Dears
We have the next trouble on  tubesheet some cracks appears after welding process, the cracks appears in the new weld around tube or appears in Another old weld around tube, the welding process is  SMAW and doing preheating with torch, the tube sheet .material is SA 266 gr2 p1 we want change the  wps to use GMAW with CO2 and preheat with electrical resistance, ours doub is about sulfur elemental  can damage the steel structure during opertaions is necessary apply some heat treatment to remove any contamination by sulfur and restore the ductility to 1100F early yo weld?? Services temperature 250C