EN 1.4550 (X6CrNiNb18-10) Stainless Steel
EN 1.4550 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the solution annealed (AT) condition. 1.4550 is the EN numeric designation for this material. X6CrNiNb18-10 is the EN chemical designation.
This material is well established: the Further Reading section below cites a number of published standards, and that list is not necessarily exhaustive.
The graph bars on the material properties cards below compare EN 1.4550 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
200
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
42 %
Fatigue Strength
210 MPa 30 x 103 psi
Impact Strength: V-Notched Charpy
90 J 67 ft-lb
Poisson's Ratio
0.28
Shear Modulus
77 GPa 11 x 106 psi
Shear Strength
430 MPa 62 x 103 psi
Tensile Strength: Ultimate (UTS)
620 MPa 90 x 103 psi
Tensile Strength: Yield (Proof)
230 MPa 34 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
480 °C 900 °F
Maximum Temperature: Mechanical
940 °C 1720 °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 8.7 BTU/h-ft-°F
Thermal Expansion
16 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
18 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
3.6 kg CO2/kg material
Embodied Energy
51 MJ/kg 22 x 103 BTU/lb
Embodied Water
140 L/kg 17 gal/lb
Common Calculations
PREN (Pitting Resistance)
18
Resilience: Ultimate (Unit Rupture Work)
210 MJ/m3
Resilience: Unit (Modulus of Resilience)
140 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
22 points
Strength to Weight: Bending
21 points
Thermal Diffusivity
4.0 mm2/s
Thermal Shock Resistance
14 points
Alloy Composition
Among wrought stainless steels, the composition of EN 1.4550 stainless steel is notable for including niobium (Nb). Niobium is primarily used to improve yield strength, particularly at elevated temperatures.
| Fe | 64.9 to 74 | |
| Cr | 17 to 19 | |
| Ni | 9.0 to 12 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| Nb | 0 to 1.0 | |
| C | 0 to 0.080 | |
| P | 0 to 0.045 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10222-5: Steel forgings for pressure purposes - Part 5: Martensitic, austenitic and austenitic-ferritic stainless steels
EN 10272: Stainless steel bars for pressure purposes
EN 10250-4: Open die steel forgings for general engineering purposes - Part 4: Stainless steels
EN 10088-2: Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes
EN 10088-3: Stainless steels - Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes
EN 10088-1: Stainless steels - Part 1: List of stainless steels
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