[Farmall] Welding cast iron

Chris Klossner Klossner at worldnet.att.net
Thu Dec 28 11:35:14 PST 2006


   The problem I have found with mig welding cast iron most of the time
they use an iron based wire. Cast iron contains large amounts of carbon
in the form of graphite.  When melted by the welding process this mixes
with the weld pool. With iron filler you end up with high carbon steel
which is very hard and brittle.  This is why most cast iron rods are
nickel or stainless steel which will not absorb the carbon. Nickel makes
for a more forgiving weld when it comes to pre and post heating.
Stainless generally makes for a stronger weld but heating is more
critical.  I  recently ran across this with a cast iron clutch pilot off
of a large stationary engine.  They had built up the wear surface with a
mig welder and then tried to turn it down and had no luck. Actually
damaged their lathe trying to force it. They thought my 30" lathe would
have better luck but all that did was eat carbide. I ended up turning it
down on the crankshaft grinder.  It  was a slow process I doubt it will
ever wear out.

   The plus side of mig welding is generally less heat is generated than
with stick welding.  This helps with the preheat and post heat  problem.
I think this is how most are able to get away with it in non structural
applications.

   I do not know what the crank bracket looks like on an O-12 but on
10-20's and 15-30's they are not too bad to fix.  I turn off the part
where the mounting  bolts go till it is round. Then cut out a steel
plate to match the old mounting bracket  drill to match the turned crank
bearing and weld it together.  For that I usually use a bronze stick
electrode it seems to work well for joining cast to steel.

  Chris Klossner
 http://home.att.net/~klossner/




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