Английский для сварщиков. Гричин С.В. - 64 стр.

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Below find information about some less frequently used arc welding
processes. After reading the text, think and say why these processes are less
common in industry. Consider their advantages and disadvantages.
Atomic Hydrogen Welding (AHW) is an arc welding process that uses an
arc between two metal tungsten electrodes in a shielding atmosphere of
hydrogen and without the application of pressure. Shielding is obtained from
the hydrogen. Filler metal may or may not be used. In this process, the arc is
maintained entirely independent of the work or parts being welded. The
work is a part of the electrical circuit only to the extent that a portion of the
arc comes in contact with the work, at which time a voltage exists between
the work and each electrode.
Carbon Arc Welding (CAW) is a process which produces coalescence of
metals by heating them with an arc between a nonconsumable carbon
(graphite) electrode and the work-piece. It was the first arc-welding process
ever developed but is not used for many applications today, having been
replaced by twin carbon arc welding and other variations.
Twin carbon arc welding (TCAW) in which the arc is established between
two carbon electrodes
Gas carbon arc welding (CAW-G) no longer has commercial significance
Electroslag welding is a highly productive welding process developed in the
United States during the 1930s. It involves the melting of the surfaces of the
metal workpieces and the filler metal with a molten slag to cause
coalescence. An electric arc is passed through the slag to heat it, but the arc
itself is extinguished by the slag. Electroslag welding is commonly used to
weld in a vertical orientation, and is particularly popular with steels. In the
1970s, it was used extensively in bridges, ships, and other large metal
structures. However, in 1977 the Federal Highway Administration banned its
use in welds for some structural members of bridges, due to concerns of weld
imperfections and poor properties. Benefits of the process include its high
metal deposition rates. Many welding processes require more than one pass
for welding thick workpieces, but often a single pass is sufficient for
electroslag welding. The process is also very efficient, since joint preparation
and materials handling are minimized while filler metal utilization is high.
The process is also safe and clean, with no arc flash and low weld splatter or
distortion.
Electrogas welding (EGW) is a continuous vertical position arc welding
process developed in 1961, in which an arc is struck between a consumable
electrode and the workpiece. A shielding gas is sometimes used, but pressure

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