X2CrNbZr17 or 1.4590
C: 0.030% max Si: 1.00% max Mn: 1.00% max P: 0.040% max S: 0.015% max Cr: 16.0%-17.5% Nb: 0.35%-0.55% Zr: 7×(C+N) +0.15% min