Cast steel can be welded using the same electrodes and procedures used to weld wrought steel.
In a very complicated or thin cast steel section, the heat should be distributed as widely as possible, and in extreme cases the welding operation should be carried on intermittently to allow the heat to be distributed over the workpiece, so that a sufficient amount of heat is not concentrated at one point to cause undue or harmful expansion of the metal.
Wear-Resistant Surface- For a manganese steel casting used, for example in railway crossovers, satisfactory welding can be done using a 12% manganese steel electrode.
Wherever possible, a weld made in a steel casting should be reinforced so that the section of the weld is larger than the original adjacent section. This is needed due to the low degree of ductility compared with the ductility of the original casting.
Fatigue Failures- Cast steel is generally presumed to have less resistance to fatigue than rolled steel. Castings subjected to alternating stresses of tension and compression will provide service for a given length of time but may eventually fail. The initial failure due to breakage may be repaired by welding, but in a comparatively short length of time, another failure may occur in some other pari of the casting. One explanation for this reaction is that at the time of initial failure, the metal of the casting had undergone its limit of fatigue. If the casting had been annealed, the later failures would probably have been eliminated. Frequently steel castings which have been repeatedly subjected to high temperatures cannot be welded. This occurs particularly in the case of annealing pots and annealing boxes. In such a case it is impossible to get a reasonable degree of fusion between the added metal and the metal of the original piece.