UNS C72200 Tubesheets, Baffles and Open-Die Forgings to ASTM B171
Datasheet and supply range for UNS C72200 chromium-bearing copper-nickel (CuNi16Cr), forged and machined by Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China.
UNS C72200 key data
- UNS number
- C72200
- Common description
- Chromium-bearing copper-nickel, CuNi16Cr
- Nominal chemistry
- Cu balance, 16 % Ni, 0.5 % Cr, 0.8 % Fe, 0.5 % Mn
- Governing standards
- ASTM B171/B171M (plate), ASTM B111/B111M (condenser tube), ASTM B122/B122M (plate, sheet, strip, rolled bar), ASME SB-171 and SB-111
- Density
- 8.94 g/cm³ (0.323 lb/in³)
- Tensile strength, annealed
- 315 MPa (45,700 psi), 46 % elongation
- Thermal conductivity
- 34.5 W/m·K at 20 °C
- Main use
- Seawater condenser and heat-exchanger tubesheets, baffles and tube in higher-velocity service
- Product forms supplied
- Tubesheets, baffles, support plates, forged discs, seamless rolled rings, flanges, hollow bars, sleeves, bushings, round bars, clad and weld-overlay tubesheets
- Manufacturer
- Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Tel +86-189-2135-9659, email sales@steelforgepieces.com
What is UNS C72200?
UNS C72200 is a wrought copper-nickel alloy containing chromium. Nominal content is 16 % nickel and 0.5 % chromium, with copper as the balance. It belongs to the same alloy family as 90/10 copper-nickel (C70600) and 70/30 copper-nickel (C71500). The chromium addition changes the behaviour of the protective surface film in flowing seawater.
90/10 copper-nickel is low in cost and easy to fabricate, but its surface film breaks down under high flow velocity, entrained sand and turbulence at tube inlets. This failure mode is called erosion-corrosion. 70/30 copper-nickel resists it by carrying more nickel, which raises alloy cost. C72200 holds nickel near 16 % and adds chromium instead, which gives a more stable surface film without the higher nickel content. Condenser tube datasheets describe C72200 as a lower-cost alternative to titanium and to C71640, and report higher heat transfer than titanium, C71500 and C71640.
C72200 is classified as a copper alloy rather than a nickel alloy or a steel, so it is ordered against copper-alloy ASTM specifications. For plate used in pressure vessels, condensers and heat exchangers this is ASTM B171/B171M, which is the source specification for tubesheet material.
Chemical composition of UNS C72200
The table below lists the nominal chemistry quoted on alloy datasheets together with the composition limits permitted by the copper-alloy specifications. Acceptance is against the specification limits, not the nominal figures.
| Element | Nominal (%) | Specification limit (%) | Function |
|---|---|---|---|
| Copper (Cu) | 82.0 | Balance, approx. 78.1 to 84.2 | Base metal, gives thermal conductivity and biofouling resistance |
| Nickel (Ni) | 16.0 | 15.0 to 18.0 | Raises strength and general seawater corrosion resistance |
| Chromium (Cr) | 0.5 | 0.30 to 0.70 | Stabilises the surface film against erosion-corrosion at high velocity |
| Iron (Fe) | 0.8 | 0.50 to 1.00 | Works with chromium to improve impingement resistance |
| Manganese (Mn) | 0.5 | 1.00 max | Deoxidiser, controls sulphur during melting |
| Zinc (Zn) | n/a | 1.00 max | Residual limit |
| Lead (Pb) | n/a | 0.05 max | Residual limit, restricted for weldability |
| Other named elements, total | n/a | 0.20 max | Residual limit |
Ordering note. Composition limits differ slightly between ASTM B171, B111 and B122, and between editions of each. State the specification, the edition year and any supplementary requirements on the enquiry, and the certificate will be issued against that document.
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.94 g/cm³ | 0.323 lb/in³ |
| Melting onset (solidus) | approx. 1120 °C | approx. 2050 °F |
| Melting completion (liquidus) | approx. 1180 °C | approx. 2150 °F |
| Electrical conductivity | approx. 6.5 % IACS | |
| Magnetic response | Non-magnetic in the annealed condition | |
Mechanical properties
The values below are typical for the two tempers most often quoted for C72200. Annealed O61 is the condition normally used for tubesheets and formed components. Full-hard H04 shows the effect of cold work.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, annealed (O61) | 315 MPa | 45,700 psi |
| Tensile strength, full hard (H04) | 480 MPa | 69,600 psi |
| Yield strength 0.2 %, annealed (O61) | 125 MPa | 18,100 psi |
| Yield strength 0.2 %, full hard (H04) | 455 MPa | 66,000 psi |
| Elongation at break, annealed (O61) | 46 % | 46 % |
| Elongation at break, full hard (H04) | 6 % | 6 % |
| Elastic (Young's) modulus | 117 GPa | 17,000 ksi |
| Shear modulus | 55.0 GPa | 7,980 ksi |
| Poisson's ratio | 0.34 | 0.34 |
| Hardness, across tempers | approx. HRB 71 to 86 | |
Temper designations for plate. ASTM B171/B171M supplies plate as hot rolled or hot rolled and annealed, using temper designations such as M20, M10, O20 and O25. Material for ASME Boiler and Pressure Vessel Code work must be certified in the hot-rolled-and-annealed temper. The O61 and H04 figures above are taken from general wrought-alloy datasheets and are given for design comparison, not as B171 acceptance values.
Thermal properties
| Property | Metric | Imperial |
|---|---|---|
| Thermal conductivity at 20 °C | 34.5 W/m·K | 239 BTU·in/hr·ft²·°F |
| Coefficient of thermal expansion, 20 to 300 °C | 15.8 µm/m·°C | 8.78 µin/in·°F |
| Specific heat capacity | approx. 400 J/kg·K | approx. 0.095 BTU/lb·°F |
| Latent heat of fusion | approx. 220 J/g | n/a |
Thermal conductivity is a direct factor in tubesheet and tube selection. It is one reason copper-nickels stay in condenser service where titanium or stainless steel might otherwise be chosen on corrosion resistance alone.
Heat treatment, forming and welding
Annealing
C72200 is annealed between 732 °C and 816 °C (1350 to 1500 °F). Annealing restores ductility after heavy cold work and delivers the temper required for ASME pressure-vessel service.
Hot and cold working
The alloy hot works readily, which makes open-die forging of thick tubesheet blanks, discs and rings practical. It work-hardens during cold forming, so intermediate anneals are scheduled between heavy cold passes. The chromium addition allows certain strengthening heat treatments, so the achievable property range is wider than for plain copper-nickels.
Welding
C72200 is welded by GTAW, GMAW and SMAW. Copper-nickel consumables of the 70/30 type are normally used: AWS A5.7 ERCuNi for bare wire and AWS A5.6 ECuNi for covered electrodes. Preheat is not normally required. Interpass temperature is kept low, joint faces are cleaned back to bright metal, and sulphur-bearing contaminants such as cutting oils and marking crayons are kept off the weld area. The procedure and the welders should be qualified to the governing construction code, ASME Section IX or equivalent.
Machining
Copper-nickels cut gummy compared with steel. Tubesheet drilling uses sharp tooling, positive rake, generous coolant and controlled feeds to hold hole tolerance and surface finish across hundreds of holes without work-hardening the bore.
Corrosion performance in seawater
Copper-nickel alloys are specified for marine service for two reasons. Barnacles and mussels do not settle readily on a copper-rich surface, which lowers chlorination demand, and the protective film re-forms in aerated seawater.
C72200 adds resistance to erosion-corrosion. In a condenser the highest risk locations are tube inlets, tubesheet faces and any point where flow accelerates or carries solids. Chromium and iron together strengthen the protective film so that it survives higher shear at the metal surface. This is why C72200 is selected where 90/10 C70600 would be velocity limited.
Review the following with the end user before specifying the alloy:
- Design and upset flow velocities, including tube-inlet turbulence
- Sand or silt loading in the cooling water
- Sulphide contamination, since polluted or stagnant water degrades the film on all copper alloys
- Chlorination regime and residual chlorine level
- Galvanic pairing with tubes, cladding, fasteners and water-box coatings
- Maximum metal temperature, since the mechanical service ceiling is modest compared with nickel alloys
Not a substitute for a corrosion assessment. The notes above are general guidance. Velocity limits, temperature limits and material compatibility must be confirmed against the project specification and the water analysis by the responsible engineer.
C72200 compared with C70600, C71500 and titanium
| Criterion | C70600 (90/10 Cu-Ni) | C72200 (CuNi16Cr) | C71500 (70/30 Cu-Ni) | Titanium Gr. 2 |
|---|---|---|---|---|
| Nominal Ni content | 10 % | 16 % plus 0.5 % Cr | 30 % | n/a |
| Erosion-corrosion resistance | Moderate | High | High | Very high |
| Thermal conductivity | Highest of the Cu-Ni group | 34.5 W/m·K | Lower than C72200 | Lowest of the four |
| Biofouling resistance | Inherent | Inherent | Inherent | None, requires chlorination |
| Relative alloy cost | Lowest | Low to medium | Medium | Highest |
| Typical reason to select it | Clean, moderate-velocity seawater | Higher velocity without 30 % nickel or titanium cost | Aggressive water, established specification | Severe or polluted service, high chloride |
UNS C72200 products we forge and machine
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory. For C72200 we supply finished and semi-finished components rather than mill stock.
Heat-exchanger and condenser components
- Tubesheets and tube plates: fixed, stationary and floating heads, drilled and grooved to drawing
- Baffles and support plates: single-segmental, double-segmental and disc-and-doughnut patterns
- Clad and weld-overlay tubesheets: a C72200 layer explosion bonded, roll bonded or weld overlaid onto a carbon or low-alloy steel backing, used where a solid copper-nickel tubesheet is not economic
Open-die and rolled-ring forgings
- Forged discs, blanks and blind blanks
- Seamless rolled rings and forged rings
- Forged flanges and hubs
- Sleeves, bushings, housings, shells and cylinders
- Round bars, hollow bars and trepanned bars
| Item | Outside diameter | Thickness or length | Unit weight |
|---|---|---|---|
| Tubesheets and tube plates | up to 4,000 mm | up to 400 mm thick | up to 15 t |
| Baffles and support plates | up to 4,000 mm | 6 to 120 mm thick | n/a |
| Seamless rolled rings | 200 to 3,500 mm | up to 1,000 mm height | up to 10 t |
| Forged discs and blanks | 100 to 2,500 mm | up to 600 mm thick | up to 12 t |
| Round and hollow bars | 60 to 1,200 mm | up to 6,000 mm long | n/a |
Supply condition is normally annealed, rough machined with machining allowance, or finish machined to drawing. Shot blasting, marking, hard stamping, preservation and seaworthy packing are included as standard.
Quality control, testing and certification
- Chemical analysis: optical emission spectrometry on each heat, with positive material identification (PMI) on finished parts
- Mechanical testing: tensile, yield and elongation to ASTM E8/E8M, hardness to ASTM E18
- Non-destructive examination: ultrasonic testing, liquid-penetrant examination and visual inspection to the acceptance class stated on the order
- Dimensional report: CMM or manual report covering diameter, thickness, flatness, hole pitch and hole diameter for drilled tubesheets
- Certification: mill test certificate to EN 10204 3.1, or 3.2 endorsed by SGS, BV, TÜV, Lloyd's Register, DNV or the end user inspector
- Traceability: heat number and job number stamped and recorded through every operation
What to send us for a quotation
A firm price and lead time normally comes back within one working day if the enquiry includes:
- Grade and specification with edition year, for example UNS C72200 to ASTM B171/B171M-24
- Drawing in PDF or DWG, or finished dimensions with machining allowance
- For tubesheets, hole count, hole diameter and tolerance, pitch, pattern and groove detail
- Required temper and supply condition
- Test scope and certificate level, 3.1 or 3.2, and which inspection body
- Quantity and required delivery port or Incoterm
Frequently asked questions about UNS C72200
What is UNS C72200?
UNS C72200 is a wrought copper-nickel alloy containing chromium. Nominal content is 16 % nickel and 0.5 % chromium, with copper as the balance. The chromium raises resistance to erosion-corrosion in flowing seawater, so C72200 can be used at higher design velocities than 90/10 copper-nickel (C70600) without moving to 70/30 copper-nickel (C71500) or titanium.
Which standards cover UNS C72200?
Plate, sheet and circles cut from plate are covered by ASTM B171/B171M, which lists C72200 among its alloys and is adopted by ASME as SB-171. Seamless condenser tube is covered by ASTM B111/B111M, adopted as ASME SB-111. Plate, sheet, strip and rolled bar are also covered by ASTM B122/B122M. Order against the edition named in the project specification.
What is the chemical composition of C72200?
Typical composition limits are nickel 15.0 to 18.0 %, chromium 0.30 to 0.70 %, iron 0.50 to 1.00 %, manganese 1.0 % max, zinc 1.0 % max and lead 0.05 % max, with copper as the balance at roughly 78 to 84 %. Nominal chemistry is Cu-16Ni-0.5Cr-0.8Fe-0.5Mn.
How strong is C72200?
In the annealed O61 condition, typical tensile strength is 315 MPa (45,700 psi), with 0.2 % yield strength of 125 MPa (18,100 psi) and about 46 % elongation. Cold worked to full-hard H04, typical tensile strength is 480 MPa (69,600 psi), with 455 MPa (66,000 psi) yield and about 6 % elongation. Plate ordered to ASTM B171 is supplied in hot-rolled or hot-rolled-and-annealed tempers, and ASME pressure-vessel work requires the annealed temper.
Is C72200 better than C70600 or C71500 for seawater service?
C72200 sits between them. The chromium content gives better erosion-corrosion resistance than 90/10 C70600 at raised flow velocities, while nickel content and cost stay below 70/30 C71500. Condenser tube datasheets also describe C72200 as a lower-cost alternative to titanium and to C71640. The correct choice depends on design velocity, water chemistry, temperature and the end user specification.
Can C72200 be welded?
Yes. C72200 is welded by GTAW, GMAW or SMAW using copper-nickel consumables of the 70/30 type, normally AWS A5.7 ERCuNi for bare wire and AWS A5.6 ECuNi for covered electrodes. Preheat is not normally required. Interpass temperature is kept low, joint faces are cleaned to bright metal, and sulphur-bearing contaminants are excluded. The procedure should be qualified to the governing construction code.
What is the annealing temperature for C72200?
C72200 is normally annealed between 732 °C and 816 °C (1350 to 1500 °F), followed by a suitable cool. The alloy work-hardens during cold forming, so intermediate anneals are used between heavy cold-working passes.
What product forms of C72200 does Jiangyin Jiangnan Metal supply?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin, Jiangsu, China, supplies C72200 as heat-exchanger tubesheets in fixed, stationary and floating configurations, baffles, support plates and tube plates, forged discs and blanks, seamless rolled rings, flanges, hollow bars, sleeves, bushings and round bars, together with clad and weld-overlay tubesheets carrying a C72200 layer on a carbon or low-alloy steel backing. Contact sales@steelforgepieces.com or +86-189-2135-9659.
What certificates are issued with C72200 forgings?
Material is supplied with a mill test certificate to EN 10204 3.1, or 3.2 with third-party endorsement by SGS, BV, TÜV, Lloyd's Register or the end user inspector. Typical test scope covers chemical analysis, tensile and elongation, hardness, ultrasonic or liquid-penetrant examination, a dimensional report and positive material identification.
What information is needed to quote a C72200 tubesheet?
Send the grade and specification edition, finished outside diameter and thickness, machining allowance or finished drawing, drilling pattern including hole count, pitch and tolerance, required temper and test scope, certificate level, quantity and delivery port. A drawing in PDF or DWG is enough to return a firm price and lead time.
Request a quotation for UNS C72200
Send a drawing or a specification and we will come back with price, lead time and the test plan.
Email sales@steelforgepieces.com Call +86-189-2135-9659
Jiangyin Jiangnan Metal Co., Ltd.
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
About Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We produce tubesheets, baffles, forged discs, seamless rolled rings, flanges, sleeves, shafts and bars in carbon steel, alloy steel, tool steel, stainless steel, nickel alloys and copper-nickel alloys including UNS C72200, and supply heat-exchanger, pressure-vessel, marine, power and petrochemical fabricators worldwide.
Enquiries: sales@steelforgepieces.com or +86-189-2135-9659
References
- ASTM B171/B171M, Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers. C72200 is one of the alloys covered.
- ASTM B111/B111M, Standard Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock
- ASTM B122/B122M, Standard Specification for Copper-Nickel-Tin Alloy, Copper-Nickel-Zinc Alloy (Nickel Silver), and Copper-Nickel Alloy Plate, Sheet, Strip, and Rolled Bar
- ASTM E8/E8M, tension testing, and ASTM E18, Rockwell hardness
- ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (ed.), ASM International
- Published wrought copper-nickel alloy datasheets for UNS C72200