Heat treat question using new oven

killthelights

killthelights

Joined
Jan 6, 2016
Messages
244
Hypothetically speaking, some idiot put a couple of knives(1095) in his oven and set the controls to get to 1475 asap. Now that same idiot didn't hear the alarm and didn't quench until the temp in the oven had dropped to around 1200F. TWICE! Two times this happened. The question is are these knives salvageable? Just curious in case it happens to someone I know. Thanks.
 
I don t see anything bad .Put them back in oven and HT them again .This time do it right :D Maybe you will have more decarb, on surface but that is not big problem . In any case, wait for someone much smarter than us to come with answer on your question :)
 
Natlek said:
I don t see anything bad .Put them back in oven and HT them again .This time do it right :D Maybe you will have more decarb, on surface but that is not big problem . In any case, wait for someone much smarter than us to come with answer on your question :)
Click to expand...
Right on. Thanks!
 
killthelights said:
didn't hear the alarm and didn't quench until the temp in the oven had dropped to around 1200F.
Click to expand...

Given the above info i'm surprised to hear this conclusion-
Stacy E. Apelt - Bladesmith said:
No issues, all you did is refine the grain a little and removed all the stress ...
Click to expand...

Would not it matter for how long the kiln held those at crit.?(1475 F in this case it seems).

What was the soak-time,if set?Or,if kiln was set for a correct amount of soaking,and then automatically lowered the temp to 1200 or whatever below crit.,that no excessive grain-growth would result?
(sorry if i'm being dense and there's enough info above to've already answered these questions).

After reading this question last night my thought was that the forgings would have to be re-normalised...
 
Over austinizing will be an issue when the temperature is above 1650-1700F. Time is more significant at that temperature. Also, it is time above Ac/Ar that counts. Below the critical point, the steel returned to pearlite and slow cooled for what I would guess was an hour at most ( to drop to 1200F).

A 1475F normal soak time, then oven cooling to 1200F will not grow grain or damage the steel.

A new soak at 1475F followed by a quench should yield a fine grain and full hardness.
 
Thank you for this expanded answer.

I'm of a solid-fuel kind of persuasion,and have no way to measure T;ironically it makes the theory even more important to understand.
 
killthelights said:
Hypothetically speaking, some idiot put a couple of knives(1095) in his oven and set the controls to get to 1475 asap. Now that same idiot didn't hear the alarm and didn't quench until the temp in the oven had dropped to around 1200F. TWICE! Two times this happened. The question is are these knives salvageable? Just curious in case it happens to someone I know. Thanks.
Click to expand...
You should set the temp on your oven and leave it for up to an hour to let it fully heat and equalise then put in your blades.radiant heat from coils can be way too hot when heating up for blades
 
Stacy E. Apelt - Bladesmith said:
Over austinizing will be an issue when the temperature is above 1650-1700F. Time is more significant at that temperature. Also, it is time above Ac/Ar that counts. Below the critical point, the steel returned to pearlite and slow cooled for what I would guess was an hour at most ( to drop to 1200F).

A 1475F normal soak time, then oven cooling to 1200F will not grow grain or damage the steel.

A new soak at 1475F followed by a quench should yield a fine grain and full hardness.
Click to expand...
Thank you sir. That's what I... er, somebody I mean, ended up doing. Everything turned out seemingly okay. Hypothetically speaking.
 
Hypothetically speaking............ :D this time take coffee , light a cigarette / if you smoke / and enjoy that ten minutes waiting steel to be cooked ... :p
 
You must log in or register to reply here.
Back
Top