Material designations
In one lineTranslate between naming systems freely — but substitute between specifications only with engineering approval.
Leads toSpecifying materials
Why this matters
Section titled “Why this matters”A heritage drawing calls up HE30, the supplier quotes EN AW-6082, the US partner says 6061, and the certificate carries a UNS number. They are related, not identical. Knowing how to read each system lets you follow a material across drawings, suppliers and countries; knowing where they differ stops a “nearest equivalent” quietly becoming a non-conformance.
How the numbering systems read
Section titled “How the numbering systems read”EN aluminium (EN 573). EN AW-6082: AW is aluminium wrought (AC is cast); the four digits follow the
international series (1xxx pure, 2xxx Cu, 5xxx Mg, 6xxx Mg–Si, 7xxx Zn). The temper follows the designation
(EN AW-6082-T6) and is defined by EN 515. Composition is EN 573-3; properties come from the product standard —
EN 485 sheet and plate, EN 755 extrusions, EN 754 drawn bar and tube.
EN steels (EN 10027). Two parallel systems. The name encodes composition: 34CrNiMo6 is about 0.34% carbon with
chromium, nickel and molybdenum, the last number giving the main alloying element’s content multiplied by a factor. The
number (1.6582) is a catalogue entry: 1.xxxx for steels.
EN stainless (EN 10088). X2CrNiMo17-12-2: X marks a high-alloy steel, then carbon ×100, the elements, and their
percentages — this one is 316L, number 1.4404. Part 2 covers sheet and plate, part 3 bar, rod and sections.
UNS. One letter and five digits across all metals: A aluminium, C copper, G carbon and alloy steels, K miscellaneous steels (D6AC is K24728), N nickel, R reactive and refractory metals including titanium, S stainless. Often the cleanest way to pin down exactly which grade someone means.
Aerospace specifications (AMS, BS L-series, AIR). These are specifications, not just names: they fix chemistry, product form, condition, testing and acceptance. Two L-series specs can be the same alloy and temper with different tolerances, and stock certified to one does not satisfy a drawing calling the other.
Cross-reference
Section titled “Cross-reference”Designation cross-reference
| Common name | BS EN / ISO | EN No. | Legacy BS | UNS | Aero / other | Note |
|---|---|---|---|---|---|---|
| Aluminium 1050A | EN AW-1050A / Al99.5 | 3.0255 | BS 1B | A91050 | ISO 209 Al 99.5 | Commercially pure. EN 485-2 sheet, EN 755-2 extrusion. |
| Aluminium 2014A | EN AW-2014A / AlCu4SiMg | 3.1255 | HE15 / H15 / HP15 / HT15 | A92014 | BS L168 (bar T6511) | High-strength forgings. Legacy UK 'L' spec still on heritage drawings. |
| Aluminium 2024 | EN AW-2024 / AlCu4Mg1 | 3.1355 | — | A92024 | AMS-QQ-A-250/4 | Fatigue-tolerant sheet. Usually clad (2024 Alclad). |
| Aluminium 2219 | EN AW-2219 / AlCu6Mn | 3.1341 | — | A92219 | AMS 4095 | The weldable cryogenic tankage alloy. |
| Aluminium 5083 | EN AW-5083 / AlMg4.5Mn0.7 | 3.3547 | BS N8 | A95083 | EN 485-2 | Marine and weldable plate. |
| Aluminium 6061 | EN AW-6061 / AlMg1SiCu | 3.3211 | HE20 | A96061 | AMS-QQ-A-200/8 | US general-purpose equivalent of 6082. |
| Aluminium 6082 | EN AW-6082 / AlSi1MgMn | 3.2315 | HE30 | A96082 | EN 755-2 / EN 485-2 | The UK workhorse. Highest strength of the 6000 series. |
| Aluminium 6063 | EN AW-6063 / AlMg0.7Si | 3.3206 | HE9 | A96063 | EN 755-2 | Architectural and smooth-finish extrusion. |
| Aluminium 7020 | EN AW-7020 / AlZn4.5Mg1 | 3.4335 | HE17 | A97020 | EN 755-2 | Weldable high-strength; age-hardens naturally after welding. |
| Aluminium 7075 | EN AW-7075 / AlZn5.5MgCu | 3.4365 | — | A97075 | AMS 4045 / 4147 (T73) | High-strength fittings. T73 for stress-corrosion resistance. |
| Aluminium 7050 | EN AW-7050 / AlZn6CuMgZr | 3.4144 | — | A97050 | AMS 4050 | Thick plate, better through-thickness properties. |
| Aluminium A356 / LM25 | EN AC-42100 / AlSi7Mg0.3 | — | BS 1490 LM25 | A03560 | EN 1706 | The general-purpose casting alloy. |
| Magnesium AZ31B | No EN 1753 designation — wrought | 3.5312 | BS 3370 MAG-S-1101 | M11311 | ASTM B90 (sheet) / B107 (extrusion) | EN 1753 covers ingots and castings only, so wrought AZ31 has no EN-MB/MC number. Procure to the ASTM product standards. |
| Magnesium AZ91 | EN-MC21120 / MgAl9Zn1(A) | 3.5912 | BS 2970 MAG7 | M11914 | EN 1753 / ISO 16220 | Most common die-casting magnesium. MB prefix = ingot, MC = casting. |
| Magnesium ZE41A | EN-MC35110 / MgZn4RE1Zr | — | BS 2970 MAG6 | M16410 | AMS 4439 | Pressure-tight castings, gearbox housings. |
| Magnesium WE43 | EN-MC95320 / MgY4RE3Zr | — | — | M18430 | AMS 4427 / ASTM B80 | Rare-earth, high temperature, self-extinguishing. |
| Magnesium Elektron 21 | EN-MC65120 / MgRE3Zn2Zr | — | — | M12310 | ASTM B80 (EV31A) | Modern castable RE alloy. EV31A is the ASTM designation. |
| CP Titanium Grade 2 | EN ISO Ti2 / Ti99.5 | 3.7035 | — | R50400 | AMS 4902 / EN 10204 | Formable, corrosion resistant, weldable. |
| Ti-6Al-4V (Grade 5) | TiAl6V4 | 3.7165 (see note) | — | R56400 | AMS 4911 sheet / 4928 bar | W.Nr usage varies between 3.7164/3.7165 by supplier and condition — UNS R56400 is the reliable discriminator. |
| Ti-6Al-4V ELI (Grade 23) | TiAl6V4 ELI | 3.7165 (see note) | — | R56401 | AMS 4907 / ISO 5832-2 | Fracture-critical and cryogenic grade. UNS R56401 distinguishes it from Grade 5. |
| Ti-3Al-2.5V (Grade 9) | TiAl3V2.5 | 3.7195 | — | R56320 | AMS 4945 (tube) | The standard lightweight tubing alloy. |
| Ti-5Al-2.5Sn (Grade 6) | TiAl5Sn2.5 | 3.7115 | — | R54520 | AMS 4926 | Weldable alpha alloy, cryogenic service. |
| Ti-6Al-2Sn-4Zr-2Mo | TiAl6Sn2Zr4Mo2 | 3.7145 | — | R54620 | AMS 4919 | High-temperature titanium, creep resistant. |
| Structural steel S355 | S355J2+N (EN 10025-2) | 1.0577 | BS 4360 50D | K12043 | EN 10025-2 | Rigs, frames, tooling. Never flight hardware. |
| 4130 chrome-moly | 25CrMo4 (EN 10083-3) | 1.7218 | BS 970 708A25 / CDS-110 | G41300 | AMS 6345 / 6360 | Weldable tube and sheet structure. |
| 4140 | 42CrMo4 (EN 10083-3) | 1.7225 | BS 970 708M40 (EN19) | G41400 | AMS 6382 | General high-strength shafts and tooling. |
| 4340 / EN24 | 34CrNiMo6 (EN 10083-3) | 1.6582 | BS 970 817M40 (EN24) | G43400 | AMS 6415 | Shafts, pins, gears. Bake after plating. |
| 15CDV6 | 15CrMoV6 | 1.7734 | — | K11562 | AIR 9160C | Weldable case steel — no post-weld heat treatment needed. |
| D6AC | — | — | — | K24728 | AMS 6431 (VAR) | Classic solid motor case steel. No direct EN equivalent. |
| 300M | — | — | S155 (legacy) | K44220 | AMS 6417 | Ultra-high strength; extremely hydrogen sensitive. |
| Maraging 18Ni-250 | X2NiCoMo18-8-5 | 1.6359 | — | K92890 | AMS 6512 / 6520 | Ages with almost no distortion; welds annealed. |
| Tool steel H13 | X40CrMoV5-1 (EN ISO 4957) | 1.2344 | BS 4659 BH13 | T20813 | EN ISO 4957 | Hot-work dies and moulds. |
| Tool steel D2 | X153CrMoV12 (EN ISO 4957) | 1.2379 | BS 4659 BD2 | T30402 | EN ISO 4957 | Cold-work blanking tools. |
| Tool steel O1 | 100MnCrW4 (EN ISO 4957) | 1.2510 | BS 4659 BO1 | T31501 | EN ISO 4957 | Oil-hardening gauges and jigs. |
| Grey cast iron | EN-GJL-250 (EN 1561) | EN-JL1040 | BS 1452 Grade 250 | F12401 | EN 1561 | Machine bases, damping-critical tooling. |
| Stainless 304L | X2CrNi18-9 (EN 10088-3) | 1.4307 | BS 970 304S11 | S30403 | EN 10088-2 sheet | General austenitic, ground equipment. |
| Stainless 316L | X2CrNiMo17-12-2 (EN 10088-3) | 1.4404 | BS 970 316S11 | S31603 | EN 10088-2 | Mo-bearing, wet systems and marine. |
| Stainless 321 | X6CrNiTi18-10 (EN 10088-3) | 1.4541 | BS 970 321S31 | S32100 | AMS 5510 | Ti-stabilised for welded hot ducting. |
| Stainless 347 | X6CrNiNb18-10 (EN 10088-3) | 1.4550 | BS 970 347S31 | S34700 | AMS 5512 | Nb-stabilised alternative to 321. |
| Stainless 410 | X12Cr13 (EN 10088-3) | 1.4006 | BS 970 410S21 | S41000 | EN 10088-3 | Hardenable martensitic. |
| Stainless 440C | X105CrMo17 (EN 10088-3) | 1.4125 | BS 970 440C | S44004 | AMS 5630 | Bearings and wear pins, ~58 HRC. |
| 17-4PH | X5CrNiCuNb16-4 (EN 10088-3) | 1.4542 | BS 970 (no direct) | S17400 | AMS 5643 | ALWAYS state the H-condition (H900/H1025/H1075). |
| 15-5PH | X5CrNiCuNb15-5 | 1.4545 | — | S15500 | AMS 5659 | Cleaner, tougher 17-4 variant for forgings. |
| 13-8Mo PH | X3CrNiMoAl13-8-2 | 1.4534 | — | S13800 | AMS 5629 | Highest-strength PH stainless. |
| Duplex 2205 | X2CrNiMoN22-5-3 (EN 10088-3) | 1.4462 | — | S32205 | EN 10088-3 | Chloride and stress-corrosion resistant. |
| A286 | X5NiCrTi26-15 (EN 10269) | 1.4980 | — | S66286 | AMS 5731 / 5737 | Budget superalloy fastener stock to ~650 °C. |
| 21-6-9 (Nitronic 40) | X8CrMnNiN18-8 | 1.3815 | — | S21900 | AMS 5561 (tube) | High-pressure pneumatic/hydraulic tubing. |
| Inconel 718 | NiCr19Fe19Nb5Mo3 (EN 10302) | 2.4668 | HR 8 / HR 401 | N07718 | AMS 5662 / 5663 | The PH superalloy workhorse. |
| Inconel 625 | NiCr22Mo9Nb | 2.4856 | HR 6 | N06625 | AMS 5599 / 5666 | Weldable, oxidation resistant, serves hotter than 718. |
| Inconel 600 | NiCr15Fe | 2.4816 | HR 204 | N06600 | AMS 5540 | General high-temperature. |
| Inconel X-750 | NiCr15Fe7TiAl | 2.4669 | HR 505 | N07750 | AMS 5598 / 5667 | Hot springs and fasteners. |
| Waspaloy | NiCr19Co14Mo4Ti3Al | 2.4654 | HR 10 | N07001 | AMS 5704 / 5708 | Where 718 runs out of temperature. |
| Hastelloy X | NiCr22Fe18Mo | 2.4665 | HR 6 (rel.) | N06002 | AMS 5536 | Formable hot sheet-metal structure. |
| Haynes 230 | NiCr22W14Mo | 2.4733 | — | N06230 | AMS 5878 | Outstanding oxidation resistance to ~1150 °C. |
| Haynes 188 | CoCr22Ni22W14 | 2.4683 | — | R30188 | AMS 5772 | Cobalt-base hot-section alloy. |
| Nimonic 90 | NiCr20Co18Ti | 2.4632 | HR 2 / HR 502 | N07090 | BS HR 2 | Turbine blades and hot bolting. |
| Monel 400 | NiCu30Fe | 2.4360 | BS 3072 NA13 | N04400 | EN 10204 | Seawater and oxygen service. |
| Monel K-500 | NiCu30Al | 2.4375 | BS 3072 NA18 | N05500 | AMS 4676 | Age-hardened, good galling resistance. |
| Invar 36 | FeNi36 | 1.3912 | — | K93600 | ASTM F1684 | Near-zero expansion composite tooling. |
| Kovar | FeNi29Co17 | 1.3981 | — | K94610 | ASTM F15 | Glass-to-metal and ceramic seals. |
| Copper C101 (ETP) | Cu-ETP (EN 13601) | CW004A | BS 2870 C101 | C11000 | EN 13601 | Conductors, heat sinks, chill blocks. |
| Brass CZ121 | CuZn39Pb3 (EN 12164) | CW614N | BS 2874 CZ121 | C38500 | EN 12164 | The free-machining brass. |
| Beryllium copper | CuBe2 (EN 12163) | CW101C | BS 2873 CB101 | C17200 | AMS 4533 | Non-sparking tools, springs, bushes. |
| Phosphor bronze | CuSn6 (EN 12163) | CW452K | BS 2870 PB103 | C51900 | EN 12163 | Springs and electrical contacts. |
| Bearing bronze | CuSn7Zn4Pb7 (EN 1982) | CC493K | BS 1400 LG2 | C93200 | EN 1982 | Bushes and plain bearings. |
| CuCrZr | CuCr1Zr (EN 12163) | CW106C | — | C18150 | EN 12163 | Conductive and heat resistant; resistance welding electrodes. |
| C-103 Niobium | Nb-10Hf-1Ti | — | — | R04295 | AMS 7857 | Radiation-cooled nozzle extensions. Needs silicide coating. |
| TZM Molybdenum | Mo-Ti-Zr | — | — | R03640 | ASTM B387 | Creep-resistant hot structure and tooling. |
| Tungsten | W (EN ISO 4499 rel.) | — | — | R07005 | ASTM B760 | Throat inserts, ballast, erosion resistance. |
| Ta-10W | Ta-10W | — | — | R05255 | ASTM B708 | Ductile refractory for small hot components. |
Nearest equivalents, not interchangeable grades. Composition limits, melt practice, testing and acceptance differ between systems.
References
Section titled “References”- BS EN 573 (aluminium designations and composition), BS EN 515 (aluminium tempers).
- BS EN 10027-1 and -2 (steel names and numbers), BS EN 10088 (stainless steels).
- SAE/ASTM, Metals and Alloys in the Unified Numbering System (UNS).