فهرست مطالب

Iron and steel society of Iran - Volume:3 Issue: 2, Summer and Autumn 2006

International Journal of iron and steel society of Iran
Volume:3 Issue: 2, Summer and Autumn 2006

  • 46 صفحه،
  • تاریخ انتشار: 1386/10/20
  • تعداد عناوین: 6
|
  • M.R.Toroghinejad, Gh.Dini Page 1
    A low carbon Al-killed Ti-added steel was produced in Mobarakeh Steel Complex in Iran. Mechanical properties and microstructural characterizations of steel in the as-cast, hot-rolled, cold-rolled and annealed conditions are presented. Dilatometery tests were carried out to measure the finishing and annealing temperatures of steel. It was found that the ad dition o f small amo unts of Ti increased the transformation temperatures. In addition, microalloying with titanium improved the ductility of the produced slabs and hot rolled steel sheet. However, low temperature annealing of Ti-added cold-rolled steel sheets led to a decrease in ductility. The results indicate that the full softening of the Ti-added cold-rolled steel is co mpleted for an annealing time of 2hr at 800èC.
  • M.Alizadeh, H.Edris, A.Shafyei Page 7
    Heat transfer mechanisms and the solidification process are simulated for a continuous casting machine and the geometric shape of the liquid pool is predicted considering different conditions. A heat transfer and solidification mo del is described for the continuo us casting of steel slabs. The mod el has been established on the basis of the technical conditions of the slab caster in the continuous casting unit of Mobarakeh Steel Company. This model involves a two-dimensional (2-D) transient energy equation. The governing equation was solved using the finite- volume procedure. The boundary conditions of the mold, water spray cooling, and air cooling regions have been defined. The mathematical model is able to predict the shell thickness, temp erature distribution in he mold and hell, and the interfacial gap between shell and mold. The modeling results were verified by the measured slab urface temperatures and a reasonable greement was achieved.
  • A.Mahdavian, A.Shafyei, E.Keshavarz Alamdari, D.F.Haghshenas Page 17
    In this Study, vanadium recovery from the steelmaking converter slag was studied. Salt roasting-basic leaching is the process which was applied to separate and extract vanadium from steel making slag. Ground slag was roasted after mix ing with determined quantities of sodium carbonate. The effect of time and temperature of roasting and sodium carbonate content were studied. The optimum temperature, time and sod ium carbonate content in the roasting p rocess were found to be 1000oC, 45 min and 10%, respectively. Temperature, time, leachant concentration and particle size were optimized for leaching process. It was determined that sodium carbonate is the major leaching agent in comparison with sodium hydroxide. The most suitable conditions fo r leaching process was found to be 80oC, 60 min, sodium carbonate to sodium hydroxide mass ratio of 40-50:10 and particle size between 100 and 120 mesh. More than 80% of vanadium was recovered under optimum conditio ns.
  • S.Ahmadi, S.M.M.Hadavi, A.Shokuhfar Page 22
    In the present work, deoxidation and refining of 316LVM steel (Lo w carbon Vacuum Melted) during the vacuum induction melting process was studied. This grade of stainless steel is one of the most important materials in medical applicatio ns. Vacuum deoxidation by carbon is the first stage of 316LVM stainless steel production process. In this stage, aluminum must be absent to avo id killing the C-O reaction. Deo xidation product in the VIM process is in gaseous state which is tapped by vacuum pump system. For this reason, vacuum deoxidation by carbon is the best method for refining 316LVM steel. Vacuu m induction melting has no significant effects on reduction of sulfur and phosphorus. After d eoxidation in vacuu m by carbon, addition of Al+Ca/Si is the best way for reducing the oxygen and increasing the steel cleanness.
  • A.M.Homayoun, M.Shahmohammadi, M.Soltanieh, A.Afzali Page 29
    USD 7 is o ne of the steel products of Isfahan Iron Melting Co mplex. It is cast in continuous casting moulds and rolled up to a rod of 5 mm diameter. Finally, it is wire drawn up to 3 mm and used as welding electrodes. This steel contains 0.05 to 0.09 wt. % carbon. The acceptable limit of the aluminium in this class of steel is less than 0.003 wt%. Therefore, it is categorized as rimmed steel. During forming process, there are some defects such as tearing and laminating that stop the forming process.The aim o f this research is to evaluate the factors causing the aforementioned defects. It was found that there were many porosities in the cast ingot. The area around these porosities was analyzed with EDS method, and inclusio ns with MnO and (Fe, Mn)O chemical composition were observed. It was found that they were external inclusio ns (slag inclusions caused by reoxidation and entrapment phenomena). Because of the presence o f these inclusio ns, these porosities are not welded together during rolling process. Therefore, in the next step s of the forming p rocess, these defects are revealed
  • M.H.Amin, A.Kazemzadeh, B.Arfaei, N.Saha, Chaudhury, V.Sahajwalla Page 34
    In this study, slag penetration into a magnesia refractory mo nolithic was investigated b y the crucible test method. A synthetic calcium aluminate slag system has b een used to study commercial magnesia mix refractory for 1, 2, 3, 4, 5 and 6 hours at 1450°C and 1600 °C. It has been shown that the penetration rate is co ntrolled by a diffusion mechanism at 1450°C. In this case, capillaries are the main channels of initial slag penetration into the refractory. In the penetration process of the slag system, calcium silicate was formed on the surfaces of MgO grains at 1450°C and around them by reaction between grain boundary and mayenite, as a main phase of slag with a low melting point. Dissolution of the refractory components in the slag could be supported by the penetration process at 1600°C. In this case, dissolutio n of the refractory components in the slag not only makes new open channels, but also changes the local slag composition, resulting in an increase in surface tension and viscosity of the slag.