Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | ASTM A48 Class 30 Gray Cast Iron | SAE 1018 Carbon Steel |
|---|---|---|
| Material Family | Cast Iron | Steel |
| Subfamily | Gray Cast Iron | Carbon Steel |
| ASTM Designation | A48 Class 30 | — |
| UNS Designation | F12101 | — |
| SAE Designation | J431 G3000 | 1018 |
| AISI Designation | — | 1018 |
| SPECIFICATION Designation | — | SAE 1018 Carbon Steel Engineering Datasheet |
| Element | ASTM A48 Class 30 Gray Cast Iron | SAE 1018 Carbon Steel |
|---|---|---|
| C (Carbon) | 3.1 – 3.4% | 0.15 – 0.2% |
| Si (Silicon) | 1.9 – 2.3% | — |
| Mn (Manganese) | 0.6 – 0.9% | 0.6 – 0.9% |
| P (Phosphorus) | ≤ 0.12% | ≤ 0.04% |
| S (Sulfur) | ≤ 0.15% | ≤ 0.05% |
| Fe (Iron) | — | — |
| Property | ASTM A48 Class 30 Gray Cast Iron | SAE 1018 Carbon Steel |
|---|---|---|
| Density · TYPICALUnit: g/cm³ | 7.2 g/cm³ | 7.87 g/cm³ |
| Elastic Modulus · TYPICALUnit: GPa | — GPa | 205 GPa |
| Mechanical Parameter | ASTM A48 Class 30 Gray Cast IronAs-Cast (Standard Test Bar B, 30.5 mm diameter) | SAE 1018 Carbon SteelHot rolled (estimated minimum) |
|---|---|---|
| Poisson Ratio · TYPICALUnit: dimensionless | 0.26 dimensionless | 0.29 dimensionless |
| Tensile Strength · Bar · Hot rolled (estimated minimum) · MINIMUMUnit: MPa | — MPa | ≥ 399.9 MPa |
| Yield Strength · Bar · Hot rolled (estimated minimum) · MINIMUMUnit: MPa | — MPa | ≥ 220.6 MPa |
| Elongation · Bar · Hot rolled (estimated minimum) · MINIMUMUnit: % | — % | ≥ 25 % |
| Reduction Of Area · Bar · Hot rolled (estimated minimum) · MINIMUMUnit: % | — % | ≥ 50 % |
| Property | ASTM A48 Class 30 Gray Cast Iron | SAE 1018 Carbon Steel |
|---|---|---|
| Electrical Resistivity · TYPICALCategory: ELECTRICAL • Unit: nΩ·m | 680 nΩ·m | — nΩ·m |
| Thermal Conductivity · TYPICAL · 20 °CCategory: THERMAL • Unit: W/(m·K) | 48 W/(m·K) | — W/(m·K) |
| Thermal Conductivity · TYPICAL · 100 °CCategory: THERMAL • Unit: W/(m·K) | — W/(m·K) | 51.9 W/(m·K) |
| Specific Heat Capacity · TYPICALCategory: THERMAL • Unit: J/(kg·K) | 480 J/(kg·K) | 486 J/(kg·K) |
| Coefficient of Thermal Expansion · TYPICALCategory: THERMAL • Unit: µm/(m·K) | 11 µm/(m·K) | — µm/(m·K) |
| Coefficient of Thermal Expansion · TYPICAL · 100 °CCategory: THERMAL • Unit: µm/(m·K) | — µm/(m·K) | 11.7 µm/(m·K) |
| Hardness Scale | ASTM A48 Class 30 Gray Cast Iron | SAE 1018 Carbon Steel |
|---|---|---|
| HB Hardness · Bar · Hot rolled (estimated minimum) · MINIMUM | — | ≥ 116 HB |
Machinability: Excellent machinability (~90% relative to C36000 free-cutting brass). Flake graphite acts as internal lubricant and natural chip breaker. Readily turned, milled, and drilled without burr formation.
Weldability: Poor weldability. Arc welding produces brittle martensitic heat-affected zones and crack risks. Recommended repair procedure requires 250°C–350°C (480°F–660°F) preheat, nickel-iron (ENiFe-CI) electrodes, short beads with peening, and slow insulation cooling.
Formability / Cold Working: Non-deformable. Gray cast iron is inherently brittle in tension and cannot be cold or hot deformed.
Heat Treatment & Annealing: Stress relief annealing at 540°C–595°C (1000°F–1100°F) for 1–2 hours eliminates residual casting stresses and prevents distortion. Flame or induction surface hardening can achieve 50–55 HRC on slideways.