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Lanjewar H.A.,JSW Steel Ltd | Tripathi P.,JSW Steel Ltd
Journal of Materials Engineering and Performance | Year: 2016

Strengthening mechanisms dominant in non-equiaxed ferrite structures are not so familiar and well measured. In present study, non-equiaxed ferritic structures were generated and perceived to be strengthened by grain/crystal refinement, presence of varying substructures, solid solution strengthening, and textural hardening. A Nb-V microalloyed steel was modeled under various accelerated cooling and coiling temperature conditions in a thermo-mechanical simulator. Decrease in coiling temperature in conjunction with accelerated cooling resulted in non-equiaxed ferrite structures with array of phase morphologies. Intermediate transformation conditions produced increase in strength concurrent with observed smallness in crystallite size and high amount of microstrain in the matrix phase indicative of high dislocation densities and crystal imperfections. Increase in strength is partially attributed to solid solution and texture hardening owing to increase in (111) pole intensity in structure. © 2016 ASM International


Nagashanmugam K.B.,JSW Steel Ltd | Srinivasan K.,Anna University
Indian Journal of Chemical Technology | Year: 2011

An activated carbon has been prepared from gingelly oil cake (GOC) by zinc chloride treatment and its Cr(VI) removal capacity is compared with that of commercial activated carbon (CAC). The effect of experimental parameters such as pH, initial concentration, contact time and adsorbents dose for Cr(VI) removal has been studied. Langmuir, Freundlich and Temkin models are tested to describe the equilibrium isotherms. The maximum adsorption capacity of the adsorbents calculated from Langmuir isotherm is found to be 62.5 mg/g and 25.13 mg/g for zinc chloride treated gingelly oil cake carbon (ZTGOC) and CAC respectively. R2 values show that both Langmuir and Freundlich models fit well to explain the adsorption phenomenon for ZTGOC and CAC. The kinetic data fits best to pseudo-second order model. FT-IR analysis has been used to obtain information on the nature of possible interaction between carbon adsorbents and metal ions. SEM images confirm the adsorption of Cr(VI) onto these adsorbents through morphological observations. Thermodynamic study shows the feasibility of process and spontaneous nature of the adsorption. The carbon adsorbents have also been tested for the removal of Cr(VI) from chrome plating wastewater and are found to remove Cr(VI) effectively.


Nagashanmugama K.B.,JSW Steel Ltd | Srinivasanb K.,Anna University
Indian Journal of Chemical Technology | Year: 2011

An activated carbon is prepared from gingelly oil cake (GOC) by using sulphuric acid treatment and its Cr(VI) removal capacity is compared with that of commercial activated carbon (CAC). The effect of experimental parameters such as pH, initial concentration, contact time and adsorbents dose for Cr(VI) removal are studied. Langmuir, Freundlich and Temkin models are tested to describe the equilibrium isotherms. The maximum adsorption capacity of the adsorbents calculated from Langmuir isotherm is found to be 30.58 mg/g and 25.13 mg/g for sulphuric acid treated gingelly oil cake carbon (STGOC) and CAC respectively. R2 values show that both Langmuir and Freundlich models fit well to explain the adsorption phenomenon for STGOC and CAC. The kinetic data fits best to pseudo second-order model. FTIR analysis is used to obtain information on the nature of possible interaction between adsorbents and metal ions. SEM images confirmed the adsorption of Cr(VI) onto these adsorbents through morphological observations. Gibbs free energy values showed the feasibility of process and spontaneous nature of the adsorption. The adsorbents are also tested for the removal of Cr(VI) from chrome plating wastewater and found to remove Cr(VI) effectively.


Barman S.C.,ArcelorMittal | Mrunmaya K.P.,JSW Steel Ltd | Ranjan M.,JSW Steel Ltd
Journal of Iron and Steel Research International | Year: 2011

Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process, it has not yet been established and optimized. Thus, a mathematical model was developed to determine various raceway parameters such as RAFT (raceway adiabatic flame temperature), tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry, zone temperature and kinetic energy accumulated in tuyere gas. Besides, all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas, which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal. © 2011 Central Iron and Steel Research Institute.


Sah R.,JSW Steel Ltd. | Dutta S.K.,M. S. University of Baroda
Transactions of the Indian Institute of Metals | Year: 2011

An attempt has been made to study the effect of coal quality on the reduction kinetics of iron ore-coal composite pellets under non-isothermal condition in inert atmosphere. During non-isothermal reduction of composite pellets, it is observed that (i) reduction rate of iron oxide increases with increasing temperature, (ii) reduction rate increases with increase in porosity of pellets and (iii) the computed values of activation energy (E) are lower during the initial stage of reduction (0.86-8.82 kJ mol -1) than those in the later stages of reduction (12.37-38.32 kJ mol -1). These values indicate that the initial stage reduction is controlled by gaseous diffusion mechanism and at final stage, mixed control reaction mechanism (i.e., both gaseous-diffusion and chemical reaction) is the rate controlling step. The present investigation aims at to assess the effect of Fe tot/C fix ratio in pellet, volatile matter in coal, and temperature on the reduction kinetics of iron ore-coal composite pellets using simultaneous thermogravimetric and differential thermal analyser (TG-DTA). © 2011 Indian Institute of Metals.


Prachethan Kumar P.,JSW Steel Ltd | Raju B.S.L.,JSW Steel Ltd | Ranjan M.,JSW Steel Ltd
Ironmaking and Steelmaking | Year: 2011

The Corex smelting reduction process was developed as an alternative to the blast furnace and consists of two reactors: the reduction shaft and the melter gasifier. Coal rather than coke is used for heat generation, production of reducing gases and to maintain adequate bed permeability; hence, coals have to meet certain physical, chemical and especially high temperature properties for stable process operation and high iron outputs. Statistical analysis was employed to investigate the influence of coal properties on Corex performance, and laboratory coal characterisation studies were correlated with plant performance. This paper details these coal characteristic studies and highlights the coal blend properties required for superior plant performance. © 2011 Institute of Materials, Minerals and Mining.


Umadevi T.,JSW Steel Ltd | Brahmacharyulu A.,JSW Steel Ltd | Sah R.,JSW Steel Ltd | Mahapatra P.C.,JSW Steel Ltd
Ironmaking and Steelmaking | Year: 2014

From a sinter production point of view, it is important to optimise the sintering process with regard to both sinter quality and production rate. In sintering, airflow rate within the sinter bed decides the production rate and its physical and metallurgical properties. To study the influence of airflow rate (flame front speed) on sinter production and sinter quality, pot grate sintering experiments were conducted at sinter grate suction pressures ranging from 900 to 1700 mm water column over the sinter bed. During sintering, time-temperature data were recorded, and mineralogical studies were carried out. This study reveals that increase in sinter grate suction pressure through the sinter bed from 900 to 1700 mm water column significantly improved the sinter productivity from 34.37 to 48.90 t/m2/day; however, the physical and metallurgical properties of the sinter at higher suction pressure were not optimum with respect to blast furnace requirements. The maximum sinter productivity with desired physical and metallurgical properties was obtained at suction pressure 1300 mm water column. At this pressure, improvement in sinter quality was due to optimum firing temperature and enough retention time available for formation of mineral phases. At an airflow rate 1300 mm water column, sinter productivity was 41.0 t/m2/day, sinter strength (TI) was 73.10%, reduction degradation index was 25.0 and reducibility was 71.50%. © 2014 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.


Ravichandar D.,JSW Steel Ltd | Balusamy T.,Anna University | Nagashanmugam K.B.,JSW Steel Ltd
Applied Mechanics and Materials | Year: 2014

JSW Steel Limited, Salem Works (JSWSL), is an integrated steel plant, having a production capacity of 1.0 mtpa (million tons per annum) of high-grade automotive special steels. At JSWSL, hydrogen induced cracks and center unsoundness contribute more to UT (Ultrasonic testing) rejections in chrome-molybdenum (Cr-Mo) and high manganese grade steels. Hydrogen induced cracks was controlled by increasing argon flow rate from 3-4 Nm3 to 7-9 Nm3 during vacuum degassing. Vigorous purging led to a reduction in hydrogen levels from around 2 ppm (parts per million) to less than 1.5 ppm. Center unsoundness was controlled through optimising superheats in tundish. Data of trial heats revealed that, UT rejections were more in heats cast with superheat levels more than 35°C. Based on the data obtained from trial heats superheat was optimised to 25-35°C for both Cr-Mo and high manganese steels. The present paper discusses the measures taken to reduce UT rejections in these grades. © (2014) Trans Tech Publications, Switzerland.


Umadevi T.,JSW Steel Ltd | Sah R.,JSW Steel Ltd | Mahapatra P.C.,JSW Steel Ltd
Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy | Year: 2014

Iron ore sinter, constituting a major proportion of blast furnace burden, significantly impacts the blast furnace performance. The chemical composition of iron ore fines, particularly alumina, sinter basicity and sinter MgO together with the thermal conditions that sinter blends are subjected to play an important role in the formation of mineral phases in sinter. To increase the sinter proportion (70-80%) in blast furnace, lowering of CaO in sinter mix is a vital parameter to balance the flux supply without affecting the slag volume and productivity. At present, the alumina content in the sinter grade iron ore fines at JSW Steel varies from 4 to 6%. The quality of iron ore presently being used calls for extensive investigations to produce low basicity sinter with high alumina iron ore. Studies have been carried out on low and high alumina iron ore fines to know the influence of sinter basicity and fuel (coke breeze) addition on sinter mineralogy, properties and productivity. It is found that with increase in sinter basicity, sinter productivity and reduction degradation index (RDI) decreased and tumbler index (TI) increased for both low and high alumina sinter at coke breeze rate of 65 kg t-1 of sinter. The low alumina sinter showed higher productivity and strength, and lower RDI due to the presence of higher silico ferrites of calcium and aluminium (SFCA) and magnetite phase, and lower pore phase as compared to high alumina iron ore sinter. The sinter productivity decreased and physical and metallurgical properties improved with increase in coke breeze addition by increasing the sinter basicity for high alumina sinter. © 2014 Institute of Materials, Minerals and Mining and The AusIMM.


Peranandhanthan M.,Indian Institute of Technology Kanpur | Peranandhanthan M.,JSW Steel Ltd | Mazumdar D.,Indian Institute of Technology Kanpur
ISIJ International | Year: 2010

Slag eye area in an axi-symmetrical water model of an argon stirred ladle has been measured through video photography as a function of gas flow rates, liquid depth, slag layer thickness and different types of upper phase liquid. It is shown that in addition to the principal operating parameters (i.e., gas flow rate, liquid depth and amount of slag), physical properties of the overlying liquid, particularly kinematic viscosity and density exert considerable influence on slag eye formation. Based on our experimental observation, it is shown that existing correlations do not constitute a sufficiently reliable basis for prediction of slag eye area in steelmaking ladles. Accordingly, a new correlation for slag eye area has been formulated through dimensional analysis embodying a large set of experimental data, derived from different combinations of bulk and upper phase liquids. Polynomial regression indicates that dimensionless slag eye area can be expressed in terms of Froude number, (Up 2/gH), density ratio, [RL/Δρ), and Reynolds number, (HUp/vs), via: (Aes/hH)=3.25(U P2/gH)1.28(ρL/Δρ) 055(νs/HUP)-005 in which, A es is the eye area, H is the slag layer thickness, h is the bulk liquid depth and UP is the average plume rise velocity. Experimental data reported by many investigators on aqueous as well as industrial scale ladle gas stirred ladles systems were subsequently applied to demonstrate the adequacy and appropriateness of the proposed correlation. Possible extrapolation of the correlation to eccentric gas injection and melt covered with a thick slag layer, which are more typical of ladle metallurgy steelmaking, is also examined. © 2010 ISIJ.

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