The most common stainless steel alloy in fiber form is AISI 316L (Eu Norm 1.4404) part of the « Austenitic family »
It is intersting to compare it with the already good quality stainless steel composition of AISI 304, or with other fibers as AISI 601 alloy,( inconnel ) that has a very high content of Nickel:
Special alloy and stainless steel composition chart:
|AISI 316L EN1.4404||austenitic||0.03 max||2.00 max||1.00 max||0.045 max||0.03 max||12,5 / 14||17 - 18||2,5 - 3||reste|
|AISI 601 - Inconel type||-||-||-||-||-||-||61||24||al : 1||14|
|AISI 302 EN1.4310||austenitic||0,05-0.15 max||2.00 max||1.00 max||0.045 max||0.015 max||8/9,5||16/18||0,8 max||reste|
|AISI 304 EN1.4301||austenitic||0.07 max||2.00 max||1.00 max||0.045 max||0.03 max||8/10,5||18/19,5||-||reste|
|AISI 330Nb EN1.4887||ferritic||0.15 max||2.00 max||1 à 2||0.015 max||0.015 max||33/37||20/23||Nb 1 - 1,5||reste|
|AISI 630 EN1.4542||martensitic||0.07 max||1.00 max||0.7 max||0.04||0.03 max||3 - 5||15/17||0,6 max||reste|
|AISI 904L EN1.4539||austénitic||0.02 max||2 max||0.7 max||0,03 max||0,01||24-26||19-21||4-5||reste|
|Fe Cr Al - Fecralloy||Iron.Chrome.Alu||0.03||0,19||0.21||0,01||cu 0,05||-||20,51||al 5,85||reste|
The special alloys or stainless steel fiber behaviour in very high temperature environment will mainly depend of its Nickel and Chromium content and, to a lesser extend, to Molybden or other "rare earth".
One important factor, is also the generation on the fiber surface of different types of more or less protective oxydes, thanks to some catalytics components or rare earth.
therefore, by example:
The AISI 601 alloy will have one of the best performances in very high temperature environment because of its very hig content of NICKEL
Some FERRITIC alloys can also give good performances against oxydation in hig temperature environment because of their high percentage of CHROMIUM, eventually reinforced with rare earth as NIOBIUM by example for AISI 330nb.
FECRALLOY types, are also very intersting for gaz burners or catalytics applications by example.
A very important issue in high performance metallic fibers, is the processability of technical behaviour of the metal;
Generally, and to simplify,(!) more you have high percentages of nickel, chromium or Aluminium, in the alloy, better you will resist to oxydation, ... "BUT"... stiffer or more brittle becomes the material. This means, in flexible structures, that one must often make the best compromize between performance and long term flexibility! ... therefore the "well known" AISI 316L has still a promising future!
Fibers are much finer that human hair :
we measure the individual fiber diameter in microns (1/1000 of millimeter !)
Most conventional diameter are in between 6 and 30 microns ,
In TIBTECH, we work mainly with 3 main diameters: « 8µ, 12µ and 22µ. »
Fibers characteristics examples in the case of 316L
|Fibers diameter :||Electrical conductivity
|8 µ||170||7 – 8||1%|
|12 µ||80||17 – 18||1%|
|22 µ||30||55 – 60||1%|
* Warning : Tenacity and elongation at break are very much depending on the production process, (hard drawn or semi-annealed ratio). It also depends of the physical fiber cross section shape as well as weakness points due to crimping or other equivalent processes. Therefore some fibers can tend to be much more fragile of brittle and may lead in some case to micro fragmentation that could be dangerous in certain applications.
In the case of « Fractal fibers* », of stainless steel (this means with many micro and nano cavities so that much air is hold within the structure) , we can measure a theorical diameter corresponding to the equivalent of a conventional round section of the same quantity of stainless steel per meter. Another approach is to measure the « DRCM » well known in Wool Worsted industries.
* Ref of G.TIBERGHIEN’ conference at the M.M.F.C of dornbirn on behalf of UGITECH, about « fibres fractales » issued in « Chemical fibers international » magazine of the 6/2005
Source : Chemical Fibers International magazine, May 2005.
REMARK: The concept of stainless steel fractal fibers has been first developped by Mr Guillaume Tiberghien in 2004 when he was fiber activity director of the company UGITECH. He has made a paper in CHEMICAL FIBERS INTERNATIONAL followed by a conference in DORNBIRN.
The company "Kings Metal" who has taken over UGITECH' fiber activity in 2008, has asked us to remove this article from our web site, as it was making reference to one of their newly owned trade mark.