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Bolt Specification

02/27/2010 5:39 AM

i have found the bolt head been marked with PFS 8.8 (india )flanged bolts

what does it mean

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Anonymous Poster
#1

Re: Bolt Specification

02/27/2010 8:19 AM

PFS is most likely the manufacturer's trade mark

8.8 is the property class.

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Guru

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#2

Re: Bolt Specification

02/27/2010 11:24 AM

It relates to the UTS (ultimate tensile stress) of the steel. UTS = 8000 kgf/cm2 = 785 N/mm2 = 785 MPa. I'm not sure of the significance of the .8, perhaps it's just a convention. Grade 8 is recommended nut with grade 8.8 bolt.

Cheers.......Codey

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Anonymous Poster
#3
In reply to #2

Re: Bolt Specification

02/27/2010 12:18 PM

8.8 bolts; the first 8 signifies an ultimate tensile of 800 N/mm2; the second 8 signifies that the yield strength is 80% of this value = 640 N/mm2.

Another example; 10.9 bolts - a 1000 N/mm2 tensile; 900 N/mm2 yield.

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Power-User

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#4

Re: Bolt Specification

02/27/2010 10:43 PM

What does it mean? It means one or more of the following:

a) that the bolts were made by a manufacturer who has registered PFS as his ID and the bolts conform to the 8.8 class enumerated;

b) that the bolts were made by a manufacturer who has registered PFS as his ID and the bolts were hoped to conform to 8.8 but were rejected, tipped in the dumpster and later "rescued" by an enterprising re-seller;

c) that the manufacturer, not being PFS, thought he had more chance of selling them if he masqueraded as PFS;

d) that the manufacturer, possibly not being PFS, thought he could gain a higher price if you thought they were class 8.8 product.

Mark B
Relativity PL

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Anonymous Poster
#5
In reply to #4

Re: Bolt Specification

02/28/2010 12:37 AM

(b) is a bit unlikely - the reputed manufacturers deface the markings before putting into dust-bin. (PFS is a bit reputed)

However there is a corollary - a lot of users of bolts like us do not do this when the bolts are damaged/ removed from equipment and dumped into reject bin, we definitely don't and these go out through our scrap re-sale route to GOK where.

Why only bolts - even critical items like bearings, gears follow same route - supposed to be re-melted by some foundry.

Large organisations like us, of course protect ourselves (by avoiding dealers) and transacting through the company directly - so our bolts are from directly PFS, Unbrako, TVS etc but again smaller or even medium playesrs are at the mercy of the honesty of the dealer. (eg the fittings without marking a few days back thread)

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Guru

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#6

Re: Bolt Specification

02/28/2010 4:26 AM

Hud,

According to DIN EN 20 898, ( by this numerical ID metric is indicated) the properties of a fastener are identified by two numbers separated by a decimal point. The first number equals 1/100th of the minimum tensile strength: the second is a number that is 10 times the ratio of the yield point in relation to the tensile strength.

Multiplying the two numbers gives 1/10of the minimum yield point.

An example: 8.8----Re = Rpo.2 = 640MPa. Re=yield point. Rpo.2=0.2% yield strength. all Newtons/mm2.

the property class of a standard nut is identified by one number.

This corresponds to 1/100th of the minimum tensile strength of a bolt of the same property class.

Bolts and nuts of the same property class should always be paired. e.g. 8 nut with 8.8 bolt.

Hope this helps,

Stu.

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Commentator

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#7

Re: Bolt Specification

02/28/2010 2:03 PM

Hello hudsthomas,

The Flanged Bolt Marked (PFS) Pierceform Stud, is considered a special production stud designed for fast production assembly. It is commonly used in automotive body assembly in conjunction with special nut fasteners.

The 8.8 is the stencil strength of the metal used to manufacture the bolt. If it has an underline under the 8.8 means it is made with boron steel properties which is slightly harder then the 8.8 Grade.

See link below for more supplier details;

Best regards, Tim

http://www.fabristeel.com/GeneralInfo/Brochures/PierceFasteningTech.pdf

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Active Contributor
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#8

Re: Bolt Specification

02/28/2010 11:15 PM

you all for the information,,

hudson thomas

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Anonymous Poster (3); Codemaster (1); hudsthomas (1); Relativity PL (1); Stueywright (1); Tim Hawley Master Mech (1)

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