160 to 210

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 106 psi

Elongation at Break

34 to 46 %

Fatigue Strength

220 to 270 MPa 32 to 40 x 103 psi

Poisson's Ratio

0.28

Shear Modulus

77 GPa 11 x 106 psi

Shear Strength

430 to 460 MPa 62 to 67 x 103 psi

Tensile Strength: Ultimate (UTS)

610 to 690 MPa 89 to 100 x 103 psi

Tensile Strength: Yield (Proof)

240 to 350 MPa 35 to 50 x 103 psi

Thermal Properties

Latent Heat of Fusion

290 J/g

Maximum Temperature: Corrosion

480 °C 900 °F

Maximum Temperature: Mechanical

870 °C 1600 °F

Melting Completion (Liquidus)

1430 °C 2600 °F

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

16 W/m-K 9.3 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.4 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.7 % IACS

Otherwise Unclassified Properties

Base Metal Price

19 % relative

Calomel Potential

-80 mV

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

3.6 kg CO2/kg material

Embodied Energy

52 MJ/kg 22 x 103 BTU/lb

Embodied Water

150 L/kg 17 gal/lb

Common Calculations

PREN (Pitting Resistance)

18

Resilience: Ultimate (Unit Rupture Work)

190 to 220 MJ/m3

Resilience: Unit (Modulus of Resilience)

150 to 310 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

22 to 25 points

Strength to Weight: Bending

20 to 22 points

Thermal Diffusivity

4.3 mm2/s

Thermal Shock Resistance

13 to 15 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 347 stainless steel is notable for including niobium (Nb). Niobium is primarily used to improve yield strength, particularly at elevated temperatures.

Iron (Fe)Fe 64.1 to 74
Chromium (Cr)Cr 17 to 19
Nickel (Ni)Ni 9.0 to 13
Manganese (Mn)Mn 0 to 2.0
Niobium (Nb)Nb 0 to 1.0
Silicon (Si)Si 0 to 0.75
Carbon (C)C 0 to 0.080
Phosphorus (P)P 0 to 0.045
Sulfur (S)S 0 to 0.030

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005

ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels

Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002

Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011

Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994

Advances in Stainless Steels, Baldev Raj et al. (editors), 2010