Page 11 - Steel Tech India eMagazine Volume April 2022

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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