Английский для сварщиков. Гричин С.В. - 53 стр.

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53
finished готовый; обработанный
integrated circuitry интегральная схемотехника
fuse плавить, расплавлять
pneumatic tooling пневматический инструмент
punch presses пресс-штамп
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Text 4. Alternative Types of Welding
Cold welding
Cold welding, the joining of materials without the use of heat, can be
accomplished simply by pressing them together. Surfaces have to be well
prepared, and pressure sufficient to produce 35 to 90 percent deformation at
the joint is necessary, depending on the material. Lapped joints in sheets and
cold-butt welding of wires constitute the major applications of this
technique. Pressure can be applied by punch presses, rolling stands, or
pneumatic tooling. Pressures of 1,400,000 to 2,800,000 kilopascals (200,000
to 400,000 pounds per square inch) are needed to produce a joint in
aluminum; almost all other metals need higher pressures.
Friction welding
In friction welding two work pieces are brought together under load
with one part rapidly revolving. Frictional heat is developed at the interface
until the material becomes plastic, at which time the rotation is stopped and
the load is increased to consolidate the joint. A strong joint results with the
plastic deformation, and in this sense the process may be considered a
variation of pressure welding. The process is self-regulating, for, as the
temperature at the joint rises, the friction coefficient is reduced and
overheating cannot occur. The machines are almost like lathes in appearance.
Speed, force, and time are the main variables. The process has been
automated for the production of axle casings in the automotive industry.
Laser welding
Laser welding is accomplished when the light energy emitted from a
laser source focused upon a workpiece to fuse materials together. The limited
availability of lasers of sufficient power for most welding purposes has so far
restricted its use in this area. Another difficulty is that the speed and the
thickness that can be welded are controlled not so much by power but by the
thermal conductivity of the metals and by the avoidance of metal
vaporization at the surface. Particular applications of the process with very

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