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
Show All TypesIdentical 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 |
|---|---|---|---|---|
| Nitrile Butadiene Rubber (NBR)Oil & Fuel Resistant Elastomers | Commonly Compared | Ethylene Propylene Diene Rubber (EPDM)Confidence: HIGH | Classic polar vs non-polar trade-off: NBR resists petroleum oils and fuels but is degraded by polar solvents and ozone; EPDM resists ozone, hot water, and steam but is destroyed by petroleum hydrocarbons. | |
| Nitrile Butadiene Rubber (NBR)Oil & Fuel Resistant Elastomers | Commonly Compared | Fluoroelastomer (FKM)Confidence: HIGH | FKM provides higher continuous temperature resistance (+200°C) and aggressive synthetic fuel resistance at significantly higher material cost than NBR. | |
| Hydrogenated Nitrile Rubber (HNBR)Oil & Fuel Resistant Elastomers | Commonly Compared | Fluoroelastomer (FKM)Confidence: HIGH | HNBR provides superior mechanical toughness, tear resistance, and dynamic abrasion over FKM; FKM provides higher continuous heat resistance (+200°C) and broader chemical resistance. | |
| Silicone Rubber (VMQ)High-Temperature & Specialty Elastomers | Commonly Compared | Fluoroelastomer (FKM)Confidence: HIGH | VMQ offers unmatched low-temperature flexibility (-60°C) and lower material cost; FKM offers vastly superior fuel, chemical, and solvent resistance and higher tensile/tear strength. | |
| Silicone Rubber (VMQ)High-Temperature & Specialty Elastomers | Commonly Compared | Ethylene Propylene Diene Rubber (EPDM)Confidence: HIGH | Both resist ozone and weathering; VMQ extends continuous temperature range to +200°C (-60°C to +200°C), whereas EPDM provides higher mechanical tear strength and lower cost up to 125°C. | |
| Fluoroelastomer (FKM)High-Temperature & Specialty Elastomers | Commonly Compared | Nitrile Butadiene Rubber (NBR)Confidence: HIGH | FKM provides superior high-temperature capability (+200°C vs +100°C) and broader fuel resistance; NBR offers lower cost and better low-temperature flexibility (-30°C vs -15°C). | |
| Fluoroelastomer (FKM)High-Temperature & Specialty Elastomers | Commonly Compared | Hydrogenated Nitrile Rubber (HNBR)Confidence: HIGH | FKM resists higher temperatures and aggressive synthetic engine oils; HNBR provides superior mechanical tensile strength, dynamic cut-growth resistance, and better low-temperature behavior. | |
| Fluoroelastomer (FKM)High-Temperature & Specialty Elastomers | Commonly Compared | Silicone Rubber (VMQ)Confidence: HIGH | VMQ offers superior low-temperature performance down to -60°C; FKM provides unmatched resistance to fuels, petroleum oils, and chemical solvents where VMQ swells and dissolves. |