§ 1
What is NiCr33Mo8, and what is it equivalent to?
NiCr33Mo8 is a wrought nickel alloy specified under DIN 17744, the German standard covering nickel alloys with molybdenum and chromium. The name encodes the chemistry directly: nickel base, nominally 33 % chromium, 8 % molybdenum. It is a solid-solution strengthened alloy, meaning it takes its strength from alloying elements dissolved in the nickel matrix rather than from a precipitation-hardening heat treatment.
| System | Designation | Notes |
|---|---|---|
| DIN / EN name | NiCr33Mo8 | DIN 17744 |
| Werkstoff no. | 2.4643 | EN numeric designation |
| UNS | N06035 | ASTM / ASME tables |
| Trade name | HASTELLOY® G-35® | Haynes International trademark, see notice below |
| Common shorthand | Alloy 35, Alloy G-35 | Market usage |
| Cast equivalent | G35C | Foundry grade, for reference only |
| Welding consumables | ERNiCrMo-22 / ENiCrMo-22 | AWS A5.14 wire / A5.11 electrode |
Trademark notice. HASTELLOY® G-35® is a registered trademark of Haynes International, Inc.. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with, sponsored by or endorsed by that company. Trade names appear here only to identify the equivalent specification a buyer may be working to.
§ 2
Chemical composition of NiCr33Mo8 (2.4643 / N06035)
The chromium level is what sets this grade apart. At about 33 %, it is roughly half again as much chromium as Alloy 625 and twice that of C-276, which is why it holds up in oxidising acids where higher-molybdenum alloys do not.
| Element | Ni | Cr | Mo | Fe | Co | W | Mn | Si | Al | Cu | C |
|---|---|---|---|---|---|---|---|---|---|---|---|
| wt % | 58 bal. | 33.2 | 8.1 | 2.0 max | 1.0 max | 0.6 max | 0.5 max | 0.6 max | 0.4 max | 0.3 max | 0.05 max |
Derived figurePitting resistance equivalent number, PREN = %Cr + 3.3 × %Mo = 33.2 + (3.3 × 8.1) ≈ 60, calculated from the nominal composition above. Nitrogen is not a specified addition in this grade, so the 16 × %N term is omitted.
§ 3
Mechanical and physical properties
Two sets of numbers matter when you buy a forging. The specification minima are what the mill certificate has to beat. The typical values tell you what the material actually does. Both are given below.
| Basis | 0.2 % yield | Tensile | Elongation | Hardness |
|---|---|---|---|---|
| ASTM B564 / SB-564 minimum (forgings) | 241 MPa (35 ksi) | 586 MPa (85 ksi) | 30 % min | — |
| Typical, 25 mm (1 in) bar | 317 MPa (46 ksi) | 710 MPa (103 ksi) | 66 % | 82 HRBW |
| Typical, 12.7 mm plate | 317 MPa (46 ksi) | 689 MPa (100 ksi) | 72 % | 87 HRBW |
| Test temperature | 0.2 % yield | Tensile | Elongation |
|---|---|---|---|
| 93 °C (200 °F) | 283 MPa | 676 MPa | 70 % |
| 204 °C (400 °F) | 241 MPa | 614 MPa | 71 % |
| 316 °C (600 °F) | 207 MPa | 579 MPa | 71 % |
| 427 °C (800 °F) | 214 MPa | 558 MPa | 73 % |
| 538 °C (1000 °F) | 193 MPa | 517 MPa | 72 % |
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.22 g/cm³ | 0.297 lb/in³ |
| Melting range | 1332–1361 °C | 2430–2482 °F |
| Modulus of elasticity, RT | 204 GPa | 29.6 × 106 psi |
| Thermal conductivity, RT | 10 W/m·°C | 70 Btu·in/h·ft²·°F |
| Mean CTE, 21–100 °C | 12.3 µm/m·°C | 6.8 µin/in·°F |
| Electrical resistivity, RT | 1.18 µΩ·m | 46.5 µΩ·in |
| Charpy V-notch, RT | 503 J | 371 ft·lbf |
| Charpy V-notch, −196 °C | 625 J | 461 ft·lbf |
| ASME VIII Div. 1 max. design temp. | 427 °C | 800 °F |
Property values are drawn from the alloy originator's published datasheet for UNS N06035 and from ASTM B564. They are indicative and are not design allowables. Confirm against the governing specification edition and your own qualification testing.
§ 4
Why engineers specify NiCr33Mo8: corrosion performance
This grade was developed for one job in particular: wet-process phosphoric acid, the impure P2O5 made by digesting phosphate rock with sulfuric acid for fertiliser production. That acid carries fluoride and chloride ions, and chlorides are what destroy most stainless steels beneath evaporator deposits. NiCr33Mo8 was designed around that problem.
| Alloy | Critical pitting temp. | Critical crevice temp. |
|---|---|---|
| NiCr33Mo8 / N06035 | 95 °C (203 °F) | 45 °C (133 °F) |
| Alloy 625 / N06625 | 100 °C (212 °F) | 40 °C (104 °F) |
| Alloy G-30 / N06030 | 67.5 °C (154 °F) | 37.5 °C (100 °F) |
| 254 SMO | 60 °C (140 °F) | 30 °C (86 °F) |
| 316L stainless | 15 °C (59 °F) | 0 °C (32 °F) |
| Alloy | Time to cracking |
|---|---|
| NiCr33Mo8 / N06035 | No cracking in 1,008 h |
| Alloy 625 / N06625 | No cracking in 1,008 h |
| Alloy G-30 / N06030 | 168 h |
| 254 SMO | 24 h |
| 316L stainless | 2 h |
Behaviour in common process chemicals
- Phosphoric acid. Corrosion rates stay at or below 0.01 mm/y in boiling 50–60 % acid, rising to about 0.14 mm/y at 85 % and 121 °C. This is the grade's home ground.
- Nitric and other oxidising acids. Approximately 0.01 mm/y in boiling 40 % nitric and about 0.1 mm/y in boiling 70 %, a direct result of the high chromium.
- Hot sodium hydroxide. Unusually resistant to caustic de-alloying compared with other Ni-Cr-Mo alloys.
- Reducing acids (HCl, H2SO4). Moderate resistance only, from the 8 % molybdenum. If hydrochloric acid dominates your service, C-276 or C-22 is usually the better choice.
- Welds. All-weld-metal corrosion resistance is close to that of the wrought base metal in the key inorganic acids.
Corrosion rates quoted above are laboratory results in reagent-grade acids and are indicative only. Real process streams contain impurities that change behaviour. Field testing before industrial use is strongly recommended.
§ 5
How Jiangnan Metal forges NiCr33Mo8
NiCr33Mo8 is not a forgiving forging alloy. The hot-working window is narrow and the alloy is more sensitive to strain and strain rate than austenitic stainless steel. That means moderate reductions, frequent reheats and a controlled anneal afterwards.
| Step | Parameter |
|---|---|
| 1. Billet | Traceable billet or ingot, with the melt route recorded on the mill certificate. State any specific requirement, for example VIM + ESR, on the enquiry. |
| 2. Heating | Controlled soak in a calibrated furnace. Chart records supplied on request. |
| 3. Open-die forging | Start about 1204 °C (2200 °F), finish about 954 °C (1750 °F). Moderate reductions with reheats between passes. |
| 4. Ring rolling | Seamless rolled rings produced from upset and punched blanks, giving continuous circumferential grain flow. |
| 5. Solution anneal | Approximately 1121 °C (2050 °F), hold 10–30 min according to section thickness, then water quench. No ageing treatment, see the note below. |
| 6. Cold work control | Re-anneal after any cold forming producing 7 % or more outer-fibre elongation, to restore stress corrosion cracking resistance. |
| 7. Machining | Rough or finish machining to drawing. The alloy work hardens readily, so we use rigid setups, positive rake and generous feed. |
| 8. NDT and release | Ultrasonic and dye-penetrant testing, dimensional report, certification. See § 8. |
Common specification errorNiCr33Mo8 / UNS N06035 is not a precipitation-hardening alloy. It is supplied solution annealed only. Specifying "solution treat plus age" on this grade is incorrect: holding it in the 593–649 °C range measurably reduces weld-metal impact toughness. If your drawing calls for ageing, tell us and we will query it before cutting metal.
§ 6
NiCr33Mo8 forged shapes and size range
Everything below is made to a customer drawing. There is no standard catalogue, so send dimensions and we confirm feasibility against press, ring mill and furnace capacity.
| Shape | Size capability | Typical use |
|---|---|---|
| Seamless rolled rings | OD to 4,000 mm and above | Vessel and column shell courses, valve seat rings |
| Forged rings, sleeves, bushings | OD to 4,000 mm and above | Pump wear rings, spacers, liners |
| Discs, blanks, tube sheets | OD to 4,000 mm and above | Heat exchanger tube sheets, closures, blind covers |
| Flanges | ASME B16.5, B16.47 Series A and B, EN 1092-1, JIS B2220, plus non-standard to drawing | Pressure vessels, piping, valves |
| Round bars, billets, hollow bars | Forged to drawing | Valve stems, fasteners, machining stock, nozzles |
| Shafts and spindles | Forged to drawing | Chemical and plunger pumps, agitators |
| Valve bodies, seat rings, blocks | Forged to drawing | Ball, gate, globe, check and plug valves |
| All shapes: single-piece weight | 15,000 kg and above | Heavier pieces confirmed on enquiry |
§ 7
Where NiCr33Mo8 forgings are used
| Industry | Typical forged components |
|---|---|
| Fertiliser and phosphates | P2O5 evaporator components, tube sheets, flanges, pump parts in wet-process phosphoric acid |
| Chemical process | Reactor nozzles, columns and towers, heat exchanger tube sheets, agitator shafts, crystalliser parts |
| Nitric acid and oxidising service | Flanges, rings, valve bodies and internals |
| Chlor-alkali and caustic | Components exposed to hot sodium hydroxide where de-alloying is a concern |
| Oil and gas, offshore | Wellhead and Christmas tree parts, subsea components, sour-service items to NACE MR0175 |
| Pressure equipment | Forged flanges, tube sheets, shell rings, nozzles for vessels and shell-and-tube exchangers |
| Valves | Bodies, bonnets, stems, seat rings, discs and plugs for ball, gate, globe, check and plug valves |
| Pulp, paper and pharmaceutical | Digester and bleach-plant parts, hygienic process components |
§ 8
Standards, testing and certification
| Item | Specification |
|---|---|
| Forgings | ASTM B564 / ASME SB-564; ASTM B462 / SB-462 (flanges, fittings, valves for high-temperature service) |
| Bar and billet | ASTM B574 / SB-574; ASTM B472 (billet) |
| Plate, sheet, strip | ASTM B575 / SB-575 |
| Seamless pipe and tube | ASTM B622 / SB-622 |
| Fittings | ASTM B366 / SB-366 |
| Chemistry | DIN 17744 (NiCr33Mo8) or the ASTM table on the order |
| Flange dimensions | ASME B16.5, ASME B16.47, EN 1092-1, JIS B2220, GOST 12820/12821 |
| Sour service | NACE MR0175 / ISO 15156. Confirm the applicable table and hardness limits for your part |
| Code acceptance | ASME Code Case 2484; ASME VIII Div. 1 and B31.3 to 427 °C (800 °F) |
| Ultrasonic testing | ASTM A388 / ASME SA-388, or EN 10228-3 / SEP 1921 by agreement |
| Surface NDT | Liquid penetrant to ASTM E165 / ASME Section V |
| Corrosion test | Intergranular corrosion to ASTM G28 Method A on request |
| Certification | EN 10204 3.1 as standard; third-party EN 10204 3.2 on request |
§ 9
NiCr33Mo8 versus other Ni-Cr-Mo grades
Select by service chemistry rather than by price per kilo. Chromium buys resistance to oxidising conditions, molybdenum buys resistance to reducing conditions, and the two trade off against each other.
| Grade | Cr | Mo | Strongest in |
|---|---|---|---|
| NiCr33Mo8 (2.4643 / N06035) | 33.2 | 8.1 | Wet-process phosphoric acid, nitric and oxidising acids, hot caustic |
| Alloy 625 (2.4856 / N06625) | 21.5 | 9 | General purpose, seawater, high strength, wide code coverage |
| C-276 (2.4819 / N10276) | 16 | 16 | Reducing acids, hydrochloric, mixed acid, sulfuric |
| C-22 (2.4602 / N06022) | 22 | 13 | Mixed oxidising and reducing service, versatile |
| Alloy 59 (2.4605 / N06059) | 23 | 16 | Flue gas desulphurisation, aggressive mixed acid |
| G-3 / G-30 family | 22–30 | 5–7 | Commercial phosphoric acid, the predecessors to this grade |
| Alloy 825 (2.4858 / N08825) | 21.5 | 3 | Lower-cost option for milder sulfuric and phosphoric service |
We forge all of the grades above. Related pages:
§ 10
Request a NiCr33Mo8 quotation
Send the items below and you will get a firm price rather than a range. Missing information is the single biggest cause of slow quotes on nickel alloy forgings.
- Drawing or dimensions. 2D PDF or DWG, or 3D STEP. Rough forging dimensions are fine if you have no drawing.
- Quantity and whether this is a one-off, a project lot or a call-off.
- Governing specification, for example "ASTM B564 UNS N06035, solution annealed".
- Supply condition. As-forged, rough machined with allowance, or finish machined.
- NDT requirement. UT acceptance class, PT, and whether ASTM G28 testing is required.
- Certificate. EN 10204 3.1, or third-party 3.2 and which inspection body.
- Delivery. Required date, Incoterms and destination port.
§ 11
Frequently asked questions about NiCr33Mo8
What is NiCr33Mo8?
NiCr33Mo8 is the DIN designation for a low-carbon nickel-chromium-molybdenum alloy with material number 2.4643 and UNS number N06035. Nominal composition is about 58 % nickel, 33.2 % chromium and 8.1 % molybdenum. The high chromium gives strong resistance to oxidising acids and wet-process phosphoric acid, while the molybdenum adds moderate resistance to reducing acids. Jiangyin Jiangnan Metal Co., Ltd. supplies it as open-die forgings.
What is NiCr33Mo8 equivalent to?
NiCr33Mo8 equals W.-Nr. 2.4643 under DIN 17744 and UNS N06035 in ASTM and ASME specifications. It is the grade sold commercially as HASTELLOY® G-35® alloy. Forgings are ordered to ASTM B564 / SB-564 or ASTM B462, bar to ASTM B574, plate to ASTM B575 and seamless pipe to ASTM B622.
Can NiCr33Mo8 be age hardened?
No. NiCr33Mo8 is solid-solution strengthened, not precipitation hardening, so it is supplied solution annealed with no ageing step. The recommended anneal is approximately 1121 °C (2050 °F) with a 10 to 30 minute hold followed by water quenching. Holding the alloy in the 593 to 649 °C range measurably reduces weld-metal impact toughness and should be avoided.
What is the forging temperature range for NiCr33Mo8?
Start hot forging at about 1204 °C (2200 °F) and finish at about 954 °C (1750 °F). The window is narrow and the alloy is sensitive to strain rate, so Jiangyin Jiangnan Metal forges in moderate reductions with frequent reheats, then re-anneals after hot working to restore corrosion resistance and ductility.
How does NiCr33Mo8 compare with Alloy 625 and C-276?
NiCr33Mo8 carries about 33 % chromium against roughly 21 % in Alloy 625 and 16 % in C-276, so it is stronger in oxidising acids such as nitric, in wet-process phosphoric acid, and against caustic de-alloying in hot sodium hydroxide. C-276 and C-22 carry more molybdenum and perform better in reducing acids such as hydrochloric. Select on service chemistry rather than nickel content.
Which standards cover NiCr33Mo8 forgings?
Forgings are normally ordered to ASTM B564 / ASME SB-564 or ASTM B462, which require a minimum tensile strength of 586 MPa (85 ksi), minimum 0.2 % yield of 241 MPa (35 ksi) and 30 % minimum elongation, solution annealed. Chemistry follows DIN 17744 or the ASTM table. The grade appears in NACE MR0175 / ISO 15156 and ASME Code Case 2484.
What size NiCr33Mo8 forgings can Jiangyin Jiangnan Metal produce?
Single pieces of 15,000 kg and above, with ring and disc outside diameters of 4,000 mm and above. Shapes include seamless rolled rings, forged rings, flanges, round bars, discs and blanks, shafts and spindles, sleeves and bushings, tube sheets, nozzles, and valve bodies, stems and seat rings, all made to a customer drawing. Send a 2D or 3D drawing to sales@steelforgepieces.com for confirmation.
What information is needed to quote a NiCr33Mo8 forging?
The drawing or finished dimensions, quantity, governing specification, supply condition, required NDT such as ultrasonic testing to ASTM A388, any ASTM G28 intergranular corrosion test, the certificate type (EN 10204 3.1 or third-party 3.2), and your delivery date and destination. Email sales@steelforgepieces.com or call +86-189-2135-9659.
§ 12
Supplier
Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory producing forged rings, seamless rolled rings, flanges, bars, discs, shafts, sleeves, bushings, tube sheets and nozzles in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, in single pieces of 15,000 kg and above, made to customer drawings for export worldwide.
AddressNo.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China
Telephone and WhatsApp+86-189-2135-9659
Emailsales@steelforgepieces.com
Websitewww.steelforgepieces.com
Jiangyin Jiangnan Metal Co., Ltd. (2026) "NiCr33Mo8 forgings, W.-Nr. 2.4643 / UNS N06035." https://www.steelforgepieces.com/Nickel-Alloy/NiCr33Mo8.htmlReferences
- Haynes International, HASTELLOY® G-35® alloy, Principal Features, document H-2121D. Source of nominal composition, physical properties, tensile data, ASTM G48 and G36 results, and forging and annealing temperatures. haynesintl.com
- ASTM International, ASTM B564 Standard Specification for Nickel Alloy Forgings. Source of minimum mechanical properties for UNS N06035 forgings. astm.org
- DIN, DIN 17744 Wrought nickel alloys with molybdenum and chromium, Chemical composition. Source of the NiCr33Mo8 designation and material number 2.4643.
- ASTM International, ASTM G48 (pitting and crevice, ferric chloride) and ASTM G36 (stress corrosion cracking, boiling magnesium chloride) test methods.
Disclaimer. The technical values on this page are compiled from the alloy originator's published literature and public standards for the convenience of engineers and buyers. They are indicative, not guaranteed minima or maxima, and are not design allowables. Properties of a specific forging depend on section size, heat treatment and heat chemistry, and are stated on the mill certificate supplied with the goods. Users are responsible for testing under actual service conditions to confirm suitability. Page last reviewed by Jiangyin Jiangnan Metal Co., Ltd..