Notifications
Clear all

My quest to make crucible steel

18 Posts
3 Users
0 Reactions
598 Views
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Call it wootz, Pulat, Bulat, or whatever, over the past several months I have embarked on a journey in an attempt to recreate that fabled steel. First, I had to build the crucible furnace. Here is a pic during a melt operation.

 

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 19/12/2023 10:13 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

I have made six "pucks" or "ingots" all in the 1 kg range using a small variety of carbide forming alloying elements, or just adding carbon to pure iron. They look like this.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 19/12/2023 10:18 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Forging these out has been quite the steep learning curve. The carbon content is somewhere in the 1.5% to 2.0% range making them rather fragile. The first two attempts were abject failures as the pucks blew apart almost immediately.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 19/12/2023 10:21 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Last week I put a couple of pucks through a series of roasting cycles and tried again over the weekend.

Here is a link to the latest process.

https://imgur.com/a/gmFQ4qf

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 19/12/2023 10:25 pm
Mark Lambert
Posts: 17
Eminent Member Apprentice Bladesmith
 

i've been watching you at it on facebook and have enjoyed seeing your work on it. Eventually i hope to give it, or bloom steel a go. 

 
Posted : 20/12/2023 2:46 pm
Karl B Andersen
Posts: 95
Journeyman Bladesmith Forum Moderator
 

Those are good looking pucks. You have a facebook page? I can't find it by your name search.

 
Posted : 21/12/2023 8:27 am
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

I have two FB pages

Dos Gatos Forge

J.States Bladesmith

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 21/12/2023 11:08 am
Karl B Andersen
Posts: 95
Journeyman Bladesmith Forum Moderator
 

Got it. We're already friends. I was searching your full name.

 
Posted : 22/12/2023 9:21 am
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

I also have an IG account under J.States_Bladesmith
For anyone intersted in following, I use social media primarily for business and knifemaking. You will not see any socio/political commentary from me. I'm not there to push an agenda, just stuff that my wife and I make in our shop and events happening in our life. Social media fosters too much anger and I try to avoid it.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 22/12/2023 12:14 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

I cut the bar open to see the interior, and set about forging the bar into a blade. I found out the hard way that this steel doesn't really like too much forging to shape. I had to cut off several inches during the process as the material started cracking. So, I decided to forge a rough shape and bevels. I ground the profile shape after normalizing treatments.

https://imgur.com/a/rnWIxkz

 

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 25/12/2023 6:36 pm
Mark Lambert
Posts: 17
Eminent Member Apprentice Bladesmith
 

I know you've been trying different recipes in regards to iron, carbon, etc. ; however, do you think the brittleness of the steel is attributed to the high level of carbon content? Or possibly the presence of a fair amount of phosphorous?

 

I'm no expert in the realm of metallurgy, and i'm trying to at least learn a little about crucible steel through your work. link for explanation on why i thought of those two reasons on why it is crumbling so easily for you.

 
Posted : 25/12/2023 7:13 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Posted by: Mark Lambert

however, do you think the brittleness of the steel is attributed to the high level of carbon content? Or possibly the presence of a fair amount of phosphorous?

There's is a lot at play here, but I do not think any of it relates to P content because I am not adding anything to the melt that would contribute P. All these pucks are very high carbon, i.e. 1.3% and higher. Classic Wootz is anywhere from 1.3% -1.8% C.
I think I have a problem calculating my ending carbon content and am getting much higher than I'd like. My target is 1.5%, but I relly don't have a good understanding of a couple of things:
1. How much pure carbon is available from my charcoal by mass ratio
2. How much of that burns off in the melt
3. How much of what is left can be absorbed by the iron
4. How much material is lost in the melt (iron included)

I had erroneously assumed that the mass of iron in, would equal the mass of iron out. Any resulting change in mass from charge to ingot would be the net carbon gain. Then I had a couple of pucks come out weighing less than the sum of ingredients in the crucible and I have to rethink this.
Ah, the joys of experimentation!

Another part of the process I have to get under control is the ingot roast time and temperature. As it turns out, the puck is not homogenous material. Portions of it have higher concentrations of alloying elements (including carbon) than other portions. So, you have to roast it above ACM to achieve a more hogenous composition. This is another work in process to figure out and it is also dependent upon what went into the crucible.

So, I'm taking a lot of notes.

Summary: The brittleness of the first pucks is largely do to poor pre-forging preparation and very high carbon content, but not high enough to lower the melting point by any significant measure. I have some 4.5% cast iron and it literally melts to the consistancy of gelato at around 2000F.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 26/12/2023 9:19 pm
Mark Lambert
Posts: 17
Eminent Member Apprentice Bladesmith
 

By roasting, do you mean performing a homogenization heat treatment

 

It's just a thought, and i'm no genious so take it as a grain of salt. Since we know the iron is definitely not evaporating, maybe you are seeing a loss at the atomic level, and there are other atoms bonded with your iron. When it reaches a molten state, they are expelled in the form of gas, causing a net loss. I figure the only true way to tell is to get the chemistry set out and take a look at the chemical composition of your ingredients, and or use a spectrometer?

 
Posted : 27/12/2023 12:58 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Posted by: Mark Lambert

By roasting, do you mean performing a homogenization heat treatment

Basically yes, but it's more of a "diffusion" heat treatment, where you are attempting to diffuse the alloys throughout the steel.Pendray talks about the Wootz makers (and himself) "roasting" the ingots at high heat in a variety of fashions. Sometimes they were stacked up inside eathen ovens filled with charcoal powered by blowers, other times were small boxes filled with anti-oxidants, yadayadayada. It doesn't help that most of the writen stuff by Pendray and others doesn't use actual temperatures. They just describe heat by color and no matter what the process involved, "bright red" seems to be the hottest they ever use (even for forge welding). It's almost like they all were orange/yellow colorblind.

Without getting into the whole chemistry involved, each puck is pretty close to a unique steel and no two pucks behave exactly like each other, unless they share the same composition. Hence the experimental nature of this endeavor. Every maker I am fortunate enough to woo into a discussion of their process seems to have a process that is specific to their favorite formula.

Yes, I could send these pucks out for spectral analysis, and get an assay of the composition, but that would rquire some diffusion heating first. My objective at this point is to simply develop a couple of different "recipes" that I can forge into bars or blades and produce good patterning, and do it reliably. Only then will I contemplate forging a couple of bars and sending them out for analysis.

At some point, I hope to have 2 or 3 different recipes that I know how to replicate, and get good patterning out of. Then I will name them and get an assay to show prospective buyers.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 27/12/2023 10:11 pm
Joshua C States
Posts: 316
Reputable Member Journeyman Bladesmith (5yr)
Topic starter
 

Just to clarify the effect that even minor chemistry changes cause, there wer tow pucks in the post above from 12/19. They had different alloying elements, but the same amounts of iron & charcoal in the melt. They went through identical roasts simultaneously, and were also forged simultaneously using the same forge and temperature.I forged them in the press, using the exact same compression levels for each forging operation.

I showed the one that behaved well and I managed to forge into a usable bar. The other one didn't make it very far as evidenced by the attached photo.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 27/12/2023 10:22 pm
Page 1 / 2
Share: