"Ed Huntress" wrote in message
...
On Fri, 23 Jun 2017 10:49:28 -0400, Tom Gardner
wrote:

On 6/22/2017 5:11 PM, Terry Coombs wrote:

One of the locals brought me a part from his brush hog , it's
the
pivot yoke that carries the rear wheels (I think) . The sleeve
that fits
it to the pivot pin on the body of the machine is worn , and had
broken
the weld on one side , sleeve was split most of the way up .

I'm machining him a sleeve from some 4140-type
(acts/welds/spark
tests/hardens just like 4140 but ...) and I will be welding it to
the
angle iron frame of the yoke . I can either arc weld it with 7018
or
6013 or I can TIG weld it with ER70S2 (or 308 or 309 SS) - my
baby MIG
ain't got the ass for something this heavy . I know they TIG
4130/4140
tube for chassis's , but that's a lot thinner cross section . This
part
will be ~1.250" ID x 4.5" long with about a .625 wall thickness ,
the
original had a 3/16" wall . I don't want to have this thing fail
because
of a HAZ failure ... I'm thinking I might need to preheat (after
tacking
in place) then control cooling to avoid localized hardening .
Thoughts ,
opinions (about the job!) your experiences in the same/similar
situation
welcomed . If you think I'm an idiot for taking this on , keep it
to
yourself ...

--

Snag


I might be tempted to braze it.

Brazing would work. Welding any 4130/40 that thick is going to need
pre-heat and, probably, post-heat.

Here's an article on welding 4130 that we published last year. It
took
me a year to squeeze this article out of the experts. I was
frustrated
for years by the vast amount of bull that's been published about
welding 4130, and I finally got to the right guy at Hobart:

http://magazine.fsmdirect.com/2016/sept/d/#page7

--
Ed Huntress

Thanks. That's similar to advice Finch gave in Performance Welding.