Power outage in the middle of heat treat..

[Wolf Creek Forge]

Was working on two batches of blades last night..Got one batch of CPM154 done and in the sub zero quench and got about halfway thru a batch of D2 when the power went out Oh, well..My question is, today I did a two hour stress relief at 1200°..Im guessing that should be good? Now go ahead and heat treat as normal? Thanks

 

[Nathan the Machinist]

It depends on how high you austenitize your blades and what flavor of D2 you're working with. One of the quirks of D2 and other complex steels such as HSS is that a second heat can cause extreme grain growth. But if you use the typical heat of 1850 you are most likely just fine.

D2 has a long soak, and if you were only half way through it the carbides that pin the grain that are dissolved before saturation on a second heat are probably still large enough to still do their job. In fact, you may even get some grain refinement (assuming you've been using normal heats) because this is fundamentally not that different from a 1700F prequench that reduces grain size on spheroidized D2 with normal amounts of vanadium in it. I would reduce my soak time on the second heat to 20 min and drop the temp to 1825 to compensate for the fact that you already have some carbon in solution. And then I'd test one of the blades to confirm the results, paying particular attention to the tip, which is where a problem would mostly likely present itself.

 

[Wolf Creek Forge]

Thanks, yes I use the typical 1850° with a 45 min soak..What about CPMD2?

 

[Stacy E. Apelt - Bladesmith]

It should be the same.