Question on 52100

#1
Kevin, this is for you as you asked. You posted that 52100 needs to be spherodized, due to it's chromium content which it will do better than 1095. I guess what through me is it wasn't clear what would be better than 1095.

Doug
 
#2
Chromium has a much higher affinity with carbon than iron does, this has an effect on diffusive processes, thus you get deeper hardening due to the suppression of pearlite formation. 1095 loves to make pearlite with proeutectoid carbide sheets, it really needs to be coaxed to ball that carbide up in a ferritic matrix instead. But chromium is greedy for carbon and will readily latch onto any that is free. Slow cool 1095 from austenitic and you will get coarse pearlite with networked cementite. Slow cool 52100 and you will get finer pearlite loaded with chromium enriched carbides. These carbides are like little seeds for the divorced eutectoid transformation, encouraging spheroids, in an isothermal anneal, rather than lamellar Fe/Fe3c. The danger is that it will prefer the grain boundaries if the austenite cools too slowly. This effect is not as great as with steels with higher chromium contents which will exhibit all out chromium carbide behaviors, like big blocky carbides and even better spheroidization.

Ignoring all the technobabble just do this- take a piece of 1095 and a piece of 52100, normalize them both and then reheat both to 1300°F to spheroidize. Then see which one will drill easier. I just experienced this drilling both 1095 and 52100 samples to hang from a wire, totally trashed a couple of bits on the 1095 while the 52100 was tamed rather quickly and cost me no extra bits. Now let’s be clear, if you do not spheroidize the 52100 will make you wish you had good old 1095 to drill as it will be akin to drilling a diamond, but spheroidized it is a different situation.
 
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