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RE: Grade 8 bolt properties

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This is a problem that goes back to the 1980's.  The following is contained in the NASA 1228 by Barrett that was published in 1990. 
 
Counterfeit Fasteners

In the past two years a great deal of concern and publicity

about counterfeit fasteners has surfaced. The counterfeit case

with the most documentation is the deliberate marking of

grade 8.2 boron bolts as grade 8 bolts.

Grade 8.2 bolts are a low-carbon (0.22 percent C) boron

alloy steel that can be heat treated to the same roomtemperature

hardness as grade 8 medium-carbon (0.37 percent

C) steel. However, the room- and elevated-temperature

strengths of the grade 8.2 bolts drop drastically if they are

exposed to temperatures above 500 OF. Grade 8 bolts can be

used to 800 OF with little loss of room-temperature strength.

Other fasteners marked as MS and NAS but not up to the

respective MS or NAS specification have shown up; however,

documentation is not readily available. Since these fasteners

are imported and have no manufacturer's identification mark

on them, it is not possible to trace them back to the guilty

manufacturer. U. S . Customs inspections have not been

effective in intercepting counterfeit fasteners.

Another problem with fasteners has been the substitution

of zinc coating for cadmium coating. If a dye is used with the

zinc, the only way to detect the difference in coatings is by

chemical testing.

Federal legislation to establish control of fastener materials

from the material producer to the consumer is being

formulated.


Regards, Harold Sprague


 
> Date: Thu, 26 Nov 2009 07:39:34 -0500
> From: design(--nospam--at)hodgsoneng.ca
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Grade 8 bolt properties
>
> I deal with ferro-manurium almost every day and some of it involves
> engineering.
> Gary
>
> Christopher Wright wrote:
> >
> > On Nov 24, 2009, at 6:58 AM, Gary L. Hodgson and Assoc. wrote:
> >
> >> I have one customer who keeps wanting to use the nice shiny SAE grade
> >> 8 bolts because they look better than those black A325 or A490 bolts.
> > To make things worse, the Counterfeit Bolt Affair of the 1990's hasn't
> > gone away. If anything it's gotten worse.
> > <http://www.nv.doe.gov/library/publications/sitelines/sl100.pdf> The
> > original problem was with so-called grade 8 bolts that were actually
> > grade 8.2 (or something like it) that were understrength or wouldn't
> > hold a pre-load. So when you go through all your spec options keep in
> > mind that you could be getting ferro-manurium fasteners if you don't
> > shop with care.
> >
> > Christopher Wright P.E. |"They couldn't hit an elephant at
> > chrisw(--nospam--at)skypoint.com | this distance" (last words of Gen.
> > .......................................| John Sedgwick, Spotsylvania
> > 1864)
> > http://www.skypoint.com/members/chrisw/
> >
> >
> >
> >
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