REBUILDING AND HARD-FACING CRUSHER
ROLL SHELLS (Continued)
After the center section of this roll has been built up by
Rebuilding Shells with the Manual Process
this first layer, repeat the same procedure using
transverse beads of longer length. See steps numbers 4
Always rebuild badly worn, dished rolls before
through 6 in Figure 2-66. Generally two layers are
hard-facing. On manganese castings, use electrodes on
pages 1-22 or 1-20 with the manual process. (NOTE:
sufficient to restore roll size. If the shell is badly worn,
apply additional layers. The rolls must be brought to
NEVER USE MILD STEEL FOR REBUILDING
size and correct contour before hard-facing.
A crescent weave bead of 1/2 - 3/4 in. maximum width
will produce a sound deposit.
Using the skip weld process, apply transverse beads in
Hard-facing Crusher Shells with the Manual Process
the center section of the roll in the area of deepest wear.
Use electrode on page 1-25 to hard-face crusher
Deposit three or four beads about 6 in. apart and turn
the roll to a new position. Follow this pattern until
shells. If a more abrasive resistance on the shell is
weld beads are applied to the entire circumference of
desired, use electrode on page 1-26.
the roll. Continue the skip weld process until
successive spaces between the original beads are
gradually closed in and the entire center area of the roll
is overlaid. See steps number 1 through 3 in Figure