29 Cu 63.546

Copper

An in depth guide

metals4U stock electrical grade C101 copper and the non-electrical C106 grade in a selection of profiles suitable for a wide range of projects and applications.

Uses

Copper is well suited to the manufacture of a wide range of applications such as electric cabling, pipes, general engineering, wiring, circuit boards, roofing, fermentation vessels, saucepans, heat exchangers, car and vehicle radiators, heat sink components, fasteners, transformers, general electronics, busbars, motor components, building fascias, heat sinks, cable strips, storage tanks, plumbing pipes and fittings, refrigeration applications, and gas plants.

The forms we supply

Sheet, flat bar, round bar, tubes, and fitting for plumbing applications.

Overview

Copper is the oldest metal used by mankind and dates to pre-historic times. Copper is found as a ‘native’ metal, which simply means that it is a metal that is found in its pure metallic form and needs no further extraction; it is also found within minerals such as cuprite, malachite, chalcopyrite, and bornite; it is also a by-product of silver production. Tin is added to copper to produce bronze and zinc is added to copper to make brass; copper is also often added to aluminium alloys to improve strength and to Corten steel to increase corrosion resistance and strength.

Copper is constructed of a face centred cubic crystal structure (FCC) and polishes to a bright metallic yellow / red / gold lustre; this makes it easily distinguishable from most other commercially used metals.

Native copper has been mined for over 10000 years. The earliest discovery of the use of copper wasin Iraq in the form of a copper pendant dating back to around 8700 BCE, copper was also mined between 6000 and 3000 BCE during a period of history referred to as the ‘old copper complex’ era. Native American civilisations found copper nuggets in the gravel beds and in veins around the Great Lakes of North America. The native Americans used the pure copper to make weapons, tools and decorative items. Copper was much more useful than gold to these early civilisations as it is much stronger so more suited to making weapons, fishhooks, knife blades, spear heads for hunting, and woodworking tools. By 5000BCE copper was also being smelted from simple copper oxides making it stronger, and more versatile.

Second only to silver, copper is an excellent thermal and electrical conductor. Copper was the material traditionally used for overhead power cables, however, its weight means that it is no longer widely used. Cheaper and lighter aluminium is now widely used as it has almost twice the electrical conductivity of copper by weight, however, its lack of strength means that each aluminium cable strand has to be reinforced with aluminium coated, or galvanised, high tensile steel wire.

Welding guide

Welding copper to Filler wire/ welding consumables most commonly used.
Copper pipes C106 Sifsilcopper 985, Sifsilcopper no 7HQ, sifcupron no 17-2ag, sifsilcopper flux
Copper Sifsilcopper no 7HQ, hilco Bronsil, sifmig 985,TIG sifsilcopper no 7, sifsilcopper 985, sifcupron no 17,sifsilcopper flux
mild steel Sifphosphor Bronze no 8, sifmig no 8, sifmbronze no 1 with sifbronze flux, silver solder rod & flux
Brass Sifphosphor Bronze no 8 with pure argon shielding gas, sifmig 8. Sifsilbronze 101, sif silver solder
Aluminium Hilco aluminium si 12
Albronze Sifalbronze no 32, Sifmig 328
Stainless steel grades 304 & 316 Sifphosphor bronze no 8, 316, 309, sifmig 8, Sif silcopper 968, sifbronze no 2 rod, sif silvercote no 43,
bronze Sifphosphor bronze no 8 & Sifsilcopper flux.

The grades of copper

The physical properties of copper place its conductivity at twice that of aluminium and thirty times that of stainless steel when not factoring weight considerations. This means that copper is an excellent choice for applications and components where rapid heat transfer is essential; saucepans, heat exchangers, car and vehicle radiators, and heat sinks components in computers, disk drives, and TV sets for example.

The strength, conductivity, corrosion resistance, machinability and ductility of copper make it one of the most versatile engineering materials available. Up to 47% of annual copper production is used in the building and construction industry for electrical wiring, roofing, cladding, rainwater systems, heating systems, water pipes, and oil and gas lines; a further 23% is utilised within the electronics industry. There are around 370 commercial copper alloy designations with C106 being the most common with over 18M tonnes consumed each year.

Unlike many other metals, the yield strength of copper cannot be easily defined. The most uniform way to work it out is as 0.5% extension under load or as 0.2% offset. Usually the 0.5% extension yield strength of annealed copper is around 1/3 of the tensile strength. As copper is hardened during cold working, it becomes less ductile and the yield strength becomes closer to the tensile strength.

Corrosion resistance

Copper has excellent corrosion resistance properties in most rural, marine, and industrial environments and is resistant to saline solutions, soils, non-oxidising materials, organic acids and caustic solutions. Copper develops a surface oxidation layer with a distinctive green/ blue patina that protects the copper from further oxidation and corrosion. The surface patination of copper can be halted by applying a lacquer to protect the surface and to retain the original colour of the base metal. Acrylic coatings that contain benzotriazole will ensure the patination is stalled for many years in an external, abrasion free environment.

Copper is often used on building projects, usually for roofing and architectural features, as the blue / green patina, or Verdigris, is utilised for a distinctive and striking effect.

Copper is prone to corrosion from moist ammonia environments, halogens, sulphides, inorganic acids and solutions containing ammonia ions, and oxidising acids such as nitric acid. It is recommended that for under soil use, where contamination of soil may be present or occur in future, that copper pipes are laid within plastic pipes to protect from any undetected corrosive substances.

Recycling

Copper is 100% recyclable without losing any of its physical or chemical properties; because of this, copper retains its high value within the scrap market.

Antimicrobial

Copper is a naturally hygienic metal which slows down the growth of harmful germs such as E. coli, MRSA and legionella within just 1-2 hours of contact; this is an intrinsic property that does weaken with time. Copper also has good biofouling properties.

Copper’s ease of shaping, corrosion resistance, antimicrobial and biofouling resistance properties make it ideal for use in the construction and use of brewing vessels.

An additional benefit of copper is its usefulness to repel slugs. The positively charged ions in copper react with the water and protein-based slime that covers slugs and snails, this causes an unpleasant electro-neural effect that is similar to an electric shock- don’t worry though, this does not harm them.

The grades of copper

Here is a guide to each copper grade to help you choose which is best for your project.

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Grade C106

Grade C106 is a phosphorus deoxidised non-arsenical grade that has had the oxygen removed from the metal by the controlled addition of phosphorus during the melting cycle, it has a minimum Copper content of 99.85%. This grade is also referred to as CW024A or Cu-DHP. This grade has good electrical and thermal conductivity, excellent formability and is not susceptible to hydrogen embrittlement (HE), which is caused when molten metal becomes saturated with hydrogen immediately after solidification- this can lead to a decrease in toughness and ductility.

C106 is the most commonly used of all copper grades and is utilised for non-electrical applications, general engineering, fasteners, construction, connectors, transformers, general electronics, busbars, motor components, building fascias, heat sinks, cable strips, storage tanks, plumbing pipes and fittings, refrigeration applications and gas plants.

  • Non-electrical
  • General engineering
  • Fasteners
  • Construction
  • Connectors
  • Transformers
  • General electronics
  • Busbars
  • Motor components

Properties

Physical Property Value
Density 892 Kg/m3
Melting Point 1083 °C
Modulus of Elasticity 117 GPa
Electrical Resistivity 0.0171 µΩm
Electrical Conductivity 100 IACS
Thermal Conductivity 391.1 W/m.K
Thermal Expansion 16.9 µm/m-k
Mechanical Property Value
Yield Strength -
Tensile Strength 200-400 N/mm²
Proof Stress 0.2% 50-340 N/mm²
Shear Strength -
Hardness 40-120 Vickers - HV
Elongation (in 200mm) 5-50%

The chemical composition (% weight)

Copper Phosphorus
99.9 0.015-0.040

Machinability

C106 grade copper has poor machinability- it is rated as 20% when compared to CZ121, the 100% free cutting brass grade used for allocating machinability ratings of metals.

Formability

C106 has excellent formability.

Hot working

Grade C106 has a good formability rating for hot working, the recommended temperature range is between 760°C and 950°C.

Cold Working

Excellent results are achieved when cold working. C106 has a rating of 70% bendability, compared to the standard set using gilding brass (95%).

Ductility

This grade has excellent ductility. C106 will work harden, particularly during cold working processes, however, ductility can be easily restored by performing a specific anneal cycle or through incidental annealing when welding, soldering, or brazing.

Cutting

Copper can be cut using a hacksaw, tube cutter, shears, angle grinders, bench saws and flame cutting techniques. Copper can be drilled with hand and mechanical methods.

It is recommended to wear PPE gloves and eye protection when cutting copper as the cut edge can be very sharp.

Welding

Excellent results are achieved with gas shielded arc welding, soldering and brazing.

Oxy Acetylene and resistance butt welding give good results.

Spot, and seam welding give ‘fair’ results, therefore, these are not recommended for this grade of copper.

Annealing

Solution treating, or annealing, can be achieved by heating the work piece to between 370° C and 650°C followed by a rapid cool cycle. The cold reduction between anneals is maximum 95%.

Hardening

C106 copper will work harden, especially when cold worked.

Tempering

This grade of copper is supplied in half hard temper conforming to BS EN 1652: 1998. This temper is also achieved by process cold working and subsequent annealing cycles. Annealing could be from a targeted anneal cycle or incidental annealing from welding and soldering.

Corrosion resistance

Copper has good corrosion resistance within most atmospheric conditions, including industrial and marine environments. C106 is susceptible to being corroded by oxidising acids, halogens, sulphides and solutions containing ammonia.

Forging

The hot forgeability of C106 is rated as 65 (compared to forging brass rated as 100) with a recommended hot forging temperature of between 760°C and 870°C.

Brazing

C106 delivers excellent results when brazed.

Soldering

Soldering for this grade of copper is defined as ‘excellent’.

Process Rating
Workability - Cold Excellent
Workability - Hot Good
Machinability Poor
Gas Shielded Arc Excellent
Oxyacetylene Good
Process Rating
Resistance / Butt Good
Spot Not recommended
Seam Not recommended
Brazability Excellent
Solderability Excellent (soft and hard)

Supply

C106 is available in a range of sheet sizes and thicknesses. All our copper sheet stock conforms to BS EN 1652:1998 and is supplied in H02, (half hard) temper. We also stock and supply the following pipes and fittings for plumbing applications;

Tube: a wide selection of diameters is available and are supplied in standard 3000mm lengths or can be custom cut to your requirements. All our tube is from a reputable source and complies with BS EN 1047.

End feed fittings: Coupling, elbow, equal T, 45° reducing coupling and reducing T. These conform to BS EN 1254-1:1998

Solder ring fittings: 90° elbow, coupling and equal T. These are similar to our standard end fittings but have a ring of lead-free solder pre-applied at each end- this simply requires heating to join to copper tube. These plumbing supplies all conform to BS EN 1057 and are supplied in H02 half hard temper

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Grade C101

C101 in an electrical grade copper that is commonly also referred to as high conductivity Copper, Cu-ETP, or CW004A. This grade is excellent for use in electrical applications due to its high thermal conductivity; C101 has a classification of 100% IACS (International Annealed Copper Standard) This is an industry derived standard for the electrical conductivity of commercially supplied copper.

C101 is a hard drawn, high conductivity copper that is the most commonly used base copper to produce common brass and bronzes.

C101 is refined during manufacture by electrolytic disposition, then heated to melting point and oxidised to a ‘tough pitch’ condition to produce a low oxygen content. This ETP copper is the highest purity tough pitch copper suitable for the most challenging electrical applications such as those involving the transmission of electrical signals and power, cable strips, transformers, general electronics, connectors, busbars, motor components, building fascias and heatsinks.

  • Signals and power
  • Cable strips
  • Transformer
  • General electronics
  • Connectors
  • Busbars
  • Motor components
  • Building fascias
  • Heatsink

Properties

Physical Property Value
Density 892 Kg/m3
Melting Point 1083 °C
Modulus of Elasticity 117 GPa
Electrical Resistivity 0.0171 µΩm
Electrical Conductivity 100 IACS
Thermal Conductivity 391.1 W/m.K
Thermal Conductivity 391.1 W/m.K
Thermal Expansion 16.9 µm/m-k
Mechanical Property Value
Yield Strength -
Tensile Strength 200-400 N/mm²
Proof Stress 0.2% 50-340 N/mm²
Shear Strength -
Hardness 40-120 Vickers - HV
Elongation (in 200mm) 5-50%

The chemical composition (% weight)

Copper Phosphorus
99.9 0.015-0.040

Machinability

C101 has poor machinability. It has a rating of 20% compared to the CZ121 free machining brass that is used as the 100% standard for comparison.

Formability

This grade has good to excellent formability.

Hot working

This copper grade has good formability when hot worked. The optimum hot working temperature is 750°C to 950°C.

Cold working

Cold formability is rated as excellent and can be readily bent into shape with appropriate hand tools.

Ductility

The ductility is C101 is rated as high or excellent.

Welding

C101 is prone to hydrogen embrittlement when welding or brazing using an oxy-fuel gas flame due to the presence of oxygen in the gasses used. Oxy Acetylene welding is not suitable for use on this grade.

Excellent results are achievable when joining by electric arc methods such as flux cored arc welding and soldering.

Resistance welding techniques such as spot and seam welding are not recommended. Butt welding is only rated as good, and gas shielded arc welding such as TIG and GTAW as fair.

Annealing

C101 will work harden and will require either a dedicated anneal cycle during working or an incidental cycle via welding or brazing as part of the working process. Annealing temperature is recommended at between 350°C to 650°C followed by a rapid cool cycle. A stress relieve cycle can be completed at 150°C to 200°C.

The maximum cold reduction between anneal cycles is 90% maximum.

Hardening

Cu ETP or C101 will work harden, however, it cannot be hardened by heat treatments.

Tempering

Our C101 grade stock is supplied as half hard (H02) designation.

Corrosion resistance

All grades of copper have very good to excellent corrosion resistance in most environments. C101 is susceptible to the effects of corrosion if used in environments that contain halogens, sulphides and solutions containing ammonia, and oxidising acids.

Forging

Excellent results are achieved with cold forging and annealing as necessary as the piece work hardens.

Many metal workers prefer to hot forge copper as hot forging enables the craftsperson to create shapes that could not be created by cold forging- such as more ‘fluid’ shapes for example. When hot forging, it is important to be mindful that due to the excellent thermal conductivity of C101 there is no ‘cold end’ as there may be with other metals, therefore, appropriate PPE should be used.

Casting

This grade of high conductivity copper is suitable for die and sand castings, particularly for the manufacture of electrode holders and electrical switch gear – castings may be slightly lower on the conductivity index; however, this will still be a minimum rating of 93% IACS.

Brazing

Good results are achieved with brazing.

Process Rating
Workability - Hot Good
Workability - Cold Excellent
Machinability Poor
Oxy Acetylene Not suitable
Electric Arc Excellent
Process Rating
Gas Shielded Arc Fair
Resistance Not recommended.
Butt Welding Good
Brazability Good
Solderability Excellent

Supply

C101 is available in a wide range of widths and lengths of flat bar and round bar profiles. These products are supplied in a H02 (half hard) temper and mill finish.

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