Steelmaking Technologies Contributing to Steel Industries

Transcription

1 Steelmaking Technologies Contributing to Steel Industries Haruyoshi Tanabe Masayuki Nakada 21 JFE NKK developed steelmaking technology in the 20 th century while considering its social responsibilities. NKK developed and applied highly efficient production technology and produced high quality steel products while reducing the generation of wastes. The 21 st century will face a worldwide borderless society. Hence, the newly formed JFE Steel Corporation will develop new steelmaking processes and contribute to meeting diverse demands from around the world. 1. Zero Slag Process ZSP 5 1) Fig.1 KR New Refining Process NRP LDNRP JFE 21 ZSP % 0.10% CaO SiO2 3CaOP2O5 NKK No.179 ( ) 14

2 BF de[p] de[si] de[s] de[c] Fig.1ZSP process flow at NKK Fukuyama Works 150 Other de[si] NRP de[p] NRP 3 NRP LDNRP BOF 0 Before ZSP ZSP (Present) (Without desistation) % ZSP Fig.2The effect of ZSP on slag generation 0.012% Fig NK-CB 2) 100kg/t ZSP Mn 10kg/t Slag generation, kg/t Mn Mn 3) Mn % NKK No.179 ( )

3 (1) Stainless Steel Refining FurnaceSRF 6) 1 Ni Cr Fig.5 Ni Ni 4) 3 Fig.3 Cr CrNi RH NiCr Primary dust catcher Secondary dust catcher Hot metal Dephosphorization BOF Online dustmeter (colorimeter) <SRF> Ladle refining CC Fig.3Schematic view of online-dustmeter I C Ni ore reduction Cr ore reduction Decarburization (2) Fig.5Process flow of new stainless steel refining process 2.3 5) Fig RH 100 7) RH RH Dust generation index 0 Before ZSP Conventional lance ZSP Improved lance Fig.4Amount of dust generation Ar 30ppm 20ppm 8) RH 20ppm NKK No.179 ( ) 16

4 Ar 3. 20ppm ) Fig ppm m 6 49m m 3.0m Conventional 20 Improved ) [C] (ppm) 2m/min Fig.6Effect of improved RH FeO ZSP 10) HIC 14) Li2O 0.3kg/m 2 NKK Arc ProcessNK-AP 11) Fig m/min 2.4m/min Fig ) Li2O contained powder High crystallization temp. powder [N] (ppm) Fig.7Final ladle analysis of [S] Casting speed, m/min Non-sin oscillation Molten steel flow control system Low carbon Ultra low carbon Start-up of Fukuyama No.5 CCM Middle carbon (for plate) Start-up of Fukuyama No.6 CCM year Fig.8Change of casting speed at Fukuyama Works 17 NKK No.179 ( )

5 Magnetic coil Fig.9Annual production by No.5 CC at Fukuyama Works 6 Fig.11 90% 15) 2m/min 16) 220mm250mm300mm % 3.2 Fig.11Slab non-conditioning ratio (Sheet products) 19) 17) 18) 5 6 mm Fig.10 EMLS 20) (Electromagnetic Level Stabilizer) EMLA (Electromagnetic Level Accelerator) IBSRIntentional Bulging Soft Reduction 21) mm 330mm Nozzle Spouting stream Molten steel Meniscus Mold Magnetic coil Mold Electromagnetic Level Stabilizer Electromagnetic Level Accelerator Fig.10Molten steel flow control using traveling magnetic field NKK No.179 ( ) 18

6 5 M-EMS 22) 4. Fig.12Trend of diversion index of cold rolled coils RH 6 20 ZSP 4.1 AP 12) ( ) HIC MnS AP Ca IF 26) mm 6 IBSR 21) ZSP RH 5 ZSP Fig.13 HIC 23) RH 1983 NACE API-X ) IF Fig.12 ZSP Fig.13Annual production of sour gas line pipes ICP 24) 4.3 Ni 25) IF 150 ZSP 4.2 HIC ZSP AP 19 NKK No.179 ( )

7 SiO2 ZSP Table 1 28) 5.1 ( ) CaO Table 1Chemical composition of NKK potassium silicate fertilizer (%) K2O SiO2 CaO MnO MgO FeO Al2O3 CO CaO ph 5 29) Fig.14 1m 50cm ) 1 200kg CO CO2 100% 7. JFE Fig.14A pile of carbonated steelmaking slag blocks 1). NKK. No.169, pp.6 10(2000). 2). NK-CB. No.95, pp.13 20(1982). 3).. No.118, pp.1 7(1987). NKK No.179 ( ) 20

8 4). NKK. 17). No.176, pp.55 58(2002). CAMP-ISIJ. Vol.9, pp (1996). 5). 18). CAMP-ISIJ. Vol.10, p.777(1997).. Vol.33, No.6, pp (1994). 6). 19).. NKK. No.153, pp.6 11(1996). Vol.64, S207(1978). 7). RH CAMP-ISIJ. 20). Vol.8, p.271(1995).. No.121, pp.1 8(1988). 8). 2 C.N 21). CAMP-ISIJ. Vol.8, p.270(1995). CAMP-ISIJ. Vol.2, No.4, p.1158(1989). 9). RH CAMP-ISIJ. Vol.7, p.243(1994). 10). 4RH CAMP-ISIJ. Vol.7, p.1118(1994). 11). NK-AP). No.99, pp.12 21(1983). 12). Vol.66, S-258(1980). 13). 5.. Vol.72, S2233(1986). 14).. Vol.78, No.1, pp (1992). 15). 6. NKK.. 25). CAMP-ISIJ. Vol.15, No.2, p.251(2002). 26).. 27). 28. No.149, pp.1 8(1995). CAMP-ISIJ. Vol.13, p.859(2000). 16). 29)... Vol.83, No.2, pp (1997). 22).. NKK. No.136, pp.9 15(1991). 23). CAMP-ISIJ. Vol.5, p.1288(1992). 24). ICP. Vol.36, No.5, pp (1997).. Vol.69, S214(1983). NKK. No.167, p.67 68(1999).. 72(1) p.25 32(2001). 21 NKK No.179 ( )