International Annealed Copper Standard

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The International Annealed Copper Standard (IACS) is a standard established in 1914 by the United States Department of Commerce. [1] It is an empirically derived standard value for the electrical conductivity of commercially available copper.

Standard (metrology) embodiment of a unit of measurement

In metrology, a standard is an object, system, or experiment that bears a defined relationship to a unit of measurement of a physical quantity. Standards are the fundamental reference for a system of weights and measures, against which all other measuring devices are compared. Historical standards for length, volume, and mass were defined by many different authorities, which resulted in confusion and inaccuracy of measurements. Modern measurements are defined in relationship to internationally standardized reference objects, which are used under carefully controlled laboratory conditions to define the units of length, mass, electrical potential, and other physical quantities.

Copper Chemical element with atomic number 29

Copper is a chemical element with symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Sometime around 1913 several copper samples from 14 important refiners and wire manufacturers were analyzed by the U.S. Bureau of Standards. The average resistance of the samples was determined to be 0.15292 Ω for copper wires with a mass of 1 gram of uniform cross section and 1 meter in length at 20 °C. In the United States this is usually written as "0.15292 ohm (meter, gram) at 20 °C".

Ohm SI derived unit of electrical resistance

The ohm is the SI derived unit of electrical resistance, named after German physicist Georg Simon Ohm. Although several empirically derived standard units for expressing electrical resistance were developed in connection with early telegraphy practice, the British Association for the Advancement of Science proposed a unit derived from existing units of mass, length and time and of a convenient size for practical work as early as 1861. The definition of the ohm was revised several times. Today, the definition of the ohm is expressed from the quantum Hall effect.

Gram Unit of mass 1/1000th of a kilogram

The gram is a metric system unit of mass.

Cross section (geometry) the intersection of a body in 3D space with a plane, or the analog in higher-dimensional space. Cutting an object into slices creates many parallel cross sections. A cross section of 3D space that is parallel to two of the axes is a contour line

In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross sections. The boundary of a cross section in three-dimensional space that is parallel to two of the axes, that is, parallel to the plane determined by these axes, is sometimes referred to as a contour line; for example, if a plane cuts through mountains of a raised-relief map parallel to the ground, the result is a contour line in two-dimensional space showing points on the surface of the mountains of equal elevation.

Germany proposed a slight modification of this value to "0.15328 ohm (meter, gram) at 20 °C", this being equivalent to a conductivity of exactly 58×106  S/m at 20 °C. The German modification was adopted by the International Electrotechnical Commission in 1913 and subsequently published by the United States Department of Commerce on October 1, 1914 as the International Annealed Copper Standard (IACS).

The siemens is the derived unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI). Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is redundantly equal to the reciprocal of one ohm, and is also referred to as the mho. The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971.

International Electrotechnical Commission organization

The International Electrotechnical Commission is an international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology". IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology and marine energy as well as many others. The IEC also manages three global conformity assessment systems that certify whether equipment, system or components conform to its International Standards.

United States Department of Commerce government agency

The United States Department of Commerce is the Cabinet department of the United States government concerned with promoting economic growth. Among its tasks are gathering economic and demographic data for business and government decision-making, and helping to set industrial standards. This organization's main purpose is to create jobs, promote economic growth, encourage sustainable development and improve standards of living for all Americans. The Department of Commerce headquarters is the Herbert C. Hoover Building in Washington, D.C.

The standard is most often used as a comparative property in the specification of the conductivity of other metals. For example, the conductivity of a particular grade of titanium may be specified as 1.2 % IACS, meaning that its electrical conductivity is 1.2 % of the copper specified as the IACS standard. [2]

Titanium Chemical element with atomic number 22

Titanium is a chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine.

The standard can be found at https://archive.org/stream/copperwiretables31unituoft#page/n0/mode/1up.

Quality of aluminum alloys

Heat treatment will alter several properties of an alloy, many of which are important to a design engineer. A measurement of the electric conductivity of aluminum alloys can be used to verify that a heat treatment process has been done correctly. For example a component made of "7075" alloy which was correctly treated with the process "T73" to gain resistance to stress corrosion cracking will fall in the range of 38.0 to 43.0 % IACS. [3]

Stress corrosion cracking

Stress corrosion cracking (SCC) is the growth of crack formation in a corrosive environment. It can lead to unexpected sudden failure of normally ductile metals subjected to a tensile stress, especially at elevated temperature. SCC is highly chemically specific in that certain alloys are likely to undergo SCC only when exposed to a small number of chemical environments. The chemical environment that causes SCC for a given alloy is often one which is only mildly corrosive to the metal. Hence, metal parts with severe SCC can appear bright and shiny, while being filled with microscopic cracks. This factor makes it common for SCC to go undetected prior to failure. SCC often progresses rapidly, and is more common among alloys than pure metals. The specific environment is of crucial importance, and only very small concentrations of certain highly active chemicals are needed to produce catastrophic cracking, often leading to devastating and unexpected failure.

The acceptance criteria for electrical conductivity of finished or semi-finished parts of wrought aluminum alloys are contained in SAE International specification AMS2658 Hardness and Conductivity Inspection of Wrought Aluminum Alloy Parts. Here the values are given in reference to the IACS.

A method for measuring electrical conductivity is described in ASTM International specification ASTM E 1004 Electromagnetic (Eddy-Current) Measurements of Electrical Conductivity.

Related Research Articles

Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze and spring copper, is a copper alloy with 0.5—3% beryllium and sometimes other elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has excellent metalworking, forming and machining properties. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and aerospace. Beryllium alloys present a toxic inhalation hazard during manufacture.

Electrical conductor object or material which permits the flow of electricity

In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge in one or more directions. Materials made of metal are common electrical conductors. Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases.

Oxygen-free copper

Oxygen-free copper (OFC) or oxygen-free high thermal conductivity (OFHC) copper is a group of wrought high conductivity copper alloys that have been electrolytically refined to reduce the level of oxygen to .001% or below.

Aluminium alloy alloy in which aluminium is the predominant metal

Aluminium alloys are alloys in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4.0–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.

6061 is a precipitation-hardened aluminum alloy, containing magnesium and silicon as its major alloying elements. Originally called "Alloy 61S", it was developed in 1935. It has good mechanical properties, exhibits good weldability, and is very commonly extruded. It is one of the most common alloys of aluminum for general-purpose use.

Copper conductor

Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor.

2014 aluminium alloy (aluminum) is an aluminium-based alloy often used in the aerospace industry.

1050 aluminium alloy is an aluminium-based alloy in the "commercially pure" wrought family. As a wrought alloy, it is not used in castings. Instead, it is usually formed by extrusion or rolling. It is commonly used in the electrical and chemical industries, on account of having high electrical conductivity, corrosion resistance, and workability. 1050 alloy is also sometimes used for the manufacture of heat sinks, since it has a higher thermal conductivity than other alloys. It has low mechanical strength compared to more significantly alloyed metals. It can be strengthened by cold working, but not by heat treatment.

1060 aluminium alloy is an aluminium-based alloy in the "commercially pure" wrought family. It is fundamentally very similar to 1050 aluminium alloy, with the difference coming down to 0.1% aluminium by weight. However, while both 1050 and 1060 are covered by the same ISO standard, they are covered by different ASTM standards.

1100 aluminium alloy is an aluminium-based alloy in the "commercially pure" wrought family. With a minimum of 99.0% aluminum, it is the most heavily alloyed of the 1000 series. It is also the mechanically strongest alloy in the series, and is the only 1000-series alloy commonly used in rivets. At the same time, it keeps the benefits of being relatively lightly alloyed, such as high electrical conductivity, thermal conductivity, corrosion resistance, and workability. It can be strengthened by cold working, but not by heat treatment.

2219 aluminium alloy is an alloy in the wrought aluminium-copper family. It can be heat-treated to produce tempers with higher strength but lower ductility. The aluminium-copper alloys have high strength, but are generally less corrosion resistant and harder to weld than other types of aluminium alloys. To compensate for the lower corrosion resistance, 2219 aluminium can be clad in a commercially pure alloy such as 1050 or painted. This alloy is commonly formed by both extrusion and forging, but is not used in casting.

3004 aluminium alloy is an alloy in the wrought aluminium-manganese family. It is similar to the 3003 alloy, except for the addition of approximately 1% magnesium. It can be cold worked to produce tempers with a higher strength but a lower ductility. Like most other aluminium-manganese alloys, 3003 is a general-purpose alloy with moderate strength, good workability, and good corrosion resistance. It is commonly rolled and extruded, but typically not forged. As a wrought alloy, it is not used in casting.

3102 aluminium alloy is an alloy in the wrought aluminium-manganese family. It is one of the most lightly alloyed grades in the 3000 series, with at least 97.85% aluminium by weight. Like most other aluminium-manganese alloys, 3102 is a general-purpose alloy with moderate strength, good workability, and good corrosion resistance. Being lightly alloyed, it tends on the lower strength and higher corrosion resistance side. It can be cold worked to produce tempers with a higher strength but a lower ductility. It can be formed by rolling, extrusion, and forging. As a wrought alloy, it is not used in casting.

5154 aluminium alloy is an alloy in the wrought aluminium-magnesium family. As an aluminium-magnesium alloy, it combines moderate-to-high strength with excellent weldability. 5154 aluminium is commonly used in welded structures such as pressure vessels and ships. As a wrought alloy, it can be formed by rolling, extrusion, and forging, but not casting. It can be cold worked to produce tempers with a higher strength but a lower ductility. It is generally not clad.

5454 aluminium alloy is an alloy in the wrought aluminium-magnesium family. It is closely related to 5154 aluminium alloy. As an aluminium-magnesium alloy, it combines moderate-to-high strength with excellent weldability. Like 5154, 5454 aluminium is commonly used in welded structures such as pressure vessels and ships. As a wrought alloy, it can be formed by rolling, extrusion, and forging, but not casting. It can be cold worked to produce tempers with a higher strength but a lower ductility. It is generally not clad.

5456 aluminium alloy is an alloy in the wrought aluminium-magnesium family. While it is closely related to 5356 aluminium alloy, it is used in structural applications, like most other aluminium-magnesium alloys, and not as filler for welding. As a wrought alloy, it can be formed by rolling, extrusion, and forging, but not casting. It can be cold worked to produce tempers with a higher strength but a lower ductility. It is susceptible to exfoliation corrosion when held at temperatures above 65 °C (150 °F) for extended periods of time.

5754 aluminium alloy is an alloy in the wrought aluminium -magnesium family. It is closely related to the alloys 5154 and 5454. Of the three 5x54 alloys, 5754 is the least alloyed, but only by a small amount. It is used in similar applications. As a wrought alloy, it can be formed by rolling, extrusion, and forging, but not casting. It can be cold worked to produce tempers with a higher strength but a lower ductility.

6005A aluminium alloy is an alloy in the wrought aluminium-magnesium-silicon family. It is closely related, but not identical, to 6005 aluminium alloy. Between those two alloys, 6005A is more heavily alloyed, but the difference does not make a marked impact on material properties. It can be formed by extrusion, forging or rolling, but as a wrought alloy it is not used in casting. It cannot be work hardened, but is commonly heat treated to produce tempers with a higher strength at the expense of ductility.

6262 aluminium alloy is an alloy in the wrought aluminium-magnesium-silicon family. It is related to 6162 aluminium alloy, but sees much more widespread use. It is notably distinct from 6162, and most other aluminium alloys, in that it contains lead in its alloy composition. It is typically formed by extrusion, forging, or rolling, but as a wrought alloy it is not used in casting. It can also be clad, but that is not common practice with this alloy. It cannot be work hardened, but is commonly heat treated to produce tempers with a higher strength but lower ductility.

References

  1. Copper Wire Tables, (Technical report). Circular of the Bureau of Standards No.31 (3d ed.). United States Department of Commerce. October 1, 1914.
  2. "Resistivity and Conductivity Units Converter".
  3. "Stress Corrosion Cracking of Aluminum Alloys". Total Materia. June 2001. Retrieved 14 April 2016.