Page 38 - Steel Tech India eMagazine Volume October 2020

81. Ŗ 01 Ŗ 1EVQDGT

Table1: Metallurgical tasks per different secondary metallurgy units
Heating capability Sulphur Carbon Hydrogen Nitrogen
removal removal removal removal
Argon stirring station 0Q ;GU 0Q 0Q 0Q
.CFNG (WTPCEG ;GU ;GU 0Q 0Q 0Q
%JGOKECN JGCVKPI RTQEGUU ;GU ;GU 0Q 0Q 0Q
4* FGICUUKPI ;GU YKVJ VQR 0Q ;GU ;GU ;GU
oxygen lance
8CEWWO VCPM FGICUU KPI ;GU YKVJ VQR ;GU ;GU ;GU ;GU
oxygen lance
Ō 6QR UNCI RTCEVKEG CPF UVTQPI UVKTTKPI RTQEGUU Ō JKIJ VGORGTCVWTG NQUUGU
Ō .KOKVGF RTQEGUU Ō RQUUKDNG YKVJ OQFKſGF VQR UNCI CPF YKVJ UVTQPI NCPEG UVKTTKPI RTQEGUU
Ō 6TKCNU YKVJ OCVGTKCN KPLGEVKQP CPF QT YKVJ RTG HWUGF UNCI CRRNKECVKQP
Ō 2QUUKDNG YKVJ WNVTC NQY KPNGV 5WNRJWT EQPVGPV CPF FGRGPFKPI QP 4* XGUUGN NGCM TCVG COQWPV

Steel Quality Requirements: BOF versus EAF +P TGICTF VQ UVGGN SWCNKV[ VJG OCKP FKHHGTGPEG DGVYGGP
Steelmaking Philosophy VJG $1( CPF '#( RTQEGUUGU OC[ DG UWOOCTK\GF CU
+P TGEGPV [GCTU EWUVQOGTU JCXG UVGCFKN[ KPETGCUGF VJGKT HQNNQYU
TGSWKTGOGPVU HQT UVGGN SWCNKV[ NQYGT ECTDQP 5WNRJWT Ŗ 6JG $1( CEJKGXGU NQYGT PKVTQIGP EQPVGPV DGHQTG
PKVTQIGP CPF KPENWUKQP EQPVGPV VQIGVJGT YKVJ NGUU VCRRKPI EQORCTGF YKVJ '#( RTQEGUU
XCTKCVKQP KP UVGGN SWCNKV[ HTQO ECUV VQ ECUV +P 6CDNG T 7UWCNN[ PKVTQIGP EQPVGPV DGHQTG VCRRKPI KU
DGNQY KU TGRQTVGF V[RKECN OCZKOWO CNNQYGF KORWTKV[ CNKIPGF YKVJ OCZKOWO CNNQYGF EQPVGPV RGT
EQPVGPVU HQT XCTKQWU UVGGN ITCFGU ITCFG

Table 2: Typical steel cleanliness requirements (1) T 4GOQXCN QH UNKIJV SWCPVKVKGU QH PKVTQIGP EQWNF DG
TGSWKTGF FWTKPI VJG XCEWWO RTQEGUU
Steel product Maximum allowed content
Ŗ 6JG $1( CEJKGXGU NQYGT 5WNRJWT EQPVGPVU KP
(ppm); Inclusion side - D ECUG 5WNRJWT TGOQXCN HTQO JQV OGVCN KU PGEGUUCT[
+PVGTUVKVKCN HTGG ITCFGU =%? ŭ =0? ŭ Ò 6 1 RTKQT VQ VJG $1( RTQEGUU CPF FWG VQ NQYGT UETCR
ŭ EQPUWORVKQP EQORCTGF YKVJ '#( RTQEGUU
#WVQOQVKXG CPF FGGR =%? ŭ =0? ŭ & ŭ †O Ŗ 6JG $1( RTGUGPVU C UOCNNGT TCVKQ DGVYGGP (G1 KP
drawing grades UNCI XGTUWU ECTDQP EQPVGPV DGHQTG VCRRKPI
Drawn and ironed cans =%? ŭ =0? ŭ & ŭ †O
6 1 ŭ $GUV #XCKNCDNG 6GEJPKSWG GXCNWCVKQP TGSWKTGF VQ OCMG
Alloy steel bars =*? ŭ =0? Ò & ŭ †O RTQRGT FGEKUKQPU PGGFGF HQT C VTCPUK VKQP HTQO $1( VQ
6 1 ŭ '#( UJCNN KPENWFG UGEQPFCT[ OGVCNNWTI[ RTQEGUU CPF
GSWKROGPV GXCNWCVKQP CU YGNN YKVJ VJG CKO QH MGGRKPI
*+% TGUKUVCPV UVGGN =5? ŭ =2?ŭ VJG UCOG RTQFWEV OKZ CU VJG $1( DCUGF OGNV UJQR
Line pipe =5? ŭ Ò =0?ŭ Ò & CPF JCXKPI VJG RQUUKDKNKV[ QH KORTQXKPI UVGGN SWCNKV[ KP
ŭ †O 6 1 ŭ HWVWTG 6JCPMU VQ UVTQPI GZRGTKGPEG YKVJ OQTG VJCP
5JGGV HQT EQPVKPWQWU =0?ŭ Ò XCEWWO VCPM FGICUUKPI UVCVKQPU CTQWPF VJG YQTNF
annealing HQT FKHHGTGPV CRRNKECVKQPU KPENWFKPI ƀCV RTQFWEVKQP CPF
2NCVG HQT YGNFKPI =*?ŭ UVCKPNGUU UVGGN CU YGNN &CPKGNK JCU VJG RTQRGT UQNWVKQP
Ball bearings & ŭ †O 6 1 ŭ HQT HWN ſNNKPI SWCNKV[ TGSWKTGOGPVU YJGP QRGTCVKPI CP
Tire cord =*?ŭ =0?ŭ & ŭ Ò †O '#( CU VJG RTKOCT[ OGNVKPI WPKV (KIWTG RTGUGPVU
6 1 ŭ &CPKGNKŏU GZRGTKGPEG YKVJ VJG XCEWWO VCPM FGICUUKPI
0QP ITCKP QTKGPVGF =0?ŭ RTQEGUU KPENWFKPI FKHHGTGPV CRRNKECVKQPU
OCIPGVKE UJGGV Ŗ 2GT RTQEGUU
Heavy plate steel =*?ŭ =0?ŭ Ò & ENWUVGT ŭ
†O T 8CEWWO FGICUUKPI PKVTQIGP J[FTQIGP CPF
& UKPING KPENWUKQP ŭ †O 5WNRJWT TGOQXCN
6 1 ŭ T 8CEWWO QZ[IGP DNQYKPI FGICUUKPI ECTDQP
Wire =0?ŭ & ŭ †O 6 1 ŭ PKVTQIGP J[FTQIGP CPF 5WNRJWT TGOQXCN

STEEL TECH