Reference Books and pages

Mike Blue

Member
  1. Verhoeven, John. Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel.
  2. Verhoeven, John. Steel metallurgy for the Non Metallurgist.
One is available online in pdf form. The other is available in print. If you heat treat metals, you should have these. Pay for what you can. John has earned that right to help us all.

3. Thomas, Larrin. http://knifesteelnerds.com

Larrin is the son of Devin Thomas. A metallurgist who is collating information specifically for blade makers. He will be one of the knowledge sources for the generation that is coming. I think he accepts Patreon sponsors. His stuff is readable (he knows his audience). He kills myths.
 

Victor Creazzi

King of Bondo
Dr. Larrin Thomas just came out with a new book entitled 'Knife Engineering: Steel, Heat Treating, and Geometry'

Looks great! I've been reading his blog 'knife steel nerds' for a while and had hoped that he would put the info into an organized book.
I ordered it the day I saw that it was available. I should get it Aug 1.
 

Victor Creazzi

King of Bondo
Got my copy! I'm excited to get started reading this book. Leafing through it I see many things that I'm very interested in, but I really want to read this from page one, the first time. I like the fact that the first chapter is on steel and knife properties, the mechanical properties in other words. The whole book looks to be very well organized. More later.
 

RezDog

Member
I had to order the book from Amazon.com because it was far cheaper than ordering it from Amazon.ca. Amazon Canada has over the top ridiculous pricing on delivery to my address, it was $54 just for the delivery. After dollars exchange and shipping from Amazon USA, it was marginally more than the cost of shipping from Amazon Canada. Here’s the stranger bit, it will likely get shipped from Amazon Canada.
However, the most important part of this post is, I have another great reference book enroute.
i am quite happy for this thread.
 

Bruno

Administrator
Staff member
So far i am liking the book. Looking forward to the part about alloying and carbides.
 

Victor Creazzi

King of Bondo
So far i am liking the book. Looking forward to the part about alloying and carbides.
Same here. If I have one complaint it would be that it is a little too knife centric. I find myself translating into general steel properties. I'm in chapter 8 of 29.
 

Victor Creazzi

King of Bondo
Wow! I really got a lot out of the chapter on normalizing and grain refinement.

I see a discussion on sub critical annealing coming up in the next chapter too.
 

Mike Blue

Member
For a long time Victor, all the metallurgical books focused on block-like shapes and how steels evidenced their internal structures and characteristics. The main audience for such work were industrial giants. If it wasn't for people like Alfred Pendray and Howard Clark testing materials in sharp angular shapes and discovering performance differences, we would not have metallurgists such as Larrin to write this stuff in books. Larrin's provenance is from Devin Thomas who is the stain resistant steel specialist of the knife world from 30 years ago. All of them could understand and express what they knew, but were often distracted by a hot fire and the anvil's ring. All of them have been told to write a book but it hasn't happened. We're lucky to have Larrin.

I've learned a few things from Larrin especially in the areas where he's taken blade shapes through heat treatment and then on to the cutting tests. This is where grain refinement and setting up the heat treatment for performance are shown to have the largest effects on what the end user wants and where we try to push our blades to make worthy products. Your concern about his book being knife centric is accepted, by me at least. Even as I say, "It's about time."

My copy should arrive today. I look forward to it. His website is chock full of interesting bits, especially the graphic content. He has not answered all my questions, but I am patient and know that he has a real job too.
 

Victor Creazzi

King of Bondo
I guess part of my knife centric comment is similar to the dust up that happened on one of the kitchen knife sites. Larrin had posted a blog that had the CATRA test results for a number of knife steels. Some in the kitchen knife crowd argued that the CATRA test was a poor choice for evaluating steel for kitchen knife steels because the test material contains a specified amount of abrasive material, and kitchen knives are seldom cutting anything with abrasive content. It was pointed out that the testing was not done for evaluating kitchen knife steels exclusively and was for general knife steels. The whole thing was a bit silly to me, as it was obvious that certain aspects of the tests had to be evaluated on how they related to any specific use.

I still found the CATRA test results interesting, but I'm not sure how they relate to using steels for razors because of the same arguments. I am however smart enough to take those factors into consideration myself without complaining that the tests utilized don't fit my specific application.
 

Mike Blue

Member
That's true to knives history. There have been arguments for generations it seems. The first big dust up I recall was whether forged knives were better than stock removal. In the main due to the manipulation of the grain to form something closer to the profile. The argument was based on some data from the Cubes of Industry that influenced knowledge at the time. It all fell apart 30 years later when the clarity of heat treatment and grain refinement came into its own and showed that it didn't make any difference after a good heat treat (including normalizing and grain manipulation.) There are some sore losers leftover from that debate.

The Brits with CATRA, and in the US mainly Spyderco pushed the knowledge of cutting angles and heat treatment together. Spyderco had a standing offer to take a Mule (specialized tang basically, with Your edge and heat treatment) and run it on the CATRA machine. Only you and Spyderco would know the results. In this way Sal was able to collect information about what edge angle and steel/HT together were the best of the day. That program is still open to anyone who wants to know how their stuff stacks up.

I work in medicine and have stood in for surgeries. Those medical grade scalpels edges don't even last halfway through a cut sometimes (think big broad belly). They are the best stainless stuff that the razor/scalpel makers metallurgical engineers can come up with. Probably balanced against cheap as they are one-use blades. Like the Kitchen Crowd, these blades seldom cut abrasive things. But they dull quickly. The chefs I know are hard on their knives and may have their blades professionally sharpened once a week because they like sharp knives.

Segue: D. T. Suzuki wrote a book called "Zen and the Art of Japanese Culture." I recall a story in there about a butcher. It's an enrichment story if you like that sort of thing.

Cutting flesh or fruits and veggies and dull blades is fairly simple and can't be tested by CATRA. A better environment is acid or alkaline as these will etch the edge into something less than perfection. No one has worked on a steel critieria for chemical or biological environmental resistance yet. I am interested in seeing how H-1 will perform since it's advertising is complete resistance to salt water erosion. It's not the greatest for edge deformation but it does hone quickly to sharp again even on leather. I know Larrin was discussing modifying his CATRA machine for other materials. Somehow the idea of a multi-thousand dollar testing machine covered in tomato juice bothers me. Maybe someday.

The reality of steels in knives is that when we figure out how to test better, some group coughs in the back of the audience and suggests an exception. We have to be open minded and add their data.

Because of Spyderco's experience with CATRA, especially Larrin's graphic work, it's a good place to begin evaluating which steels will be good points to begin making razors. As to abrasion resistance and toughness, I use the ancient criteria that beard hair is about the equivalent of copper wire of the same diameter. The most recent public discussion of razors implies that "beard hair is soft but still dulls razors." They don't discuss the scale or how that was tested. Any of you want to make some mules? I do not doubt before the SR project goes very far, that Spyderco will have made some in various steels and tested them. I don't know if I will get to see the results. What would be useful are different hollow grades as those have the least amount of testing available.

Larrin has not done testing on any blades in Bainite. Sal is excited to add that variable to their line for more than razor reasons and I agree with him. Of all the steels to choose from, simple steels like O-1 and 52100 rise to the top of the list because of the bainite potential. Some like CPM154 do as well and a few others. Then stain resistance enters the decision tree. Vanax has also been discussed. I have my own research to do too.
 

Mike Blue

Member
....I still found the CATRA test results interesting, but I'm not sure how they relate to using steels for razors because of the same arguments. I am however smart enough to take those factors into consideration myself without complaining that the tests utilized don't fit my specific application.
This is literally all we had "back in the day." Industrial knowledge and a bunch of good guesses went to work and trial and error came next. This truly shook the tree of knifemaking and rapidly sorted out the heat treatment effects to all our benefit. The wave is coming for razors Victor. You'll be one of the first, then one of the oldest. LOL.
 

Bruno

Administrator
Staff member
Any of you want to make some mules? I do not doubt before the SR project goes very far, that Spyderco will have made some in various steels and tested them.
I would love the opportunity to see how wootz holds up after my heat treatment. Is there documentation as to shape and dimensions?
 

Bruno

Administrator
Staff member
I recently saw a couple of REALLY nice flowing wootz patterns and got this link to explain more about the smelting particulars.

I just got instructions from Achim on dimensions and a burner for the smelting furnace. I'll be building one, hopefully not too long from now.
 

Mike Blue

Member
I have to digest that article Bruno. I briefly scanned it and it kind of feels like a graduate student in archeology thinking he knows something.

Achim is a good source. I'll contact Spyderco to see what their requirements are. I'd bet he has data on Pendray wootz already.

When the CATRA machine was first developed testing occurred. Think 1980's. Howard contributed some of the test-mules for Verhoeven and Pendray. The two steels that outperformed all the rest were 52100 and wootz. 52100 was the best cutting steel in the hardened state. Wootz outperformed 52100 in the unhardened state. Think about that result Bruno.

Here is a true Rabbit Hole to fall down. http://www.cliffstamp.com/knives/forum/read.php?5,2040 Cliff can be miserable to debate. He knows what he knows and is difficult to get to consider alternatives. He will make you think about things.

But, in this thread he makes a good criticism of the CATRA methods as far as a single important limitation. Sharpness. It is possible to get an edge on a low to medium steel to outperform a better steel (modern hot selling unobtanium etc) on a CATRA machine simply by sharpening the edge thinner. This may be an area of razor performance that should be added to the data pool. The information as a preliminary point, should be available in hollow ground knife edges if they were submitted. Spyderco will not likely release that information due to their policies. Larrin might investigate something like this question if we can catch his interest.

Cliff brings up something in that thread that Larrin's book reminded me of about steel choices. Most stainless steels have a double bump curve for hardness post quenching that occurs in the tempering cycle. A good many knives were heat treated to take advantage of that second hardness increase during tempering. But at or near that second point the SS also loses corrosion resistance and toughness despite the increased hardness. It's not an advantage with those losses.
 

Bruno

Administrator
Staff member
I haven't read the article in full yet. However the one thing I thought really interesting to try is the layering of glass not on top but in the middle. Without having studied or tested it, it's purely conjecture on my part. With the glass in the middle, it is basically going to melt when it is embedded in molten steel.

Logically, it's going to rise to the top when everything is molten, which means it is going to 'stir' the molten contents which would improve uniformity.
And 'maybe' it would leave traces of carbide forming elements in its wake too, though the latter is purely unsubstantiated thinking.
 

Victor Creazzi

King of Bondo
In the article, the conjecture is that the high carbon iron drips through the charcoal and through the molten glass into the low carbon iron below the glass. Eventually the iron below the glass takes on enough carbon from the 'drippings' to melt also. All the slag, extra charcoal, and light impurities, stay on top of the glass. Very interesting article. Thanks for posting
 

Mike Blue

Member
First critical point noted in the abstract. The archeologists found some slags. They deduced that some sort of steel smelting occurred on that spot or close by. This is where two schools of thought have derived and guided the researches. One school finds a slag and attempts to develop a process that reproduces the slag they found (chemically mechanically whatever...). If they come close to reproducing the slags they have reached their goal.

The second school (in which I am wholly invested, caveat), says, you boys/girls have found a bunch of glass. Where's the iron or steel? And it's much more likely to be steel because making iron in a smelt requires changing the conditions. I'm a blacksmith and I would prefer steel or steelish irons much more than iron alone.

The dominant equation is time at temperature. The author discusses none of that except briefly and does not identify these factors importance to any of the processes.

He has correctly identified a process that produces a 0.8% carbon steel puck. There are multiple waste products that contain iron or carburized iron. This is not as efficient as making steel with 1.4-1.6% Carbon as is done by others. Pretty much everything except those materials that are expected to form slags go into the puck produced.

Bruno. Watch some crucible smelts. Carbon averaging occurs within minutes of reaching the right temperature, like sugar dissolving in tea. The stirring process would not get enough from dripping. It's another process easily seen in the crucible. The glass separates the outside environment from the inside. Stirring occurs from a different process. This suggests to me that the author was not interested in the metalllurgy, or the crucible when hot. He wanted to duplicate a slag, and then assume the steel puck would be right if the glass was right.

Victor. Eventually in this author's case is the key word. Think Time at Temperature. But you are correct, adding carbon to iron lowers the melting temperature. How much time does that take? And if all the light elements such as charcoal are above the glass how do they provide carbon for steeling below the glass?

Bubbles coming up through the glass layer will only bubble the glass. Outgassing is common and desirable. Pendray used to drive Verhoeven nuts buy putting a couple eucalyptus leaves in each crucible where it had a specific purpose.

A reducing atmosphere is highly desirable.

Another graduate student assembling Google facts from the wrong school of thought without getting his hands dirty.
 

Victor Creazzi

King of Bondo
Victor. Eventually in this author's case is the key word. Think Time at Temperature. But you are correct, adding carbon to iron lowers the melting temperature. How much time does that take? And if all the light elements such as charcoal are above the glass how do they provide carbon for steeling below the glass?
My take on it was that the iron above the glass had absorbed enough carbon to become cast iron which melts at a much lower temp than steel. Then the cast iron went into the iron below the glass and gave up some of its carbon to make the steel.

I admit to reading the article pretty quickly and I will go back and read it again, but I thought the description was from a current artisan who was using a process that he had developed independent to the historians, but that matched what they thought would produce the artifacts that they were finding.

I will have to read it again, but not tonight.
 
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