On Sat, 31 Dec 2005 17:22:35 -0800, "Harold and Susan Vordos"
wrote:


"Wayne Cook" wrote in message
.. .
snip--

I'm afraid I'll have to disagree at least a little in this
statement. I actually believe that 4140 was developed to be a high
strength material that could be welded reliably.


Oh, yeah! It's not that it can't be welded, but more so that when folks
like us weld on it, we're asking for cracks or other problems. When
it's welded to MIL specs, how it's handled is ultra critical, and must see a
heat treat oven in short order.

Just a caution that welding on it like it's mild steel can yield certain
surprises, including a weld so hard you can't do anything with it if
necessary, aside from grinding. Hell, you can weld cast iron with
7018------it just doesn't turn out too well.

Note that I didn't say it was without problems. Note also that I
stated "reliably". It can be darn hard to get a reliable weld in most
other high carbon steels. I'm not trying to be confrontational about
this (I even started to not respond to this since it's just things
like this that start the wars that are making this group less than it
was when it started).

I just stated that with a low hydrogen process and attention to not
cooling it to quickly (don't dunk it in water), and preferably some
preheat in the piece it's very possible to make a strong weld in 4140.

As for the machining I said flat out that it tends to get pretty darn
hard if not treated properly after the weld. Several times in that
post IRRC.

As for cast iron I'm of the opinion that there's nothing that will
replace brazing. I don't even use nickel rods unless I'm force to for
some reason or another.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm