INFI and seawater

SALTY

SALTY

Gold Member
Joined
Mar 19, 2000
Messages
5,803
We have nuclear powered subs and nuclear powered aircraft carriers and they seem to do just fine in salt water environments.

So, does anyone have experience with INFI and modified INFI in and about seawater applications?

Any information on how INFI and mod/INFI compare to Talonite, 154CM/ATS-34, 440A-C, 420-HC/425 and "carbon steels?
 
I've heard that INFI has rust-resistance similar to D2 or maybe even ATS-34. Cliff Stamp has done work in this area (check out his site). Cliff found some interesting results. For example, when INFI does rust, it usually doesn't affect the edge much (I'm not sure why). Also, the rust seems to come off quite easily when it does come.

I'm not sure if you've seen this post, but it may be of interest to you:

http://www.bladeforums.com/ubb/Forum39/HTML/001257.html
 
Subs certainly are able to enjoy a long service life in a seawater environment, but don't forget about the sacrificial anodes that make it all possible (probably not a very aesthetically pleasing accessory to have Jerry add to your BM-E
wink.gif
biggrin.gif
).

Someone recently mentioned using their Busse as a dive knife and reported that with just some routine post-dive maintenance, they encountered no corrosion problems.

Just for the record, Talonite is all but impervious to salt water.

------------------
Semper Fi

-Bill

[This message has been edited by Bronco (edited 05-21-2001).]
 
I have used both M-INFI and INFI in wet and dirty conditions, including around and in saltwater. I have also done long soaks (24 hour) on both blades in salt water solutions (1tbsp per cup, or similar, which is really salty). The M-INFI blade was used for over a year without oil of any kind because the person who I lent it to thought it was stainless.

I have noticed that INFI will resist rust stronger than most plain carbon or low alloy steels (L6). For example, a few weeks ago I spent about 6 hours in the rain with a Battle Mistress, PAB from Strider, a Hatchet from Gransfors Bruks and a few saws. What I found was that while in use chopping (alternating every other piece of wood, about 10 minutes in between use per rotation) neither blade rusted. However as soon as I switched to the saws the Gransfors Bruks hatchet rusted readily.

This really isn't a surprise as the hatchet it is most likely a bandsaw steel (L6-like) or something very close to it and they will rust readily if exposed to water. If you really want to see just how easily such steels can rust thenexpose them to fruit juices, the acids will put a patina on them *very* quickly*, just a few minutes. I cut up an apple with one awhile back and before I the tv program I was watching went to commercial all the contact area had turned.

In regards to comparing INFI/M-INFI to stainless steels, most stainless knife alloys would resist the initial formation of rust stronger than INFI/M-INFI. However based on the long soaks I have done, they tend to take much more extensive damage when they do rust. Mainly they suffer extensive pitting which cannot be removed without a surface lapping (or a chemical treatment which will leave pockets in the finish).

For example using identical salt water solutions on VG-10, ATS-34, D2 and INFI. The INFI blade after a mild cleaning (a few passes with a worn scotchbrite pad) was left with a smattering of small black oxide specs (<0.2 mm in diamater). The other blades had sufrace corrosion that was extensive (>cm in size) and deep enough that even a mild sanding did not remove it (the D2 blade was more extensively damaged than the stainless blades). Most of the specs on the INFI blade (Battle Mistress) came off with use. The only ones that remain are not in frequent contact areas.


I should qualify though, that blades will only rust if left *unused* in corrosive enviroments. The hatchet I mentioned in the above for example was cleaned of all the surface rust from abrasion when I switched back to chopping. As well the blade that rusted after cutting the apple was left unused for about 10 minutes after it sectioned the apple.

One other thing, INFI is not as corrosion resistant as the more rust resistant stainless alloys like 440A. I have a 440A fillet blade in a salt water solution now for a week and it shows only a slight surface rusting in a few areas that would wipe off with a cloth. The piece of BG-42 I have in with it is completely covered in deep black and orange oxide. Most high end cutlery stainless blades do not leave a significant amount of free Cr in the steel so their corrosion resistance is low. Doesn't do the steel any good corrosion wise if the Cr isn't free, regardless of the percentage in the mix.

-Cliff


[This message has been edited by Cliff Stamp (edited 05-22-2001).]
 
One thing to remember about soaking tests, If the IIQ (item in question) remains submerged it is far different that submersion then being exposed to air, then submerged, then air, etcetera, etcetera.

Items that are raised from the sea sometimes look surprisingly good until they surface ... then the real damage starts. A common technique for preserving an item (like a ship's cannon, for example) once raised is to immediately submerge it in seawater and keep it that way until it can be treated properly.
 
I have done soaks completely underwater as well as partially submerged as well as periodic removal and submergence. I have also done pseudo-soaks by wrapping the blade with cloth, soaking it and periodically applying more solution as it dries. I have also dipped blades, shook them off, and put them wet in the sheath, and as well tried a fresh water rinse. I have also looked at rusting beyond immediate exposure by (a) using a rinse, (b) wiping the blade down, and then seeing how the rust continued to develop. And have done the above both inside (basement) and outside.

The rate and extent of the corrosion is greatly effected by all of the above. But it doesn't do much to the relative performance. If you are doing a comparion just make sure that you are doing similar things to both blades. Taking one up periodically for examination and leaving the other in the solution for example will skew the results horribly. As well be careful not to prepare the blades before hand differently, extensively handle one and leave the other clean for example.

Note the container that you have the bath in can greatly influence the rate of corrosion if it is metallic. I switched to plastic after some early soaks which did nothing but destroy the pans the knives were in as they rusted not the blades.

-Cliff
 
This is all good but......

Has anyone around here actually USED their Busse around seawater for any period of time?
 
I used my SH II for 2 weeks in Chile on freshwater and ocean down the Palena to the Pacific. However, I managed to keep the Busse fairly dry; my Blackwood talonite took the brunt of wet duty. That's why I didn't pipe up earlier: not enough real salt water exposure to be overly helpful. Not yet, at least. I did notice on that trip, and on others [freshwater and rain] that some small, light rust spots did form, but they came off very easily with light cleaning, with no damage at all.

[This message has been edited by HJK (edited 05-26-2001).]
 
Yes, my brother often swims in seawater and has carried the Basic #7. Any small amount of corrosion that developed was quickly burnished off during use which was frequent and heavy. I have also used the Battle Mistress around and in direct exposure to seawater, mainly to fillet fish as I was curious how difficult it would be compared to a fillet blade (very). It would experience some black oxide spotting and some discoloration due to rust with prolonged exposure when I didn't clean it, which I never did as I was curious as to how it would be effected. Most of the corrosion would come off with cleaning, and what was left would not survive the blade being used.

-Cliff
 
<font face="Verdana, Arial" size="2">Originally posted by Cliff Stamp:
I have a 440A fillet blade in a salt water solution now for a week and it shows only a slight surface rusting in a few areas that would wipe off with a cloth. The piece of BG-42 I have in with it is completely covered in deep black and orange oxide. Most high end cutlery stainless blades do not leave a significant amount of free Cr in the steel so their corrosion resistance is low. Doesn't do the steel any good corrosion wise if the Cr isn't free, regardless of the percentage in the mix.

-Cliff
</font>
Click to expand...

Very interesting ... especially the more extensive pitting damage to "stainless" stuff vs. INFI. Just shows me how much I have to learn.

The "free chrome" thing ... would be interesting to soak 440A and 440C from say the same mfg... since ostensibly both 440's would have the same starting chrome content if the mfg got them from the same source, i.e. 16% to 18% chrome.

Since 440A has 0.65% to 0.75% carbon, and 440C has 0.95% to 1.2% carbon, this would suggest that 440C will have more chrome carbides in the matrix, leaving less chromium around to oxidize into chrome oxide, said oxide layer being what our plant metallurgist tells me is primarily responsible for general corrosion resistance of high chrome alloys.

Crucible indicates that 420V exceeds the corrosion resistance of 440V, this despite starting chrome in 420V of ~14% and starting chrome in 440V of 17%. May be a similar story... 420V must use it's carbon preferentially to bind up with Vanadium (9%)in making Vanadium carbides, leaving more free chrome around to form chrome oxide vs. what happens in 440V with "only" 5.5% Vanadium. If this is not the case, I am again confused and in search of something that explains the "truth" a bit closer.

Similarly, Crucible gives their regular 420 "Prem" (similar to 420Mod & 420HC) about double the corrosion resistance rating of 440C. Regular 420M only has 0.4% carbon and 12%-14% chrome... but apparently plenty of chrome is around for chromium oxide vs 440C, even though 440C starts at 16-18% chrome.

We see alloy compositions in weight percent I believe. But molecularly, this stuff binds up in different ratios I'm sure... would be nice to see what relative ratios that chrome, moly, & vanadium bind up with carbon, converted to weight %. Better still, alloy compositions given in terms like:

5% free chrome
7% chrome carbide
3% vanadium carbide
4% moly carbide

By the way, chrome only oxidizes (or "rusts") to chromium oxide on the surface. That chrome oxide layer can be worn off by use, but reforms fairly quickly if free chrome is around. During alloy formation, Manganese and Silicon are two of the elements used as an oxygen scavengers, i.e. they help remove oxygen from molten liquid, how? I dunno yet... do they grab oxygen and oxidize in molten state? Or do they cause it to off-gas somehow?


[This message has been edited by rdangerer (edited 05-28-2001).]
 
You must log in or register to reply here.
Back
Top