Method for producing semi-finished products from a nickel-based alloy

A method for the manufacture of semifinished products from a nickel-base alloy of the following composition (in mass %)

• Ni >50-<55%
• Cr >17-<21%
• Nb >4.8-<5.2%
• Mo >2.8-<3.3%
• Ti >0.8 to <1.15%
• Al >0.4 to <0.6%
• C max. 0.045%
• Co max. 1.0%
• Mn max. 0.35%
• Si max. 0.35%
• S max. 0.01%
• Cu max. 0.3%
• Fe the rest as well as unavoidable impurities,
• wherein the following elements are added as alloy constituents within the specified ranges:
• B 0.0001-0.01%
• P 0.0001-0.02%
• wherein, for production of precursor products, the alloy is melted and if necessary remelted, the precursor products are subjected to at least one hot forming, the precursor products are then subjected to a multi-stage annealing and aging treatment,
• wherein a solution-annealing treatment is undertaken in the temperature range between 1000 and 1100° C. for a period between 1 hour and 3 hours, the precursor products are cooled in air, water or oil, the precursor products are subjected to a two-stage precipitation hardening, namely in the temperature range of 650° C.-<770° C. at first for a period of 5 hours to 9 hours and then in the temperature range of 600° C.-650° C. for a period of 5 hours to 9 hours and the precursor products are cooled to room temperature,
• wherein the precursor products are subjected if necessary to at least one further heating, and
• wherein specimens of the precursor product are subjected to a corrosion test with low strain rate, wherein a reduction of area at break ratio Z≥0.57 is obtained during the use of an NaCl solution with additions of CO2 and H2S.