New iron-based alloy structure

A steel material whose constituent grains comprise a matrix in which precipitates are incorporated, the steel material comprising:

• i) the following elements as a percentage by mass of a total mass:
• 16% to 20% chromium,
• 8% to 14% nickel,
• 0.001% to 0.030% carbon,
• 0.001% to 0.050% oxygen,
• 0% to 2% manganese,
• 0% to 3% molybdenum,
• 0% to 1% silicon,
• wherein the remainder of the total mass is iron;
• ii) marks associated with a morphology of oval molten baths with a depth of less than 100 μm present within the steel material or in the matrix;
• iii) precipitates comprising spherical precipitates with an average size of between 10 nm and 150 nm, the spherical precipitates identified as being oxides of Mn and Si, in connection with the rapid solidification of the material, the precipitates further comprising at least one metal element chosen from a metal element M, a metal element M′, a metal element M″ or mixtures thereof;
• wherein M, M′ and M″ are selected independently from yttrium, titanium, iron, chromium, tungsten, silicon, zirconium, thorium, magnesium, manganese, aluminum, hafnium and molybdenum, or mixtures thereof;
• and
• iv) non-columnar grains of equiaxed morphology with an average size less than 40 μm;
• wherein:
• a distribution of grain boundaries on a surface of the steel material comprises 74.2% of highly disoriented boundaries >10° (called HAGB), 8.6% of weakly disoriented boundaries between 2° and 10° (called LAGB), and 17.2% of macular boundaries;
• the non-columnar grains comprise sub-micrometric cells, the sub-micrometric cells having an average diameter of less than 1 μm, and wherein a cell structure of the sub-micrometric cells comprises an internal nanometric cell substructure whose cells have an average diameter of less than 100 nm and are organized in a regular manner uniformly covering the matrix of sub-micrometric cells;
• and
• the spherical precipitates comprise an average size of between 1 nm and 10 nm, distributed primarily along walls of a substructure of the internal nanometric cell, the spherical precipitates comprising an average surface density of 40 precipitates per μm2.