Some destruction testing!
So I bought some steels form Hitachi to test in san mai.
The idea will be to use it with my damascus as cladding and try some stainless clad too.:) I went for the YCS2 and blue paper 2 as they are both oil quench steels and can Ht in the same range as my damascus steels. The tempers also look good. At a 200 degree temper the clad should be about 58hrc, the core 62/63.
I got some billets together in both steels, just to test I used en9 cladding and a layer of 75ni8 then blue paper/YCS2 core.
They both got 3 normalizing cycles, then ht'd in the digi oven towards the lower end of the recommended temperature range. Both were tempered at 200 degrees. My thoughts are I will find what results I like best then get some hrc testing done to check all is as I assume.
Ground them up and got them honed. I expected the blue paper core to be a pain to hone, it was very nice even at this hardness, easier than the YCS2. I like the edge off it too.
Next I started trying to chip the edges. I could chip the edge of the YCS2 core with a lighter and considerable pressure. The chips were coming off LARGE, with a little distortion present before the chip. I couldn't chip the blue paper core with a lighter, I had to use the edge of a cast steel vice. Chips with much more limited in size, again with a little distortion present before the chip. Neither steels showed signs of microchipping in chopping tests prior to destruction I should add, so quite stable really considering the hardness.
Next I did a bend test on each, they both got to about 50 degees before giving out in a clean break about 1/3rd of the way from the tip. I'd hoped for better with the cladding.
Both showed a little distortion towards the break. A break though would not occur during normal kitchen use, loosing a bit off the tip would be very probable though at some point, if you dropped it in the sink or poked the tap with it. Loosing tips does seem common with 61hrc+ Japanese or custom kitchen knives?
The grain structures are interesting, even just through a x10 Loupe, the core is visibly smaller grain to the cladding. The Blue is visibly smaller grain to the YCS2, though this could be variations in HT. Must add a microscope to the lottery shopping list:D
Not very scientific yet, but just getting a taste of the steels. HRC sample tests will follow. I've made another of each and got the blue one ground, i've been using it daily for a week and it still pops hairs off my arm.
Generally at the moment, I'm really liking the Blue, though I'll try both with a slightly higher temper and the full damascus clad. I have a feeling I will like the blue best at around hrc61/62 and the YCS2 a little lower 59/60. The blue is four times the price of the YCS2:O Both are very over priced, but as a core material it could work out ok.
Must get myself some of that V2 to try if they will sell me any.
Blue chipping, repairable, and only possible with some serious force.
Monster chips in the YCS2, some force or misuse required.
YCS2 Analysis: C 1%; Si 0,5%; Mn 1,1%; Cr 0,6%, P<0,03%, S<0,003%.
Blue Paper 2 Analysis (C = 1,1 - 1,2%, Si = 0,1 - 0,2%, Mn = 0,2 - 0,3%, Cr = 0,2 - 0,5%, W = 1,0 - 1,5%, P < 0,025%, S < 0,004%)
To be continued.......