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Frequently Asked Questions
 APPLICATIONS |
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 Question |
Answer |
See CDA Publication |
| Which is the better copper alloy for use in seawater? | Aluminium bronze and copper-nickel are the most frequently used. Gunmetals, phosphor bronzes and high tensile brasses can also be used. | Pub 30 Copper-Nickel: Applications & Properties |
| What is Nordic gold? | This alloy, used for the new European coins for 10, 20 and 50 cent pieces, has been developed by Outokumpu. The composition is 89% copper, 5% aluminium, 5% zinc and 1% tin. | |
| Which copper alloys are the best bearing materials? | Bearing materials must be strong but have low friction co-efficiency. | Pub 45 Copper Alloy Bearings |
| BEARING METALS |
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Question |
Answer |
See CDA Publication |
| Which bearing alloy should be used against a hard steel shaft? | Phosphor bronze, PB1 or CuSn11P | Pub 45 Copper Alloy Bearings |
| What is OILITEBronze? | A self lubricating (oil-impregnated) bearing material made from powders of copper and tin. | Pub 45 Copper Alloy Bearings |
| Where can I get help on the correct choice of copper alloy bearing material? | Consult CDA UK publication TN 45. | Pub 45 Copper Alloy Bearings |
| BIOFOULING |
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Question |
Answer |
See CDA Publication |
| What copper alloy would you recommend to prevent biofouling? | 90/10 copper-nickel is most usually used. | TN 30 Copper-Nickel Applications &
Properties TN 36 Copper-Nickel Cladding in Ships & Boat Hulls TN 37 Copper-Nickel Cladding for Offshore Structures TN 38 Materials for Seawater Pipelines |
| BRASS |
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Question |
Answer |
See CDA Publication |
| Can brass fittings be cleaned with industrial cleaners? | Yes, but not cleaners that contain ammonia. | Pub 117 The Brasses - Properties & Applications |
| What is common brass? | 64/36 brass. | Pub 117 The Brasses - Properties & Applications |
| What is the annealing temperature for brass? | 500-550oC. | Pub 117 The Brasses - Properties & Applications |
| Which copper alloy has the highest ductility? | 70/30 Brasses CZ106 (CW505L) | Pub 117 The Brasses - Properties & Applications |
| Are the Brasses much weaker than steels? | No, high strength brasses have tensile strengths up to 770 MN/m2 which is much better than many steels. | Pub 117 The Brasses - Properties & Applications |
| What is the difference between brass and bronze? | Brasses are copper-zinc alloys, bronzes are copper-tin alloys. | Pub 117 The Brasses - Properties &
Applications Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| What are the gilding metals and what are they used for? | Copper-zinc alloys (brasses) with up to 20% zinc. | Pub 117 The Brasses - Properties & Applications |
| Which Brass would you recommend for fittings for tubes which have to resist dezincification? | CZ 126 (CW707R) | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| Where can I find companies which produce hot stampings in Brass? | Contact CDA | |
| BUSBARS |
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Question |
Answer |
See CDA Publication |
| What is the maximum DC current rating for a busbar of a given size in still air? | See Pub 22 or the new datadisk. | Pub 22 Copper for Busbars |
| What are the advantages of copper as a Busbar material compared to aluminium? | Higher conductivity, higher operating temperature and low contact resistance. | Pub 22 Copper for Busbars |
| CASTING |
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Question |
Answer |
See CDA Publication |
| Which casting processes are available for copper and copper alloys? | Most common casting techniques including sand, shell, permanent mould, pressure die casting and precision casting, centrifugal and continuous casting. | Pub 42 Copper & Copper Alloy Castings |
| CORROSION RESISTANCE |
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Question |
Answer |
See CDA Publication |
| What material is recommended for condenser tubes cooled by seawater? | 90/10 (or 70/30) copper-nickel alloys. | TN 38 Materials for Seawater Pipelines |
| What material is recommended for underground pipe fittings | Gunmetal or dezincification resistant brass | TN 42 Copper and copper alloy castings |
| Is brass resistant to stress-corrosion cracking? | Yes if cold worked components are stress-relieved at 250-350o for ½ to 1 hour. | Pub 117 The Brasses - Properties & Applications |
| Which copper alloy has the best corrosion resistance in seawater? | The aluminium bronzes are used to meet exacting NES standards. They are especially good in resisting pitting corrosion. | Pub
115 Aluminium Bronze vs Stainless Steels and Ni-Resist in Offshore Seawater Environments Pub 80
Aluminium Bronze Alloys Corrosion Resistance Guide |
| COPPER |
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Question |
Answer |
See CDA Publication |
| Do copper and copper alloys become brittle at low temperatures? | No | Pub 117 The Brasses - Properties & Applications |
| What is the melting point of copper? | 1083°C | |
| Where can I get supplies of copper and copper alloys? | Stockists or manufacturers. Discuss your requirements with CDA Information Service regarding sources in the UK. | |
| Which Grade of copper should be used where welding is required? | A Phosphorous deoxidised copper (C106)-this is CW 006A | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| Will commercial grades of copper become hard (like steel) if they are cooled rapidly after heating? | No. Copper is not susceptible to precipitation hardening. | |
| Why is copper so efficient in heat exchanger applications? | Because the thermal conductivity is so high - it is 23 x better than stainless steel or titanium and 1.6 times better than aluminum. | Pub 122 High Conductivity Copper for Electrical Engineering |
| Which copper alloy has a good electrical conductivity and retains strength up to 400C? | Copper Chromium (CC101)-conductivity is 80% I.A.C.S. - strength good up to 400C. | Pub 122 High Conductivity Copper for Electrical Engineering |
| What effect does heavy cold working have on the electrical conductivity of copper? | It reduces by about 3% | Pub 122 High Conductivity Copper for Electrical Engineering |
| EARTHING SYSTEMS |
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Question |
Answer |
See CDA Publication |
| How should a good earthing system be designed? | A well designed system is needed above and below ground. See publication 119. | Pub 119 Earthing Practice |
| ENERGY EFFICIENCY |
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Question |
Answer |
See CDA Publication |
| How do I save money on electricity bills in my organisation? | Design and specify cable systems, motors and transformers to be efficient. | Pub 116 Electrical Energy Efficiency and programs: |
| HEALTH |
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Question |
Answer |
See CDA Publication |
| Why is Brass recommended for door fittings? | It looks very good and the copper content in Brass acts as an effective bacteriacide so in any environment where health considerations are significant the use of brass door furniture is strongly recommended. | Pub 121 Copper – The Vital Metal |
| How do the antibacterial properties of copper and brass combat toxic E.coli 0157 bacteria? | A recent study found that the highly toxic E.coli 0157:H7 strain of bacteria survive for much shorter periods of time on copper and brass surfaces than stainless steel. This has wide-ranging implications for reducing outbreaks from cross contamination of E.coli in the food processing industry. | |
| What significant antibacterial advantages does copper have over polybutylene plastic and stainless steel in cool potable 'soft' waters? | Copper demonstrated an antibacterial advantage over polybutylene for every temperature range and water hardness condition studied. In all water conditions copper demonstrated either stronger or equivalent antibacterial properties compared to stainless steel. | |
| INFORMATION |
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Question |
Answer |
See CDA Publication |
| Do I have to download all this information? | It is available on CD-ROM and in books from CDA UK Information service. | CDA list of publications |
| JOINING |
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Question |
Answer |
See CDA Publication |
| Which are the recommended practices for welding and brazing copper and copper alloys? | There are many. See publication 98. | Pub 98 Joining of Copper and Copper Alloys |
| LACQUERS |
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Question |
Answer |
See CDA Publication |
| What is ‘INCRALAC’? | A clear acrylic resin finish containing tarnish inhibitor. | TN 41 Clear Surface Finishes |
| MACHINING |
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Question |
Answer |
See CDA Publication |
| Which are the easiest copper alloys to machine? | Free-machining brass sets the standard by which all other metals are judged. | Pub 117 The Brasses - Properties & Applications |
| What tool geometry and speeds and feeds do I use for machining copper alloys? | See publication 44 | Pub 44 Machining Brass, Copper & Copper Alloys |
| POWER QUALITY |
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Question |
Answer |
See CDA Publication |
| How should a system be designed to avoid problems with harmonics? |
Design and size cable systems appropriately. |
Pub 123 Electrical Design – A Good
Practice Guide Pub 142 Section 607 in Residential Installations - Technical Note |
| RECYCLING |
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Question |
Answer |
See CDA Publication |
| Can copper and brass be recycled? | Yes, recycling has been very economic for many centuries. | Pub 121 Copper – The Vital Metal |
| PRODUCTION |
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Question |
Answer |
See CDA Publication |
| Which processes are available to make components | Many different casting, hot working and cold working processes. | Pub 97 Design for Production |
| PROPERTIES |
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Question |
Answer |
See CDA Publication |
| Do copper alloys become brittle at low temperatures? | No. Some properties are enhanced at low temperatures. Copper does not become brittle. | TN 26 The Brasses – Technical Data |
| What is the melting point of copper? | 1083oC. | Pub 122 High Conductivity Copper for Electrical Engineering |
| Which copper alloys are strongest? | Copper-beryllium alloys. | Pub 122 High Conductivity Copper for Electrical Engineering |
| Can copper and copper alloys be hardened by heat treatment? | Some alloys can, including copper-beryllium, copper-chromium and copper-nickel-silicon. Most unalloyed coppers and brasses can only be softened by heating. | Pub 122 High Conductivity Copper for Electrical Engineering |
| High conductivity is needed in electrical equipment running at high temperatures. What grade of copper should be used? | Copper with silver added or copper-chromium. | Pub 122 High Conductivity Copper for Electrical Engineering |
| What is temper as applied to copper and copper alloys? | Strength and hardness increases with the percentage of cold reduction after hot working. Properties are defined in standards. See also CDA publications. | Pub 120 Copper
& Copper Alloys, Compositions, Applications & Properties TN 26 The Brasses – Technical Data |
| What does grain size mean, why is it important for copper? | Copper like other metals is made up of millions of tiny grains. In the case of copper which is to be worked these range in size from 0.01 to 0.1mm. The grain size is particularly important where copper is to be fabricated by cold working - generally the smallest grain size that can be economically fabricated into a desired component is used. | |
| What is the solution treatment temperature? | This term applies to alloys such as Cu-Be and Cu-Cr which are strengthened by age (precipitation hardening). It is the temperature (900-1000C) to which the alloys are heated prior to quenching and ageing. | Pub 122 High Conductivity Copper for Electrical Engineering |
| Where can I learn about the metallurgy of copper alloys including the phase diagrams and heat treatment? | Phase diagrams are in Pub 94. Other details are in pubs 122 and 117. For more info, contact CDA. | Pub 94 Equilibrium Diagrams |
| I have produced some brackets in a fully heat treated Cu_Be alloy C112 which I am unable to bend. Can I soften them sufficiently by annealing? | No, it is recommended that they are solution treated at 850-920 C, then bent to shape and finally aged at 420 to 470C. | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| ROOFING |
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Question |
Answer |
See CDA Publication |
| What is the longest length I can lay a copper gutter/bay without a joint or step? | Depending on the gauge used, for 0.6mm it is 9m and for 0.7mm thickness it is 13m. | Pub 156 Copper Roofing - In Detail |
| Where can I learn about practical copper roofing? | Please contact us for details of courses | |
| What are the fixings required on vertical cladding with high wind loadings? | 7 No 3 holed clip/m2 | Pub 156 Copper Roofing - In Detail |
| What is the life of a copper roof? | Typically, for long strip – 90-100 years, traditional 75-85 years. | |
| How long does it take for patina to form? | The full green colour is achieved within 4-6 years in coastal regions, 8-12 years in cities, 16-20 years in urban areas and 22-30 years in mountainous regions. | Pub 156 Copper Roofing - In Detail |
| How can I prevent patina forming? | Several coats of INCRALAC applied on a carefully prepared surface. | TN 41 Clear Surface Finishes |
| Where can I get a list of copper roofing contractors | See our lists of roofing contractors on this site | |
| What is pre-patinated copper? | Copper sheets 3m x 670mm x 0.7mm are available treated to form a near natural patina that will not wash or rub off. | |
| SAFETY |
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Question |
Answer |
See CDA Publication |
| Can fire sprinklers be installed in homes? | Yes, using the code of practice. | Pub 125 Copper Fire Sprinkler Systems for
Residential & Domestic Properties Pub 107 Fire Sprinkler Systems Pub 147 Copper Residential Sprinkler Systems for Life Safety & Property Protection |
| How often should domestic wiring be given a safety check? | Every 5 years or if concern is caused on any of the 10 points on a checklist. | Pub 131 ECA/CDA Electrical Safety Leaflet |
| SPECIFICATIONS |
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Question |
Answer |
See CDA Publication |
| Are the new BS EN European standards the same as the old British standards? | Most are similar but there are detailed differences. Ask CDA Information, check the standards or Publication 120. | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| What are DGS and NES standards? | Naval engineering standards are prepared for material for the UK Ministry of Defence. They replace Directorate General ships standards. Details from CDA Information or Publication 82. | Pub 82 Aluminium Bronze Alloys Technical Data |
| A copper is specified on a drawing as C110. What is this and is there a UK equivalent? | This refers to the ASTM (American) specification C11000. The UK equivalent is C101-an electrolytic tough pitch conductivity copper. | |
| A drawing for a bearing specifies CuSn10Pb 10. What is this? | A leaded bronze consisting of 10% tin, 10% lead, the balance being copper. designated LB2 or is BSEN CC495K. | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| A Specification describes a brass as CDA 360. What is this? | This is an old CDA Inc(USA) spec. It is now ASTM 36000. The UK equivalent is CZ 124(BSEN CW603N). It is a free machining brass. | |
| How much silver is present in nickel silvers? | None, nickel silvers are copper-nickel-zinc alloys which have an attractive colour when polished. | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| A drawing specifies TUNGUM for a pipe. What is TUNGUM? | TUNGUM is a trade name for aluminium-nickel-silicon brass. CZ127(CW 700R). | Pub 120 Copper & Copper Alloys, Compositions, Applications & Properties |
| A drawing refers to a material as B16. What is this? | B16 is an ASTM specification for free cutting brass rod and bar. | |
| SPRINKLERS |
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Question |
Answer |
See CDA Publication |
| How should a domestic fire sprinkler system be designed? | Correct design and installation techniques will be the subject of a new standard. | Pub 125 Copper Fire Sprinkler Systems for
Residential & Domestic Properties Pub 107 Fire Sprinkler Systems Pub 147 Copper Residential Sprinkler Systems for Life Safety & Property Protection |
| TUBING |
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Question |
Answer |
See CDA Publication |
| Where can I find the maximum water pressure that copper pipes can withstand? | CDA Publications | TN 43 Large Diameter Copper Tubes for Industrial and Commercial Heating Applications |
| How should I design cold and hot water pipe systems? | Good practice is described in several CDA publications. | Pub 33 Copper Tube in Domestic Water Services - Design & Installation |
