| Material options | Gray iron contains flake-shaped graphite; ductile iron contains graphite nodules. Ductile iron generally offers greater tensile strength and ductility than gray iron, while properties depend on grade and section size. | Specify the required material grade and applicable standard. Common specifications include ASTM A48 for gray iron, ASTM A536 for ductile iron, EN 1561 for gray iron, and EN 1563 for ductile iron. |
| Strength and service performance | Cast iron properties vary by composition, casting process, heat treatment, and casting geometry. A material designation alone does not establish that every section of a casting will have identical properties. | Review mechanical-property requirements, test-piece provisions, operating loads, and the supplier’s inspection plan. Request evidence that testing represents the specified material and production process. |
| Vibration damping | Gray iron’s graphite-flake structure gives it useful vibration-damping characteristics compared with many steel grades. | Consider gray iron for suitable machine bases, housings, and similar components where damping matters. Confirm that its strength and impact limitations are acceptable for the application. |
| Shape and design flexibility | Casting can produce complex shapes, internal passages, and substantial sections. Depending on design and production volume, a casting may reduce the need to assemble multiple fabricated parts. | Review draft, wall thickness transitions, cores, machining allowances, and likely shrinkage or distortion with the foundry before finalizing the design. |
| Machining and finished dimensions | Machinability depends on the iron grade, microstructure, hardness, and cutting conditions. Cast surfaces and as-cast dimensions do not automatically meet precision-machined requirements. | Identify datum surfaces, tolerances, surface-finish requirements, and which features will be machined. Agree on dimensional inspection methods for critical features. |
| Corrosion protection | Ordinary unalloyed cast iron is not stainless steel and can corrode in wet or corrosive environments. Coatings and other protection can affect both performance and maintenance needs. | Specify the service environment, coating system, coverage, and acceptance criteria. Include coating inspection and repair requirements where relevant. |
| Total landed cost | Tooling, casting complexity, alloy or grade, order quantity, yield, machining, finishing, inspection, and freight all affect total cost. Cast iron is not automatically the lowest-cost choice for every design or order size. | Compare quotations on the same technical scope, including tooling ownership, sampling, testing, packaging, shipping terms, and recurring production costs. |
| Quality assurance | Useful controls can include material verification, mechanical testing, dimensional inspection, visual examination, and non-destructive testing when required by the design or purchase specification. | Set acceptance criteria and inspection frequency in advance. Define required certificates, traceability, defect limits, corrective-action procedures, and approval of production samples. |
| Weight and freight | Cast iron has a density of approximately 7.1–7.3 g/cm³, depending on composition and structure. Its weight can therefore be a significant factor in transport and handling. | Calculate shipment weight and packaging dimensions from the actual casting and packing design. Confirm handling equipment, route constraints, and carrier limits for each shipment. |
| Packaging and transit protection | Castings can be damaged by impact, abrasion, moisture, or poor restraint during transit. Thin sections and machined surfaces may need particular protection. | Agree on secure blocking, separation between parts, protection for machined faces, moisture control where needed, and packaging suitable for the transport route and storage period. |
| Supplier and logistics planning | International sourcing adds lead-time, customs documentation, transport coordination, and communication requirements. Tooling development and sample approval can extend the initial schedule. | Confirm production capacity, sample and approval milestones, export documentation responsibilities, shipping terms, contingency lead time, and a clear process for handling changes. |