UNS S17400 (17-4 PH, Alloy 630) Stainless Steel
S17400 stainless steel is a precipitation-hardening stainless steel formulated for primary forming into wrought products. S17400 is the UNS number for this material. 17-4 PH is the common industry name.
It has a moderately low embodied energy and can have a moderately low tensile strength among wrought precipitation-hardening stainless steels.
The properties of S17400 stainless steel include eight common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare S17400 stainless steel to: wrought precipitation-hardening 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
280 to 440
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
11 to 21 %
Fatigue Strength
380 to 670 MPa 55 to 98 x 103 psi
Impact Strength: V-Notched Charpy
7.6 to 86 J 5.6 to 63 ft-lb
Poisson's Ratio
0.28
Reduction in Area
40 to 62 %
Rockwell C Hardness
27 to 43
Shear Modulus
75 GPa 11 x 106 psi
Shear Strength
570 to 830 MPa 82 to 120 x 103 psi
Tensile Strength: Ultimate (UTS)
910 to 1390 MPa 130 to 200 x 103 psi
Tensile Strength: Yield (Proof)
580 to 1250 MPa 84 to 180 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Maximum Temperature: Corrosion
450 °C 840 °F
Maximum Temperature: Mechanical
850 °C 1570 °F
Melting Completion (Liquidus)
1440 °C 2620 °F
Melting Onset (Solidus)
1400 °C 2550 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
17 W/m-K 9.7 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.6 % IACS
Otherwise Unclassified Properties
Base Metal Price
14 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.7 kg CO2/kg material
Embodied Energy
39 MJ/kg 17 x 103 BTU/lb
Embodied Water
130 L/kg 16 gal/lb
Common Calculations
PREN (Pitting Resistance)
16
Resilience: Ultimate (Unit Rupture Work)
140 to 160 MJ/m3
Resilience: Unit (Modulus of Resilience)
880 to 4060 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
32 to 49 points
Strength to Weight: Bending
27 to 35 points
Thermal Diffusivity
4.5 mm2/s
Thermal Shock Resistance
30 to 46 points
Alloy Composition
Among wrought stainless steels, the composition of S17400 stainless steel is notable for including niobium (Nb) and copper (Cu). Niobium is primarily used to improve yield strength, particularly at elevated temperatures. Copper is used to improve resistance to acids, and to improve formability.
| Fe | 70.4 to 78.9 | |
| Cr | 15 to 17 | |
| Ni | 3.0 to 5.0 | |
| Cu | 3.0 to 5.0 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| Nb | 0.15 to 0.45 | |
| C | 0 to 0.070 | |
| P | 0 to 0.040 | |
| S | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A564: Standard Specification for Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes
Sintering of Advanced Materials: Fundamentals and Processes, Zhigang Zak Fang (editor), 2010
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
Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010