wtf is going on with this steel?

[Arathol]

Tried to darken a blade with FeCl, something very unexpected happened.
Supposedly 1084 steel, sanded with 220, 400, 800, 1000 grit. Lots of splotching, some spots that just won't oxidize. This is not the first time I've done this but this is the first time I've seen something like this. Its almost like there is some sort of contamination in the steel. I sanded it off did it couple times with the same result. On some of the spots the FECl was just goo that wiped off leaving nearly bare spots underneath.
Any Ideas?

Bare steel looks like this after stripping, there is an odd outline thats on both sides of the blade.

 

[Stacy E. Apelt - Bladesmith]

Most of that appears to be decarb. Other spots may be either decarb or scale forged deep into the blade.

Was it forged?
How much was it ground after HT?
How well was it cleaned prior to etching?
How long was it etched? What concentration FC? How old is your FC?

 

[Arathol]

Most of that appears to be decarb. Other spots may be either decarb or scale forged deep into the blade.

Was it forged?
How much was it ground after HT?
How well was it cleaned prior to etching?
How long was it etched? What concentration FC? How old is your FC?

Not forged, stock removal on a belt grinder according to the maker.
No idea how much it was actually ground or what was ground when, but the tang is .138, the thickest part of the blade is .126.
It was sanded thoroughly and well cleaned. I stripped it twice and each time got the same result.
It was in the FC for only a few minutes, just long enough for the spots to appear. I tried leaving the FC on a couple of the spots for 20 minutes with no effect.
The FC is not old, I used it a couple weeks ago to do a couple other blades with no problems.
The two round spots just won't take the etch no matter what-
Before FC applied

20 minutes later

When sanded to 1000 grit, the larger oblong spot looks almost like a hamon line, with the steel actually having a different appearance.
It also seems to etch differently, it got a lot darker and much faster
This area is what you see in the above pics thats nearly black

 

[Stacy E. Apelt - Bladesmith]

Is this a blade you bought pre-hardened? Was it a finished blade?

 

[C_Claycomb]

Hi,
It wasn’t obvious in the first post that you hadn’t made this knife yourself. Everything about th3 post was in line with what many new packers would have posted.
Anyway, my money is on a torch or forge heat treatment, uneven heat and not agitating the quench. It’s not going to be contaminated steel. Those perfectly round spots are not a shape that could survive all the rolling that steel goes through to make plate/sheet.

Those perfectly circular spots make me think of bubbles in boiling quenchant.
I haven’t used 1084, but I have seen similar shapes on O1, treated in a forge, and not moved in the quench oil. Looked like a boiling patter that didn’t sand off.

How does it cut and sharpen? Any difference in hardness between the two edge tones?

 

[Arathol]

Is this a blade you bought pre-hardened? Was it a finished blade?

Finished knife bought from maker

Hi,
It wasn’t obvious in the first post that you hadn’t made this knife yourself. Everything about th3 post was in line with what many new packers would have posted.
Anyway, my money is on a torch or forge heat treatment, uneven heat and not agitating the quench. It’s not going to be contaminated steel. Those perfectly round spots are not a shape that could survive all the rolling that steel goes through to make plate/sheet.

Those perfectly circular spots make me think of bubbles in boiling quenchant.
I haven’t used 1084, but I have seen similar shapes on O1, treated in a forge, and not moved in the quench oil. Looked like a boiling patter that didn’t sand off.

How does it cut and sharpen? Any difference in hardness between the two edge tones?

It does cut ok, but doesn't seem to want to get as sharp as it should, just barely shaving sharp, and a bit draggy at that. The edge was rolled when I got it, but that is another story that I am discussing with the maker....... The edge seems rough when cutting, it won't stay as sharp as it should either, and its not due to a wire edge, I've been round and round with that. It will slice printer paper easily. Feathersticks...not really even though it should. Now that you mention it, the tip doesn't seem to cut as well as the rest of the blade, but I just put that off to geometry. As far as sharpening, yeah the tip seems like its a bit softer and leaves more residue on the stone.
I have no idea how this guy does his blades other than he says he does the HT and temper himself.
I can see the bubble idea, but why would that prevent etching? Those two round spots in the right light look almost like when you put a dowel in a piece of wood and sand it flush, two perfectly round shiny spots.
It seems that almost half the blade is etching differently from the rest. As you can see in the pictures, on parts of the blade it just wiped off with a paper towel and the tip end is much darker than the tang end. Its just odd.....

 

[Stacy E. Apelt - Bladesmith]

From everything you have said, I go with decarb for most of the problems. A bad HT is another good possibility (which may also cause the decarb).
The spots could be from many things, including poor steel, or poor procedures.
You said the blade is stock removal, but are you sure? Was the billet forged from a larger piece of steel and then ground to shape? Many people in some parts of the world call all sorts of available mid-carbon steel 1084. That does not make it so.

Not knowing the maker, where you or him live, or any details, it is hard to pin any exact cause. Lets see if we can narrow it down some more.
Also, do you make knives? What equipment/method did you use to sand the blade down? Did you take it down heavily with 120 or 220 grit, or just go with a higher grit to make it shiny and smooth?

You don't have to name the maker if you don't want to but please tell us where he is from and anything you know about him, his equipment/methods, and his experience. Is he a well known maker, or just someone selling online.

I have seen similar problems on knives that were heavily decarbed. After grinding the bevels down considerably, the edge got hard and the whole blade etched evenly. In other cases, I took the blade down to clean metal and re-did the HT. That usually solved the issues.
There have been many past threads with issues like yours that ended up being mainly decarb.

Give us a few more of the details above and let's try to get to the bottom of this.

BTW, is there a knifemaker near you who is known to make good knives and use good equipment? He may be able to regrind the bevels and see if that is the issue.

Last thing - You have been around for 22 years. Fill out your profile so we know where you live,]. That helps us a lot. The other info in your profile can also tell us a bit about you.

 

[Arathol]

From everything you have said, I go with decarb for most of the problems. A bad HT is another good possibility (which may also cause the decarb).
The spots could be from many things, including poor steel, or poor procedures.
You said the blade is stock removal, but are you sure? Was the billet forged from a larger piece of steel and then ground to shape? Many people in some parts of the world call all sorts of available mid-carbon steel 1084. That does not make it so.

The guy is a small time maker in Michigan, he has been active maybe 4 years. He says he grinds his blades. No idea about the billets. He says its 1084, I have nothing else but his word to go on.

Not knowing the maker, where you or him live, or any details, it is hard to pin any exact cause. Lets see if we can narrow it down some more.
Also, do you make knives? What equipment/method did you use to sand the blade down? Did you take it down heavily with 120 or 220 grit, or just go with a higher grit to make it shiny and smooth?

The maker uses a belt grinder to make his knives according to him. He mentioned the above grits when referring to using a 2x72 belt grinder to sharpened it.
No, I don't make knives. I used the same grit sizes to do the edge and clean up the blade (don't ask, long story, another problem with the maker). Everything done by hand, no power equipment, actually got to down to 2000 grit with decent finish. Nothing heavy, just clean it up a bit cosmetically because there were some lines from the belt grinder still visible. Started with 220 and worked up until it looked better than it did before.

You don't have to name the maker if you don't want to but please tell us where he is from and anything you know about him, his equipment/methods, and his experience. Is he a well known maker, or just someone selling online.

Not a well known maker, a retired guy that started making knives and opened a small forge. He has an on-line store.
I'd rather not say who until I get this and other issues resolved with him.

I have seen similar problems on knives that were heavily decarbed. After grinding the bevels down considerably, the edge got hard and the whole blade etched evenly. In other cases, I took the blade down to clean metal and re-did the HT. That usually solved the issues.
There have been many past threads with issues like yours that ended up being mainly decarb.

Give us a few more of the details above and let's try to get to the bottom of this.

BTW, is there a knifemaker near you who is known to make good knives and use good equipment? He may be able to regrind the bevels and see if that is the issue.

Last thing - You have been around for 22 years. Fill out your profile so we know where you live,]. That helps us a lot. The other info in your profile can also tell us a bit about you.

Doing a regrind might be problematic due to the design of the blade. Its a Kephart, but the blade has a tall rhombic profile. Its ground from the centerline to the edge, and from the center line to spine is also tapered. I'm not sure if any serious grinding could be done without destroying the blade cross section.
Not sure about knife makers near me. I'm not aware of any though there might be. I'm in central CT.

 

[Stacy E. Apelt - Bladesmith]

Yeah, it sounds like the issue is decarb and maybe a bad HT. Pretty much all blades are ground on a belt grinder, but many are forged to shape first.
If he uses a forge to do HT, that can cause lots of issues. With a forge HT the decarb can be pretty deep and require removing several thousandths of the entire surface after HT. While "cleaning it up" may bring the steel to a smooth and shiny look, the decarb is still there. Etching the steel shows where the carbon steel is exposed (which etches dark) and the decarb steel is (which etches gray).

Decarb on the blade's surfaces isn't a problem beyond looks. However, serious decarb along an edge, or an improper HT that didn't harden the entire edge is a problem. A forge HT can also overheat some area severely, especially the tip,, which can cause many issues with the grain and other things.

I would have the maker replace it with a new knife. If he isn't willing to do that, then you may just have to settle with sanding it back to shiny metal and leaving it that way.

You may also want to choose another maker in the future. New England is full of knifemakers.

 

[Arathol]

Yeah, it sounds like the issue is decarb and maybe a bad HT. Pretty much all blades are ground on a belt grinder, but many are forged to shape first.

This guy says he makes blades using stock removal, so I'm assuming he just grinds them from a piece of flat stock.

If he uses a forge to do HT, that can cause lots of issues. With a forge HT the decarb can be pretty deep and require removing several thousandths of the entire surface after HT. While "cleaning it up" may bring the steel to a smooth and shiny look, the decarb is still there. Etching the steel shows where the carbon steel is exposed (which etches dark) and the decarb steel is (which etches gray).

Decarb on the blade's surfaces isn't a problem beyond looks. However, serious decarb along an edge, or an improper HT that didn't harden the entire edge is a problem. A forge HT can also overheat some area severely, especially the tip,, which can cause many issues with the grain and other things

He apparently uses a "temperature controlled heat furnace" in his words and uses ASM standards for heat treating.

I would have the maker replace it with a new knife. If he isn't willing to do that, then you may just have to settle with sanding it back to shiny metal and leaving it that way.

You may also want to choose another maker in the future. New England is full of knifemakers.

I'm still waiting for a response but not holding my breath on this one. He seems a bit reluctant to admit that this knife might have issues even though he says it has a one year warranty. From what communications I have had it doesn't seem like he has a lot of experience and doesn't seem to know things that he should know as a maker. For instance, I found out after the knife was delivered that he had just recently got training on how to sharpen a knife from a "professional knife sharpener".....the edge was atrocious. It looked like it was done at a local mower repair shop, and a noticeable part of the blade near the tang had been ground to a recurve........after I bought it. I sent him before and after pics of the knife when I got it, his reply was "I don't see the problem"..... I had never dealt with him before and I won't be doing any more business with this guy.

 

[S obsessed]

Some of the 80 series steels from some suppliers over the years have not responded well to heat treat as they come. They needed to be taken to a very high forging type of temperature to reset them and then normalized and other refining steps taken before quenching. When I have done this so I can heat treat from a pearlite type of structure I will do a high heat soak in the forge which if high enough will blister the steel some with scale and if it doesn't get ground off before one finally makes it to the quenching stage it can cause these types of circles to appear where the blisters were. The steel is still hardened under there but because of the thermal cycles there is more decarb than a basic heat treat from the "as is" annealed structure and will need more grinding to get through it all before etching. Hand sanding isn't going to do it unless you spend a lot of time with coarse grits. The maker may have heat treated in this way with grinding before hand and not breaking through all the decarb after heat treat. Same with the edge. It may just need to have more material removed before establishing. I am guessing it is fine but needs some more material removed.

 

[Stacy E. Apelt - Bladesmith]

I agree. The maker should be glad to regrind te blade and make it good. He probably will have to remove the scales and redo the entire knife to do this. He may choose to make a new one from scratch and check it carefully before shipping (which is what every knifemaker I know would do).
If he will not, then you know that he isn't the fellow for your next knife order.

In hate to use a trite saying, but often when looking at a lower price, you get what you pay for.

 

[Arathol]

I agree. The maker should be glad to regrind te blade and make it good. He probably will have to remove the scales and redo the entire knife to do this. He may choose to make a new one from scratch and check it carefully before shipping (which is what every knifemaker I know would do).
If he will not, then you know that he isn't the fellow for your next knife order.

In hate to use a trite saying, but often when looking at a lower price, you get what you pay for.

LOL....Yeah, but they also say you never know until you try......
Thing is I never would have even looked twice except for the double blade grind and the handle shape with built in guard. Its about the closest to the Horace Kepharts Colclesser Bros double convex blade available, and he made 5 of them. I figured it was worth a shot.

Still waiting to hear back from him.

 

[Arathol]

You don't have to name the maker if you don't want to but please tell us where he is from and anything you know about him, his equipment/methods, and his experience. Is he a well known maker, or just someone selling online.

Some additional info from the maker on the process used to make the knife

The Kephart knife is made of 1084 steel, similar to the steel used in Kephart's time. It is heat treated in an electronically controlled electric furnace. Hardening temperature is 1075 F. It is then quenched in Parks AAA quenching oil.

After cleanup, it is normalized with two two hour sessions in a 400 degree oven. This reduces brittleness. This results in a sharp, tough blade. The result is a Rockwell hardness between 55 and 60. It takes and holds a sharp edge, yet sharpens easily. This is a valuable feature when camping or hunting.

 

[Robert Erickson]

If he's "hardening" it at 1075 degrees the RC is probably 40. You harden 1084 at 1460 or so.

 

[Alex Topfer]

Wait, 1075 is like 580c. WTF? That's like a black heat. Is his furnace calibrated?

 

[Arathol]

Yeah I thought that was a bit odd, I am trying to confirm that is the actual temp he uses. Still waiting for this guy to say he will stand behind his work......

 

[Seedy Lot]

Also a hardness range of 55-60 is pretty ridiculous.

 

[Arathol]

Also a hardness range of 55-60 is pretty ridiculous.

Yep, thats about it, but thats what he is saying..
This guy is looking more and more shady every time he answers.

He says the billet is from New Jersey Steel Baron. Don't know anything about them...

 

[SwissHeritageCo]

Yep, thats about it, but thats what he is saying..
This guy is looking more and more shady every time he answers.

He says the billet is from New Jersey Steel Baron. Don't know anything about them...

NJSB are pretty solid. Seems like the maker himself is the unknown quantity.