I had considered attempting to come up with my own unique steel compositions, but just wanting to do so doesn't mean that you have something unique to offer. However, spending all this time on writing about different knife steels eventually led to a series of epiphanies about possibilities in steel design that have not yet been explored.
Epiphanies
Early powder metallurgy stainless steels used high chromium content (17-20%) for corrosion resistance in combination with vanadium for wear resistance. These included steels like S60V, Elmax, and M390. However, these steels have relatively low toughness from the relatively coarse microstructure that results from a large percentage of chromium carbides. Non-stainless powder metallurgy steels like CPM-4V, CPM-3V, and Vanadis 8 have smaller vanadium carbides only which give them a superior combination of toughness and wear resistance. The small, but very hard, vanadium carbides, offer superior wear resistance for a given amount of carbide. And less carbide means higher toughness. Crucible later developed steels like S90V and S30V which had less chromium (14%) for less chromium carbide which improved properties relative to the higher chromium stainless steels. The corrosion resistance was not necessarily reduced when compared with the higher chromium steels because only so much of the chromium is 'in solution' to contribute to corrosion resistance. Somewhere in the range of 10-13% in solution is common, with the rest tied up in carbides. Which means a stainless steel can be developed with only about 10% chromium as long as all of it is in solution after heat treatment.
Actually, it could be a little bit less because some of the steel is carbide. If the steel has 10% carbide, that leaves 90% matrix, so the 10% chromium could end up being as high as 11.1% in solution (10 divided by 0.9).
I found that if I kept the carbon content into a relatively narrow range, a sweet spot would be found where there would be enough carbon (for hardness) and chromium (for corrosion resistance) in solution while also having a combination of hard vanadium and niobium carbides for the optimal balance of wear resistance and toughness. At least, according to the software.
Requirements for the properties of new steel
1. Wear resistance and toughness at the level of CPM 10V and K390.
2. Corrosion resistance at the level or just above the S45VN and M390.
3. Hardness 60-64 HRC.
Composition
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Hardness
The hardness of steel primarily depends on the amount of carbon dissolved in austenite when heated.
The carbon content in austenite reaches 0.4-0.5 %. MangaSlice can reach relatively high hardness, over 63 Rc without cold treatment, and over 64 Rc with a cold treatment, even reaching 65 Rc.
The wear resistance of steels depends on hardness and to a greater extent on the type and volume of carbides: the larger the share of carbides and the more hardness of carbides, the higher the wear resistance.
The toughness is also strongly connected with the volume of carbides: the smaller the share of the carbide phase, the higher the toughness.
From the point of view of comparison with other steels, Mangaslice, as expected, is very similar to the CPM-10V and K390 in terms of toughness and wear resistance. In all these steels there are only solid vanadium carbides in the amount of 12-13%.
The toughness and wear resistance of the Mangaslice is higher than that of the S45VN, M390.
Corrosion resistance
The Pitting Resistance Equivalent Number (PREN) exceeds or equal to indices of steels such as S45VN and M390. Surprisingly excellent corrosion resistance to Mangaslice is due to the lack of chromium carbides compared to other stainless steels. Chromium carbide leads to the formation of locally impoverished areas of chromium surrounding carbides, since carbides are formed due to the removal of chromium from the matrix.
Summary and Conclusions
Steel has limited availability and is so far available in my sick imagination.
