Effect Of Pre-dispersed Nano ZrO₂ Particles On The Microstructure And Properties Of Q235 Steel

Steel is a materials that used very wide,people continue to pursue the production of high strength,high toughness,high plasticity of the ideal steel material.By adding micro-nanoscale oxides to the steel is possible to increase the nucleation sites,refine the grains and thereby improve the properties of the steel.Because of the good controllability of the external addition,the particle selection range is wide and not limited by the steel type.Studying the dispersion of nanoparticles is a topic worth exploring.In this paper,the use of electromagnetic induction furnace manufacturing steel;The distribution of pre-dispersed nanosized zirconia and untreated nanosized zirconia in steel was compared by Field Emission scanning electron microscopy and XRD.By means of metallographic analysis,hardness test and tensile test compare Metallography,hardness and tensile strength about adding nano-zirconia to steel and non-adding nano-zirconia,adding pre-dispersion treatment and without pre-dispersion of nano-zirconia,adding 100 nm and 20 nm pre-dispersed zirconia steel sample microstructure,Experimental results show,the steel sample of adding the pre-dispersion treatment of nano-zirconium dioxide size of 100 nm than the adding of 20 nm nano-zirconium dioxide dispersion index were 0.94,0.91,so the pre-dispersed nano-zirconia particles can be uniformly dispersed in the steel.Compared with the steel without adding nano-zirconia,the grain size of the sample with nano-zirconium dioxide added was 9.44?m,the hardness increased by 6.5,the tensile strength increased by 10.9Mpa,the elongation increased by 0.73%.Adding pre-dispersed nano-zirconia than without pre-dispersed nano-zirconium dioxide sample grain refinement of 20.58?m,hardness increased by 12.8,the tensile strength increased by 13.9Mpa,the elongation increased by 8.35%.Compared with the steel sample with the nano-zirconium oxide pre-dispersed,the size of the nano-zirconium dioxide in the sample of 100 nm is refined to 8.21 ?m,the hardness is increased by 6.46,the tensile strength is increased by 20 MPa and the elongation is increased 0.5%.