Copper

Copper has the highest electrical conductivity of any metal except silver and when alloyed retains its high ductility as well as developing the ability to be easily joined and machined and being capable of achieving high strengths by heat treament.

High Conductivity Copper

The grades of copper used for electrical applications such as busbars, cables and windings require the highest electrical conductivity and are at least 99.9% pure. The grades are Cu-ETP (CW004A) which has 0.02%-0.04% oxygen and Cu-OF(CW008A) which is oxygen free. High conductivity copper has excellent ductility which means that it can be easily drawn to fine wire sizes and is available in all fabricated forms.

For detailed information on properties and applications, see Pub 122.

Phosphorised Deoxidised Copper

This grade can be readily brazed or welded without fear of embrittlement. It is used for plumbing tube, hot water cylinders and roofing sheet.

The grade used is CW024A.

Free Machining Copper

An addition of approximately 0.5% tellurium or sulphur raises the machinability rating from 20% to 90%, based on a scale where free machining brass is rated at 100%. The particles of copper telluride or copper sulphide act as chip breakers leading to excellent machinability without substantially affecting the electrical conductivity which is rated at 93% IACS. Free machining copper is used where a large amount of repetitive machining at high rates is required. One example is in the production of gas cutting nozzles which involves the drilling of small holes in rods followed by swaging to the finished shape. Other applications include screws, fasteners, contacts, connectors, clamps and bolts.

Heat Treatable Copper Chromium and Copper Chromium Zirconium (CuCr and CUCrZr)

Copper chromium and copper chromium zirconium are heat treated by precipitation hardening to give a typical tensile strength of 450 Mn/m² with 10% elongation. They have a good electrical conductivity of 80% IACS. This makes them ideal for heavy duty electrical busbars and switchgear when a guaranteed long, maintenance-free life is required. Similarly, spot and seam resistance welding electrodes which require strength at temperature (up to 400°C) are made from these alloys.

Copper Beryllium (CuBe)

The highest strength of ANY copper alloy (typically 1300 MN/m², with 4-5% elongation) is obtained by precipitation hardening and cold working copper beryllium (0.4-2.0%). The high strength, together with non- magnetic and non-sparking properties plus good corrosion resistance, lead to applications for tooling used in oil and gas exploration. The high elastic limit and good fatigue resistance make CuBe alloys an ideal choice for springs and connectors for military and domestic applications. They have long been used for non- sparking tools in hazardous applications. Health and Safety precautions must be taken when beryllium fume is produced during melting or welding operations.

Publications and Software

To see all publications and software click here.

TN 23 Copper for Contacts
Copper is present in nearly all electrical contact applications, either in the material of the contacts themselves, as a backing material, or in the construction of the contact carrier connections and terminals of the switch contact assembly. This publication looks at the properties required for contact materials, and to identify those applications in which copper or copper alloys have special advantages.

Publications Pub 44 Machining Brass, Copper and its Alloys
Detailed advice on machining techniques. Guide to choice of speeds and feeds. Comprehensive list of British and European alloys with details of machinability. Advice on the selection of cutting fluids. 1992. 66pp.

Publications Pub 54 Beryllium Copper
This booklet focuses on the properties, applications and practical manipulation of copper beryllium and covers precipitation hardening, to which beryllium copper owes its high strength and hardness. 1996. 50pp.

Pub 98 Joining of Copper and Copper Alloys
Suitability of the many methods now available for the jointing of copper and copper alloys with details of filler materials and recommendations for good joining practice. 1994. 44pp.

Pub 104 Copper-Beryllium Health and Safety Notes
Guidance notes for users of copper beryllium products. 1994. 3pp.

Pub 122 High Conductivity Coppers for Electrical Engineering
This booklet describes the way in which coppers of all types have been developed and improved to meet the design requirements of electrical engineers. The materials described are the commercially pure coppers, low alloy coppers and the copper alloys with good elevated temperature properties used for special purposes. Revision of publication 29 with BS EN standards and the old BS equivalents given. 1998 40pp.

TN 27 High Conductivity Coppers for Electrical Engineering
These data sheets, prepared by the International Copper Development Council (CIDEC), were originally published in a series during the period 1968 - 1972 and cover all the main coppers and copper alloys. They contain an invaluable summary of data relating to the physical and mechanical properties of the materials at low, ambient and elevated temperatures which is not available elsewhere. Tensile, hardness, impact, creep and fatigue data have been abstracted from the relevant original literature.