Metallurgy Question.

A

Almightyox

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Jul 29, 2014
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Hey folks. I have been talking to one of my friends about blade making and he brought up a few things about usage of metal in blades. He make mention of a few types of steel such as Chrome-Moly, and Hastelloy. Are these steels that can be used in bladecrafting? What is it about them that makes them good/bad for the task? Any help would be appreciated because I see steel selection and metallurgy to be one of the most confusing parts of blade making. Thanks in advance.

-Ryan
 
Chrome-Moly is not a single grade of steel. It is a group of steels containing Chromium and Molybdenum. Some will male good knives and some will not. Hastalloy is also a group of steels and not a single grade. I'm not aware of any grade of Hastalloy with enough Carbon to make a good knife.
You would be wise to avoid any advice about blade steels unless you know the person to be a knowledgeable knifemaker. There is a lot of false information about which steel type makes the best blade. There is no perfect steel, if there was we would all be using it. Don't get too wrapped up in steel choice. Proper heat treat, working hardness, & geometry are just as important as steel choice.
 
Well said Darrin.

Ryan, you would be wise to consider this man's advice. There is a LOT of poor advice and outright bull in blade making. It's all science. No matter how bright the light of the moon that you forge in, or how pure the virgin blood you quench in or how clean the unicorn urine you sprinkle on your anvil, it's all science. There are some things that are pure art in knifemaking, but heat treating isn't one of them.

No matter how many times you put a knife in the freezer or how many days it takes to heat treat a blade.......
 
As a general rule, I would not consider either Chrome-moly or Hastaloy for knives. Both are made for high toughness...not edge hardness.
 
Thank you Darrin. I did not come here with the notion that what my friend had said was gospel, otherwise I would have purchased metal already and had it shipped to my door without any mention of it on here. I brought it up in a thread because I wanted to ask knowledgeable knifemakers before I made a decision. I know that one grade of metal might work well for what he uses it for, but not work well for a blade. I come to this site to learn, just like the rest of us, and I have no preconceived notion that I have even the slightest clue what I'm talking about on some subjects.

Higher carbon content usually means higher strength and edge retention correct?
Does this mean that high carbon will inherently have the best edge retention?
Does stainless sacrifice edge retention for corrosive resistance and higher tensile strength?
 
Almightyox said:
Higher carbon content usually means higher strength and edge retention correct?
Does this mean that high carbon will inherently have the best edge retention?
Does stainless sacrifice edge retention for corrosive resistance and higher tensile strength?
Click to expand...

Ryan, this is a good and reasoned question. Step one in this forum, if you're truly serious about learning the reasons behind the choices blade smiths make, it's to read the stickies. I know that seems cliche, but in this forum you really really need to. There's a whole new vocabulary you need to learn if you want to really understand the how and why.

The short answer, stainless steels often have higher carbon than non stainless. Stainless steels have chromium added which helps with corrosion resistance. Just as each step in making a knife must be performed as of it is the most important step, each element adds something to the mix and lends certain attributes to the end product.
If you can, search for any posts by Kevin Cashen. Then read and reread them. The man is brilliant.


Read the stickies. All of them. Write down your questions as you go then all them in bunches. It well become increasingly clear as you go along.
 
For the real truth [I'm a metallurgist LOL ] The good starter steels are 5160 and 1080. Both are easy to forge ,easy to heat treat and make a good edge. From there you can go to the more complex steels .Each steel is different and a learning experience.
 
Well I thought I had read through the stickies on this topic but there was one major one I missed. One of them authored by Mr. Cashen mentioned above. After reading it I am starting to understand the difference between Hypo, Hyper, and Eutectoid Steels, and the effect carbon content has on heat treat requirements. From what I understand about Chrome Moly (4130 for example) has a carbon content of only .3%. This would make it poor for blademaking since while the added alloys may give it a high tensile strength, it's low carbon content would give it poor edge retention and hardness (Appr 90 Rockwell B = only about 15 Rockwell C). On the other hand, Chrome Moly like SKS-3 has a carbon content of .9 - 1%, giving it the ability to harden far beyond 4130, much like other Hypereutectoid steels. Is this correct?

Thanks for all the help and patience. I am serious about learning the ins and outs of this trade, I just somehow overlooked the most critical sticky on this topic. I think I just looked through the basic "count" stickies, not the full list. I think I'm catching on a little now though :)
 
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SKS-3 isn't a chrome-moly steel. It is a die steel that has 1% carbon, 1% manganese, 1% chromium, and 1% tungsten. It would work for a knife.

It is not just carbon, but the alloys and how they work together that make a steel good for a knife. Cast iron has 3% carbon...and won't make a knife.
ZDP-189 also has 3% carbon, but it also has 20% chromium and 3% molybdenum. I don't think I ever heard anyone call it a chrome-moly steel, but it would classify as one. This is an extremely hard and wear resistant blade steel. Cowry-X is a similar steel. Both make superb slicers....but the price is insanely high. Last bar of Cowry-X I bought cost $200, and it was only 18" long.

All that is fine, but a simpler and lower alloy steel will also make a great knife. 1080, 5160, or in stainless, CPM-S35VN or AEB-L all make great knives.
 
If you want a good explanation of blade steel,composition, and alloying elements, read this after rereading Kevin Cashen's posts.

http://www.feine-klingen.de/PDFs/verhoeven.pdf

You will find it over your head, but as you gather more information, it will make more sense over time. It took me a year to get a reasonable handle on this, and now at about 2 years, I'm feeling more confident in my metallurgy. I'm still learning as I go.

Mete, Kevin Cashen, Me2, Samurai Stuart, and Stacy consistently provide good metallurgy advice on this forum (Kevin through the stickies. He's not a regular here anymore.)
 
That's weird....a fellow just yesterday asked me about using 4140 in a knife. Better suited to hammers and anvils and gun barrels! ALso......isn't that police code talk? Like crazy lunatic knife makers on the loose? "We have a 4140 in progress near Sturgeon County. Better bring in the Mounties!!!!"
 
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samuraistuart said:
WAAAAYYYY too generous there, Warren. Don't listen to me! I routinely bugger up!
Click to expand...


I disagree. You ask the right questions, and come up with very good answers. I think your HT process on the steels you use regularly make a lot of sense, and you don't mislead people if you don't know an answer. :cool: :thumbup:
 
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