Chrome Vanadium Steel

[Mumbleypeg]

The amount of Cr & V in 1095CV is too little to make it rust resistant.
kj

Correct. In fact it says Case CV steel is not rust resistant on the Case web site, and also on the paperwork provided in the box with the knife. http://www.wrcase.com/case_college/blades_steel/

Ken

That's probably true with regards to Case's "CV" in particular but why not just show some CV steel knives from different makers. After all, as they say "a picture is worth a thousand words" Here's Roland's (Kootenay Joe) ex-knife in CV steel which I believe sparked this discussion to begin with. It's from the late 1940s and it looks spotless.
CV Steel.jpg

The fact that Case advises their customers how to properly care for their CV steel blades by advising them it is more prone to rust than their various stainless steels (and therefore should be cared for accordingly) shouldn't be interpreted to mean it rusts more readily than non-stainless steel used by other makers. The Case web page I linked in a prior post in this thread gives some good info regarding pros and cons of the various steels used by Case, including edge retention and ease of sharpening in addition to corrosion resistance. Case says their "CV" steel does contain chromium and vanadium. Unfortunately other makers are no longer around today to testify what steel they used - we don't know whether it contains any chromium or vanadium or any other additives, or none at all. There may be exceptions but for most we can only speculate as to what steel was used.

I'm assuming by Felix's request to "just show some CV steel knives from different makers", the intent is for them to be non-stainless steel. Unless they are Case, for which we have at least some documentation, we mostly don't know if they are "CV" or not.

Here's a few rusty old Case CV examples. Some are newer vintage and some over 100 years old. Some carried and used extensively, with patina, and some near-mint, never carried. With possible exception of the pearl gunstock whittler (acquired within the past year) the others have been in my possession for many years so I can state from firsthand knowledge that none have recently been buffed. I do check them and "oil" them annually. The 3318 I got new in 1971, carried and used hard for several years before it was retired to the dresser drawer. You can see some evidence of pitting on it, about what would be expected from a hard-used non-stainless knife IMHO. However I can't recall it ever having active rust.

Ken

[kootenay joe]

Fine display of older Case knives.
Are Case knives either CV or Tru-Sharp, no 'pure' 1095 ?
When did Case first use C.V. steel ? i.e. was Cr & V. added to steel back in the early days of Case ?
kj

[Mumbleypeg]

What little I know about this topic comes from when I toured the Case factory about 10 years ago. During the tour we saw large rolls of steel stock in the warehouse area near the receiving dock. I asked the tour guide, long-time Case employee Whitey Peterson, if their CV steel (my favorite) had changed any since the Tested XX era. His reply was that it is the exact same steel and has not changed. He added that the formula and the supplier is proprietary to Case.

Ken

Blade steels currently used by Case are listed and described to a degree on their web site http://www.wrcase.com/case_college/blades_steel/. Scroll down past the pictures of blade types. There's no mention of "pure" 1095.

Ken

[SolWarrior]

Ken, those are some fine examples of very nice Case knives in different stages, from spotless to peppered patina. All of them are

[terryl308]

Very interesting subject discussed here. My take on it is, Case CV blades that have some patina or light rust is due more to the owners care of such blades rather than the small amounts of Chromium and vanadium. All the steel makers I have read about say it takes at least 10-14% chromium to make a blade "stainless steel". Some very examples shown here. Terry

[terryl308]

Very interesting subject discussed here. My take on it is, Case CV blades that have some patina or light rust is due more to the owners care of such blades rather than the small amounts of Chromium and vanadium. All the steel makers I have read about say it takes at least 10-14% chromium to make a blade "stainless steel". Some very nice examples shown here. Terry

[Mumbleypeg]

Very interesting subject discussed here. My take on it is, Case CV blades that have some patina or light rust is due more to the owners care of such blades rather than the small amounts of chromium and vanadium. All the steel makers I have read about say it takes at least 10-14% chromium to make a blade "stainless steel". Some very examples shown here. Terry

The best information comes from this chart http://knifeinformer.com/knife-steel-composition-chart/ posted previously by Tom (bestgear), and the info below the chart describing the attributes contributed by additives in steel. My take is that the amounts of chromium and vanadium in "CV" are added mainly to improve edge retention, hardness, and toughness - not to make it rust resistant (although it does imply any amount of chromium improves rust resistance).

However if enough chromium is added to make the steel "stainless" (according to the chart it requires at least 13% chromium) it also makes the steel more difficult to sharpen. This thread became focused on rust, and pretty much ignored other aspects such as brittleness, toughness, wear resistance (edge retention) and ease of sharpening. As some have pointed out, the tempering process used by the knife maker is an important factor as well. As with so many things in this old world there are trade-offs the consumer must weigh to make an informed buying decision. Whether one steel is better than another depends on what the knife maker does with it, its intended use and the user's personal preferences.

Ken

[kootenay joe]

This thread has been a big help to me. I now finally have some understanding of what "CV" steel is: basically it is tweaked 1095 or similar other steel. Tweaked to improve certain properties as stated in above post, not to try to improve rust resistance.
So, my conclusion is: CV is a good knife blade steel.
kj

[Colonel26]

Ya hit the nail on the head. Not stainless at all. Just a darn good steel.

[orvet]

This thread has been a big help to me. I now finally have some understanding of what "CV" steel is: basically it is tweaked 1095 or similar other steel. Tweaked to improve certain properties as stated in above post, not to try to improve rust resistance.
So, my conclusion is: CV is a good knife blade steel.
kj

I think you are right Roland. However, my personal preference is 1095 because of the experience I have had with new Case knives and CV steel that tended to pit more readily than 1095 steel.