From: Bernd.Kischnick@bbs.oit.unc.edu (Bernd Kischnick)
Subject: Re: Summ. of Frame Materials for Review
Summary: steel tubing table 
Keywords: steel tubes
Organization: Extended Bulletin Board Service
Date: Wed, 2 Sep 1992 16:29:54 GMT

From "tour Sonderheft Velo-Werkstatt III: Im Reich von Rohr und Rahmen" (1991)

Articles and table by Christian Smolik

listed properties:

ZF "Zugfestigkeit"
 Force needed to tear apart a solid wire of 1 mm^2 cross section.
 The more important value for constructing is the force to achieve plastic
 deformation; that's more or less proportional to ZF.
 But it's much easier to measure ZF.

BD "Bruchdehnung"
 Length you can pull a wire before it breaks,
 given in percent of the original length.

By varying the composition of an alloy and  --- more important ---
by a clever heat treatment the properties of steel can be anything between
- glass-like: ZF very high, up to 2000 N/mm^2; BD very low.
- rubber-like: ZF low, BD high.
For a bicycle frame, you would like to see both values as high as possible.

The other important value is the modulus of elasticity, commonly "stiffness".
But this is the same for all steel alloys. With steel elasticity=1,
you get: aluminum=0.3, titan=0.5, steel=1, carbon fibres=5--6.

The other values listed are the amounts of the various chemical elements
in the alloy, given in promille (parts per thousand).
+ means, yes, there is element X in the alloy, but I don't kow how much.
- means 0.
? means don't know nothing.
C, Cr, Mo, Mn, V and Ni are put into the alloy by purpose,
Si, P and S are normally regarded as dirt.

                ZF  BD   C    Cr   Mo   Mn   V    Ni   Si   P    S   
Mannesmann and others
25CrMo4        770  12  2.5   11   2    7    -    -    2   0.35 0.35
34CrMo4        870  12  3.4   11   2    7    -    -    2   0.35 0.35
Columbus
25CrMo4        800  17  see Mannesmann
Cyclex         900  15  2.7   2.7  2.5  11   1    -    2    ?    ?
Nivachrome    1100  15  3.4   11   1.9  7.4  1   0.3   2    ?    ?
Aelle          ?    ?    +    ?    +    ?    -    -    ?    ?    ?
Tange
CrMo4    911--1235  10  3.3   12   2.5  8.5  -    -   3.5  0.3  0.3
Mangaloy 735--950   10  0.8   -    -    22   -    -   0.3  0.2  0.7
Vitus
SM/Stone       800   7  1.9   -    -    14   1.3  -   3.6  0.2  0.05
XO/999         850   7  1.9   4.5  3    14   -    -   3.6  0.2  0.05
GTI/Olympic/
TXO/Rocky      900   7  1.9   5    3    15   1.3  -   3.6  0.2  0.05
Reynolds
531            695  10  2.5   -    2    13   -    -    2   4.5  4.5
501/500/453    802  10   +    +    +    ?    -    -    ?    ?    ?
753           1235   8   +    ?    +    ?    -    -    ?    ?    ?
Oria
HiTension      580   ?   +
25CrMo4        800   ?   see Mannesmann
34CrMo4        950   ?   see Mannesmann


Columbus tubesets ... are made of ... tubes:
MAX, EL - Nivachrome
Cromor, Gora - 25CrMo4
TSX, SL, SLX, SP, SPX, MS - Cyclex
Aelle - Aelle.

All Tange tubesets are CrMo4 except Mangaloy and MAngaloy-S.

Mannesmann, by the way, was the guy who invented the technology of
producing seamless tubes back in the 19th century and got quite rich 
during the following years --- but of course by producing weapons
(and locomotives), not cycle tubing :(

You see there is not that much variation in the alloys.
Most of the mechanical differences are the result of the heat treatment;
and this is the reason why some steels suffer so dramatically when
soldered too hot.


The myth of the aging tubing:

Like all myths, this one has but a tiny core of truth in it.
In fact nearly all of the  claimedly "aged" frames can be cured by painting.

The facts which caused the legend are:
1) A "renowned Italian high-end frame manufacturer" is accused of having
   produced bad solderings during several years. Analysis of weakened
   frames showed that on some of the muffs, only the third part of hte
   contact area was covered by the soldering material. After years of use,
   the remaining connection had broken and turned the soldered joint
   into a tight stick-in joint, which somehow weakens the frame...
   I read this story repeatedly in different magazines. They never told the
   name of the company, but from the context I would _speculate_
   it's Colnago.

2) A strong professional sprinter can kick hard enough into the pedals
   to produce a remaining plastic deformation of the rear stays of his frame.
   This is usually less than 2 millimeters and can't be seen,
   but it changes the bike's response to hard pedal strokes to an amount which
   makes it seem soft and wobbly to the tough guy who managed that.
   Reynolds thinks this problem is common enough to prevent it on their tubes
   (at least this is true for the 753 tubing):
   The tubes for the rear triangle get a different heat treatment,
   resulting in a very high ZF of about 1500 N/mm^2, whereas the BD is
   reduced (which doesn't matter that much on the rear triangle).

I hope this is enough to darken all remaining clarity :)

-   Bernd.

urgent email to bernd.kischnik@cdc2.ifum.maschinenbau.uni-hannover.dbp.de

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