This might help, did some cross referencing for you. Seems like it is comparable to AISI O2.
YK30
C:*1.05; Cr:*0.50; Mn:*1.00;*
Ni:*0.25; P:*0.03; S:*?;*
Si:*0.40;*
Maker: Daido - Japan (JP)
Notes:
By Japanese listings, YK30 is JIS SKS93 steel, however, Daido also lists it as AISI O2 steel. CRKT uses Daido YK30 in some of their knives.
Cross-References:
Standard:
JIS - SKS93
Proprietary:
Aichi - SK301
Hitachi - YCS3
NKK - NKG93
Nachi Fujikoshi - SK3M
Nippon Koshuha - K3M
Sanyo - QK3M
SK93
C:*1.00-1.10; Cr:*0.20-0.60; Mn:*0.80-1.10;*
P:*0.030; S:*0.030; Si:*0.50;*
Standard: JIS (Japan)
Notes:
Low alloy steel, for shear knives and dies. Similar to AISI O2 tool steel, however thereis no Vanadium in the specification.
Cross-References:
Proprietary:
Aichi - SK301
Daido - YK30
Hitachi - YCS3
NKK - NKG93
Nachi Fujikoshi - SK3M
Nippon Koshuha - K3M
Sanyo - QK3M
AISI O2
C:*0.85-0.95; V:*0.30; Cr:*0.35;*
Mo:*0.30; Mn:*1.40-1.80; Ni:*0.30;*
P:*0.03; S:*0.03; Si:*0.50;*
Cu:*0.25;*
Standard: AISI (US)
Notes:
Oil hardening tool steel. Working hardness up to 63-65HRC. Makes pretty decent performer for light/medium use knives at that hardness.
How it performs in real world scenarios, I don't particularly know. Though you should atleast have a ballpark now.