Programing an oven

smithy

Well-Known Member
I am a new maker that is using 1084. I have a couple of ovens (left over from another life) and they are both programmable. My questions are:

1. In normalizing, can I program a routine that will allow me to take it up to 1600, stop and let it cool for 2 hrs, then take it back to 1500 and let it cool for 2 hours, and then take it up to 1200 and stop, letting the blade cool in the oven?

2. What program should I set up for hardening, the ramp and holding time till I quench?

3. Can I set up a program to temper the blades and, if so, what should it be?

4. Is it easier to use a torch and watch for color as I will only be doing 2-3 blades at a time?

As always TIA...Teddy
 
hi,
i do stock removal and don't normalize 1084. have had no issues.
to harden, I would pre-heat furnace to 1400, add blade, heat to 1475, about 10 minutes at 1475(combination of temperature equalization and soak)quench in fast oil
if you have a second oven to use, preheat to temper temp(i use 350). cool quenched blade to room temp, clean off oil and scale(I use dawn dishwashing soap and green scothbrite) temper for 60-90minutes
hope this helps
scott
 
Teddy,

#1. That is an annealing cycle when you slow cool. Slow cooling is not needed for normalization or grain refinement cycles. But my Rampmaster 3 on the Evenheat can be programmed like this.

You could program it with the stages at different temps the way you describe. The way I program it is to drop 40 degrees per hour down to 800 then shut off.

#2 Ramp full blast to your hardening temp. Say 1500 degrees. THEN put your blade in the oven. The oven temp will drop due to opening the door and the cold blade will suck some heat up dropping the oven temp. Let the oven return to the setpoint. As a rule I give it 10 minutes just to get the blade heated evenly through and consider that zero soak. If I want a soak it is additional time to that 10 minutes at the setpoint. A soak at an accurate temp wont hurt but your 1084 doesn't require a soak. I'd go 12 minutes at the setpoint for a 2 minute soak then pull and quench.

#3 I like to use my oven to temper also. The problem is after quenching the oven will remain very hot. Leaving the door open to cool the oven is bad for the coils and will reduce their life.

When I'm going to quench I preheat the kitchen oven to 250 degrees. High enough to stress relieve the fresh martinsite but not high enough reduce the hardness of the blade. This is just to relieve the stress so I can temper the next day in the Evenheat after it's cooled down.

I program my temper cycle for 5 hours at temp. Put blade in and pull it out after 2 hours. Leave it air cool for 1/2 hour or so then put it back in to finish out the second 2 hours.

#4 Many thing can be done but use your oven for all your heat treating operations. Accurate, Consistant, Repeatable !!!!! That's why you've got the oven ;)

Hope this helps but the programming will be dependent on your individual controller.

-Josh
 
Hey Josh, I cool my Evenheat by opening the door just an inch or so for awhile, then open it on up. I guess I've done this for 5 or 6 years. I also water quench after each temper cycle. That saves a little electricity and helps RA conversion, if there is any. BTW, KC just recently posted that any temper time over a one hour cycle, and two hours total, is non productive. Not harmful, but just a waste of time and power. So one can just do a 1x2 temper program. I am going to try it with the 01. Saves power and time. I believe Roman Landes alludes to that also, but I'm not sure.
 
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I like that idea for cooling the oven Wick. Helping a buddy with a 24" blade tonight so we pretty much don't have any other choice but to do it this way.

I was aware that it's ok to water cool after the temper but was not aware it would aid in RA conversion. I always thought you'd get equal conversion once the blade got down to room temp. Good info to know thanks !

I was taught in general that once your steel is heated through evenly you've accomplished the temper and the extra time is just insurance. Maybe I'll change up to a 1x2 with a water cool in between cycles. That would reduce my oven run time from 5 hours to 2.

Good stuff !

-Josh
 
Caution - the leading cause of element failure is cooling with the door open. It''s not an event thing - happens over time. We all do it - but it has consequences so try not to too often.
 
I like that idea for cooling the oven Wick. Helping a buddy with a 24" blade tonight so we pretty much don't have any other choice but to do it this way.

I was aware that it's ok to water cool after the temper but was not aware it would aid in RA conversion. I always thought you'd get equal conversion once the blade got down to room temp. Good info to know thanks !

I was taught in general that once your steel is heated through evenly you've accomplished the temper and the extra time is just insurance. Maybe I'll change up to a 1x2 with a water cool in between cycles. That would reduce my oven run time from 5 hours to 2.

Good stuff !

-Josh

According to Stacy Apelt, if the RA cools too slowly towards martensite, some will revert back. If quenched, it is locked. The results are not highly significant at all, I think he mentioned only a one or two percent increase in finished martensite but since no harm is done, why not?
As to the oven door. That has worked well for me, but I am aware of the potential harm to the elements. Last time I priced, they were only $30.00 +. To me, it is worth the risk to not have to wait, and my old woman/dear wife bitches if I temper in the kitchen. Not as accurate either.$30 something dollars over 5 or 6 years in exchange for the added convenience and the escape of a brow beating is worth it to me. Everyone else will have to decide for themselves. There is a risk.
 
BTW, KC just recently posted that any temper time over a one hour cycle, and two hours total, is non productive. Not harmful, but just a waste of time and power. So one can just do a 1x2 temper program. I am going to try it with the 01. Saves power and time. I believe Roman Landes alludes to that also, but I'm not sure.

hi,
the reduced temper times is for basic(?) steels. Roman suggested a 30minute temper for 80CRV2. I heat tempering oven to temp, add blades after quench, start timing when last one goes in.
Josh, you mentioned having several furnaces, my thought would be have one for hardening and one for tempering, then you wouldn't have to worry about cooling one quickly.
Scott
 
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