@Marthinius
We are definitely hijacking this thread mate
I'll answer to this after then I'll call it a day.
Your own datasheet is quite old, preliminary and superseeded either by this datasheet http://www.danieleberti.com/dan/knives/bohler_m390de.pdf (which is the complete version from which I took HT). It is superseeded also by some research done by Institute of Metallurgy in Zurich, in Switzerland (already mentioned in this thread).
In this thread the great majority of knives tested are production blades and thus we are to focus on HT that is always Vacuum, not oil quenching, not cryo (Hogue HT of A2 has cryo if I'm not wrong), by no means secondary hardening (which is quite risky).
If you look at the link, there is a page and a picture where it is discussed about stain resistance, and the temps are quite clear. They mention 1150C/150C .
Now, as far as austenitizing temps are concerned, it is common knowledge that in highly alloyed steels you've to raise a little bit the temp with Vacuum HT, and this is confirmed by 1200°C as the max documented austenitizing temp for M390, against 1180°C of other media. That's why I mentioned 1180°C/150°C.
The secondary hardening temperature, with vacuum aust. is not 540°C but lower, see graph.
Neels Roos shares a lot about HT included quenching media and time here
http://www.sablade.com/forums/showthread.php?1385-M390-Tactical-and-heat-treating-experiment
BTW I purchased this knife
So CCT is practically treated here.
HT graphs are the ones I posted above
Anyway, as a rule of thumb, consider that Elmax has the best stain resistance when vacuum HTd is achieved at 1080°C/180°C (the lowest allowed tempering temp), thus 100°C less for austenitizing than M390. In M390 we find same Moly but 1% more Vanadium which should improve hardenability a little bit. Increase in aust. temp should thus be compensated at least to some extent by 1%more V and CCT graph should be quite like the same as Elmax own.
Finally.
My last posts, here I rejoice with this thread, and particularly the answers to your M390 questions have been written to outline than knowing HRC is pretty much informative when a certain steel makes part of a production blade. For sure you can reach the same hardness multiple times changin' aust and/or tempering, but it is just as acquired that in mass production it will be used the lowest furnace/owen temperature combination that for a given steel will give the same HRC value, as this will turn into a great money saving
Custom makers: recently I contacted an emerging one for a fixed Elmax knife. He told me his Elmax blades are vacuum hardened to 59HRC and when I asked him if he exploited deep cryo and/or secondary hardening he said yes to both.
I will NOT make his name, but it is self evident that with Elmax 1)Deep cryo adds nothing when SH is used 2)HRC should have been =60 to say the least.
HRC are important? Oh yes: they are. Are they the whole picture? Nope. But the whole picture can be reasonably unveiled using HRC value and some reasoning
We are definitely hijacking this thread mate
I'll answer to this after then I'll call it a day.Your own datasheet is quite old, preliminary and superseeded either by this datasheet http://www.danieleberti.com/dan/knives/bohler_m390de.pdf (which is the complete version from which I took HT). It is superseeded also by some research done by Institute of Metallurgy in Zurich, in Switzerland (already mentioned in this thread).
In this thread the great majority of knives tested are production blades and thus we are to focus on HT that is always Vacuum, not oil quenching, not cryo (Hogue HT of A2 has cryo if I'm not wrong), by no means secondary hardening (which is quite risky).
If you look at the link, there is a page and a picture where it is discussed about stain resistance, and the temps are quite clear. They mention 1150C/150C .
Now, as far as austenitizing temps are concerned, it is common knowledge that in highly alloyed steels you've to raise a little bit the temp with Vacuum HT, and this is confirmed by 1200°C as the max documented austenitizing temp for M390, against 1180°C of other media. That's why I mentioned 1180°C/150°C.
The secondary hardening temperature, with vacuum aust. is not 540°C but lower, see graph.
Neels Roos shares a lot about HT included quenching media and time here
http://www.sablade.com/forums/showthread.php?1385-M390-Tactical-and-heat-treating-experiment
BTW I purchased this knife
So CCT is practically treated here.
HT graphs are the ones I posted above
Anyway, as a rule of thumb, consider that Elmax has the best stain resistance when vacuum HTd is achieved at 1080°C/180°C (the lowest allowed tempering temp), thus 100°C less for austenitizing than M390. In M390 we find same Moly but 1% more Vanadium which should improve hardenability a little bit. Increase in aust. temp should thus be compensated at least to some extent by 1%more V and CCT graph should be quite like the same as Elmax own.
Finally.
My last posts, here I rejoice with this thread, and particularly the answers to your M390 questions have been written to outline than knowing HRC is pretty much informative when a certain steel makes part of a production blade. For sure you can reach the same hardness multiple times changin' aust and/or tempering, but it is just as acquired that in mass production it will be used the lowest furnace/owen temperature combination that for a given steel will give the same HRC value, as this will turn into a great money saving
Custom makers: recently I contacted an emerging one for a fixed Elmax knife. He told me his Elmax blades are vacuum hardened to 59HRC and when I asked him if he exploited deep cryo and/or secondary hardening he said yes to both.
I will NOT make his name, but it is self evident that with Elmax 1)Deep cryo adds nothing when SH is used 2)HRC should have been =60 to say the least.
HRC are important? Oh yes: they are. Are they the whole picture? Nope. But the whole picture can be reasonably unveiled using HRC value and some reasoning
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