Muntz Brass, also known as Yellow Metal, is a high-strength copper–zinc alloy containing approximately 60% copper and 40% zinc, with small iron additions. Developed by George Muntz in the 1830s, it is valued for durability, strength, and corrosion resistance in marine and industrial environments.
Due to its alpha–beta structure, Muntz Brass offers significantly higher strength than cartridge or alpha brasses, making it ideal for heavy-duty applications where extreme cold forming is not required.
Chemical Composition
| Element | Typical % | Role |
|---|---|---|
| Copper (Cu) | 59 – 61 | Corrosion resistance, ductility |
| Zinc (Zn) | 39 – 41 | Strength, hardness |
| Iron (Fe) | ≤ 0.1 | Grain refinement |
| Lead (Pb) | ≤ 0.1 | Minor machinability improvement |
| Others | Trace | Controlled impurities |
Metallurgical Note: The ~40% zinc content places Muntz Brass in the alpha–beta phase region, giving it much higher strength and hardness than alpha-only brasses.
Physical Properties
| Property | Typical Value |
|---|---|
| Density | ~8.39 g/cm³ |
| Melting Range | 880 – 910 °C |
| Electrical Conductivity | 15 – 20% IACS |
| Thermal Conductivity | ~110 W/m·K |
| Thermal Expansion | ~20 µm/m·°C |
| Magnetic Property | Non-magnetic |
| Color | Yellow-gold |
Mechanical Properties
| Property | Annealed | Cold Worked |
|---|---|---|
| Tensile Strength | 350 – 450 MPa | 550 – 750 MPa |
| Yield Strength | 150 – 250 MPa | 400 – 550 MPa |
| Elongation | 25 – 40% | 5 – 15% |
| Hardness (HV) | 100 – 130 | 160 – 220 |
| Elastic Modulus | ~100 GPa | |
Compared to cartridge brass, Muntz Brass is stronger and harder but less ductile.
Strengthening & Metallurgical Behavior
✔ Dual-phase α + β microstructure
✔ α-phase provides ductility
✔ β-phase provides strength and hardness
✔ Solid-solution strengthening from high zinc content
✔ Cold work increases strength but limits ductility
✔ Not heat-treatable
Key Characteristics
✔ High mechanical strength
✔ Good wear resistance
✔ Excellent hot workability
✔ Cost-effective copper alloy
✔ Moderate marine corrosion resistance
✔ Non-sparking
✔ Suitable for thick and heavy sections
Available Forms
Plates and sheets
Bars and rods
Extrusions and forgings
Marine sheathing plates
Typical sizes:
Plates: 3 mm – 100 mm+
Rods: up to 300 mm diameter
Applications
Marine hull sheathing and condenser plates
Valves, pumps, and bearing housings
Wear plates and heavy-duty fittings
Architectural panels and structural hardware
Non-sparking defense and safety components
Advantages
✔ Higher strength than most brasses
✔ Good seawater corrosion resistance
✔ Economical compared to bronze
✔ Excellent hot-forming capability
✔ Long service life
✔ Fully recyclable
Why Choose Muntz Brass?
Choose Muntz Brass (CuZn40) when your application requires high strength, heavy sections, cost efficiency, and good performance in marine or industrial environments.
Engineering Insight:
Muntz Brass bridges the gap between highly ductile alpha brasses
and high-strength bronzes,
making it ideal for structural and marine components
where deep drawing is not required.
Quick Comparison
| Alloy | Strength | Ductility | Marine Resistance |
|---|---|---|---|
| Cartridge Brass | Medium | Excellent | Good |
| Naval Brass | High | Moderate | Excellent |
| Muntz Brass | High | Moderate–Low | Good |