Originally Posted by
CalTex
I am selling a Motobecane Super Mirage frameset with 2040 tubing. I would like to, at least, appear knowlegeable about the material when approached by prospective buyers. I have done exhaustive research on Google and can only find that it is "high tensile steel". Is there more that anyone has to offer as to the composition of this 2040 material, the frame construction, or even this frame as relates to Motobecane Super Mirages? If dating the frame is of use, there are pictures available at
http://www.doug-morgan.com/BikeSales/Motobecane.html and it came with a Sun Tour V-GT Luxe rear derailer and Weinmann center-pull brakes. Your assistance in this matter will be greatly appreciated.
2040 steel is a European Designation, and long outdated now...it was known for stiffness due to the high carbon content, and it also resisted heat hardening when brazed or welded, negating the need to anneal the frame after joining.
most other high carbon steel alloys readily harden when heated to a glow, then cooled.... hardened steel becomes BRITTLE steel... Brittle steel likes to Crack at high stress junctions.