Specific question regarding austenitizing temperature and holding time.

L

Laredian

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May 27, 2013
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So this has been bugging me for some time now and I wanted to check with you guys on whether I am overthinking this or not.

Let's say I am heat treating a small AEB-L blank in my Evenheat:

For austenitizing I run two segments: one set at 9999 ramp temperature to get the oven up to temp as quickly as possible and then hold it there for 30min to equalize the oven temperature. Then I put the blade in for the second segment set to the austenitizing temperature with a hold time of 15min for AEB-L in this case.

Now my question is basically this: when putting the blade into the oven between segments 1 and 2, it still obviously takes a certain amount of time (depending on the size of the workpiece) to reach austenitizing temperature. Do I need to add that time to the 15min hold time or is that time negligible for small workpieces like knives?

Best regards and thanks in advance for taking time to answer my question.
 
I start soak time once oven has fully rebounded after placing blanks in oven. If you are concerned a little extra soak is not going to cause any issues.
 
Laredian said:
Thank you for the quick answer. In your experience, is it enough to add about 2 minutes give or take depending on the size of the workpiece?
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An idea might be to check your oven and see how long it takes from the time you close the door with blade in oven until the oven settles on temp. See how many minutes that is for YOUR oven. Note this is after the oven has stabilized at temp for the 30 minutes before putting blade in oven. Realizing putting one blade in vs putting 4 or 5 blades in will change the amount of time.

I'd like Hoss to comment on this, but I think with AEB-L calling for a 15 minute soak at temp, it won't hurt anything if it soaks for 20 minutes at temp - or even 25 minutes. Hoss - please comment about the max time at austenitizing temperature.
 
Steel is a lot more sensitive to temperature than it is to time.

It’s more dangerous to have 5 minutes too little time than 5 minutes too much time.

15-20 minutes soak time at full temperature is fine for AEB-L, more time is needed for higher alloy steels.

Larger knives require longer soak times because they do not rebound as quickly as the furnace.

Hoss
 
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