A2 vs O1 Steel, Brief Comparison
A2 steel is knows as air harden steel while O1 steel is oil harden steel. Here we briefly compare this two tool steel grades as follows. A2 tool steel belongs to A-Group in ASTM A681, which have high hardenability and may be hardened in air. O1 tool steel belongs to O-Group in A681 standard, which must be hardened by quenching in oil.