Re: [CR]Stainless steel spokes and stainless steel in general


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Date: Tue, 30 May 2006 16:52:31 +0000 (GMT)
From: joebz@optonline.net
Subject: Re: [CR]Stainless steel spokes and stainless steel in general
In-reply-to: <002801c68400$e053e9e0$530a8351@com>
To: NIGEL LAND <ndland@btinternet.com>
References: <MONKEYFOODEfai5qX9R000019c5@monkeyfood.nt.phred.org>
cc: classicrendezvous@bikelist.org
cc: classicrendezvous@bikelist.org

I was resisting going into my probably all too familiar SS spoke rant. My opinion has long been that this was something of a wrong turn in material application. Because a bicycle spoke has high internal tensile stresses when drawn and is also necessarly subject to tensile stress when built in a wheel, it is a natural candidate for stress corrosion cracking. As Nigel suggests, bicycle spokes are typically made from 18/8 austentic steels that are subject to corrosion cracking. As to the presence of sodium, very little will do. The infamous Robergel Trois Etoiles somehow chose an even worse alloy or process as they broke left and right.

When a given wheel starts breaking spokes four years after building- time for new spokes. I just wish high quality galvanized spokes were still available. Maybe they are? They are not as pretty, but, all in all, gave better service at a lower cost.

More on the cracking mechanism for the curious:

http://www.tpub.com/content/doe/h1015v1/css/h1015v1_134.htm

Joe Bender-Zanoni
Great Notch, NJ


----- Original Message -----
From: NIGEL LAND
Date: Tuesday, May 30, 2006 11:55 am
Subject: [CR]Stainless steel spokes and stainless steel in general
To: classicrendezvous@bikelist.org
Cc: cpotz@aol.com


> Steve, the thing is there are many different types of stainless

\r?\n> steel. It is

\r?\n> a family of alloys with very diverse properties. Most people

\r?\n> only come

\r?\n> across the most well know 18/8 versions, beloved of cutlery

\r?\n> makers. That is

\r?\n> an austenitic steel with 18% chrome and 8% nickel with other

\r?\n> elements that

\r?\n> denote the type of 18/8 - these are designated by AISI numbers -

\r?\n> type 316

\r?\n> being the best known, though the chrome is supposed to be 10-14,

\r?\n> so a bit of

\r?\n> an anomaly there. The next group is known as ferritic stainless

\r?\n> and these

\r?\n> steels have between 12 and 27% chromium, no nickel and no

\r?\n> carbon. They are

\r?\n> typically magnetic and this is the big difference from their austentic

\r?\n> cousins, which are non-magnetic but more corrosion resistant. So

\r?\n> if you have

\r?\n> slightly stained stainless spokes they will be ferritic. From a

\r?\n> random check

\r?\n> in the garage Dunlop stainless rims are austenitic but I have

\r?\n> 'stainless'spokes that are both magnetic and non magnetic.

\r?\n> For the benefit of the minority UK members and those in the

\r?\n> parts of the US

\r?\n> and Canada subject to ice and hence salt on roads, austenitic

\r?\n> (non-magnetic)

\r?\n> stainless steels do not like a salt environment and can crack

\r?\n> through a

\r?\n> stress corrosion mechanism, that I won't elaborate on here, just

\r?\n> to say it

\r?\n> has caused many big bangs in process plants, like refineries.

\r?\n>

\r?\n> Nigel Land

\r?\n>

\r?\n> East Coast of England (about half way up)

\r?\n>

\r?\n>

\r?\n> Date: Tue, 30 May 2006 07:31:23 -0400

\r?\n> From: cpotz@aol.com

\r?\n> To: classicrendezvous@bikelist.org

\r?\n> Subject: [CR]Re: Classicrendezvous Digest, Vol 41, Issue 112

\r?\n> Message-ID: <8C851F3B6D8773F-534-1CD9@FWM-D20.sysops.aol.com>

\r?\n> In-Reply-To:

\r?\n> References:

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\r?\n>

\r?\n> not all 'stainless' is, my 1947? Raleigh Lenton Clubman retains

\r?\n> it's origina

\r?\n> l front wheel which has 'stainless' spokes only some have

\r?\n> 'rusted' a bit,the

\r?\n> y are all the same and have an R on each head ,and are all very

\r?\n> slightly mag

\r?\n> netic ,but ARE stainless..steve chambers chesterfield england