Are they trash?

[blades&grace]

Here's a bad day for you!
I had a controller malfunction and over heated some ATS-34 blades. I caught them at about 2175f or maybe even higher....one was too far twisted to save. Needless to say ....I'm in the market for a new controller. The other 2 had the foil melted to them but I was able to regrind them and clean them up. Don't ask me why.... but I could let it go I had too much time in file work. They RC'ed at 47....which may be due to the fact that I failed to pull them out fast enough for a good quench. The real question is….. Can these blades be re-heat treated? Or are they trash.

Thanks for your time.

Brent Cramer

 

[Nathan the Machinist]

So long as that didn't get white hot and start sparking they're okay. Grain coarsening is reversible with normalization. I don't know the procedure for ats34, but it will probably be something like a long soak at something like 1400, another soak at some higher temperature, and a long cool down.

A metallurgist can tell you exactly what to do. But, yeah, I think they'll be fine so long as they were protected from the atmosphere and you address the grain size.

Which foil were you using that held up at 2100? 309?

Had it been a powered metal, S30V, you'd probably be in trouble

 

[blades&grace]

Thanks Nathan,

That's what I thought but with the way the foil kinda melted right into the blades I was afraid that some how the steel would be compromised.
As for the foil the controller was flickering 2175f it could have been cooler but I know it was hot!!!! Maybe not white hot (no sparks) but close.

This roll of foil was a gift and didn't even think to ask what it was. I've used it on many blades before with good results. This time something bad happened to this cheap Chinese controller I used to cut cost on the oven I built. Never again!
Thank you for responding.
Brent Cramer

 

[Gene Martin]

Try annealing them. There are 2 recipes. The first:
heat to 1650F, hold six hours, cool slowly (25F/hour max) to 1200F, the air cool.
Method 2:
Heat tp 1600F, hold 2 hours, cool to 1300F, hold 4 hours, thewn air cool.

I've used recipe 2 for annealing blades that warped badly to get a second shot at them. Works just fine.

Gene