I also used to do some welding on nuclear subs. I was under the impression
keeping weld wire in ovens was to preserve the coating or shielding material on
the rod.
The only steel we used to preheat was HY-80 used on the pressure hull and
missile tubes. I was under the impression that the reasoning here was to
decrease
the temp differential during welding. All high tensile and mild steel were
welded
cold (and I mean cold here in Ct.)
Grant
50 Chevy 3100
52 GMC 150
Gene Davis wrote:
> Message-ID: <38A63127.7F41@tritel.net>
> Date: Sat, 12 Feb 2000 21:20:55 -0700
> From: Gene Davis <genedavis@tritel.net>
> Reply-To: genedavis@tritel.net
> Organization: Amoco Pipeline Co.
> X-Mailer: Mozilla 3.01C-KIT (Win95; U)
> MIME-Version: 1.0
> To: "G. Simmons" <gls@4link.net>
> Subject: Re: [oletrucks] Water from steel (was originally about POR-15)
> References: <001801bf75cf$b2a4fb60$0e76efd1@grantsim>
>
> G. Simmons wrote:
> >
>
> Hi guys, I dont know where the water comes from for sure, but would bet
> its atmosheric in origin. I used to weld for a living and know that if
> you want a good quality weld, especally on higher carbon steels, it is
> important you preheat enough (>/= 300F)to get this water out of the
> steel. Youve seen a welded piece break right next to the weld (called
> the heat affected zone) well, water makes this worse. Its called
> hydrogen embrittlement. The hydrogen comes from the water you see
> leaving the steel when you warm it. Using low hydrogen welding rod
> (E7018 for example) helps. Keeping your rod in a rod oven helps too.
>
> > >When you burn propane or acetylene or any hydrocarbon, the hydrogen
> > combines
> > >with oxygen to form water. It condenses on anything cool.
> > >2C2H2+5O2=4CO2+2H2O. 2 acetylene molecules combines with 5 Oxygen molecules
> > >to form 2 carbon dioxides and 2 water molecules.
> >
> > Hi Bob,
> >
> > I knew somebody smart could help us. Next question, though, is does this
> > actually mean that steel does not contain water? There are a couple of
> > peculiarities about the appearance of water during heating that look more
> > like water being drawn out than water being condensed.
> >
> > 1. The water only appears in the heated zone. You'd thing that if the
> > water was a condensate by-product of the gas, that it would condense more on
> > the cooler edges than in the heated middle.
> >
> > 2. The water appears at the beginning of the process and then disappears.
> > This is consistent with the idea that the heat is forcing out a finite
> > amount of water contained in the steel. If the water were coming from the
> > gas, wouldn't it be deposited at a constant rate instead of appearing only
> > at the beginning of the process?
> >
> > Of course, the steel may simply get too hot to allow further condensation on
> > its surface, but what I'm talking about can be seen with a torch pass or two
> > over the surface, which on a big piece of steel, doesn't put much heat into
> > the outlying areas, so there ought to be plenty of cooler areas to see the
> > condensation.
> >
> > Wish I'd paid more attention in school.
> >
> > Regards,
> >
> > Grant S.
> >
> > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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