Alcoa Fastening Systems - DS( )( )7900

[ehrenfried]

Hi,

I'm looking for the Ultimate Tensile Strenght of the bolts for series DS( )( )7900 Alcoa fastening system. (The bolts are made of AISI 302 CRES and the strength properties can vary from 640 to 1200 MPa depending on the manufactoring process.
Does anyone know more about these bolts?

Regards
E. Peter

 

[WKTaylor]

ehrenfried... Go to:

http://www.alcoa.com/fastening_systems/aerospace/catalog/pdf/S-2006AC.pdf

Then call the Alcoa Tech Reps for help. They may the Qual- Spec requirements that specify what You need.

These are appear non-structural... so don't be suprised with the answer You get.

Regards, Wil Taylor

 

[ehrenfried]

Hi Wil,
thank You for Your answer so far.
I,ve already contacted the Alcoa support in parallel to this thread. They forwarded my question to the german representative. He could tell me that the thread is cold rolled and the thread recess is grinded. But a concrte value for the ultimate tensile strength is still missing.
Regards
Ehrenfried Peter

 

[WKTaylor]

ehrenfried...

Then You have these options.

Select other captive screw design(s) that HAS(HAVE) published allowables.

Calculate the worst case allowables... and decrese that calculation by X/1.15 ... or some other rational "factor".

Buy a bunch and generate Your own allowables by testing [specific size(s) to meet You're needs...or various sizes for use in-general]



Regards, Wil Taylor

 

[wallyd999]

alcoa has their mind buried. since they have bought all of the old manufacturers and consolidated everyone, they have lost a lot of talent that would be able to help you. you will either have to go up the food chain to get an answer or try to find an alternate to alcoa.

i hope there will be an alternate sooner than later. try Shur-Loc in California, they are trying to get competitive with some fastening systems.

 

[Kaynarguy]

What you have to remember on these types of fasteners is that the sleeve section will start to collapse before any ultimate load is seen on the threaded bolt. Also as mentioned earlier these are not designed as structural fasteners which is why no tensile data is given.

Regards,

Dave Beckett
Alcoa Fastening Systems

http://www.alcoafasteners.com

 

[WKTaylor]

Kaynarguy...

EVERY fastener has the expectation of load-capacity, regardless whether it is designated as a structural or non-structural fastener.

NO tension and/or shear-allowable numbers leaves the user in-the-cold... even for simple applications with light loads [ee-el box cover, decorative panel fastening, etc]... performance minimums are required.

Regards, Wil Taylor

 

[Kaynarguy]

302 CRES (AMS5636) has a min tensile strength of 100
KSI.

Dave Beckett
Alcoa Fastening Systems

http://www.alcoafasteners.com

 

[ehrenfried]

Hi,

I agree with wktaylor. The fasteners are used to mount electronic boxes to the chassis of an airplane. I was asked to perform a crash safety analysis for the qualification of this product and this includes a bolt verification.
Finally the the ALCOA agency in Germany could help me with
following information:
"screw component of DSCU7900 captive screw is manufactured from UNS S30200 corrosion resistant wire having a minimum tensile and yield strength of 100 and 60 ksi, respectively.
The part is manufactored by cold-forming the head, grinding thread relief and the threads are cold-rolled during the assembly process ..."

Regards
Ehrenfried Peter
EADS Deutschland GmbH