S90V folding like a noodle

M

muledogg

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Sep 4, 2024
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Hello, all on the forms. Not really a forms guy so this is my first thread post on the WWW. Thank you for having me and please go easy on me.

I have been doing traditional tool steels with great results and really loving the ride. Just had my first experiment with super steels, as the title reads, S90V. This has led to my first failure. My goal was Austenitize at 2100F but midway ramp a connection was getting a little warm. This was causing a voltage drop and extending the ramp time. Time running out of time I bite the bullet, fixed the issue, and allowed to ramp to 2050F. That is where it got interesting. When the oven was open the steel was slumped looking akin to melted glass...picking up by the remaining 309 foil the whole thing flexed like a wet noodle. While the packet was still viable to lift the steel it was really stuck...scratching it or grinding does not reveal an edge to even pick at.

Couple thoughts. My controller/thermocouple combo max is 2200. Maybe it's maxed and reading incorrectly thus forge welding the packet? Or is my soak time doing something? Or is this why plate quenching is popular - it supports the noodle? Does anyone have some experience that could narrow down the variables?
 
Was your blade laying flat or edge up? I’ve had foil weld before and it’s a nightmare, I dust my blades really well with talcum powder before sealing them in the foil and never had it happen again.
 
Edge up. In the past I have not issues but will have to give the talcum powder a try.

I will note that part of the blade was unground and still had its mill scale. Welded solid there, too!

Thanks for the tip!
 
I have not had an issue with 309 up to 2150°F but I have had bad foil weld issues using 321 at 2000°F

Plates are nice for quickly cooling blanks and keeping the blank flat.
 
ive run 321 foil as high as 2050f with no welding foil to the blade but one time i ran it on a s125v blade at 2100f and for sure welded that foil right to the blade. i have never needed to add anything to the pouch to keep from having the welding issue
 
Don't put the blade in until it gets to temp. Put the blade/envelope in at this time and start the austenitizing cycle timing when the temp rebounds to setpoint. You don't need soaks for blade-thick cross sections.

There are differences in quality in envelope sheet beyond just the alloy. They are simply not all created equal and some have more of a tendency to stick than others. The talc helps even the playing field.

PS If you can afford it, an external temp meter, a long Inconel type K probe, and a couple 1/4 holes in your furnace will teach you a lot about how the chamber heats and also a double check on your control system. Spend the extra money on something prime like Fluke or Omega.
 
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Obviously, your controller and/or TC did not work and the temperature went to as high as the coils would take it. That issue needs to be fixed and tested before relying on the oven for HT.
I would suggest replacing the TC.
I also agree with Fitzo that you should put in a secondary TC to read the temp as a backup reference. A low-cost temperature reader or cheap PID and a good quality TC can save a lot of headaches and heartaches.
 
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The double redundancy on the controller is a great idea. Thanks for giving me some direction.
 
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