4130 can't be OA welded?

Morgans wrote:

wrote in message
...

On Dec 28, 2:57 pm, wright1902glider wrote:

the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch.

--------------------------------------------------------------------------------

Pure bull****. Indeed, for the stresses encountered in bicycles
(which is what he's talking about) there are any number of BRAZING
compounds that yield joints stronger than than normalized 4130.

O/A does just fine airframes... and for bike frames.


I'm not sure where this all fits in, but most lightweight bicycle frames
have a reinforcing "lug" around the tubes at the joints. Are you talking
bicycles or motorcycles?


Yep.

And the tubes are sometinmes "stretched" to reduce weight,

and the connections are often brazed.

Go figer...


Richard

On Tue, 01 Jan 2008 21:54:48 -0800, Richard Riley
wrote:

On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
wrote:

On Dec 28, 2:57 pm, wright1902glider wrote:
the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch.
--------------------------------------------------------------------------------

Pure bull****. Indeed, for the stresses encountered in bicycles
(which is what he's talking about) there are any number of BRAZING
compounds that yield joints stronger than than normalized 4130.

O/A does just fine airframes... and for bike frames.

If brazing gives stronger joints that normalized 4130, why aren't we
brazing airframes?

(I'm not saying it's an incorrect statement - I know better than to
disagree with VD on something like this. I just figure there must be
a reason, like the brazing compounds are more expensive.)

It is not your standard brazing. It is "fillet brazing", using a much
stronger "spelter" than your standard braze. The process uses a gas
flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
through the liquid flux ). The flux in the flame is EXTREMELY
reactive, so the flame "scrubs" the joint, leaving little if any flux
behind. These brazed joints ARE stronger than the 4130 or 4140 base
metal.

The process was developed for and used extensively by small race car
chassis fabricators in England and the continent. Lotus is a good case
in point.

--
Posted via a free Usenet account from http://www.teranews.com

On Wed, 02 Jan 2008 13:22:24 GMT, "Blueskies"
wrote:


"Richard Riley" wrote in message ...
On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
wrote:

On Dec 28, 2:57 pm, wright1902glider wrote:
the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch.
--------------------------------------------------------------------------------

Pure bull****. Indeed, for the stresses encountered in bicycles
(which is what he's talking about) there are any number of BRAZING
compounds that yield joints stronger than than normalized 4130.

O/A does just fine airframes... and for bike frames.

If brazing gives stronger joints that normalized 4130, why aren't we
brazing airframes?

(I'm not saying it's an incorrect statement - I know better than to
disagree with VD on something like this. I just figure there must be
a reason, like the brazing compounds are more expensive.)


Won't withstand high temperatures?

Will withstand temperatures higher than anything attatched to the
airframe will ever withstand.

--
Posted via a free Usenet account from http://www.teranews.com

I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
joint fail (come apart) where a welded one would hold?




Dunno, Mongo.

I guess it would depend on how hot for how long.

But remember that it takes an acetylene flame to braze in the first
place.

If if gets that hot in the engine room, whether the mount welds hold or
not is probably going to be a secondary issue...

Richard

Its just gotta last long enough for me to get it on the ground ;-)

"clare at snyder.on.ca" wrote in message ...

It is not your standard brazing. It is "fillet brazing", using a much
stronger "spelter" than your standard braze. The process uses a gas
flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
through the liquid flux ). The flux in the flame is EXTREMELY
reactive, so the flame "scrubs" the joint, leaving little if any flux
behind. These brazed joints ARE stronger than the 4130 or 4140 base
metal.

The process was developed for and used extensively by small race car
chassis fabricators in England and the continent. Lotus is a good case
in point.


What is the melting point for the brazing material?

On Wed, 2 Jan 2008 06:40:47 -0800 (PST), "
wrote:

On Jan 1, 9:54 pm, Richard Riley wrote:


If brazing gives stronger joints that normalized 4130, why aren't we
brazing airframes?

(I'm not saying it's an incorrect statement - I know better than to
disagree with VD on something like this. I just figure there must be
a reason, like the brazing compounds are more expensive.)
-----------------------------------------------------------------------------

Dear Richard,

That's a good question but you're asking the wrong guy.

Also, it isn't just ANY brazing, it is a form of eutectic brazing
developed specifically for alloy steels, initially for use in military
weapon systems as a means of reducing the cost & weight of certain
structures. The components are cut very accurately on CNC equipment
and most of the joins were done in an oven with the parts secured in a
jig.

The only problem I can see with this method is that REPAIRS would be
rather difficult; certainly not as convenient as with an O/A torch and
wire coat hanger :-)

Dig through French's books. If he hasn't written something about it,
he should have.

-R.S.Hoover


You are referring to "furnace brazing" which is different than "fillet
brazing" (also known as braze welding)

see: http://www.henryjames.com/gasf.html
I believe they are generally a nickel silver braze.

--
Posted via a free Usenet account from http://www.teranews.com

Jim , if my memory serves me correctly , the Straw color that you are
referring to is called Tempering , if you would bring a piece of High Carbon
Steel like a chisel or other tool up to red color and quench it in oil , it
would be very hard and have very little ductility , the reheating or
tempering to what I remember was about 450 deg. would make the part more
serviceable and less likely to shatter , the cherry red that we use to
finish out our TIG welds has somewhat the same effect except that it helps
to bring the entire cluster back to the original 90 ksi and removes the
push-pull and strain that is locked in for 1000 yrs. or so.
Phil
"Morgans" wrote in message
...

"Charles Vincent" wrote

4130 is indeed hardenable by heat treatment or cold working. And 4135
even more so. I have hardened them both using both water and oil
quenches, though if you took the time to read one of the metallurgical
tomes on the subject, you would find they are spec'd as an oil hardening
alloy. Water has worked fine for me on small sections, though my
default quench (i.e. the bucket next to the forge) is water with a layer
of olive oil floating on the top. I used to use used ATF or motor oil as
it was cheap, but burning olive oil is more friendly.

After you harden it by quenching, do you then go though the normalizing,
by heating to "straw" color, and over a period of several minutes, remove
the heat, a distance at a time?

That was what I was taught eons ago, but only in reference to working mild
"God only knows" what type of steel. I'm talking in cars and trailers and
tractors and such.

I hear people talking about heating up the weld and tube to "cherry" and
that is not what I thought was the proper procedure, for normalizing. I
was taught that "straw" was attainable, by barely seeing any color in a
semi-dark area.

Can anyone straighten out my conceptions, and mis-conceptions, here? g
--
Jim in NC

You are referring to "furnace brazing" which is different than "fillet
brazing" (also known as braze welding)

see:http://www.henryjames.com/gasf.html
I believe they are generally a nickel silver braze.
-------------------------------------------------------------

Roger that. The original post had to do with bicycles, several
manufacturers of which use that method for fabricating the frames.

-R.S.Hoover

On Jan 2, 3:28 pm, "Phil" wrote:
Jim , if my memory serves me correctly , the Straw color that you are
referring to is called Tempering , if you would bring a piece of High Carbon
Steel like a chisel or other tool up to red color and quench it in oil , it
would be very hard and have very little ductility , the reheating or
tempering to what I remember was about 450 deg. would make the part more
serviceable and less likely to shatter , the cherry red that we use to
finish out our TIG welds has somewhat the same effect except that it helps
to bring the entire cluster back to the original 90 ksi and removes the
push-pull and strain that is locked in for 1000 yrs. or so.

Exactly. A cold chisel also has about 1% carbon in it. It's a
totally different thing than welding low-carbon steels.

Dan

On Jan 2, 1:42 pm, "Phil" wrote:
If you have any doubt as to the hardenability of any piece of steel , just
light up your TIG Torch and get it close enough to your steel specimen and
melt a small fly speck spot , turn off the welder and touch that spot with a
file , even on low carbon steel like 1018 you may find that the file will
give up just about as easy as the hardened 1018 will , hardness and loss of
ductility pretty much parallel each other , I have seen 4130 parts that
couldn't be filed or cut with a hacksaw , not good .

That applies to just about any steel with any arc. It has
something to do with the extremely intense heat and electron flow of
the arc. I spent years welding up broken castings and worn
crankshafts, and to avoid those hard start-spots (which crack easily
and play hob with the milling and turning cutters after welding) we'd
start the arc on a scrap bit of steel held against the part and run
off that onto the work. The only hard places after that were in the
transition zone, especially in cast iron, which has around 4% carbon.
You had to keep that zone as thin as possible, so we used nickel
filler and applied it a low amperage to minimize dilution of the
parent metal.

DAn