HT'ing 400c-How to do it

S

sixth_sense

Joined
Dec 29, 2005
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I'm sure others have asked this question but I can not find a relavent thread.... I ust got my Sugar Creek Oven and looking to HT my first blades. They are 440c. I'm wondering if anyone would be willing to share some advice on best methods. My understanding is that I should bring to 1880 and hold for 30 min. then quench in oil. Then I put it back in at 375 to temper.

Sound about right?

Thanks in advance.
 
You are on the right track. I presume you know about foil wrap or some method of excluding oxygen. 30 minute soak is OK if your temp is good and foil pack is well sealed, but half that is probably plenty for 440C blades. Consider cryo - it does make a difference.

Tempering temperature depends on the hardness you want. 375 - for two hours - twice - should come out near RHC57 without cryo.

See if you can find a Rockwell tester to check your initial results at least till you have some confidence in your process.

Rob!
 
With a foil pack, are you guys oil quenching with the blade inside the foil? Or are you cutting the pack and dumping the blade into the oil? I guess I'm more familiar with foil wrapping and air quenching or plate quenching.

--nathan
 
OIL?? Yuk! :barf:

Plate quench the 440C :thumbup: - yes, still in the foil.

Nathan, if you are talking about steels that need oil quench, I use turco instead of foil - but I don't do much oil quench work anymore.

Rob!
 
With 440c i have been doing like so:

foil wrap blades, double crimp outer edges.
set oven for 1875..,i place blades in when oven reaches 1650.
leave in until oven reaches 1875 with your desired hold time.mine
is 22 minutes!remove and plate quench while blades are still in foil.

I strongly reccomend you invest in quench plates.you can find them
cheap on e-bay.i picked mine up for $25. they're 12" x 11" x 1 1/2".
i used standard air quench at first but theres alot less fooling with
the plates,and less time fooling on the arbor press :)

you can do a snap temper aswell.pick up a cheap toaster oven with couple good thermometers, when blades are cool enough to handle or (125f)throw them in the pre-heated toaster oven for an hour at low temp.once oven cool's,i do two tempering cycles between 375-425,depending on your target hardness.for two hours each time, my toaster oven holds temp's very accurate (surprisingly).i can temper in it if i like,i just feel better using the
oven.
 
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