cast iron
Enable an agent to identify cast iron by composition and microstructure, assess its material condition, and judge suitability for a proposed use, treatment, repair, or recovery route.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to identify cast iron by composition and microstructure, assess its material condition, and judge suitability for a proposed use, treatment, repair, or recovery route.
Cast iron is a family of iron-carbon alloys, usually also containing silicon, with carbon content generally above about 2% by mass, whose properties depend strongly on whether carbon occurs as graphite or carbides and on the surrounding metallic microstructure.
It can be Classify a specimen or lot provisionally and identify the tests needed to resolve its cast-iron family or grade.; Compare verified material properties with a proposed mechanical, thermal, wear, or corrosion requirement.; Select inspection and sampling approaches that account for graphite structure, casting section, and likely defects.; Assess candidate machining, heat-treatment, and joining routes against the identified grade and material condition.; Determine whether repair, continued service, reuse, or segregation for recycling requires additional evidence..
Distinguishing features
Establish alloy-family identity from composition and metallurgical evidence: being cast into a shape does not distinguish cast iron from cast steel.
Distinguish gray, ductile, compacted-graphite, white, and malleable irons through graphite or carbide form together with processing history; these names are not interchangeable grades.
Distinguish cast iron from wrought iron using carbon-bearing phases and matrix structure rather than surface appearance or the object's age.
Distinguish a finished cast-iron material from pig-iron feedstock through its material specification, processing history, and intended role; similar bulk chemistry alone may not settle the boundary.
Treat magnetic response, fracture appearance, and spark testing as supporting observations whose ability to establish a specific grade requires verification.
Scope
+ Alloy composition, grade designation, and evidence connecting a specimen or material lot to that grade
+ Graphite morphology, carbide distribution, matrix structure, and relevant casting defects
+ Mechanical, thermal, and corrosion behavior under stated conditions
+ As-cast, heat-treated, machined, repaired, and service-degraded material states
+ Material suitability for casting, machining, joining, inspection, reuse, and recycling
- Component geometry, load-path design, and complete product certification
- Foundry equipment, production scheduling, and detailed casting-process control
- Steel, wrought iron, and pig iron as separately identified material categories
- Cookware seasoning systems, food preparation, and appliance operation
- Standalone coatings, lubricants, and other materials applied to cast iron
Characteristics
- Alloy composition
- Mass percent of carbon, silicon, manganese, phosphorus, sulfur, and relevant alloying or residual elements; analytical method and uncertainty Composition affects solidification, graphite formation, carbide formation, and achievable properties.
- Cast-iron family and grade
- Gray, ductile, compacted-graphite, white, malleable, other specified family, or unresolved; grade designation with standard and edition The broad label cast iron is insufficient for predicting behavior or authorizing substitution.
- Graphite morphology and distribution
- Morphology classification, graphite size and distribution, nodularity percentage or particle count where applicable; method and sampling location Graphite form strongly influences strength, ductility, crack initiation, and thermal behavior.
- Matrix and carbide structure
- Ferritic, pearlitic, ausferritic, martensitic, carbide-rich, mixed, or other verified structure Materials with similar graphite form can have different hardness, toughness, and machining behavior.
- Processing and treatment state
- As-cast, annealed, normalized, quenched and tempered, austempered, stress-relieved, locally chilled, repaired, other documented state, or unknown Processing history determines whether published grade properties plausibly describe the material being assessed.
- Mechanical test results
- Strength in MPa, elongation in percent, hardness on a named scale, and toughness or fatigue results with test method, temperature, specimen origin, and orientation Acceptance must rely on applicable evidence rather than a generic assumption that all cast iron behaves alike.
- Thermal response
- Thermal conductivity in W/(m·K), expansion coefficient in 1/K, heat capacity in J/(kg·K), and solidification or melting interval in °C; conditions stated Heat transfer, dimensional change, and thermal cycling constrain service and processing.
- Defect and degradation condition
- Cracks, porosity, shrinkage, inclusions, wear, corrosion, graphitic corrosion, or no relevant indication detected; extent and inspection coverage Local damage or metal loss can invalidate suitability even when nominal grade is acceptable.
- Evidence traceability
- Links among heat or lot, specimen, component location, certificate, test report, treatment record, and inspection record An agent must know whether evidence describes the actual material, a representative coupon, or only a nominal grade.
- Exposure-relevant physical form
- Solid casting, chips, fines, dust, molten material, or process-generated fume; associated composition and contamination Handling and exposure controls depend on physical form and processing, not solely on the alloy name.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 19 findings · 29 questions.
Alloy identity and evidence Establish what cast iron is present and how confidently its identity is known.
Cast iron covers materially different alloy families, and a product label or casting method cannot establish grade.
Composition and family boundary
Connect measured chemistry with the applicable cast-iron classification.
Composition-supported identity
Record chemistry and classification evidence without imposing an unverified universal carbon cutoff.
- What measured composition and metallurgical criteria support identifying this material as cast iron rather than cast steel, wrought iron, or feedstock pig iron? boundary
- Which analytical method, sampling location, and uncertainty accompany the carbon, silicon, alloying-element, and residual-element results? measurement
Grade and lot traceability
Link grade claims and property evidence to the material being assessed.
Grade claim applicability
Separate a verified grade assignment from an approximate trade name or inferred equivalent.
- Which specification, edition, designation, and certificate establish the claimed grade? provenance
- Do the chemistry and test reports refer to this heat, this casting, an attached coupon, or a separately cast specimen? provenance
Graphite, matrix, and solidification Describe the internal structure that differentiates cast-iron families and local material behavior.
Bulk composition alone cannot establish graphite form, matrix condition, or section-dependent casting structure.
Graphite and carbide form
Identify the form and distribution of carbon-bearing constituents.
Carbon-phase identification
Capture observed graphite morphology and carbide presence using an explicit examination method.
- Does metallography show flakes, spheroids, compacted graphite, temper-carbon aggregates, substantial carbides, or a mixed structure? measurement
- Which sampling locations and classification method support the reported graphite size, distribution, nodularity, or carbide fraction? measurement
Matrix and section variation
Relate matrix structure and local variation to solidification and treatment history.
Local structure representativeness
Determine whether inspected sections represent the regions relevant to the proposed use.
- What matrix constituents, chilled regions, or segregation occur at surfaces, thin sections, and heavier sections? measurement
- What cooling, inoculation, graphite-modification, or heat-treatment records help explain the observed structure? provenance
Service property envelope Connect measured cast-iron properties to the conditions under which they support a use decision.
Strength, ductility, wear resistance, damping, and thermal response vary across grades and material states.
Mechanical and contact response
Assess resistance to applied loads, repeated loading, impact, and contact damage.
Mechanical evidence for use
Match material test evidence to the relevant failure modes rather than relying on hardness alone.
- Which tensile, compressive, elongation, fatigue, impact, or fracture measurements address the intended loading conditions? measurement
- For sliding or abrasive contact, what counterface, lubrication, contact pressure, and test conditions support the wear assessment? boundary
Thermal and environmental response
Assess temperature-dependent behavior and interaction with the service environment.
Environment-specific suitability
Define the evidence needed for exposure to heat, thermal cycling, and corrosive media.
- What temperature-dependent conductivity, expansion, strength, and thermal-cycling evidence applies to this grade and condition? measurement
- Which fluid chemistry, moisture, temperature, flow, and galvanic contacts define the corrosion assessment? boundary
Integrity and material transformation Assess defects, service damage, and the consequences of machining, heat treatment, or repair.
Cast-iron structure affects both defect detection and the likelihood that an intervention creates cracks or undesirable local structures.
Defects and degradation
Characterize integrity loss and the limits of inspection evidence.
Remaining sound material
Distinguish external appearance from evidence of structurally effective material.
- What inspection establishes the location and extent of cracks, shrinkage, porosity, inclusions, wear, or graphitic corrosion? measurement
- How do graphite structure, surface condition, and casting geometry limit the selected inspection method and its coverage? boundary
Machining, treatment, and joining
Evaluate proposed transformations against the identified alloy and its current condition.
Intervention compatibility
Record the evidence and acceptance criteria needed before changing the material state.
- How do graphite form, carbide content, hardness, residual stress, and contamination constrain the proposed machining or joining route? action
- What qualified procedure and post-intervention inspection or testing would establish acceptable structure, cracking risk, and properties after repair or heat treatment? action
Handling and material recovery Track the material-specific information needed for handling, reuse, and remelting.
A solid casting, machining dust, and alloyed scrap require different evidence even when all originate from cast iron.
Form-specific exposure
Identify hazards using actual physical form, alloy constituents, and associated substances.
Applicable hazard identity
Avoid assigning a single chemical identifier or hazard classification to the entire cast-iron family.
- Which supplier safety information and jurisdictional classification apply to this composition and physical form? provenance
- Which alloy constituents, coatings, residues, or process-generated dusts and fumes require exposure assessment for the proposed operation? action
Reuse and remelting
Separate evidence for retaining material in service from evidence for accepting it as furnace feedstock.
Recovery route eligibility
Determine what identity, condition, and contamination evidence supports a recovery route.
- What grade traceability and integrity evidence are needed to reuse this material in the proposed application? action
- Which alloying elements, residuals, mixed scrap, or surface contamination constrain segregation and acceptance for the intended remelt? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This is recalled knowledge without source verification; check standard editions, scope and grade requirements before specification or procurement.
- Composition and density ranges describe common grades, not defining limits; alloyed and special-purpose irons can fall outside them.
- Cast iron is an alloy family without one universal chemical identifier, melting point, strength or hazard classification; establish grade, microstructure, product form and exposure conditions first.
- Which of these check these first hold for the sense of cast iron this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Grey cast iron
- White cast iron
- Ductile or spheroidal graphite cast iron
- Malleable cast iron
- Compacted graphite cast iron
- Which of these kinds and varieties hold for the sense of cast iron this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- ASTM material specification and grade - ASTM A48 Class 30; ASTM A536 65-45-12 - Examples identify grey and ductile iron grades respectively; they are material designations, not chemical substance identifiers.
- European cast iron designation - EN-GJL-250; EN-GJS-400-15 - Examples designate flake graphite and spheroidal graphite cast irons respectively, with numerical mechanical-property requirements.
- Which of these identifiers and schemes hold for the sense of cast iron this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- ASTM International ASTM A48/A48M: grey iron castings.
- ASTM International ASTM A536: ductile iron castings.
- ASTM International ASTM A47/A47M: ferritic malleable iron castings.
- International Organization for Standardization ISO 185: classification of grey cast irons.
- International Organization for Standardization ISO 1083: classification of spheroidal graphite cast irons.
- Which of these standards and regulation hold for the sense of cast iron this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Engine blocks and cylinder heads.
- Machine tool beds and equipment housings, particularly where vibration damping is useful.
- Ductile iron water pipes and fittings.
- Brake discs and drums.
- Cookware, including skillets and cooking pots.
- Which of these real-world use hold for the sense of cast iron this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Carbon mass fraction in common grades - 2-4 - %
- Silicon mass fraction in common grades - 1-3 - %
- Density of common grades near room temperature - 6.9-7.4 - g/cm³
- Which of these typical measurements hold for the sense of cast iron this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Brittle fracture under tension or impact is especially significant in grey and white irons; ductile and malleable irons have different toughness and ductility.
- Casting porosity, shrinkage cavities and inclusions can reduce load capacity and initiate fatigue cracks.
- Thermal shock and constrained thermal expansion can cause cracking.
- Corrosion can cause section loss; graphitic corrosion can leave a weak graphite-rich residue in susceptible irons.
- Foundry and finishing operations can expose workers to molten metal, metal dust and fumes, and respirable crystalline silica from silica-containing moulding materials.
- Which of these failure modes and hazards hold for the sense of cast iron this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- North American procurement commonly uses ASTM specifications; European procurement commonly uses EN designations. Matching grade labels alone does not establish equivalence.
- Both 'gray iron' and 'grey iron' are used; 'ductile iron', 'nodular iron' and 'spheroidal graphite iron' refer to the same broad variety.
- Which of these regional variation hold for the sense of cast iron this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Steel - Steel generally has less than about 2% carbon by mass; the boundary is conventional and needs qualification for some alloy systems.
- Cast steel - Cast steel is steel shaped by casting; casting a ferrous alloy does not by itself make it cast iron.
- Wrought iron - Wrought iron has very low carbon and characteristic slag inclusions, unlike the carbon-rich microstructures of cast iron.
- Pig iron - Pig iron is a high-carbon ironmaking product commonly used as melting feedstock; it is not synonymous with a finished cast iron grade.
- Cast iron cookware - Cookware is a product made from cast iron; its geometry, coatings and service requirements are additional to the material definition.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of cast iron this model covers, and on what evidence? provenance
What the second pass must settle
- Which authoritative definitions and composition boundaries should govern the cast-iron family, including highly alloyed exceptions and its boundary with cast steel?
- Which grade standards and editions should anchor classification, and where do apparent cross-standard equivalents require additional evidence?
- Which sampling and metallographic methods best establish representative graphite, matrix, and defect conditions across different casting sections?
- Which validated property datasets cover the intended grades, heat treatments, section sizes, temperatures, and corrosion environments?
- Which chemical identifiers, safety classifications, exposure limits, and recovery requirements apply to particular cast-iron compositions and physical forms in the relevant jurisdictions?