Core Hardened (+CH) 1.7220 Steel
EN 1.7220 +CH steel is EN 1.7220 steel in the core hardened (CH) condition. It has the second highest strength compared to the other variants of EN 1.7220 steel. The graph bars on the material properties cards below compare EN 1.7220 +CH steel to: EN wrought alloy 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 27 x 106 psi
Poisson's Ratio
0.29
Rockwell C Hardness
45
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
1460 MPa 210 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
420 °C 800 °F
Melting Completion (Liquidus)
1460 °C 2660 °F
Melting Onset (Solidus)
1420 °C 2590 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
44 W/m-K 25 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.3 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.4 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.5 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
20 MJ/kg 8.5 x 103 BTU/lb
Embodied Water
51 L/kg 6.1 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
52 points
Strength to Weight: Bending
36 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
43 points
Alloy Composition
| Fe | 96.8 to 98.1 | |
| Cr | 0.9 to 1.2 | |
| Mn | 0.6 to 0.9 | |
| C | 0.3 to 0.37 | |
| Mo | 0.15 to 0.3 | |
| Si | 0 to 0.4 | |
| P | 0 to 0.035 | |
| S | 0 to 0.035 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
EN 10250-3: Open die steel forgings for general engineering purposes - Part 3: Alloy special steels
Welding Metallurgy, 2nd ed., Sindo Kou, 2003
EN 10263-4: Steel rod, bars and wire for cold heading and cold extrusion - Part 4: Technical delivery conditions for steels for quenching and tempering
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015