Jeff Hardfacing with Stellite 6 requires careful surface preparation, pre-heating considering S.S 410 material to Stellite 6 weld surfacing, buttressing and final PWHT. Please review the weld procedure and PQR to meet ASME Sec IX. Did you get multiple scc in overlay weld or it is a guess from your end? Trust this is of help to you C.V.Srinivasan may 04,2005 >I have a customer who is using one of my valves in a paper >mill. The valve has a 410 stainless steel piston with a >Stellite 6 hardfacing (overlay). The Stellite 6 overlay >failed; it came off the stainless steel 410 piston, right at >the weld interface. I'm suspecting the high chlorides in >their water attacked the weld interface. Does this seem >reasonable to you? The piston supposed to be post weld heat >treated to releive weld stresses.

Try using a Ni30Cr10Mo buffer layer between Stellite and 410SS. Crevelloy or similar. Observe highest preheat recommended for 410SS when welding. Avoid draughts and slow cool in Oven before PWHT. After PWHT apply Stellite to the Crevelloy with 300-400deg C Oven PreHeat (Minimum allowed is 250dgC)and maintained by gas burner, protect from drafts, at stop starts. With GTAW avoid crater cracks by moving the arc back over stop and then forward with slow lift off (S finishing). Avoid heavy beads and more than 2 passes. At end of welding, either keep the pre heat appplied with work piece turning on rollers gradually turning down the pre-heat and finally wrap well with insulation or place the work piece immediated in an Oven set to max pre-heat of 450 deg C and allow a furnace cool of about 60degC/ hour. Stellite gives you hard wearing corrosion resisitance and the Crevelloy superb crevice corrosion resistance in the case of the Stellite cracking. The Crevelloy has expansion coefficient similar to Stellite and has good ductility to accomodate differential between Crevelloy & 410SS.