
Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze, and spring copper, is a
copper alloy with 0.5–3%
beryllium
Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with ...
. Copper beryllium alloys are often used because of their high strength and good conductivity of both heat and electricity. It is used for its
ductility
Ductility refers to the ability of a material to sustain significant plastic Deformation (engineering), deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic def ...
,
weldability in
metalworking
Metalworking is the process of shaping and reshaping metals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on e ...
, and machining properties. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and some uses in the field of
aerospace
Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astron ...
. Beryllium copper and other beryllium alloys are harmful carcinogens that present a toxic inhalation hazard during manufacturing.
Properties
Beryllium copper is a
ductile
Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversi ...
, weldable, and machinable alloy. Like pure copper, it is resistant to
non-oxidizing acids (such as
hydrochloric acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...
and
carbonic acid
Carbonic acid is a chemical compound with the chemical formula . The molecule rapidly converts to water and carbon dioxide in the presence of water. However, in the absence of water, it is quite stable at room temperature. The interconversion ...
) and plastic decomposition products, to
abrasive wear
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in ...
, and to
galling. It can be
heat-treated for increased strength, durability, and
electrical conductivity
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity in ...
.
Beryllium copper attains the greatest strength (up to ) of any copper-based alloy. It has
thermal conductivity
The thermal conductivity of a material is a measure of its ability to heat conduction, conduct heat. It is commonly denoted by k, \lambda, or \kappa and is measured in W·m−1·K−1.
Heat transfer occurs at a lower rate in materials of low ...
of 62 Btu/h-ft-°F (107 W/m-K), which is 3–5 times higher than
tool steel
Tool steel is any of various carbon steels and alloy steels that are particularly well-suited to be made into tools and tooling, including cutting tools, dies, hand tools, knives, and others. Their suitability comes from their distinctive ...
. It has a solid melting point of 1590 °
F (866 °
C) and a liquid melting point of 1800 °F (982 °C). It has a high capacity for being hot-formed. C17200 beryllium copper alloy has strength and hardness similar to that of steel;
Rockwell hardness properties in its peaked age condition are in the range of 200 ksi and RC45.
C17200 has effective corrosion-resistant properties when exposed to harsh conditions such as seawater, and
down-hole environments. It will withstand sulphide or chloride
stress corrosion cracking and will resist the effects of carbon dioxide and hydrogen
embrittlement.
Copper alloys in general have always been considered non-sparking. C17200 has the strength to withstand use in hand and mechanical tools. These non-sparking features are best applied in explosive environments such as in the oil & gas and gunpowder industries.
Toxicity
Inhalation of dust, mist, or fumes containing beryllium can cause
chronic beryllium disease, which restricts the exchange of oxygen between the lungs and the bloodstream. The
International Agency for Research on Cancer
The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations.
Its role is to conduct and coordinate research into the causes of cancer. It also cance ...
(IARC) lists beryllium as a Group 1 human carcinogen. The
National Toxicology Program (NTP) also lists beryllium as a carcinogen. Copper beryllium alloy containing less than 2.5% beryllium (in copper) is not designated as a carcinogen.
Uses
Beryllium copper is a
non-ferrous alloy used in
springs, spring wire,
load cell
A load cell converts a force such as tension, compression, pressure, or torque into a signal (electrical, pneumatic or hydraulic pressure, or mechanical displacement indicator) that can be measured and standardized. It is a force transducer. As t ...
s, and other parts that must retain their shape under repeated stress and strain. It has high electrical conductivity and is used in low-current contacts for batteries and electrical connectors.
Beryllium copper is non-
sparking yet physically tough and
nonmagnetic, fulfilling the requirements of
ATEX directive for Zones 0, 1, and 2. Beryllium copper screwdrivers, pliers, wrenches,
cold chisels, knives, and hammers are available for environments with
explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ex ...
hazards, such as
oil rigs, coal mines, and grain elevators. An alternative metal sometimes used for non-sparking tools is
aluminium bronze. Compared to steel tools, beryllium copper tools are more expensive and not as strong, but the properties of beryllium copper in hazardous environments may outweigh the disadvantages. Some of BeCu's varied uses include:
*Certain percussion instruments, especially
tambourines and
triangles, because of beryllium copper's consistent tone and resonance.
*Ultra-low temperature
cryogenic
In physics, cryogenics is the production and behaviour of materials at very low temperatures.
The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington, DC in 1971) endorsed a univers ...
equipment, such as
dilution refrigerators, because of its mechanical strength and relatively high thermal conductivity in this temperature range.
*Molds for manufacturing plastic containers (including most plastic milk jugs), with the
blow molding process.
*
Armour piercing bullet
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constru ...
s,
though such an application is unusual, as bullets made from steel alloys are much less expensive and have similar properties.
*
Measurement-while-drilling (MWD) tools in the
directional drilling industry. A non-magnetic alloy is required, as
magnetometers are used for field-strength data received from the tool.
*Servicing
magnetic resonance imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...
(MRI) machines, where high-strength magnetic fields make the use of ferrous tools dangerous, and where magnetic materials in the field can disturb the image.
*Gaskets used to create an RF-tight (resistant to radio frequency leakage) seal, the electronic seal on doors used with
EMC testing, and
anechoic chamber
An anechoic chamber (''an-echoic'' meaning "non-reflective" or "without echoes") is a room designed to stop reflection (physics), reflections or Echo (phenomenon), echoes of either sound or electromagnetic waves. They are also often isolate ...
s.
*In the 1980s, beryllium copper was used in the manufacture of
golf clubs, particularly
wedges and
putters. Though some golfers prefer the feel of beryllium copper club heads, regulatory concerns and high costs have made beryllium copper clubs difficult to find in current production.
*Kiefer Plating (defunct) of
Elkhart, Indiana
Elkhart ( ) is a city in Elkhart County, Indiana, United States. The population was 53,923 at the 2020 census. The city is located east of South Bend, Indiana. It is the most populous city in the Elkhart–Goshen metropolitan area, which in tu ...
built beryllium-copper
trumpet bells for the Schilke Music Co. of Chicago. These lightweight bells produce a sound preferred by some musicians.
*Beryllium copper wire is produced in many forms: round, square, flat, and shaped, in coils, on spools, and in straight lengths.
*Beryllium copper valve seats and guides are used in high-performance four-stroke engines with coated titanium valves. BeCu dissipates heat from the valve as much as seven times faster than powdered steel or iron seats and guides. The softer BeCu reduces valve wear and increases valve life.
Age-hardened alloy
Beryllium copper (C17200 & C17300) is an
age-hardening alloy that attains the highest strength of any copper base alloy. It may be age hardened after forming into springs, intricate forms, or complex shapes. It is valued for its
elasticity, corrosion resistance, stability, conductivity, and low creep.
Tempered beryllium copper is C17200 and C17300, which have been age-hardened and cold-drawn. No further heat treatment is necessary beyond possible light stress relief. It is sufficiently ductile to wind on its diameter and can be formed into springs and most shapes. The tempered wire is most useful where the properties of beryllium copper are desired, but the age-hardening of finished parts is not practical.
C17510 and C17500 beryllium copper alloys are age-hardenable and provide good electrical conductivity, physical properties, and wear-resistance. They are used in springs and wire where electrical conduction or retention of properties at elevated temperatures is important.
Specialized variants
''High-strength beryllium copper'' alloys contain as much as 2.7% beryllium (cast), or 1.6-2% beryllium with about 0.3%
cobalt
Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. ...
(wrought). The strength is achieved by age hardening. The thermal conductivity of these alloys lies between that of steel and aluminum. The cast alloys are frequently formed with injection molds. The wrought alloys are designated by
UNS 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, producing a precipitation of metastable
beryllide crystals in the copper matrix. Over-aging beyond the equilibrium phase depletes the beryllide crystals and reduces their strength. The beryllides in cast alloys are similar to those in wrought alloys.
''High conductivity beryllium copper'' alloys contain as much as 0.7% beryllium with some nickel and cobalt. The thermal conductivity of these alloys is greater than that of aluminum and slightly less than that of pure copper; they are often used as electrical contacts.
References
External links
Standards and properties - Copper and copper alloy microstructures - Copper Beryllium*
ttps://web.archive.org/web/20080302034606/http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory - Copper and compounds fact sheetbr>
Copper beryllium and nickel beryllium datasheets
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{{DEFAULTSORT:Beryllium Copper
Copper alloys
Beryllium alloys
pl:Brązy#Brąz berylowy