CZ 121 Brass Alloys Brass CZ121 Properties

Background of BRASS CZ 121 Alloy 

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.


PRODUCTS MADE FROM CZ 121 BRASS:  Screws Bolts Nuts CNC machined parts Brass precision Components Screw machine products parts Hose barbs Moulding inserts 

Brass Anchors drop in Anchors Fasteners
Brass Anchors Brass Anchor Fasteners
Drop in Brass Anchors Brass Drop Anchors
Brass Earth Blocks
4 way Brass earth blocks
Brass Earthing Blocks earth bar strips
Brass Electrical Accessories
Brass Electrical Accessories
Electrical Fuse Contacts Fuse terminals
Line taps Brass Split Bolts Connectors
Brass Connectors Brass Tunnel Connectors electrical Connectors
Brass Inserts Brass Moulding inserts
Mould in Inserts Brass Plastic Moulding Inserts
Expansion inserts Knurled Brass inserts Expansion moulding inserts
Brass Neutral Links
Neutral Links Brass 1 meter long
Brass Neutral links Single Pole Brass Earth bars Terminal bars
Brass Neutral Links 63 Amp
Brass Nuts
Brass Hex Nuts Brass Nuts
Brass Lock Nuts Brass Cable Gland Hex Lock Nuts
UNI 5587 Brass Nuts Brass Thick Nuts
Brass Pipe Fittings Brass Plumbing Fittings
Brass Radiator Keys Brass Tommy bar Type Rad Bleed Keys
Brass Clock Type Radiator keys
Brass Tank Connectors Water Tank Connectors Fittings
Brass Plugs Brass Stop Plugs Brass Pipe Plugs
Brass Hex Nipple Brass Nipples Equal Pipe Nipples

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. CZ121 is an alpha/beta alloy.

Alloy CZ114

Brass alloy CZ121 is used for machining. It has lead added to the composition to improve machinability. The lead remains insoluble in the microstructure of the brass and the soft particles act as chip breakers.

Alloy CZ121M

The name CZ121M is sometimes used to emphasise its machining properties.

Chemical Composition of Brass alloy CZ121

Table 1. Typical chemical composition for brass alloy CZ121










Properties of Brass alloy CZ121

Mechanical Properties of Brass alloy CZ121

Table 2. Typical mechanical properties for brass alloy CZ121



Tensile Strength (MPa)


Proof Stress (MPa)


Elongation A5 (%)


Hardness VPN


Physical Properties of Brass alloy CZ121

Table 3. Typical physical properties for brass alloy CZ121




8.47 kg/m3

Melting Point


Modulus of Elasticity

97 GPa

Electrical Resistivity

0.062x10-6 Ω.m

Thermal Conductivity

123 W/m.K 

Thermal Expansion

20.9 x10-6 /K 

Alloy Designations

Brass alloy CZ121 corresponds to the following designations:






BS2874 CZ121



Corrosion Resistance of Brass alloy CZ121

The corrosion resistance of Brass alloy CZ121 is fair to excellent.

Fabrication of Brass alloy CZ121

Cold Working of Brass alloy CZ121

Cold working of Brass alloy CZ121 is poor and is not recommended. It can, however, be knurled if required.

Hot Working of Brass alloy CZ121

Fabrication of Brass alloy CZ121 by hot working is excellent. It is recommended that hot working be done between 630 and 730°C.

Heat Treatment of Brass alloy CZ121

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


The machinability of alloy Brass alloy CZ121 is excellent. It has a machinability rating of 90 where Alloy 360 FC Brass is 100.

Welding and Joining of Brass alloy CZ121

Soldering of Brass alloy CZ121 is rated as “excellent” and brazing is “good”. Butt welding is fair but all other welding methods are not recommended.

Applications of Brass alloy CZ121

Brass alloy CZ121 is typically used in:

·         High speed machined components

·         Architectural extrusions

·         Locks

·         Hinges

Supplied Forms

Brass alloy CZ121 is typically supplied by usin the following forms:

·         Round bar

·         Hexagon bar

·         Square bar

·         Flat bar