I've plug welded A36 (type) plates (with counter sunk holes) onto a flat, machined part made from 1018- steel with ER70S-6 solid mig wire without any problems. Now, the customer wants to case harden this part instead. The machined material will be 8620 and A36 plates will remain the same. Question: ...

I've been welding for 27 years and I know better than to say, "I can weld anything/everything". There is a lot to experience and absorb when it comes to welding and my belief is to let my welding results do the talking for me. My approach to welding is to complete it in my mind or on paper...