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Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.
ASTM A48 Class 30 is the global reference standard for general-purpose engineering gray cast iron. Engineered with a predominantly pearlitic matrix containing finely dispersed Type A graphite flakes, it provides an outstanding combination of moderate tensile strength (min 30 ksi / 207 MPa), high compressive strength (~750 MPa), exceptional vibration damping, resistance to frictional wear, and dimensional stability. It is the premier alloy for engine cylinder blocks, machine tool structures, and automotive brake discs.
Source-backed commercial trade name and short designations cataloged in canonical data.
Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.
| System | Identifier | Standard System Name | Classification Notes & Provenance |
|---|---|---|---|
| ASTMPRIMARY | A48 Class 30 | ASTM International | —Ref: Standard Specifications for Gray and Ductile Cast Iron (ASTM A48/A48M, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, ASM Handbook Vol 1) |
| UNS | F12101 | Unified Numbering System | —Ref: Standard Specifications for Gray and Ductile Cast Iron (ASTM A48/A48M, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, ASM Handbook Vol 1) |
| SAE | J431 G3000 | SAE International | —Ref: Standard Specifications for Gray and Ductile Cast Iron (ASTM A48/A48M, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, ASM Handbook Vol 1) |
| Recognized Name / Alias | Classification | Technical Usage & Context |
|---|---|---|
| Class 30 Gray Iron | Commercial Alias | Colloquial or commercial industry synonym |
| SAE G3000 Brake Rotor Iron | Commercial Alias | Colloquial or commercial industry synonym |
| Grade 30 Gray Cast Iron | Colloquial Alias | Colloquial or commercial industry synonym |
| Standards Body | Specification Code | Specification Title / Scope | Relationship Type |
|---|---|---|---|
| ASTM | ASTM A48 / A48M | Standard Specification for Gray Iron Castings | Specification Reference |
| SAE | SAE J431 | Automotive Gray Iron Castings (Grade G3000) | Specification Reference |
| ISO | ISO 185 | Grey cast irons — Classification | Specification Reference |
Chemical Composition (Weight %) — Elemental limits and values from the cited source. Preserves exact semantic limits (minimums, maximums, and ranges).
| Element | Symbol | Atomic No. | Semantic Basis | Specified Value | Unit | Metallurgical Notes & Qualification | Data Status |
|---|---|---|---|---|---|---|---|
| Carbon | C | 0 | RANGE | 3.10 – 3.40 | wt% | Carbon adjusted for fully pearlitic matrix in standard section sizes.Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Silicon | Si | 0 | RANGE | 1.90 – 2.30 | wt% | Controls graphitization without promoting free ferrite.Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Manganese | Mn | 0 | RANGE | 0.60 – 0.90 | wt% | Stabilizes pearlite matrix structure.Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Phosphorus | P | 0 | MAXIMUM | ≤ 0.12 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Sulfur | S | 0 | MAXIMUM | ≤ 0.15 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Iron | Fe | 0 | REMAINDER | Remainder | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
Source-specific physical properties. Test temperatures are shown only where reported.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Density | 7.2 g/cm³ | TYPICAL | 7.2 g/cm³ | ASTM International, CEN & ISO Technical Committees | VERIFIED |
Phase change temperatures, thermal conductivity, specific heat, mean coefficients of thermal expansion across standardized temperature ranges, and recommended thermal processing windows.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Thermal Conductivity | 48 W/(m·K) | TYPICAL | Test Temp: 20 °C | 48 W/(m·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED |
| Specific Heat Capacity | 480 J/(kg·K) | TYPICAL | 480 J/(kg·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED | |
| Coefficient of Thermal Expansion | 11 µm/(m·K) | TYPICAL | 11 µm/(m·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED |
Electrical conductivity and resistivity in their reported units and conditions.
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Electrical Resistivity | 680 nΩ·m | TYPICAL | 680 nΩ·m | ASTM International, CEN & ISO Technical Committees | VERIFIED |
Contextual Mechanical Properties & Tempers: Engineering strength, ductility, and hardness values grouped by product form, temper, and section thickness. Mechanical properties are contextual and not isotropic averages.
| Product Form | Temper / Condition | Section Size | Tensile (UTS) | Yield Strength | Elongation | Shear Strength | Fatigue Strength | Hardness (Scales Preserved) | Status |
|---|---|---|---|---|---|---|---|---|---|
| Standard Product Form | As-CastSource values and qualifiersUltimate Tensile Strength: ≥ 207 MPa (MINIMUM)Governing specification minimum per ASTM A48 Class 30 (30 ksi = 207 MPa). Gray iron exhibits non-linear stress-strain behavior with no yield point.ASTM International, CEN, ISO & ASM International Standards Technical Committees — ASTM A48, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, ASM Handbook Vol 1 | 30.5 mm (1.2 in.) diameter Test Bar B | ≥ 207 MPa | — | — | — | — | — | VERIFIED |
| Standard Product Form | As-CastSource values and qualifiersModulus of Elasticity: 100 GPa (TYPICAL)Secant modulus at 25% tensile strength.ASTM International, CEN, ISO & ASM International Standards Technical Committees — ASTM A48, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, ASM Handbook Vol 1 | — | — | — | — | — | — | — | VERIFIED |
| Standard Product Form | As-CastSource values and qualifiers | — | — | — | — | — | — | 175–225 HBW | VERIFIED |
Machining, joining, forming, and thermal processing ratings cataloged from the cited authoritative technical reference.
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.
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.
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.
Non-deformable. Gray cast iron is inherently brittle in tension and cannot be cold or hot deformed.
Comparable Grades & Cross-References: Carefully classified cross-reference relationships for ASTM A48 Class 30 Gray Cast Iron. Comparable does not mean equivalent.
| Related Material | Family | Relationship Classification | Metallurgical Notes & Differences | Status | Action |
|---|---|---|---|---|---|
| ASTM A536 Grade 65-45-12 Ductile Cast Iron | Cast Iron | Commonly Compared | Fundamental cast iron selection comparison: Class 30 Gray Iron provides 3x higher vibration damping, superior thermal conductivity (48 vs 35 W/(m·K)), and lower casting cost, but 65-45-12 Ductile Iron provides true tensile ductility (12% elongation), specified yield strength (310 MPa), and high impact shock resistance.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost). | VERIFIED | Side-by-Side Compare → |
| EN-GJL-200 Gray Cast Iron | Cast Iron | Approximate Equivalent | EN-GJL-200 specifies min 200 MPa tensile strength on 15–30 mm wall thickness, closely approximating ASTM A48 Class 30 (min 207 MPa on 30.5 mm Test Bar B). However, EN 1561 incorporates mandatory wall-thickness derating tables not present in ASTM A48.Engineering substitution review required. Design calculations must verify temper, formability, and corrosion limits before specifying as a direct replacement. | VERIFIED | Side-by-Side Compare → |
| SAE 1018 Carbon Steel | Steel | Commonly Compared | Class 30 Gray Iron offers net-shape casting capability, superior vibration damping, higher compressive strength (~750 vs ~400 MPa), and better machinability for heavy machine bases, whereas SAE 1018 steel provides high tensile elongation (~25%), yield strength, and structural weldability.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost). | VERIFIED | Side-by-Side Compare → |
Contextual technical guides explaining degradation mechanisms, testing methodologies, and selection criteria relevant to ASTM A48 Class 30 Gray Cast Iron.
Cast iron is an indispensable alloy family renowned for superior vibration damping and castability, but its iron matrix and carbon microstructure make it susceptible to atmospheric rust. Restoring rusted cast iron requires understanding how mechanical and chemical methods interact with the underlying metal.
Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.
Authoritative foundry data harmonized across ASTM A48, ASTM A536, EN 1561, EN 1563, ISO 185, ISO 1083, SAE J431, SAE J434, and ASM International Handbook Volume 1 (Properties and Selection: Irons, Steels, and High-Performance Alloys).