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Stainless steel weakened by chlorine gas

I believe my stainless steel bicycle spokes have been weakened by chlorine gas. When I stored my bicycle for extended periods in the garage, the next time I used it the spokes just started breaking. Chlorine tablets for pool treatment were stored in the garage. I believe the Cl2 molecules must infiltrate the stainless steel creating stress points. I have extensive experience with bicycle wheel building and use and can't come up with an alternative explanation for the sudden deterioration of these wheels. I would appreciate any insight you can provide.

Edward Kemnitzer
- Naples, Florida, USA
2003

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2003

Sounds like stress corrosion cracking (SCC) which you can research further on the Internet. This phenomenon affects certain high-strength metals in corrosive environments.

Bicycle spokes are made from cold-drawn wire of about 150,000 psi tensile strength. When installed, they may be tensioned up to about 50,000 psi. The combination of residual stresses in the metal from the initial drawing and the load stress make the wire susceptible to attack by chlorine and chloride, especially in a humid environment. As an analogy, consider cutting plastic film with a blade. The tighter the film is pulled taut, the easier the blade cuts.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.