Spyderco Forums

I generated a simple method for predicting the corrosion resistance of knife steel, and then ranked them all. https://knifesteelnerds.com/2019/01/14/ ... esistance/

LC200N would be a great choice.

Awesome, thanks for your hard work.

LC200N is the same as Cronidur 30

Based on the ones I own and use allot from greatest to least corrosion in this order based upon real use and observation.

H1 / LC200N Cant get either to rust although I think something rusted on top of my H1 as there are rust marks in the same area on both side of the blade in the same area like it was left trapped inside something will have to flitz it tonight and see.

S110V

S90V

CTS-204P / M390

M390

S35VN

Elmax

VG-10

S30V

Another great article. I long ago opted out from carrying ZDP-189 around saltwater. While classified as stainless, I found it rusts and pits much quicker than most other "stainless" steels. Your explanation helps to better understand why. Though the list confirms many of my experiences, I'll definitely keep this for future reference. While other factors affect steel and knife choice, this is an excellent guide to stainless qualities. Thanks for your time, effort, and expense in helping us to better understand steel qualities.

Apologies did not realize you took the time to make such a nice article. Interesting to see where things landed.

Thanks for the great article, Larrin.

I have a question: how do your PREN approximations ....

- Acetic acid = Cr + 0.45(Mo + 0.5W)
- Aqua-Regia = Cr + 0.79(Mo + 0.5W)
- Pitting potential = Cr + 2.6(Mo+0.5W)

... work for steels with very high Tungsten content ? For example, CPM Rex 45 with 6.25% W, or Maxamet with 13% ? We haven't seen a lot of corrosion on knives in those two steels in practice (yet), and I was wondering if Tungsten was to take credit for this.

Thanks,

Roland.

Thanks Larrin, great article!

LC200N C 0.38 Cr 15.08 Mo .95 N .50 Mn 1.00

Cronidur30 C 0.25 to 0.35 Mn 1.00 Si 1.00 Cr 14.0 to 16.0 Mo 0.85 to 01.10 Ni .50 N 0.30 to 0.50

As always, many thanks Larrin. :)

ferider wrote: ↑

Mon Jan 14, 2019 3:02 pm

Thanks for the great article, Larrin.

I have a question: how do your PREN approximations ....

- Acetic acid = Cr + 0.45(Mo + 0.5W)
- Aqua-Regia = Cr + 0.79(Mo + 0.5W)
- Pitting potential = Cr + 2.6(Mo+0.5W)

... work for steels with very high Tungsten content ? For example, CPM Rex 45 with 6.25% W, or Maxamet with 13% ? We haven't seen a lot of corrosion on knives in those two steels in practice (yet), and I was wondering if Tungsten was to take credit for this.

Thanks,

Roland.

Maxamet is in the table. Rex45 is not but it is a Mo-W steel just like M2 and M4 (plus cobalt) so calculations would probably be similar to those two.

steeljustice wrote: ↑

Mon Jan 14, 2019 3:26 pm

LC200N C 0.38 Cr 15.08 Mo .95 N .50 Mn 1.00

Cronidur30 C 0.25 to 0.35 Mn 1.00 Si 1.00 Cr 14.0 to 16.0 Mo 0.85 to 01.10 Ni .50 N 0.30 to 0.50

I believe you meant to put 0.30C and 15.0Cr unless you have a different composition than the datasheet that you are referencing.

Larrin wrote: ↑

Mon Jan 14, 2019 4:33 pm

ferider wrote: ↑

Mon Jan 14, 2019 3:02 pm

Thanks for the great article, Larrin.

I have a question: how do your PREN approximations ....

- Acetic acid = Cr + 0.45(Mo + 0.5W)
- Aqua-Regia = Cr + 0.79(Mo + 0.5W)
- Pitting potential = Cr + 2.6(Mo+0.5W)

... work for steels with very high Tungsten content ? For example, CPM Rex 45 with 6.25% W, or Maxamet with 13% ? We haven't seen a lot of corrosion on knives in those two steels in practice (yet), and I was wondering if Tungsten was to take credit for this.

Thanks,

Roland.

Maxamet is in the table. Rex45 is not but it is a Mo-W steel just like M2 and M4 (plus cobalt) so calculations would probably be similar to those two.

Don't mean to argue, Larrin, have wondered about these PREN indicators before ..... The Maxamet W contents in the table is not what I see on Carpenter's website (https://www.cartech.com/en/product-solu ... amet-alloy). Per Carpenter, it has 13% W, and - for example - the Pitting potential PREN should be 21.3, higher than any other entry in the table. What am I missing ? Thanks.

ferider wrote: ↑

Mon Jan 14, 2019 4:53 pm

Don't mean to argue, Larrin, have wondered about these PREN indicators before ..... The Maxamet W contents in the table is not what I see on Carpenter's website (https://www.cartech.com/en/product-solu ... amet-alloy). Per Carpenter, it has 13% W, and - for example - the Pitting potential PREN should be 21.3, higher than any other entry in the table. What am I missing ? Thanks.

Most of the values in the table do not match the bulk composition, as it is a calculation of alloy in solution after heat treatment.

I see. Thanks !

think these are the Data sheets i found.
http://www.zknives.com/knives/steels/lc_200_n.shtml

http://www.righton.co.uk/datasheets/Bea ... 8_405.ashx

This is awesome! Very nice work! Thank you.

Thank you Larrin. Edge-holding is important to me but my two main big properties I like in a knife steel are corrosion-resistance and toughness.

By the way everyone, look which steel is nearly at the top of the chart: SANDVIK 14C28N! Just as I thought! :) :) :)