4130 Chromoly vs. Reynolds 853 Steel

[Bobinator]

Can any of you explain the diffrence between the various steels used
for bicycles and their comparitive advantages? Example: A Lemond
Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as
though all of the steel recumbents are 4130 chromoly. Thanks in
advance.

[R2D2]

Bobinator wrote:
> Can any of you explain the diffrence between the various steels used for
> bicycles and their comparitive advantages? Example: A Lemond Zurich (DF)
> boasts a Reynolds 853 sticker on the frame. It seems as though all of
> the steel recumbents are 4130 chromoly. Thanks in advance.

853 has a higher strength to weight ratio, has better fatigue strength
and stiffness (about 30% greater than 4130). 853 is still Reynold's best
steel. The joints actually gain strength as they cool. 853 cannot be
brazed, only welded.

Reynolds makes a 4130 called Reynolds 525. It's a general all-purpose
tube - less expensive than 853.

R2







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[rorschandt]

(Bobinator) wrote in
m:

> Can any of you explain the diffrence between the various steels used
> for bicycles and their comparitive advantages? Example: A Lemond
> Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as
> though all of the steel recumbents are 4130 chromoly. Thanks in
> advance.
>

IIRC,most Reynolds steels use manganese as the stiffening alloy, although
they do make a 4130. 4130 uses chromium and molybdenum. Butted tubing is
more difficult to come across in larger diameters and lengths that are most
oft used in bents. Straight gauge 4130 is readily available.Also, many
alloys have more stringent temperature restrictions for brazing or welding.
4130 is more forgiving than most. Reynolds 853 is recommended to be used
with lugged construction silver brazed methods. Recumbent lugs are a
bit difficult to find.(^: Here is more info on the subject, written by
people who know much more than I:

A good description of Reynolds tubings:
http://www.worldclasscycles.com/JACKSON-HOME.htm
and
http://www.desperadocycles.com/The_Lowdown_On_Tubing/About_Steel_Tubing_pag
e4.htm

and http://www.henryjames.com/tubing.html
and
http://www.phred.org/~josh/build/brazing.html
and http://www.waterfordbikes.com/models/const.php

happy trails,
rorschandt

[S. Delaire \Rotatorrecumbent\]

The reason recumbents are done in 4130 is that a the tubing shapes and
sizes of a diamond frame bike do not cross over to a recumbent... yet.
Diamond frame tubes are usually no longer then 2 feet. Some recumbent
frames require 4 foot lengths.
Diamond frames are fairly routine in their dimensions. In many cases,
paint is all that makes one brand different from another.
In recumbent land the frames are very different from one maker to the
next. Change the paint and you will still know where the frame came
from.
4130 is good, strong material that comes in many sizes and shapes.
Perfect for the small manufacture.
Speedy

Bobinator wrote:

> Can any of you explain the diffrence between the various steels used
> for bicycles and their comparitive advantages? Example: A Lemond
> Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as
> though all of the steel recumbents are 4130 chromoly. Thanks in
> advance.



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[rorschandt]

(Mark Stonich) wrote in
om:

> rorschandt > wrote in message news:
>
>> Reynolds 853 is recommended to be used
>> with lugged construction silver brazed methods.
>
> DEFINITELY NOT!!!! See; http://www.reynoldsusa.com/prop/853.html
> where you will see that silver brazing is on Reynolds' list of "Tips
> on what you MUST NOT do with Reynolds 853"

Can't really argue with the Reynolds website! I don't know where I got the
silver part(sorry!), but the rest is just quoting from the Bob Jackson
website:
"The main advantage of Reynolds 853 is its ability to air harden after
joining, a characteristic not shown by other chrome molybdenum / manganese
molybdenum materials presently on the market. When building frames using
either TIG welding or high temperature brazing, above 1600 degrees, the
joints increase in strength as the frame cools to room temperature.

LUG CONSTRUCTION IS THE PREFERRED METHOD OF JOINING 853. It allows a much
larger area to be heated than tig welding which concentrates the heat to a
very small area at the weld. This completely goes against the “AIR
HARDENING” building philosophy of the material and adds nothing to the
strength of the joint. It is however a much cheaper joining method,
requiring less time and skill to perform."

I'm unlikely to be using the stuff myself. For now, 4130 crmo and 6061 and
7000 series aluminums serve my purposes fine. I have used chunks of heat
hardening steels for other machined parts, not on frames. I wonder how they
control the distortions in a "air hardened" tube?

rorschandt

[RoyG]

FWIW, interesting comment I saw posted recently on steel tubing:

"725 is Reynold's replacement for 753, it was introduced 4-5 years ago. It
is a Chromium-Molybedenum steel alloy that is heat-treated. Its non
heat-treated brother is 525 which is also the 531 replacement. 725 is a very
desirable tubing, said to be nearly identical to the famous but sadly gone
Tange Prestige tubing. Biggest advantage versus 753 is its heat tolerance.
Its low carbon content makes 725 easily joined with silver, brass or even
TIG welding, although it does suffer some annealing in heat effected area.
Most importantly for ride and durability, 725 has much better elongation and
ductility than air-hardened alloys thus maintains much of that resilience
that tubesets like 531 and 753 were most noted for. I would avoid 853/653,
Columbus Foco/Ultra Foco, Dedacciai 16.5 and True Temper OX Platinum/Gold --
these are in my experience rather "harsh or brittle" to borrow your
phrasing."


"Bobinator" > wrote in message
m...
> Can any of you explain the diffrence between the various steels used
> for bicycles and their comparitive advantages? Example: A Lemond
> Zurich (DF) boasts a Reynolds 853 sticker on the frame. It seems as
> though all of the steel recumbents are 4130 chromoly. Thanks in
> advance.

[Dave Larrington]

FWIW the frame of the late lamented Kingcycle was made from custom-ovalised
plain-gauge 531.

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
================================================== =========
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
================================================== =========

[Jim Plaia]

General rules of metallurgy:
Stiffness is a function of elastic modulus. Just about all steel
alloys have similar enough moduli that any difference would vanish
into the noise.

One should almost NEVER weld heat treatable steels, or any other heat
treatable alloy for that matter, unless you are prepared to re-heat
treat or accept the loss of strength in the base metal next to the
weld joint. The weld may meet the strength of the original base metal
but the heat from the welding will completely mess up the heat
treatment of the base metal next to the joint. Furthermore in thick
sections, nothing in bike manufacture is thick enough for this
concern, it is required to heat the metal to red hot to prevent
cracking of the base metal next to the weld joint. (Personal lesson
learned here is to never simply tell someone to get the joint hotter
than hell before welding unless you tell them how hot you think hell
is.)

Fatigue resistance and actual tensile strength is a function of the
alloy, but it is also a function of the heat treatment. Also, the
fatigue resistance of steels is relatively high. Minor changes can
seriously affect the fatigue properties of aluminum alloys because it
is is much lower, but steel is relatively tolerant. I'm not sure if
you'll see any real differences here in a practical, rather than
laboratory, situation.

If there is any real differences, you might see some effect in
corrosion resistance. An alloy that is tweaked to the limits of what
it can do will corrode faster than one that is working in the center
of its capabilities.

4130 Cr-Mo steel is used frequently because it is an old
well-characterized alloy. It's commonly available, easy to
manufacture, and in the kinds of section thicknesses you see in bikes,
easy to heat treat. If you were willing to pay what it cost to make a
custom titanium bike and end up with a steel bike, I could suggest
some better steel alloys that, if you were the kind of rider that
Fabrizio thinks he is, you might be able to detect the difference in
performance.

From a basic metallurgy standpoint only, the differences in alloys
means they can charge you more money because they use their "custom"
alloy rather than garden variety 4130. Racing strips would be about
as effective.

[Tom Sherman]

R2D2 wrote:
> ...
> Because the air-hardened joints Increase in strength after welding, the
> overall stiffness of the frame is increased substantially (30% greater
> than 4130 Chrome-Moly is typical). I'm talking about a built frame here,
> not raw tubes. This is of course due to the fact that the 4130 joints
> will become annealed during the joining process. Now some may argue that
> the ride of a frame built with un-heat treated steel is much more
> forgiving (softer), and thus preferable.

The increase in strength at the joints will not effect elastic modulus
significantly. You are confusing two different things here. It would
take precision equipment to measure the difference in elastic modulus
between Reynolds 853 (before or after heat treatment) and 4130 Cro-Moly.
In practical terms there is no difference.

> I'm not saying that an 853 frame is ultra-stiff by any means. My
> aluminum DF Klein MTB would be considered ultra-stiff. Klein heat treats
> the entire frame post welding. The energy transfer from pedal to wheel
> is simply amazing.

This has to do with the size and wall thickness of the tubing and the
frame geometry - heat treating the frame after welding affects tensile
strength but not elastic modulus.

> Jim's advice here pertains to un-heat treated tubes (like the 4130s),
> and not the heat-treated 853....

Jim is correct about there being no appreciable difference in the
elastic modulus of the two steels.

Tom Sherman - Quad Cities USA (Illinois side)

[Jim Plaia]

First before I say anything, I've just had knee surgery to correct a
problem with my knee that's prevented me from cycling for about 10
years and I'm only on the newsgroup because my wife's about to buy a
Streetmachine. Now that I've admitted to having no credentials at all
about frame building, discussions on this this newsgroup seem to imply
that the frame performance is mostly based on stiffness. Once the
frame is strong enough to deal with the abuse life throws at it, a
stronger frame is unimportant. The stiffer a frame gets the more
cycler power can be applied more efficiently (I realize that there was
a discussion about having too stiff a frame).

If I'm correct about that, frame stiffness is again a function of
modulus and does not include tensile strength at all. All steels from
1020 plain carbon steel to the special through harndening tool steels
have close enough moduli that you day to day variation in cycling will
swamp the small change in cycling performance. Tensile strength is
only important when that cyclist hits a bump/curb/car/etc and it's
time to decide how badly the bike gets bent.

Second question, titanium and aluminum are rarely selected because of
their strength to weight ratios. They tend to be cited for their
excellent stiffness to weight ratios. If you are not constrained in
tube thickness, titanium or aluminum alloys can match the stiffness of
a steel bike with a fraction of the weight. The also tend to have
tend to have shorter fatigue lives and fun corrosion modes (if it's
fun for the metallurgist, it's not fun for the user). Saying that a
steel has the same strength to weight ratio as titanium is nice, but I
still think that stiffness(modulus) is the driving property and there
isn't a steel in existence that matches aluminum or titanium in
modulus to weight ratio.

I'm probably not going to change anyone's mind, but I'll give the
official metallurgy party line: Don't weld heat treatable steels
without giving them a post-weld heat treatment or understanding the
loss of strength caused by welding. The base metal isn't simply
annealed. The base metal has melted next to the weld joint (melting
the base metal is the definition of welding rather than brazing).
That metal has now converted to martensite; really strong and really
brittle. The base metal that didn't melt but is next to the weld is
fully annealed and likely to be dead soft for the base metal. The
area that didn't get fully annealed is over-tempered and much weaker
then it should be, and so on out from the weld until you reach
unaffected base metal. There are ways to get a mechanically
reinforced joint so this doesn't matter, but welding on a heat treated
steels is generally a bad idea.

[Mark Stonich]

(Jim Plaia) wrote in
> If I'm correct about that, frame stiffness is again a function of
> modulus and does not include tensile strength at all.

The desirable types of stiffness in a bike frame come from
increasing rigidity in bending and torsion. These increase rapidly
with increases in diameter. Higher tensile strength steels allow
higher diameter to wall thickness ratios. OX Platinum is available in
1.375" diameter that is only 0.016" thick between the butts. In 4130
such a tube would dent or buckle too easily to be practical.

> there isn't a steel in existence that matches aluminum or titanium in
> modulus to weight ratio.

Steel and Aluminum have almost identical modulus to weight ratios.
Steel's is pretty constant. Aluminums have some variation but the
average is about the same as steel. Titanium lags well behind at
about 87% of steel. Aluminum will build a stiffer frame for a given
weight, only because you can use larger diameters.

Example; If an aluminum tube has a 20% larger OD can have walls twice
as thick as a steel one, for dent and buckling resistance, and still
be 11% stiffer yet weigh only 82% as much.

If OD is constrained, steel wins, as the extra bulk of the aluminum
is closer to the middle of the tube where it is less effective.

Don't get me wrong, I've no desire to move into exotic steels, Al, CF
or Ti. I built a 4130 frame with a 60" wb that weighs 4.5lbs. and is
stiff as granite against pedalling forces, yet nicely compliant
vertically. An Al frame with this much vertical flex would fail rather
soon IMHO.

BTW True Temper has found that their non-air hardening, heat treated
steels retained a higher percentage of their strength after welding
than their non-HT tubes.

[R2D2]

Mark Stonich wrote:
> Don't get me wrong, I've no desire to move into exotic steels, Al, CF or
> Ti. I built a 4130 frame with a 60" wb that weighs 4.5lbs. and is stiff
> as granite against pedalling forces, yet nicely compliant vertically. An
> Al frame with this much vertical flex would fail rather soon IMHO.

Kudos Mark on the great frame!

My attempt at a 66" LWB weighed in at a full 6 lbs. I have nowhere near
enough experience to start pushing wall thicknesses or shaping. I guess
I'll just keep being conservative until I can find a Mentor.

I agree, vertical compliance is a pretty high priority with these
babies. R2






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[Mark Stonich]

R2D2 > wrote in message news

>This unique
> air hardening property of Reynolds 853 provides additional stiffness
> through reduced micro yielding at the joints, allowing stiffer frames
> with excellent fatigue strength (when compared to standard chrome
> molybdenum) and excellent ride quality."

Well that settles it then. Alloying and heat treatment CAN alter the
modulous of elasticity of steel. This sentence, written by some
advertizing flack, ovbiously disproves the results of more than 200
years of metallurgical science and many, many thousands of tests. Just
think of all the textbooks that will have to be re-written. The
implications for spring design alone are enormous.

[R2D2]

Point well made guys. Thanks for persevering (darn advertising hacks!)

R2



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