Is This A Metal Turbine?

[DrexNX]

so I bought a set of japan-rebuilt stockers - the usual "12 point nut=ceramic, 6 point nut=metal" wheel rule may not apply in this case - and I can't seem to google image a good macro shot of the ceramic wheels to really identify, so what do you think? there looks like some slight casting flash that points to metal, but then again I don't know how they made the ceramic wheels either. my first instinct was check the electrical resistance, even inconel will have a much lower resistance than any kind of ceramic, but I can't get a resistance reading on my multimeter.

also the wastegate port is cracked - not to the turbine wheel, but it definitely goes through the whole housing. I'm used to seeing some cracking on IHI subaru turbos but I didn't think garretts had the same issue

[GTSBoy]

Of course it's not ceramic. Any turbo that has an aftermarket tag on it will not be ceramic. And they just don't look like the millions of photos of ceramic turbines anyway.

Here's a tip to work out what you have. Hit them with a small hammer. If they break, they were ceramic. Then you get them rebuilt properly.

[DRF72]

Also early Garrett exhaust housings have the same issue as the IHI housings and crack around the wastegate exhaust port. Another thing to keep in mind is that these castings are not always cast the same way and other companies that copy Garrett and IHI exhaust housings do not always use the same metals in the casting nor the right sand for the casting and this leads to a weaker casted product.