C36500 Tube Sheets, Baffles and Forgings to ASTM B171
UNS C36500 | CDA 365 | CuZn39Pb0,5 (CW610N) | CZ137. Leaded Muntz metal manufactured to ASTM B171/B171M and ASME SB-171 by Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China.
Short answer
UNS C36500 is leaded Muntz metal, uninhibited. It is an alpha-beta 60/40 brass of 58.0-61.0% copper, 0.25-0.7% lead, 0.25% tin max, 0.15% iron max, balance zinc. Under ASTM B171 it is the standard tube-sheet brass for condensers and heat exchangers, with a minimum 345 MPa (50 ksi) tensile strength and 35% elongation up to 50 mm thick, at a density of 8.41 g/cm³. Jiangyin Jiangnan Metal Co., Ltd. forges, rolls, drills and certifies C36500 tube sheets, baffles and support plates to order.
- UNS / CDA
- C36500 / 365
- Alloy family
- Leaded brass (Cu-Zn-Pb)
- Standard
- ASTM B171 / SB-171
- Density
- 8.41 g/cm³
- Tensile, min
- 345 MPa / 50 ksi
- Elongation, min
- 35%
- Machinability
- 60% of C36000
- Inhibited
- No, uninhibited
1. What C36500 is
C36500 is the UNS number for leaded Muntz metal in the uninhibited condition. The Copper Development Association classifies it under wrought copper-zinc-lead alloys, the leaded brasses. It is a two-phase alpha-beta 60/40 brass. The beta phase makes it easy to hot forge and hot roll, and the 0.25-0.7% lead addition breaks up the chip, so the thousands of tube holes in a tube sheet can be drilled at sensible cost.
The alloy is listed in ASTM B171/B171M, Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers, together with C44300, C44400, C44500, C46400, C46500, C61300, C61400, C63000, C63200, C70600, C70620, C71500, C71520 and C72200. Within that group C36500 is the low-cost, highly machinable choice for fresh-water and moderate-duty condenser tube plates. It is not the alloy for severe seawater service, as section 8 explains.
A common mix-up. C36500 is not a nickel aluminium bronze. Data sheets showing roughly 9-11% aluminium and 4-5.5% nickel belong to UNS C63000, a separate alloy that appears in the same ASTM B171 standard. If a supplier quotes C36500 but the certificate shows aluminium and nickel, the material does not match your drawing. Match the UNS number on the mill certificate, not the trade name.
2. C36500 products we manufacture
Jiangyin Jiangnan Metal Co., Ltd. produces C36500 as forged and hot-rolled product, machined to the customer drawing rather than sold as stock plate.
| Product form | Specification | Typical duty |
|---|---|---|
| Tube sheets, tubesheets and tube plates, drilled and grooved | ASTM B171 / ASME SB-171 | Shell-and-tube condensers, coolers, feedwater heaters |
| Baffles, support plates, tie rods and spacers | ASTM B171 | Tube-bundle support and flow direction |
| Front, rear, stationary and floating head tube sheets | ASTM B171 with TEMA | Fixed, U-tube and floating-head exchangers |
| Forged discs, blanks and circles | ASTM B124 / B283 | Blanks for machined tube sheets and covers |
| Seamless rolled rings and forged flanges | ASTM B124/B124M | Heat exchanger headers, channel flanges |
| Round bars, hollow bars, sleeves and bushes | ASTM B124/B124M | Valve stems, bushings, machined parts |
| Clad and weld-overlaid tube sheets on steel backing | ASTM B432 (clad plate) | Cost-reduced large-diameter tube sheets |
Plant capability. Tube sheets up to 4,000 mm diameter and 10-350 mm thick. Single-piece forged weight to 15 t. CNC tube-hole drilling to TEMA R, C and B tolerances. Typical lead time 25-40 days after drawing approval. Send a drawing to sales@steelforgepieces.com for confirmation against current shop loading.
3. Chemical composition of C36500
The composition limits below are those of ASTM B171/B171M Table 1, in weight percent. C36500 carries no arsenic, antimony or phosphorus addition, and that absence is what uninhibited means.
| Element | Minimum | Maximum | Function in the alloy |
|---|---|---|---|
| Copper (incl. silver) | 58.0 | 61.0 | Base metal, sets the alpha and beta balance |
| Lead (Pb) | 0.25 | 0.7 | Chip breaker, the reason tube holes drill cleanly |
| Tin (Sn) | n/a | 0.25 | Residual, mild corrosion benefit |
| Iron (Fe) | n/a | 0.15 | Residual limit |
| Zinc (Zn) | Remainder, nominally about 40% | Strength and hot workability through the beta phase | |
Copper plus the sum of the named elements must be 99.6% minimum. Depending on the analytical method, either copper or zinc may be reported as the difference from 100%.
4. Mechanical properties of C36500
ASTM B171 grades the required strength by thickness. This is the table that decides whether a thick tube sheet is acceptable, and it is the one most often quoted wrongly.
| Thickness | Tensile strength, min | Yield at 0.5% extension, min | Yield 0.2% offset, min | Elongation in 50 mm, min |
|---|---|---|---|---|
| Up to 50.0 mm (2 in.) | 345 MPa (50 ksi) | 140 MPa (20 ksi) | 140 MPa (20 ksi) | 35% |
| Over 50.0 to 100.0 mm (2 to 3.5 in.) | 310 MPa (45 ksi) | 105 MPa (15 ksi) | 105 MPa (15 ksi) | 35% |
| Over 100.0 to 140.0 mm (3.5 to 5 in.) | 275 MPa (40 ksi) | 85 MPa (12 ksi) | 85 MPa (12 ksi) | 35% |
| Property | Typical value |
|---|---|
| Tensile strength | 372 MPa (54 ksi) |
| Yield strength at 0.5% extension | 138 MPa (20 ksi) |
| Elongation in 50 mm | 45% |
| Hardness | 80 HRF (Rockwell F) |
| Shear strength | 276 MPa (40 ksi) |
C36500 is hardenable by cold work only. It has no response to heat treatment, so there is no quench-and-temper route to higher strength.
5. Physical properties of C36500
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.41 g/cm³ | 0.304 lb/in³ |
| Melting range, solidus to liquidus | 888 to 899 °C | 1630 to 1650 °F |
| Thermal conductivity | about 123 W/m·K | 71 Btu·ft/(hr·ft²·°F) |
| Coefficient of thermal expansion | 20.9 x 10-6 /°C (20 to 300 °C) | 11.6 x 10-6 /°F (68 to 572 °F) |
| Electrical conductivity | 28% IACS | |
| Specific heat capacity | about 377 J/kg·K | 0.09 Btu/lb·°F |
| Modulus of elasticity in tension | about 103 GPa | 15,000 ksi |
| Modulus of rigidity | about 39 GPa | 5,600 ksi |
| Machinability rating | 60, where free-cutting brass C36000 is 100 | |
Quick weight check: a 2,000 mm diameter by 60 mm thick C36500 tube sheet blank weighs about 1,585 kg before tube holes are drilled, from pi x 1.0² x 0.06 m³ x 8,410 kg/m³.
6. Tempers, annealing and hot working
| Item | Value or designation |
|---|---|
| Tempers in B171 | As hot rolled (M20), hot rolled and annealed (O25), hot forged and annealed (O20), as hot forged air cooled (M10) |
| ASME B&PV Code work | Must be certified in the hot rolled and annealed temper |
| Annealing temperature | 427 to 593 °C (800 to 1100 °F) |
| Hot working temperature | 621 to 788 °C (1150 to 1450 °F) |
| Capacity for hot forming | Excellent, which is why C36500 suits open-die forging |
| Capacity for cold working | Fair, so heavy cold reduction is not the route to size |
7. Machining, joining and forming
Machining and tube-hole drilling
With a machinability rating of 60 against free-cutting brass, C36500 drills and bores far more easily than the copper-nickels or the aluminium bronzes in ASTM B171. On a tube sheet with several thousand holes that difference drives the cost, which is why the alloy is still specified today. Use sharp brass-ground tooling with zero or negative rake, generous through-coolant, and peck cycles to clear the short chips that the lead produces.
Joining
| Process | Rating | Practical note |
|---|---|---|
| Soldering | Excellent | Preferred route for small joints |
| Brazing | Good | Control heat input to limit zinc loss |
| Gas-shielded arc welding | Fair | Qualify the procedure, expect zinc fume |
| Oxyacetylene welding | Fair | Flux and a reducing flame |
| Coated metal arc welding | Not recommended | n/a |
| Spot and seam welding | Not recommended | n/a |
Health and safety. C36500 contains both lead and roughly 40% zinc. Welding, brazing and hot grinding release zinc oxide and lead fume, so use local exhaust ventilation and follow your national occupational exposure limits. Tube-to-tube-sheet joints in this alloy are normally expanded by rolling rather than welded.
8. Corrosion behaviour and dezincification
C36500 gives good service in fresh water, in many condenser and cooler duties, and in mildly corrosive process water. Its published strength and general corrosion resistance are comparable to C46400 naval brass, and its higher lead content gives noticeably better machinability.
The limitation is selective leaching. In a duplex brass with about 40% zinc the beta phase can dezincify: zinc leaves preferentially and a porous, weak copper residue is left behind, most readily in stagnant, hot, chlorinated or brackish water. C36500 is the uninhibited grade, so it carries no arsenic, antimony or phosphorus addition to suppress that mechanism.
| UNS | Name | Inhibitor | Status |
|---|---|---|---|
| C36500 | Leaded Muntz metal, uninhibited | None | Active, the alloy listed in current ASTM B171 |
| C36600 | Leaded Muntz metal, arsenical | As 0.02 to 0.06% | Inactive CDA designation |
| C36700 | Leaded Muntz metal, antimonial | Sb 0.02 to 0.10% | Inactive CDA designation |
| C36800 | Leaded Muntz metal, phosphorized | P 0.02 to 0.10% | Inactive CDA designation |
The inhibited Muntz grades are no longer active designations. A specification calling for inhibited leaded Muntz on a new build is usually satisfied by moving to an inhibited Admiralty brass or a copper-nickel instead. Ask us before you re-specify.
When to choose something else
- C44300 Admiralty brass, arsenical, with As 0.02 to 0.06%, is dezincification-inhibited, for water that is chlorinated, warm or intermittently stagnant.
- C46400 naval brass has similar strength, higher tin and lower lead. Better where machinability matters less than corrosion margin.
- C70600 90-10 copper-nickel is the standard step up for seawater condensers and desalination service.
- C63000 nickel aluminium bronze suits designs driven by strength, at 620 MPa minimum under B171, and by erosion resistance rather than machinability.
9. C36500 equivalents and cross-reference
| System | Designation |
|---|---|
| UNS (USA) | C36500 |
| CDA (USA) | CDA 365 |
| EN numeric | CW610N |
| EN chemical | CuZn39Pb0,5 |
| British Standard, legacy | CZ137 |
| Descriptive | 60/40 leaded Muntz metal, uninhibited |
Do not substitute on an equivalence table alone. Cross-reference tables match chemistry, not test regimes, tempers, tolerances or certification. An order placed to ASTM B171 has to be certified to ASTM B171. We will not ship a CW610N certificate against a B171 purchase order unless your specification allows it.
Where C36500 sits among ASTM B171 alloys
| Alloy | Type | Tensile min at 50 mm and under | Choose it when |
|---|---|---|---|
| C36500 | Leaded Muntz brass | 345 MPa | Fresh water, heavy drilling, cost-driven |
| C44300 | Admiralty brass, arsenical | 310 MPa | Dezincification risk on the water side |
| C46400 | Naval brass | 345 MPa | Marine duty with moderate strength |
| C70600 | 90-10 copper-nickel | 275 MPa | Seawater, desalination, biofouling resistance |
| C71500 | 70-30 copper-nickel | 345 MPa | Higher-velocity seawater |
| C63000 | Nickel aluminium bronze | 620 MPa | High load, erosion and cavitation |
10. Applications of C36500
- Main tube sheets for surface condensers and heat exchangers, the principal use of the alloy
- Condenser tube plates, baffles and support sheets in power station and process cooling trains
- Heat exchanger headers, channel flanges and covers
- Marine and shipbuilding hardware, Muntz metal having started life as hull sheathing
- Valve stems, bushings, sleeves and fasteners machined from forged bar
- Engraving plates, key blanks and architectural work where the warm brass colour is wanted
11. Our plant, process route and quality control
Jiangyin Jiangnan Metal Co., Ltd. operates as an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, inside the Yangtze River Delta metalworking cluster and about two hours from Shanghai port.
Process route for a C36500 tube sheet
- Ingot or billet selection with traceable heat number
- Heating into the 621 to 788 °C hot-working window
- Open-die forging or hot rolling to the blank dimension
- Annealing at 427 to 593 °C where the O25 or O20 temper is ordered
- Rough machining, ultrasonic examination, then finish facing and grooving
- CNC tube-hole drilling to the customer tube layout and pitch
- Dimensional inspection, marking, preservation and export packing
Testing and documentation supplied
- Chemical analysis to ASTM B171 Table 1 by spectrometry, with PMI on request
- Tensile test to ASTM E8/E8M against the applicable thickness band
- Hardness and dimensional reports
- Ultrasonic examination of the forged blank on request
- EN 10204 3.1 mill test certificate as standard, 3.2 with third-party witness from SGS, BV, TUV or Lloyd's on request
- Heat-number traceability from ingot to marked part
12. How to request a C36500 quotation
Send these six items and we will return a firm price and lead time, normally within one working day.
- Alloy and specification, for example ASTM B171 UNS C36500, hot rolled and annealed (O25)
- Outside diameter, or length by width, and thickness
- Quantity and required delivery date
- Tube layout: hole diameter, pitch, pattern, number of holes, tolerance class TEMA R, C or B
- Grooving, cladding or weld-overlay requirements
- Certification and third-party inspection requirements
Request a C36500 quotation
Jiangyin Jiangnan Metal Co., Ltd., Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
13. Frequently asked questions about C36500
What is UNS C36500?
UNS C36500 is leaded Muntz metal, uninhibited. It is an alpha-beta 60/40 brass containing 58.0-61.0% copper, 0.25-0.7% lead, up to 0.25% tin and up to 0.15% iron, with zinc as the balance. It is listed in ASTM B171/B171M for pressure vessel, condenser and heat exchanger plate, and is most often used for tube sheets, tube plates, baffles and support plates.
Is C36500 the same as nickel aluminium bronze?
No. C36500 is a leaded brass of copper, zinc and lead. Nickel aluminium bronze with roughly 9-11% aluminium and 4-5.5% nickel is UNS C63000, a different alloy in the same ASTM B171 standard. The two are often confused because both are supplied as B171 tube sheets. Check the UNS number on the mill certificate, not the trade name.
What is the chemical composition of C36500 to ASTM B171?
ASTM B171 Table 1 specifies copper including silver 58.0-61.0%, lead 0.25-0.7%, tin 0.25% max, iron 0.15% max and zinc as the remainder. Copper plus the named elements must total 99.6% minimum. C36500 contains no deliberate arsenic, antimony or phosphorus inhibitor, and that is why it is called uninhibited.
What are the minimum mechanical properties of C36500 plate?
To ASTM B171 Table 2, plate up to 50 mm thick requires 345 MPa (50 ksi) minimum tensile strength, 140 MPa (20 ksi) minimum yield and 35% minimum elongation in 50 mm. Over 50 to 100 mm the minimums drop to 310 MPa and 105 MPa, and over 100 to 140 mm to 275 MPa and 85 MPa, with 35% elongation throughout.
Is C36500 suitable for seawater service?
C36500 is used in fresh water and in many salt water condensers, but it is the uninhibited grade of leaded Muntz metal, so in aggressive or stagnant brackish water it is vulnerable to dezincification. For those duties specify an inhibited alloy such as C44300 arsenical Admiralty brass, or move to C70600 90-10 copper-nickel. Confirm the service water chemistry with your process engineer.
Which temper is required for ASME Boiler and Pressure Vessel Code work?
ASTM B171 offers as hot rolled (M20), hot rolled and annealed (O25), hot forged and annealed (O20) and as hot forged air-cooled (M10). Material for ASME Boiler and Pressure Vessel Code applications must be certified in the hot rolled and annealed temper. Other work may be supplied as hot rolled or hot rolled and annealed.
Can C36500 be welded?
Only with care. The Copper Development Association rates gas-shielded arc welding and oxyacetylene welding of C36500 as fair, and rates coated metal arc, spot and seam welding as not recommended, because zinc volatilises from the weld pool. Soldering is rated excellent and brazing good, so soldered or brazed joints are usually preferred for this alloy.
What is the density of C36500?
The density of C36500 leaded Muntz metal is 8.41 g/cm3, equal to 0.304 lb/in3, as listed in ASTM B171 Table 7 and in the Copper Development Association alloy database. Use this figure when converting a tube sheet drawing into a shipping weight. A 2,000 mm diameter by 60 mm thick plate weighs roughly 1,585 kg before drilling.
What is the European equivalent of C36500?
The closest European designation is CW610N, chemically named CuZn39Pb0,5, with the older British Standard designation CZ137. These are near equivalents on composition, not identical specifications, so an order placed to ASTM B171 should always be certified to ASTM B171 rather than substituted on the basis of an equivalence table.
Who supplies C36500 tube sheets and forgings?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, supplies ASTM B171 C36500 tube sheets, baffles, support plates, forged discs, rings, flanges and bars worldwide. Enquiries: sales@steelforgepieces.com or +86-189-2135-9659, with drawings or a tube layout for a quotation.
14. Sources and how to cite this page
- ASTM International, B171/B171M Standard Specification for Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers, and Heat Exchangers, Tables 1, 2 and 7. astm.org
- Copper Development Association Inc., alloy database entry for C36500, Leaded Muntz Metal, Uninhibited, covering composition, typical properties, fabrication ratings and applicable specifications. alloys.copper.org
- Copper Development Association Inc., Standard Designations for Wrought Copper Alloys, for C36500, C36600, C36700 and C36800 composition limits and designation status.
- ASTM International, B124/B124M for forging rod, bar and shapes, B283/B283M for die forgings, and B432 for clad steel plate, the other specifications under which C36500 is supplied.
Cite this page as:
Jiangyin Jiangnan Metal Co., Ltd. (2026). "C36500 Tube Sheets, Baffles and Forgings to ASTM B171." Jiangyin, Jiangsu, China. http://www.steelforgepieces.com/Alloy-Steel/UNS-C36500.html