delayed on tempering. do i need to start over?

N

ncnurseryman

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Jul 2, 2012
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I was working on a knife using 1095 steel after heat treating I wasn't able to fully finish the tempering process. so now its been a couple of days and it hasn't been fully tempered in the oven. do I need to start over and and reheat and qench and them temper all over again or can I just finish the tempering? thanks
 
Just continue. By using the term "fully tempered", I would assume you gave it a snap temper, or one cycle of temper. It should be fine until you can continue.
 
Yeah, it's been in the oven for one hour at 450 once, then a second time yesterday, but I was delayed again for the third time.
 
It kind of depends, doesn't it?

If you're aiming for the stars, no, there are reasons why it's not ideal.
If you're selling it as a knife produced by the best processes known to man, it's not quite as good as it could be.
If it's something for daily use, the chances of it mattering are slim to none. If it was a knife I was making for my own use, I wouldn't care a bit.
Stacy (Bladsmith) and others have discussed this at length in prior posts, and the reasons why you don't pause the tempering process- it may be in the stickies.
 
One of th reasons for immediate tempering is that the internal stresses from quenching may crack your blade while its sitting on the bed-post over night.
 
elementfe said:
It kind of depends, doesn't it?

If you're aiming for the stars, no, there are reasons why it's not ideal.
If you're selling it as a knife produced by the best processes known to man, it's not quite as good as it could be.
If it's something for daily use, the chances of it mattering are slim to none. If it was a knife I was making for my own use, I wouldn't care a bit.
Stacy (Bladsmith) and others have discussed this at length in prior posts, and the reasons why you don't pause the tempering process- it may be in the stickies.
Click to expand...

I believe that you have misread something. There should be no unnecessary pause getting the blade into it's first temper. After that, the second, or third temper can wait until whenever.
 
as for carbon steels there REALLY... is not a big deal with leaving the knife out for a day even with out tempering at all. when you read "temper immediatly" this is mainly because if there was any stressers in the steel it could crack over time at the "as quenched" state. but if you did a normalize cycle before quenching or if the knife was made via stock removal chances are you could leave the blade out for days with no issues. there are some knife makers that use carbon steels and it is part of there heat treating process to let the blade sit over night at room temp ,and or, in the house freezer (AKA)=chad2 :D.

now! with stainless steels this is not the case your heat treating process should look like a roller coaster of temperature changes with very little sit times. mins at the most. dont confuse sit times with soak times.
 
I beg to differ. With most carbon steels an immediate temper is almost mandatory. There are a few that you might risk going untempered for for a short term, such as 01, but the risk is still there. Risk time with others, such as 1095/1084, may be measured in minutes, whether you normalized or not.
 
Thanks for all the input. I did finish the tempering and it seems ok, now I haven't done any testing on it. It always amazes me how many different methods exist for heat treating and such. All part of the fun.

Does anyone know what creates the blue purple color on the blade? Too bad those colors don't stay there when polishing. They are cool looking.
 
Heat + oxygen if the steel is bright and clean. Those colors would indicate an over heat for temper, were you using a torch, forge heat, or an atmosphere controlled oven and a perfectly clean bright blade, but when using a common type HT oven with a trusted heat control, it is usually contaminates on the steel, or in the ovens atmosphere. Finger oils, ect. If you know and trust your thermocouple heat control to be reasonably accurate, it is of no concern.
 
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