As mentioned, Dan is a heck of a guy. He was very helpful, and really a fount of information. For reference for the others who need help with similar projects, here's a brief synopsis of what I gathered from my conversation with Dan, who took a good amount of time out of his day to explain a good bit about 3V to me. I'm definitely quite excited to do more work with it.
Anyways, Mr Keffeler explained to me that I'm actually focusing on the wrong things. The Rockwell content (and the length of the blade, for that matter) aren't actually as important as I'd thought, and instead, I should be focusing more on the actual process that gets used. This is probably a no-brainer for many of you, but hadn't really occurred to me. Specifically, the key factors are the austenizing temperature and the soak time. 3V can take austenizing temps from around 1870 degrees up to 2100, from the rough numbers Dan gave me, and the lower temperatures will emphasize toughness, while the higher ones will emphasize abrasion resistance. Depending on the application, you may choose to use a different austenizing temperature. Since swords need higher toughness, Dan recommends leaning towards the lower range of austenizing temperatures (and if you want the protocol that he and Brad have tested over time, you can actually just let Brad know to use the same protocols as Dan uses on his blades, and then you just don't have to worry).
The soak time, as I understood it, needs to be sufficiently long enough that you get even distribution of the solution. I didn't really understand this part as much, although a later question about differential tempering suggested to me that it has to do with appropriately even distribution of carbon content to the various carbides, so that it's as even as possible throughout the entirety of the steel. As a consequence, Dan explained that 3V is very difficult to forge (or differentially temper). Where simple carbon steels can be forged more easily, it's hard to get that even distribution of carbon across the various carbides in a more complicated steel such as 3V. I don't have the background in metallurgy yet to really make full sense of that, but hopefully someone who knows more can elaborate and correct any misapprehensions I may have come up with. Anyways, Dan suggests around a half hour soak time for a sword, or other blade that you want to be really tough.
The cool thing about 3V seems to be that it's tough enough, using the lower austenizing temps, to still hit high RC. While you can temper lower, of course, you get the most out of the steel if it's tempered high enough, and will still hold a good edge. Dan explained that he's tried a wide array of different protocols, and tempering at higher RC's seem to result in a tougher sword that holds a good edge. So, ideally you'd use a lower austenizing temperature, but you can still temper to 60 RC, and even higher (up to around 62 if I recall correctly).
The other part of our conversation that really struck me is that 3V tempering level is around 900 degrees, which means that, unlike the 5160 and 1095 I've been working with thus far, I can actually do more aggressive grinding post HT if necessary, without ruining the temper. 5160, after all, starts to have issues around the 350-400 degrees. Dan also clued me in that just changing colors to blue or whatever, won't ruin the temper, since it's got to get red to start causing issues. That's pretty cool, because it means I can use the belt grinder on low speed to set my preliminary edge bevel, without as much risk of ruining the temper on the edge.
He also noted that the length of the blade doesn't really matter as much as I'd thought, because you're setting the toughness with the austenizing temperature, and the goal of the process is to get the appropriate structure evenly throughout the blade. A longer blade just means more material, but doesn't change the need to maximize what you get out of the steel.
So, it seems I can actually get an RC of 60, but still retain maximum toughness. That's pretty exciting to me, and I'll be interested to see what my sword will be capable of (if I can get a decent edge geometry, of course, that will be ideal). Thanks again to Dan for walking me through this information (and please feel free to correct anything I got wrong here), and hopefully it will be helpful to other amateurs like myself. Cheers!
I would very much recommend calling Brad Stallsmith at Peters' and asking his advice :thumbup: By all means, please let us know what he says!
