90MCV8 (AFNOR designation, Wnr. 1.2842, DIN 90MnCrV8) is an oil-hardening cold-work tool steel and the direct European counterpart to AISI O2. Unlike the D-series high-chromium cold-work steels, which lean on 11-13% chromium to build a massive volume of primary carbides, 90MnCrV8 gets its hardness and wear resistance from high carbon (0.85-0.95%) and manganese (1.8-2.2%) instead, with only a modest chromium addition and a small vanadium content for grain refinement. That chemistry gives it much finer, more evenly distributed carbides than a D-series grade — less extreme abrasion resistance, but noticeably better toughness and more forgiving machining and grinding behavior.

As an oil-hardening grade, 90MnCrV8 offers good dimensional stability through hardening compared with water-hardening tool steels, while still being simpler and less expensive to process than the air-hardening D- or A-series. It hardens to a useful 58-62 HRC range and is a mainstay for cutting and punching tools, shear blades, thread-cutting rings and jaws, reamers, gauges, and other precision tooling where a fine, uniform grain structure and good dimensional control through hardening matter as much as wear resistance.

In the annealed condition 90MnCrV8 machines noticeably easier than a high-chromium cold-work grade like D2 or D3, since it lacks the large volume of hard, coarse chromium carbides that make those steels so abrasive. The fine, well-distributed carbide structure here means more predictable, more consistent tool wear — cutting forces are elevated compared with a plain low-alloy steel due to the high carbon and manganese content, but the material doesn't chew through edges the way a carbide-heavy D-series grade does.

Chip formation is generally favorable in the annealed state, producing manageable segmented chips with a properly matched chipbreaker. As with most tool steels, the bulk of machining happens before hardening; only finishing, grinding, and light stock removal occur after the oil-quench-and-temper cycle brings the material up to its working 58-62 HRC hardness.

A coated carbide grade with good wear resistance and edge toughness handles this steel well across the annealed-to-lightly-hardened range most shops encounter. Rigid workholding and steady feed engagement help avoid the edge chipping that can occur if the tool is allowed to rub rather than cut cleanly, particularly as manganese content promotes some work hardening under a dull edge.