How can one weld austenitic stainless steel to gray cast iron?
Much depends on the configuration of the intended joint, on the thickness andconstraints and on the process being used. Assuming that the SMAW (ShieldedMetal Arc Welding) process is used, one should first clean and preheat the castiron. Then one should deposit on it a buffer layer either of stainless steel (type 309 or 312) orof nickel base alloy (ENi-CI). This procedure is called buttering. The main concern is avoiding cracks. The technique should concentrate in melting the minimum of base metal, byintroducing the least amount of heat, with the smallest electrode and the leastcurrent, with thin weld beads. The weld is built up with additional beads (afterslag removal) until finished, without cooling down. Finally the austenitic stainless steel is welded to the buffer layer. Slowcooling down to room temperature is obtained by providing insulation to the castiron or by cooling in a furnace. An interesting supplement to the above presentation was published in a note by Damian J. Kotecki,
