Hard Facing Worn Cutting Edges - Craftsman 113.201392 Owner's Manual

of the fractured surface to llne up the two pieces. Tack-weld
or clamp parts in position. !f the crack has not separated
the casting, a vee-g_oove can be chipped out with a dla-
mond-point chisel. Chlp an inch or so beyond the visible
ends of the crack as it may extend under the surface. On
cracked water jackets, where only a seal is required, the
depth of the groove need on!y be one-half the thickness
of the casting.
Keep the casting as cool as possible and do not expect to
complete a weld in cast iron as rapidly as in the same length
in mild steel. Use a smaller rod and a slightly higher current
than for the same thickness of steel. Lay a short bead, about
an inch long, at one end of the crack and peen it immediately
with a cross-peen hammer or blunt chisel to spread the
weld metal and relieve locked-up stresses. Do not strike the
edges of the casting. Place the second bead at the opposite
end of the crack and the next in the center, etc (fig. 1_.
Allow enough time between welding to permit your bare
hand to be held on it. Never use water or a blast of air
to cool the casting. Although cracks may not show up
immediately, the locked-up stresses due to uneven cooling
will cause the casting to fail after it is back in service. Wire
brush each bead before depositing the next. Then continue
to fill the groove with short weld beads as before, worklng
rapidly when depositing and peening the bead. Allow plenty
of time for cooling. Examine the casting for cracks that may
develop during cooling periods. If any of the beads crack,
chip them out and re-weld. If cracking persists, preheat
the entire casting slowly to a dull red heat with an oxyacety-
lene torch or blow-torch. When the preheated method is
used, the welding can be continuous. After completing the
weld, cover the casting with warm dry sand or slaked llme
so it will cool slowly.
Malleable iron is ordinary gray cast iron that has been heat
treated to give it a tough ductile outer skin. The method of
welding is the same as for cast iron.
FIRST BEAD THIRD HEAD SECOND H£AD
i_ '_.4
HARD FACmNG WORN CUTTING EDGES
SPIKE
HARROW
TOOTH
Figure
INOICATES
HARO FACING
HARD FACE ON UNOERSID[
Ig SIDES
_PS
SWREP
Excavating equipment, earth-cuffing farm machinery or
others such as plow shares, lister shares, cultivator shovels,
sweeps, subsoilers, spike harrow teeth, tractor treads, ex-
cavating buckets, or any surface subject to abrasive action
will last much longer and require less sharpening when
their cutting edges are hard faced with hard surfacing
electrodes. The arc welding process consists of depositing
a layer of abrasion resisting weld metal on the worn cutting
edges as indicated in red on the parts shown in figure 1.
Prepare the part for welding by cleaning the surface to be
welded by grinding it approximately 1-1/2 inches back
from the edge (fig. 2). Position the part so weld metal can
be deposited in the flat position. If the material is 1/4-inch
thick or Jess, use a 1/8-1nch rod and as low a current as
possible that will still permit the metal to flow out smooth
and falrly thin (1/16 to 1/8-inch thick). Weave the rod
from slde-to-side in a crescent-shaped movement and de-
posit a bead about 3/4 to 1-1nch wide. Several passes
(laid slde-by-side) may be necessary where the worn sur-
faces are quite wide. In some cases a small straight bead
GR_D OFF WEJ_VEBEAHS
Figure 2 F;gure 3
HARD FACIfH HARD FACING
SOFT BASE METAL MILO-STE£L PA_/CH
W_ARSAWAY EASTEr WELDS
THAN HARD HAS]fiG Figure 5
must be deposited along the edge to build it up (fig. 3).
Make beads heaviest where the wear will be greatest, but
avoid excessive build-up as the metal cannot be filed or
machined. If shaping is required, heat the weld metal and
forge it. Smoothing and sharpening can be accomplished
by grinding.
For plow and lister shares, cuffivator shovels and similar
cutting points, deposit the weld metal on one side only
which will result in a self-sharpening edge (fig. 4). The
softer base metal on the other side will wear away first and
leave a knifedike edge of hard facing material. Parts that
must wear uniformly on both sides should be hard faced
on both sides. The condition of the worn part must also be
taken into consideration. ]f the part requires a number of
passes to bring it up to the desired thickness, use mild-stee_
welding rods first; then cover with deposited metal from
hard surfacing rods. If the edge is entirely worn away, a
steel patch (cut to fit) may be welded in place with mild-steel
electrodes, then hard faced (fig. 5). To prevent distortion
when hard facing small parts, peen the deposited weid
metal before it cools.