UNS C83600 Gunmetal Flanges Manufacturer & Exporter
C83600 is the classic composition bronze, also called ounce metal or 85-5-5-5, and widely referred to as gunmetal in flange and valve work. It casts well, machines easily and is covered by ASTM B62.
UNS C83600 at a glance
- Leaded red brass / composition bronze: Cu 84–86 %, Sn, Pb and Zn about 5 % each
- ASTM B62: 30 ksi tensile, 14 ksi yield, 20 % elongation minimum
- Machinability rating 84
- Leaded: confirm suitability before specifying for potable water
Material Overview and Designation
Designation and classification
UNS C83600| Item | Detail |
|---|---|
| UNS designation | C83600 |
| Common names | Ounce metal; composition bronze; 85-5-5-5; No. 1 composition; leaded red brass; commonly called gunmetal |
| Alloy family | Cast copper-tin-lead-zinc (leaded red brass) |
| Casting specifications | ASTM B62 (composition bronze or ounce metal castings); also ASTM B584 |
| Nominal composition | 85 Cu - 5 Sn - 5 Pb - 5 Zn |
Chemical Composition
Chemical composition (weight %)
SM-CHEM-C83600| Element | Range, % |
|---|---|
| Copper (Cu) | 84.0 – 86.0 |
| Tin (Sn) | 4.0 – 6.0 |
| Lead (Pb) | 4.0 – 6.0 |
| Zinc (Zn) | 4.0 – 6.0 |
| Nickel, iron, antimony, sulfur, phosphorus, aluminium, silicon | Residual limits per ASTM B62 |
Principal-element ranges, weight %. Residual limits are set in ASTM B62.
Mechanical Properties
Mechanical properties: ksi (MPa)
SM-MECH-C83600| Condition / specification | Tensile, min | Yield, min | Elongation, min % |
|---|---|---|---|
| As-cast — ASTM B62 | 30 (≈205) | 14 (≈95) | 20 |
| Typical reference value (as cast) | ≈37 (≈255) | ≈17 (≈115) | Varies with section |
Values are specification minimums or typical reference data and depend on product form, casting method and condition. Acceptance values are those in the specification and purchase order that apply to your order.
Physical and Fabrication Properties
Physical and fabrication data
SM-PHYS-C83600| Property | Value |
|---|---|
| Machinability rating | 84 (CDA scale, free-cutting brass C36000 = 100) |
| Brinell hardness, typical | ≈50 – 65 (500 kg load) |
Physical and fabrication values are published reference data (CDA / producer data sheets). Machinability: free-cutting brass C36000 = 100.
Corrosion Characteristics and Service
C83600 has good resistance to fresh water, many brackish waters and neutral salt solutions, and has long been used for water, steam and valve service at moderate temperatures and pressures. The lead phase gives pressure-tight castings and easy machining, but it also means the alloy is not chosen for potable-water wetted parts where lead-free requirements apply. Confirm alloy suitability and regional regulations for drinking-water contact.
Oxidizing acids, ammonia-bearing media and sulfides attack copper alloys, and flowing seawater at high velocity is better handled by aluminium bronze or nickel aluminium bronze grades. Galvanic coupling to steel pipework and bolting should be taken into account in the design.
Manufacturing and Machining
With a machinability rating of 84, C83600 can be faced, bored, drilled and tapped at high rates with long tool life. Gasket faces take a good finish, which is why it has been a standard alloy for gunmetal valve and pipe flanges. Sand-cast blanks are the usual stock; the composition is also available as centrifugal and continuous-cast product under other ASTM specifications.
Leaded alloys are generally joined to pipe by brazing or soldering, not fusion welding. Piping specifications that call for welding should name a different alloy.
UNS C83600 Flanges and Applications
C83600 gunmetal flanges are used for gunmetal pipe flanges, valve end flanges, pump connections and water service where leaded bronze is accepted. Common styles are threaded, slip-on and blind; reducing and custom flanges are made to drawing.
Flange types in UNS C83600
SM-FLG-C83600| Flange type | Notes |
|---|---|
| Threaded / Screwed Flanges | Gunmetal threaded flanges for water and valve service |
| Slip-On Flanges | Gunmetal pipe flanges, brazed to pipe |
| Blind Flanges | Test blanks and closures |
| Reducing Flanges | Valve and pump adaptors |
- Valve end flanges and valve-side connections
- Pump connections
- Non-potable water and general industrial service
- Marine auxiliary systems where accepted by specification
Inspection and Documentation
Material is verified against UNS C83600 and ASTM B62, with an MTC where required. Dimensional inspection covers OD, thickness, bore or thread, PCD and hole pattern, and visual examination checks gasket faces for porosity. Pressure testing and other examinations are carried out only when listed on the purchase order.
Applicable Standards
Applicable standards
SM-STD-C83600| Standard | Scope |
|---|---|
| ASTM B62 | Composition bronze or ounce metal castings |
| ASTM B584 | Copper alloy sand castings for general applications |
| ASME B16.24 | Cast copper alloy pipe flanges and flanged fittings, where applicable |
| MSS SP-106 | Cast copper alloy flanges and flanged fittings, where applicable |
| MSS SP-25 | Standard marking system for valves, fittings, flanges and unions |
The edition and specification on your purchase order govern. Listing a standard here does not imply approval or certification to it.
UNS C83600: common questions
Is C83600 the same as gunmetal?
In flange and valve work C83600 is commonly called gunmetal, ounce metal or 85-5-5-5. Historically, gunmetal refers to tin bronzes, and the term is used loosely for this leaded red brass.
Which ASTM specification covers C83600?
ASTM B62 covers composition bronze or ounce metal castings. Minimum properties are 30 ksi (about 205 MPa) tensile, 14 ksi (about 95 MPa) yield and 20 percent elongation.
Is C83600 suitable for potable water?
C83600 contains about 5 percent lead, so it is not used for drinking-water wetted parts under U.S. lead-free requirements. Confirm suitability and local regulations before specifying it for water service.
Related Information
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