Material Selection8–10 min read
Gray, Ductile and Malleable Cast Iron: Grade Selection Explained
Graphite structure, casting section and test-coupon scope matter more than a familiar class number.
Author: Mat Grades Editorial DeskRead Guide →
ASTM A536 Grade 65-45-12 Ductile Cast Iron
Primary Designation:ASTM A536 Grade 65-45-12
Aliases:
Ductile Iron 65-45-12Nodular Iron 65-45-12SG Iron 65-45-12
Mat Grades internal verification confirms source-backed fidelity and data integrity. It does not constitute external certification or guaranteed lot conformity. Read engineering disclaimer →
Data Completeness:7 composition elements and 11 condition-specific property values cataloged.
Omitted fields represent unverified properties. "Missing is better than invented."
Key Engineering Properties
Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.
Density
7.1 g/cm³TYPICAL · temperature not stated
Thermal Conductivity
35 W/(m·K)TYPICAL · temperature not stated
Specific Heat Capacity
470 J/(kg·K)TYPICAL · temperature not stated
Composition Excerpt
C 3.5–3.8 wt%Carbon (range)
Standard Elemental Basis: RANGETensile Strength
≥ 448 MPaMINIMUM · As-Cast · temperature not stated
Engineering Summary
ASTM A536 Grade 65-45-12 is the most widely specified and produced ductile iron grade worldwide. It provides an optimal engineering balance of tensile strength (min 65 ksi / 448 MPa), yield strength (min 45 ksi / 310 MPa), and ductility (min 12% elongation) in the as-cast condition. Its microstructure comprises predominantly ferrite with 10% to 25% pearlite surrounding spherical graphite nodules. Standardized for fluid power components, automotive suspension arms, and heavy industrial machinery.
ASTM A536 Grade 65-45-12 Ductile Cast Iron Documented Applications
- ›Automotive steering knuckles, control arms, and brake calipers
- ›Hydraulic valve bodies, manifold blocks, and pump casings
- ›Water utility butterfly valves, gate valves, and pressure piping
- ›Agricultural tractor driveline yokes, brackets, and levers
- ›Wind turbine hub components and power transmission housings
Recognized Aliases
Source-backed commercial trade name and short designations cataloged in canonical data.
Ductile Iron 65-45-12Nodular Iron 65-45-12SG Iron 65-45-12
ASTM A536 Grade 65-45-12 Ductile Cast Iron Specifications & Designations
Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.
Direct Standard DesignationsDIRECT DESIGNATION
3 Primary IdentifiersScroll horizontally for full designation data
| System | Identifier | Standard System Name | Classification Notes & Provenance |
|---|---|---|---|
| ASTMPRIMARY | A536 Grade 65-45-12 | 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 | F33100 | 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 | J434 D4512 | 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 Commercial Aliases & Trade NamesCOMMON ALIAS
3 ListedScroll horizontally for full alias classifications
| Recognized Name / Alias | Classification | Technical Usage & Context |
|---|---|---|
| Ductile Iron 65-45-12 | Commercial Alias | Colloquial or commercial industry synonym |
| Nodular Iron 65-45-12 | Commercial Alias | Colloquial or commercial industry synonym |
| SG Iron 65-45-12 | Colloquial Alias | Colloquial or commercial industry synonym |
Applicable Specifications & Product Form ReferencesSPECIFICATION REFERENCE
3 Applicable StandardsScroll horizontally for full standard specifications
| Standards Body | Specification Code | Specification Title / Scope | Relationship Type |
|---|---|---|---|
| ASTM | ASTM A536 | Standard Specification for Ductile Iron Castings | Specification Reference |
| SAE | SAE J434 | Automotive Ductile (Nodular) Iron Castings (Grade D4512) | Specification Reference |
| ISO | ISO 1083 | Spheroidal graphite cast irons — Classification | Specification Reference |
Engineering Notice: Applicable specifications establish manufacturing requirements, dimensional tolerances, and test criteria for specific product forms (e.g. bus bar, wire, plate, pipe). They represent applicable technical standards, not alternative or equivalent alloy grades.
ASTM A536 Grade 65-45-12 Ductile Cast Iron Chemical Composition
Chemical Composition (Weight %) — Elemental limits and values from the cited source. Preserves exact semantic limits (minimums, maximums, and ranges).
Scroll horizontally for full elemental limits
| Element | Symbol | Atomic No. | Semantic Basis | Specified Value | Unit | Metallurgical Notes & Qualification | Data Status |
|---|---|---|---|---|---|---|---|
| Carbon | C | 0 | RANGE | 3.50 – 3.80 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Silicon | Si | 0 | RANGE | 2.20 – 2.80 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Manganese | Mn | 0 | RANGE | 0.20 – 0.50 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Phosphorus | P | 0 | MAXIMUM | ≤ 0.05 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Sulfur | S | 0 | MAXIMUM | ≤ 0.02 | wt% | Ref: ASTM International, CEN, ISO & ASM International Standards Technical Committees | VERIFIED |
| Magnesium | Mg | 0 | RANGE | 0.04 – 0.06 | wt% | Residual magnesium ensures nodularity >85%.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 |
* Elemental percentages are expressed in weight percent (wt%). Values represent applicable specification limits. Unspecified trace elements are not fabricated or assumed.Preserves exact semantic basis
Property Display UnitsSwitch between Canonical SI and Source / US Customary units:
ASTM A536 Grade 65-45-12 Ductile Cast Iron Physical Properties
Source-specific physical properties. Test temperatures are shown only where reported.
Scroll horizontally for full property parameters
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Density | 7.1 g/cm³ | TYPICAL | 7.1 g/cm³ | ASTM International, CEN & ISO Technical Committees | VERIFIED |
ASTM A536 Grade 65-45-12 Ductile Cast Iron Thermal & Thermodynamic Properties
Phase change temperatures, thermal conductivity, specific heat, mean coefficients of thermal expansion across standardized temperature ranges, and recommended thermal processing windows.
Scroll horizontally for full property parameters
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Thermal Conductivity | 35 W/(m·K) | TYPICAL | 35 W/(m·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED | |
| Specific Heat Capacity | 470 J/(kg·K) | TYPICAL | 470 J/(kg·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED | |
| Coefficient of Thermal Expansion | 11.8 µm/(m·K) | TYPICAL | 11.8 µm/(m·K) | ASTM International, CEN & ISO Technical Committees | VERIFIED |
ASTM A536 Grade 65-45-12 Ductile Cast Iron Electrical Properties
Electrical conductivity and resistivity in their reported units and conditions.
Scroll horizontally for full property parameters
| Property Parameter | Canonical SI Value | Semantic Basis | Test Temperature / Context Range | Source Raw Reference | Source Reference | Status |
|---|---|---|---|---|---|---|
| Electrical Resistivity | 560 nΩ·m | TYPICAL | 560 nΩ·m | ASTM International, CEN & ISO Technical Committees | VERIFIED |
ASTM A536 Grade 65-45-12 Ductile Cast Iron Mechanical Properties
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.
Elastic & Baseline Mechanical ConstantsSource-specific measurement conditions
Poisson Ratio
0.28 dimensionless
Showing 3 of 3 conditions
Scroll horizontally for all conditions & tempers
| Product Form | Temper / Condition | Section Size | Tensile (UTS) | Yield Strength | Elongation | Shear Strength | Fatigue Strength | Hardness (Scales Preserved) | Status |
|---|---|---|---|---|---|---|---|---|---|
| Separately cast test coupon | As-CastSource values and qualifiersUltimate Tensile Strength: ≥ 448 MPa (MINIMUM)Governing minimum tensile strength per ASTM A536 Grade 65-45-12 (65 ksi = 448 MPa).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 | — | ≥ 448 MPa | — | — | — | — | — | VERIFIED |
| Standard Product Form | As-CastSource values and qualifiers0.2% Offset Yield Strength: ≥ 310 MPa (MINIMUM)Governing minimum 0.2% offset yield strength per ASTM A536 (45 ksi = 310 MPa).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 Elongation at Break (50 mm): ≥ 12 % (MINIMUM)Governing minimum tensile elongation in 2 inches (50 mm) is 12%.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 | — | — | ≥ 310 MPa | ≥ 12 % | — | — | — | VERIFIED |
| Standard Product Form | As-CastSource values and qualifiers | — | — | — | — | — | — | 156–217 HBW | VERIFIED |
Hardness Integrity Notice: Rockwell B (HRB), Rockwell F (HRF), and Superficial 30T (HR30T) scales are reported on their measured scales without cross-scale mathematical conversion.
Source: See fact-level citations
ASTM A536 Grade 65-45-12 Ductile Cast Iron Processing & Fabrication
Machining, joining, forming, and thermal processing ratings cataloged from the cited authoritative technical reference.
Machinability
Very good machinability (~80% relative to C36000 baseline). Low cutting forces, good tool life, and smooth surface finishes.
Weldability & Joining
Moderately weldable with qualified procedures. Preheating to 200°C–250°C and nickel-iron (ENiFe-CI) filler wire are required to prevent hard heat-affected zones.
Heat Treatment & Working Ranges
Typically utilized in the as-cast condition. Can be full annealed at 870°C for maximum ductility or normalized at 900°C for increased strength.
Forming & Cold Working
Limited localized forming (coining, staking) feasible due to 12% elongation.
Practical Engineering & Fabrication Notes
By Mat Grades Editorial Desk · Updated 2026-11-14. Use alongside the specified product standard and supplier certificate.
Machining & shop-floor behavior
The cataloged machining note for ASTM A536 Grade 65-45-12 Ductile Cast Iron states: Very good machinability (~80% relative to C36000 baseline). Low cutting forces, good tool life, and smooth surface finishes. A relevant hardness example is HBW Hardness: 156–217 HBW (range; As-Cast). Use that supplied condition for a trial of the difficult feature. Record tool changes, burr removal, unclamped dimensions and accepted parts per hour. Relative machinability ratings from different reference scales should not be compared as if they were one common test.
Weldability, brazing & joining
The available joining assessment states: Moderately weldable with qualified procedures. Preheating to 200°C–250°C and nickel-iron (ENiFe-CI) filler wire are required to prevent hard heat-affected zones. The first cataloged strength example is Ultimate Tensile Strength: minimum 448 MPa (minimum; As-Cast, Separately cast test coupon). Assess the final part after joining or thermal processing. Include distortion, cleanup and inspection in the quotation. A material designation or favorable process rating is a starting point for qualification, not evidence that an untested joint meets the drawing.
Corrosion & service environment
Consider moisture, coating, local tensile stress and impact as well as the cast-iron family. Surface protection does not repair porosity or a highly stressed transition. Casting section and sampling arrangement affect how coupon evidence relates to the finished component; keep those limits visible in the approval. The recorded thermal example is Thermal Conductivity: 35 W/(m·K) (typical; additional condition not stated). State the exposure and inspection access in the design record so that a change of installation or cleaning method triggers a review. The selected composition entries are C 3.5–3.8 wt%, Si 2.2–2.8 wt%, Mn 0.2–0.5 wt%. Chemistry documents identity; it does not establish fluid compatibility.
Selection trade-offs & applications
Use ASTM A536 Grade 65-45-12, UNS F33100, SAE J434 D4512 to identify the candidate, then specify the product form and delivered condition separately. The catalog lists Automotive steering knuckles, control arms, and brake calipers as an application example. The related candidate ASTM A536 Grade 80-55-06 Ductile Cast Iron is linked for comparison; its commonly compared relationship must be checked before substitution. Compare the complete route through machining, joining, finish and inspection. Keep the certificate, required test location and acceptance criteria with the first-article record. A later change of grade, condition or source should be assessed against that same requirement.
Technical references: ASTM International, CEN, ISO & ASM International Standards Technical Committees
ASTM A536 Grade 65-45-12 Ductile Cast Iron Equivalent & Comparable Grades
Comparable Grades & Cross-References: Carefully classified cross-reference relationships for ASTM A536 Grade 65-45-12 Ductile Cast Iron. Comparable does not mean equivalent.
Scroll horizontally for relationship classifications & comparisons
| Related Material | Family | Relationship Classification | Metallurgical Notes & Differences | Status | Action |
|---|---|---|---|---|---|
| ASTM A536 Grade 80-55-06 Ductile Cast Iron | Cast Iron | Commonly Compared | Tradeoff between ductility and strength: 65-45-12 provides double the elongation (12% vs 6%) and superior impact resistance, while 80-55-06 offers 23% higher yield strength (379 vs 310 MPa) and increased wear resistance due to higher pearlite fraction.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost). | VERIFIED | |
| EN-GJS-400-15 Ductile Cast Iron | Cast Iron | Approximate Equivalent | EN-GJS-400-15 (min 400 MPa UTS, 250 MPa YS, 15% elongation) is the nearest European counterpart to ASTM A536 65-45-12 (min 448 MPa UTS, 310 MPa YS, 12% elongation). Both serve general mechanical engineering and pressure vessel roles.Engineering substitution review required. Design calculations must verify temper, formability, and corrosion limits before specifying as a direct replacement. | VERIFIED |
Related Engineering & Metallurgy Guides
Contextual technical guides explaining degradation mechanisms, testing methodologies, and selection criteria relevant to ASTM A536 Grade 65-45-12 Ductile Cast Iron.
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How to Remove Rust From Cast Iron: Methods, Science & Prevention
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Author: Mat Grades Editorial DeskRead Guide →
Sources
Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.
ASTM International, CEN & ISO Technical CommitteesStandard 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)
STANDARDS ORG
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).
Issuing Body: ASTM International, CEN, ISO & ASM International Standards Technical CommitteesRevision: ASTM A48/A48M-22 / ASTM A536-84(2024) / EN 1561:2020 / EN 1563:2018 / ISO 185:2020 / ISO 1083:2018View Source Record ↗
Intellectual Property & Provenance Notice: Mat Grades cites technical literature from recognized industry associations and standards organizations. Underlying technical standards and publication data remain the intellectual property of their respective issuing organizations.