The use of oxygen to gas welding are the ways in which the metal is heated high-temperature gas flame through a special welding torch. For welding of many metals is practically suitable flame at a temperature not lower than 3000 ° C. At the present time for gas-welding flame burn almost exclusively different fuels in a technically pure oxygen. Combustion of various fuels in air gives a flame with a very low temperature (not above 1800-2000 ° C), suitable for welding a very low-melting metals such as lead. Low temperature gas-flame and its suitability for small gas welding of metals is explained by a high content in the air, inert gases, mainly nitrogen, are not involved in the process of combustion, and dramatically reduce the effects and pyrometric temperature of the flame. When burning the same fuel and oxygen in the air, the overall effect of thermal or calorimetric combustion reaction in both cases is practically the same, but the flame temperature dramatically different. For ordinary cases, the welding industry, applies only flame obtained by burning fuel in a technically pure oxygen. Gas-flame can be kept in the welding technique is of limited use.
Technically, pure oxygen is the most important gas in welding technology, processes for gas welding and oxygen cutting. It is also necessary for other processes such as chemical, metallurgical and other industries, etc. For many of these productions do not require high purity of oxygen used, and sufficient supplies of cheap gas, containing oxygen in it only 50-90%. In the welding technique used high-purity oxygen, in any case not less than 98.5%
Methods of production of commercially pure oxygen may be different; industrial importance are two ways to obtain: a) from the air - a method of deep cooling and b) from the water - by means of electrolysis. In our industry is almost exclusively used method of producing oxygen from the air, as more economical, which consumes 0.5 - 1.6 kW / h of electricity per 1 m 3 of oxygen, for 1 m 3 of oxygen by electrolysis of water with simultaneous reception of 2 m three hydrogen requires 12.10 kW / h Getting oxygen means electrolysis of water can be profitable only if the simultaneous use of hydrogen produced.
See also:
Gas Welding Technology
Transportation and Storage of Oxygen
When To Use Oxgen Gas Welding
Production of Oxygen from Air
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