Ferro-Chrome

Ferro-Chrome Ferro-chrome (Fe-Cr) is an alloy comprised of iron (Fe) and chromium (Cr).  Besides Cr and Fe, it also contains varying amounts of carbon (C) and other elements such as silicon (Si), sulphur (S), and phosphorus (P). It is used primarily in the production of stainless steel. The ratio in which the two metals (Fe and Cr) are combined can vary, with the proportion of Cr ranging between 50 % and 70 %. Fe-Cr is frequently classified by the ratio of Cr to C it contains. The vast majority of Fe-Cr produced globally is the ‘charge chrome’. It has a lower Cr to C ratio and is most commonly produced for use in stainless steel production. The charge chrome grade was introduced to differentiate it from the conventional high carbon Fe-Cr (HC Fe-Cr). The second largest produced Fe-Cr ferro-alloy is the HC Fe-Cr which has a higher content of Cr than charge chrome and is being produced from higher grade of the chromite ore. Other grades of Fe-Cr are ‘medium carbon Fe-Cr’ (MC Fe-Cr) and ‘low carbon Fe-C’ (LC Fe-Cr). MC Fe-Cr is also known as intermediate carbon Fe-Cr and can contain upto 4 % of carbon. LC Fe-Cr typically has the Cr content of 60 % minimum with C content ranging from 0.03 % to 0.15 %.  However C content in LC Fe-Cr can be upto 1 %. In international trade, Fe-Cr is classified primarily according to its C content. The common categories of Fe-Cr used in international trade are as follows. Charge chrome with a base of 52 % Cr. HC Fe-Cr with C content ranging from 6 % to 8 %, base of 60 % Cr, and a maximum of 1.5 % Si. HC Fe-Cr with C content ranging from 6...

Production of Ferro-Silicon Jun27

Production of Ferro-Silicon...

Production of Ferro-Silicon Ferro-silicon (Fe-Si) is a ferro-alloy having iron (Fe) and silicon (Si) as its main elements. The ferro-alloy normally contains Si in the range of 15 % to 90 %. The usual Si contents in the Fe-Si available in the market are 15 %, 45 %, 65 %, 75 %, and 90 %. The remainder is Fe, with around 2 % of other elements like aluminum (Al) and calcium (Ca). Fe-Si is produced industrially by carbo-thermic reduction of silicon dioxide (SiO2) with carbon (C) in the presence of iron ore, scrap iron, mill scale, or other source of iron. The smelting of Fe-Si is a continuous process carried out in the electric submerged arc furnace (SAF) with the self-baking electrodes. Fe-Si (typical qualities 65%, 75% and 90% silicon) is mainly used during steelmaking and in foundries for the production of C steels, stainless steels as a deoxidizing agent and for the alloying of steel and cast iron. It is also used for the production of silicon steel also called electrical steel. During the production of cast iron, Fe-Si is also used for inoculation of the iron to accelerate graphitization. In arc welding Fe-Si can be found in some electrode coatings. The ideal reduction reaction during the production of Fe-Si silicon is SiO2+2C=Si+2CO. However the real reaction is quite complex due to the different temperature zones inside the SAF. The gas in the hottest zone has a high content of silicon mono oxide (SiO) which is required to be recovered in the outer charge layers if the recovery of Si is to be high. The recovery reactions occur in the outer charge layers where they heat the charge to a very high temperature. The outlet gas form the furnace contains SiO2 which can...

Production of Ferro- Manganese Jun19

Production of Ferro- Manganese...

Production of Ferro- Manganese Ferro-manganese (Fe-Mn) is an important additive used as a deoxidizer in the production of steel. It is a master alloy of iron (Fe) and manganese (Mn) with a minimum Mn content of 65 %, and maximum Mn content of 95 %. It is produced by heating a mixture of the oxides of Mn (MnO2) and iron (Fe2O3) with carbon (C) normally as coke or coal. Fe-Mn in a blast furnace (BF) with considerably higher Mn content than was possible earlier was first produced in 1872 by Lambert Von Pantz. The Fe-Mn produced had 37 % Mn instead of 12 % being obtained earlier. Metallurgical grade Mn ores having Mn content higher than 40 % are usually processed into suitable metallic ferro- alloy forms by pyro-metallurgical processes, which are very similar to the iron pyro-metallurgical processes. In its production process, a mixture of Mn ore, reductant (a form of C) and flux (CaO) are smelted at a temperature which is higher than 1200 deg C to enable reduction reactions and alloy formation. Standard grades of Fe-Mn can be produced either in a BF or in an electric submerged arc furnace (SAF). The electric SAF process, however, is far more flexible than the BF process, in that slags can be further processed to Si-Mn and refined Fe-Mn. The choice of process is also dependent on the relative price of electric power and coke. In a three-phase SAF, the electrodes are buried in the charge material. The raw materials are heated and the Mn oxides pre-reduced by hot carbon mono oxide (CO) gas form the reaction zones deeper in the furnace. The exothermic reactions contribute favourably to the heat required. Efficient production of HC Fe-Mn depends on the degree of pre-reduction which occurs...

Titanium in Steels

Titanium in Steels  Titanium (Ti) (atomic number 22 and atomic weight 47.90) has density of 4.52 gm/cc. Melting point of Ti is 1660 deg C and boiling point is 3287 deg C. Ti is a highly active element. It usually forms a stable oxide coating at room temperature on its surface, which limits further oxidation. The phase diagram of the Fe (iron)-Ti binary system is at Fig 1. Fig 1 Fe-Ti phase diagram Ti forms stable compounds with oxygen (O), carbon (C), nitrogen (N) and sulfur (S) at temperatures of steelmaking. It is sometimes used in steelmaking because of its property for fixing of these elements in order to reduce their harmful effects. Ti is also used for the purpose of grain refining in many steels. In many respects, functions of Ti are similar to the addition of both aluminum (Al) and niobium (Nb). Ti is more expensive than Al; hence it is rarely used as a deoxidizer.  The reactivity of Ti is similar to that of magnesium (Mg) and it can quite easily be set on fire. It burns with a bright white flame, which can be harmful to look at. Ferrotitanium powder is also flammable, with the powder having finer size and higher Ti content being more hazardous. Ti ores are mainly ilmenite (FeO.TiO2) and rutile (TiO2).  Addition agents Ti containing addition agents are Ti metal scrap, ferroalloys and master alloys. Ti metal scrap may be of commercial purity Ti. Ti metal scrap is of two types one with 6 % Al and 4 % vanadium (V) while the second with 6 % Al, 2 % tin (Sn), 4 % zirconium (Zr), and 2 % molybdenum (Mo). Sn is usually an unwanted element in steels. Since the melting point of Ti is...