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 |
|---|---|---|---|---|
| Polyester Polyurethane (AU)Polyurethane Elastomers | Close Equivalent | Polyether Polyurethane (EU)Confidence: HIGH | Critical formulation trade-off: AU provides superior sliding abrasion resistance and petroleum oil resistance; EU provides superior water/humidity hydrolysis resistance and better low-temperature flexibility. | |
| Polyester Polyurethane (AU)Polyurethane Elastomers | Commonly Compared | Nitrile Butadiene Rubber (NBR)Confidence: HIGH | AU delivers vastly superior tensile strength, tear strength, and extrusion resistance for high-pressure hydraulic rod seals; NBR provides lower cost and superior water/glycol stability. | |
| Polyether Polyurethane (EU)Polyurethane Elastomers | Close Equivalent | Polyester Polyurethane (AU)Confidence: HIGH | Deciding between polyurethanes: EU should always be chosen when continuous water immersion, high humidity, subsea, or slurry contact is present due to hydrolytic stability; AU is chosen for maximum dry sliding abrasion and fuel/oil resistance. | |
| Polyether Polyurethane (EU)Polyurethane Elastomers | Commonly Compared | Ethylene Propylene Diene Rubber (EPDM)Confidence: HIGH | Both materials resist water and weathering; EU delivers far higher tensile strength, cut resistance, and dynamic slurry wear endurance; EPDM operates at higher steam temperatures (+150°C vs +80°C). |