Re: Sintered Metal

[bearbvd@domain.elided (Greg Hermann)]

>Somewhere in my house I have a sintered-metal nutcracker from Alfa, dating
>from the early 1980s. The unit is made up of two identical castings which
>interlock to make the nutcracker. The handles are quite thin, and I thought
>they might break under heavy presssure. I couldn't squeeze them hard enough
>to damage them (and I was younger then, too). I'm not a metalurgist, but I
>suspect that sintered metals are quite strong. A number of manufacturers are
>using fractured big ends: Hyundai does this on their new V6 engine, and the
>rods are sintered metal. My impression is that the sintered metal fractures
>more precisely than traditional cast or forged rods (having to do with a
>more uniform grain of the metal). While this fact may not be so overwhelming
>as to compel readers to rush to their local Hyundai dealer, it does suggest
>that sintered metal has excellent strength. As far as abrasion, relative to
>an impeller, that may be another story.

My question was never about strength, although I may not have made that
point clear, Pat. It was about ductility, impact strength, and whether
sintered metal parts even posess a well defined endurance limit in a full
alternating stress fatigue situation. All of these factors are about
equally as important as ultimate strength in a part like a connecting rod.

The fact that the caps CAN be broken without utterly destroying the
usefulness of the about to be part through distortion speaks volumes about
the ductility, and, most likely, the impact strength of the subject parts!!

Regards, Greg

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