Standards are important because they form a common language between producers, stockists and users of copper alloys. It is important to have the facility to compare the old British, European, American and Japanese Standards. CDA provides the information to enable users to do this, through publications and its online enquiry service.
UK and European Standards
Copper and copper alloys like other materials are covered by standards. The use of standards is essential in the proper definition of the type, form and condition of an alloy. Standards form part of the complex technical language used in communication between producers of alloys, manufacturers, designers and stockists and any technical person concerned with materials usage. It is not sufficient to define an alloy as 'brass' or 'bronze' just as a steel would not be defined as 'stainless' or 'low alloy'. For many years copper alloys have been covered by British Standards. These have been being replaced by European BS EN Standards which will include other National Standards such as DIN (German).
American Standards
Americans are not usually familiar with British or European Standards. They use the UNS (Unified Numbering System) which is the accepted alloy designation system in North America for wrought and cast copper and copper alloy products - it is managed by ASTM and SAE. When manufacturing for USA. it is essential to find a UK or European Standard which is equivalent to an existing American Standard. See Copper Key.
An incorrectly defined material may in the end only be fit for scrap.
The following text is the introduction to Publication 120 'Copper and Copper Alloys - Standards, Specifications and Applications'.
To access the individual data tables or to order the publication, click here.
The EN Standards
The EN series of standards for copper and copper alloys offers a selection of materials to suit a very wide variety of end uses. They represent a consensus agreement on those most frequently ordered by consumers. Commencing in the late 1980s, drafting of European Standards for Copper and Copper Alloys became a major activity for national standards’ organisations and their industrial partners. Because a large number of national preferences have needed to be taken into account against the background of a pan- European agreement to develop tight product standards, the EN standards are more complex than the old BS standards. Furthermore, the EN standards tend to cover narrower fields than BS standards; hence there are more alloys in the EN series than in the old BS standards.
This publication summarises the main compositions and the range of properties. For full details refer to the standards documents obtainable from:
The British Standards Institution
398 Chiswick High Road
London W4 4AL
Tel: 020 8996 9001
Fax: 020 8996 7001
Web: www.bsi-global.com
Numbers and Titles of Standards
Table 1 shows EN standards’ titles, categorised by product type, and the BS standards that have been replaced. During the standardisation process, at the stage of draft for public comment, an EN number is allocated. At this stage drafts are identified with the prefix ‘pr’. After successful formal vote, when the draft is approved for publication throughout Europe, the EN implementation uses the same number.
Table 2 shows old BS standard numbers in numerical order and their replacement EN standards.
Product Forms
As part of the standardisation process, uniform definitions have now been adopted for all product forms. This will result in some products having new terminology. As an example, the term ‘wire’ now includes all material made in coil form.
Material Designations
Material designations (individual copper and copper alloy identifications) are in two forms, symbol and number. As with many other existing European national standards, symbols are based on the ISO compositional system (e.g. CuZn37 is 63/37 brass). ISO and EN symbols may be identical but the detailed compositional limits are not always identical and cannot be assumed to refer to unique materials.
Numbering System
A new numbering system has therefore been developed to offer a more user- and computer-friendly alternative. The system is a 6-character, alpha-numeric series, beginning C for copper based material; the second letter indicates the product form as follows:
- B – Materials in ingot form for re-melting to produce cast products
- C – Materials in the form of cast products
- F – Filler materials for brazing and welding
- M – Master alloys
- R – Refined unwrought copper
- S – Materials in the form of scrap
- W – Materials in the form of wrought products
- X – Non-standardised materials
A three-digit number series in the 3rd, 4th and 5th places is used to designate each material and can range from 001 to 999. Numbers are allocated in preferred groups, each series being shown below. The sixth character, a letter, indicates the copper or alloy grouping as follows:
Number series |
Letters |
Materials |
000-099 |
A or B |
Copper |
100-199 |
C or D |
Copper alloys, low alloyed (less than 5% alloying elements) |
200-299 |
E or F |
Miscellaneous copper alloys (5% or more alloying elements) |
300-349 |
G |
Copper–aluminium alloys |
350-399 |
H |
Copper–nickel alloys |
400-449 |
J |
Copper–nickel–zinc alloys |
450-499 |
K |
Copper–tin alloys |
500-599 |
L or M |
Copper–zinc alloys, binary |
600-699 |
N or P |
Copper–zinc–lead alloys |
700-799 |
R or S |
Copper–zinc alloys, complex |
Symbol Designations
The symbols used are based on the ISO designation system (ISO 1191 Pt1).
- The principal element, copper, is first.
- Other alloying elements are included in decreasing order of percentage content.
- Where contents are similar, alphabetical order may be used.
- The numbers after elements represent nominal compositions.
- No number is normally used if the nominal composition is less than 1%.
Material Condition (Temper) Designations
Material condition (alternative term – temper) designations are defined in EN 1173. In most product standards, materials are available in a choice of material conditions. Depending on the product standard there may be one or more mandatory properties associated with the particular material condition. For designation purposes the principal mandatory property for each material condition is identified by a letter, as follows:
- A – Elongation
- B – Spring bending limit
- D – As drawn, without specified mechanical properties
- G – Grain size
- H – Hardness (Brinell or Vickers)
- M – As manufactured, without specified mechanical properties
- R – Tensile strength
- Y – 0.2% proof strength
Products can only be ordered to one material condition and not a combination. However, besides the designating property, other properties may be mandatory; check the standard document for full details. Normally three digits, but in a few instances four digits, follow the material condition designating letter, where appropriate, to indicate the value of the mandatory property with the possibility of a final character, ‘S’, for the stress relieved condition. Normally the value refers to a minimum for the property. Sometimes, as with grain size, it refers to a nominal mid-range value. Tables 6 to 12 show not only the existence of copper or copper alloys in particular standards but also the material conditions available as mandatory properties within those standards.
Castings
For castings, properties are dependent on the casting process used. This is designated according to the system:
- GS sand casting
- GM permanent mould casting
- GZ centrifugal casting
- GC continuous casting
- GP pressure diecasting.
Examples
CW614N–R420 refers to:
Wrought CuZn39Pb3 copper-zinc-lead alloy to be supplied to a minimum tensile strength of 420 N/mm2
CC750S-GS refers to:
Sand cast CuZn33Pb2 copper-zinc duplex alloy.
Ordering Information
Each product standard gives examples of the full ordering information required including quantity, product form, standard number, designation, condition, tolerances and packaging.
Typical Properties
In Tables 6 to 12, typical properties are usually shown as ranges. For materials available in both ‘soft’ condition, for example as forging stock, and ‘very hard’, for example as spring wire, then the ranges are very wide. Tables 14 to 18 show typical properties for ranges of brasses similar to those previously included in British Standards in order to give a closer idea of the range of properties available in each product form.
It is vital that designers and purchasers consult with suppliers to clarify what property values and combinations are available to be best fit for purpose in the desired product form.
Declarations of Conformity
Where the full quality systems standardised in EN ISO 9001 series of standards are not required, a declaration of conformity may still be needed to confirm compliance with order requirements: In EN 1655 ‘Copper and Copper Alloys – Declarations of Conformity’, four levels of declaration of conformity are available:
- Type A for suppliers who do not have a certified quality assurance scheme.
- Type B for suppliers who do not have a certified quality assurance scheme but have access to an accredited laboratory.
- Type C for suppliers who have a certified quality assurance scheme but do not have access to an accredited laboratory.
- Type D for suppliers who have both a certified quality assurance scheme and access to an assessed laboratory.
These declarations are more specific than those based on systems used for steels included in EN 10204 ‘Metallic Products – Types of Inspection Documents’.
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