Background

Brasses are alloys of copper and zinc. They may also contain small amounts of other alloying elements to impart advantageous properties. Brasses have high corrosion resistance and high tensile strength. They are also suited to fabrication by hot forging. Free machining grades of brass set the standard for machining, by which other metals are compared.
Brass Classes

Brasses are divided into two classes. The alpha alloys, with less than 37% zinc, and the alpha/beta alloys with 37-45% zinc. Alpha alloys are ductile and can be cold worked. Alpha/beta or duplex alloys have limited cold ductility and are harder and stronger. CZ131 is an alpha/beta alloy.
Alloy CZ131

The composition of brass alloy CZ131 has been designed to provide a compromise between machinability and strength. Thus, it can be used in applications when machinability and riveting are required.
Chemical Composition

Table 1. Typical chemical composition for brass alloy CZ131

%


CZ131

Cu


62

Pb


2

Sn


-

Fe


-

Al


-

Mn


-

Zn


Balance

Si


-

Ni


-

Properties
Mechanical Properties

Table 2. Typical mechanical properties for brass alloy CZ131

Grade


CZ131

Tensile Strength (MPa)


380

Proof Stress 0.2% (MPa)


210

Elongation A5 (%)


25

Hardness VPN


110-130
Physical Properties

Table 3. Typical physical properties for brass alloy CZ131

Property


Value

Density


8.5 g/cm3

Melting Point


885°C

Modulus of Elasticity


105 GPa

Electrical Resistivity


0.066x10-6 Ω.m

Thermal Conductivity


115 W/m.K at 100°C
Alloy Designations

Brass alloy CZ131 corresponds to the following designations:

CEN


BS


UNS


ISO

CW606N


CZ131


C35300


CuZn37Pb2
Corrosion Resistance

Corrosion resistance is rated from fair to excellent in most environments.
Fabrication
Cold Working

CZ131 has only a fair rating for cold working.
Hot Working

Hot forming of CZ131 is poor.
Heat Treatment

Solution treatment or annealing can be done by rapid cooling after heating to 430-600°C.
Machinability

This alloy has a machinability rating of 90 when Alloy 360 FC Brass is 100.
Welding and Joining

Soldering of CZ131 is rated as “excellent” and brazing is “good”. Butt welding is fair but all other welding methods are not recommended.
Applications

CZ131 is typically used in:

· Fasteners

· Rivets

· Domestic appliances

· Automotive engineering

· Hose fittings

· Intricate parts such as clock components
Supplied Forms

CZ131 is typically supplied by Aalco in the following form:

· Round bar