Equivalent Grades & Cross-Reference
Cross-reference designations across UNS, EN/DIN, ISO, SAE, and JIS standards. Comparable does not mean directly interchangeable. Always verify composition tolerance limits and mechanical requirements.
International standard designations are established by distinct standards bodies with differing testing standards (e.g. ASTM E8 vs ISO 6892-1). Even when chemical compositions overlap, allowable trace impurities (such as phosphorus, sulfur, or iron), grain size requirements, temper nomenclature, and minimum elongation criteria can differ.
Never authorize a structural alloy substitution without verifying the governing procurement specification, temper, ruling section size, and environmental compatibility.
Relationship Classification Governance
Identical chemical composition and mechanical requirements across different naming authorities.
Rule: Direct 1:1 dual specification permissible subject to certified mill test reports (MTR).Officially recognized counterpart in another national or international engineering standard (e.g. ASTM to EN).
Rule: Chemical limits or testing protocols may have subtle differences (e.g. tighter P/S ceilings or impact requirements). Engineering review required before substitution.Substantially identical chemistry and overlapping mechanical envelope, but slight variations in allowable trace elements or testing protocols exist across governing standards.
Rule: Direct commercial substitution is generally permissible subject to certified Mill Test Report (MTR) confirmation for critical applications.Similar base alloy chemistry and general functional properties, but noticeable divergence in allowable impurity ceilings, cold-work response, or minimum yield requirements.
Rule: Engineering substitution review required. Design calculations must verify temper, formability, and corrosion limits before specifying as a direct replacement.Similar base chemistry and functional performance envelope, but not officially harmonized by standards organizations.
Rule: Comparable does not mean equivalent. Heat treatment response and dimensional tolerances may diverge.Close metallurgical alternative when the primary grade is unavailable or obsolete.
Rule: Design parameters (weldability, hardenability, fatigue limit) must be re-evaluated for the specific application.Frequently evaluated side-by-side during trade-off studies or alloy selection.
Rule: Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost).Materials superficially mistaken for equivalents that exhibit critical metallurgical incompatibilities.
Rule: DO NOT SUBSTITUTE without full engineering re-qualification.| Source Alloy (UNS) | Relationship Type | Target Grade / Standard | Engineering Scope & Nuance | Actions |
|---|---|---|---|---|
| ASTM A48 Class 30 Gray Cast IronGray Cast Iron | Commonly Compared | ASTM A536 Grade 65-45-12 Ductile Cast IronConfidence: HIGH | 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. | |
| ASTM A48 Class 30 Gray Cast IronGray Cast Iron | Approximate Equivalent | EN-GJL-200 Gray Cast IronConfidence: MEDIUM | 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. | |
| ASTM A48 Class 30 Gray Cast IronGray Cast Iron | Commonly Compared | SAE 1018 Carbon SteelConfidence: HIGH | 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. | |
| ASTM A48 Class 35 Gray Cast IronGray Cast Iron | Commonly Compared | ASTM A48 Class 40 Gray Cast IronConfidence: HIGH | Class 35 provides slightly easier foundry gating and lower chilling in sections below 15 mm, while Class 40 is chosen when tensile loads reach 276 MPa. | |
| ASTM A48 Class 40 Gray Cast IronGray Cast Iron | Commonly Compared | ASTM A48 Class 30 Gray Cast IronConfidence: HIGH | Class 40 provides 33% higher minimum tensile strength (276 vs 207 MPa) and greater wear resistance, but Class 30 is easier to cast without chilled edges and offers higher thermal conductivity (48 vs 44 W/(m·K)). | |
| ASTM A48 Class 40 Gray Cast IronGray Cast Iron | Approximate Equivalent | EN-GJL-250 Gray Cast IronConfidence: MEDIUM | EN-GJL-250 (min 250 MPa tensile on 15–30 mm wall) provides similar structural duty to ASTM A48 Class 40 (min 276 MPa on 30.5 mm Test Bar B), but differing standard test specimen dimensions require careful engineering comparison. | |
| EN-GJL-300 Gray Cast IronGray Cast Iron | Commonly Compared | ASTM A48 Class 40 Gray Cast IronConfidence: HIGH | EN-GJL-300 provides higher tensile strength (300 MPa) than Class 40 (276 MPa), serving severe load cases in European engineering designs. |