Cracks while forging 5168

A.McPherson

A.McPherson

Knifemaker / Craftsman / Service Provider
Joined
Jan 27, 2012
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Hey all you forging gurus, I was forging some 5168 this morning and I got some cracks along the spine while trying to correct the tip angle.

The cracks happened while the steel was pretty cool, it had just cooled into the black heat, but I wasn't hitting very hard. I also do know that I over heated it a bit a couple times.

I also accidentally melted some brass in this forge, but I scooped it out... Could that be part of the problem?

Here's some pics.

https://imgur.com/a/qqtK3uR

The same thing happened to some W2 I was forging, but I wasn't forging that cold...

https://imgur.com/a/NEwbMcI

Y'all think that the low heat was the problem or is there something I'm missing here?
 
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Propane forge. I don't think the over hearing happened before I started forging, but it definitely did happen.

I was forging a wrought iron guard for a bowie at the same time and it got left in a bit long.

It wasn't sparkling or anything when I took it out of the forge, but it was in the high yellow range...
 
You are correct. The melted brass and forging too cold are both a problem. I would also guess that you are forging too hot also.

Is 5168 a real thing or is it supposed to be 5160H?

Hoss
 
The 5168 thing may go back to me. I have some ABS papers from the late 1980's on where to buy supplies. One place back then was "Stanley spring works" in Harrisburg Pennsylvania. On the paper I had written 5168 for the steel Stanley spring works sold. So I told others that my forged knives were made of 5168 steel.
A. McPherson has visited my shop several times and I may have given him a piece of what I called 5168 steel. That's probably why he called it 5168.
Later, I wondered if there even was a 5168 steel. I spoke with Jay Hendrickson who taught the ABS class where the supplies paper came from. He said it was 5160 steel not 5168 steel.
So, maybe that's where the 5168 term came from. I have no idea why I wrote 5168 on the supplies paper.
Maybe someone can add some clarification.
 
Tom Lewis said:
The 5168 thing may go back to me. I have some ABS papers from the late 1980's on where to buy supplies. One place back then was "Stanley spring works" in Harrisburg Pennsylvania. On the paper I had written 5168 for the steel Stanley spring works sold. So I told others that my forged knives were made of 5168 steel.
A. McPherson has visited my shop several times and I may have given him a piece of what I called 5168 steel. That's probably why he called it 5168.
Later, I wondered if there even was a 5168 steel. I spoke with Jay Hendrickson who taught the ABS class where the supplies paper came from. He said it was 5160 steel not 5168 steel.
So, maybe that's where the 5168 term came from. I have no idea why I wrote 5168 on the supplies paper.
Maybe someone can add some clarification.
Click to expand...

Don't worry, I do things all the time and wonder why I did them to begin with :p
 
Tom Lewis said:
The 5168 thing may go back to me. I have some ABS papers from the late 1980's on where to buy supplies. One place back then was "Stanley spring works" in Harrisburg Pennsylvania. On the paper I had written 5168 for the steel Stanley spring works sold. So I told others that my forged knives were made of 5168 steel.
A. McPherson has visited my shop several times and I may have given him a piece of what I called 5168 steel. That's probably why he called it 5168.
Later, I wondered if there even was a 5168 steel. I spoke with Jay Hendrickson who taught the ABS class where the supplies paper came from. He said it was 5160 steel not 5168 steel.
So, maybe that's where the 5168 term came from. I have no idea why I wrote 5168 on the supplies paper.
Maybe someone can add some clarification.
Click to expand...
That’s very interesting. I always assumed it was some southern boy saying 5160H and the person listening heard 5168.

Thanks for clearing that up.

Hoss
 
It is 5160. There is a video somewhere where a well known person repeatedly says 5108. A later version he specifically says it is 5160H, not 5168. He said he wrote it down when he was told the steel type and wrote what he heard.
5160H is 5160 which has undergone HT for the spring industry. If you used it for making a knife, the HT would be undone and redone in your final HT.
 
DevinT said:
You are correct. The melted brass and forging too cold are both a problem. I would also guess that you are forging too hot also.
Click to expand...
Out of curiosity. Does residual brass in the forge cause cracking or does it cause other problems (besides the potential for zinc fumes).
 
Cool, thanks for all the feedback!
Tom, you're right on the money, that's the piece you have me way back!

I'm wondering the same thing as Ben. Should I re-line my forge? To be honest I have been considering throwing this one out, it's a bit too small...
 
Can anyone explain what would be happening metallurgically with the brass and steel?
I would have thought the zinc would have burnt off, and the copper atoms being too large to readily diffuse into the steel
 
The eutectic temperature point of copper and iron is 1435°F/780°C.
Coper will form a eutectic alloy with the steel and change the melting point and other properties if heated in contact ) or mixed molten) above that temperature. Time and temperature are the controlling factors. To form a eutectic alloy in making mokume, it may take 10 hours at the lower end of the temperature curve. I honestly don't know how fast the alloy would form at forging temps, but it would probably be not a long time.
If forging something that is in direct contact with a reasonable amount of copper, for a long enough period of time, this would happen and the steel would be damaged to some degree. Cracking would be one of those possibilities.
However, the amount of diffused copper in vapors would be insignificant. It is actual metal-to-metal contact that causes a eutectic alloy to form. If you are doing something with copper/brass/zinc in the forge, just make sure it is all removed before forging blades. You can melt copper in a forge at 1981°F, but you won't vaporize it unless your forge runs at 4700°F. If the copper is in the direct flame of the burner, it might toss a few atoms into te atmosphere, but the actual metal mass will remain a liquid until it cools below 1900°.

I have read wives tales of someone tossing a penny into a forge to spite an enemy or ruin a knife/sword, and supposedly rendering their forge and item useless forever. this is balderdash (excuse my strong language).

Think about it, how many of us have made or used both mokume and cu-mai ... how dd that not destroy the steel in the cu-mai blade and ruin your forge and future blades????

Like many folk tales, it is most likely an attempt to explain a bad forging effort on something mysterious ... besides yourself.
 
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The edges of copper-mascus that I’ve seen have to trimmed quite a bit to get to clean material. The edges are badly cracked or crumbled.

Copper or brass in a forge is not good.

Hoss
 
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