Is there any way to know if a part is made of powder metal?

Other than performing tests using expensive lab equipment, are there any dead giveaways that a part is made of powder metal?

 

Is there two broken teeth? I assume it’s steel since it’s a gear. So if it’s PM the broken areas will look like a broken cast aluminum part.

 

Also, I see the gear module and tooth count on this side. Is there any other writing on the other side of the gear. It might have the material written on it.

 

No writing on the other side. It's sold as a "steel" gear.

 

Looks like cast aluminum to me but it's WAY too heavy to be aluminum.

 

I'm 98% sure that is powdered metal. A quality hobbed gear will have a very small area of brittle fracture on the edges and the bulk of it will be a more ductile failure. That uniformly looks like potting soil.

 

Yup. Looks like PM to me.

 

Either sintered metal or die cast. Either way, not nearly as strong, but much cheaper to produce.

Edit: upon closer inspection, it has none of the telltale marks of a die cast part. So, sintered metal.

 

Look for parting lines, ejector pin markings, flashing, draft angles on the vertical surfaces.

From the pics that is a cast/injected/PM part, the holes and edge of the teeth show flashing that indicates a cast or MIM part.

 

I do want to add that that powdered metal gears are pressed in a mold and then sintered. There can be "flashing" marks from poor die clearances, complex geometry, or general laziness. Specifically the cupped looking flashing on the teeth is what I would expect from a die set that nests into one another, which is the easiest way to make gear shapes.

Not really sure why the surface finish is so abysmal on certain parts. That's not inherent to any particular process except for maybe sand casting, which this is not. Unless they put that texture in the mold to make it look like a cast and hobbed gear that doesn't suck as bad.