WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 1
(8) Spot Weld (figure 10 on the previous page). This is a weld
made by either arc spot welding where a weld is made in one spot
by drawing the arc between the electrode and the workpiece, or
resistance spot welding where the size and shape of the
individually formed welds are limited by the size and contour of
the electrodes.
(9) Upset Weld (figure 10). This is a weld made simultaneously
over the entire area of abutting surfaces or progressively along
a joint while pressure is applied before heating is started and
is maintained throughout the heating period.
d. Welding Positions (figure 11 on the following page).
All
welding can be classified according to the position of the
workpiece or the position of the joint on the plates or sections
being welded.
There are four general positions in which welds
are required to be made. These positions are designated as flat,
horizontal, vertical, and overhead.
5.
Welding Techniques
a. General.
In metal-arc welding a number of separate factors
are responsible for the transfer of molten filler metal and
molten slag to the base metal.
Among these are the techniques
employed in the actual process of welding.
The following
subparagraphs serve to describe these techniques.
b.
Welding Current, Voltage, and Adjustments.
(1) The selections of the proper welding currents and voltages
depend on the size of the electrode, the thickness of the plate
being welded, the welding position, and the welder's skill.
Electrodes of the same size can withstand higher current and
voltage values when welding in the flat welding position than in
vertical or the overhead welding position.
In general, the
proper current and voltage settings are obtained from experience
and should fill the requirements of the particular welding
operation.
Since several factors affect current and voltage
requirements, data provided by welding apparatus and electrode
manufacturers should be used. For initial
27
Previous Page
