EN 1.4971 (X12CrCoNi21-20) Stainless Steel
EN 1.4971 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the solution annealed (AT) condition. 1.4971 is the EN numeric designation for this material. X12CrCoNi21-20 is the EN chemical designation.
It has the highest base cost among wrought austenitic stainless steels. In addition, it has the highest embodied energy and a moderately low thermal conductivity.
The graph bars on the material properties cards below compare EN 1.4971 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
240
Elastic (Young's, Tensile) Modulus
210 GPa 30 x 106 psi
Elongation at Break
34 %
Fatigue Strength
270 MPa 40 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
81 GPa 12 x 106 psi
Shear Strength
530 MPa 77 x 103 psi
Tensile Strength: Ultimate (UTS)
800 MPa 120 x 103 psi
Tensile Strength: Yield (Proof)
340 MPa 50 x 103 psi
Thermal Properties
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
570 °C 1050 °F
Maximum Temperature: Mechanical
1100 °C 2000 °F
Melting Completion (Liquidus)
1460 °C 2660 °F
Melting Onset (Solidus)
1410 °C 2560 °F
Specific Heat Capacity
450 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
13 W/m-K 7.5 BTU/h-ft-°F
Thermal Expansion
15 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
70 % relative
Density
8.4 g/cm3 520 lb/ft3
Embodied Carbon
7.6 kg CO2/kg material
Embodied Energy
110 MJ/kg 46 x 103 BTU/lb
Embodied Water
300 L/kg 35 gal/lb
Common Calculations
PREN (Pitting Resistance)
38
Resilience: Ultimate (Unit Rupture Work)
220 MJ/m3
Resilience: Unit (Modulus of Resilience)
280 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
26 points
Strength to Weight: Bending
23 points
Thermal Diffusivity
3.4 mm2/s
Thermal Shock Resistance
19 points
Alloy Composition
Among wrought stainless steels, the composition of EN 1.4971 stainless steel is notable for including cobalt (Co) and tungsten (W). Cobalt is used to improve mechanical strength at elevated temperatures. Tungsten interacts with other alloying elements to a greater extent than usual, which makes it hard to broadly characterize its effects.
| Fe | 24.3 to 37.1 | |
| Cr | 20 to 22.5 | |
| Ni | 19 to 21 | |
| Co | 18.5 to 21 | |
| Mo | 2.5 to 3.5 | |
| W | 2.0 to 3.0 | |
| Mn | 0 to 2.0 | |
| Nb | 0.75 to 1.3 | |
| Si | 0 to 1.0 | |
| N | 0.1 to 0.2 | |
| C | 0.080 to 0.16 | |
| P | 0 to 0.035 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10302: Creep resisting steels, nickel and cobalt alloys
EN 10088-1: Stainless steels - Part 1: List of stainless steels
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002
Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010