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Dilivar Specifications

Dilivar Specifications

Dilivar Specifications

(OP)
G'Day,
Would anyone have the density, coefficient of expansion and tensile strength of Dilivar? It is used in the Porsche 911 engines for the through studs. I believe the coefficient of expansion is about half way between aluminum and steel. I had no hits on this question from the Materials forum.
Thanks.

RE: Dilivar Specifications

magnograil,

I've never seen any data for Dilivar. I'm sure it's a proprietary alloy.

However, if you want a good fastener material with a CTE fairly close to aluminum, take a look at A286 cres. It's a common fastener material, has good tensile strength (146 ksi uts), responds to heat treatment, is corrosion resistant, has a CTE between aluminum and steel (9.4 x 10-6 in/in-degF), and is readily available.

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=Q660AC

Regards,
Terry

RE: Dilivar Specifications

Must be a trade name. I just searched and couldn't find anything either. Take a look at the link below, and page down to the section on high and low thermal expansion alloys. It is probably similar.

http://www.key-to-steel.com/Articles/Art9.htm

RE: Dilivar Specifications

(OP)
Thanks to both. I checked the name in a Porsche performance handbook and it is Dilavar, sorry. I know one problem is fracturing from corrosion. Even newly installed parts will sometimes break within a few hours of being torqued. Probably due to hydrogen embrittlement. The latest parts have a gold colored coating or an epoxy finish. My understanding from hard chrome plating is the hydrogen can be removed by heating to about 400F for four hours. I hope the same applies to Dilavar.
I will check out the A236 alloy, thanks. My application is the Norton rotary that currently uses 1/4" through studs and for some inexplicable reason they put 1/4"-28 Heli-coils to retain the studs in aluminum. If there is enough material around the holes I can possibly change to 7mm Time-serts.

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