Basic Research Of Application Of 3D Printing Technology In Metallurgical High Temperature Functional Devices

The localization of high-quality steel is an important issue affecting the overall level of China’s metallurgy industry.In addition,as a highly polluting industry,metallurgy has an urgent demand for cleaner production technology in the metallurgical process with the continuous enhancement of people’s awareness of environmental protection and the guidance of national policies in recent years.Effectively removing inclusions in steel is a way to improve the quality of steel.The filtration method uses a porous filter to remove small-size inclusions that are difficult to be removed by other methods through mechanical interception,adsorption or rectification.NOx is the main air pollutant produced by the metallurgical industry.At present,the effective way to remove it is to load the catalyst on the porous carrier to reduce NOx.High quality porous high temperature functional device are required whether porous filters are used to remove inclusions in molten metals or porous catalyst carriers are used to reduce NOx.At present,the high temperature functional device prepared by traditional methods have some problems,such as single through-hole direction and small contact area with fluid in porous refractories prepared by extrusion method,uneven pore size and pore closure in impregnation method.To solve the above problems,this paper uses 3D printing technology to prepare molten metal filter and flue gas denitration catalyst carrier to improve the functionality and rationality of porous refractory products.According to its application environment,the material selection of porous products is optimized.Firstly,in the service environment of catalyst carrier,mullite material with excellent chemical corrosion resistance and thermal shock resistance is selected to prepare 3D printing flue gas denitration catalyst carrier.In the preparation stage of printing slurry,the effects of slurry preparation and printing parameters on 3D printing effect are studied.By adding three groups of different additives to the printing slurry,the high-temperature reaction or fiber pull-out and bridging traction mechanism are used to realize the lightweight of filter carrier and improve its mechanical strength and thermal shock resistance.In the structure,the V-shaped catalyst carrier is adopted to prolong the distance of flue gas passing through the aperture,so as to prolong the contact time between gas and catalyst,and increase the contact area between gas and catalyst carrier.So as to improve the no conversion.At18000h^-1,the NOx conversion rate of V-shaped catalyst support is about 5%higher than that of commercial mullite honeycomb ceramics.Secondly,for 3D printing molten metal filter,IF steel is taken as the research object.Aiming at the two main inclusions of Al₂O₃ and Al₂Ti O₅ in the molten steel of IF steel in the tundish and the complex environment in the tundish,magnesia alumina spinel material with high melting point,good volume stability and excellent thermal shock resistance and can adsorb the above two main inclusions is selected to prepare 3D printing molten metal filter.The sintering behavior,mechanical properties at room temperature and thermal shock resistance of porous spinel under the corresponding heat treatment system were studied.Finally,symmetrical direct current and staggered shunt molten metal filters are designed.Through numerical simulation,the flow field and inclusion flow direction in tundish without filter and two kinds of filters with different structures are compared,the removal mechanism of inclusions in molten metal by filter is explored,and the influence of filter structure on inclusion removal is analyzed.In addition to the direct adsorption of inclusions,the staggered shunt filter can also optimize the tundish flow field and promote the collision,growth and absorption of inclusions by slag,so as to improve the inclusion removal rate,which is 15%higher than that without filter.