Taylor 1200E, Руководство по эксплуатации

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V - 21A
STUDWELDING TECHNIQUES
22
5. WELDING STUDS LESS THAN 25 mm LONG USING FERRULES.
As we have seen previously, the stud is held in a recess in the chuck and must be long
enough to allow us to set the correct protrusion. A standard chuck has a recess 12 mm
deep and ferrules vary in length up to 13.5 mm high. Thus if a stud is much less than 25 mm
LAW we shall not be able to obtain the correct protrusion, i.e.. The chuck may hit the
ferrule on the return stroke and prevent the stud returning to the plate correctly.
This problem may be overcome by using "shallow recess" chucks (the recess depth is only 6
mm) or if the studs are required to be very short, by using a special type of stud known as a
"break
- off" type. These studs have an overall LAW of 30 mm and are welded using a
standard chuck and ferrule. The stud is "grooved" at the required length from the welding
end. After welding, the surplus portion of the stud is broken off with a pair of pliers. By
these means, very short studs can easily be welded.
6. USING TEMPLATES TO ENSURE POSITIONAL ACCURACY.
When welding studs around the periphery of a flange, i.e. for cover plates, inspection doors
etc., positioning of the studs in relation to each other becomes most important. A simple
template made from 2 mm sheet, shaped to suit the component and provided with clamps
is usually the answer to this problem. The position of the studs is accurately marked and
holes drilled in these positions to accept either the ferrule of the stud to be welded or, if
using short cycle, the pistol gas shroud. The size of the holes should be the outside
diameter of the ferrule / 0.4 mm. It is also advisable to provide 2 mm thick pads
underneath the template so that there is a space between the component and template,
this space will allow the gases developed during welding to vent properly from the ferrule /
shroud. For any further advice or help in the design of jigging or templates contact your
local field sales engineer.
7. MINIMUM PLATE THICKNESSES WHEN STUD WELDING.
When using standard Drawn Arc with ceramic ferrules, the minimum ratio of stud diameter
to plate thickness is 4 : 1 for plate thickness greater than 3 mm and 3 : 1 for plate thickness
between 1.5 mm and 3 mm. When using the short cycle system with or without gas purging
it is possible to weld equivalent size studs onto slightly thinner sections, due to the short
weld duration. These ratios ensure that the strength of the plate is sufficient to support a
stud of a given size when it is loaded, without there being a tendency for the plate to
distort.
Occasionally, however, it may be necessary to weld a stud outside of these ratios. This can
sometimes be accomplished without distortion by "heat sinking" the component, by using a
flat copper or water cooled backing piece behind the weld area, to support the plate and
assist in dissipating heat quickly.
8. WELDING STAINLESS STEEL.
Austenitic stainless steel studs of the 18/8 g/N : weld decay proof type can be supplied for
welding to similar parent material or mild steel. The technique does not differ from that
used for mild steel stud welding. There is a tendency with larger diameters of stainless steel
studs for metal transfer across the arc to take the form of large particles. If short circuits
occur then the arc can be heard to splutter. This may occur with any diameter of stainless
steel stud if the lift of the hand tool is not correct. Due to this tendency to transfer in large
particles increased lift may be required and time settings should be kept as low as possible.