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+ | ====== Exothermic Welding ====== | ||
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+ | 3CuO + 2Al → 3Cu + Al2O3 + Heat.[1] | ||
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+ | This chemical reaction reaches a temperature of 1,400 °C (1,670 K). The reactants are usually supplied in the form of powders, with the reaction triggered using a spark from a flint lighter. The activation energy for this reaction is very high however, and initiation requires either the use of a " | ||
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+ | The process employs a semi-permanent graphite crucible mould, in which the molten copper, produced by the reaction, flows through the mould and over and around the conductors to be welded, forming an electrically conductive weld between them.[1] When the copper cools, the mould is either broken off or left in place.[2] Alternatively, | ||
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+ | The weld formed has higher mechanical strength than other forms of weld, and excellent corrosion resistance. It is also highly stable when subject to repeated short-circuit pulses, and does not suffer from increased electrical resistance over the lifetime of the installation. However, the process is costly relative to other welding processes, requires a supply of replaceable moulds, suffers from a lack of repeatability, | ||
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+ | Exothermic welding is usually used for welding copper conductors but is suitable for welding a wide range of metals, including stainless steel, cast iron, common steel, brass, bronze, and Monel.[2] It is especially useful for joining dissimilar metals.[3] The process is marketed under a variety of names such as [[Cadweld]], | ||
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+ | The first non-ferrous application for exothermic welding was developed in 1938 by Dr. Charles Cadwell, a professor at the Case School of Applied Science (now Case Western Reserve University), | ||
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+ | ---- | ||
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+ | [1] Milenko Braunović, Valeriĭ Vasilʹevich Konchits, and Nikolaĭ Konstantinovich Myshkin (2006). Electrical Contacts: Fundamentals, | ||
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+ | [2] John Crisp (2002). Introduction to copper cabling. Newnes. pp. 88. ISBN 0750655550. | ||
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+ | [3] Jerry C. Whitaker (2005). The electronics handbook (2nd ed.). CRC Press. pp. 1199. ISBN 0849318890. | ||