Heating 1084 for Hardening by color. Am I getting too hot??

KnuckleDownKnives

KnuckleDownKnives

Time to make the doughnuts..
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I think I may be getting too hot when heating for hardening. I'm just doing it by color, but are the looks of this am I getting too hot?

 
Color's hard to judge by... I'm a fan of the magnet approach myself in the absence of accurate temp control. Heat it 'till it's a little bit past non-magnetic and quench. Usually appears somewhere between dull orange and bright orange to me, depending on the ambient light.
 
Metalhead0483 said:
Color's hard to judge by... I'm a fan of the magnet approach myself in the absence of accurate temp control. Heat it 'till it's a little bit past non-magnetic and quench. Usually appears somewhere between dull orange and bright orange to me, depending on the ambient light.
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Yes, I know the non mag test, but for 1084 it's 100* more than that, I've got it down to when it's non mag by color and I am taking it to the next full color then quench. Heating was done in a darker corner of my shop so the color in the pic is real close to what I was looking at when heating.
 
The advice I always read is to heat treat a few test pieces and then break them to examine the grain.
 
If it is anywhere near as bright as it looks in that picture, you are way too hot!! I use a digital oven and in a well lit shop it appears JUST above red. A mix of red and orange. But without some sort of thermocouple you are just better off using a magnet than attempting to judge color.
 
I'll follow this with interest, but I too think that is way too hot. I always though a low to mid orange was about right.
 
Judging by the colors that I see on this picture color in the circle is the one I see when steel past non-magnetic +

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BKT said:
If it is anywhere near as bright as it looks in that picture, you are way too hot!! I use a digital oven and in a well lit shop it appears JUST above red. A mix of red and orange. But without some sort of thermocouple you are just better off using a magnet than attempting to judge color.
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Magnet and blade in tube , hard to overheat .In tube you can more clear see color , no flame from torch and more equal temperature of the whole blade :thumbup:
Tomorrow I will try to take picture , I wonder how will turn colors in the picture .....
 
Sounds like it's time to invest in a forge and put a thermocouple in it.

So what now with my 4 blades heated at this temp and quenched in canolla?
 
What type of steel? What is your normalization process like? Lots of factors.

If you can spare one, break one in half and inspect the grain. That will tell you if they are safe or not most likely.

EDIT: Sorry I saw you said 1084. That is good. it is much more forgiving than other steels when it comes to temp control. I would say go ahead a finish one out and do some testing. Edge holding, stabbing, drop on concrete. See if its up to your standards. That is the only true way to know. We are looking at a picture on the internet here and it could be in real life it was much closer to the right temp than we can tell from a picture. I would guess it is ok , maybe not 100% optimal, but probably ok.
 
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I thought I knew how to do that until I got a temp controlled electric furnace. Lo and behold, 1500 degrees is still in the red range, barely creeping up on the dullest orange. No wonder a lot of my early file knives were too brittle, I was quenching from 1600+
You need dim ambient lighting, too, if you're going to do it in a forge, daylight makes it really hard to estimate.
 
BKT said:
What type of steel? What is your normalization process like? Lots of factors.

If you can spare one, break one in half and inspect the grain. That will tell you if they are safe or not most likely.
Click to expand...

1084, and I don't have one. I purchase it from Aldo's and every post I've read says to grid it, heat it quench it and temper it. Nothing about normalizing. I's rather not break one, but maybe heat another piece of metal to the same temp, temper it the same and then break it.

If they are way over heated what can be done to them to fix?

Edit for those helping: It only took me less than 2 mins to get to temp and quench, so it was not at this temp very long at all.
 
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Yep just HT and break a coupon. Maybe 2x3 or something to check grain.

I'm starting to do AEB-L in my shop and I will be going through the same thing. I thought about just grinding an edge on one side of the coupons to do some edge performance testing before snapping them in the vice to look at grain.
 
if you are going slightly brighter than non magnetic, i think you are fine. but you described "one full shade" brighter, its hard to tell what you mean by one full shade.
 
I don't think anyone here can make a sound judgement based on a picture. Colors will be different, depending on ambient light, let alone how cameras and monitors capture and display that color. Ever go into an electronics store and see the difference between pictures from the TVs on display?

There is actually a simple(ish) answer. Learn to recognize decalescense and recalescense. It is the only true "visual sign post" of transformation and is not that hard to detect with a little practice. Decalescence is what you are looking for but observing the much easier to see, recalescence will help show you what to expect. Do not confuse the two, though... decalescense happens as temperature increases, where, recalescense happens as it cools down... and at a much lower temperature than the former.
 
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Rick, I've read about that and will do some more studying. Thanks all for the info. Waiting on my quench oil to heat up and doing a test coupon as soon as it gets to 130.
 
Well so much for that. Wife decided to use the rest of my propane heating the shop today on her day off to have a warm place to have a cigarette and left the heater running all day long using all of my gas up. Have to wait till the weekend. Grrrrrrr....
 
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