STUDY ON FABRICATION, MICROSTRUCTURE AND PROPERTIES OF IN SITU TiC PARTICLE ON DISPERSION--STRENGTHENED 304 STAINLESS STEEL

TiC dispersion-strengthened 304 stainless steel was fabricated using the technique of in situ reaction during melting of the steel.Microstructure observation reveals that the distribution of the added TiC particles with the size of 3—10μm is basically uniform in the matrix grains,but slight aggregation of particles is observed in a few areas in the microstructure.The addition of TiC particles into 304 stainless steel results in the increase of ultimate strength,but the decrease of ductility.When the ingot of the TiC dispersion strengthened 304 stainless steel prepared is remelted by the technique of electroslag remelting,TiC particles in the steel are significantly refined and the distribution of them becomes more homogeneous,therefore the tensile properties of the steel are further improved in comparison with that before electroslag remelting.Some tiny TiC particles with nano-scale were observed in the microstructure of the steel after electroslag remelting.Introduction of TiC particles to 304 stainless steel also causes a notable increase in creep resistance at the temperature of 650℃and applied stress of 150 MPa and the further improvement on creep properties of the steel is obtained after electroslag remelting.