Technical comparative
charts
Mechanical properties of iron at room temperature
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Tensile strength (Ksi) [U] | 25 to 50 | 60 to 100 | 70 | 90 |
| Yield strength (Ksi) | - | 40 to 60 | 45 | 60 |
| Elongation (%) [EL] | <1 | 20 | 26 | 23 |
| Hardness (BHN) | 160 - 210 | 170 - 220 | 120 - 160 | 180 - 220 |
| Charpy test - V-shaped notch [J] at 20°C | 1.5 - 7 | 12 - 20 | 25 - 50 | 60 - 120 |
| Crack growth resistance (MPa m) | 11 - 19 | 45 - 100 | 50 - 175 | 50 - 175 |
Castability of iron
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Ability to fill thin and extended cavities | Excellent | Good | Average | Average |
| Shrinkage free hardening | Excellent | Good | Bad | Bad |
Behavior of iron according to temperature gradients
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Basic thermal resistance parameter (Eα/k) | 24 | 67 | 55 | 89 |
| Basic thermal resistance parameter (Eα/k) | 9 | 7 | 9 | 7 |
| Estimated thermal stress 1200°F | Good | Average | Average / Good | Average / Good |
| Thermal shock | Bad / Average | Average | Good | Good |
| Thermal constraints Mechanical endurance at 1200°F | Bad / Average | Average | Good | Good / Very good |
| High temperature resistance (Ksi) | 4 | 6 | 9 | 14 / 30 |
Iron resistance to oxidation and scaling
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Resistance to oxidation / Scaling | Average | Good | Good | Good |
Dimensional stability of iron at high temperature
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Shape stability | Excellent | Average | Bad | Average |
| Creep, (%/hr at 800°F, 25 Ksi) | Excellent .001 - .01 | Average .02 - .2 | Bad / Average .05 - .5 | Bad / Average .005 - .05 |
| Resistance to swelling | Bad | Good | Good / Very good | Very good |
Degradation of mechanical properties of iron according to temperature
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Degradation of tensile strength at 750°F | <15% | <15% | <15% | <15% |
| Degradation of yield strength | - | <15% | <15% | <15% |
| Degradation of elongation strength at 750°F | - | <15% | <15% | <15% |
| Degradation of resistance at 1100°F | <50% | <50% | >90% | >50% |
| Degradation of resistance at 1300°F | >75% | >75% | >95% | >80% |
| QI | < 500 | 38000 | 55000 | 50000 / 85000 |
Other manufacturing characteristics of iron
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Machinability | Excellent | Good | Average | Average |
| Formability | Nil | Bad | Excellent | Average |
| Hardenability | Very good | Excellent | Bad | Bad / Low |
| Weldability | Bad | Bad | Excellent | Good |
Physical properties of iron at room temperature
| Grey Iron | Ductile Iron | Low carbon Steel Casting | Low Alloy Steel Casting | |
|---|---|---|---|---|
| Density (lbs/in³) | 0.26 | 0.26 | 0.26 | 0.28 |
| Poisson's ratio[ט] | 0.28 | 0.28 | 0.3 | 0.3 |
| Modulus of elasticity(Tension) (Psi) [E] | 13000000 | 26000000 | 30000000 | 30000000 |
| Modulus of rigidity (Shearing) (Psi) [G] | 5800000 | 9800000 | 11500000 | 11500000 |
| Thermal conductivity (BTU/Hr/ft²/inch/°F) [k](Cu=2700 | 325 | 250 | 350 | 225 |
| Thermal expansion coefficient(/°F) [a] | 5.8 x 10-6 | 6.5 X 10-6 | 6.5 X 10-6 | 6.7 X 10-6 |
| Damping capacity | 40 to 125 | 3 to 10 | 1 to 2 | 1 to 2 |
| Electrical resistivity(µ Ohm . Cm) [ρ] (Cu =1.67) | 80 to 100 | 40 to 60 | 12 | 15 |
| Magnetic properties (KiloGauss/Oersteds@100 Oersteds | 10 | 14 | 16 | 16 |
| Pattern-making shrinkage (%) | 0.83 | 1.04 | 1.56 | 2.08 |
