How do I re heat treat

KnuckleDownKnives

KnuckleDownKnives

Time to make the doughnuts..
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Feb 12, 2015
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Ok so I made I knife (I know from an old file buy some known steel) and heated till non magnetic and quenched in oil baked in and oven at 450 for an hour cooled and another hour at 450. This worked well with the first on I did. Had a nice golden color and a file just skated across it. This one not so much. Same type of file. Old Nicholson USA mill file. How do I go about re heat treating and trying for better results? Don't think I just go back to critical and quench but could be wrong. Still real noob and see HT is going to be a major focus one I get my grinder finished as I have some good steel and don't want to waste it till I'm capable of a decent HT.
 
Well let me add this. The first one I did it was cold as heck out and did not preheat the oil and heated with a oxy accetalyn torch and right into the oil after maybe 30 sec to a min at non magnetic. This time I pre heated the oil and it was already hot out. First one oils was probably 40 deg. This one prob heated oil to 150. Don't have a thermometer yet.
 
I haven't used Nicholson files myself but many folks have. Hopefully someone who has used them will chime in. I THINK those files are either 1095 or W2. Both are hypereuticoid steels and heat treat similarly. Check out the heat treat stickies for those steel types for a place to start. I doubt you will be able to achieve the kind of temperature control you will need using a torch. It is recommended to use a precise temperature controlled oven to keep the correct temprature for the prescribed soak times for these steels. I have had great results with 1095 in a charcoal forge but it's tricky. I think the main reason that it is recommended so much that you use known steels is so you can know how it will behave especially during heat treatment. When I use unknowns I do quite a bit of experimenting to nail down a heat treatment that I'm happy with.
You can go ahead and try to heat treat again but I would normalize the knife again first myself. And yes, preheat your oil. I've found 130 deg works well for me. Hope this helps!

-Colin
 
GrenfellsBrutalForge said:
I haven't used Nicholson files myself but many folks have. Hopefully someone who has used them will chime in. I THINK those files are either 1095 or W2. Both are hypereuticoid steels and heat treat similarly. Check out the heat treat stickies for those steel types for a place to start. I doubt you will be able to achieve the kind of temperature control you will need using a torch. It is recommended to use a precise temperature controlled oven to keep the correct temprature for the prescribed soak times for these steels. I have had great results with 1095 in a charcoal forge but it's tricky. I think the main reason that it is recommended so much that you use known steels is so you can know how it will behave especially during heat treatment. When I use unknowns I do quite a bit of experimenting to nail down a heat treatment that I'm happy with.
You can go ahead and try to heat treat again but I would normalize the knife again first myself. And yes, preheat your oil. I've found 130 deg works well for me. Hope this helps!

-Colin
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I was thinking I may need to increase the soak time, just kinda weird I had great success with the first one and not with the second. I guess that's just part of it. When I did the tempering and didn't get the nice even golden color I figured I'd be redoing something.

Problem is I'm getting hung up on the "Normalizing". Still tying to get familiar with all the terms and what they mean.

This is what I am going to try for the actual HT from the stickies by Stacy"

"Basic 1095 HT - Foolproof:
Heat evenly to 1475F for 10 minutes then immediately quench in fast oil (fast enough to cool the steel through the 1200F-1000F in less than .5 seconds). For simplicity sake cool to at least 150F before tempering. This should get you a full 65HRC hardness with no problem, tempering should be done without delay. Tempering should be for 2 hours at the temperature to reach the desired final hardness. 400F to 450F is a good range for knife blades."

What do I need to do do normalize it before the above process? This is what I think I'm overlooking for "1095" steel. That sis what i'm "assuming" I'm working with. I read his post on the 3 stage normalizing for 1084, but spherioid and 1095 is Hypereutectioid so I'm sure the normalizing process MAY be different.

Edit: I'll be happy if I can just get a little bit better results for this as it's just going to be given to my step son. He probably won't take very good care of it but I would like to give it to him the best that I can.
 
Have a look at Kevin cashin's post "working the three steel types" found in the heat treat stickies. It gives a great explanation of what's going on during heat treat. Hypereuticoid steels are the last covered and the importance of soak time with these steels is explained.
Normalizing is done to relieve stresses in the steel, prevents warps and cracks from happening during the quench and reduces the grain structure in the steel.
This is what I do, others may do it differently and get better results but this works for me. I don't get cracking, warping is minimal and grain is nice and fine. Good temprature control is your friend here, grain grows quickly once you go above critical.
First I heat up just to critical and remove the piece and let it cool back down to black and then some.
Next heat to just BELOW critical and take it out and cool
Next heat to below the previous heat and let cool to room temp.
I judge temprature by color in low light, and while it isn't the most ideal situation, it works for me or at least I'm satisfied with the results.
After you quench, but before you start tempering is when you want to test the blade with a file to see if it hardened. The steel will have a decarborized layer on it after the quench which the file will kind of bite but try it a few times in the same spot and you should be able to feel the difference.
What are you using to temper your knives? If your using a kitchen oven or toaster oven, you should put an oven thermometer in with the knife to see what temprature your actually getting. My oven is all over the place when it starts. The other day I set it to 400deg and when it said it was heated up I checked and it was only at 300. I had to try a few times to get it where I wanted. Keep checking to make sure the temp doesn't soar on past where you want or you will have ruined your heat treat and have to start over.
Also, any oil or other contaminants on the steel will affect the colour you will see.
Best way to know if you got to where you wanted to be is by doing a hardness test either with a machine (better) or hardness files. I don't have any of that stuff but I file my bevels so when I thin them down after HT I can tell if they hardened up the way I wanted them.
Again, hope this helps!!

-Colin
 
Its possible your HT is ok but you have a layer of decarb on the blade you havnt ground off yet. Very common issue. Your file is biting into the decarb layer, grind to good metal and recheck
 
Back to the question; As far as re-heat treating, I just re-heat treat. You don't need to do anything special.
 
Willie71 said:
Here's a recent discussion on W2, very similar to 1095. There have been quite a few discussions on these steels in the past few years, and this is the accumulation of what people have spent years learning.

http://www.bladeforums.com/forums/showthread.php/1397069-W2?highlight=W2+heat+treat
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Thanks, I have read that post and will re-read it and soak it in. I actually have an old Nicholson Black Diamond after research leads me to believe that's what it is W2. Appearance wise from the age it is quite different steel than the one I'm working on now. The one on the left has been weathered for about 5 years and is like the one I used to make the one I'm referring to, the one on the right (Black Diamond) has been sticking in a tree for at least 30 years says the guy who gave it to me and stuck it in the tree when his now 45 year old son was a teenager.



Spalted said:
Its possible your HT is ok but you have a layer of decarb on the blade you havnt ground off yet. Very common issue. Your file is biting into the decarb layer, grind to good metal and recheck
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Actually that is when I checked it. After the HT attempt and temper I did some grinding to clean up the black and bring it to final dimensions. Only have a little more to grind before I was ready to get on the handle.
 
Don Hanson III said:
Normalizing is a good practice, but in this case it is not needed. Just heat and quench again.
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Thanks for the reply Don. I'm going to give it another go in the next few days.

Tied up right now fixing a buddy's 4 wheel drive in his side by side and I'm catching h#ll... Seems every part is held together by rust. :mad: :thumbdn:
 
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