Metallurgy of Steel for Bladesmiths- Dr. Verhoeven

[Mark Reich]

In this thread, I would like to introduce this work of John Verhoeven, as the first subject of study for anyone interested in metallurgy as it applies specifically to anything related to knives.

Mr. Verhoeven's work is generally recognized as the most accurate and digestible writing specifically for knife enthusiasts, but still, without some formal background in metallurgy, it's not easy to digest much of it without discussion.

A search for John Verhoeven's writings will bring up at least four different studies. They encompass basic metallurgy, blade metallurgy and even one study specifically about Sharpening! 

I've tried to study this by myself, but TBH, some of it is beyond my pay grade. I have been able to take some specifics and apply them to my study of 52100, but Mr. Verhoeven's work encompases all aspects of blade steel.

Mr. Jan, I'm particularly interested in what you think of this. I'm pretty sure your background will come into play, as this does begin with atomic structures. From there, some familiarity of metallurgy would surely be helpful.

Everyone, please understand that this is meant to be a long term discussion. If there is enough interest, we will make it a sticky, because I don't expect this to be an everyday topic, but one in which we can casually meander through. If we can manage to do so, I believe it could become a discussion of significance for everyone. 

Since this is mainly a sharpening centered forum, if you would rather jump straight to Verhoeven's study on sharpening, I completely understand. It might help to take this quick overview of basic metallurgy first, but I leave everyone to their own designs, as one thought will surely lead to the next.

The floor is open! Please feel free to post all relevant discussion. 

Thank You!

[Jan]

Mr. Mark, thank you for drawing our attention to the book Steel Metallurgy for the Non-Metallurgist by J. D. Verhoeven. It is nice introduction into steel metallurgy for people with some background in physics or chemistry and hopefully also for knife enthusiasts who are able to overcome some background gaps (vacancies in metallurgical terminology). 
 
The above quoted book is not available for free on the Net, the full cost on Amazon is circa $70. Fortunately prof. Verhoeven granted any private user permission to download and print a copy of an almost identical book entitled:  Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel.

It can be downloaded here http://www.hybridburners.com/documents/verhoeven.pdf
 
I hope this book can help us to catch on to basic ideas of metallurgy even if we have no formal metallurgical education. It is not an easy reading because metallurgy is not an elevator pitch.
 
Jan

[wadebevan]

Thanks Jan!

[Mark Reich]

Thanks Jan! 

I couldn't figure out why I couldn't  download that book, as I have the one you linked to. I thought all of Dr Verhoeven's work was for public consumption.

I hope we find some interest for this topic. I need to read it again, and again.... and again........ 

It sure is great to have you guys here!

[wadebevan]

There is interest here!
Already about 25 pages in... sure wish my chemistry grades were better
The book is very well written, great analogies.

[Mark Reich]

I'm on board. Whenever you want to talk about phase diagrams of steel, I'm ready.

[Jan]

Mr. Mark, I have finished reading the first third of the book by prof.  Verhoeven and can confirm that it is really well written introduction to practical metallurgy. Huts off to the author!
 
The book content is well digestible for me but the huge amount of facts about steels forces me to read it again to memorise the important items.  
 
I think that it may be too ambitious to open now a general discussion concerning phase diagrams of steels, but what we can do is to focus our attention to much narrower field, e.g. behaviour of "your" extra clean 52100 chrome steel.

I think it may be of general interest to read how the metallurgical education can help to heat treat this steel and maximize its performance.

What atmosphere do you plan for your heat treatment? Do you plan some flame hardening or induction hardening of the blade? How do you plan to reduce the surface oxidation of the blade?
 
Jan

[Mark Reich]

Hi Mr. Jan, I would be happy to discuss whatever is most interesting to you.  

My kilns are atmospheric, and I haven't seen anything about trying to run inert gas through them. I know heat treat companies have that capacity, but the S35VN and M4 blades I've gotten back still have a tough coat scale. Certainly not like I get in my kilns, but you still have to deal with it.

I do flame harden the edge of the blade, then totally finish it to 600 grit before I etch the blade to bring out the differential HT.

The way I HT is kind of a long story. That's something most bladesmiths end up figuring out for themselves. I've broken most of a 5 gallon bucket full of knives, and I continue to test blades to destruction. Virtually every blade I reject donates its body to science. It's fun.

There are a few ways I deal with surface oxidation. I can leave the forge finish, or sandblast, or grind it, or dissolve the scale with vinegar.

[Jan]

Mr. Mark, thanks for your comment concerning your blade steel HT.
 
Your notes started my memories on one high-temperature metallurgical experiment during my studies several decades ago. We were tasked to produce very clean Si or Ge ingot for electronic components using the method of zone-refining. This method utilises the fact that most impurities have higher solubility in the melt than in the solid metal. An impure bar was passed slowly through a hot zone which melted small section of the bar. The impurities built up in the melt and were "escaping" before the solidification front. After several passes high levels of cleanliness were reached.

       

[me2]

I'm on board. Whenever you want to talk about phase diagrams of steel, I'm ready.

Ok.  I'm in.  (Just saw this thread).