Copper Development Association

Copper Alloys in Refrigeration

CDA Technical Note TN14, 1972

Please note this publication is providedas an archive copy. The informationgiven may therefore not be current.

Copper Alloys in RefrigerationCDA Technical Note TN14

November 1972, Reprinted June 1976

Copper Development AssociationCopper Development Association is a non-trading organisation sponsored by the copper producers andfabricators to encourage the use of copper and copper alloys and to promote their correct and efficientapplication. Its services, which include the provision of technical advice and information, are available tothose interested in the utilisation of copper in all its aspects. The Association also provides a link betweenresearch and user industries and maintains close contact with other copper development associationsthroughout the world.

Website: www.cda.org.uk

Email: helpline@copperdev.co.uk

Copyright: All information in this document is the copyright of Copper Development Association

Disclaimer: Whilst this document has been prepared with care, Copper Development Association can giveno warranty regarding the contents and shall not be liable for any direct, indirect or consequential lossarising out of its use

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Contents

Introduction .................................................................................................................................................2

Refrigeration Sytems and Heat Exchangers..............................................................................................3The Basic Vapour Compression System........................................................................................................3Heat Exchangers in Vapour Compression Refrigeration Circuits..................................................................3

Evaporators ...............................................................................................................................................3Condensers ................................................................................................................................................4Suction/liquid Heat Exchanger..................................................................................................................4

Materials of Manufacture...........................................................................................................................4Plain tubes .....................................................................................................................................................4Bimetal tubes .................................................................................................................................................5Extended surface tubes ..................................................................................................................................5Ribbon tubes..................................................................................................................................................5Integrally finned tubes ...................................................................................................................................5Wire wound tubes..........................................................................................................................................6Internally finned tubes ...................................................................................................................................6Fin and tube construction ...........................................................................................................................6Round tube forms ..........................................................................................................................................6Flat tube forms...............................................................................................................................................6Formula for Calculating Thickness of Tubes Subjected to Internal Pressure .......................................7Copper ...........................................................................................................................................................7Copper Alloys................................................................................................................................................7Fittings, valves and flanges .........................................................................................................................8Primary refrigerants .......................................................................................................................................8Secondary refrigerants (full strength sea water, brackish water, and calcium and sodium chloride brines) ..8

Wrought components ................................................................................................................................8Cast components .......................................................................................................................................8

Natural fresh waters....................................................................................................................................9

Jointing .........................................................................................................................................................9

Corrosion resistance and compatibility .....................................................................................................9Primary refrigerants .......................................................................................................................................9Secondary refrigerants and coolants ............................................................................................................10

Calcium and sodium chloride..................................................................................................................10Ethylene and propylene glycol ................................................................................................................11Methylene chloride, trichloroethylene and trichlorofluoromethane ........................................................11

Joining techniques .....................................................................................................................................11Soldering .....................................................................................................................................................11Brazing ........................................................................................................................................................12Welding .......................................................................................................................................................12British Standard specifications.................................................................................................................14

Tables of Material Properties...................................................................................................................15

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IntroductionThe thermal properties, corrosion resistance and ease of fabrication and joining allow the use ofcopper and copper alloys in a wide range of refrigeration plant applications. This publicationbrings together into one volume information to enable the refrigeration plant designer andmanufacturer to assess the suitability of these materials for particular refrigeration applicationsdown to about -40°.

This technical note has been prepared by the Refrigeration Working Group set up by theMechanical Engineering Industry Committee of Copper Development Association, and thegratitude of the Association is recorded to the Group members for their cooperation andassistance.

The following organisations were represented on the Working Group:

Custom Coils Ltd

Imperial Metal Industries (Kynoch) Ltd

Refrigeration Appliances Ltd

Searle Products Ltd

Serek Ltd

Yorkshire Imperial Metals Ltd

Copper Development Association

The Group reviewed available information on the properties of copper-base materials requiredfor the design of copper alloy refrigeration plant components and the opportunity was taken toconvert all data into SI Units. The Association wishes to thank the following firms whosupplied information in the form of replies to a questionnaire:

F H Biddle Ltd

Carrier Engineering Co Ltd

Carter Thermal Engineering Ltd

Delaney Gallay Ltd

Dunham-Bush (Manufacturing) Ltd

Frigidaire Division of General Motors Ltd

J & E Hall Ltd

The Lightfoot Refrigeration Co Ltd

Marston Excelsior Ltd

Ozonair Engineering Co Ltd

L Sterne & Co Ltd

J Samuel White & Co Ltd

York Division of Borg-Warner Ltd

CDA welcomes enquiries and offers assistance to designers in making the most effective use ofcopper alloys in refrigeration plant and associated equipment.

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Refrigeration Sytems and Heat Exchangers

The Basic Vapour Compression SystemRefrigeration involves the transfer of heat from a low temperature source to a highertemperature sink and an external source of energy is required to carry out this process. Thevapour compression system is most commonly used, with a compressor supplying the energy. Arefrigerant capable of being condensed at a temperature above that of the cooling medium actsas the working fluid. Absorption systems are not considered here as they normally employaqueous ammonia solutions for which copper is unsuitable.

The basic cycle consists of the removal of heat at constant pressure by liquefying the refrigerantin the condenser. This is followed by expansion through a regulating valve, with the absorptionof heat at a constant lower pressure by boiling in the evaporator. The refrigerant is thenrecompressed, returned to the condenser, and the cycle is repeated.

Figure 1 – A basic vapour compression refrigeration system

Heat Exchangers in Vapour Compression Refrigeration Circuits

EvaporatorsOwing to the varying requirements and applications many types of evaporators aremanufactured which may be classified as below (see Table U). The secondary fluid media beingcooled may consist of liquids (L) or gases (G).

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Extended internal surface tube is used in conjunction with plain, individual external fin andexternal continuous fin and tube.

Other specialist designs include embossed plate, attached tube to plate, and tube cast in block.

CondensersCondensers are normally of similar construction to the evaporators detailed below. Theevaporative type using water sprayed banks of tubes employs the construction as given underrectangular bank but in this case internal secondary surfaces are rarely used.

Suction/liquid Heat ExchangerFor some applications a comparatively small heat exchanger is used to transfer heat from the hotliquid, before it enters the expansion device, to the cold suction vapour leaving the evaporator.

Table U

Type PlainTube

Individualexternal

fin

Externalcontinuousfin & tube

Extendedinternalsurface

Shell and tube L L & G LShell and coil L LDouble pipe L L LRectangular bank L & G L & G G L

Materials of Manufacture

Plain tubesIt is usual for plain, round tube to be used in the construction of shell and tube, shell coil andcoil type heat exchangers. Depending upon the service conditions, the following copper alloysare most widely used for these tube applications:

• C106 Phosphorus deoxidised non-arsenical copper

• CZ110 Aluminium brass

• CZ111 Admiralty brass

• CZ126 Special 70/30 arsenical brass

• CN102 90/10 Copper-nickel-iron

• CN107 70/30 Copper-nickel

• CA102 7 % Aluminium bronze

It must be emphasized that copper and copper alloys are not recommended for service in contactwith ammonia but are entirely suitable for use with most other primary refrigerants (see bimetaltubes). Seamless tubes are available in all the above materials and in addition some are formedfrom strip and then welded using high frequency welding techniques.

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Bimetal tubesIn primary heat exchangers handling ammonia, plain steel tubes are frequently used. However,in some applications it is necessary to employ bimetal tubes, having steel in contact with theprimary refrigerant and a copper alloy exposed to the other fluid. One such application is inmarine refrigeration condensers where materials resistant to sea water corrosion are essential.

Extended surface tubesIn heat transfer involving a liquid or an evaporating or condensing refrigerant and air or othergas, there is considerable advantage in providing some form of finning of the tubes. Theextended surface provided by the fins is always in contact with the air or gas. A similar, butusually somewhat lesser advantage may be obtained in the case of heat exchange between anevaporating or condensing refrigerant and a low viscosity liquid such as water. In this case theextended surface is in contact with the refrigerant.

Ribbon tubesA type of extended surface tube used particularly in the construction of larger air-cooled or air-cooling heat exchangers has a metal ribbon wound edgewise on to the tube in the form of ahelix. Since heat must be conducted efficiently along the ribbon in a radial direction, a materialof high thermal conductivity is desirable. For this reason, and because of its comparatively lowcost, commercially pure aluminium is the most frequently used material. In some environments,for example in shipboard applications, aluminium is not sufficiently corrosion resistant and acopper ribbon is then used. In all cases a good thermal contact must exist between the ribbonand the tube on which it is wound. For operation at metal temperatures below 100°C the L-shaped fin is most commonly used with aluminium ribbon, whereas above this temperature, theribbon is peened into the groove. Although these methods are also employed with copperribbon, it is more usual for the ribbon to be wound edgewise on to the tube and the joint madeby soldering or brazing.

Integrally finned tubesInstead of winding a separate ribbon on to a bare tube, a form of finned tube is available inwhich helical fins are extruded from the tube itself by a rolling process. Tubes with findimensions comparable to ribbon tubes are made by this process in both aluminium and copper.For refrigerant-to-liquid heat exchange applications, tubes with much lower fins, resembling athreaded tube, are produced by the same process in a variety of materials including copperalloys and stainless steel. All the extended surface tubes described above can be made inbimetal form with a dissimilar metal liner.

Integrally finned tube

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Wire wound tubesA tube construction adopted for some refrigeration heat exchangers makes use of extendedsurface in the form of rectangular loops of wire helically wound and soldered on to the tube.Copper wire is employed to give high conductivity and thereby maximise the efficiency of thisform of extended surface.

Internally finned tubesHeat exchangers used particularly as water chillers have fins within the tube bore as analternative to the low finned construction. These fins are made from copper foil strip, obliquelycorrugated and then twisted into a spiral form. After fitting inside the tube, contact between finand tube wall is obtained by inserting a small tube into the core formed within the twisted stripwhich is subsequently expanded hydraulically.

An alternative form of internal fin consists of a star-shaped aluminium section twisted along itslength and mechanically bonded to the copper tube to give good heat transfer across theinterface.

Internally finned tube

Fin and tube construction

Round tube formsProbably the most widely used type of heat exchanger in the refrigeration industry is made froma stack of regularly spaced aluminium fins pierced with a pattern of holes sized to receive theround tubes. The copper tubes are inserted through the holes and expanded either mechanically,by passing a stepped plug through the bore, or by the application of hydraulic pressure. Acomplete heat exchanger, used either as an aircooled condenser or an evaporator, can beconstructed by linking individual tubes together by copper U-bends brazed to the tubes.

Flat tube formsFlat sided tubes are employed in place of round tubes for some applications. In this case thejoints between the tubes and fins are brazed. Where both tubes and fins are of steel, brazingwith copper can be carried out in a controlled-atmosphere furnace. A further use of flat sidedtubes is in the tube - and - centre type where the tubes are interleaved with corrugated foil fins,the whole assembly being brazed together. This form of construction is confined almostentirely to vehicle air conditioning systems and is normally made from aluminium.

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Formula for Calculating Thickness of Tubes Subjected toInternal PressureThe effects of operating conditions on the mechanical properties of copper and copper alloysinfluence the decision on the maximum permissible working stress.

However once a design stress has been selected, and if the maximum working pressure andexternal diameter of the tube are known, the thickness required to withstand the appliedpressure can be determined.

CopperBritish Standard BS 2871 :Part I specifies copper tubes in the following three conditions:

1. Half hard (½H) light gauge copper tubes supplied in straight lengths.

2. Half hard (½H) copper tubes in straight lengths and annealed (O) copper tubes in coilssuitable for burying underground.

3. Hard drawn (H) thin wall copper tubes supplied in straight lengths, and not recommended forbending.

The maximum working pressures at temperatures up to 65°C have been calculated from thefollowing formula and are quoted in the relevant Tables (Table X, Table Y and Table Z) in thestandard.

P = tD

Ft−

20

F = stress (N/mm2) t = thickness (mm)

P = pressure (bar) D = outside diameter (mm)

For H condition F = 72.5 N/mm2

For ½H condition F= 60 N/mm2

For O condition F = 46 N/mm2

Note: If tubes in the ½H or H condition are to be annealed during fabrication then the stressvalue quoted for the O condition should be used in the calculation of the working pressures.

The above formula and stress values (F) can be used also for calculating the maximum workingpressures for copper tubes contained in BS 2871 :Part 2 Tables 3 and 4. The maximumoperating pressures and temperatures for Tables 5 to 10 are quoted in each individual table.

Copper AlloysThe following values of F for copper alloys, converted from values given in BS 3274: 1960, canbe substituted in the equation above and used for the various copper alloys given in BS 2871:Part 2:

CZ110 Aluminium brass 86 N/mm2

CZ126 Special 70/30 arsenical brass 86 N/mm2

CN102 90/10 Copper-nickel-iron 73 N/mm2

CN107 70/30 Copper-nickel 97.5 N/mm2

CA102 7% Aluminium bronze 86 N/mm2

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The above values are for annealed materials (O) under steady pressure conditions attemperatures up to 65°C and no allowance has been made for pressure surges due to resonance,inertia, etc. Factors of safety should be applied to the working pressures to cater for anyabnormal operating conditions, and reduced values of F for higher operating temperatures canbe obtained from BS 3274: 1960 Table 11. The values quoted for use up to 65°C may be usedfor operating temperatures down to -40° as copper alloys generally have improved strength atlow temperatures.

Fittings, valves and flangesThe suitability of copper and copper alloys for the above components will depend upon theenvironments and these are grouped under the following headings:

Primary refrigerantsCopper and copper alloys may be used with halo carbon compound refrigerants Nos. 11, 12, 13,13BI, 22 and 114 and azeotrope refrigerants Nos. 500 and 502. Under normal refrigeratingconditions there are no particular corrosion hazards and fittings to BS 864 should be used withpreference for capillary or manipulative type fittings.

Note: Copper and copper alloys are unsuitable for use with Refrigerant No. 707 (ammoniaNH3) and care should be taken to exclude copper and copper alloy pipes and fittings from plantexposed to ammonia and ammonia compounds.

Secondary refrigerants (full strength sea water, brackish water, andcalcium and sodium chloride brines)The following copper alloys are recommended for valves, flanges and other types of fittingssuch as thermometer pockets and air vents conveying the above fluids. These components are tobe used in conjunction with aluminium brass, 90/10 copper-nickel-iron or 70/30 copper-nickelpipework to BS 2871:1971 Part 3 (metric units).

Wrought componentsThe compositions for the material designations quoted are given in the various British Standardsfor wrought copper products BS 2870-5:1968-71 (metric units).

Aluminium brass CZ110

90/10 Copper-nickel-iron CN102

70/30 Copper-nickel CN107

Aluminium bronze CA101, CA102

Phosphor bronze PB 102, PB 104

Cast componentsThe compositions for suitable non-dezincifiable cast alloys are given in the following tables inBS 1400: 1969 (metric units):

Table 5 Group 'A' castings - alloys in common use (preferred for all general purposes).

Table 6 Group 'B' castings - special purpose alloys (for applications requiring their particularproperties).

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Table 7 Group 'C' castings - alloys in limited production.

General guidance on the suitability of the various alloys to different environments, includingnatural waters and sea water, is given in BS 1400:1969 (metric units) Appendix Gl-General.The user is recommended to consult the supplier unless he has previous experience of thebehaviour of copper alloys in the particular environment concerned.

Proprietary alloys not conforming to the above specifications, but which are considered to be atleast equal in corrosion resistance and strength to the above materials in either wrought or castform, may also be used. These should be selected on the advice of the manufacturer.

Natural fresh watersCopper tubes and proprietary copper and copper alloy components are perfectly suitable for allnormal fresh waters.

Note: Aluminium brass tubes are not recommended for fresh water service pipelines, but can beused for service with condensates and distilled water and in coolers where the fresh water beingcooled circulates in a closed circuit. Dezincification may be a problem with certain fresh watersand advice should be sought regarding the cooling water conditions before a unit is supplied sothat non-dezincifiable materials can be used if necessary.

JointingProprietary soft solder fittings to BS 864:Part 2:1971 (integral or 'end feed') using solders to BS219:1959 can be used for low pressure applications. Compression type fittings (manipulative ornon-manipulative) to BS 864:Part 2:1971 are also suitable for a wider range of applications.

Silver brazing alloys to BS 1845:1966 Table 2 Group AG are satisfactory for jointing coppertubes and components. In addition copper phosphorus brazing alloys to BS 1845:1966 Table 3Group CP can be used for copper to copper joints.

Copper and copper alloy flanges to BS 4504:1969 and composite flanges can be attached bysilver brazing and welding techniques depending upon operating temperature conditions. Softsoldering is only recommended for low pressure applications. Where dezincification may be aproblem, fittings and jointing techniques should be used as under "full strength sea water, etc".

Corrosion resistance and compatibilityThe inherent resistance of copper alloys to corrosion is basically due to the formation ofinsoluble protective films in many different environments. Copper alloys will not only beselected for a particular application because of their corrosion resistance, but also for a numberof other properties such as high thermal conductivity, ease of forming and joining machinabilityand mechanical strength.

This section is concerned with the more common operating conditions and environments foundwithin refrigeration plant and the following points should be borne in mind when consideringpotential applications for copper alloys.

Primary refrigerantsSince the early days of refrigeration a number of fluids have been used as primary refrigerants,including air, carbon dioxide, methyl chloride and sulphur dioxide. Today, however, the mostcommonly used refrigerants are the halogenated hydrocarbons (see Table V below), and in largeindustrial plant, ammonia.

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The quoted (V) refrigerants, together with other halogenated hydrocarbons and azeotropes incurrent production, may be used under normal conditions with copper and copper alloys.Advice on limiting operating conditions should be sought from refrigerant manufacturers.

Note: Copper and copper alloys are unsuitable for use in contact with Refrigerant 717Ammonia (NH3). However, copper alloys are often the most suitable materials for handlingsome cooling media (particularly sea water). In such instances, heat exchangers may beconstructed from bimetal (mild steel/aluminium brass) tubes and other components. Thiscombination of materials provides ample resistance to corrosion by each of the fluids.

Table V

Refrigerantnumber

Type Name Formula

11 Halo carbon compounds Trichlorofluoromethane CCI3F

12 Dichlorodifluoromethane CCl2F2

13 Chlorotrifluoromethane CCIF3

13B1 Bromotrifluoromethane CBrF3

22 Chlorodifluoromethane CHCIF2

114 Dichlorotetrafluoroethane CCl2FCF3

502 Azeotropic mixture Refrigerants 22/115 (48.8/51.2%) CHCIF2/CClF2CF3

Secondary refrigerants and coolantsA secondary refrigerant is an intermediate fluid used to remove heat without evaporation. Thisheat is subsequently transferred to an evaporating refrigerant in a heat exchanger.

Air is probably the most commonly used secondary refrigerant and coolant and copper alloyshave good corrosion resistance to normal land and marine atmospheres, but further adviceshould be sought when operating in contaminated industrial atmospheres.

The compatibility of some other secondary refrigerants and coolants is given below.

Calcium and sodium chlorideThese secondary refrigerants should be maintained in an alkaline condition as denoted on thepH scale. pH 7 represents the neutral point and values greater than 7 are alkaline, and less than 7are acid in content. The scale used is logarithmic and hence pH 5 is ten times more acid than pH6 as measured by the hydrogen ion content.

Water solutions of calcium and sodium chloride are widely used and in the neutral condition areeffectively non-corrosive. However, contamination by air and carbon dioxide can vary thecorrosive effect of these solutions. Brines can be inhibited by the addition of sodium chromateor dichromate to maintain an alkaline condition (pH 7-8.5), with the dichromate requiringfurther additions of caustic soda for conversion to active chromate in solution.

Although copper alloys are less susceptible than steel, monthly testing and adjustments of thebrine solutions should be carried out to reduce the potential corrosion hazard. Calcium chloridefreshly prepared is normally alkaline, but dilute solutions readily absorb carbon dioxide andoxygen, eventually making the brine acid.

If an alkaline pH cannot be maintained, copper should not be used for carrying salt brines.

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Ethylene and propylene glycolThese refrigerants require inhibiting for corrosion control, otherwise they are subject tooxidation by air to form acidic end products. The additives may be classed in two categories, a)inhibitors and b) environmental stabilisers or adjusters. The inhibitors act by forming a surfacebarrier protecting the metal from attack and this is normally obtained by reinforcing the oxidefilm. The stabilisers decrease corrosion by stabilising the overall environment. An alkalinebuffer such as borax is a simple example, and chelating agents may also function as stabilisers.

Methylene chloride, trichloroethylene and trichlorofluoromethaneThese refrigerants do not show any general corrosive tendencies if they are not allowed tobecome contaminated with impurities such as moisture.

Joining techniquesThe copper alloys commonly used in refrigeration plant are grouped together in the followingsix main categories for the purpose of defining the methods of joining. These main categoriesare subdivided for special alloys as required (see Table W below).

Table W

Alloy group Wrought formsBS 2870-2875

Cast forms BS 1400

1. Copper C106

2. Silicon bronze CS101

3. Tin bronzes and Gunmetals PB101, PB102 PB4, LPB1, LG2, PB1, CT1, LG1, G1

4. Aluminium bronzes CA101, CA102, CA106 AB1, AB2, CMA1, CMA2

5. Brasses CZ105, CZ110, CZ112,CZ119, CZ126

SCB1, SCB3

6. Cupro nickels CN102, CN107

SolderingAlthough all the quoted (Table W) copper alloys can be soldered, the ease with which theprocess can be carried out depends upon the type of surface film formed on the various alloys(see Table X).

Table X

Alloy group Film Method of removal1. Copper Oxide Zinc chloride activated resin fluxes or

hydrazine hydrochloride type (10% in water)

2. Silicon bronze Silica rich oxide Abrade or pickle surface. Followed by activeflux eg zinc chloride or orthophosphoric acid

3. Tin bronzes and gunmetals Oxide As for copper

4. Aluminium bronze Alumina rich oxide As for silicon bronze

5. Brasses (except Al brass) Oxide As for copper

Aluminium brass Alumina rich oxide As for silicon bronze

6 Cupro nickels Oxide As for copper

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BrazingMost of the copper alloys used in refrigeration plant can be brazed as shown in Table Y below.

The choice of filler alloy within each group depends upon a number of parameters including themethod of heating and joint gap, but all alloys in Group AG are metallurgically compatible withcopper alloys.

On the other hand Group CP alloys have been developed primarily for brazing copper withwhich they are self fluxing. They are seldom used on copper alloys, and should not be used onalloys containing about 2 % nickel or iron because of the risk of formation of brittle phosphidephases.

Table Y

Alloy group Filler type Flux1. Copper BS 1845: Group CP

(Copper phosphorus brazing alloys)BS 1845: Group AGSilver brazing alloys)

Self fluxing

Alkali fluoride type

2. Silicon bronze BS 1845: Group AG Alkali fluoride type

3. Tin bronzes and Gunmetals

BS 1845: Group AG Alkali fluoride type

Note: Care must be taken when brazing alloys containing more than 1% lead eg LPB1, LG2 and LG1,since overheating or undue thermal stressing may give rise to excessive oxidation of lead and thepossibility of parent metal cracking.

4. Aluminium bronze BS 1845: Group AG 'Aluminium bronze ' grade fluoride flux

Note: Aluminium bearing alloys should be brought rapidly to brazing temperature to prevent excessivedilution of the brazing alloy by aluminium from the parent metal which may weaken the bond.

5. Brasses BS 1845: Groups CP 8 AG Alkali fluoride type

Note: Care must be taken when brazing alloys containing more than 1 % lead eg CZ119 sinceoverheating or undue thermal stressing may give rise to excessive oxidation of lead and the possibility ofparent metal cracking.

6. Cupro nickels BS 1845: Group AG Alkali fluoride type

Note: Proprietary silver brazing alloys not at present covered by British Standard containing a 3% nickeladdition have improved corrosion resistance and are recommended for use in sea water and marineenvironments.

WeldingCopper and copper alloys may be fusion welded using metal-arc, oxy-acetylene and gas-shielded arc techniques. Gas-shielded arc welding has largely replaced metal-arc and oxy-acetylene welding in applications where joints of high quality and reliability are required.Argon, nitrogen and helium are used as shielding gases for welding copper. Argon, andsometimes helium, is used for welding copper alloys. Mixtures of these gases are also used.

Table Z gives details of the filler alloys as contained in BS 2901: Part 3:1970.

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Table Z

Alloy group Filler metal composition % (main constituents) BS 2901designation

Remarks

0.15-0.35 Mn/0.2-0.35 Si C7 For use with argonor helium

0.1-0.3 AI/0.1-0.3 Ti/Bal Cu C8 For use withnitrogen orargon/nitrogenmixtures

1. Copper

0.02-0.1 B/Bal Cu C21 For use with argonor helium

2. Silicon bronze 2.75-3.25 Si/0.75-1.25 Mn/Bal Cu C9

4.5-6.0 Sn/0.02-0.4 P/Bal Cu C103. Tin bronzes

6.0-7.5 Sn/0.02-0.4 P/Bal Cu C11

6.0-7.5 AI/Bal Cu C12 May contain 1.0-2.5Fe+Ni+Mn

6.5-8.5 AI/2.5-3.5 Fe/Bal Cu C12Fe

9.0-11.0 Al/0.75-1.5 Fe/Bal Cu C13

8.0-9.5 Al/1.5-3.5 Fe/3.5-5.0 Ni/Bal Cu C20

4. Aluminium bronze

7.0-8.5 AI/2.0-4.0 Fe/1.5-3.0 Ni/11.0-14.0 Mn/Bal Cu C22

5. Brasses None available to BS 2901 May contain 1.0-2.5Fe+Ni+Mn

Note: Brasses not normally welded with matching filler alloy owing to zinc fuming. Aluminium bronze fillers C12and C12 Fe are preferred.

10.0-12.0 Ni/0.2-0.5 Ti/0.5-1.0 Mn/1.5-1.8 Fe/Bal Cu C166. Cupro nickels

30.0-32.0 Ni/0.2-0.5 Ti/0.5-1.5 Mn/0.4-1.0 Fe/Bal Cu C18

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British Standard specificationsThe following British Standards referred to in the text of this technical note are obtainable fromthe British Standards Institution

BS 219:1959 Soft solders.

BS 864 Part 2:1971. Capillary and compression fittings of copper and copperalloy complying with BS 2871 :Part 1 Table X, TableY and Table Z.Metric units.

BS 1400:1969 Copper alloy ingots and copper and copper alloy castings. Metric units.

BS 1845:1966 Filler metals for brazing.

BS 2051 Tube and pipe fittings for engineering purposes.Part 1:1953. Copper and copper alloy capillary and compression tubefittings (for use with fractional o.d. sizes of tubes).Part 2:1954. Olive, soldered nipple and flared types of copper andcopper alloy tubefittings (for use with fractional o.d. sizes of tubes).

BS 2870:1968 Rolled copper and copper alloys, sheet, strip and foil. Metric units.

BS 2871 Copper and copper alloy tubes. Metric units.Part 1:1971. Copper tubes for water, gas and sanitation.Part 2:1972. Tubes for general purposes.Part 3:1972. Tubes for heat exchangers.

BS2872:1969 Copper and copper alloys. Forging stock and forgings. Metric units.

BS2873:1969 Copper and copper alloys. Wire. Metric units.

BS2874:1969 Copper and copper alloys. Rod and sections (other than forging stock).Metric units.

BS 2875:1969 Copper and copper alloys. Plate. Metric units.

BS 2901 Filler rods and wires for gas-shielded arc welding. Metric units.Part 3:1970. Copper and copper alloys

BS 3274:1960 Tubular heat exchangers for general purposes.

BS4504:1969 Flanges and bolting for pipes, valves and fittings. Metric series.

BS4580:1970 Number designation of organic refrigerants.

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Tables of Material PropertiesTable A - British Standard designations and chemical compositions of copper alloys – wrought forms

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Table B - British Standard designations and chemical compositions of copper alloys - cast forms

17

Table C - Mechanical and physical properties of copper alloys - wrought forms – at 20oC

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Table D – Mechanical and physical properties of copper alloys – wrought forms – (at 20oC)