Aermet as a frame material
Douglas R. Brooks
I have the opportunity to obtain a frame made of
Aermet (apologies if the spelling is incorrect, but
if you know what I am talking about then you are the
person I want to hear from!). I know there was a thread
about this some time ago (Gary Helfrich, et.al.) but,
of course, didn't pay close enough attention.
So my query is about what this steel-like/composite(?)
stuff is, if it is a durable material, and what its characteristics
might be.
The frame in question comes from a reputable, well-known
company and is a "prototype" manufactured for them by an
equally reputable small frame builder. The warranties of this
company still apply.
Any MaterialsGurus who would like to offer _any_ opinion
on the suitability of Aermet for bike frames is welcome
to email me personally, especially if you'd rather not post.
Thanks to all in advance!
Douglas Brooks
db...@troi.cc.rochester.edu
Andrew MacNaughton
I'm not a guru, and this is based on a review I read recently.
Aermet is a very hard, fairly stiff steel that is difficult and
expensive to work. Light weight because of the strength, but (so far)
may not be available in butted tubes.
Gary Helfrich
Aermet is a very high strength steel, not a composite material. The
mechanical properties are about as high as they get for steel, and
still have a ductile material.
Aermet is still an iron based alloy, so the modulus (stiffness) is not any
higher than any other iron alloy. The high strength and endurance limit
cannot be exploited to their full potential because of this fact. The
wall to diameter ratios would be so high that any local buckling would
result in catastrophic failure. Try this experiment some time for a good
example of this: Stand VERY CAREFULY on an empty beer can. Even though
the wall of the can is less than .2mm, it will support a large adult if
the person is careful enough when they stand on it. Take a pencil and
poke the side of the can while your buddy is standing on the can.
For the above reason, Aermet is not availble in tubes with less than .5mm
wall, or in diameters over 1.25 inches. There is also no butted or
tapered tubing available. The limited selection of tubing walls and
diameters restricts the design process, which in turn will compromise the
performance of the frame. Aermet will rust just like other steel bicycle
tubing. If the wall were much thinner, corrosion would be a big problem.
It does not take that long to loose a tenth of a millimeter to corrosion.
Gary Helfrich
Arctos Machine
Kristan Roberge
lap...@wco.com (Gary Helfrich) wrote:
>
> Aermet is a very high strength steel, not a composite material. The
> mechanical properties are about as high as they get for steel, and
> still have a ductile material.
There is a classified alloy in Carpenter's list of steels known as...
AF1410 / High Carbon AF1410 that Aermet100 is a suggested substitute
for, and it would be interesting to find out if its stronger/tougher
than Aermet. The following is copied from their website...
Single Figures are Maximums
0.17 or 0.20 C, 0.10 Mn, 0.10 Si, 0.003 P, 0.001 S, 10/10.30 Ni, 14.2/14.40 Co, 1.0 Mo, 2.0
Cr, Bal. Fe
This alloy is available only in the United States to DOD approved/funded projects. Please contact
your nearest Carpenter service center for more details. (AerMet® 100 alloy may be considered as
a substitute for AF1410, without restrictions.)
>> For the above reason, Aermet is not availble in tubes with less than .5mm
> wall, or in diameters over 1.25 inches. There is also no butted or
> tapered tubing available. The limited selection of tubing walls and
> diameters restricts the design process, which in turn will compromise the
> performance of the frame.
Actually its now available from Carpenter's special products division
in sizes from 5/8" diameter up to 1 3/8" diameter in 1/8" increments.
Wall thickness for all sizes is 0.02" except for the 1 3/8" which
is also available in 0.026" thickness.
> Aermet will rust just like other steel bicycle
> tubing. If the wall were much thinner, corrosion would be a big problem.
> It does not take that long to loose a tenth of a millimeter to corrosion.
In another section of the website, Aermet is described as being "stress-corrosion
resistant"... want to explain to the rest of us in plain english what
that means?!?
************
Oh, and I got this email from a framebuilder yesterday who's worked
with Aermet100... provides some more info on the stuff...
Date: Wed, 22 May 1996 14:03:59 -0400
From: Glen Johannesson <gl...@rdmcorp.com>
Organization: RDM Corp.
To: Krob...@magi.com
Subject: AerMet
X-URL: http://ww2.altavista.digital.com/cgi-bin/news?msg@18299@rec%2ebicycles%2eoff%2droad&aermet
I don't currently have access to newsgroups so pardon my e-mail...
I have built a frame with the 3 main tubes of AerMet 100. I have spoken with
and received information from Carpenter Technologies Special Products Division
and I am an Engineer.
AerMet 100 tubing is currently available in diameters from 5/8" to 1-3/8" in
1/8" increments. All the tubing is strait gauge with a 0.020" wall thickness
except the 1-3/8" which is also available in 0.026" wall thickness. All the
tubes are formed from rolled and welded sheets. They are ground smooth on the
outside. The weld is visible on the inside of the tubing.
Carpenter claims the following properties...(for the heat treatment given it's
bicycle tubing products at the factory)
Ultimate strength 300,000 psi
Yeild Strength 285,000 psi
Elongation 15%
Hardness 55 Rc
They also suggest a post weld, post cold set heat treatment at 200-350 Deg F for
at least 2 hours and no more than 16 hours. This is to restore some of the
strength in the HAZ of the Aermet 100. It is suggested that the weakest point
on an AerMet 100 frame will be in the HAZ of the 4130 fittings (BB shell etc).
With a hardness of 55 Rc the tubing is very difficult to work with. Normal HSS
cutting tools are almost useless and Titanium Nitride coated tools last a very
short time. I found that grinding the tube mitres and water bottle holes worked
very well. Don't look for butted tubing created by removing material on a lathe
any time soon. I found the tubing will deflect from the HSS cutting tip before
even a scratch was made.
Cold setting the frame after welding is not an easy process and requires an
incredible amount of force. To re-align the head tube of my frame after welding
required two people pushing on a 4 foot bar (approx 900 ftlb) causing a nearly
20 degree twist out of plane with the seat tube in order to remove a 0.020" in
4" mis-alignment. I'd like to see any other frame material take that kind of
force!
My 20.5" mountain bike frame is 3.67 lbs (unpainted, 3.83 painted) using a
1-1/4" top tube, 1-3/8" down tube, a 1-1/8" seat tube and Ritchey Logic WCS seat
and chain stays.
If you have any more questions regarding AerMet 100 contact Carpenter at...
http://www.cartech.com/ahome.htm
Or send me your questions and I'll try to answer them as best I can.
If you are interested in a custom AerMet 100 tubed frame contact Hugh Black at
True North (519)638-2391. He did my TIG welding for me.
Thanks for your time...
Glen Johannesson
Back-40 Bicycleworks
Waterloo, Ontario
da...@lehigh.edu
In article <4o1v3d$o...@news.istar.ca>, Kristan Roberge <Krob...@magi.com> write
s:
>lap...@wco.com (Gary Helfrich) wrote:
>>
>> Aermet is a very high strength steel, not a composite material. The
>> mechanical properties are about as high as they get for steel, and
>> still have a ductile material.
>
>
>> Aermet will rust just like other steel bicycle
>> tubing. If the wall were much thinner, corrosion would be a big problem.
>> It does not take that long to loose a tenth of a millimeter to corrosion.
>
>In another section of the website, Aermet is described as being "stress-corrosi
on
>resistant"... want to explain to the rest of us in plain english what
>that means?!?
>
the ASM Metals Handbook, Ninth Edition, Volume 11: A cracking process that
requires the simultaneous action of a corrodent and sustained tensile stress.
The classic case is cracking of brass in aqueous ammonia, discovered (I think)
in brass cartridge shells exposed to ammonia in hot, damp environments such as
the monsoons in India, and originally called "season cracking" for that
reason. The tensile stress in that case, and many others, was from residual
stress resulting from the severe forming operations in making the shell.
The corrosive environment in SCC is often one that would cause little or no
apparent corrosion by itself, so SCC can be unsuspected until sudden failure
occurs. That's why it can lead to disastrous results when a previously
unknown corrosion/material/stress combination is encountered.
For high-strength steels, aqueous chlorides--even road salts--can cause SCC,
even when corrosion is just superficial. That is one of several reasons that
steels are not often used at the highest strength levels that can be attained
by heat treatment; instead a lower strength level is obtained by tempering
following quenching in the usual heat treatment procedure.
Back to AerMet 100: It does corrode similarly to other steels. but Carpenter
claims that it has "exceptional resistance to stress corrosion cracking..."
This illustrates that SCC resistance can differ among similar materials, and
AerMet has presumably shown better resistance to SCC than many other steels in
the standard tests that are used, and possibly in specific operational
environments that have been tested. I doubt that this exceptional SCC
resistance is going to be important for bicycle frame applications, but who
knows........
This long discussion is mainly to emphasize the subtle and complex nature of
SCC in materials. It generally takes a research project to identify new SCC
situations, and that's how today's body of knowledge has been built up.
Dave Thomas, da...@lehigh.edu
Gary Helfrich
Kristan Roberge (Krob...@magi.com) wrote:
: lap...@wco.com (Gary Helfrich) wrote:
: >> For the above reason, Aermet is not availble in tubes with less than .5mm
: > wall, or in diameters over 1.25 inches. There is also no butted or
: > tapered tubing available. The limited selection of tubing walls and
: > diameters restricts the design process, which in turn will compromise the
: > performance of the frame.
:
: Actually its now available from Carpenter's special products division
: in sizes from 5/8" diameter up to 1 3/8" diameter in 1/8" increments.
: Wall thickness for all sizes is 0.02" except for the 1 3/8" which
: is also available in 0.026" thickness.
Twenty thousandths of an inch is still thicker than .5mm. The wall to
diameter ratio of the 1.375 inch tube is far from what would be needed to
exploit the extreme strength of Aermet. The specific stiffness of Aermet
is no better than mild steel. Seamless, butted Aermet is still not
available. For that matter, stress relieved Aermet tubing is not
available. Cut an Aermet tube along the weld longitudinally for some real
excitement.
There are loads of bicycle parts that Aermet would be the ideal material
for. BB spindles, cogs and chains all come to mind. As a frame material,
it is not much better than the current steels now being offered. It is
cool stuff, but 11 tooth cogs would be a better use for it than bike
frames.
Gary Helfrich
Arctos Machine
Kristan Roberge
lap...@wco.com (Gary Helfrich) wrote:
> There are loads of bicycle parts that Aermet would be the ideal material
> for. BB spindles, cogs and chains all come to mind. As a frame material,
> it is not much better than the current steels now being offered. It is
> cool stuff, but 11 tooth cogs would be a better use for it than bike
> frames.
And if it wasn't such a bitch to machine you'd probably see it being used
for cogs, chains, chainrings, BB spindles, etc.
Gary Helfrich
Kristan Roberge (Krob...@magi.com) wrote:
I've never machined a female dog, but I would suspect that Aermet makes
less of a mess. Aermet for Tooling is an annealed version of the product
that is no tougher to machine than Ti-6Al-4V. BTW, I'm speaking from
actual experience, rather than parroting the Carpenter Technology web
site. Titanium's low machinability has not stopped it from being turned
into every bike part you could imagine, as well as a few that would be
good to forget about.
The advantage that titanium holds here is that distribution is not
controlled by a single company. Carpenter is not up to speed yet when it
comes to dealing with small commercial customers.
I've machined a few parts out of Aermet, and the most difficult thing was
obtaining the material. It seems to be a good substitute for A-2, which I
use for fixturing in my milling machine. It wears well, and does not
distort as much as A-2 when it is heat treated.
Gary Helfrich
Arctos Machine
Michael Chang
Tom Kellog (The guy who builds Merlin and Spectrum frames) had spoken
about frame materials at one of our club meetings and had said its
amazing stuff! He claims he was able to put a tube in a shop vise,
clamp it, and it springs right back. To bad its such a pain to work
with as we've been reading in the thread. I believe the DoD sought
out to see if such a material could be made for the Navy because the
tail hooks were snapping off some of the planes landing on carriers.
da...@Lehigh.EDU wrote:
>> Dave Thomas, da...@lehigh.edu
________________________________________
________________________________________
Michael and Kimberly Chang
Phoenixville, PA
USA
Email: Mich...@po.fast.net
Web: http://www.user.fast.net/~michaelc/index.htm
Phone: 610-983-9715
_~o
_ `\<;_
________(o) / (o)_________________________
________________________________________
Bruce Frech
Tom does not build Merlins, tho they claim to use geometry on
their road frames suggested by him. He used to build very nice
steel frames. He runs Spectrum and has many employees who cut
the tubes, braze or weld them, polish them, paint & so on. He
is now a businessman.
Michael Chang wrote:
>
> Tom Kellog (The guy who builds Merlin and Spectrum frames) had spoken
............................
LAM
Wrong.
Spectrum Cycles consists of 2 people: Tom Kellogg and Jeff Duser.
Tom designed the geometry on all the Merlin road models. He also assists
in designing many of the frames for the Merlin Made-to Measure Program,
as well as performing ALL the fit and design work for ALL of Spectrum's
custom frames(Ti and steel). As anyone who owns a custom bike knows,
frame fit and geometry design are the most important aspects of getting
a great frame.
Merlin welds/fabricates Spectrum's Ti frames to Tom's specifications.
Jeff Duser has been building Spectrum's steel frames for over 10 years.
He is one of the best in the business.
Tom is still a master framebuilder as the quality and correctness of his
frames are still his greatest priority. He's actually not a great
businessman....
Nelson Lam
Bruce Frech
LAM wrote:
.>
.> Bruce Frech wrote:
.> >
.> > Tom does not build Merlins, tho they claim to use geometry
on
.> > their road frames suggested by him. He used to build very
nice
.> > steel frames. He runs Spectrum and has many employees who
cut
.> > the tubes, braze or weld them, polish them, paint & so on.
He
.> > is now a businessman.
.> >
.> > Michael Chang wrote:
.> > >
.> > > Tom Kellog (The guy who builds Merlin and Spectrum
frames) had spoken
.> > ............................
.>
.> Wrong.
.>
.> Spectrum Cycles consists of 2 people: Tom Kellogg and Jeff
Duser.
.> Tom designed the geometry on all the Merlin road models. He
also assists
.> in designing many of the frames for the Merlin Made-to
Measure Program,
.> as well as performing ALL the fit and design work for ALL of
Spectrum's
.> custom frames(Ti and steel). As anyone who owns a custom bike
knows,
.> frame fit and geometry design are the most important aspects
of getting
.> a great frame.
.>
.> Merlin welds/fabricates Spectrum's Ti frames to Tom's
specifications.
.> Jeff Duser has been building Spectrum's steel frames for over
10 years.
.> He is one of the best in the business.
.>
.> Tom is still a master framebuilder as the quality and
correctness of his
.> frames are still his greatest priority. He's actually not a
great
.> businessman....
.>
.> Nelson Lam
Not to put Tom down, but he does not build frames anymore. We
usually include at least the brazing/welding (for steel frames)
as part of being a builder. So I would say he >>was<< a master
framebuilder.
This info is from a good friend of Tom's who sends the frames he
builds to Spectrum for painting.
Bruce Frech
Terminology. I consider a framebuilder someone who builds
frames. To me that includes using a torch (for steel). If Tom
does not do that then he is not the builder. You appear to have
a different meaning for 'builder'.
Perhaps I might call him a master architect. But I don't have
much knowledge of his skills at designing frames except what I
read. I try not to use superlatives regarding things I have
little knowledge of.
I have nothing against Tom. I have ridden with him and raced
against him since before he lost his voice. I have seen frames
he has built & frames from Spectrum and both show top quality in
all ways I could observe.
LAM wrote:
>
> Bruce Frech wrote:
> >
> > Not to put Tom down, but he does not build frames anymore. We
> > usually include at least the brazing/welding (for steel frames)
> > as part of being a builder. So I would say he >>was<< a master
> > framebuilder.
> >
> > This info is from a good friend of Tom's who sends the frames he
> > builds to Spectrum for painting.
>
...
> I don't think a "good friend of Tom's" would say he is no longer a
> master framebuilder.
Those were my words, not the friend. Remember my definition of
builder includes building. The friend just said that Tom no
longer builds frames.
...
> What do you have against Tom Kellogg? Which framebuilders do you like?
I like Peter Dreesens' work.
LAM
Bruce Frech wrote:
>
> LAM wrote:
> .>
> .> Bruce Frech wrote:
> .> >
> .> > Tom does not build Merlins, tho they claim to use geometry
> on
> .> > their road frames suggested by him. He used to build very
> nice
> .> > steel frames. He runs Spectrum and has many employees who
> cut
> .> > the tubes, braze or weld them, polish them, paint & so on.
> He
> .> > is now a businessman.
> .> >
> .>
> Not to put Tom down, but he does not build frames anymore. We
> usually include at least the brazing/welding (for steel frames)
> as part of being a builder. So I would say he >>was<< a master
> framebuilder.
>
> This info is from a good friend of Tom's who sends the frames he
> builds to Spectrum for painting.
I don't think a "good friend of Tom's" would say he is no longer a
master framebuilder. True, he does not fire up the torch to braze/weld
the tubes anymore(however, Jeff Duser is second to none); however pretty
frames are only part of the story. I don't think anyone in the
framebuilding business knows as much about frame fit and geometry design
as Tom Kellogg. As anyone who owns/rides custom bicycles knows, this is
the most important aspect of getting a custom frame from a master frame
builder.
Harvey S. H. Lam
Bruce Frech wrote:
>
> Terminology. I consider a framebuilder someone who builds
> frames. To me that includes using a torch (for steel). If Tom
> does not do that then he is not the builder. You appear to have
> a different meaning for 'builder'.
>
> Perhaps I might call him a master architect. But I don't have
> much knowledge of his skills at designing frames except what I
> read. I try not to use superlatives regarding things I have
> little knowledge of.
>
> I have nothing against Tom. I have ridden with him and raced
> against him since before he lost his voice. I have seen frames
> he has built & frames from Spectrum and both show top quality in
> all ways I could observe.
>
> LAM wrote:
> >
> > Bruce Frech wrote:
> > >
>
> > > usually include at least the brazing/welding (for steel frames)
> > > as part of being a builder. So I would say he >>was<< a master
> > > framebuilder.
> > >
> > > This info is from a good friend of Tom's who sends the frames he
> > > builds to Spectrum for painting.
> >
>
>
> > I don't think a "good friend of Tom's" would say he is no longer a
> > master framebuilder.
>
> builder includes building. The friend just said that Tom no
> longer builds frames.
>
> ...
>
>
So is Ernesto Colnago a master framebuilder or a master architech?
What would Tony Rominger and Abraham Olano say? I met Ernesto 3
years ago and it is clear he hasn't picked up a torch in years,
however his expertise and knowledge are sought after by many. Most
people would still consider him a master framebuilder. Tom Kellogg's
bikes are in the same league.
Nelson Lam
Bruce Frech
I stand by my words. Colnago is not a framebuilder by my
definition if he does not pick up a torch. Thus he is not a
master framebuilder by my definition. Perhaps we could survey
the group and find out how many would include building (for
steel frame = using a torch) as part of being a master
framebuilder.
I have no problems with you or anyone else refering to Tom or
Ernesto Colnago as a master framebuilder. The only reason I
brought it up is some people don't know that these people do not
'build' the frames, and that may be important to some.
Harvey S. H. Lam wrote:
........
> So is Ernesto Colnago a master framebuilder or a master architech?
.........
>
> Nelson Lam
Chris Neary
Is someone who no longer personally builds bikes still a framebuilder?
I'm reminded of the line from Evita: "They still call me admiral, thou
I haven't been to sea in years."
If Tom Kellogg decided to come out of retirement and build a few
frames, I'd ride it with pride. Wouldn't you?
Cheers,
==============================================================
Chris Neary
dia...@aimnet.com
"It doesn't get any easier - you just go faster" - Greg Lemond
==============================================================