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 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. | |
| EN-GJL-250 Gray Cast IronGray Cast Iron | Approximate Equivalent | ASTM A48 Class 35 Gray Cast IronConfidence: MEDIUM | EN-GJL-250 (min 250 MPa tensile on 15–30 mm wall) closely mirrors ASTM A48 Class 35 (min 241 MPa on 30.5 mm Test Bar B) in microstructure, hardness, and machine tool engineering service. | |
| EN-GJL-250 Gray Cast IronGray Cast Iron | Commonly Compared | EN-GJS-500-7 Ductile Cast IronConfidence: HIGH | Comparison of flake vs spheroidal graphite: EN-GJL-250 provides higher vibration damping, thermal conductivity, and machinability, while EN-GJS-500-7 offers double the tensile strength (500 vs 250 MPa) and true elongation (7%). |