Steel Valve Body Advice Please

[madman]

I have been repairing some Cast Steel Valve bodies. I grind out the Crack ,, degrease and preheat a Little bit with a torch them hit it with a Mig Gun. Afterwards the weld looks good but when cooled down it has again a crack in it where the crack in the cast steel housing was. Any Hints tips Much appreciated Thanx guys Mike

[Chester]

Are you sure they are steel??

[shawnspeed]

Are these Tranny valve bodies??? Like powerglide??? They are cast iron if they are....better off silver solder/brazing them....Shawn

[madman]

Steel Valve Castings some weigh quite a bit. Used in Plants foor air and steam.

[Rustybolt]

Did you try and drill a hole at each end of the crack?
What about a blanket or something to keep the welded area from cooling down too fast?
Post weld heat?