Copper Alloy C28500
UNS C28500
C28500 is a duplex (α+β) 60/40 Muntz-metal-type brass supplied mainly in as-manufactured M20, M30 and M40 conditions alongside O60/O61 anneals and H01–H04 cold-worked tempers.
Reference datasheet — C28500 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the M30 condition
C28500 tempers and conditions
C28500 is supplied in 8 conditions, soft to hard. M30 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for maximum ductility when the part still needs some cold bending or upsetting after annealing. | 115 | 355 | 52 | 58 HB | 28 % IACS |
Annealed | General-purpose annealed condition for plate, sheet and rod that will be formed or machined then finished. | 140 | 370 | 48 | 65 HB | 28 % IACS |
M30Default As hot extruded | The usual stocked form: hot-extruded rod/bar sold as forging blanks and hardware stock. | 145 | 380 | 45 | 70 HB | 28 % IACS |
As hot rolled | Standard mill condition for Muntz-type plate used in marine sheathing, tube sheets and heavy hardware. | 150 | 380 | 45 | 72 HB | 28 % IACS |
As hot forged and air cooled | Condition of finished hot forgings (valve bodies, fittings) taken directly from the die with no post-heat treatment. | 155 | 385 | 40 | 75 HB | 28 % IACS |
Quarter hard | Light cold work for better straightness, surface finish and moderate strength in rod and sheet. | 275 | 420 | 28 | 105 HB | 27 % IACS |
Half hard | Choose when higher yield strength and wear resistance are needed and only mild bending is required. | 350 | 470 | 18 | 125 HB | 27 % IACS |
Full hard | Maximum strength condition for straight rod, springs-free hardware and wear surfaces; very little remaining ductility. | 410 | 540 | 10 | 150 HB | 26 % IACS |
What is C28500?
C28500 is a duplex (α+β) 60/40 Muntz-metal-type brass supplied mainly in as-manufactured M20, M30 and M40 conditions alongside O60/O61 anneals and H01–H04 cold-worked tempers. Engineers specify it for hot workability and strength in forged and extruded parts: 145 MPa yield, 380 MPa tensile, 45% elongation and 70 HB in the default condition, with 28% IACS conductivity and service to 200 °C. Cold formability is limited and fusion welding causes zinc fuming and porosity, so severe cold work needs interstage annealing. C28000 Muntz metal is the closest alternative for hot-worked stock. C28500 has a density of 8.39 g/cm³ (0.303 lb/in³), lighter than 76% of copper alloy grades. It melts at 899°C (1,650 °F). C28500 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 105 GPa (15.2 Msi).
What is C28500 used for?
- forging blanks
- hardware
- structural extrusions
Advantages
- Ductile — tolerates forming and impact — 45%, better than 91% of copper alloy grades
- Low embodied carbon — 3.3 kg CO₂/kg, better than 90% of copper alloy grades
Limitations
- Needs corrosion protection — 45/100, worse than 98% of copper alloy grades
C28500 properties
Typical room-temperature values for C28500-M30; bars are the position among copper alloy grades.
Physical3
C28500 has a density of 8.39 g/cm³ (0.303 lb/in³), lighter than 76% of copper alloy grades. It melts at 899°C (1,650 °F).
Mechanical14
C28500 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
C28500 is rated for continuous service to 200°C (392 °F). It conducts heat at 123 W/m·K (71.1 BTU/hr·ft·°F), better than 70% of copper alloy grades. Thermal expansion is 20.8 µm/m·K (11.6 µin/in·°F).
Electrical3
C28500 conducts electricity at 28 % IACS, better than 69% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 98% of copper alloy grades.
Sustainability4
Producing a kilogram of C28500 takes about 55 MJ of energy and emits 3.3 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 50%.
Manufacturability8
C28500's machinability is fair (45/100, better than 64% of copper alloy grades); weldability fair (45/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C28500 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C28500
Is C28500 easy to machine?
Machines like a duplex brass — roughly 40 % of free-cutting C36000: use sharp positive-rake tools, high speed, light feeds and coolant; the β phase chips well but is gummier than leaded brass.
Can C28500 be welded?
Best joined by brazing or soldering; TIG/MIG with silicon-bronze filler is possible but zinc fuming, porosity and dezincified weld zones require extraction and low heat input.
Can C28500 be formed, bent or molded?
Excellent hot working at 620–780 °C (forge, extrude, hot roll); cold formability is limited — anneal at 425–600 °C between severe cold operations and stress-relieve to avoid SCC.
C28500 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cu60/40 Muntz-type range; verify exact limits against the current CDA/ASTM registration for C28500 | 59 – 62 | 60.5 |
| Pbresidual/intentional low lead for hot-working and machining | ≤ 0.3 | 0.1 |
| Fe | ≤ 0.15 | 0.05 |
| Snresidual from scrap | ≤ 0.1 | |
| Alresidual | ≤ 0.05 | |
| Znnominally ~40 % | balance |
What surface finishes work on C28500?
Takes a bright mechanical polish and accepts Ni/Cr or decorative plating; not anodizable — protect with lacquer or chemical bronze/black finishes, and stress-relieve before plating to prevent cracking.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does C28500 cost?
C28500 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C28500 — frequently asked
What is C28500 used for?
C28500 is typically used for forging blanks, hardware and structural extrusions. In short: hot-forgeable duplex brass; high elongation, 45%; strong hot-worked hardware alloy.
What is the yield strength of C28500?
C28500 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C28500 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 64% of copper alloy grades). Machines like a duplex brass — roughly 40 % of free-cutting C36000: use sharp positive-rake tools, high speed, light feeds and coolant; the β phase chips well but is gummier than leaded brass.
Can C28500 be welded?
With care — weldability is rated fair (45/100). Best joined by brazing or soldering; TIG/MIG with silicon-bronze filler is possible but zinc fuming, porosity and dezincified weld zones require extraction and low heat input.
What surface finishes work on C28500?
Takes a bright mechanical polish and accepts Ni/Cr or decorative plating; not anodizable — protect with lacquer or chemical bronze/black finishes, and stress-relieve before plating to prevent cracking.
Can C28500 be formed, bent or molded?
Excellent hot working at 620–780 °C (forge, extrude, hot roll); cold formability is limited — anneal at 425–600 °C between severe cold operations and stress-relieve to avoid SCC.
What is the maximum service temperature of C28500?
C28500 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C28500-M30 and C28500-H04?
M30 is the default condition — the usual stocked form: hot-extruded rod/bar sold as forging blanks and hardware stock. H04: maximum strength condition for straight rod, springs-free hardware and wear surfaces; very little remaining ductility. Yield strength is 145 MPa in M30 versus 410 MPa in H04.
How much does C28500 cost?
C28500 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (Cu–Zn alloys) — ASM International (1990)
- CDA Copper Alloy Database — Muntz metal / 60-40 brass (C28000 family) — Copper Development Association (2023)
- ASTM B124/B124M — Copper and Copper-Alloy Forging Rod, Bar, and Shapes — ASTM (2020)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM (2019)
- ASM Handbook Vol.13 — Corrosion (dezincification, SCC of brasses) — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.