Why there is Cobalt in VG-10

[Larrin]

One of the fun things about writing steel metallurgy articles is that I can find answers to questions that I have always wondered. Is anyone else interested in the same questions? Who knows? Cobalt is not a very common element in knife steels. Why would it be in VG-10?

http://knifesteelnerds.com/2018/05/14/w ... -in-vg-10/

[Larrin]

My post was approved! I was going to mention that I have carried a Spyderco Schempp small Persian in VG-10 for several years.

[sal]

Hi Larrin,

Great info. Great site. Joined.

sal

[Larrin]

Hi Larrin,

Great info. Great site. Joined.

sal

Thanks Sal!

[sal]

Hi Larrin,

I would submit that sometimes "known" facts don't always tell the whole story. Eg: Moly was added to Crucible's 154 to stop high temperature creep in Boeing's jet fins (before moving to Titan) and the steel became a knife makers favorite for a long time. ATS-34 was Hitachi's version.

sal

[Sharp Guy]

Looks interesting! I subscribed. I'll check it out more thoroughly later...

[Larrin]

Hi Larrin,

I would submit that sometimes "known" facts don't always tell the whole story. Eg: Moly was added to Crucible's 154 to stop high temperature creep in Boeing's jet fins (before moving to Titan) and the steel became a knife makers favorite for a long time. ATS-34 was Hitachi's version.

sal

Coincidentally I am working on an article about 154CM next, including its development and properties. Molybdenum was indeed added for high temperature applications with 154CM but Crucible later used a 14Cr-Mo basis with steels such as S30V and S110V because of their combination of corrosion resistance and hardness, not for hot hardness. In this article on VG-10 I attempted to differentiate between what cobalt "does" to a steel and "why" Takefu added it. Sometimes it is not known why certain elements were added, it could even be for an "incorrect" reason.

[Eli Chaps]

Very cool. Thank you for sharing and for hosting the site!

I work with metals and love the field but steels are like a mysterious forest to me. I know enough to recognize it is full of trees and that's about it. :D

[Larrin]

Very cool. Thank you for sharing and for hosting the site!

I work with metals and love the field but steels are like a mysterious forest to me. I know enough to recognize it is full of trees and that's about it. :D

Every type of material or metal is different. And there are multiple types of steels that are very different from each. Designing automotive sheet steel is very different than tool steel for knives.

[Eli Chaps]

Very cool. Thank you for sharing and for hosting the site!

I work with metals and love the field but steels are like a mysterious forest to me. I know enough to recognize it is full of trees and that's about it. :D

Every type of material or metal is different. And there are multiple types of steels that are very different from each. Designing automotive sheet steel is very different than tool steel for knives.

Indeed. I play in the ultra-high purity world of various metals and while they can have base things in common they are also vastly different from one another. And then steel is yet another animal all unto itself. Really enjoying the articles!

[Larrin]

Thanks Eli.

[JD Spydo]

Another blade steel that Spyderco used years ago and I still have a few of the folders made with it>> I'm speaking of ATS-55 which also has a cobalt content in it as well.

Now I believe that Spyderco quickly changed over to VG-10 because it proved to be better in a few categories. Myself I still like some of my older Spyders with ATS-55 and I particularly like the fact that ATS-55 is proven to be a good steel for Spyderedges ( serrated edges).

The Spyderco ATS-55 era was a short one but a very memorable era needless to say and many collector pieces come from it.

[sal]

We tested ATS-55 and VG-10 during the same period. ATS-55 was made specifically for Spyderco by Hitachi. We had to commit to a large purchase and we used it for many models. In the end, we decided to use Takefu's VG-10 as a base steel for Japan models.

sal

[Larrin]

Another blade steel that Spyderco used years ago and I still have a few of the folders made with it>> I'm speaking of ATS-55 which also has a cobalt content in it as well.

Now I believe that Spyderco quickly changed over to VG-10 because it proved to be better in a few categories. Myself I still like some of my older Spyders with ATS-55 and I particularly like the fact that ATS-55 is proven to be a good steel for Spyderedges ( serrated edges).

The Spyderco ATS-55 era was a short one but a very memorable era needless to say and many collector pieces come from it.

Because of the small cobalt content and also the listed copper, it is likely that the cobalt addition is because of potential "hot shortness" from copper. Either cobalt or nickel additions help with copper-induced hot shortness.

[sal]

Thanx Larrin,

Good info. And thanx for sharing. We've got lock of steel junky's that hang out here and we appreciate the educated information.

sal

[crazywednesday]

Great article. Thanks for posting.

[JD Spydo]

We tested ATS-55 and VG-10 during the same period. ATS-55 was made specifically for Spyderco by Hitachi. We had to commit to a large purchase and we used it for many models. In the end, we decided to use Takefu's VG-10 as a base steel for Japan models.

sal

Yeah Sal I remember you telling us that some time ago but I couldn't remember exactly what the rundown was. Now this is coming from a VG-10 fan but I will say that personally I always liked ATS-55 and I've still kept many of my ATS-55 models and have no plans on letting any of them go. I particularly like it's performance in Spyderedge>> but I was just using my old C-44 Dyad the other day and the plain edged blade did an excellent job of cutting up meat.

With many of the newer blade steels that people seem not to like as well I'm wondering if ATS-55 wouldn't still be a good selection for some of the less expensive models. I can think of a lot of steels that I like less than ATS-55 and I've for a long time wondered what a fixed blade ATS-55 model might be like in combo edge or plain edge.

Interesting thread and I still see why VG-10 is still in the main line up.

[shunsui]

Would love a mule team knife in ATS-55. Too bad about the logistics.

[Ed Schempp]

Thanks Larrin, I'm looking forward to reading your efforts.

[Larrin]

I'm looking forward to reading your efforts.

Thanks Ed, that means a lot coming from you. :)