What is Brass? an in depth technical guide
metals4U stock a wide range of brass profiles for use in the home or commercial workshop, we also stock a comprehensive range of brass handrails and fittings ready for immediate use. We supply CZ108, CZ121, CZ126 and CZ130 grades of brass, and all our stock conforms to the relevant industry standards and specifications.
Brass is an alloy of copper and zinc; the amount of zinc present is the main factor affecting types, or grades, of brass. The use of brass is well documented as far back as the 3rd millennium BCE around the Aegean, Iraq, Georgia and Turkmenistan areas although there have been some isolated finds in China dating back to the 5th millennium BCE. The Roman empire used brass for their coins, and it even gets a mention in the King James' Bible and in some of the works of Shakespeare.
Brass has a very decorative, bright golden lustre; combined with its high workability and durability, it provides a perfect solution for the manufacture of hard wearing components that also may need to be aesthetically pleasing. It is used to make musical instruments, machined parts, boiler parts, fireboxes, ornamental castings, shop fittings, extruded sections, architectural extrusions, fasteners, window frames, stamped components, blanked plates, heat exchangers and general copper-smithing applications. Brass does not 'spark' when it is struck, which makes it suitable for use in hazardous or potentially combustible environments.
Brass has good retention of mechanical and electrical properties at cryogenic temperatures, combined with its non-magnetic properties, brass is well suited for use in electrical and electronic equipment and instruments.
Brass is also renowned for its antimicrobial / bactericidal properties that are effective against MRSA and VRSA- brass kills micro-organisms within a few hours of contact and this antimicrobial effect is continuous in that it does not 'run out'. This antimicrobial action is also affective for bio-fouling resistance which ensures components such as under water pipes and surfaces do not become over-run with algae and barnacles, this helps to dramatically reduce repair and maintenance costs.
There are over 60 types of brass, the most basic categorisation can be considered to group all brasses into three main families, copper zinc brasses (Cu-Zn), Leaded brasses (Cu, Zn, Pb) and tin brasses (Cu, Zn, Sn) these can then be further sub-divided by their more specific properties and uses.
White brass contains more than 45% by weight of zinc and has little significance industrially. It is mainly used as a base for casting alloys and granulated for use in brazing and soldering consumables as it is too brittle for other applications.
Alpha brasses generally contain less than 37% zinc. The microstructure of these brasses is a face centred cubic crystal structure which can be cold worked. Alpha brasses are used for the manufacture of items such as pins, bolts, screws, cold headed components, heat exchangers, fasteners, rivets and other machined parts.
Beta brass contains more zinc than alpha brass; over 45%. Beta brasses can only be hot worked and are less ductile but much stronger than alpha and alpha-beta brasses. These brasses have a body centred cubic crystal structure and are most usually used for the manufacture of castings for parts with complex shapes, water taps, ornamental fountains and water feature structures, and antique and architectural feature replication.
Alpha-beta or 'duplex' brasses contain between 37% and 45% zinc and are made up of both the alpha and beta grain structures. The balance of alpha and beta phase structure is altered by the zinc content. Alpha-beta brasses are harder, have lower cold ductility and more strength than alpha brass. Duplex brass is cheaper than alpha due to the higher zinc content but can be more prone to dezincification corrosion. Alpha beta brasses are suitable for use in the manufacture of hinges, architectural extrusions, gas appliances, radiator valves, taps and pipe fittings.
These groups contain a large class of alloys created by utilising different alloying elements in varying amounts to create a brass with an appropriate property to meet a specific requirement. For example; the addition of tin to inhibit zinc corrosion creates 'Admiralty' brass grades. The addition of iron creates a corrosion resistant and tough, 'Aich's alloy for aggressive marine service applications, the addition of arsenic dramatically improves corrosion resistance without affecting the other properties of the base brass and the addition of lead improves the machinability of some brasses.
Brass has 'very good' to 'excellent' corrosion resistance in most atmospheric and submerged applications. The addition of arsenic elevates its corrosion resistance properties making it suitable for sub soil, subsea, chemical processing and steam turbine use.
A superficial surface tarnish will naturally form on the surface of brass in external applications creating a protective green patina; the underlying brass will be unaffected by the patina and will not rust. To remove or inhibit the development of undesired patina, the brass can be polished by the usual manual and mechanical processes. The use of lacquer will also retard patina growth and preserve the initial natural colour of the brass.
Brass can also be successfully enamelled or plated with chromium, nickel, tin, silver and gold.
As with all metals, cleaning brass should be done by starting with the gentlest process first and slowly moving through to the harsher techniques if the previous options have failed.
First, try a warm water and soap solution applied with a soft cloth in the direction of the grain and buffed dry.
Next try a proprietary metal polish formulated for use on brass; these are widely available commercially.
Finally, the metal can be polished using fine grades of polishing discs and pads; caution should be used when using these forms of surface treatments to ensure the lustre is not damaged by excessive grinding.
All grades of brass can be recycled without losing the integrity of the initial chemical properties. Brass maintains a good proportion of its initial purchase value, swarf and offcuts can also be recycled which will add to the economy of use; this is particularly applicable when working with larger quantities of CZ121 free machining brass.Back to top
CZ108 or CW508L is also commonly known as basic or yellow brass. This very popular grade of alpha brass is often used in cold heading projects and has good hot and cold workability making it suitable for a wide range of applications. These good workability ratings, combined with very good corrosion resistance, reasonable machining qualities and very good bending attributes make it ideal for use in the manufacture of decorative interior and exterior components, radiator tanks, heat exchangers, lamp holders, switch components, blanked plates and wheels and for general copper-smithing.
CZ108 Chemical properties (% weight)
|62.0-64.0||0.30 max||0.10 max||0.10 max||0.05 max||0.20 max||Balance|
CZ108 Physical properties
|Modulus of elasticity||103.4||GPa|
|Proof stress||110 -500||N/mm²|
|Hardness Vickers||55-180||Vickers - HV|
|Tensile strength||300 - 500||N/mm²|
This grade of brass has 'fair' machinability. It has a rating of 35% (free cutting brass has a rating of 100%). Best results are achieved using slow speeds with a very light feed.
CZ108 has high purity which is very well suited to cold forming. This grade is the most common brass to be used in applications where severe bending is required.
CZ108 has excellent cold working properties; it is suitable for cold forming and cold headed manufacturing processes and is easily drawn with very good results.
Hot working fabrication of CZ108 is defined as fair- it can be hot rolled, forged, extruded and drawn.
CZ108 is very malleable and ductile.
All hand and mechanical cutting techniques are suitable to be implemented with this grade, it can also be successfully and easily cut by using gas, flame and plasma cutting equipment.
Hand tools and hack saws can be used without causing excessive work hardening at the cut edge. Many model engineers and jewellers will secure small pieces in a vice or mitre block and score the line to cut with a craft knife, then simply move either side of the score line back and forth until the piece cleanly snaps apart.
The use of carbide blades with bench and table saws is recommended with minimal to no lubrication needed.
If the metal is being milled, the use of a little WD40 or similar lubricant is recommended.
CZ108 can be welded successfully by using all the different techniques of fusion welding. The best results are achieved by soldering and brazing which is defined as 'excellent'. Oxyacetylene is graded as good and gas shielding as fair. Flash butt techniques and spot and seam welding are also both considered to be 'fair'.
CZ108 may require annealing and stress relieving throughout working processes.
To anneal, heat the piece through to 450°C – 650°C and then leave to cool, or continue working the piece. Rapid quench cycles should be avoided as this can cause quench cracks and excessive grain growth.
To complete a stress relieving cycle, the piece needs to be heated through to between 250°C – 300°C for between 30 to 60 minutes, depending on the size and thickness of the piece. If preferred, this can be done by using a hand-held gas torch and heating to medium red, then allowed to cool.
Brass is hardened by work hardening and when heated and then cooled slowly. If age hardening has affected the piece, it will need to be re-annealed to return it to its former state.
CZ108 requires holding in a kiln for a half an hour to an hour, depending on size of the piece, at a temperature of 400° C. Afterwards, remove the piece from the kiln and leave to cool on a fire brick or similar material. Through a process of altering the timings and temperature slightly, a range of tempers can be successfully achieved.
All brasses have a very good to excellent corrosion resistance. Any undesired patina that may naturally occur can be prevented by polishing or applying a lacquer, enamel or a plated surface treatment.
Forging results are classed as 'very good' by both hot and cold forging processes. Stamping techniques are often used with this grade and casting gives very good results within home workshop or industrial manufacturing environments.
CZ108 has excellent brazing properties.
|Workability - Cold||Excellent|
|Workability - Hot||Fair|
|Weldability – Gas||Good|
|Weldability – Arc||Fair|
|Weldability – Resistance||Fair|
CZ108 grade brass products are available in a wide choice of profile and finishes.
Box, tube and sheet are all supplied in mill finish; sheet is also available with a bright or satin polish finish on one face.
Channel is supplied in grade CZ108 HH (Half hard) temper under the specification BS EN 1652: 1998 in a mill finish.
To complement our range of stock CZ108 profiles we supply a comprehensive range of ready-to-use handrails and ball fittings, bar and tube, end caps, finials, flanges, glass clamps, flush fittings, hand and footrail brackets, posts, pillars and adaptors, and fixings to complete shop fitting, joinery and bespoke home and commercial property improvement projects.Back to top
CZ130 or CW624N is a machinable alpha beta or duplex brass. All our CZ130 stock complies with the EN 12167:2011 specification. Duplex brasses have limited colder ductility than alpha grades, however, they have increased hardness and higher tensile strength. This grade has the addition of aluminium that gives the metal a rich golden lustre, so additional polishing is not usually required.
The properties of CZ130 make it ideal for the manufacture of shop fittings, machine parts, instruments, hinges and electrical appliances.
CZ130 Chemical properties (% weight)
|55 - 57||1.6 - 3.0||0.05 - 0.50||Balance|
CZ130 Physical properties
|Modulus of elasticity||GPa|
|Proof stress||150 - 220||N/mm²|
|Hardness Vickers||90-120||Vickers - HV|
|Elongation (A50 mm)||20 - 30||%|
|Tensile strength||350 -420||N/mm²|
This grade of brass has a machinability rating of 90%. (This is graded in comparison to free machining brass which has a rating of 100%)
The formability of this grade is variable depending on whether it is being hot or cold worked. Hot working is rated as excellent and is particularly suitable for the manufacture of very complex shapes by hot extrusion techniques. Cold working is rated as poor to fair.
Alpha/ beta, (or duplex) grades of brass such as CZ130, have limited colder ductility. The ductility is very good during heated applications and hot working.
This grade of brass can be cut using hand tools, bench saws, laser and water jet cutters.
CZ130 has varying results depending on the welding technique employed. Friction welding is rated as good for this grade, however, resistance welding, oxyacetylene, and gas arc welding have poor results and are not recommended. CZ130 maintains excellent results through soldering applications.
CZ130 can be stress relieved or partially annealed by heating the part to 250°C – 300°C for half to one hour and then continuing working the piece or allowing it to cool slowly.
A full anneal can be implemented by heating the piece to between 500°C to 550°C for half to one hour, depending on the size of the piece. A slow cool cycle should follow with no quench cycle as this can cause excessive grain growth and quench cracking.
CZ130 can not be heat-hardened as heating makes brass softer. This grade can be work hardened either by cold working, or to harden it before working, the piece can be heated and then hammered or rolled three to four times to create a hardened state. Care must be taken to not over harden the brass in this way or it will become brittle and may crack.
CZ130 that has been cold worked to a state of hard temper can be partially softened to achieve the desired temper finish.
CZ130 has very good corrosion resistance in most environments. As with all grades of brass, it will not rust but will develop a thin protective surface layer of green patina when used in external environments; this can be polished and cleaned off or the surface of the brass can be surface treated by enamelling, painting or lacquering.
Hot forging of this grade has a designation of 'good' to 'excellent'. The hot forging temperature of brass is 815°C.
Brazing. This grade has good brazing success, when using flux, care should be taken to wash off any remaining flux from the brazed part as this may cause corrosion. Allow the part to lose its heat first or the washing off process may result in a 'quench' cycle causing the part to quench crack
|Workability - Cold||Poor to fair|
|Workability - Hot||Excellent|
|Weldability – Gas||Not recommended|
|Weldability – Arc||Not recommended|
|Weldability – Resistance||Good|
CZ130 brass is available in T section which is supplied in a mill finish.
Angle is stocked in mill finish, bright polish and brushed/dull polish presentations.Back to top
CZ121, or CW614N as it is also known, conforms to BS EN 12164: 2016 and is a free machining brass; it has a 100% machinability rating and is the grade that sets all brass grade machinability ratings. This grade is an alpha beta brass with the addition of lead. The lead remains insoluble within the microstructure during machining which has the additional benefit of working as a lubricant and chip breaker.
CZ121 is suitable for the manufacture of high speed machined components, fasteners, extruded sections, plug pins, switch blocks, hinges and architectural extrusions.
CZ121 Chemical properties (% weight)
|56.5 – 58.5||2.5 – 3.5||0.0 – 0.3||0.7 max||Balance|
CZ121 Physical properties
|Modulus of elasticity||97||GPa|
|Proof stress||230 - 350||N/mm²|
|Hardness Vickers||95 - 159||Vickers - HV|
|Elongation (A 50mm)||15 - 25||%|
|Tensile strength||360 - 580||N/mm²|
CZ121 is the most widely used brass grade in automatic machining. The addition of lead (Pb) to this grade is insoluble in the microstructure and works as a lubricant through machining processes, the soft particles have the added benefit of acting as chip breakers to enable an excellent, smooth machining experience.
This grade is designed for machining, particularly lathe work.
CZ121 gives very good results when knurled. Knurling is a manufacturing process usually performed on a lathe, that rolls a pattern of straight, angled or crossed lines across the surface of a turned part. The indentations created on the work piece enable a better hand or finger grip for ease of use. Knurling can also be used as a form of repair as the raised nature of the pattern compensates for the depressed areas of a work piece due to wear.
Cold working of this grade is poor and not recommended.
Hot working. Results are categorised as excellent for this grade; the optimum hot working temperature is between 630°C and 730°C.
As an alpha/ beta or duplex brass grade, CZ121 has limited cold ductility.
This grade of brass can be successfully cut using all types of machine cutting techniques and hand tools such as hack saw, snips, and shears; on smaller pieces the 'score and snap' technique can be used.
Welding. This grade has less weldability than some other brass grades. Oxyacetylene, resistance, and resistance spot and seam welding is not recommended. Butt welding is possible with 'fair' results. Brazing is good, and soldering is excellent. The applications this grade is used for would not usually require a welding process to be necessary.
If welding is attempted, it is worth noting that this grade does contain lead. To reduce the risk of succumbing to the effects of 'welder's flu' all processes should be undertaken in a well-ventilated work space with the relevant PPE and safety precautions in place.
If annealing is required, a full anneal cycle can be performed by holding at between 430°C and 550°C for ½ to I hour, followed by a slow cool.
A stress relieving anneal cycle can be carried out at between 250°C to 330°C for 30 to 60 minutes and slow cooled.
CZ121, as with all brasses, cannot be heat hardened. The brass will harden through work hardening, particularly through cold working applications.
By heating the brass to 400°C for ½ to 1 hour, the piece can be successfully tempered to best suit the application it was manufactured for. The timings and temperature can be altered to achieve the desired temper designation.
CZ121 has good corrosion resistance.
Forging. This grade is suitable for hot forging, the recommended hot forging temperature is between 625°C and 725°C.
The results from brazing CZ121 is categorised as 'very good'. Care should be taken to wash off any remaining flux once the piece has cooled to reduce the risk of corrosion. It is recommended this is not done while the piece is still hot as quench cracking may occur.
|Workability - Cold||Poor|
|Weldability – Gas||Not recommended|
|Weldability – Arc||Not recommended|
|Weldability – Resistance||Not recommended|
Angle, flat bar, hexagon, round bar and square are all supplied in a variety of lengths and dimensions in a mill finish.
Angle is also available from stock in a bright or brushed polish finish.Back to top
CZ126, also known as CW707R, is an alpha brass with the addition of a small amount of arsenic to improve corrosion resistance without affecting ductility or formability. The improved resistance to dezincification corrosion makes this grade of arsenical brass suitable for use in most waters, including subsea and underground applications. The high strength and very good ductility make CZ126 suitable for use in heat exchangers, condensers, general purpose tube applications, chemical processing components, underground applications, under fresh and sea water apparatus, and steam turbine components. CZ126 is a tube grade brass.
CZ126 Chemical properties (% weight)
|69.0 – 71.0||0.0 – 0.07||0.0 – 0.06||0.02 – 0.06||28.50 – 30.9|
CZ126 Physical properties
|Specific heat||375||j/kg. °K @20° C|
|Modulus of elasticity||114||GPa|
|Hardness Vickers||130||Vickers - HV|
|Elongation (A 50mm)||40||%|
CZ126 is graded as having 25% machinability which gives it a rating of poor to fair.
The formability of this grade overall is good.
Hot working. This grade gives fair results for hot working applications and a working temperature of 750°C – 870°C is recommended.
Cold working. CZ126 has excellent cold working capacity and can be manipulated effortlessly by several cold working techniques, particularly crimping, flanging, riveting, coining, and cold extrusion
CZ126 has very good ductility.
All usual hand, mechanical and flame cutting techniques are suitable for use on this grade.
Welding. Welding of this grade is not recommended as only 'fair' results will be achieved; brazing, soldering and other metal joining processes are all suitable alternatives.
If an anneal process is necessary during fabrication the work piece should be held at between 450°C and 680°C for between1-3 hrs depending on the size and thickness of the metal. The metal should be allowed to slow cool in air.
A stress relief anneal can also be completed on this grade. This is done by holding the work piece at between 200°C -300°C for 1-3 hrs depending on size and allowed to air cool slowly or continued to be worked with further stress relief cycles as required.
CZ126 will not heat harden, however, it will work harden with varying results during hot and cold working.
This grade is supplied pre-annealed.
The addition of arsenic to this grade of brass elevates its corrosion resistance to excellent without affecting strength or ductility.
Cold forging of CZ126 is excellent, techniques such as closed die forging can be completed with particularly successful results.
Hot forging of this grade is rated as fair.
Excellent results are achieved by brazing this grade of arsenic brass. Soft and hard soldering is also rated as excellent.
|Workability – Cold||Excellent|
|Workability – Hot||Fair|
|Machinability||poor to fair|
|Weldability – Gas||Not recommended|
|Weldability – Arc||Not recommended|
|Weldability – Resistance||Not recommended|
CZ126 is supplied as tube profile in a mill finish.
|Welding,Brazing and soldering Brass to||Consumables most commonly used.|
|Brass||Sifmig 8, sifmig 328, Hilco Bronsil, sifsilcopper no 8, sifphosphor bronze 82|
|Stainless steel||Sifmig 8, sifmig 316, sifphosphor bronze 8, sif silcopper 968|
|Bronze||Sifphosphorbronze no 8 & sifsilcopper flux. Silver solder no 39 & silver solder flux|
|Copper||Sifmig 8, sifphosphorbronze no8.|
|Aluminium||Hilco aluminil si 12|