Page 11 - Steel Tech India eMagazine Volume April 2022
P. 11

VOL. 16 • NO. 3 • April 2022
                 A Study on Ladle De-Phosphorization of Induction

                 Furnace Steel


                 B N Sen, Prasenjit Nag and Somnath Guha
                 Metalist Consultants Pvt Ltd, INDIA













                 INTRODUCTION                                       languages. (2)

                 the well known Iron Age can be termed as the flame   thereafter the steel making process has seen many
                 to ignite the industrial revolution of ancient age and in   technological advancements to reach current state
                 its own scale.                                     with continuous improvement in productivity, quality
                                                                    and cost and we have witnessed primary steel making
                 Iron production reportedly began in Anatolia around   processes like Bessemer, Open  hearth,  eAF,  lD
                 2000 Bc, and the Iron Age was well established by   (BOF)to name a few. Besides, these high productivity
                 1000 Bc.  the technology of iron making thereafter   furnaces globally,   in country like ours, another steel
                 spread widely and by 500 Bc it had reached the     making route has significant contribution to the overall
                 western limits of europe, and by 400 Bc it had reached   production and that  is Induction Melting furnaces
                 china. the basic raw material for Iron making, the Iron   which in current days produce nearly 30-35 % of the
                 ores are widely distributed over the world and the other   total steel output of the country.
                 raw material that was  charcoal at that age , was also
                 readily available from woods. the iron was produced   the next development was the process  of secondary
                 in small shaft furnaces as solid lumps, called blooms,   metallurgy and  the   lADle furnace steel making
                 and these were then hot forged into bars of wrought   emerged out  for treating the  base steel coming from
                 iron, a malleable material containing bits of slag and   primary furnaces, (IF Steel excluded though) were
                 charcoal. (1)                                      introduced in late fifties/ early sixties of the last century
                                                                    in first Sweden with  intention to vacuum treat the
                 Down to Asia Pacific, South of India can boast of being   steel and with integrated facility for reheating through
                 pioneer in iron making inthe region at ancient days.  3 phase electrode arcing.  that’s how the modern
                 The reputation of Woodtz steel of South India had its   practice for ladle metallurgy started and thereafter
                 own reputation and grewconsiderably in the rest of the   spread extensively over the world for its distinct
                 world.this kind of high carbon steel was made in bowl   advantages.  the critical  advantages extracted from
                 type  clay furnaces  using  mainly  magnetite  ore  and   ladle metallurgy process were not only  superior steel
                 charcoal. Large-scale Wootz steel production in India   quality with respect to cleanliness,  chemistry control,
                 using crucibles occurred by the sixth century Bc, the   lower sulphur and gas contents ,  reduced heat cycle
                 pioneering precursor to modern steel production and   time, reduced cost, long sequence casting etc. but
                 metallurgy.  Romans imported this technology to spread   also much  enhanced productivity at low capital cost,
                 the steelmaking process at europe.It has been claimed   circulating degassing as well. this secondary refining
                 that ‘Wootz’ is in fact a corruption of ‘ukku’, the word   process can be integrated with tank and Rh degassing.
                 for steel in many South Indian languages It has been   In  fact,  ladle  refining  process  converted  the  primary
                 claimed that ‘Wootz’ is in fact a corruption of ‘ukku’, the   steel making furnaces into a melting  and oxidising
                 word for steel in many South Indian languages
                                                                    process vessels and  to reduce carbon and phosphorus
                 It has been claimed that ‘Wootz’ is in fact a corruption   primarily and  heavily shortening the heat cycle time
                 of ‘ukku’, the word for steel in many South Indian   from the primary furnaces and the balance part of
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