Page 87 of 561

SOLUTIONS: Cast Iron

Groove preparation by electrode gouging The most efficient method of removing unwanted metal and preparing surfaces for welding is to use gouging and chamfering electrode Unitor CH-2 382.

2.07

This method of groove preparation requires no other equipment than that used for ordinary arc welding and gives a very attractive U-shaped groove that is clean, bright and makes an ideal base for welding. In addition it gives the advantage that if the

part to be welded is oil-impregnated

(as a number of cast iron parts are bound to be), the heat generated by the process will cause the oil to evaporate from the graphite flakes in the welding zone.

Another advantage is using CH-2 382 to prepare the metal for welding is the small amount of heat imparted to the casting prior to welding. By removing the chill from the metal welding will be easier. The filler metal will have better flow characteristics and improved welds will be evident.

A crack in cast iron. The carbon flakes in the metal are saturated with oil.

After gouging with Unitor CH-2 382. The oily deposits in the welding area have evaporated.

For correct application of gouging electrode CH-2 382, see the data sheet under “Technical Data for Consumables”.

Repairs of areas requiring drilling and tapping Before welding areas which will subsequently require drilling and tapping, it is essential that the following procedure be followed: Always remove enough metal initially so that, after filling, the final drilling and tapping can be performed entirely in the deposited weld metal without penetrating the base metal. The variance in density in the weld

86

deposit and the base metal makes this necessary. Drill and tap breakage will result if this procedure is not adhered to. This method, of necessity, requires more preparation and welding, but increase in time and labor will be compensated for in tool savings.