Thirty-three grades across five metallurgical families, with the composition, mechanical properties and pitting resistance index you need to make a specification decision. Filter by family, or search for a grade, a UNS number or an application.
| Grade | UNS | Family | Composition (%) | Tensile | Yield | Elong. | PREN | Typical service |
|---|---|---|---|---|---|---|---|---|
| 304 | S30400 | Austenitic | C ≤0.08 · Cr 18.0–20.0 · Ni 8.0–10.5 | 515 | 205 | 40 | 18–20 | Food and water, kitchen equipment, general atmosphere, architectural panels |
| 304L | S30403 | Austenitic | C ≤0.03 · Cr 18.0–20.0 · Ni 8.0–12.0 | 485 | 170 | 40 | 18–20 | Heavily welded tanks, vessels and pipework; chemical process equipment |
| 316 | S31600 | Austenitic | C ≤0.08 · Cr 16.0–18.0 · Ni 10.0–14.0 · Mo 2.0–3.0 | 515 | 205 | 40 | 23–28 | Pulp and paper, mildly chlorinated water, dyestuffs, photographic equipment |
| 316L | S31603 | Austenitic | C ≤0.03 · Cr 16.0–18.0 · Ni 10.0–14.0 · Mo 2.0–3.0 | 485 | 170 | 40 | 24–26 | Chemical and pharmaceutical plant, desalination, marine hardware, process piping |
| 316Ti | S31635 | Austenitic | C ≤0.08 · Cr 16.0–18.0 · Ni 10.0–14.0 · Mo 2.0–3.0 · Ti 5×C | 515 | 205 | 40 | 24–26 | High-temperature chloride service, exhaust systems, expansion bellows |
| 317L | S31703 | Austenitic | C ≤0.03 · Cr 18.0–20.0 · Ni 11.0–15.0 · Mo 3.0–4.0 | 515 | 205 | 40 | 29–33 | Chloride and sulphite pulping, acetic and formic acid storage, flue-gas ducting |
| 321 | S32100 | Austenitic | C ≤0.08 · Cr 17.0–19.0 · Ni 9.0–12.0 · Ti 5×C | 515 | 205 | 40 | 17–19 | Heat exchangers, superheater tube, furnace parts to about 870 °C |
| 310S | S31008 | Austenitic | C ≤0.08 · Cr 24.0–26.0 · Ni 19.0–22.0 | 515 | 205 | 40 | 22–24 | Furnace linings, kilns, radiant tubes, high-temperature ducting and dampers |
| 904L | N08904 | Austenitic | C ≤0.02 · Cr 19.0–23.0 · Ni 23.0–28.0 · Mo 4.0–5.0 · Cu 1.0–2.0 | 490 | 220 | 35 | 34–38 | Sulphuric and phosphoric acid, fertiliser plants, acid tankers, scrubbers |
| 254SMO | S31254 | Austenitic | C ≤0.02 · Cr 19.5–20.5 · Ni 17.5–18.5 · Mo 6.0–6.5 · N 0.18–0.22 | 650 | 300 | 35 | 42–44 | Seawater and high-chloride environments, pulp bleaching, acid handling without duplex |
| 2304 | S32304 | Duplex | C ≤0.03 · Cr 21.5–24.5 · Ni 3.0–5.5 · N 0.05–0.20 | 600 | 400 | 25 | 24–26 | Lean duplex for pulp and paper, storage tanks, bridges and moderate chloride duty |
| 2205 | S32205 | Duplex | C ≤0.03 · Cr 22.0–23.0 · Ni 4.5–6.5 · Mo 3.0–3.5 · N 0.14–0.20 | 620 | 450 | 25 | 34–36 | Seawater and brine, desalination, sour gas gathering, chemical tankers, FGD |
| 2507 | S32750 | Super duplex | C ≤0.03 · Cr 24.0–26.0 · Ni 6.0–8.0 · Mo 3.0–5.0 · N 0.24–0.32 | 795 | 550 | 15 | 40–43 | Subsea and deepwater, high-chloride high-pressure service, seawater cooling, FGD absorbers |
| Zeron 100 | S32760 | Super duplex | C ≤0.03 · Cr 24.0–26.0 · Ni 6.0–8.0 · Mo 3.0–4.0 · Cu 0.5–1.0 · W 0.5–1.0 · N 0.20–0.30 | 750 | 550 | 25 | 40–43 | Tungsten-bearing super duplex for subsea manifolds, risers and seawater systems |
| 409 | S40900 | Ferritic | C ≤0.08 · Cr 10.5–11.75 · Ti stabilised | 380 | 170 | 20 | 11–13 | Automotive exhaust systems, agricultural equipment, low-duty enclosures |
| 430 | S43000 | Ferritic | C ≤0.12 · Cr 16.0–18.0 | 450 | 205 | 22 | 16–18 | Appliance panels, decorative trim, restaurant equipment, indoor cladding |
| 444 | S44400 | Ferritic | C ≤0.025 · Cr 17.5–19.5 · Mo 1.75–2.5 · Ti + Nb stabilised | 415 | 275 | 20 | 24–27 | Hot water tanks, solar thermal panels, coastal roofing and rainwater goods |
| 410 | S41000 | Martensitic | C ≤0.15 · Cr 11.5–13.5 | 480 | 275 | 16 | 11–13 | Valve trim, cutlery, pump parts, turbine blades, fasteners |
| 420 | S42000 | Martensitic | C ≥0.15 · Cr 12.0–14.0 | 655 | 345 | 15 | 13–15 | Blades, surgical instruments, plastic moulds, wear-resistant parts |
| 431 | S43100 | Martensitic | C ≤0.20 · Cr 15.0–17.0 · Ni 1.25–2.50 | 862 | 655 | 12 | 16–18 | High-strength shafts, bolts and aircraft structural parts |
| 17-4PH | S17400 / 630 | Precipitation hardening | C ≤0.07 · Cr 15.0–17.5 · Ni 3.0–5.0 · Cu 3.0–5.0 · Nb 0.15–0.45 | 1310 | 1170 | 10 | — | H900 condition — pump shafts, valve stems, gears, aerospace fittings |
| Alloy 400 | N04400 | Nickel alloy | Ni ≥63 · Cu 28.0–34.0 · Fe ≤2.5 | 480 | 170 | 40 | — | Hydrofluoric acid, seawater and marine fasteners, heat exchanger tube |
| Alloy 800H | N08810 | Nickel alloy | Cr 19.0–23.0 · Ni 30.0–35.0 · Al + Ti 0.30–0.80 | 450 | 170 | 30 | 20–22 | Cracking furnaces, reformer tube, high-temperature creep service |
| Alloy 825 | N08825 | Nickel alloy | Ni 38.0–46.0 · Cr 19.5–23.5 · Mo 2.5–3.5 · Cu 1.5–3.0 · Ti 0.6–1.2 | 585 | 240 | 30 | 29–31 | Sulphuric and phosphoric acid, sour gas, nuclear fuel reprocessing |
| Alloy 625 | N06625 | Nickel alloy | Ni ≥58 · Cr 20.0–23.0 · Mo 8.0–10.0 · Nb 3.15–4.15 | 830 | 415 | 30 | 51–53 | Seawater and sour gas, FGD ducting, subsea components, high-temperature fasteners |
| Alloy C-276 | N10276 | Nickel alloy | Ni balance · Cr 14.5–16.5 · Mo 15.0–17.0 · W 3.0–4.5 · Fe 4.0–7.0 | 690 | 283 | 40 | 68–70 | The most aggressive mixed acids and chlorides; flue-gas scrubbers, chemical reactors |
| Q235B | — | Carbon steel | C ≤0.20 · Si ≤0.35 · Mn ≤1.40 | 375–500 | ≥235 | 26 | — | General structural and fabrication; the most common clad plate base steel |
| Q345B / Q345R | — | Low-alloy steel | C ≤0.20 · Si ≤0.55 · Mn ≤1.70 | 490–675 | ≥345 | 21 | — | Higher-strength structures and pressure vessels; Q345R for vessel shells |
| ASTM A36 | K02600 | Carbon steel | C ≤0.25 · Si ≤0.40 · Mn 0.80–1.20 | 400–550 | ≥250 | 20 | — | Structural steel for American-standard projects; base plates and frames |
| A516 Gr.70 | K02700 | Pressure vessel steel | C ≤0.28 · Si 0.13–0.45 · Mn 0.85–1.20 | 485–620 | ≥260 | 21 | — | ASME pressure vessels and boilers — the standard clad plate base for vessels |
| API 5L X42 | — | Line pipe steel | C ≤0.26 · Mn ≤1.30 · micro-alloyed | ≥415 | 290–495 | 21 | — | Low-pressure gathering lines and general pipeline service |
| API 5L X65 | — | Line pipe steel | C ≤0.26 · Mn ≤1.45 · Nb / V / Ti micro-alloyed | ≥535 | 450–600 | 18 | — | High-pressure oil and gas transmission; the standard clad pipe carrier steel |
| API 5L X80 | — | Line pipe steel | C ≤0.24 · Mn ≤1.60 · Nb / V / Ti micro-alloyed | ≥625 | 555–705 | 16 | — | Large-diameter, high-pressure long-distance pipelines |
| 20G / 20R | — | Boiler steel | C 0.17–0.24 · Si 0.17–0.37 · Mn 0.35–0.65 | 410–550 | ≥245 | 24 | — | Boiler and pressure piping; common base for clad pipe in power plants |
Notes. Composition values are typical specification ranges, not heat analyses. Tensile, yield and elongation figures are minimum values for the annealed or solution-treated condition to ASTM E8 / E8M and the relevant product standard. PREN is the Pitting Resistance Equivalent Number, calculated as Cr + 3.3 Mo + 16 N; it is an indicative ranking for chloride service, not a design value. Always confirm the final grade, condition and tolerances against the material certificate issued for your order.
You do not need the chemistry to buy steel, but knowing what drives the price and what drives the performance makes the specification conversation much shorter.
PREN ranks grades by their resistance to pitting in chloride environments. As a rough guide: below 25 is fine for fresh water and mild conditions; 25 to 35 suits brackish water and moderate chlorides; 35 to 40 is the entry point for ambient-temperature seawater; above 40 is what you specify for seawater at elevated temperature, and for sour service. The formula does not account for temperature, acidity or flow, so treat it as a starting filter rather than a final answer.
Medium, chloride level, operating temperature and pressure — send us those four things and we will specify the grade, the form and the finish, and tell you where a cheaper option would do the same job.
