Nickel alloy / Open-die forgings

NiCr23Mo16Cu Forgings

Alloy C-2000 · UNS N06200 · W.Nr. 2.4675 · DIN 17744

NiCr23Mo16Cu is the EN/DIN chemical designation for a low-carbon nickel-chromium-molybdenum alloy containing approximately 23 % chromium, 16 % molybdenum and 1.6 % copper, with nickel as the balance. It is registered as UNS N06200 and Werkstoff 2.4675. The copper addition raises resistance to sulfuric acid above that of conventional Ni-Cr-Mo grades. The 23 % chromium content maintains resistance in oxidizing media. One material therefore covers process streams that alternate between oxidizing and reducing conditions.

Jiangyin Jiangnan Metal Co., Ltd. forges NiCr23Mo16Cu into seamless rolled rings, flanges, round bars, discs, sleeves, bushings, shafts, tube sheets and near-net machined blanks. All parts are supplied solution annealed at 1149 °C, ultrasonically tested to ASTM A388, and certified to EN 10204 3.1 or 3.2. Forging, heat treatment and rough machining are carried out in our own plant in Jiangyin, Jiangsu, and each part is traceable to its heat number.

ASTM B564 / B462 DIN 17744 NACE MR0175 EN 10204 3.1 / 3.2

Chemical composition

Limits per ASTM B564 and ASTM B574 for UNS N06200, with the nominal aim chemistry.

Composition limits: ASTM B564 and ASTM B574 for UNS N06200, DIN 17744 for 2.4675. Nominal values: Haynes International C-2000 datasheet H-2118C. Our melt route is EAF plus AOD or VOD followed by ESR remelting. Ladle and product analysis are both reported on the mill certificate.

Mechanical properties

Minimum values are the acceptance criteria of the specification. Typical values are those measured on solution annealed forged bar.

Minima: ASTM B564, UNS N06200, solution annealed. Typical values: Haynes International datasheet H-2118C, 25.4 mm annealed bar. Impact testing is not required by ASTM B564 and can be added as a supplementary requirement.

The row at 427 °C (800 °F) is the ASME Section VIII Division 1, B16.5 and B16.34 design temperature limit for N06200. VdTUV Werkstoffblatt 539 permits 450 °C. Source: Haynes International H-2118C.

Physical properties

Source: Haynes International C-2000 alloy datasheet H-2118C. Thermal conductivity is low and the expansion coefficient relatively high. Both should be allowed for when setting machining parameters and shrink fit interferences.

Corrosion performance

Localized corrosion resistance is the usual reason for selecting NiCr23Mo16Cu over a lower cost Ni-Cr-Mo grade. Two ASTM G48 values are relevant: the critical pitting temperature and the critical crevice temperature, both measured in acidified 6 % ferric chloride.

Source: Haynes International H-2118C. The critical crevice temperature is 25 °C higher than that of C-276. Crevice conditions occur at gasket faces, under deposits and in flange seats. In seawater crevice testing at LaQue Laboratories over 180 days, C-2000 showed no attacked sites in either quiescent or flowing seawater.

Resistance by medium

• Sulfuric acid. Corrosion rates below 0.1 mm/y across a wide concentration band at moderate temperature. This is the principal reason for selecting the grade over C-276.
• Hydrochloric acid. Good resistance at concentrations up to approximately 10 % at moderate temperature.
• Hydrofluoric, phosphoric, nitric and formic acids. Usable across defined ranges. Check the iso-corrosion data against the actual concentration and temperature.
• Chloride stress corrosion cracking. No cracking in 1008 hours of boiling 45 % MgCl₂ to ASTM G36. 316L cracks in approximately two hours under the same test.
• Mixed streams. One alloy covers both oxidizing and reducing conditions, which removes the need to specify two materials for a single circuit.

Published iso-corrosion data is generated in reagent grade laboratory acids. Process streams contain contaminants that can raise or lower corrosion rates. Coupon testing in the actual medium is recommended before committing to a large forging.

NiCr23Mo16Cu compared with adjacent grades

Composition figures are nominal weight %. We forge every grade listed. See nickel alloy forgings for the full index.

Forged forms produced in NiCr23Mo16Cu

Open-die forged and ring rolled to drawing. Sizes below are our normal working range. Send the drawing for confirmation.

• Seamless rolled ringsOD 200 to 3000 mm, wall 30 to 400 mm
• Forged ringsOD to 3000 mm, height to 800 mm
• Forged flangesWN, SO, BL, LJ, SW, to 60 in.
• Round barsDia. 40 to 800 mm, length to 6000 mm
• Discs and blanksDia. to 2500 mm, thickness to 600 mm
• Tube sheetsDia. to 2500 mm, drilled on request
• Sleeves and bushingsOD to 1500 mm, bored
• Shafts and spindlesDia. to 700 mm, stepped, to 6000 mm
• Hollow barsTrepanned or bored
• Valve bodies and stemsBall, gate, globe, check, plug
• Nozzles and forged blocksTo drawing
• Near-net machined partsRough or finish machined in house

Single piece weight from a few kilograms to several tonnes. NiCr23Mo16Cu billet is high cost, so near-net shapes are quoted wherever the geometry allows. The material saved usually exceeds the additional forging cost.

Production route

1. Melting: EAF plus AOD or VOD, then ESRElectric arc melting, argon oxygen or vacuum oxygen decarburisation to bring carbon below 0.010 %, then electroslag remelting for a clean ingot with low segregation. Low carbon and low silicon are what keep the alloy free of grain boundary precipitates.
2. Ingot conditioning and heatingSurface conditioned, then soaked to 1232 °C. Uniform through heating is critical. An unevenly heated ingot will crack during the first reduction.
3. Open-die forging, 1232 to 954 °CUpsetting and drawing in moderate reductions with reheats between passes. Forging ratio is set to break down the cast structure and produce grain flow following the part contour.
4. Ring rolling for ring partsPierced and rolled on a radial-axial mill to produce a seamless rolled ring. Circumferential grain flow gives higher properties than a ring machined from plate.
5. Solution annealing, 1149 °C and water quenchHeld 10 to 30 minutes at temperature according to section thickness, then quenched. This returns secondary phases to solution and restores corrosion resistance and ductility after hot work. Furnace charts are included in the certificate.
6. Descaling and rough machiningPickled or blasted, then turned or bored to the dimensions specified. Nickel alloys work harden rapidly, so machining uses positive rake tooling, rigid setups and a constant heavy feed.
7. Testing and inspectionChemical analysis, tensile and elongation, hardness, ultrasonic testing, dimensional check and positive material identification. Details in the following section.
8. Certification and dispatchEN 10204 3.1 or 3.2 documentation, hard stamped heat number, marked and packed for sea or air freight.

Testing, inspection and certification

Certification is issued to EN 10204 3.1 as standard, or EN 10204 3.2 with third party witness on request. Magnetic particle inspection does not apply, since NiCr23Mo16Cu is non-magnetic. Liquid penetrant is used for surface examination.

Applications

Chemical and petrochemical processing

Reactor shells and heads, heat exchanger tube sheets and channel covers, forged flanges and nozzles for columns and towers, pump casings and impeller hubs, valve bodies and seat rings. Principal applications are sulfuric acid plants, mixed acid units and services where the stream alternates between oxidizing and reducing conditions.

Oil, gas and offshore

Wellhead and Christmas tree components, subsea and deepwater production hardware, forged blocks and manifold bodies, valve stems and bonnets. UNS N06200 is listed in NACE MR0175 / ISO 15156 for sour service. Confirm the hardness limits on the applicable material data sheet at enquiry stage.

Flue gas desulfurisation and pollution control

Absorber internals, forged flanges and nozzles, agitator shafts and sleeves. Low pH chloride scrubber liquor is a crevice corrosion duty, where the 80 °C critical crevice temperature is the relevant property.

Pharmaceutical, fine chemicals and biochemistry

Crystalliser components, agitator shafts, forged sleeves and bushings, sanitary process fittings. Product purity and freedom from iron contamination are often as important as corrosion rate in these applications.

Marine, desalination and power

Seawater wetted flanges and sleeves, brine heater components, condenser tube sheets, pump and valve parts. The seawater crevice test result, no attacked sites over 180 days in still and flowing seawater, supports selection over 625 or 254 SMO in crevice prone geometry.

Pulp, paper and mineral processing

Digester and bleach plant hardware, forged rolls and roll journals, plunger and chemical pump shafts, wear sleeves.

Information required for a quotation

Quotation accuracy depends on material utilisation. The following information allows a firm price:

1. Drawing or dimensions. PDF or DWG. Rough dimensions with a sketch are sufficient for a budget figure.
2. Product form and quantity. Ring, flange, bar, disc or shaft, quantity, and whether repeat orders are expected.
3. Governing specification. ASTM B564, ASTM B462, DIN 17744 or a client specification. State whether a code case applies, such as ASME VIII-1 or NACE MR0175.
4. Supply condition. As forged, solution annealed, rough machined or finish machined to drawing.
5. Testing and certification. EN 10204 3.1 or 3.2, and any additional NDT, ASTM G28 or impact testing required.
6. Destination port and required delivery date.

Quotations are normally returned within 24 hours on working days. Send enquiries to sales@steelforgepieces.com or contact +86-189-2135-9659 by WhatsApp or WeChat.

Frequently asked questions

Related nickel alloy grades

• Hastelloy C-2000
• Hastelloy C-276
• Hastelloy C-22
• Hastelloy C-4
• Hastelloy B-2
• Hastelloy B-3
• Hastelloy B-4
• Hastelloy G-3
• Hastelloy X
• Alloy 59
• Alloy 602
• Inconel 625
• Inconel 600
• Inconel 601
• Inconel 617
• Inconel 690
• Inconel 693
• Inconel 725
• Inconel X-750
• Incoloy 800
• Incoloy 800H
• Incoloy 800HT
• Incoloy 825
• Incoloy 890
• Incoloy 901
• Incoloy 925
• Incoloy 926
• Incoloy 945

Data sources

Property data on this page is taken from the following published sources.

• Haynes International, HASTELLOY C-2000 alloy, Principal Features, document H-2118C. Nominal composition, physical properties, tensile and impact data, corrosion test results, hot working and annealing temperatures.
• ASTM B564, Standard Specification for Nickel Alloy Forgings. Composition and mechanical property minima for UNS N06200 forgings.
• ASTM B462, Standard Specification for Forged or Rolled Nickel Alloy Pipe Flanges, Forged Fittings, Valves and Parts.
• ASTM B574, Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum Alloy Rod and Bar.
• DIN 17744 and VdTUV Werkstoffblatt 539. European designation and approval.
• ASTM G48 pitting and crevice testing, ASTM G36 stress corrosion cracking, ASTM A388 ultrasonic testing, ASTM G28 intergranular corrosion, EN 10204 certification.
• D. M. Aylor et al., Paper No. 329, CORROSION 99, NACE International. Seawater crevice corrosion data from LaQue Laboratories.

Page last reviewed 24 August 2026 by the technical sales department, Jiangyin Jiangnan Metal Co., Ltd.