Interesting point, Jan. As far as I have ever heard, there are two chrome
plating processes. Decorative and Hard. Both are electroplating processes,
both require very clean base metal. The Hard plating is done at high
temperatures for extended periods of time, and does not include nickle base.
It is done to build up a hard, durable surface. I would imagine this process
would be used in rifle barrels, although I do not know.
Speaking of base metal, almost any high quality finish, including paint and
powder, will include a pass through a phosphoric acid bath. This is a mild
form of pickling, as it is done to clean the part and etch the surface to
enhance adhesion. Would this count on the hydrogen embrittlement issue?
Perhaps if a person wants chrome wires, the best thing would be to avoid
ones made with anything other than low carbon steel. Sounds as though this
is one of those interesting situations where the answer lies with using less
than the "very best", so no one will brag about it!
Bill
----- Original Message -----
From: "Jan Eyerman" <jan.eyerman@usa.net>
To: "DrMayf" <drmayf@teknett.com>; "Bill Blue" <dablue@worldnet.att.net>;
"Armand Ritchie" <ritchie@mcn.org>; <alpines@autox.team.net>
Sent: Monday, December 24, 2001 4:33 PM
Subject: Re: [Re: Help me decide!!]
I believe that we are talking about critical components in aircraft, space
vehicles and racing cars. I don't think that chrome plating would have any
measureable effects on door handles, trim pieces, air cleaners or manifolds.
I don't think I would chrome plate a front suspension arm though.
However, it is interesting that M16 rifles have chrome plated bores and
chambers. Since these are subjected to 50,000 PSI every time they are
fired,
maybe the gun makers use some different method of plating them.
Jan Eyerman
CPT USAR Ordnance Corps, retired
"DrMayf" <drmayf@teknett.com> wrote:
Bill, all. I used the message to add some thoughts of my own, not picking on
anyone...just an easy place to reply...
This is an interesting thread. I surfed a bit using Google and found this:
"Hydrogen Embrittlement
High strength steel, such as quenched and tempered steels or precipitation
hardened steels are particularly susceptible to hydrogen embrittlement.
Hydrogen can be introduced into the material in service or during materials
processing.
Hydrogen Embrittlement Failures
Tensile stresses, susceptible material, and the presence of hydrogen are
necessary to cause hydrogen embrittlement. Residual stresses or externally
applied loads resulting in stresses significantly below yield stresses can
cause cracking. Thus, catastrophic failure can occur without significant
deformation or obvious deterioration of the component.
Very small amounts of hydrogen can cause hydrogen embrittlement in high
strength steels. Common causes of hydrogen embrittlement are pickling,
electroplating and welding, however hydrogen embrittlement is not limited to
these processes.
Hydrogen embrittlement is an insidious type of failure as it can occur
without an externally applied load or at loads significantly below yield
stress. While high strength steels are the most common case of hydrogen
embrittlement all materials are susceptible. "
>From the above, it would appear that electroplating does indeed cause
hydrogen embrittlement. Anothe paper I scanned said that the hydrogen comes
from the cleaning process used in plating: that it comes from the acid
solution used to clean the parts. Then the parts are plated over entrapping
the hydrogen. Additionally failures are accelerated when the materials are
put into tensile stress (spokes). I remember as an engineer using high
strength materials that we had to specify that parts be baked for quite some
long periods to remove hydrogen to prevent stress failures.
hope this helps to clear the air...
mayf, the red necked ignorant desert rat and hooligan in Pahrump
----- Original Message -----
From: "Bill Blue" <dablue@worldnet.att.net>
To: "Armand Ritchie" <ritchie@mcn.org>; <alpines@autox.team.net>
Sent: Monday, December 24, 2001 6:39 AM
Subject: Re: Help me decide!!
> I don't think there is any way that chrome plating causes brittleness. My
> job takes me into pretty close contact with electroplaters, and
> enbrittlement is something I have never heard them discuss.
Electroplating
> uses a low voltage DC current which should not alter the properties of the
> parent material. I would guess the broken spoke was due to the use of an
> improper steel alloy or perhaps a slag inclusion in the steel.
>
> There is another process that is used to dip bodies. Once more, this is
> someting I have heard about as part of work, so I don't know a lot about
it.
> I do know there is a fellow in Evansville, Indiana that dips bodies in a
> cyanide solution. I have not seen the results, but my contact in
Evansville
> says it does a beautiful job, much like the process Ian and Jan use.
> Bill
> ----- Original Message -----
> From: "Armand Ritchie" <ritchie@mcn.org>
> To: <alpines@autox.team.net>
> Sent: Sunday, December 23, 2001 4:03 PM
> Subject: Re: Help me decide!!
>
>
> > Paul,
> > I have had both chrome and painted wire wheels in the past and I can
tell
> > you my opinion. The chromes look great but are a pain to keep clean,
they
> > seem to attract dirt like a magnet. The painted ones always seem to
look
> > good, even when there a little dirty you don't notice it as much.
> > I also had a problem years ago with the chrome wires on my Triumph Stag.
> > The spokes them selves were very brittle and I found one of them broken
> > (snapped in the middle like a pretzel) after a trip through the car
wash.
> > I always thought that the brittleness was from the chroming process but
> I'm
> > not sure on that.
> >
> > regards
> > Armand
> >
> >
> >
> >
> >
> > >List,
> > >I just received a nice Christmas award gift ($$$$) and would like to
put
> > >it into my Series 3 estoration before he wife gets wind of it. I need
> you
> > >guys to help me decide on something.
> > >
> > >I am going to buy new wire wheels from British Wire Wheel with this
cash.
> > >The question is should I buy regular wire and paint them or go with all
> > >chrome?
> > >I have been researching powder colors for months and cannot get an
exact
> > >match. I did however come very close to the original sample from Ian
and
> > >Company. (just a shade darker) Custom matching the powder is going to
be
> > >too expensive so that's not an option. Also, regular paint is not an
> > >option as I'm addicted to powders durability and connot get myself to
use
> > >liquid paint. Unless you can talk me into it.
> > >I attended the British Conclave in Denver last summer and looked at
> > >hundreds of british cars with wire wheels and chrome knock-offs. I
> looked
> > >at many with chrome wires and many more with paint. I must admit, the
> > >chrome looked better to me. Although I was leaning to keep the
original
> > >period look, I walked away confused and wanting Chrome!
> > >BTW, my 3 eared knock-off's are already back from the chrome shop and
> look
> > >FANTASTIC!! Better than factory!!
> > >
> > >Help me!
> > >Paul
> > >Colorado
> > >Series 3 GT (waiting on body paint and still throwing "stupid" money at
> > >it) :)
> >
> > ritchie@mcn.org
> > Armand Ritchie
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