Is Nitro-v more corrosion resistant than 440c in a salt water environment? Why or why not?

T

Tyler.t76

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Is nitro-v more corrosion resistant that 440c? I’m asking because I recently got into a discussion about it where the other person was very adamant that nitro-v was more corrosion resistant that 440c even going as far to say 440c was not even close. His reasoning was that nitro-v “has a very high level of chromium and was developed to perform in salt water” which the steel only has a 13% chromium content, as well as .11% nitrogen which knife steel nerds says would equate to about a 1.75% boost to chromium content. I’m 100% positive it is not the most corrosion resistant blade steel, and pretty sure 440c would be more resistant based one everything I’ve read. So I’m curious what’s the answer and why? What factors contribute to either being more resistant? Very interested in the topic. I’m falling into the rabbit hole of metallurgy for blade steels haha.
 
According to the chart in Larrin's book, they are both very close to each other. 440C has a score of 12.5 and Nitro V has a score of 12.0. Just remember that carbon content plays a huge role in a steel's resistance to staining. The more carbon, the more the chromium is tied up in carbides. Like how ZDP189 has a whopping 20% chromium, but an extremely high 3% carbon, and is not that stainless at all.
 
Knife steel nerds rates 440c at 12 .5 and Nitro-v at 12. Higher is better. It has to do with the amount of chromium in solution after heat treating. Sandvik developed 14c28n as an upgrade to Nitro-v type grades for an upgrade in corrosion resistance, KSN rates 14c28n at 13.9. There are several grades with better corrosion resistance than either 440c or Nitro-v.

Hoss
 
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DevinT said:
Knife steel nerds rates 440c at 12 and Nitro-v at 11,5. Higher is better. It has to do with the amount of chromium in solution after heat treating. Sandvik developed 14c28n as an upgrade to Nitro-v type grades for an upgrade in corrosion resistance, KSN rates 14c28n at 13.9. There are several grades with better corrosion resistance than either 440c or Nitro-v.

Hoss
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thanks. Assuming the heat treatment is perfect, could you assume that chromium percentage and nitrogen are the only two factors you need to look at to determine which steels would be more resistant?
 
Stuart Davenport Knives said:
According to the chart in Larrin's book, they are both very close to each other. 440C has a score of 12.5 and Nitro V has a score of 12.0. Just remember that carbon content plays a huge role in a steel's resistance to staining. The more carbon, the more the chromium is tied up in carbides. Like how ZDP189 has a whopping 20% chromium, but an extremely high 3% carbon, and is not that stainless at all.
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Thanks, good to know there’s a chart in knife engineering wish I would’ve known that earlier haha. That ZDP189 thing is really interesting. Is the carbon to chromium ratio linear when it comes to the corrosion resistance number? Say for example you had something .6% carbon and 13% chromium, and another 1.2% carbon and 26% chromium, would those two steels be equally corrosion resistant?
 
Tyler.t76 said:
Thanks, good to know there’s a chart in knife engineering wish I would’ve known that earlier haha. That ZDP189 thing is really interesting. Is the carbon to chromium ratio linear when it comes to the corrosion resistance number? Say for example you had something .6% carbon and 13% chromium, and another 1.2% carbon and 26% chromium, would those two steels be equally corrosion resistant?
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That's above my pay grade, really, but I would think in your example, the 1.2% C/ 26% Cr steel would be WAY more stain resistant than your 0.6% C/ 13% Cr.
 
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