Piston rings in cast tool steels and process for the manufacture thereof

2A piston ring in cast tool steels including a ring of a tempered material having a chemical composition including a percent weight concentration of C from 0.80 to 1.40, Cr from 2.50 to 4.20, Mn from 0.10 to 1.00, Mo from 1.00 to 2.00, Nb from 2.50 to 4.50, P of no more than 0.05, S of no more than 0.05, Si from 0.10 to 1.00, Ti from 0.10 to 0.30, V from 1.00 to 3.00, W from 1.00 to 3.00, and a remaining concentration balance of Fe. The tempered material may have a microstructure including a matrix of tempered martensite with precipitation of at least one of secondary MC carbides and MC carbides, M being at least one of V, Mo, Cr, and W. The microstructure may include NbC eutectic carbides having a cubic morphology. The tempered material may have a hardness from approximately 400 HV to 800 HV.