M2 cryo?

butcher_block

butcher_block

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Dec 6, 2004
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so i have some M2 and crucible doesnt say anything about cryo but since its so high alloy i thought maybe it should

so i need to know if i should wait till i refill my Ln or go ahead and heat treat it
i also have some 10 v that will be run at the high temp and i see some makers cryo it and some dont (last blade i did in 10v i did cryo)
so what say you guys
 
Since the tempering temperatures are so high ,~ 1100 F ,that eliminates retained austenite and cryo won't be any benefit. I never had an M2 knife so I don't know if there are really benefits.
 
You can get more toughness out of M2 if you use a low temper, and in that case you would use cryo.
 
Um....no. The upper temper can actually give you greater hardness, but the upper temper precipitates carbides which reduce toughness, even at the same hardness. If it were me, I would temper at 400F, which isn't the peak toughness (more like 700F), but should give a high hardness (at least 62 Rc), and greater toughness than an upper temper. M2 has a lot of possibilities for heat treatment.
 
ok jsut never heard of M2 haveing 2 temper ranges (all the tool makers must run it hot just cause the tool will see higher temps in use)
i have heard of may other steels haveig them tho
the blades im working on are "different" to say the least (ones a last ditch knife )
 
Tempering below 1000F is usually not recommended for high speed steels like M2
 
In normal use the high temperature tempering is used to develop secondary hardening. While this is important for tooling it has no importance for knives so either temperature range can be used.
 
Depending on the heat treat details, M2 might have as much as 30% retained austenite on quenching. That seems like asking for trouble to leave in the knife, since bending, even locally at the edges, could lead to transformation to untempered martensite. By the way, mete, a metallurgist in NYS? Where? Small world!
 
ejt, retired in Sullivan Co.I don't recommend things like M2 because knife use is far from it's typical use and HT requires some understanding of the steel.
 
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