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Yeah, for choppers and large Bowie's, better use 1474-1500°f austenizing and somewhere between 375-392°f temper. 

For kitchen knives, edc's and razors, 1550-1575°f austenizing and 330°-375° temper seems best. 

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Has anyone done any testing on these numbers? I am about to heat treat some 80crv2 blades (small blades, under 3 inches) and just wondering if there was a consensus... 

My thoughts from what I read above:

Normalization:

1) Slow climb to >1600F

2) Slow climb to 1550F

3) Slow climb to sub critical (1420F)

Quench:

1) 1550-1575F to Quench (I'm using warm oil)

Temper:  1-2 hours of each of the following. (I didn't see a consensus here - so this is my thought based on what I read?) 

1) 350

2) 365

3) 375

This should yield a blade in the 61-63 hrc range. 

Any thoughts on a homemade anti-scale compound (I'm hoping to heat treat soon and don't want to wait for an order of ATP-641 to come in), does this help prevent decarb too?

Let me know if I'm totally off here and please address anything I should change.

I'll report back my results. I have a couple blades I don't like and will probably run them first and break them. 

Thanks

Adam

 

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Those temps sounds right but the resulting hardness is a bit high. If you want around 61hrc, don't go above 350°f.

This steel decarbs more than others because of the higher aus temp and hold time. If you don't use ATP, the longer the soak, the thicker layer you'll get. 2-3 minutes is enough imo.

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@aweller I have heard of people using "Boric acid" as "antiscale" Its basically roach killing powder that you can buy for cheap at any local hardware/big box store. 

I have not tried it. This is just what I have heard about on the "internet" . 

There is also this recipe I got from another "Forum"

"Boric acid and alcohol is the standard cheap and easy anti-fire scale dip for our industry ( goldsmith). I have a 50 pound barrel of it.
It also works well as a fluxing agent when mixed with borax and a bit of powdered charcoal.
As to making HT anti-scale, mix it with alcohol and satanite. Shake up the bottle and apply a thin wash. It will dry and coat the metal, preventing scale.Let dry well before HT. Removal can usually be done with washing in hot water, or soaking in mild acid ( vinegar works fine).A post HT acid soak is usually desirable for several reasons anyway.

What I have been able to reverse engineer from using Turco, is that it is a borate with red/brown/yellow ocher mixed in. There is also some sort of colloidal carrier. Ocher is known as goethite, and is nothing but iron oxide clay ( basically ,red clay). I made a batch with boric acid, borax, satanite and ocher, with gum tragacanth as the binder, and it worked identical to Turco. I used a mixture of red and yellow ocher, since I have both on hand. Chemically, the ocher, which is an oxide of iron (mostly Fe/2-O/3), acts as a reducing agent. The various colors of ocher are just the amount of hydration, and are identical otherwise. Yellow is fully hydrated, brown is partially, and red is anhydrous.

Another cheap and very useful anti-scale is plain water and satanite mix. Make a thin slurry and put a wash coat on the blade. Dry it with a hair dryer, or let it air dry. Another thing to try would be a slurry of potters clay.


If you wanted to make a batch of anti scale try this (Quantities are in fluid oz.):
( This is off the top of my head, so feel free to tweak it as desired)

5oz boric acid (roach powder)
3oz borax ( 20 mule team is fine)
8oz denatured alcohol ( the cheap paint store variety, not the drug store stuff)
2oz satanite ( our old refractory friend)
3-4oz ocher (any color ocher - finely sifted dried red clay would probably work)
3-4oz gum tragacanth ( bottle of leather edge dressing)
water

Mix,adding additional alcohol until it becomes a well mixed thick paste.Add water until it becomes a slurry ( I think it needs some water to allow proper hydration and solution of some ingredients). Try it on a piece of steel to check results, and adjust the ingredients as needed. Keep in a tightly capped container,away from heat. Shake well each use, and paint it on with a small brush, or dip the blade and let the excess run back into the container. A batch should last for a long time.

Do not use above 1600F as the borates will become corrosive."
 

Edited by JASON VOLKERT

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4 hours ago, Joël Mercier said:

Those temps sounds right but the resulting hardness is a bit high. If you want around 61hrc, don't go above 350°f.

This steel decarbs more than others because of the higher aus temp and hold time. If you don't use ATP, the longer the soak, the thicker layer you'll get. 2-3 minutes is enough imo.

I don't think I need it that hard, but I'll try sticking below 350.

2-3 minutes is about the longest I can hold a temperature in the propane forge, so I hope that's enough. 

2 hours ago, JASON VOLKERT said:

I have heard of people using "Boric acid" as "antiscale" Its basically roach killing powder that you can buy for cheap at any local hardware/big box store. 

Not sure if we have roach powder here (not an issue where I live - roaches don't seem to appreciate the sub zero temperatures) <_< but I'll check when I go by the hardware store today.... If they have some I'll give it a try, otherwise I might just mix up some satanite and try a thin wash. 

Thanks!

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Well I gave it a run on a throw away blade. I followed the schedule I posted above with the exception of the tempering which I dropped below 350 per Joël's recommendation. I haven't completed the tempering yet, so there is more to come. (I'm kinda double posting because this is all in my WIP post as well, hope that's okay)

After normalization there was a thick layer of scale ( I didn't use any anti-scale coating, no luck on finding Roach killer at the hardware store)

IMG_5556.JPG

After quench the file bit pretty good

IMG_5559.JPG

but after a quick grind I got the file to skate

IMG_5563.JPG

I broke the tang to see the grain. Again, sorry for the picture quality, I took it through a magnifying glass. Let me know what you think, or if you need a better picture. This is about a 1/4 inch wide.

IMG_5560.JPG

closer?

IMG_5561.JPG

I plan on breaking the blade after temper to see what it looks like too, so more to come.

Thanks

Adam

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The grain could be better.  It's not terrible, but it could be smaller.  How many normalizing cycles did you do, and did you soak before quenching?

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The grain is a bit large. Has this area of the tang been through the same heats than the blade? If so I'd add an extra normalization cycle or two.

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1 hour ago, Alan Longmire said:

The grain could be better.  It's not terrible, but it could be smaller.  How many normalizing cycles did you do, and did you soak before quenching?

Three normalizing cycles, minimal soak 1-2 minutes max. I do let it cool to black, still hot but definitely black in a dark room.

To answer your other questions the baffle tube is almost completely closed off on one end - there is a 1/4 inch hole in the back plate. I’ll try closing that off, and try the charcoal you mentioned in the other thread, thanks!

1 hour ago, Joël Mercier said:

The grain is a bit large. Has this area of the tang been through the same heats than the blade? If so I'd add an extra normalization cycle or two.

The tang was probably a few degrees hotter than the blade given it was closer to the burner in the baffle tube, I’m going to break the blade itself as well - so I will post that too. Does it matter that I’m breaking it after tempering? 

 

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36 minutes ago, aweller said:

Does it matter that I’m breaking it after tempering? 

It doesn't but tempering is useless if you plan to break the blade. It just makes the blade harder to break and the break line won't be as clean. 

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36 minutes ago, Joël Mercier said:

It doesn't but tempering is useless if you plan to break the blade. It just makes the blade harder to break and the break line won't be as clean. 

I kinda want to see what the tempering accomplishes. How much harder it is to break and how much deformation it introduces...

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It sorta makes sense but the resulting toughness added by the tempering will be biased by the larger than should be grain size. You should tune up your grain before doing tempering tests.

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I agree with Joel on that.  Tempering that blade isn't going to tell you a lot about how good grain size will perform.  

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Good point. I wont worry about tempering yet. I'll adjust, redo and let you know how the next run turns out. 

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1 hour ago, Alan Longmire said:

I agree with Joel on that. 

Yay! After so many questions, I start getting things right :lol:

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Second run. I think it looks better. I changed a few things. closed up the 1/4" hole at the back of my baffle tube and added a chunk of charcoal in there during the normalization and quench. All but eliminated the scale. There was minimal decarb, wondering if it was the "down" as I lay the blade in the tube on it's side. Maybe I'll try to figure out how to make a stand so it rests on the spine with the blade up. 

Here was my set up this time. I turned the whole forge around so the hot zone in the baffle tube was in front of the blade (not involving the tang), the blade sits directly below the thermocoupler. 

IMG_5569.JPG

Almost no scale and minimal decarb per file test and grinding

IMG_5570.JPG

and here is the cracked blade, to my untrained eye this looks considerable better than the prior test. The ruler is in cm.

IMG_5574.JPG

Any thoughts?

Thanks.

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It looks like your camera was focusing more on the ruler than the end of the tang but off hand I'd say that it looks a lot better.

Doug

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Yep, that's what it's supposed to look like!  B)

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Thanks all, I'm liking this setup a lot better. I might tweak a few things. I'll try to get to another blade tonight after work and take it all the way through heat treat. 

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Here's a test piece I've done today. 1575°f held 5 minutes. I can barely see any grain. It took a good 3 pound hammer hit to break the piece in two. The upper part was sent flying and hit the wall 30 feet away. Tough stuff...

 

IMG_20190527_161810.jpg

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Grain?  I don't see any grain...;)

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On 5/27/2019 at 2:03 PM, Joël Mercier said:

Here's a test piece I've done today. 1575°f held 5 minutes. I can barely see any grain. It took a good 3 pound hammer hit to break the piece in two. The upper part was sent flying and hit the wall 30 feet away. Tough stuff...

 

IMG_20190527_161810.jpg

Did you temper?

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