Grade FDC Spring Steel
Grade FDC steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the hardened (H) condition.
It has a fairly low electrical conductivity among EN wrought alloy steels. In addition, it has a moderately low embodied energy and a very low base cost.
The graph bars on the material properties cards below compare grade FDC 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
Brinell Hardness
510
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Poisson's Ratio
0.29
Reduction in Area
42 %
Shear Modulus
80 GPa 12 x 106 psi
Tensile Strength: Ultimate (UTS)
1680 MPa 240 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
400 °C 760 °F
Melting Completion (Liquidus)
1450 °C 2650 °F
Melting Onset (Solidus)
1410 °C 2570 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
51 W/m-K 29 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.1 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.2 % IACS
Otherwise Unclassified Properties
Base Metal Price
1.9 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.4 kg CO2/kg material
Embodied Energy
19 MJ/kg 8.1 x 103 BTU/lb
Embodied Water
47 L/kg 5.6 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
60 points
Strength to Weight: Bending
40 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
50 points
Alloy Composition
Among alloy steels, the composition of grade FDC steel is notable for including copper (Cu). Copper is used to improve corrosion resistance, and to add at least some degree of precipitation hardenability.
| Fe | 98 to 99.4 | |
| Mn | 0.5 to 1.2 | |
| C | 0.6 to 0.75 | |
| Si | 0.1 to 0.35 | |
| Cr | 0 to 0.3 | |
| Cu | 0 to 0.12 | |
| P | 0 to 0.030 | |
| S | 0 to 0.025 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 10270-2: Steel wire for mechanical spring - Part 2: Oil hardened and tempered spring steel wire
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015