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HOW
TO WELD ESCO 12 SERIES ALLOYS
Certain
of these 12 Series alloys are not meant to be welded. See chart above. Welding
can destroy the heat treatment given these parts, and cause inferior performance
or failure. As
a rule, ESCO points should never be welded, repaired, or hardfaced. They are manufactured
as hard as possible. ESCO
alloys 12E, 12C, 12M and 12T have excellent weldability. They are used for weld-on
adapters, as well as structural parts such as dragline bucket lips, cheeks and
arches; shovel dipper beams, lips and fronts; and dredge cutter arms, rings and
hubs. Structural
parts in these alloys can be hardfaced, but this is generally unnecessary because
of wear shrouds that ESCO provides to protect high wear areas. The
alloy type is prominently marked on all ESCO cast parts: 12S, 12K, etc. In cases
where extreme wear has obliterated the markings, 12 Series alloys can be identified
by their magnetism; 14 Series manganese alloys are nonmagnetic. RECOMMENDED
WELDING PROCEDURES FOR 12 SERIES ALLOYS
Follow these procedures for best
results when welding the weldable 12 Series alloys together or to other low alloy
castings, carbon steel castings, forgings, or plate. Use
filler material as specified in the table here.
• | Control
the moisture in low hydrogen electrodes by purchasing electrodes in 4.5 kg/10
lb sealed packages. Larger packages invite moisture contamination which can result
in inferior welds. | | | | • | Remove
only one hour's supply at a time. Keep the remainder in a ventilated holding oven
at 65° C/150° F. | | | | • | Bake
previously opened packages of electrodes in a ventilated oven at 260° C/500°
F for two hours before using. | | | | • | Electrodes
taken from cardboard boxes or non-airtight containers should also be heated to
260° C/500° F for two hours in a ventilated oven. Then they should be
placed in a ventilated holding oven set at 65° C/150° F while still warm.
Remove one hour's supply at a time. | | | | • | Any
electrode exposed to the air for more than one hour should be rebaked per the
instructions above. | | | | • | Preheat
and interpass temperatures are in the table here. | | | | • | When
welding, use short stringer beads and remove slag after each pass. | | | | • | Bevel
joints to get 100% weld penetration, when possible. | | | | • | All
welding should be done in the flat or horizontal position, if possible. | | | | • | Peen
each bead to reduce stress concentrations. |
DOT
HARDFACING ESCO 12 SERIES ALLOYS
• | If
hardfacing is performed, dot hardfacing is recommended over other methods. It
consists of spots or dots about 10-12 mm/ 3/8 -1/2" in diameter welded in
rows about 25-37 mm/1-1 1/2" apart. | | | | • | Dot
welding is faster, uses less material, and costs less than continuous beads or
solid overlays. It also reduces the cracking and weld failure that is common with
other methods. | | | | • | Dots
serve as good wear indicators. Reweld them before they are completely worn off. | | | | • | Use
Stoody 31 or equivalent electrodes for hardfacing. | | | | • | Always
rebuild worn areas to the original contour with an appropriate base filler material
before hardfacing. If wear is very deep or excessive, buildup with low alloy steel
plate to original contour, then use the dot hardfacing method described above. | | | |
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