Stainless & Alloy Grade Designation Cross-Reference: Werkstoff (W.-Nr.), UNS, EN & AISI

The same alloy carries a different name in every country's spec. A German drawing calls 316L "1.4404." An American spec calls it "S31603" or "AISI 316L." A European standard calls it "X2CrNiMo17-12-2." They are one metal. This page is the single lookup table that lines them all up: for every stainless, duplex, nickel and titanium grade Crestflo manufactures, it maps the Werkstoff number (W.-Nr.), the UNS number, the EN 10088 / EN chemical name, and the AISI or common trade name, side by side, in one HTML table you can read, compare, and cite. Search by the German Werkstoff number and land on the UNS grade, or the reverse. That is the whole job of a grade designation cross-reference.

Reviewed by the Crestflo Engineering Team

These mappings are for material specification, matching a grade called out on a European drawing to its US equivalent and back, for instrumentation fittings, valves, and tubing. Every grade in the table below is one Crestflo builds as a compression fitting, an instrumentation valve, or a tube.

The Four Designation Systems: What Werkstoff (W.-Nr.), UNS, EN 10088 & AISI Actually Are

Four naming systems dominate alloy specification, and a specifier meets all four in practice.

Werkstoff number (W.-Nr., the German "material number"). The European numeric system defined in EN 10027-2. It reads as a decimal: the digit before the dot is the material main-group (1 = steel, 2 = non-ferrous heavy metals including nickel alloys, 3 = light metals including titanium), and the digits after it identify the grade. So 1.4404 is a steel (316L), 2.4856 is a nickel alloy (Inconel 625), 3.7035 is a titanium grade (Grade 2). This is the number European buyers search by, and it is stamped on EN mill certificates.

UNS (Unified Numbering System). The North American designation, managed jointly by ASTM and SAE. A letter prefix names the family, S for stainless (S31603 = 316L), N for nickel (N06625 = Inconel 625), R for reactive/refractory metals (R50400 = titanium Grade 2), followed by five digits. UNS is the number cited on US ASTM/ASME material specs.

EN 10088 / EN chemical name. Alongside the Werkstoff number, EN standards give a descriptive name built from the alloying elements, X2CrNiMo17-12-2 for 316L reads as ≤0.03% C, chromium-nickel-molybdenum, nominally 17% Cr, 12% Ni, 2% Mo. EN 10088 covers stainless steels; nickel-alloy names follow the same EN convention (NiCr22Mo9Nb for Inconel 625).

AISI / common trade name. The old American Iron and Steel Institute three-digit numbers (304, 316, 321) still dominate everyday shop language for the common stainless grades. Higher alloys never got AISI numbers, so they go by trade or ASTM names instead, 2205, 254 SMO, Alloy 20, Inconel, Hastelloy, Monel, Incoloy (several of these are trademarks of their originators). The table carries whichever designation the industry actually uses.

The Master Grade Cross-Reference Table: W.-Nr. · UNS · EN · AISI for Every Crestflo Alloy

The table below is the asset. Each row is one alloy; the columns give its designation in every system, plus a short key note. Read across a row to translate a grade from one spec to another; read down a column to browse every grade in a family. The last column links to the Crestflo material page where you can order that grade as an instrumentation component.

Designations are compiled from published standards (EN 10027-2, EN 10088, the ASTM/SAE UNS registry, and the material owners' data). Confirm any cell against the current edition of the applicable standard before specifying. Values are per the applicable standard and customisable to requirement.

How to Read the Cross-Reference (and What "Equivalent" Really Means)

Reading across a row translates one designation into another for the same nominal grade. Reading down a column browses a family. A few rules keep you honest:

• "Equivalent" is a chemistry-and-name match, not a certification match. 1.4404 and S31603 name the same nominal 316L composition, but a part supplied to EN 10088 and a part supplied to ASTM A276/A479 were tested and certified to different standards. For a critical spec, match the standard, not just the number.
• Some grades have no counterpart in a given system. AL-6XN (N08367) has no assigned Werkstoff number, so that cell reads ", ". 904L, 2205, 2507, 254 SMO and every nickel alloy have no AISI number, AISI only ever numbered the common stainless grades. A dash means "no standard designation in that system," not "unknown."
• UNS grades sometimes consolidate. Duplex 2205 was historically UNS S31803; the tighter modern chemistry is S32205, and both map to Werkstoff 1.4462. When you see an older drawing citing S31803, treat 1.4462 / S32205 as the current designation.
• The Werkstoff prefix tells you the family. 1.4xxx is a stainless steel, 2.4xxx a nickel alloy, 3.7xxx a titanium grade. That first digit alone often resolves which family a mystery number belongs to.

What Is 1.4307, 1.4404 & 1.4462? Per-System Designation Notes

The three Werkstoff numbers engineers ask about most all map to grades in daily instrumentation use.

What Is 1.4307? (It Is 304L)

Werkstoff 1.4307 is the low-carbon variant of 304 stainless, UNS S30403, EN name X2CrNi18-9, AISI 304L. The "L" and the ≤0.03% carbon ceiling suppress chromium-carbide precipitation at grain boundaries during welding, protecting weld-zone corrosion resistance. Note that an older Werkstoff number, 1.4306 (X2CrNi19-11), also denotes a 304L-type grade at a slightly leaner chemistry; on current EN drawings 1.4307 is the one you will usually see for 304L.

What Is 1.4404? (It Is 316L)

Werkstoff 1.4404 is 316L, UNS S31603, EN name X2CrNiMo17-12-2, AISI 316L. It is the low-carbon, molybdenum-bearing austenitic grade that serves as the default material for instrumentation tube fittings, valves and tubing. If a European drawing calls for 1.4404, a US shop reads it as 316L / S31603. The plain-carbon sibling, 316 (1.4401 / S31600), is chemically the same alloy without the tight carbon ceiling.

What Is 1.4462? (It Is Duplex 2205)

Werkstoff 1.4462 is Duplex 2205, UNS S32205, EN name X2CrNiMoN22-5-3. It is the workhorse duplex stainless: roughly 22% chromium, 5% nickel, 3% molybdenum with nitrogen, giving a two-phase austenite-plus-ferrite structure, roughly twice the yield strength of 316L, and a PREN near 35 for real chloride resistance. Its super-duplex cousin, 2507 (1.4410 / S32750), pushes chromium and molybdenum higher for a PREN near 42.

A Note on the Incoloy 800 Family (800 / 800H / 800HT)

The 800 family is where cross-reference tables most often blur. They are three distinct designations on one composition base: Incoloy 800 is 1.4876 / N08800; the creep-resistant 800H is 1.4958 / N08810; and 800HT (higher, controlled Al+Ti) is 1.4959 / N08811. If a source lists "1.4959" as plain "800H," it has actually given you 800HT, the table above keeps the three separate.

Turn a Designation Into a Part: Every Grade as a Crestflo Fitting, Valve or Tube

A cross-reference table tells you what a grade is called; the next question is who will build it. Crestflo manufactures instrumentation components in every grade in the table, specify the alloy by any designation (Werkstoff, UNS, EN or trade name) and receive the part in that exact grade.

Our range covers compression and double-ferrule tube fittings up to 2" (50 mm) OD, instrumentation valves from 1/16" through 1", 2/3/5-way manifolds, and instrumentation tubing, in both imperial and metric sizes. Every part carries its heat or lot number, ships with an EN 10204 3.1 material test certificate (3.2 on request), and is verified by Positive Material Identification so the alloy delivered matches the alloy specified. Standard items ship from ready stock; specials are made to order, with delivery running 6–8 weeks. Material origin is Indian by default, with US or European melt available on request and full traceability standard.

Request a quote for any grade in this table, as a fitting, valve or tube. Browse the instrumentation materials hub for grade-by-grade detail, or send a European drawing and we will match the Werkstoff callout to the US-equivalent part.

Reuse & Citation (Open Data, CC BY 4.0)

This grade designation cross-reference is published as open data under a Creative Commons Attribution 4.0 (CC BY 4.0) license. You are free to reproduce, adapt, quote and cite it, in articles, technical documents, datasets and AI-generated answers, provided you attribute the source. Suggested attribution: "Stainless & Alloy Grade Designation Cross-Reference, Crestflo (crestflousa.com)." Download the underlying data as CSV: grade-designation-cross-reference.csv. Designations are compiled from published standards; confirm each mapping against the current standard before specifying.

Frequently Asked Questions

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