4130 can't be OA welded?

Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur and
for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C welding
was done with Oxy./Acet. until the 1960's , at that time it was found that
one could speed up production with TIG welding and the supply of skilled
Oxy./Acet. welders was drying up , I understand that the MIG process has
been approved for some time , a real shame that Oxy. has slowly been
eliminated from the A/C manufacturing , won't go into the HAZ , Thermal
Shock and loss of ductility thing as it is like religion and politics , it
always starts a fight , for all around reliability with respect to welding
4130 , I would place Oxy./Acet. at the top of my list and TIG and MIG as
second and last , Spirit Of St. Louis was Gas welded as was all of those old
J3's , T Craft's .
Happy New Year
Phil Lohiser
EAA 1273
"wright1902glider" wrote in message
...
While browsing a bit more of that "good 'ole internet wizdom", I ran
accross this page:

http://www.ihpva.org/com/PracticalIn...materials.html

Its a human-powered vehicle website, but on this page, the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch. Does this sound right? It was always my belief that
we've been OA welding airplanes out of the stuff for decades. Who is
wrong on this point?

Harry "I'm still stuck in the wood-age" Frey

I'm 100% confident that I can use O/A to produce a clean, void free weld in
4130 that is stronger than the surrounding metal. I can also do that with
TIG but I'm not as sure that the join is completely stress free. The
extreme heat from TIG is concentrated in a tiny area whereas the O/A torch
has heated the surrounding metal and effectively relieved the stresses.

That said, if I could afford TIG, that's what I would use. If stress
build-up bothered me, I could always stress releive by reheating and slow
cooling the weld with the old O/A torch.

Bill Daniels


"Phil" wrote in message
...
Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur and
for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C
welding was done with Oxy./Acet. until the 1960's , at that time it was
found that one could speed up production with TIG welding and the supply
of skilled Oxy./Acet. welders was drying up , I understand that the MIG
process has been approved for some time , a real shame that Oxy. has
slowly been eliminated from the A/C manufacturing , won't go into the HAZ
, Thermal Shock and loss of ductility thing as it is like religion and
politics , it always starts a fight , for all around reliability with
respect to welding 4130 , I would place Oxy./Acet. at the top of my list
and TIG and MIG as second and last , Spirit Of St. Louis was Gas welded as
was all of those old J3's , T Craft's .
Happy New Year
Phil Lohiser
EAA 1273
"wright1902glider" wrote in message
...
While browsing a bit more of that "good 'ole internet wizdom", I ran
accross this page:

http://www.ihpva.org/com/PracticalIn...materials.html

Its a human-powered vehicle website, but on this page, the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch. Does this sound right? It was always my belief that
we've been OA welding airplanes out of the stuff for decades. Who is
wrong on this point?

Harry "I'm still stuck in the wood-age" Frey

Bill: I recently did an article for our Experimental Helo magazine and did
some research on PWHT and found things like a minimum of 2hrs required @ 300
degrees C to adequately stress relieve a weld. All of the reports that I
read didn't think that the few tens of seconds of OA heating as a post weld
technique for stress relief was very effective. If you Google stress
relief of welded joints you will get a surprise. There has been a large
amount of testing and review of both pre-heat and post weld heat treatment
done on various materials complete with microscopic examination of the
affected areas. Further, Richard Finch, an EAA tech counselor and one time
head of Aerostar aircraft welding department said that 1800 Aerostar engine
mounts were all TIG welded without pre or post heat treatment. Records show
no cracking, while Fairchild Swearingen's Metroliners all had cracking
problems with TIG welded engine mounts that were both pre and post weld
heat treated. He did mention, however that the Metroliner mounts were TIG
welded with the copper coated welding rod common to OA welding. I know what
the "old timers" say about this but there doesn't seem to be much scientific
data to support the "old tried and true" method.

stu fields
Experimental Helo magazine.
"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..
I'm 100% confident that I can use O/A to produce a clean, void free weld
in 4130 that is stronger than the surrounding metal. I can also do that
with TIG but I'm not as sure that the join is completely stress free. The
extreme heat from TIG is concentrated in a tiny area whereas the O/A torch
has heated the surrounding metal and effectively relieved the stresses.

That said, if I could afford TIG, that's what I would use. If stress
build-up bothered me, I could always stress releive by reheating and slow
cooling the weld with the old O/A torch.

Bill Daniels


"Phil" wrote in message
...
Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur
and for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C
welding was done with Oxy./Acet. until the 1960's , at that time it was
found that one could speed up production with TIG welding and the supply
of skilled Oxy./Acet. welders was drying up , I understand that the MIG
process has been approved for some time , a real shame that Oxy. has
slowly been eliminated from the A/C manufacturing , won't go into the HAZ
, Thermal Shock and loss of ductility thing as it is like religion and
politics , it always starts a fight , for all around reliability with
respect to welding 4130 , I would place Oxy./Acet. at the top of my list
and TIG and MIG as second and last , Spirit Of St. Louis was Gas welded
as was all of those old J3's , T Craft's .
Happy New Year
Phil Lohiser
EAA 1273
"wright1902glider" wrote in message
...
While browsing a bit more of that "good 'ole internet wizdom", I ran
accross this page:

http://www.ihpva.org/com/PracticalIn...materials.html

Its a human-powered vehicle website, but on this page, the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch. Does this sound right? It was always my belief that
we've been OA welding airplanes out of the stuff for decades. Who is
wrong on this point?

Harry "I'm still stuck in the wood-age" Frey

"Stuart & Kathryn Fields" wrote in message
.. .
Bill: I recently did an article for our Experimental Helo magazine and
did some research on PWHT and found things like a minimum of 2hrs required
@ 300 degrees C to adequately stress relieve a weld.

Back in the early '60s I worked in the pipefitting shop at Todd shipyards.
Along with the repair work, we were building two new DDE's (Destroyer
Escorts). They were powered with steam turbines running 1500# of steam
pressure at 1000 degrees F. (or so).

The steam piping was Chrome-Moly tubing from 1" IPS (1.315" dia.) up to the
big 6-8" stuff. All of it was welded with TIG and then stress-relieved. We
had a dedicated area of the shop set up for that process. The pipes were
wrapped with asbestos sheeting followed by water-cooled electrical cables.
More asbestos was wrapped on top.

The cables were hooked to a large machine which sent alternating current
through them, inductively heating the piping within the coils. I don't
remember the temperatures or time involved, but they were recorded on chart
recorders. The process lasted many hours - even overnight IIRC. They were
heated to an initial, high temperature (700 F?) and then slowly cooled. The
records became a permanent official part of the piping's history and
pedigree - much like the documentation of aircraft components.

It was a job well-suited for the older, disabled steamfitters as it was
light work but demanded experience and meticulousness. There are few things
more scary than a cracked flange weld on a 6" high-pressure steam pipe at
sea. The escaping gas will easily slice a leg off at the thigh, cauterizing
the wound nicely.

Happy New Year!

Rich S.

Thanks Rich: That coroborates all the stuf I found thru digging thru
University research papers, certified welding instructors, Metalurgical
studies and a bunch of writings of people like you and the EAA tech
counselor. All that said, I have an IA friend that still insists on the OA
" normalizing" or "stress relieving" after a TIG weld. However, not on my
helicopter.
Stu
"Rich S." wrote in message
...
"Stuart & Kathryn Fields" wrote in message
.. .
Bill: I recently did an article for our Experimental Helo magazine and
did some research on PWHT and found things like a minimum of 2hrs
required @ 300 degrees C to adequately stress relieve a weld.

Back in the early '60s I worked in the pipefitting shop at Todd shipyards.
Along with the repair work, we were building two new DDE's (Destroyer
Escorts). They were powered with steam turbines running 1500# of steam
pressure at 1000 degrees F. (or so).

The steam piping was Chrome-Moly tubing from 1" IPS (1.315" dia.) up to
the big 6-8" stuff. All of it was welded with TIG and then
stress-relieved. We had a dedicated area of the shop set up for that
process. The pipes were wrapped with asbestos sheeting followed by
water-cooled electrical cables. More asbestos was wrapped on top.

The cables were hooked to a large machine which sent alternating current
through them, inductively heating the piping within the coils. I don't
remember the temperatures or time involved, but they were recorded on
chart recorders. The process lasted many hours - even overnight IIRC. They
were heated to an initial, high temperature (700 F?) and then slowly
cooled. The records became a permanent official part of the piping's
history and pedigree - much like the documentation of aircraft components.

It was a job well-suited for the older, disabled steamfitters as it was
light work but demanded experience and meticulousness. There are few
things more scary than a cracked flange weld on a 6" high-pressure steam
pipe at sea. The escaping gas will easily slice a leg off at the thigh,
cauterizing the wound nicely.

Happy New Year!

Rich S.

NASA published an advisory many years ago that was reprinted in Sport
Aviation , I don't have the article at my fingertips , as I remember , NASA
stated that any 4130 weld assembly that was TIG welded and used on Aircraft
should be post heated via Oxy/Acet , anyone who has ever done any welding
and especially ARC welding must know and has experienced the tension that
has built up after the weld has cooled , just a pinch of common sense would
tell you that this tension load will be there for the life of the weldment ,
to raise the temp. of a given cluster up to a point that allows that cluster
to seek it's sweet spot without that locked in tension and possible
premature failure would only make common sense , NASA is far from perfect
but they were on the money with this advisory .
I don't know how many people that write books on welding have actually
worked on the floor with real airplanes and have actually welded on
commercial airplanes , I have seen many lineal inches of Oxy/Acet weld laid
down and never saw a crack or fracture of that weld that occurred on the
floor even before an assembly was painted , I have seen many TIG welded
assemblies that would crack shortly after welding and again before they saw
paint , if you have an engine mount that needs a small amount of machining
and the machinist is damaging high speed steel end mills with hardened 4130
, this has to be very telling , it's been a few years since I worked for a
Jet engine repair station , as I recall , all welded parts were placed in a
oven and slowly raised to about 1020 Deg. F. and held at that temp. for 3
hrs. and then the temp. was dropped at a certain rate for several hours ,
they didn't do this for there own pleasure , this was FAA mandated .
Best
Phil Lohiser
"wright1902glider" wrote in message
...
While browsing a bit more of that "good 'ole internet wizdom", I ran
accross this page:

http://www.ihpva.org/com/PracticalIn...materials.html

Its a human-powered vehicle website, but on this page, the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch. Does this sound right? It was always my belief that
we've been OA welding airplanes out of the stuff for decades. Who is
wrong on this point?

Harry "I'm still stuck in the wood-age" Frey

"Stuart & Kathryn Fields" wrote

Thanks Rich: That coroborates all the stuf I found thru digging thru
University research papers, certified welding instructors, Metalurgical
studies and a bunch of writings of people like you and the EAA tech
counselor. All that said, I have an IA friend that still insists on the
OA " normalizing" or "stress relieving" after a TIG weld. However, not on
my helicopter.

So, do you think that the tig welding does not induce the stresses, and
therefore not need the quick OA "stress relieving" or what? I'm interested
in the reasons you came to this conclusion.

I may need to make cromolly engine mount, but the rest of my dreambuilt
airplane will not require any normalizing.

I hear wood airplanes do very poorly with an OA torch held at their
"clusters." ;-)
--
Jim in NC

Morgans: According to everything I read in my research for the article I
wrote, the "Quick stress relieving" by the few seconds of OA after a TIG
weld do not effectively relieve the stress and can actually cause a
weakening of the weld joint. There appears to be quite a bit of truly
scientific experimentation to support this view. As a retired engineer, I'm
more prone to accept the scientists report over the anecdotal evidence from
more questionable sources. All that said, I can relate to failures that I
saw as the result of a crash of Chrome Moly airframe. Tube failures near a
cluster showed a separation that occurred just a short distance (1/4") from
the weld that was relatively clean and very even and roughly resembling a
fatigue failure zone. The Richard Finch that I referred to in an earlier
post wrote the book called Performance Welding and cited his experience at
Aerostar. I'm going with him and his belief supported by the research I did
and will not allow an OA torch near my TIG welded joints.
BTW, with the exception of some welds on my SS exhaust, none of my TIG welds
which includes fuel and oil tanks and the SS railing on a 35' Sailboat have
shown any cracking. None of these had OA "Stress Relief".

Stu
"Morgans" wrote in message
news

"Stuart & Kathryn Fields" wrote

Thanks Rich: That coroborates all the stuf I found thru digging thru
University research papers, certified welding instructors, Metalurgical
studies and a bunch of writings of people like you and the EAA tech
counselor. All that said, I have an IA friend that still insists on the
OA " normalizing" or "stress relieving" after a TIG weld. However, not
on my helicopter.

So, do you think that the tig welding does not induce the stresses, and
therefore not need the quick OA "stress relieving" or what? I'm
interested in the reasons you came to this conclusion.

I may need to make cromolly engine mount, but the rest of my dreambuilt
airplane will not require any normalizing.

I hear wood airplanes do very poorly with an OA torch held at their
"clusters." ;-)
--
Jim in NC

"Stuart & Kathryn Fields" wrote

I'm going with him and his belief supported by the research I did and will
not allow an OA torch near my TIG welded joints.
BTW, with the exception of some welds on my SS exhaust, none of my TIG
welds which includes fuel and oil tanks and the SS railing on a 35'
Sailboat have shown any cracking. None of these had OA "Stress Relief".
That's what I thought you were saying.

I've never heard of these kind of studies before (that doesn't mean much)
but it seems pretty clear.

I'm surprised the heat of a tig weld are not worse on the frame, with the
small concentration of heat provided by that type of welding. The evidence
does make a strong case for that being true, though.
--
Jim in NC

Phil: The stress relieving that you described: of slowly raising the
temperature to1020 Deg. F and holding it for 3hrs then dropping at a certain
rate is certainly different than heating to cherry with an OA in less than a
minute and then letting it cool in less than a couple of minutes. The guy
I referenced in an earlier posting was responsible for the TIG welding of
1800 Aerostar engine mounts that did not crack and had no post weld heat
treatment. That, while anecdotal and not a report of a truly scientific
examination of the weld joints using metallurgical techniques, does carry
some weight with me. Not to mention his survey of a group of airframe
manufacturers which included Piper and Mooney that were surprisingly, using
MIG with no pre or post heating. An awful lot of successful experience of
welded joints without OA "Stress Relieving".
BTW my Baby Belle gets trailered to a bunch of events every year and has in
excess of 125,000 trailer miles over roads that have set ELTs off and I have
never found a crack in any of the welded joints and this includes a 17' tail
boom that has a bunch of welded cluster joints and is not supported
anywhere but at the front end by 4-5/16 bolts in double shear. My ship is
one of at least 5 with high trailer miles and I've yet to hear of a cracked
weld joint. This is an accumulation of about 15years experience with these
ships.
I note however that these joints were designed with amateur builders in mind
and the frame and joints are not designed close to the ragged edge but have
a sufficient margin to allow for less than expert welders. E.g. the tail
boom is of 0.049 wall tubing where similar tubing on the Bell 47 is as small
as 0.025. There are a lot of contributing factors to a successful TIG
welded joint.
I know of no metallurgical research or experiments that prove the very quick
and uncontrolled OA "Stress Relieving" is an effective useful tool in
producing a successful TIG welded joint. In fact my limited research into
the metallurgical reports found reports of decreased tensile strength in the
material as the result of Post Weld Heat Treatment. I know that this is an
area of strong opinions and I'm sure that I will be digging into the
metallurgy of welded joint more as I feel like I've just barely got my nose
into an area that is much more complex than I thought.

Stu
"Phil" wrote in message
...
NASA published an advisory many years ago that was reprinted in Sport
Aviation , I don't have the article at my fingertips , as I remember ,
NASA stated that any 4130 weld assembly that was TIG welded and used on
Aircraft should be post heated via Oxy/Acet , anyone who has ever done
any welding and especially ARC welding must know and has experienced the
tension that has built up after the weld has cooled , just a pinch of
common sense would tell you that this tension load will be there for the
life of the weldment , to raise the temp. of a given cluster up to a point
that allows that cluster to seek it's sweet spot without that locked in
tension and possible premature failure would only make common sense , NASA
is far from perfect but they were on the money with this advisory .
I don't know how many people that write books on welding have actually
worked on the floor with real airplanes and have actually welded on
commercial airplanes , I have seen many lineal inches of Oxy/Acet weld
laid down and never saw a crack or fracture of that weld that occurred on
the floor even before an assembly was painted , I have seen many TIG
welded assemblies that would crack shortly after welding and again before
they saw paint , if you have an engine mount that needs a small amount of
machining and the machinist is damaging high speed steel end mills with
hardened 4130 , this has to be very telling , it's been a few years since
I worked for a Jet engine repair station , as I recall , all welded parts
were placed in a oven and slowly raised to about 1020 Deg. F. and held at
that temp. for 3 hrs. and then the temp. was dropped at a certain rate for
several hours , they didn't do this for there own pleasure , this was FAA
mandated .
Best
Phil Lohiser
"wright1902glider" wrote in message
...
While browsing a bit more of that "good 'ole internet wizdom", I ran
accross this page:

http://www.ihpva.org/com/PracticalIn...materials.html

Its a human-powered vehicle website, but on this page, the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch. Does this sound right? It was always my belief that
we've been OA welding airplanes out of the stuff for decades. Who is
wrong on this point?

Harry "I'm still stuck in the wood-age" Frey