Spot welding of different metals
Though, mild steel is t he metal most commonly used, any prime metal or alloy can be successfully spot welded provided that machine with suitable capacity and control gear is employed. Following three points to be borne in mind while employing resistance spot welding.
i). The capacity of the machine will vary according to the electrical conductivity of the material.
ii). Unstable alloys should always be welded as rapidly as possible.
iii). Welds in materials whose properties are much affected by changes of temperature can frequently be improved by subsequent heat treatment.