Vanax 75, the TilT had Vanax 75. You could have taken a picture of the TilT in dog crap and it still wouldn't have been easier to get. Someone correct me if i'm wrong, but I don't think you heat treat Vanax because of the nitrogen, it replaces the carbon for hardness.
Vanax 75 is no longer available to my knowledge and only Vanax 35 is, Vanax 35 is now, just called Vanax.
Here are the two compared:
zknives.com Vanax 35, Vanax 75 graph
Vanax heat treat recommendations are:
The recommended austeni-tizing
temperature is 1080°C (1975°F) with
30 min holding time followed by deep cooling
at -70°C (-95°F) or preferably in liquid nitrogen to reduce retained austenite content to a
low value.
For best corrosion properties low temperature tempering at 200°C (390°F)/2 x 2h is
recommended. The hardness is then 5859
HRC. If a lower hardness of 5556 HRC is
preferred use 1050°C (1920°F) instead of
1080°C (1975°F). If product application
conditions require a higher tempering temperature Uddeholm Vanax 35 can be tempered
up to 450°C (840°F) or even 500°C (930°F)
without significant loss of corrosion properties.
As the steel will contain ca 10% retained
austenite after the recommended heat treatment procedure, 1080°C (1975°F)/30 min +
DC + 200°C (390°F)/2 x 2h, the dimensions
will decrease 0.1% after heat treatment.
Enough material must thus be left to accommodate for this shrinkage in dimension.
Even if you replace the carbon with nitrogen it still needs to be hardened and what you said about the carbon in Vanax 75 Is only partially true. It still has .20 carbon (it does have 4.20 nitrogen though). I'm pretty sure the only steel that compleatly replaces carbon with nitrogen is H1. take this with a grain of salt, I'm by no means an expert on steels.
A high percentage of Carbon is replaced in certain steels, but no, none of the Nitrogen containing steels completely replaces all the Carbon.
Here is the most popular and available steels for knives containing Nitrogen:
zknives.com Vanax35, Nitrobe 77, H1, X30CrMoNi1-5-1, 14C28N
Nitrogen has significant advantages though and according to: Roman Ritzenhoff and André Hahn, Unknown Date, Page 55. Corrosion Resistance of High Nitrogen Steels, Energietechnik-Essen GmbH, Germany.
"Nitrogen in low alloy steels is undesirable due to the formation of brittle nitrides. However,
the use of nitrogen in high alloy steels has an array of advantages that makes it appear
interesting as an alloying element. In referencesone find this sufficiently researched, so that
in this situation only the most important points need to be summarized [Dailly & Hendry,
1998], [Energietechnik-Essen [ETE], 2011], [Allianz Industrie Forschung [AIF], 2003]:
 significant increase of strength without restricting ductility
 Improvement of corrosion resistance
 Increasing the high temperature tensile strength
 Extended / stabilized austenite form
 no formation of tension induced martensite with high cold working rates
 Inhibits the discharge of inter-metallic phases
These as HNS-Alloy (High Nitrogen Steels) specific material group are characterised
through an interesting material profile, i.e. a combination of strength and corrosion
resistance"
If one goes a bit further and look into the patent information of Vanax one can read the following:
United States Patent: US 8,440,136 B2. Column 3
"It is known from the article In?uence of nitrogen alloying
on galling properties of PM tool steels, 6th International
Tooling Conference, Karl stad Universitet 2002, that nitrogen,
by together With carbon combining With vanadium in order to
form M(C, N) carbonitrides and M6C catrbides, has a positive
effect on the anti galling properties of a tool steel."
United States Patent: US 8,440,136 B2. Column 4
"Carbon should primarily exist in the steel according to the
invention at a content that is adequate for it, together With
nitrogen in solid solution in the matrix of the steel, to con
tribute to giving the steel, in its hardened and tempered con
dition, a high hardness, up to 60-62 HRC. Carbon can also be
included, together With nitrogen, in primary precipitated
M2X nitrides, carbides and/or carbonitrides, Where M is
essentially chromium and X is essentially nitrogen, as Well as
in primary precipitated MX nitrides, carbides and/or carbo
nitrides, Where M is essentially vanadium and X is essentially
nitrogen, and be included in possibly existing M23C6 and/or
M7C3 carbides. "
BTW, H1 was pretty much at the very bottom.
The inclusion of Nitrogen into a steel is very beneficial from my understanding, however, as with other steels it seems Vanadium content will have a large impact on Wear Resistance, and this is what Ankerson tests show and confirm, the leading edge retention steels in his tests tend to be high Vanadium content steels.
However, many feel that wear resistance is not as important as:
Sharpness
The ability of the steel to support a keen edge with razor sharpness. It also means that the knife will be easy to resharpen. This is important for all knives.
Edge stability
The ability for the knife edge to withstand edge rolling and edge micro-chipping. Rolled edges and micro-chipped edges are the most common reasons for resharpening. This is important for all knives.
More can be read here:
Sandvik knife steel Knowledge
I for one am glad that the steels currently available with Nitrogen do not have high amounts of Vanadium. Yes, these steels will not perform as well as other high Vanadium type steels in Ankerson's test, however, I believe they are more geared towards chipping resistance and high corrosion resistance then sheer wear resistance. Vanax (35) will most likely be the best wear resistant steel between Vanax35, Nitrobe 77, H1, X30CrMoNi1-5-1 and 14C28N.
H-1 though not as wear resistant as many of the other steels has its advantages with regards to Corrosion Resistance and toughness.
H-1 bends (plastic deformation) instead of breaking.
