WELDING CARBON STEEL
Low-carbon mild steel is not only the
most widely used metal; it is also the easiest to weld. Although most steel
welding is done today with coated electrodes,
or by one of the consumable-wire arc welding processes, oxy-
acetylene welding of steel, especially
in thicknesses of 1/4 in. (6 mm) or less, is still widely employed. A well-
trained oxy-acetylene welder, working
on steel 1/8 in. (3 mm) thick, can usually make welds
of better quality than can
the average arc welder, and make them almost as rapidly.
Once you have mastered the art of welding
steel, you are ready to tackle some of the metals which are more
difficult to weld. Steel should always
be the starting point. In
this chapter, the specific instructions for welding will be given in the form
of captions accompanying Fig. 13-1 through
13-19. Fig. 13-1 through 13-4 deal with welding of sheet, Fig. 13-5 through 13-12
with the welding of plate, Fig.
13-13 through 13-19 with the welding of pipe. If you are teaching yourself to
weld from this book, without the aid
of a good instructor, we urge you to work your way through Fig. 13-12, in sequence,
then decide whether or not you
wish to tackle pipe. However, if you are definitely interested in learning to
weld steel pipe, and feel that you are doing
well after getting through Fig. 13-6, you may properly skip from Fig. 13-6 to
Fig. 13-13, assuming that you can
secure an adequate supply of properly-bevelled pipe, 2 to 4 in. in diameter.
*In previous editions of this Handbook,
the welding of steel sheet, steel plate, and steel pipe were covered in separate
chapters. For two reasons,
we have elected to treat the welding of steel in one continuous chapter in this
edition. The first is this: In previous editions, the technique
of flame and rod movement recommended for welding sheet was quite different from
that recommended for welding plate and pipe.
That technique is still valid, especially for the welding of the thinnest sheet
(less than 1/16 in., or 16-gauge),
and will be covered at the close
of this chapter. In most situations, however, the same technique used for welding
plate and pipe can be used for welding sheet, and it is
easier to master. The second reason concerns pipe welding: Earlier editions of
the Handbook treated pipe welding chiefly in terms of rather
large-diameter pipe, which is seldom oxy-acetylene welded today. Oxy-acetylene
welding of pipe is today largely restricted to pipe sizes
ranging from 1/2 in. to 4 in.
The technique used for welding pipe in those sizes is essentially no different
than that used for welding plate
or sheet of equivalent thickness.