ASTM / ASME
American specifications for product forms — for example A312 pipe, A240 plate or A182 forgings. The “SA” prefix is the ASME boiler-code version of the same ASTM standard.
Material Grades
Material Grades & Equivalents
Every material family we supply, with the grades buyers ask for most — cross-referenced to UNS numbers, EN / Werkstoff numbers and the ASTM / ASME specifications we supply against.
Before You Start
Reading the Tables
A short guide to the designations used on this page.
Anatomy of a designationHover, tap or wait — each part lights up its explanation below
UNS Number
Unified Numbering System: a letter plus five digits, such as S31603. It identifies the exact chemistry range of an alloy across standards.
EN / W.Nr.
European designations. The Werkstoff number, such as 1.4404, is a material number used in EN standards and across Europe.
Letter Suffixes
L = low carbon, H = higher carbon, Ti or Nb = stabilised, N = nitrogen added, Mo = molybdenum. A small letter changes welding and heat behaviour.
Corrosion Resistance
Pitting Resistance at a Glance
PREN — the Pitting Resistance Equivalent Number — ranks stainless grades by how well they resist pitting in chloride environments.
It is calculated as %Cr + 3.3 × %Mo + 16 × %N. A higher number means better resistance. Use it to compare grades, not as a guarantee of performance in a specific service.
Typical values only; the actual PREN depends on the chemistry of the heat supplied.
Typical PREN
PREN 40 — the figure usually quoted for seawater service
SS 304≈ 19
SS 316L≈ 24
SS 317L≈ 29
SS 904L≈ 35
Duplex 2205≈ 35
Super Duplex 2507≈ 42
Grade Tables
Find Your Grade
Search by grade, UNS number, EN number or use, or jump to a family.
01 Austenitic Stainless Steel
13 gradesThe 300-series and super-austenitic grades — non-magnetic, formable and widely welded.
| Grade | UNS | EN / W.Nr. | JIS | Character & Typical Use |
|---|---|---|---|---|
| SS 304 | S30400 | 1.4301 | SUS304 | The general-purpose 18/8 grade — tanks, dairy, architecture, process lines. |
| SS 304L | S30403 | 1.4307 | SUS304L | Low-carbon 304 for welded fabrication without post-weld heat treatment. |
| SS 304H | S30409 | 1.4948 | — | Higher carbon for strength at elevated temperature. |
| SS 309S | S30908 | 1.4833 | SUS309S | Oxidation resistant at high temperature — furnace and heat-treatment parts. |
| SS 310S | S31008 | 1.4845 | SUS310S | Heat resistant, with 25% chromium — furnaces, kilns and burners. |
| SS 316 | S31600 | 1.4401 | SUS316 | Molybdenum-bearing; better chloride and pitting resistance than 304. |
| SS 316L | S31603 | 1.4404 | SUS316L | Low-carbon 316 — marine, chemical, pharma and welded construction. |
| SS 316Ti | S31635 | 1.4571 | SUS316Ti | Titanium-stabilised 316 for welded parts in hot service. |
| SS 317L | S31703 | 1.4438 | SUS317L | Higher molybdenum than 316L for more aggressive chemical media. |
| SS 321 | S32100 | 1.4541 | SUS321 | Titanium-stabilised — resists sensitisation in the 425–850 °C range. |
| SS 347 | S34700 | 1.4550 | SUS347 | Niobium-stabilised — high-temperature and refinery service. |
| SS 904L | N08904 | 1.4539 | SUS890L | Super-austenitic with copper — sulphuric and phosphoric acid service. |
| 254 SMO | S31254 | 1.4547 | — | 6% molybdenum super-austenitic — seawater and bleach plants. |
02 Ferritic, Martensitic & PH
6 gradesMagnetic grades for automotive, tooling and high-strength applications.
| Grade | UNS | EN / W.Nr. | JIS | Character & Typical Use |
|---|---|---|---|---|
| SS 409 | S40900 | 1.4512 | SUH409L | Low-cost ferritic — automotive exhaust systems. |
| SS 410 | S41000 | 1.4006 | SUS410 | Hardenable martensitic — valve parts, pump shafts, cutlery. |
| SS 420 | S42000 | 1.4021 | SUS420J1 | Higher carbon martensitic — cutting tools, surgical instruments. |
| SS 430 | S43000 | 1.4016 | SUS430 | General-purpose ferritic — appliances and architectural trim. |
| SS 431 | S43100 | 1.4057 | SUS431 | Martensitic with nickel — shafts and fasteners needing toughness. |
| 17-4 PH | S17400 | 1.4542 | SUS630 | Precipitation hardening — high strength with good corrosion resistance. |
03 Duplex & Super Duplex
5 gradesMixed austenite-ferrite structure: roughly twice the strength of 304 with good chloride resistance.
| Grade | UNS | EN / W.Nr. | JIS | Character & Typical Use |
|---|---|---|---|---|
| Lean Duplex 2101 | S32101 | 1.4162 | — | Economical duplex with high strength — storage tanks and structures. |
| Duplex 2304 | S32304 | 1.4362 | — | Lean duplex with good stress-corrosion resistance. |
| Duplex 2205 | S31803 / S32205 | 1.4462 | SUS329J3L | The workhorse duplex — oil & gas, chemical and desalination. |
| Super Duplex 2507 | S32750 | 1.4410 | — | PREN above 40 — seawater, offshore and aggressive chlorides. |
| Zeron 100 | S32760 | 1.4501 | — | Super duplex with tungsten — severe chloride service. |
04 Nickel Alloys & Titanium
13 gradesHigh-performance alloys for severe corrosion, heat and strength demands.
| Alloy | UNS | W.Nr. | Character & Typical Use |
|---|---|---|---|
| Nickel 200 | N02200 | 2.4066 | Commercially pure nickel — caustic soda and food processing. |
| Monel 400 | N04400 | 2.4360 | Nickel-copper — seawater, hydrofluoric acid and marine. |
| Inconel 600 | N06600 | 2.4816 | Nickel-chromium — heat treatment and chemical processing. |
| Inconel 601 | N06601 | 2.4851 | Excellent oxidation resistance — furnace equipment. |
| Inconel 625 | N06625 | 2.4856 | High strength and corrosion resistance — marine and aerospace. |
| Inconel 718 | N07718 | 2.4668 | Precipitation-hardened — high-strength, high-temperature parts. |
| Incoloy 800 / 800H | N08800 / N08810 | 1.4876 / 1.4958 | Heat-resistant iron-nickel — petrochemical and heat exchangers. |
| Incoloy 825 | N08825 | 2.4858 | Resists sulphuric and phosphoric acids — chemical and pickling. |
| Hastelloy C-276 | N10276 | 2.4819 | Outstanding resistance to oxidising and reducing acids. |
| Hastelloy C-22 | N06022 | 2.4602 | Versatile alloy for mixed acids and chlorides. |
| Titanium Grade 1 | R50250 | 3.7025 | Softest commercially pure grade — formability and corrosion resistance. |
| Titanium Grade 2 | R50400 | 3.7035 | The standard commercially pure grade — heat exchangers and marine. |
| Titanium Grade 5 | R56400 | 3.7165 | Ti-6Al-4V — high-strength aerospace and medical alloy. |
05 Alloy Steels (Cr-Mo)
5 gradesChromium-molybdenum steels for high-temperature piping, with the matching product specifications.
| Grade | Nominal Composition | Pipe & Tube | Forging | Fitting | Plate | UNS (pipe) |
|---|---|---|---|---|---|---|
| P5 | 5Cr–½Mo | A335 P5 | A182 F5 | A234 WP5 | A387 Gr 5 | K41545 |
| P9 | 9Cr–1Mo | A335 P9 | A182 F9 | A234 WP9 | A387 Gr 9 | S50400 |
| P11 | 1¼Cr–½Mo | A335 P11 | A182 F11 | A234 WP11 | A387 Gr 11 | K11597 |
| P22 | 2¼Cr–1Mo | A335 P22 | A182 F22 | A234 WP22 | A387 Gr 22 | K21590 |
| P91 | 9Cr–1Mo–V | A335 P91 | A182 F91 | A234 WP91 | A387 Gr 91 | K91560 |
06 Carbon Steel
9 gradesCarbon steel is specified by ASTM or API specification rather than by a single grade name.
| Specification | Product | Character & Typical Use |
|---|---|---|
| ~ASTM A106 Gr B / C | Seamless pipe | High-temperature service. Gr C has higher strength. |
| ~ASTM A53 Gr B | Pipe (seamless or welded) | General-purpose pipe for steam, water, gas and air. |
| ~API 5L Gr B / X42–X70 | Line pipe | Oil, gas and water pipelines. |
| ~ASTM A333 Gr 6 | Pipe | Low-temperature service, down to about −45 °C. |
| ~ASTM A234 WPB | Buttweld fittings | Matches A106 Gr B pipe. |
| ~ASTM A105 | Forged flanges & fittings | Ambient and elevated-temperature service. |
| ~ASTM A350 LF2 | Forgings | Impact tested for low-temperature service, to about −46 °C. |
| ~ASTM A516 Gr 60 / 70 | Pressure-vessel plate | Moderate and lower-temperature pressure vessels. |
| ~ASTM A36 · IS 2062 E250 | Plate & sections | General structural steel. |
No grade matches that search. Try a different term, or ask us.
Equivalents are the nearest standard match and are not always identical in every requirement. Confirm the exact specification on your purchase order. “—” means we have not listed a designation.
Grade Selection
Which Grade for Which Service?
A starting point only — the right grade also depends on temperature, concentration and design code.
- Service
General water, food, dairy, architecture
Typical choiceSS 304 / 304LWhyGood all-round corrosion resistance at the lowest stainless cost.
- Service
Chlorides, coastal and chemical plants
Typical choiceSS 316 / 316LWhyMolybdenum resists pitting where 304 would fail.
- Service
Heavily welded fabrication
Typical choiceL grades — 304L / 316LWhyLow carbon limits sensitisation in the weld zone.
- Service
Hot service, 425–850 °C
Typical choiceSS 321 / 347304HWhyStabilised or higher-carbon grades hold up in the sensitising range.
- Service
Very high temperature, oxidising
Typical choiceSS 309S / 310SWhyHigh chromium and nickel resist scaling.
- Service
High chloride, stress-corrosion risk
Typical choiceDuplex 2205WhyHigh strength and good resistance to chloride stress-corrosion cracking.
- Service
Seawater and offshore
Typical choiceSuper duplex 25076MoCu-NiWhyVery high pitting resistance (PREN above 40).
- Service
Sulphuric and phosphoric acid
Typical choice904LAlloy 825Alloy 20WhyCopper and nickel additions resist reducing acids.
- Service
Severe mixed acids
Typical choiceHastelloy C-276 / C-22WhyResists both oxidising and reducing media.
- Service
High-temperature steam piping
Typical choiceP11P22P91WhyChromium-molybdenum steels keep strength at temperature.
- Service
Light weight, high strength
Typical choiceTitanium Gr 2 / Gr 5WhyExcellent corrosion resistance at low density.
Not sure? Tell us the medium, temperature and pressure and we will suggest a suitable grade. Ask our team.