O2 is very similar to O1 in that its an excellent tool steel for general use and it's relatively inexpensive and fairly easy to machine. O2 is an oil hardened tool steel supplied in the annealed condition. O2 others all characteristics synonymous with tool steels, a decent level of durability as well as wear resistance.
It's a very viable substitute in place of more expensive tool steels were the extra utility would not be necessary. O2 forgoes the marginal corrosion resistance of D series steels, as well as some level of wear resistance. O2 has no tungsten when compared to O1 while its a fairly small amount it does aid the wear resistance.
AISI ASTM A681
BS EN ISO 4957