![]() The tough properties of manganese can be lost if the base metal is continually heated above 500☏ (260☌). In order of decreasing penetration and dilution - vertical up (highest), horizontal, up hill, flat and down hill (lowest). When using wire processes, a longer stick-out will reduce penetration.Ĩ. Regardless of stringer or wide weave beads, the travel speed should be adjusted to direct the arc on the weld puddle.ħ. Use DC straight polarity if possible (electrode negative).ĥ. If it is necessary to apply more layers than is specified for the alloy, a build-up material should be applied first.Ĥ. Unless an alloy has been specifically designed and tested for multi-layer weld overlays, the following guide lines should be useful to determine the number of hardface layers that should be applied. Furthermore, as hardface overlays increase in hardness, they tend to be more brittle. Thick hardfacing deposits may crack and break off rapidly in service. Cracks should be transverse across the weld and less than 1” apart. These cracks do not normalloy extend into the base material and do not weaken the bond to the base. A regualr check patters is desirable as it will reduce or even eliminate the tendency for distortion. They appear during cooling and are due to the different shrinkage rates between the hard surfacing material and the base material. The more wear resistant the deposit and the higher the alloy content and hardness, the greater will be the tendency to crosscheck. If a manganese part is to be repaired repeatedly, such as hammers or railroad frogs and switches, apply one or two layers of Postalloy®2865-FCO (207 electrode) the first time is very beneficial.Į. Never use a mild or low alloy steel on manganese. The part that is easiest to change out or hardface should be about 10 points softer than the part that is more complicated to work on.Ĭ. When two metal parts come in contact with each other, the following guideline is suggested. It does not have the hardness and strength for hardfacing applications.ī. The softer alloy should always be applied beneath the harder deposit. Never put a soft, ductile weld metal or a work-hardening manganese alloy on top of a harder, more brittle hardfacing alloy. ![]() A second layer, in either case will produce a chemistry suitable for wear resistance.Ī. Straight polarity, on the other hand, results in less penetration and more favorable deposit chemistry. Reverse polarity results in a first layer deposit that is up to 50% base metal and 50% weld metal. Weld Polarity Weld polarity strongly effects the amount of dilution. if a build-up is needed prior to hardfacing, select a build-up that is compatible with the base metal composition. This causes excessive mixing of the base metal and hardfacing alloy. ![]()
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