REBUILDING AND HARD-FACING CRUSHER
ROLL SHELLS (Continued)
3. Weld heavy 4 in. angle iron 1 in. from, and parallel
It is often desirable to stripe only one roll when
to, each side of the crack. Use electrode on page
extremely fine aggregate is being produced. A
1-27 to join angle iron to shell.
transverse deposit of hard metal is applied to the
entire surface of the smooth roll, using welding
4. Drill or bum 1-1/8 in. holes in each angle iron on 6
procedure outlined in the section on roll rebuilding.
in. centers to accommodate 1 in. bolts, Run bolts
The hard metal overlay should not be reapplied until
through angle irons and tighten nuts progressively
most of the previous metal has worn off. Otherwise,
to bring shell together.
severe cracking or spalling may occur.
5. Use electrodes on pages 1-22 or 1-20 to weld
How to Repair Cracked Manganese Rolls
shell. Use weave or oscillating beads to work out
all gas from molten puddle.
The following procedures describe how to repair
cracked manganese rolls (Figure 2-69).
6. Scarf off angle iron and rehard-face where
Loosen all wedge bolts and wedges.
7. Secure wedge bolts and wedges.
2. Vee out the crack to provide a 600 angle for
welding. Remove all hard-facing adjacent to
and back about 6 in. from the edges of the