A maraging heat-treatment steel includes 8.5 to 9.5% by weight of Cr, 0.15 to 0.25% by weight of Mn, 2 to 2.7% by weight of Ni, 0.5 to 2.5% by weight of Mo, 0.4 to 0.8% by weight of V, 0.001 to 0.15% by weight of Si, 0.06 to 0.1% by weight of C, 0.11 to 0.15% by weight of N, 0.02 to 0.04% by weight of Nb, maximum 0.007% by weight of P, maximum 0.005% by weight of S, maximum 0.01% by weight of Al, iron and standard impurities, wherein a weight ratio of vanadium to nitrogen V/N is in a range between 4.3 and 5.5.