Abstract
As a new technique, the Spray-Dispersion Method, which can produce a steel containing homogeneously dispersed fine oxide particles sprayed from outside into the molten steel stream, has been developed by the authors. Al2O3-or ZrO2-dispersed 18 chromium-8 nickel stainless steels containing 1 at% niobium were produced by this method, and the distribution of oxide particles and the mechanical properties of the stainless steels were studied.
The homogeneous distribution of fine oxide particles was obtained for 18 chromium-8 nickel stainless steel. Because of fine dispersed particles, the strength of steels increased with their volume fraction; for example, 2.12 vol%ZrO2 caused an increment of 74 MPa in proof strength and 78 MPa in tensile strength, and those increments were maintained even at 973 K. Furthermore fine oxide particles contributed to the increase of creep rupture strength, and this tendency became more pronounced at the longer rupture time side. As a result, the production of oxide dispersion strengthened stainless steel has been established by the Spray-Dispersion Method.
