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Oct 27, 2020
Not sure if this posted in the original location: will post it here. The Y-Start JIN02 is one of the knives that was discussed earlier in this thread that were advertised as having D2 steel, which were subsequently tested and found not to be D2. The tester suggested it was maybe 8Cr13MoV -- there's a lot of steels sold as a market equivalent to D2 but 8Cr anything is definitely NOT one of them, sooo if so that's a really bad look for Y-Start and consequently I stopped recommending them to people for cheapass but good knives. It really did surprise me at the time because Y-Start looked like it was one of the better new budget makers and I was using them for dyeing projects left and right. When I recently looked at the printout of the test of the JIN02's steel (I'd had one sitting around for a while and finally thought to dye it, so it was on my mind again and I went looking at the original info) it turned out that their 'smoking gun' that it wasn't D2 was that it had low vanadium -- like .10% - .15% or less, where AISI D2 should have at least 1% of it by weight. At the time I saw that and shrugged but didn't make much of it. But the problem is, AISI D2 is only one of the alloys that is sold on the global market as being the same thing as D2, and many of the others have specs that allow considerably less vanadium than D2 has. Since no one holds the patent or copyright or trademark for D2, no one can step up regarding one or more of these alloys and and say 'hey you can't sell that as D2!' The older a variety of steel is, the less likely it is to even have trademark support, and the more of these 'equivalent' cheaper alloys end up being sold as them. Long story short - based on the test results I'm inclined to think that it's at least as likely that the steel in the JIN02 is K110 as it is an 8Cr steel. K110 is considered a market equivalent to D2, so obviously if that's the case it doesn't cast Y-Start in nearly so bad a light. It is getting some name recognition now but when the JIN02 came out I can easily see someone going 'market it as D2, no one will know what K110 is'. That's how the knife business is. I don't really have a stake in exonerating Y-Start though -- they can fight their own battles -- and moreover I'd suggest anyone curious about this go look at the data themselves rather than just take my word for it based on my impression. But that's where I'm coming out on it. Basis: Still taken from the LTK video where he was going down the findings:
Readout: Carbon and some other elements can't be measured by the analyzer being used as LTK frequently reminds folks, so disregard it being missing even though we know carbon is a very important part of steel alloy composition. Notables from the assay: Molybdenum: 0.208% +/-.013 = 0.195% to 0.221% Niobium: 0.023% +/-.005 = 0.018% to 0.028% Nickel: 0.276% +/-.086 = .190% to .362% Manganese: 0.486%+/-.167 = .319% to .653% Chromium: 13.294%+/-.213 = 13.081% to 13.507% Vanadium: 0.141% +/-.061 = .080% to .202% Silicon: 0.402% +/-.072 = .330% to .474% and a whole bunch of elements which weren't detected. .4% Si is within what you'd call the expected range of contamination for silicon in steel - it's used in the manufacture of steel, and most of it is removed through varying steps but it's common for a certain amount of silicon to show up in the assays of most steels on the market even though it's not part of the official formula for it. The point is, readings of less than .5% silicon usually don't help us tell most alloys apart from one another, even though many steels have specs indicating .5% or less. The main idea is that unless you are working with a very clean process, it’s easy to end up with some stray Si embedded in the steel matrix, more or less than you intended to be in the formula. And at low concentrations its effects are negligible. The presence of niobium, on the other hand, would be surprising as an intentional addition in that few steels have it naturally. But at one fifth of a percent, it too is more likely to be down cross contamination from being smelted and cast and forged on equipment that also manufactures niobium steels like S35VN. I don't believe it appears in deposits of iron ore (edit: it doesn't, it appears in association with large magma intrusions through other types of stone). LOD means that if that element is present in the assay sample, there is less of it than the lower limit of detection (aka the LOD, or 'detection limit', the smallest amount that the sampling gear can actually pick up and register as being present. Theoretically there could be some small amount of any of those elements present in the sample, so long as it was less than the LOD. But at those levels, it also wouldn't matter much to the final nature of the alloy until the world gets much much much better at arranging the molecules in forged steel, so for now fuggedaboudit. That leaves us with: Molybdenum: .195% to 0.221% Nickel: .190% to .362% Manganese: .319% to .653% Chromium: 13.081% to 13.507% Vanadium: .080% to .202% Comparing these to the official formula for a few different D2 steels, 8Cr13MoV, and 8Cr14MoV (thank you once again
A quick check tells us: Molybdenum: .195% to 0.221% = Both 8Crs, K110 fall within this range Nickel: .190% to .362% = 8Cr13MoV, K110 fall within range Manganese: .319% to .653% K110, SKD11 fall within this range Chromium: 13.081% to 13.507% = Both 8Crs fall within this range (K110, SKD11 juuuust miss it) Vanadium: .080% to .202% = all steels sampled fall within this range 8Cr13MoV: four hits out of five 8Cr14MoV: three hits out of five Cr12MoV: one hit out of five K110: four hits out of five SKD11: two hits out ot five So there's no one steel from this list is five for five. The Mn is way too low to be one of the 8Cr steels and the Cr is too high to be anything but one of the 8Crs. Loosening the ranges - I.e. allowing for the fact that the instrument’s calibration might be a bit off or such - doesn't help either 8Cr steels, which have a clear spec of 1% molybdenum. But it does help the case for K110. It ticks all other boxes. Its average Cr is 12% and max 13%; the sample’s detected Cr was 13.08% at the lowest. I looked through the other ‘D2’ specs seeing if I could find another better match - nothing better than K110 appeared though. And if you look at K110's spec sheet on zknives it's easy to see why it’s the only one that fits the assay. For a Bohler steel it's got a pretty wiiiiide range of acceptable alloy percentages. Bohler lists averages on their website, not the range of acceptable deviation from them which zknives does. Not what you really associate with the name but that's the power of marketing. On the other hand it's possible that K110 is meant to at least allow for the use of recycled steel. Right on if so. Doing that would necessitate the wide ranges of required values seen in the K110 spec -- the steels getting recycled typically come from a range of different alloys, i.e. whatever is getting thrown in the steel bin.... which means that for K110 to be economical it needs to allow for a wide range of overall alloy percentages for the common steel alloy elements in its steel formula. And the truth is the overall impact on the performance of the knife steel is probably something the average user would struggle mightily to identify. Who knows? Could it be something else? Sure. This is an armchair analysis, clearly. No steel I know of has a spec for .02% Nb but that doesn’t mean they don’t exist. Like I mentioned, steel can easily picks up traces of alloy while being forged, from bits of steel from previous runs on the same smelting, forging and machining equipment. And if the specs for manufacture allow for recycled steel as I said, maybe that batch of steel had some niobium steel go into it. It's also worth pointing out that the LOD for tungsten (W) for the assay gear is .5% by weight and many tungsten containing steels have, like, .2 to .5% tungsten in them - including market equivalent steels to D2. Having a finer instrument for detecting tungsten would help further differentiate this steel, but the assay we have doesn't register its presence below .5% by mass. On the other hand, low concentrations of tungsten will impact the alloy less than low concentrations of another alloy: tungsten is so much heavier than other alloy material that any given weight of it will have considerably fewer atoms of tungsten than a similar weight would have of Fe, Mo, Mn, V, Nb or really any other common alloy agent. You might be going 'how in the hell can something like Cr12MoV even be sold as an equivalent to D2 if it doesn't make as good a knife steel?' And if so, I'm there with you but you gotta remember -- the knife industry is the runt of the litter when it comes to the industries buying up globally produced steel, and the reason most D2 alloys are bought and sold and lumped together has to do with the kind of industrial tooling it can make and the fact that these alloys all air harden in a manner similar to D2. Those are the sort of demands that end up setting the price of market equivalents of D2 steel. Knifemakers with their comparatively miniscule purchases are more like bargain hunters when it comes to the steels they choose to use in production knives, hunting through the steels with prices set by bigger industries to find ones that make decent knives that will make their fans happy, but have a cost their accountants like.
Oct 27, 2020
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