Heat Treating 5160...

I ask because if it was from New Jersey Steel Baron I would say yes, you have to do all that, because their steel comes in a very coarsely spherodized condition. Everywhere else seems to come in a finely spheroidized condition. I don't know about TKMS steel in particular. As has been discussed in another thread here today, normalizing is a good idea because most of this material is not true bar stock, it is bars cut from sheets that were unrolled from coils. So there is some residual stress from that flattening operation. Normalizing should reduce that stress, reducing warp in quench. If you minimize the soak time, you shouldn't get much grain growth. So it isn't absolutely necessary to do the thermal cycles.

But this isn't about 5160 as an alloy, getting a different alloy doesn't necessarily mean normalizing and thermal cycling can be skipped, or that they're not a good idea. It's about getting the most out of your heat treat as possible, so the blade can perform at the peak of that material's capability.

If you heat your blade up and quench it, without normalizing, and it skates a file, you may have a pretty good blade. It may have coarser grain than ideal, it may not. It may warp, it may not. It may not perform even though it's hard if the spherodization was too large. It may work just fine.

All this talk about normalizing and thermal cycles are how we can reduce the maybe will-maybe won't in heat treating, because of the unique application knives find themselves in that's not really duplicated in most industrial use of these alloys.
 
I will normalize it. Gonna try it and the HT at night this time so I can see the red better.
Is there any reason I cant or shouldnt normalize it before I grind it. I havent cleaned the scale off that it came with.
My thought process was to normalize it then remove all the scale.
If thats a bad idea let me know......thanks for the advise guys.
Among other things today I learned the temp you temper it at has a direct effect on hardness.
My last blade only hardened the front 2/3 of the blade. I was gonna re HT but had already put an edge on it.
I also had some grinding flaws. I mad a jig and the first side went so well I surprised my self.
I flipped it over and was all over the place. Wasnt until I was on my file jig that I notice the blade was bent.
I straightned it and like you guys were talking earlier when I did my HT it went/came right back.
Even the part of my blade that didnt harden got somewhat harder than it was.
Before HT after I got my edge in .020 range I was dumb enough to give it a gentle swing into the wood of my file jig and it deformed the crap out of the edge.
Lesson learned there.....
 
You can normalize before grinding, sure. If you tune your forge to a neutral or slightly reduction flame it will reduce the decarb significantly.
 
That may have went over my head.... as far as the flame deal. I am guessing you are saying I dont want the weed burner turned all the way up. Maybe when I get it done this weekend I will will post some pics and see what ya guys think.
In order to post pics here do you have to post them elsewhere then rt click and drag over the url. I tried the other day to put one up from my computer with out any success.
 
Knife is profiled.....got one edge ground with 50 grit last night. I wish I could post a pic. My phone wont even let me upload one to my fb today.
The new home grown forge worked pretty good and hope I got her normalized.
I was just gonna heat treat it but I think before I 220 the blade I will give it a couple of thermal cycles.
Just to be clear I am lookin to heat the blade less than what I normalized it at....and the one after that even cooler yet?
Do I need to remove the scale between cycles....or is that not necessary?
Think I am gonna edge quench on the HT.
Sounds like I should try and soak the blade for a bit. I think I can soak it at least 5 min with out an issue.
My muffle seemed to work pretty good.
As far as bringing a knife up to critical.....how fast is too fast....and how long is too slow.
As far as blade particulars its 1/4 x 12" x 1 3/4
Are you suppose to heat the forge up all the way first.....or let the knife heat up with the forge??
Sorry for all the newb questions. I figured it would be better to ask here than start a new thread.
 
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