ASTM A231 Spring Steel vs. AISI 444 Stainless Steel
Both ASTM A231 spring steel and AISI 444 stainless steel are iron alloys. They have 79% of their average alloy composition in common. There are 30 material properties with values for both materials. Properties with values for just one material (5, in this case) are not shown.
For each property being compared, the top bar is ASTM A231 spring steel and the bottom bar is AISI 444 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 540 | |
| 190 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 14 | |
| 23 |
| Fatigue Strength, MPa | 1000 | |
| 210 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 73 | |
| 78 |
| Shear Strength, MPa | 1080 | |
| 300 |
| Tensile Strength: Ultimate (UTS), MPa | 1790 | |
| 470 |
| Tensile Strength: Yield (Proof), MPa | 1570 | |
| 310 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 290 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 930 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1460 |
| Melting Onset (Solidus), °C | 1410 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 52 | |
| 23 |
| Thermal Expansion, µm/m-K | 13 | |
| 10 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 2.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 2.5 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.3 | |
| 15 |
| Density, g/cm3 | 7.8 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 2.0 | |
| 3.4 |
| Embodied Energy, MJ/kg | 28 | |
| 47 |
| Embodied Water, L/kg | 51 | |
| 130 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 95 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 64 | |
| 17 |
| Strength to Weight: Bending, points | 42 | |
| 17 |
| Thermal Diffusivity, mm2/s | 14 | |
| 6.2 |
| Thermal Shock Resistance, points | 53 | |
| 16 |
Alloy Composition
| Carbon (C), % | 0.48 to 0.53 | |
| 0 to 0.025 |
| Chromium (Cr), % | 0.8 to 1.1 | |
| 17.5 to 19.5 |
| Iron (Fe), % | 96.7 to 97.7 | |
| 73.3 to 80.8 |
| Manganese (Mn), % | 0.7 to 0.9 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 1.8 to 2.5 |
| Nickel (Ni), % | 0 | |
| 0 to 1.0 |
| Niobium (Nb), % | 0 | |
| 0.2 to 0.8 |
| Nitrogen (N), % | 0 | |
| 0 to 0.035 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 | |
| 0.2 to 0.8 |
| Vanadium (V), % | 0.15 to 0.3 | |
| 0 |