We are currently welding a .248 thick 1018 case hardened .005-.010 deep blade to a .126 1008 base. Welding consists of two fillet welds 1.8" long. Due to geometry torch angle is not optimum. We are using an ABB robot with Miller 450 Deltaweld. Wire is .045 ER70S6, Gas is 92%Ar, 8% CO2. Settings are 50ipm weld speed, 28 volts (spray weld) and 375 ipm wire feed. On most blade batches these settings are fine, however we get batches of heat treated blades where weld porosity causes us to scrap a lot of parts. Blades are still to specification but weld is adversely affected. We have experimented with the settings with little success. Does anyone have any positive experiences welding a case hardened part to a soft part. If so what were your parameters (wire, gase, weld speed, volts, wire feed)?