HT question

[Andre V]

When heat treating is it advisable to put the blades in an cooled furnace and bring them up to Hardening temperature, or is it better to preheat oven and then put blades in.

Specifically ATS 34, 154CM and D2.

Thanks in advance.

 

[mete]

Preheat the furnace first.With those steel you will be putting the blades in sealed stainless steel foil. Plate quenching is also recommended.

 

[Rob!]

I put them in from cold. If the envelope is sealed tight, I don't get any problems. That also lets the paper burn off any oxygen in the foil pack long before it gets anywhere near a decarb risk. Lastly 154CM is suppose to equalize at 1400 degrees before increasing to austenizing temperature.

Mete has way more experince and knowledge than I do but this works for me. Oh yes, I agree - plate quenching is the ONLY way to go. :thumbup:

Rob!

 

[Andre V]

Thanks guys.

 

[mete]

Rob! , It isn't critical but I prefer putting it in hot . The idea of equalizing at 1400F is really for large cross sections so that the surface and center get to the same temperature at the same time .It's not significant for blades.I hope you're using a furnace that will get to the 1900-2000 F easily that means a furnace capable of about 2200 F max.

 

[Rob!]

You bet! Evenheat 22.5 inch -3600 watts on 220. :thumbup: It's designed for 2200 degrees and will go higher if necessary - but I have no steel that needs that level.

I like to just take the foil wrapped blades out -put them in the slotted fire brick - push "program one" and go. Then I set alarms on the kiln and all over the house to get me back out there about 15 minutes before the soak is done.

I used to use an old amoco 115V kiln. It had no computer control so you had to stand there and watch the temperature, turning up a little - down a little. That one took about 3 - 4 hours to get to 2000 degrees, so yes, I did preheat it. For the last couple years, I just used it for snap tempers and last week, I sold it. I kind of miss it. Part of my roots I guess.

Rob!

 

[Andre V]

My furnace goes up to 1200 deg C which is 2192 F. I will only be treating blades really. My max thickness is 5mm.

My main concern is that i didn't want the hardening procedure to start happening before i reached my soaking temp. To get from about 800 deg C (1500F approx) to 1025 (approx 1880) will take about 8-10 mins.

Is it better to preheat the oven to about 1400 then insert blade and bring up to soaking temp? And how long must i keep it at that temp?

Is it also okay to just drop it in a hot furnace at soaking temp?

 

[CUTS LIKE A KRIS]

" used to use an old amoco 115V kiln. It had no computer control so you had to stand there and watch the temperature, turning up a little - down a little. That one took about 3 - 4 hours to get to 2000 degrees, so yes, I did preheat it. For the last couple years, I just used it for snap tempers and last week, I sold it. I kind of miss it. Part of my roots I guess.

Rob!
"

Don't worry Rob- it went to a good home
And I'm sure you could get some visitation rights if you are nice enough- the new owner seems to be a good guy!

 

[Rob!]

Awww!!!! Thanks Kris. I just might take you up on that if Marilyn ever lets me out of the dungeon.