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C27000 / C28000 (Muntz Metal) Brass Sheet metal parts
C27000 / C28000 (Muntz Metal) Brass Sheet Metal Parts
C27000 (UNS C27000, CDA 270, Yellow Brass 65/35, EN CW507L, DIN CuZn35) and C28000 (UNS C28000, CDA 280, Muntz Metal, EN CW508L, DIN CuZn40) are higher-zinc brass alloys used for sheet metal parts, stampings, and formed components where moderate formability, higher strength, and lower material cost are the primary requirements. C27000 (65% Cu, 35% Zn) is a single-phase alpha brass at the upper boundary of alpha-phase composition, while C28000 (60% Cu, 40% Zn) – known as Muntz Metal – is an alpha-beta duplex brass with significantly higher strength and reduced ductility compared to lower-zinc grades. Electrical Accessories India manufactures C27000 and C28000 brass sheet metal parts at our Jamnagar facility, serving electrical hardware, architectural, and industrial sheet metal fabrication customers in India and internationally.
Product Overview
C27000 – Yellow Brass 65/35 – Alloy Profile
C27000 (65/35 Brass) contains 63.0–68.5% copper and 31.5–37% zinc. It is at the upper limit of single-phase alpha-brass composition and may contain trace beta phase at the higher zinc end of the specification range. Tensile strength in the annealed condition is 340–400 MPa with elongation of 45–60%. In half-hard temper, tensile strength reaches 420–480 MPa. The alloy offers a yellow colour, good blanking and bending properties, and is well-suited for flat-blanked sheet metal components, light structural stampings, and formed sheet metal parts not requiring the severe deep-drawing capability of C26000. Electrical conductivity is approximately 24–26% IACS. C27000 represents a cost-effective choice for sheet metal components where material cost is a significant factor and forming severity is limited to blanking, piercing, and moderate bending.
C28000 – Muntz Metal – Alloy Profile
C28000 Muntz Metal (60/40 Brass) contains 59–63% copper and 37–41% zinc, placing it firmly in the alpha-beta two-phase region of the copper-zinc phase diagram. The beta phase (BCC structure) present at higher zinc contents significantly increases strength (tensile strength 370–430 MPa annealed; up to 500 MPa in worked condition) and hardness compared to alpha brasses, but reduces cold-formability and elongation (elongation 25–40% annealed). Muntz Metal has excellent hot-working properties and is readily hot-rolled, hot-extruded, and hot-stamped, making it economical for heavier-gauge sheet metal plate components. Machinability is also good (approximately 40% on the CDA scale) compared to pure alpha brasses. The alloy is susceptible to dezincification in stagnant water or aggressive environments unless inhibited with small arsenic or antimony additions, but performs well in most industrial atmospheric and dry electrical service environments.
Sheet Metal Applications for C27000 and C28000
C27000 and C28000 brass are used for sheet metal parts in a wide range of applications. In electrical and industrial sectors: busbar plates and heavy terminal strips blanked from 2–6 mm plate; panel hardware and structural stampings in 1.5–4 mm sheet; distribution board frame components and mounting plates; earthing plates and grounding bars; cable tray brackets and support hardware. In architectural and general hardware: door kick plates, letter plate blanks, grille panels, and decorative cover sheets from C27000 polished strip; ventilation grille stampings; brass shim stock and spacer plates. Muntz Metal (C28000) is particularly used for heavier gauge plate stampings (2–8 mm), condenser water box sheets (marine and HVAC), and sheet metal components where higher hardness and wear resistance are required alongside the general corrosion resistance of brass.
Comparison – C27000 vs C28000 vs C26000
C26000 (70/30 Cartridge Brass) is the premier deep-drawing alloy with maximum formability – used where severe drawing or complex forming is required. C27000 (65/35 Yellow Brass) offers slightly lower formability but better cost economy and is adequate for most blanking, bending, and light forming stampings. C28000 (60/40 Muntz Metal) is an alpha-beta alloy with higher strength, harder, and lower cold-formability – best suited for heavier gauge sheet metal components, hot-worked parts, and applications where high strength-to-cost ratio matters more than cold-formability. In progressive die stamping operations using thin strip (0.3–2 mm), C27000 is the most practical choice; for thicker plate stampings and machined plate components, C28000 is competitive. Both alloys are more economical than C26000 due to their lower copper content (5–10% less copper by weight).
Technical Specifications
| Property | C27000 (65/35) | C28000 Muntz Metal | Standard |
|---|---|---|---|
| UNS Designation | C27000 | C28000 | ASTM / CDA |
| Common Names | Yellow Brass 65/35, CDA 270 | Muntz Metal, CDA 280 | – |
| Copper (Cu) | 63.0–68.5% | 59.0–63.0% | ASTM B36 |
| Zinc (Zn) | Balance (~31.5–37%) | Balance (~37–41%) | ASTM B36 |
| Lead (Pb) max | 0.10% | 0.30% | ASTM B36 |
| Iron (Fe) max | 0.07% | 0.07% | ASTM B36 |
| Microstructure | Alpha (FCC) – near boundary | Alpha + Beta (FCC + BCC) | – |
| Tensile Strength (Annealed) | 340–400 MPa | 370–430 MPa | ASTM E8 |
| Tensile Strength (Half-Hard) | 420–480 MPa | 430–520 MPa | ASTM E8 |
| Elongation (Annealed) | 45–60% | 25–40% | ASTM E8 |
| Hardness (Annealed) | 75–95 HV | 90–110 HV | ASTM E92 |
| Electrical Conductivity | 24–26% IACS | 22–26% IACS | ASTM B193 |
| Density | 8.47 g/cm³ | 8.39 g/cm³ | – |
| Melting Range | 900–930°C | 885–905°C | – |
| Sheet / Strip Thickness | 0.3–3.0 mm (strip); up to 6 mm plate | 1.0–8.0 mm sheet/plate | ASTM B36 |
International Equivalent Grades
| Standard | C27000 Designation | C28000 Designation |
|---|---|---|
| USA (UNS/ASTM) | C27000 / CDA 270 | C28000 / CDA 280 (Muntz Metal) |
| Europe (EN) | CW507L (CuZn35) | CW508L (CuZn37) / CuZn40 |
| UK (BS) | CZ107 | CZ109 (Muntz Metal) |
| Germany (DIN) | CuZn35 / WNr 2.0285 | CuZn40 / WNr 2.0360 |
| ISO | CuZn35 | CuZn40 |
| India (IS) | IS 407 Grade 3 (nearest) | IS 291 (Muntz Metal plate) |
| Japan (JIS) | C2700 | C2800 |
| China (GB) | H65 | H62 / H60 |
Product Types and Variants
| Product Type | Description | Typical Size Range |
|---|---|---|
| Busbar Plates (C27000) | Blanked and punched current-carrying plates for LV switchgear | 2–4 mm thick, custom profile |
| Heavy Terminal Strips (C27000/C28000) | Thick-section terminal bars punched with multiple holes | 2–6 mm thick, 20–100 mm wide |
| Panel Hardware Stampings (C27000) | Distribution board frame components and mounting hardware | 1.5–3 mm sheet |
| Earthing Plates (C27000) | Flat earthing plates and ground bars for panel assembly | 2–4 mm, custom hole pattern |
| Architectural Sheet Metal (C27000) | Door kick plates, letter plate blanks, grille panels | 1.0–2.5 mm polished sheet |
| Muntz Metal Plate Parts (C28000) | Blanked and drilled heavy plate components | 2–8 mm plate, custom size |
| Condenser Plates (C28000) | HVAC and marine condenser water box sheets | 2–5 mm plate |
| Precision Blanks (C27000) | Flat circular or profiled blanks for further machining | Dia 10–200 mm, 1–6 mm thick |
Key Features
- C27000: best balance of formability and cost for general sheet metal stampings; alpha-phase microstructure
- C28000 Muntz Metal: highest strength of common brass sheet grades; alpha-beta structure; excellent for heavy plate work
- Both grades RoHS compliant (Pb within limits for C27000; C28000 lead max 0.30% may require REACH declaration)
- Lower copper content than C26000/C26800: competitive pricing advantage for high-volume sheet metal components
- Suitable for tin, nickel, and chrome plating; polished C27000 sheet used for architectural and decorative hardware
- ISO 9001:2015 certified production; ASTM B36 and EN 1652 certified strip supply
- Progressive die, compound die, and shear/punch-press capability for sheet thicknesses 0.3–8 mm
- Secondary operations: deburring, drilling, tapping, polishing, lacquering, tin/nickel plating
Manufacturing Process
Material Procurement and Inspection: C27000 or C28000 strip/sheet/plate sourced from approved mills with ASTM B36 or EN 1652 mill certificates. Thickness, width, hardness, and surface quality checked on receipt. Chemical verification by OES on each heat number.
Blanking and Piercing: Sheet fed into compound die or progressive die (thinner gauge) or shear-blanked on hydraulic press (heavier plate). Blanking clearance 5–8% per side for C27000; 6–10% for C28000 at equivalent thickness, reflecting higher hardness.
Forming and Bending: C27000 strip bent in progressive die or press brake tool. Minimum bending radius for C27000 half-hard: 1.0× material thickness for 90° bends. C28000 sheet: minimum bending radius 1.5–2.0× material thickness due to lower ductility.
Drilling and Tapping: Plate components drilled and tapped for busbar bolt patterns, mounting holes, and grounding studs. Drill speeds and feed rates optimised for brass to avoid work-hardening at hole entry.
Surface Treatment: Deburring by vibratory or belt process; polishing for architectural grades; tin plating for electrical contact components; nickel or chrome plating for corrosion-resistant or decorative applications; lacquering for architectural hardware.
Final Inspection: Dimensional check per drawing; surface finish inspection; plating thickness by XRF; AQL sampling per ISO 2859. Anti-tarnish packing and moisture barrier for export.
Quality Standards and Certifications
| Standard / Certification | Applicability |
|---|---|
| ISO 9001:2015 | Quality Management System |
| ASTM B36 | C27000 and C28000 brass plate, sheet, strip specification |
| EN 1652 CW507L / CW508L | European standard brass plate, sheet, strip |
| IS 291 | Indian standard Muntz Metal (C28000) specification |
| ISO 2768 | General tolerances for sheet metal parts |
| EN 10204 2.2 | MTR with every material batch |
| ISO 2859-1 | AQL inspection sampling plan |
Pricing
C27000 / C28000 Brass Sheet Metal Parts: US$ 15.90 per kilogram (indicative, subject to order quantity, part size, thickness, finish, and secondary operations). MOQ: 50 kg per part number. Contact us with drawings or specifications for a firm quotation within 24 hours.
Frequently Asked Questions
1. What is Muntz Metal and why is it called that?
Muntz Metal (C28000, 60/40 Brass) is named after George Fredrick Muntz, a British industrialist who patented the alloy in 1832 as a lower-cost alternative to copper for sheathing ship hulls. Its 60% copper / 40% zinc composition gives it an alpha-beta microstructure with higher strength than lower-zinc brasses, while remaining cost-effective due to its lower copper content.
2. Can C28000 Muntz Metal be cold-stamped?
Yes, but with limitations. C28000’s alpha-beta microstructure gives it lower ductility than alpha brasses (elongation 25–40% annealed vs 50–65% for C26000). It is suitable for blanking, piercing, light bending, and heavy shearing of plate, but not for deep drawing or complex multi-bend progressive die stampings. It is best used for flat blanked, drilled, and simply formed heavy plate components.
3. Is C27000 susceptible to dezincification?
C27000 at 65/35 composition is near the dezincification boundary. In aggressive environments (soft water, acidic conditions), dezincification is possible. For such environments, a dezincification-resistant grade with arsenic inhibitor (DZR brass, e.g. CW602N or CZ132) is recommended. For dry indoor electrical service, C27000 performs well without inhibitor additions.
4. What is the difference between C27000 and C28000 for electrical busbar applications?
For busbar and terminal applications, C27000 is preferred over C28000 due to its higher electrical conductivity (24–26% IACS vs 22–26% IACS) and better cold-formability for punching and bending. C28000’s higher strength is advantageous for busbar plates subject to mechanical stress, vibration, or bolt pre-load, but its lower conductivity makes it less ideal for current-carrying busbars at the same cross-section.
5. What minimum bend radius is required for C27000 and C28000 sheet?
For C27000 annealed sheet: minimum bend radius 0.5× material thickness for 90° bends. For C27000 half-hard: 1.0× material thickness. For C28000 annealed sheet: minimum bend radius 1.5× material thickness. All values are for bends perpendicular to rolling direction; bending parallel to rolling direction requires larger minimum radii.
Related Products and Linked Terms
- C26000 Brass Stamping (Cartridge Brass)
- C26800 Brass Stamped Parts – Yellow Brass Stampings
- Brass Stampings – Brass Stamped Parts and Components
- Electrical Pressed Switch Parts in Brass
- Brass CNC Machined Parts
- Brass Hot Forged Parts (C28000 Hot-Worked)
Request a Quote
Electrical Accessories India manufactures C27000 / C28000 Muntz Metal brass sheet metal parts – busbar plates, panel hardware, architectural stampings, heavy plate blanks, and custom sheet metal components – for global OEM, EPC, and distribution customers. Indicative pricing: US$ 15.90/kilogram. Contact us with drawings or specifications for a formal quotation within 24 hours.
Email: info@elecaccs.com | Website: www.elecaccs.com