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.
| Fe | 64.1 to 74 | |
| Cr | 17 to 19 | |
| Ni | 9.0 to 13 | |
| Mn | 0 to 2.0 | |
| Nb | 0 to 1.0 | |
| Si | 0 to 0.75 | |
| C | 0 to 0.080 | |
| P | 0 to 0.045 | |
| 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