Another great thread Larrin :) These threads of yours have been a great learning experience for many of us. Even after taking two metallurgy course in college I'm still learning a lot. Lately there has been some sideline talk about some of the more exotic alloys they are using in some of these "supersteels" that have come on the knife market in the past 10 years or so especially.
There are elements like cobalt, niobium, and tungsten that have raised a lot of speculation about the future of knife steels in general. Where would be a good place to learn about those I just mentioned as well as other elements they might be considering for blade steel?
Also being that I'm very fond of serrated blades much more than I used to be I'm wondering about a way to test steels that would be ideal for Spyderedges and other serrated blades. Because I've personally found that some of the older and more tough or ductile steels seem to have better performance in SE than they do in PE. Three that stand out as being great Spyderedge blade steels are 440V ( S60V), ATS-55 and the old AUS-8 are some I've had great results with over the years.
Re: Which Steel Has the Best Edge Retention?
Posted: Tue Nov 20, 2018 11:07 am
by vivi
Larrin, thanks for taking the time to compile such informative articles, and for sharing them with us here. Much appreciated.
What I would personally be interested in, is seeing how the numbers change when you apply extremely acute edges to the blades. 5-10 degrees per side.
Re: Which Steel Has the Best Edge Retention?
Posted: Tue Nov 20, 2018 11:38 am
by SF Native
Larrin,
You state in the article that the powder metallurgy process doesn’t have an effect on the edge retention. Correct me if I’m wrong, but I was under the impression that powdered metal
has smaller grain and more uniform distribution. This means you have a tougher and more predictable behavior in the steel. That being the case, the heat treat can be designed for a higher hardness (ie higher edge retention) and still stay in an acceptable level of ductility. So, not a direct effect, but an indirect one.
Also, any idea how nitrogen based steels like bd1n would figure in the formula?
There are elements like cobalt, niobium, and tungsten that have raised a lot of speculation about the future of knife steels in general. Where would be a good place to learn about those I just mentioned as well as other elements they might be considering for blade steel?
Also being that I'm very fond of serrated blades much more than I used to be I'm wondering about a way to test steels that would be ideal for Spyderedges and other serrated blades. Because I've personally found that some of the older and more tough or ductile steels seem to have better performance in SE than they do in PE. Three that stand out as being great Spyderedge blade steels are 440V ( S60V), ATS-55 and the old AUS-8 are some I've had great results with over the years.
I don't have any information to suggest that anything other than wear resistance controls edge retention in the CATRA, serrated or not. If I ever obtain such information I will let you know.
What I would personally be interested in, is seeing how the numbers change when you apply extremely acute edges to the blades. 5-10 degrees per side.
That could be a fun study. Presumably there is some lower limit even for CATRA. Chipping or edge rolling is probably more likely the limiting factor though.
Also, any idea how nitrogen based steels like bd1n would figure in the formula?
Cronidur 30 and Vanax 35 are in the chart and there are coefficients for nitrides in the regression.
BD1N is not a nitrogen-based steel, however, it has a small nitrogen addition. It forms primarily chromium carbides; it has an amount somewhere between AEB-L and 440A but there is no published amount that I have found. https://knifesteelnerds.com/2018/09/17/ ... fe-steels/
Re: Which Steel Has the Best Edge Retention?
Posted: Thu Aug 15, 2019 12:09 pm
by Deadboxhero
Here is a follow up discussion about this article with Larrin.
We go through the article and talk about it in more detail.
Topics include:
What is CATRA?
Carbides?
Same steel but PM vs Non PM counterpart?
How does the regression formula work for Predicting CATRA?
Here is a follow up discussion about this article with Larrin.
.........
Heck yea, I'm gonna watch this when I get home.
Re: Which Steel Has the Best Edge Retention?
Posted: Thu Aug 15, 2019 6:24 pm
by Larrin
Great discussion with Shawn
Re: Which Steel Has the Best Edge Retention?
Posted: Fri Aug 16, 2019 7:30 pm
by The Meat man
Great stuff Shawn and Larrin! I hope you guys do more talks like that.
Re: Which Steel Has the Best Edge Retention?
Posted: Fri Aug 16, 2019 8:07 pm
by Baron Mind
Yes these conversations between BBB and Larrin are fantastic. Larrin providing the rock solid scientific answers to age old questions and BBB leading the discussion and making the information more relatable when necessary. It's refreshing to see something presented that's not just another person's opinion, but well researched, and tested facts about knives.
Re: Which Steel Has the Best Edge Retention?
Posted: Fri Aug 16, 2019 9:59 pm
by Deadboxhero
Thanks guys, yea Larrin is legit, smartest guy I know. He is like the brain bug from starship troopers.
I love talking about Metallurgy with him.
One of the problems is that we could go on for hours and hours on a single section, so we try to keep it flowing.
Look forward to having more discussions, I feel that it gets to a certain point with information that the only way to help break it down is to have a conversation about it.
It is my hope that more of this complex stuff will be more common knowledge to folks so that the community can grow.
Thanks guys, yea Larrin is legit, smartest guy I know. He is like the brain bug from starship troopers.
I love talking about Metallurgy with him.
One of the problems is that we could go on for hours and hours on a single section, so we try to keep it flowing.
Look forward to having more discussions, I feel that it gets to a certain point with information that the only way to help break it down is to have a conversation about it.
It is my hope that more of this complex stuff will be more common knowledge to folks so that the community can grow.
Shawn,
I didn't get to watch the video(s), so if this was discussed within, you'll have to excuse me.
How is edge retention affected by corrosion - or if I were to generalize, how is edge retention affected by chemical damage (as opposed to mechanical damage, like deformation, chipping, wear, etc.)?
Thanks guys, yea Larrin is legit, smartest guy I know. He is like the brain bug from starship troopers.
I love talking about Metallurgy with him.
One of the problems is that we could go on for hours and hours on a single section, so we try to keep it flowing.
Look forward to having more discussions, I feel that it gets to a certain point with information that the only way to help break it down is to have a conversation about it.
It is my hope that more of this complex stuff will be more common knowledge to folks so that the community can grow.
Shawn,
I didn't get to watch the video(s), so if this was discussed within, you'll have to excuse me.
How is edge retention affected by corrosion - or if I were to generalize, how is edge retention affected by chemical damage (as opposed to mechanical damage, like deformation, chipping, wear, etc.)?
Thank you.
That was an early article Larrin did with a sharpeness tester and acids to test if the edge losses sharpeness.
It's pretty straight forward, a sharp, non-stainless edge may corriode more readily and lose sharpeness.
In reality, it's a red herring if your looking for reasons why your EDC knife is going dull.
Like they say, when you hear hoof beats, think horses not zebras.
There is a plethora of other factors that are more pertinent to edge holding in reality unless your specializing your use in a extreme environment or specialized for cutting highly caustic materials.
Thanks guys, yea Larrin is legit, smartest guy I know. He is like the brain bug from starship troopers.
I love talking about Metallurgy with him.
One of the problems is that we could go on for hours and hours on a single section, so we try to keep it flowing.
Look forward to having more discussions, I feel that it gets to a certain point with information that the only way to help break it down is to have a conversation about it.
It is my hope that more of this complex stuff will be more common knowledge to folks so that the community can grow.
Shawn,
I didn't get to watch the video(s), so if this was discussed within, you'll have to excuse me.
How is edge retention affected by corrosion - or if I were to generalize, how is edge retention affected by chemical damage (as opposed to mechanical damage, like deformation, chipping, wear, etc.)?
Thank you.
That was an early article Larrin did with a sharpeness tester and acids to test if the edge losses sharpeness.
It's pretty straight forward, a sharp, non-stainless edge may corriode more readily and lose sharpeness.
In reality, it's a red herring if your looking for reasons why your EDC knife is going dull.
Like they say, when you hear hoof beats, think horses not zebras.
There is a plethora of other factors that are more pertinent to edge holding in reality unless your specializing your use in a extreme environment or specialized for cutting highly caustic materials.
Well, even day to day corrosive stuff (citrus, tomatoes, etc) could potentially affect a blade. It doesn't have to be high strength acid.
I'll check out the article. Thank you.
Re: Which Steel Has the Best Edge Retention?
Posted: Mon Aug 19, 2019 8:44 pm
by Pelagic
Very good article. Written intellectually and logically, yet in a simple way. Thanks.
Thanks guys, yea Larrin is legit, smartest guy I know. He is like the brain bug from starship troopers.
I love talking about Metallurgy with him.
One of the problems is that we could go on for hours and hours on a single section, so we try to keep it flowing.
Look forward to having more discussions, I feel that it gets to a certain point with information that the only way to help break it down is to have a conversation about it.
It is my hope that more of this complex stuff will be more common knowledge to folks so that the community can grow.
Shawn,
I didn't get to watch the video(s), so if this was discussed within, you'll have to excuse me.
How is edge retention affected by corrosion - or if I were to generalize, how is edge retention affected by chemical damage (as opposed to mechanical damage, like deformation, chipping, wear, etc.)?
Thank you.
That was an early article Larrin did with a sharpeness tester and acids to test if the edge losses sharpeness.
It's pretty straight forward, a sharp, non-stainless edge may corriode more readily and lose sharpeness.
In reality, it's a red herring if your looking for reasons why your EDC knife is going dull.
Like they say, when you hear hoof beats, think horses not zebras.
There is a plethora of other factors that are more pertinent to edge holding in reality unless your specializing your use in a extreme environment or specialized for cutting highly caustic materials.
Well, even day to day corrosive stuff (citrus, tomatoes, etc) could potentially affect a blade. It doesn't have to be high strength acid.
I'll check out the article. Thank you.
Even day to day citrus and tomatoes,
its not going to make something like 420j2 outcut k390.
That was my point.