UNS S17600 (Alloy 635) Stainless Steel
S17600 stainless steel is a precipitation-hardening stainless steel formulated for primary forming into wrought products. S17600 is the UNS number for this material. Alloy 635 is the common industry name.
The properties of S17600 stainless steel include four 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 S17600 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
270 to 410
Elastic (Young's, Tensile) Modulus
200 GPa 28 x 106 psi
Elongation at Break
8.6 to 11 %
Fatigue Strength
300 to 680 MPa 43 to 99 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
28 to 50 %
Rockwell C Hardness
28 to 44
Shear Modulus
76 GPa 11 x 106 psi
Shear Strength
560 to 880 MPa 81 to 130 x 103 psi
Tensile Strength: Ultimate (UTS)
940 to 1490 MPa 140 to 220 x 103 psi
Tensile Strength: Yield (Proof)
580 to 1310 MPa 84 to 190 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
550 °C 1030 °F
Maximum Temperature: Mechanical
890 °C 1630 °F
Melting Completion (Liquidus)
1430 °C 2610 °F
Melting Onset (Solidus)
1390 °C 2530 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.9 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.7 % IACS
Otherwise Unclassified Properties
Base Metal Price
13 % relative
Density
7.8 g/cm3 480 lb/ft3
Embodied Carbon
2.9 kg CO2/kg material
Embodied Energy
42 MJ/kg 18 x 103 BTU/lb
Embodied Water
130 L/kg 16 gal/lb
Common Calculations
PREN (Pitting Resistance)
17
Resilience: Ultimate (Unit Rupture Work)
70 to 150 MJ/m3
Resilience: Unit (Modulus of Resilience)
850 to 4390 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
34 to 54 points
Strength to Weight: Bending
28 to 37 points
Thermal Diffusivity
4.1 mm2/s
Thermal Shock Resistance
31 to 50 points
Alloy Composition
Among wrought stainless steels, the composition of S17600 stainless steel is notable for including aluminum (Al) and titanium (Ti). Aluminum is used to improve oxidation resistance. It can also enhance the effects of heat treatment. Titanium is used to broadly improve mechanical properties.
| Fe | 71.3 to 77.6 | |
| Cr | 16 to 17.5 | |
| Ni | 6.0 to 7.5 | |
| Ti | 0.4 to 1.2 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| Al | 0 to 0.4 | |
| C | 0 to 0.080 | |
| 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 A693: Standard Specification for Precipitation-Hardening Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
ASTM A564: Standard Specification for Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels
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