On Sat, 24 Sep 2016 14:07:55 -0400, wrote:

On Sat, 24 Sep 2016 09:26:44 -0400, Leon Fisk
wrote:

On Thu, 22 Sep 2016 22:34:02 -0400
wrote:

On Thu, 22 Sep 2016 14:07:34 -0400, Leon Fisk
wrote:

snip
I welded up a neighbors broken grass shoe earlier this summer for his
JD #5 Sickle Mower. It was in two pieces and had already been
welded/fixed a long time ago. Cast iron, never tried welding that
before. I bought some Forney Noma-Cast rod to try. Nickle rod is just
way too expensive for my fooling around abilities...

So far it has held together for at least one mow job. I had my doubts
it would even last that long ;-)

A friend and I have had good results welding cast with stainless
steel mig wire - using TIG and pre-heating the heck out of it. Have
had very good results on cracked exhaust manifolds, as well as cast
depth control sector on old John Deere tractor. Several of the
repaired parts are over 10 years old in regular use.

Clare, thanks for the tip. I'll add it to my welding cast iron notes.
Stainless filler rod has around 10% nickel depending on the type. Quite
a bit more chromium. I'm sure the nickel is helpful. This is where the
metallurgy education would be of use. What does the chromium do, help
or hinder the weld...
No idea if the chromium helps or hinders - I just know it has worked
very well for me.

Chromium in cast iron acts as a carbide stabilizer, so I doubt it has
any bad effect on the weld when used as an alloy in the filler rod.
In cast iron it also reduces free graphite. Again, likely can't hurt

I have never welded cast iron, but I've read a lot about it for
article research. So this is second-hand info.

In general, austenitic stainless has two virtues for welding other
materials: it's ductile, and because it's austenitic, it can absorb a
lot of carbon from the base metal (c.i. is loaded with it) without
becoming brittle.

This has led a lot of people to use stainless filler for welding c.i.
The 309 and 309L grades seem to be preferred. But when experts comment
on it, they often say it's something you "can get away with," and it's
not as effective or as reliable as high-nickel filler metals made for
welding c.i.

--
Ed Huntress