Nickel-Based Alloys
For corrosion resistance, elevated-temperature strength and demanding process environments.
SPECIALTY ALLOYS
Performance starts with the material.
High-performance alloys supplied in standard and custom forms, with specification-driven documentation and traceability requirements.
Nickel
625 · 718 · 725 · 825 · C-276 · Alloy 22 · X-750
Duplex
2205 · 2507
Superaustenitic
904L · 254 SMO · AL-6XN · 926 · 654 SMO
Titanium
Gr.2 · Gr.5 · Gr.7 · Gr.12 · Gr.23
PH stainless
17-4PH · 15-5PH · 17-7PH
Forms
Bar · Plate · Tube · Pipe · Ring · Disc · Forging · Billet · Cut-to-size
Sixteen are set out below against the product specifications that apply to each form. Nine of those carry a second table as well — mechanical minima, heat-treatment route, and the failure mode that grade actually presents. The rest we quote on enquiry.
IF YOUR DRAWING SAYS SOMETHING ELSE
Trade name, UNS number,
and what we call it.
Most drawings arrive carrying a mill’s trade name. Those names belong to the mills that own them, and material from any other source — however exactly it meets the same UNS number and the same ASTM specification — is not that trademarked product and should not be quoted as though it were. So we quote against the UNS number and the product specification. For the superaustenitic grades in particular there is no established generic name in common use, which is exactly why the UNS number — not the trade name — is what goes on our quote and on the certificate. Here is the mapping, so nothing is lost between your drawing and that quote.
| Your drawing may say | The designation underneath it | What we quote | Mark owned by |
|---|---|---|---|
| INCONEL® 625 | UNS N06625 | Alloy 625 | Special Metals |
| INCONEL® 718 | UNS N07718 | Alloy 718 | Special Metals |
| INCONEL® 725 | UNS N07725 | Alloy 725 | Special Metals |
| INCONEL® X-750 | UNS N07750 | Alloy X-750 | Special Metals |
| INCOLOY® 825 | UNS N08825 | Alloy 825 | Special Metals |
| INCOLOY® 25-6MO | UNS N08926 · 1.4529 | Alloy 926 | Special Metals |
| HASTELLOY® C-276 | UNS N10276 · 2.4819 | Alloy C-276 | Haynes |
| HASTELLOY® C-22® | UNS N06022 · 2.4602 | Alloy 22 | Haynes |
| 254 SMO® | UNS S31254 · 1.4547 | UNS S31254 | Outokumpu |
| 654 SMO® | UNS S32654 · 1.4652 | UNS S32654 | Outokumpu |
| AL-6XN® | UNS N08367 | UNS N08367 | ATI |
| 17-4 PH | UNS S17400 · 1.4542 | 17-4PH | — no current mark |
A trade name on a drawing is usually sitting on top of a real specification.
“INCONEL 718 PER AMS 5662” is an AMS 5662 requirement with a producer’s name attached, and that is straightforward to quote. But if your approved mill list or your end client’s specification genuinely requires that producer’s material, say so at RFQ — that is a sourcing constraint rather than a wording preference, and it changes what can be quoted at all. The other one worth catching early is a drawing carrying only a trade name and no governing specification — there is no acceptance basis in that, and the gap is cheaper to close at RFQ than at receiving inspection.
Alloy families
Duplex & Specialty Stainless
High-strength corrosion-resistant stainless grades for aggressive chloride and process environments, plus the precipitation-hardening grades.
Titanium Alloys
Unalloyed and alloyed titanium — for oxidizing chloride and seawater duty where stainless runs out, and for strength at low density where the application is weight-driven.
Product forms: Bar · Plate · Pipe · Tube · Ring · Disc · Forging · Billet · Cut-to-size · Custom sizes
GRADE REFERENCE
Sixteen grades, specification by specification.
The grades quoted most often, each against the product specifications cited on North American enquiries. A grade name on its own is not a purchase specification — the governing standard, its edition and the product form decide the acceptance basis.
| Grade | Family | PREN | Common product specifications | Where it is normally used |
|---|---|---|---|---|
| Alloy 625UNS N06625 | Ni-Cr-Mo-Nb, solid-solution strengthened | ≈50 (indicative) | B446/SB446 bar · B564/SB564 forgings · B443/SB443 plate · B444/SB444 tube · AWS A5.14 ERNiCrMo-3 | Offshore piping and fasteners, sour gas-field valve components, FGD system parts, LNG low-temperature piping |
| Alloy 718UNS N07718 | Ni-Fe-Cr, γ″ precipitation hardened | n/a | B637/SB637 bar, forgings & rings (industrial) · AMS 5662 solution treated · AMS 5663 solution treated + double aged (aerospace). Both AMS specifications cover bar, forgings and rings — what separates them is the delivered heat-treatment condition, not the product form | High-strength fasteners, compressor and pump shafts, impeller blanks, high-temperature rotating components — non-sour service |
| Alloy C-276UNS N10276 · 2.4819 | Ni-Cr-Mo-W, low carbon and silicon, solid-solution | ≈68 (indicative) | B574/SB574 bar & rod · B564/SB564 forgings · B575/SB575 plate, sheet & strip · B622/SB622 seamless pipe & tube · B619 welded pipe · B626 welded tube · B366 fittings · AWS A5.14 ERNiCrMo-4 | Flue-gas desulphurization, chlorinated and mixed acids, sour service to MR0175/ISO 15156, pulp bleaching, and valve trim and seats where 625 has run out. The reducing-media workhorse of the C family |
| Alloy 22UNS N06022 · 2.4602 · also specified as C-22 | Ni-Cr-Mo-W, higher Cr and lower Mo than C-276 | ≈66 (indicative) | B574/SB574 bar & rod · B564/SB564 forgings · B575/SB575 plate, sheet & strip · B622/SB622 seamless pipe & tube · B619 welded pipe · B626 welded tube · B366 fittings · AWS A5.14 ERNiCrMo-10 | Where the medium swings between oxidizing and reducing and one alloy has to cover both. The higher chromium buys the oxidizing side that C-276 gives up, and pays for it in molybdenum — so it is not a substitution in either direction. On a non-Haynes heat the designation is alloy 22; C-22 is a trade name |
| Duplex 2205UNS S32205 / S31803 | Ferritic-austenitic duplex | ≈34–36 | A182 Grade F51 forgings · A276/A479 bar · A815 fittings · A240 plate · AWS A5.9 ER2209 | Valve bodies, flanges and piping in moderately corrosive service; desalination and cooling; moderate-chloride process piping |
| Super duplex 2507UNS S32750 | Super duplex, PREN ≥40 class | ≈40–42 | A182 Grade F53 forgings · A276/A479 bar · A815 fittings · A240 plate · AWS A5.9 ER2594 | Subsea pipelines and production equipment, high-chloride and high-salinity service, deepwater high-pressure components |
| 904LUNS N08904 · 1.4539 | High Ni-Mo-Cu austenitic | ≈34–36 | A240/SA-240 plate · A312 pipe · A213/A269 tube · A276/A479 bar · B677 seamless | Selected sulfuric and phosphoric acid duty and reducing-acid environments |
| 254 SMOUNS S31254 · 1.4547 | 6Mo + N superaustenitic | ≥42.5 | A182 F44 forgings/flanges · A240 plate · A312/A213/A269 seamless · A249/A358/A409 welded | Seawater and high-chloride service. F44 on an enquiry is a forging requirement, not a plate substitution |
| AL-6XNUNS N08367 | 6Mo superaustenitic, Ni 23.5–25.5% | state formula | A240 / B688 · SA-240 / SB-688 plate, sheet, strip · B690 seamless pipe and tube · B675 welded pipe · B676 welded tube · B691 rod, bar and wire | The principal North American 6Mo route. PREN may be quoted on a 30N or a 16N formula — the RFQ must say which |
| Alloy 926UNS N08926 · 1.4529 | 6Mo + Cu superaustenitic | >40 class | A240/SA-240 plate · other forms per producer scope · NORSOK M-650 / MDS | Mixed acid-plus-chloride media. Shares the EN 1.4529 market with N08367 but not its UNS identity or qualification |
| 654 SMOUNS S32654 · 1.4652 | ≈7Mo, high-N superaustenitic | very high | Flat product to UNS S32654 · other forms per producer scope | Extreme localized corrosion. Selected by corrosion engineering, never as a routine upgrade from 2507 or 625 |
| Titanium Grade 2UNS R50400 | Unalloyed (commercially pure) titanium | n/a | B348 bar & billet · B381 forgings · B265 plate, sheet & strip · B338 tube · B861 seamless pipe · B862 welded pipe · B363 fittings | Seawater and oxidizing chloride duty — condensers, coolers, heat exchangers. Crevice-corrosion resistance depends on temperature, pH, aeration and crevice geometry together; suitability is confirmed against the actual service environment, not against the grade |
| Titanium Grade 5Ti-6Al-4V · UNS R56400 | α-β alloy, heat treatable | n/a | B348 bar & billet · B381 forgings · B265 plate · AMS 4928 bar, wire, forgings & rings (annealed) · AMS 4965 (solution treated and aged, to 4″) | The structural titanium. Compressor impellers and rotating parts where strength at low density governs rather than corrosion |
| Titanium Grade 7Ti-0.15Pd · UNS R52400 | Palladium-alloyed unalloyed titanium | n/a | B348 bar & billet · B381 forgings · B265 plate, sheet & strip · B338 tube · B861 / B862 pipe | Where Grade 2 reaches its corrosion limit. The palladium addition extends resistance to crevice attack and to reducing conditions; the allowable envelope is confirmed against the specific medium, temperature and pH. Bought for the environment, not for strength — the mechanical minima are Grade 2’s |
| Titanium Grade 12Ti-0.3Mo-0.8Ni · UNS R53400 | Mo-Ni alloyed titanium | n/a | B348 bar & billet · B381 forgings · B265 plate, sheet & strip · B338 tube | Crevice resistance beyond unalloyed titanium without palladium pricing, and a higher yield than Grade 2. Selected by corrosion engineering against the specific medium |
| Titanium Grade 23Ti-6Al-4V ELI · UNS R56407 | α-β, extra-low interstitial | n/a | B348 bar & billet · B381 forgings · B265 plate · AMS specifications per application | Where fracture toughness and low-temperature ductility govern. Lower interstitials also mean lower guaranteed strength than Grade 5 — substituting ELI is a change of property set, not an upgrade |
PREN = %Cr + 3.3 × %Mo + 16 × %N. It is a chemistry-derived comparative index for chloride pitting — not a corrosion rate, not a permitted service temperature, and not an H₂S cracking acceptance criterion. For real selection it belongs alongside CPT/CCT data (ASTM G48 series), phase balance, weld condition and the actual service envelope. Nickel-base alloys such as 625 should not be ranked against stainless steels on PREN alone, and it does not apply to titanium at all — titanium resists chlorides through a passive oxide film, not through a Cr-Mo-N chemistry balance, so there is no PREN figure to compare.
Specification numbers here are a map, not a controlled document.
Editions are revised and individual standards are occasionally withdrawn or superseded. The governing specification, its edition year and its current status are confirmed against the live ASTM, ASME or producer listing at RFQ stage — and written into the purchase order — before anything is priced.
CORE GRADES IN DETAIL
Properties, heat treatment,
and what goes wrong.
Typical values in the condition stated. The final column is the part most enquiries leave out — and the part that decides whether a batch is genuinely acceptable.
| Grade | Tensile | Yield 0.2% | Elong. | Heat-treatment route | Principal risk |
|---|---|---|---|---|---|
| Alloy 625Grade 1 — annealed | ≥827 MPa | ≥414 MPa | ≥30% | Anneal from ≈871 °C | The standard stocked condition. Minima fall with section size — 60 ksi yield to 4″, 50 ksi to 10″ |
| Alloy 625Grade 2 — solution annealed | ≥690 MPa | ≥276 MPa | ≥30% | Solution anneal from ≈1093 °C | Lower strength bought deliberately for high-temperature stability and creep service. Grade 1 and Grade 2 are not interchangeable |
| Alloy 718Solution + double aged | ≥1241 MPa | ≥1034 MPa | ≥12% | Two accepted routes. Low solution ≈925–1010 °C, or high solution ≈1040–1065 °C — each followed by its own aging schedule, since temperature, hold time and total cycle differ between the two. The governing specification sets the pairing | The route is a specification decision, not a default. Low solution gives the finest grain, highest room-temperature strength and best fatigue and rupture life; high solution gives better transverse ductility and impact in heavy sections but tends toward notch brittleness in stress rupture |
| Alloy C-276Solution annealed | ≥690 MPa | ≥283 MPa | ≥40% | Solution anneal ≈1121 °C, rapid quench mandatory. There is no aging step — strength and corrosion resistance both come out of the solution-annealed condition rather than from any subsequent cycle | Both grades were designed to be used as-welded — the very low carbon and silicon are what keep grain-boundary precipitation out of the heat-affected zone, and most welded work ships with no post-weld solution anneal. So the risk is not welding as such: it is heavy section, high heat input, slow cooling, or any extended hold in roughly 600–1000 °C, where mu phase and carbides do form. Chemistry passes and hardness passes while the corrosion resistance is already gone. ASTM G28 Method A is what finds it — and G28 carries no built-in acceptance limit, so a maximum corrosion rate has to be written into the purchase order or the test proves nothing |
| Alloy 22Solution annealed | ≥690 MPa | ≥310 MPa | ≥45% | Solution anneal ≈1121 °C, rapid quench mandatory. There is no aging step — strength and corrosion resistance both come out of the solution-annealed condition rather than from any subsequent cycle | The same precipitation mechanism as C-276 and the same G28 requirement. Alloy 22 tolerates the as-welded condition better still, which is usually the real reason it gets specified — but “better in the weld” is a G28 result on the delivered heat, not a property of the grade name |
| Duplex 2205Solution annealed | ≥620 MPa | ≥450 MPa | ≥25% | Solution ≈1020–1100 °C, water quench mandatory | Sigma phase on any dwell in the 600–1000 °C band — chemistry and hardness can pass while impact testing fails |
| Super duplex 2507Solution annealed | ≥795 MPa | ≥550 MPa | ≥15% | Solution ≈1025–1125 °C, water quench mandatory | MR0175 ceiling of 32 HRC does not stand alone — sigma control is the harder half of acceptance |
| Titanium Grade 2Mill annealed | ≥345 MPa | ≥275 MPa | ≥20% | Mill anneal only. Unalloyed titanium is not strengthened by heat treatment — the condition is set in working, not in a furnace cycle | Hydrogen, picked up from improper pickling. Above ≈80 °C it is also open to hydrogen embrittlement where it is galvanically coupled to a more active metal, under impressed current, or at pH below 3 or above 12. Less susceptible than the high-strength alloys, not immune |
| Titanium Grade 5Ti-6Al-4V — annealed minima | ≥895 MPa | ≥828 MPa | ≥10% | Mill anneal ≈690–760 °C, ½–2 h, air or furnace cool. Where strength is wanted: solution ≈913–954 °C, 1 h, water quench, then age ≈524–552 °C, 4–8 h, air cool. Beta transus ≈999 °C ± 14 is the ceiling every thermal step stays under unless a beta anneal is specified on purpose | Three different things are called Grade 5. ASTM B348 annealed requires ≥895/828 MPa; AMS 4928 requires ≥931/862 MPa on bar to 2″; AMS 4965 solution treated and aged requires ≥1138/1069 MPa to 4″. And STA response falls away with section size — the condition has to be achievable in the part, not only in a test bar |
Condition is part of the order, not an afterthought.
For 718, solution annealed and solution-plus-aged are two different products; the two solution routes above produce different property sets from the same chemistry, and each carries its own aging schedule rather than a shared one. For 625, Grade 1 and Grade 2 carry different guaranteed minima. Minimum values also fall with increasing section size, and the governing product specification and its edition decide the actual acceptance figures. Stating only a grade and a dimension is not enough to quote against.
Titanium fails in ways the nickel alloys do not.
Oxygen, nitrogen and carbon are picked up during forging, heat treatment and brazing and form a hard, brittle surface layer — alpha case — which has to be removed by machining or pickling and does not appear on a chemistry certificate. Hydrogen is picked up from improper pickling. Both cut ductility and worsen notch sensitivity. Titanium is also not a universal upgrade: it is not used in fluorides, strong reducing acids, very strong caustics, anhydrous chlorine, or pure oxygen service. A grade that outlasts 2507 in seawater can fail in a medium 2507 tolerates, so the enquiry has to carry the environment, not only the grade.
Specification-led supply
Standards & designations
Supply can be evaluated against customer-required ASTM, ASME, AMS, UNS, EN or other applicable material specifications.
Documentation
Material traceability, heat/lot identification, MTRs and project-specific testing or inspection documentation can be defined at RFQ stage.
Final grade, condition, dimensions, testing and acceptance criteria should be confirmed from the customer drawing, purchase specification and service requirements.
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