Steel Grade Identifier

Look up a steel grade designation to find its properties, equivalent grades in other standards, and common uses.

Reference

How to Use

  1. 1
    Select the Designation System and Enter the Grade

    Choose the designation system (UNS, AISI/SAE, EN/DIN, JIS, BS, or GB) and type in the grade designation; the tool normalizes synonyms and common alternate designations.

  2. 2
    Review Cross-Reference Results

    The nearest equivalent grades in all major standards systems are displayed with a similarity rating, distinguishing between exact equivalents and near-equivalents with minor compositional differences.

  3. 3
    Download the Composition Summary

    View the full chemical composition ranges, key mechanical properties in standard conditions, and applicable ASTM/ISO product standards for the identified grade.

About

Steel grade identification is a daily challenge in materials management, procurement, and inspection because the same alloy is designated differently across national and international standards systems. A part specified as AISI 4340, purchased as 36CrNiMo4 (EN), certified to DIN 1.6511, and tested against JIS SNCM439 may be the same alloy — or it may have subtly different composition limits that matter for a critical application.

The AlloyFYI Steel Grade Identifier maintains a comprehensive cross-reference database built from ASTM, SAE, EN, JIS, BS, DIN, GB, and GOST standards, cross-linked by UNS designation as the neutral reference key. The tool supports both designation-to-composition lookup and composition-to-grade matching, enabling positive material identification (PMI) from spectrometric analysis results. For procurement and quality engineers working in globally distributed supply chains, accurate grade identification prevents costly material non-conformances and supports the material traceability requirements of ASME, ISO 9001, and AS9100 quality management systems.

FAQ

What is the UNS numbering system and why is it important?
The Unified Numbering System (UNS), jointly maintained by SAE International and ASTM International, provides a unique alphanumeric designation for every commercially significant metal alloy. UNS numbers begin with a letter indicating the alloy family (S for stainless steels, A for aluminum, C for copper, G for carbon and alloy steels) followed by five digits encoding the specific composition. UNS provides an unambiguous single identifier that resolves the ambiguity among national designation systems, making it the preferred cross-reference key in international purchasing specifications and material test reports.
How do AISI 304 and EN 1.4301 relate to each other?
AISI 304 is the American Iron and Steel Institute designation for an 18Cr-8Ni austenitic stainless steel, the most widely used grade worldwide. EN 1.4301 is the equivalent designation in the European EN 10088 standard (the numerical material designation system used across the EU). Both specify the same nominal composition (≤18% Cr, 8–10.5% Ni, ≤0.07% C) but with slightly different tolerance ranges for individual elements. The UNS designation S30400 is the unambiguous cross-reference that encompasses both designations. The Japanese equivalent is SUS304 per JIS G4303.
What does the 'L' suffix mean in stainless steel grades like 304L and 316L?
The 'L' suffix denotes a low-carbon variant with maximum carbon content of 0.03% versus 0.07–0.08% for the standard grade. Low carbon content prevents sensitization (chromium carbide precipitation at grain boundaries during welding or elevated-temperature service), maintaining corrosion resistance in the as-welded condition without requiring post-weld annealing. The 'L' grades have slightly lower minimum yield and tensile strengths than the standard grades and are preferred for welded construction in corrosive service. The 'H' suffix (e.g., 316H) indicates a high-carbon variant for elevated-temperature strength applications.
How do I identify an unknown steel by its chemistry from a spectrometric analysis?
Enter the measured elemental weight percentages into the steel grade identifier's composition search feature. The tool compares the input against the full compositional specification range for each grade in the database and returns all grades where the measured composition falls within the specified min-max ranges. For the result to be definitive, all specified elements must fall within range; a result showing 'composition within range but outside key element' identifies the nearest grade while flagging the discrepancy. Always verify the result against physical and mechanical property evidence (hardness, microstructure) for full positive material identification (PMI) compliance.
What is the difference between stainless steel grade 2205 and super-duplex grade 2507?
2205 (UNS S32205/S31803) is the workhorse duplex stainless steel with approximately 22% Cr, 5% Ni, 3% Mo, and 0.17% N, giving a PREN of approximately 35 and a minimum yield strength of 450 MPa. Super-duplex 2507 (UNS S32750) contains approximately 25% Cr, 7% Ni, 4% Mo, and 0.28% N, raising PREN to approximately 43 and yield strength to 550 MPa minimum. The higher alloy content of 2507 provides substantially better resistance to pitting and crevice corrosion in seawater and aggressive chemical environments, at roughly double the material cost. 2205 is appropriate for mildly aggressive seawater service; 2507 is specified for subsea pipelines, desalination plants, and high-chloride chemical processing.
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