UNS S66286 (A-286, ASTM Grade 660) Stainless Steel
S66286 stainless steel is a precipitation-hardening stainless steel formulated for primary forming into wrought products. Grade 660 is the ASTM designation for this material. S66286 is the UNS number. And A-286 is the common industry name.
It has a moderately high base cost among wrought precipitation-hardening stainless steels. In addition, it can have the highest ductility and has a moderately high embodied energy.
The properties of S66286 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 S66286 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
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
17 to 40 %
Fatigue Strength
240 to 410 MPa 34 to 59 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
75 GPa 11 x 106 psi
Shear Strength
420 to 630 MPa 62 to 91 x 103 psi
Tensile Strength: Ultimate (UTS)
620 to 1020 MPa 90 to 150 x 103 psi
Tensile Strength: Yield (Proof)
280 to 670 MPa 40 to 97 x 103 psi
Thermal Properties
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
780 °C 1440 °F
Maximum Temperature: Mechanical
920 °C 1690 °F
Melting Completion (Liquidus)
1430 °C 2600 °F
Melting Onset (Solidus)
1370 °C 2500 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.7 BTU/h-ft-°F
Thermal Expansion
17 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
1.9 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.2 % IACS
Otherwise Unclassified Properties
Base Metal Price
26 % relative
Density
7.9 g/cm3 500 lb/ft3
Embodied Carbon
6.0 kg CO2/kg material
Embodied Energy
87 MJ/kg 37 x 103 BTU/lb
Embodied Water
170 L/kg 20 gal/lb
Common Calculations
PREN (Pitting Resistance)
19
Resilience: Ultimate (Unit Rupture Work)
150 to 200 MJ/m3
Resilience: Unit (Modulus of Resilience)
190 to 1150 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
22 to 36 points
Strength to Weight: Bending
20 to 28 points
Thermal Diffusivity
4.0 mm2/s
Thermal Shock Resistance
13 to 22 points
Alloy Composition
Among wrought stainless steels, the composition of S66286 stainless steel is notable for including boron (B) and vanadium (V). Boron is used to improve hardenability. It has a substantial effect when added in even tiny amounts. It can also facilitate sintering. Vanadium has a strong hardening effect, but this effect is particularly sensitive to the type of tempering.
| Fe | 49.1 to 59.5 | |
| Ni | 24 to 27 | |
| Cr | 13.5 to 16 | |
| Ti | 1.9 to 2.4 | |
| Mo | 1.0 to 1.5 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| V | 0.1 to 0.5 | |
| Al | 0 to 0.35 | |
| C | 0 to 0.080 | |
| P | 0 to 0.040 | |
| S | 0 to 0.030 | |
| B | 0.0010 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A638: Standard Specification for Precipitation Hardening Iron Base Superalloy Bars, Forgings, and Forging Stock for High-Temperature Service
ASTM A276: Standard Specification for Stainless Steel Bars and Shapes
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
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
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015