Beryllium copper
Encyclopedia
Beryllium copper also known as copper beryllium, beryllium bronze and spring copper, is a copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

 with 0.5—3% beryllium
Beryllium
Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...

 and sometimes with other alloying elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has excellent metalworking
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...

, forming and machining qualities. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and aerospace. Beryllium-containing alloys create an inhalation hazard during manufacturing due to their toxic properties.

Properties

Beryllium copper is a ductile, weldable, and machinable alloy. It is resistant to non-oxidizing acids
Oxidizing acid
An oxidizing acid is a Brønsted acid that is also a strong oxidizing agent . All Brønsted acids can act as moderately strong oxidizing agents, because the acidic proton can be reduced to hydrogen gas. Some acids contain other structures that act as stronger oxidizing agents than hydrogen....

 (for example, hydrochloric acid, or carbonic acid), to plastic decomposition products, to abrasive
Abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away...

 wear
Wear
In materials science, wear is erosion or sideways displacement of material from its "derivative" and original position on a solid surface performed by the action of another surface....

 and to galling
Galling
Galling usually refers to the adhesive wear and transfer of material between metallic surfaces in relative converging contact during sheet metal forming and other industrial operations....

. Furthermore, it can be heat-treated
Heat treatment
Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass...

 to improve its strength, durability, and electrical conductivity. Beryllium copper attains the highest strength (to 1400 MPa (203,052.8 psi)) of any copper-based alloy.

As beryllium compounds are toxic, there are some safety concerns with handling its alloys. In solid form and as finished parts, beryllium copper presents no known health hazard. However, breathing its dust or vapors, as formed when machining or welding, may cause serious lung damage. Beryllium compounds are known human carcinogens when inhaled. As a result, beryllium copper is sometimes replaced by safer copper alloys such as Cu-Ni-Sn bronze.

Uses

Beryllium copper is a non-ferrous
Non-ferrous metal
In metallurgy, a non-ferrous metal is a metal that is not ferrous, that is, any metal, including alloys, that does not contain iron in appreciable amounts...

 alloy used in springs
Spring (device)
A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...

, spring wire, load cell
Load cell
A load cell is a transducer that is used to convert a force into electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation as an electrical signal, because the...

s and other parts that must retain their shapes during periods in which they are subjected to repeated stress and strain. Due to its electrical conductivity, it is used in low-current contacts for batteries and electrical connectors.

Because beryllium copper is non-sparking
Spark (fire)
A spark is an incandescent particle. Such sparks may be produced by pyrotechnics, by metalworking or as a by-product of fires, especially when burning wood.-Pyrotechnics:...

 but physically tough and nonmagnetic, it is used to make tools that can safely be used in environments where there are explosive vapors and gases, such as on oil rig
Oil rig
Oil rig may refer to* Drilling rig, an apparatus for on-land oil drilling* Oil platform, an apparatus for offshore oil drillingOIL RIG or OILRIG may refer to :...

s. Beryllium copper fulfills the demands of ATEX directive
ATEX directive
The ATEX directive consists of two EU directives describing what equipment and work environment is allowed in an environment with an explosive atmosphere...

 for use in Zone 0, 1, and 2. Various tool types are available, including screwdriver
Screwdriver
A screwdriver is a tool for driving screws and often rotating other machine elements with the mating drive system. The screwdriver is made up of a head or tip, which engages with a screw, a mechanism to apply torque by rotating the tip, and some way to position and support the screwdriver...

s, pliers
Pliers
Pliers are a hand tool used to hold objects firmly, for bending, or physical compression. Generally, pliers consist of a pair of metal first-class levers joined at a fulcrum positioned closer to one end of the levers, creating short jaws on one side of the fulcrum, and longer handles on the other...

, spanners, cold chisels and hammers. An alternative metal sometimes used for non-sparking tools is aluminum bronze. Compared to tools made of steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

, beryllium copper tools are more expensive, are not as strong, and wear out more quickly. However, the advantages of using beryllium copper in hazardous explosive environments outweigh these disadvantages.

Beryllium copper is frequently used in the manufacture of professional-quality percussion instruments, especially tambourine
Tambourine
The tambourine or marine is a musical instrument of the percussion family consisting of a frame, often of wood or plastic, with pairs of small metal jingles, called "zils". Classically the term tambourine denotes an instrument with a drumhead, though some variants may not have a head at all....

 and triangle, where it is prized for its clear tone and strong resonance. Unlike most other materials, an instrument composed of beryllium copper will maintain a consistent tone and timbre for as long as the material resonates. The "feel" of such instruments is rich and melodious to the point that they seem out of place when used in darker, more rhythmic pieces of classical music.

Beryllium copper has found use in ultra-low temperature cryogenic equipment, such as dilution refrigerator
Dilution refrigerator
A dilution refrigerator is a cryogenic device first proposed by Heinz London. Its refrigeration process uses a mixture of two isotopes of helium: helium-3 and helium-4...

s, because of its combination of mechanical strength and relatively high thermal conductivity in this temperature range.

Beryllium copper has been used for armour piercing bullet
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...

s, though any such usage is unusual because bullets made from steel alloys are much less expensive, but have similar properties.

Beryllium copper is used for measurement-while-drilling tools in the directional (slant drilling) drilling industry. A non-magnetic alloy is required, as magnetometers are used for field-strength data received from the tool.

Beryllium copper gaskets are used to create an RF-tight (resistant to radio frequency leakage), electronic seal on doors used with EMC
Electromagnetic compatibility
Electromagnetic compatibility is the branch of electrical sciences which studies the unintentional generation, propagation and reception of electromagnetic energy with reference to the unwanted effects that such energy may induce...

 testing and anechoic chamber
Anechoic chamber
An anechoic chamber is a room designed to stop reflections of either sound or electromagnetic waves.They are also insulated from exterior sources of noise...

s.

For a time, beryllium copper was used in the manufacture of golf clubs
Golf club (equipment)
A golf club is used to hit a golf ball in a game of golf. Each club is composed of a shaft with a grip and a clubhead. Woods are mainly used for long-distance fairway or tee shots; irons, the most versatile class, are used for a variety of shots; Hybrids that combine design elements of woods and...

, with emphasis on wedges and putters. Many golfers prefer the soft feel of BeCu club heads, particularly for chip shots and putts around and on the green, where an extra measure of control is desired. Due to regulatory issues and high costs, BeCu clubs are difficult to find in current production, so vintage and pre-owned examples remain in demand.

Alloys

Alloy 25 beryllium copper (C17200 & C17300) is an age-hardening alloy which attains the highest strength of any copper base alloy. It may be age hardened after forming into springs, intricate forms or complex shapes. It has superb spring properties, corrosion resistance and stability as well as good conductivity and low creep.

Tempered beryllium copper is Alloy 25 (C17200 & C17300) which has been age hardened and cold drawn. No further heat treatment is necessary except for a possible light stress relief. It is sufficiently ductile to wind on its own diameter and can be formed into springs and most shapes. Tempered wire is most useful where the properties of beryllium copper are desired, but age hardening of finished parts is not practical.

Alloys 3 (C17510) and 10 (C17500) beryllium copper are age-hardenable and provide excellent electrical conductivity in combination with good physical properties and endurance strength. Provided in either the age-hardenable condition or as tempered ware, they are used in springs and wire forms which are electrical conductors, or where retention of properties at elevated temperatures is important.

High strength beryllium copper alloys contain up to 2.7% of beryllium (cast), or 1.6-2% of beryllium with about 0.3% cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

 (wrought). The high mechanical strength is achieved by precipitation hardening or age hardening. The thermal conductivity of these alloys lies between steels and aluminium. The cast alloys are frequently used as material for injection molds. The wrought alloys are designated by UNS
Unified numbering system
The unified numbering system is an alloy designation system widely accepted in North America. It consists of a prefix letter and five digits designating a material composition. A prefix of S indicates stainless steel alloys, C for copper, brass, or bronze alloys, T for tool steels, etc...

 as C17200 to C17400, the cast alloys are C82000 to C82800. The hardening process requires rapid cooling of the annealed metal, resulting in a solid state solution of beryllium in copper, which is then kept at 200-460 °C for at least an hour, facilitating precipitation of metastable beryllide
Beryllide
Beryllide is an intermetallic compound of beryllium with other metals, e.g. zirconium, tantalum, titanium, nickel, or cobalt.Beryllides of cobalt and nickel have metallurgical importance as the precipitated phase in beryllium copper alloys....

crystals in the copper matrix. Overaging is avoided, as an equilibrium phase forms that depletes the beryllide crystals and reduces the strength enhancement. The beryllides are similar in both cast and wrought alloys.

High conductivity beryllium copper alloys contain up to 0.7% beryllium, together with some nickel and cobalt. Their thermal conductivity is better than of aluminium, only a bit less than pure copper. They are usually used as electric contacts in connectors.

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