Hp295 Steel Cerium In The Thermodynamic Calculation And Refine The Organization Effect Of The Titanium And Mechanism Research

"The oxide metallurgy" was received significant attention and researched by the academics of metallurgy and material after it was put forward.The structure can be refined through the use of dispersive and tiny oxide inclusions in promoting the formation of intragranular ferrite so as to improve the toughness of the steel.The research on "the oxide metallurgy "focused on the nucleation mechanism of promoting inclusions intragranular ferrite at home and abroad, and it was a lack of systematic study about the effect on formation of intragranular ferrite in the process.This article analysed the inclusion type existed in the HP295steel through the thermodynamic calculation. And it analysed the form of factors on the intragranular ferritic influence through the observation of inclusion in the morphology and distribution of size and the chemical composition. And it studied the influence of the different cooling rate on intragranular ferritic systematacially. And it discussed the nucleation mechanism of intragranular ferritic.Through the thermodynamic calculation, it analysed generative rule of the inclusions in the experimental system of liquid steel and solidification process before and after adding cerium and titanium. The results showed that the mainly inclusions were quartz (SiO2), manganese aluminum garnet (3MnO·Al2O3·3SiO2), mullite (3Al2O3·2SiO2) and corundum (Al2O3) before adding Ce/Ti complexing agent. After adding Ce/Ti the mainly inclusions were generate Ce2O3, Ce2O2S, CeAlO3and Ti2O3·Al2O3, etc.The chemical composition, morphology and size distribution of all kinds of inclusion was observed and studied by optical microscope and scanning electron microscope before and after adding Ce/Ti in the experiment system of steel. And the morphology of the electrolytic inclusion was observed and confirmed the type of oxide in steel. The results showed that the contains cerium oxide is Ce2O3in agreement with the thermodynamics of inclusions. In the experimental system, the results of the size and type of quantitative statistical analysis showed that the conclusion of Ce2O3are tiny and much in quantity in the materials content Ce0.2%and Ti0.03%.Through austenitizing in1200℃, grain size of austenitic was changed in the experimental steel. The influence was discusses toward the intragranular ferrite in different cooling system. The results showed that quench was most benefit to form intragranular ferrite, and the organization of intragranular ferrite was tiny and distributed intricately.Through the calculation of mismatch between inclusion and Fe, the conclusion showed that:the mismatch between CeS, CeO2, Ce2O3, Ce2O2S and α-Fe、δ-Fe less than8%, these high melting conclusions was benefit to accelerate the non-uniform nucleation of HP295in liquid steel. The minimum mismatch between the inclusions in liquid steel of CeS, CeO2with γ-Fe was45.8%which less than8%,so it was not conducive to promoting γ-Fe non-uniform nucleation.