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Old 03-13-2012
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Re: Chainplate reinforcement

Quote:
Originally Posted by Tafa View Post
Great point MedSailor... What do you think would cause the problem rust of metal exhaustion. If the main concern is rust, its easily inspect-able. Is there such concern as metal exhaustion on ss.

Thanks,

Tafa
Yes, the "metal exhaustion" you refer to is called "work hardening". When the stainless steel family of metals is flexed under load (anything other than a perfectly in-line load) it becomes more hard and brittle over time. It's a little counter-intuitive but it can actually become "stronger" with work-hardening but more brittle. Suffice to say the characteristics of the steel of your chainplates were selected for a reason at construction and hardening of them over time is bad. You don't want brittle metal with a shock load of a crash-jybe.

Reading on work-hardening here: Article: Mechanism and measurement of work hardening of austenitic stainless steels during plastic deformation

The type of corrosion that stainless suffers from is called "Crevice Corrosion" and it happens in an anaerobic environment. It's unavoidable with bedded stainless hardware. Silicone bronze (marine bronze) doesn't suffer from this problem but is more expensive and isn't "shiny" like stainless. Most of the time the corrosion appears as brown staining but unfortunately it's not always visible. Micro cracks on the surface can lead to destruction of the core of the chainplate with the only visible evidence being the (hard to find) micro-crack.

Reading on crevice corrosion here:http://soar.wichita.edu/dspace/bitst...pdf?sequence=1

Image of crevice corrosion on a chainplate:
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