NGHIEN COfU - TRAO D6I
NGHIEN CUtJ LUYEN THEP CACBON TU' SAT XOP MIREX
STUDY ON MELTING CARBON STEEL FROM MIREX SPONGE IRON
ThS. Tran Cong Thflc>, PGS, TS. Dinh Ba Tru^
'TrUdng Dai bpc Cdng nghiep TP. Hd Chi Minh
^Cdng ty Co phan Khodng sdn vd Luyen kim Viet Nam
T6M TAT
Bdi bdo trinh bdy kit qud nghien cdu luyen mgt sd mde thep cacbon thdp diing idm loi que hdn til nguyen lieu sdt xdp MIREX. Sat xo'p Id mdt nguyen lieu mdi dung de luyen thep, dUdc sdn xudt hang cong nghe hodn nguyen triic tie'p qudng sdt d trang thdi rdn. Bdi bdo ciing trinh bdy ket qud nghien cdu thiet lap quy trinh cong nghe luyen thep td sdt xdp. Thdnh phdn vd tinh ndng 3 mac thep dUOc ndu luyen dat tieu chudn. Tii do, dd khdng dinh khd ndng sd dung sdt xdp MIREX de ldm nguyen lieu luyen thep chdt lUOng cao vdi thdnh phdn cacbon thdp, hdm liiOng P, S thdp, tinh chdt cO hoc vUOt troi so vdi thep cd thdnh phdn tUOngtii. Thep co the sd dung ldm ddy thep loi que hdn, thay the nhdp ngoai
Ttt khoa: SfltxOjp, MIREX, cong nghe hodn nguyen trUc tie'p quang sdt thep cacbon thdp, ddy thep loi que hdn.
ABSTRACT
This paper present a study on melting low carbon steel for core wire of welding electrode from MIREX sponge iron. Sponge iron, an advanced material of steelmaking, is produced by direct reduction iron process in solid state. The melting process of 3 grades steels are established. They chimicals components and mechanical properties accord to standard. This study prove, that MIREX sponge iron can be used for material to melting high grades steels with low carbon components and low P, S and they mechanical properties are higher compare with usual steel. The produced steels may be applied for core wire of welding electrode.
Keywords: Sponge iron, MIREX, direct reduction iron process, low carbon steels, core wire of welding electrode.
1. M u DAU cdc doanh nghiep sU dung gang va thep phe lam nguyen lieu sdn xuat thep, nen hdm lUpng cacbon Cho den nay, Viet Nam moi nam phdi vd tap chat thfldng cao vd khdng dn dinh, chi phu nh$P hdng chyc ngdn tan day ldi que ban, mdt hpp san xuat thep xdy dUng, Hien nay, MIREX da ioai day thep yeu cau chat lUpng cao vd dn dinh. sdn xuat dupe sat xdp, mdt nguyen lieu sach, ham Th^p Idm day Idi que ban cd dac diem Id thdnh lupng C% thap, hdm Iflpng tap chat, trong do P.
phan C%, thap, ham Iflpng t^p chat thap, nhat la S% thap, da md ra hudng tU sdn xual LLU ioi IJIK P. S%; cd th^ hpp kim hda bdng Mn hoac Si. Do hdn. Bdi bdo trinh bdy ket qud nghien cuu L i,, N " IM \
TAP CHi CC KHi VIET NAM *l* Sd 4 (Thdng 4 nfim 2013) I Q
NGHIEN C I J U - T R A 0 D 6 |
De luy^n thep tfl sat xdp sfl dung noi Id bazo, vdi thanh phan chu yeu la MgO = 80%; C r P 3 = I 8 % , cd hat < 0 , l m m chiem 98%, cdn lai hat nhd hon 1mm, dflpc sang Ipc, say khd, tdch cdc tap chat chfla sat. Trdn hon hpp vdi 1,5% bdt HjBGj vd 2% nUdc. Dam tflng ldp ddy sau dat ong Idt dam thanh ndi Id, cuoi cung hoan thien mieng Id. Thdo khudn dam thanh Id, trdt mpt ldp bdt Mg) cd dp hat min
<0,lmm.
dung sat xdp luyen thep cacbon thap. Ket qua nghien cflu da ehflng minh khd nang sfl dung sat xdp de luyen thep, trong dd cd the luyen dflpc mde thep cacbon thap va dUa ra quy trinh cdng nghe luyen thep lam ldi que hdn, cd the Ung dung rdng rai tai cdc doanh nghiep luyen kim, sdn xuat day ldi que ban thay the cho nhap ngoai.
2. NGHIEN CtJtJ THU'C NGHIEM
a.Thdnh phdn thep ldm loi que hdn (bang 1). Thep lam loi que ban dflpc luyen thfl nghiem theo 3 tieu ehuan:
- Thep SWRY, tieu chuan Nhat Bdn JIS G3503.
- Thep H08A, tieu chuan ky thuat Trung Quoc GB/
T3429-94.
- Thep ER70S, theo tieu chuan ASTM - My.
Bdng 1. Thdnh phdn thep ldm loi que hdn
That gian k Hinh 1. Quy trinh nhiet sdy noi Id.
Say khd vd thieu ket theo quy trinh hinh 1. Can say qua nhieu bfldc: de khd, say bdng bdng dien hodc say cui cudi cung nau me thep say ndi Id.
+ Trfldc khi luyen thep thfl nghiem, can kiem tra npi hinh Id, mat trong mdn deu, dp ddy tudng Id phdi dam bao tdi thieu > 100 mm. Id khdng bi an mdn cue bd. Kiem tra an b. Nguyen lieu luyen thep la sat xdp MIREX dang cue, todn vd boat dpng cdc thiet bi Id nhU he th6ng cd thdnh phan theo bang 2. Thep vun sach loai 1 cd thuy lUc, he thdng nfldc lam mdt, vdng cam thanh phan tflong dUOng CT3. Ngoai ra sfl dung mot flng, tu dien, tu dien ... Chuan hi lieu de nau sd chat trp dung va chat khfl khi. theo quy trinh cdng nghe.
TUu chuin
MQ3X3
GST M i l
U I » A W S A 9 . a H t c A t p
SWRTH
HHA
E R ; O S G
T h M i p M n M i h 9 c ( % )
C 0 ^
0,10™.
0 » 0 » Mn
"""
n:sM£i
, 4 0 , 8 0 SI
OEOmai
0,04 mm
0 M , . »
P T fi Cr Nl Cu
1 1 . 1 Kh6ngl6nhon o.iiio
ig»
tms am
tsaa
0023 IL2D 0,30
Q.20 D15 0 ^
OJO
™,
Bdng 2. Thdnh phdn hoa hgc cua sdt xdp MIREX Fe
90.87 C 1,05
Feo 8,50
Mp 0.33
Al 0.69
Si 0,95
Mn 0,80
P 0.07
S 0.06
Ld l u y e n : Ld t r u n g t a n 2 t a n / m e . P h d i lieu:
T o n g sat v u n k g 1,438 Sat x d p k g 8 0 0 F e M n k g 2 0 FeSi k g 5 D d v d i k g 5 0 c. Mgt so ddc diem cua quy trinh cong nghe + Chuan bi nau luyen:
-I- Nau luyen.
Ddng dien, khdi dpng Id vdi 40% cong suat, nau chay 1/3 Iflpng sat vun lam mdi. Sau dd, nap sat xop vdo 16 vdi toe dp 20kg/phiLt, vfla nap vUa nhan chim sat xdp bang thep phe cdn lai, khdng de sat xdp ndi tr^n mat, khdng dflpc de Id ddi lieu va treo lieu lam hif hdng tudng 16. Khi nUdc thep sdi, can giam cdng suat Id khdng de nudc thep trdo. Nap xong sat xdp nang cong suat Id va nap het so thep phe cdn lai.
Q TAP CHi CO KHi VIET NAM • Sd 4 (Thang 4 nam 2013)
NGHIEN CUTU - TRAO OOl
Trong qua trinh nau chay, can cfl vdo Iflpng xi trong 16, nghieng Id loai bdt xi. Khi lUpng thep long trong 16 dat Vt the tich 16, tien hanh lay mau de kiem tra so bd, nap het lieu kiem tra chinh thflc thanh phan hod hpe cdc nguyen td: %C, %S,
%P, %Mn, %Si. Can cfl vao thanh phan hda hpe de cho cdc nap lieu va chat khfl khi, khfl tap chat, cho den khi thep long dat yeu cau. Khi luyen thep cd hpp kim Mn, sau khi phdn tich ham Iflpng cac nguyen td S, P dat yeu cau, ndng nhiet dp thep ldng len ISSO^C, cho todn bd Iflpng SiMn vdo khuay ddo cho hod tan hodn toan lay mdu kiem tra thdnh phan %C, %Mn, %Si. Dieu chinh %Mn bdng FeMn, dieu chinh % C bang than antraxits, dieu chinh %Si bdng FeSi75...Kiem tra khd nang khfl Oxy trong thep Idng. Thep long trfldc khi chuyen sang cdng doan due lien tue phdi dUpc khfl bd Oxy triet de (%0^ - 20ppm).
+ Ra thep. Thdnh phan hod hoc cua tat ca cac nguyen td ca ban trong mde thep dinh nau theo ke hoach phdi hpp cdch theo tieu chuan.
Nhiet dp thep Idng trong Id phdi dat tfl I660°C - 1680"C. Nhiet dp quy dinh cho thep long trong thung rdt trfldc khi chuyen sang due lien tue la:
1620-Hl640''C (tlO^C). Ddi vdi thung thep rdt dau tien vao thung trung gian can dieu chinh nhiet dp cao ban thung rdt chdng ke tiep 10 - 20"C.
3. KET QUA VA P H A N T i C H
K^t qud phdn tich thdnh phan cac mde th^p thfl nghiem dflpc liet ke vdo cdc bdng.
a. Thdnh phdn hda hgc.
Bdng 3 liet ke thdnh phan hda bpc mdt sd mde thep cacbon thap luyen tfl sdt xop, theo tieu chuan SWRI vd H08A.
Bdng 4 liet ke thanh phan hda bpc cdc me th^p theo ER70S-6.
nhd de tang ham Iflpng C% tren 0,1%.
Bangs. Thdnh phdn cdc me thep ndu theo mac SWRI vd H08A. %
c
Si M n P S Cr Mo Ni Al Co Cu Ti Vw
0,0902 0,1161 0,1199 0,1238 0,1411 0,1390 0,1798 0,1537 0,1579 0,0311 0,0710 0,0722 0,0242 0,0281 0,0253 0,0406 0,0868 0,0918 0,0094 0,0109 0,0105 0,0733 0,0776 0,0765 0,0680 0,0551 0,0344 0,0078 0,0060 0,0083 0,1627 0,2039 0,2074 0,0009 0,0005 0,0005 0,0011 0,0006 0,0006 0,0047 0,0072 0,0058
Bang 4. Thdnh phdn thep luyen theo tieu chuan ER70S-6,%
c
Si S P Mn
Ni Cr Mo V Cu Ti Co AI
0,1229 0,5301 0,0227 0,0264 1,4525 0,0326 0,0210 0,0049 0,0022 0,0329 0,0024 0,0074 0,0839
0,1079 0,3429 0,0226 0,0277 1,7443 0,0315 0,0217 0,0053 0,0019 0,0323 0,0040 0,0074 0,1305
0,0931 0,7931 0,0200 0,0255 1.6007 0,0182 0,0209 0,0042 0,0041 0,0316 0,0012 0,0072 0,0396
- Ham Iflpng Mn: Ddi vdi mde thep H08A vd SWRI khdng can dieu chinh thdnh phan, ddi vdi mde thep ER70S can them MnSi;
Nhdn xet: - Thdnh phan cacbon thap, sau - Hdm IflOng P, S% chfla cd khfl tich . UL khi nau chay, chUa can dieu chinh thdnh phan
cacbon da dat yeu cau ddi vdi thep H08A vd - Hdm Iflpng cdc nguven tdkhni. do qu ir^, ER70S-6, chi cdn bd sung mpt Iflpng bpt graphit sat Iflu lai.
TAP CHi C O KHi VIET N.\M V Sd 4 (Thang 4 nam 2(H
m
NGHIEN C I J ( U - T R A 0 D 6 | Nhfl vay, sfl dung sat xdp dang cue cho ham Iflpng cacbon thap, do sdt xdp dang cue khi hodn nguyen hap thu rat it cacbon va sau hodn nguyen quang duac sdng sach, Iflpng cacbon dfl bdm ngoai It. Cung da cd thfl nghiem ve dieu chmh thdnh phan cacbon trong thep bang thay doi ty Ie sat xdp va thep phe. Thanh phan P. S%
thap hon nhieu so vdi hdm Iflpng P, S% trong gang, do khdng cd than cdc, nguon tap chat di vdo trong thep khdng cd. Sau khi nau chdy, thanh phan thep da dat thdnh phan thep tdt.
Hdm Iflpng Mn, Si khdng cao, phu thudc vdo Mn, Si% trong quang. De tang ham Iflpng Mn% theo yeu cau cua thep cd Mn%, can bd sung MnSi vdi sd Iflpng dflpc tinh todn trfldc.
N h u vdy, thep dflpc luyen tfl sat xop khdng nhflng eho dp sach cao, md cdn cho tinh nang cfl hoc tdt.
c. Ve cong nghe:
Sau nhieu lan thfl nghiem, mpt sd 16 bi hdng, tfl dd da riit ra dUpc mpt sd ddc diem khi luyen thep bang nguyen lieu sdt xop. De tranh mdn thanh Id can diing bdt MgO, dflpc chpn loc ky theo yeu cau ky thudt. Ky thudt dam ndi 16 va say Id can tuan thu nghiem theo quy trinh cong nghe. Khi nau luyen can khdng che tdt tdc dp nap lieu sat xop vd cdng suat 16. Khi cho sat xop, do chfla nhieu khdng khi, nen da dfla d xy bo sung vdo Id, can gia cdng suat de trdnh khuay ddo nfldc thep phd vd tudng 16.
Ham lupng cdc nguyen td hpp kim khae:
Nhan thay ham Iflpng mdt so nguyen to d gidi han 4. KET LUAN tren cua tap chat theo tieu chuan. Rieng quang
Cao Bang ed ham Iflpng Cu% d ngfldng tren theo tieu chuan.
b. Tinh chdt cd hoc
Cac me thep thi nghiem dflpc lay mau va gia cdng mau keo theo TCVN. Mau dflpc kiem tra tai Trung tdm do lUdng kiem chuan qude gia.
Bdng 5. Tinh ndng cd hgc mgt so mac thep luyen td sdt xop MIREX
1. Cd the sfl dung sat xop cua MIREX de luyen thep. Da luyen dflpc cdc mac thep dung che tao ldi que ban. Chat lUpng thep tdt, hdm lUpng C, P, S% thap. Cd the lam thep nen de luyen thep hpp kim dae biet.
STT 1
2
3
Tinh nang CO hoc Gicii han chay,
MPa Gidl han ben,
MPa Do dan dai,
Thep H08A 404 412 377 449 458 445 26 26 30
Thep ER70S-6t 400 408 444 503 487 498 28 30 28
2. Da sfl dung dUpc sat xdp luy$n thep trong 16 cam flng, vdi quy trinh cdng nghe chuyen biet va ky nang nau luyen, bao dam tudi thp cua ndi 16 vd tinh kinh te cua viee sU dung sat xdp.
3. Kien nghi nghien cflu on dinh chat lupng sat xdp va tiep tue sfl dung sat xdp luyen thep hpp kim vd cdc thep cd tinh ndng dac Met.'J*
Ngay nhdn bai: 12/3/2013 Ngdy phdn bien: 14/4/2013
Ngfltri phan Bien: PGS, TS. Dinh Van Chien, Trfldng Dai hpe Md - Dia chat Hd Npi.
Tal lieu tham khao:
(Sd dung 3 mdu thi nghiem, trgng thdi sau thUdng hoa).
Nhdn xet: Tinh ndng ep hpe cua cdc mde thep thUc nghiem hon ban tinh nang cua eac mde thep cd thdnh phan C, Mn, Si% tflpng dflOng ve gidi han chay, gidi han ben vd nhat la cho he sd dan ddi cao. Nguyen nhan do cd mpt so nguyen td vi Iflpng tan trong Fe trong qua trinh hodn nguyen.
[1]. Tieu chuan ca sd sat xdp MIREX, Cao Bdng 2012, 12]. Bao cdo ket qua nghien cflu san xudt sat xop vJ luyen thfl nghiem mot so mac thep, MIREX Cao Bdng, 2012.
13]. S.K. Dutta, (2004) Studies on DRI melting in induction furnace, Trans. Indian Inst. Met.Vol.57, No.
5,pp. 467-473.
TAP CHI CO KHi VIET NAM S6 4 (Thang 4 nam 2013)
