Completely martensitic steel alloy

摘要

A novel fully martensitic hardenable steel has the composition (by wt.) 8-15% Cr, up to 15% Co, up to 4% Mn, up to 4% Ni, up to 8% Mo, up to 6% W, 0.5-1.5% V, up to 0.15% Nb, up to 0.04% Ti, up to 0.4% Ta, up to 0.02% Zr, up to 0.02% Hf, NOTGREATER 50 ppm B, up to 0.1% C, 0.12-0.25% N, balance Fe and impurities, the sum of Mn + Ni being less than 4% and the sum of Mo + W being less than 8%. Also claimed is a heat treatment process for the above steel, comprising solution annealing at 1150-1250 degrees C for 0.5-15 hrs., cooling to room temperature and then tempering at 600-820 degrees C for 0.5-25 hrs.