3482

3288

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1385

چهارده ، 109 ،[II] ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

احمد منشي

26/2/86

رضا مظفري نيا، رحمت الله عمادي

1396/02/26

كتابنامه

مواد

مهندسي مواد

ID3288

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractPresent study concerns the chemical reactions involved and the phases formed duringpenetration of slags of variable composition into porous structure of tundish plaster Plastersused in the industry are composed of high MgO content and some additives and the tundishslag used in this study contained oxides of SiO2 CaO MgO Al2O3 MnO and some minorvariations of Fe FeO and TiO2 XRD and SEM studies indicated that when slag penetrated into pores of plaster developed thephases of Monticellite CaMgSiO4 Merwinite Ca3Mg SiO4 2 and Tephorite Mn2SiO4 around MgO particles with low melting points of 1498 C 1575 C and 1345 C respectively Dissolution of MgO particles by slag to develop these phases decrease the liquidustemperature of MgO from 2800 C to about 1500 C and provide deterioration of MgO layersof plaster Phase diagram of CaO SiO2 MgO indicates that decreasing SiO2 to below 20 and increasingCaO content to as high as possible increase the liquidus temperature to above 2000 C Sourceof SiO2 in the process are the rice husk addition which is used as an insulating material on topof the melt beside the tundish flux addition and possible slag coming from ladle furnace These sources should be reduced to as low level as possible This fact does not affect thefluidity of slag which is required for inclusion removal Fluidity of slag comes from lowmelting point eutectics in CaO Fe2O3 and CaO FeO about 1200 C due to iron oxide on topof the steel melt Replacing part of magnesia of plaster by chromite and olivine is another suggestion fordecreasing corrosion of common plaster because the base acid gap between the introducedplaster and the slag containing SiO2 decreases and causes the formation of phases with highmelting points such as Forsterite Mg2SiO4 in chromite magnesite plaster and Forsterite Mg2SiO4 with Calcium Silicate Ca2SiO4 in olivine magnesite plaster on the surface ofMgO grains and decrease the dissolution of plaster in the slag For kinetic consideration of MgO dissolution of tundish plaster in steel slag the differentmodels were compared It was found that it is not a diffusion controlled process and is affectedby turbulent flow of viscous steel slag Some modification of the power of time in thesemodels was carried out and the best kinetic equation for this complicated system wasproposed

احمد منشي

رضا مظفري نيا، رحمت الله عمادي