LIU Yan
,
JIANG Mao-fa
,
XU Li-xian
,
WANG De-yong
钢铁研究学报(英文版)
For describing and resolving the process of chromium ore smelting reduction in a converter preferably, the coupling dynamic model was established based on the kinetic models of chromium ore dissolution and interfacial reducing reaction between the slag and metal. When 150 t stainless steel crude melts with chromium of 12% are produced in a smelting reduction converter with no initial chromium in metal at 1560 ℃, the results of the coupling dynamic model show that the mean reduction rate and injection rate of chromium ore are 0091 %·min-1 and 467 kg·min-1, respectively. The foundation of the coupling dynamic model provides a reference and basis on the constitution of rational processing route for a practical stainless steelmaking.
关键词:
coupling dynamic model
,
smelting reduction
,
stainless steel crude melt
,
converter
MIN Yi
,
JIANG Mao-fa
钢铁研究学报(英文版)
In this paper, exergy analysis was applied to the ladle furnace refining process of modern clean steelmaking. Results showed that, exergy loss induced by unavailable electric energy is the largest, and the electric energy efficiency is 46.20%. To cut down the unavailable electric energy, industrial experiments of submerged arc heating were carried out combined with slag composition modification. Results showed that, submerged arc heating can be achieved within most heating period, average heating rate increased by 0.5℃•min-1, unavailable electric energy decreased by 21.730 MJ per ton steel, and electric energy efficiency enhanced by 14.84%.
关键词:
LF (ladle furnace);exergy analysis;exergy loss;submerged arc heating
QU Tian-peng
,
LIU Cheng-jun
,
JIANG Mao-fa
钢铁研究学报(英文版)
The fluid flow in tundish is a non-isothermal process and the temperature variation of stream from teeming ladle dominates the fluid flow and thermal distribution in tundish. A numerical model was established to investigate the effect of inlet cooling rate on fluid flow and temperature distribution in tundish based on a FTSC (Flexible Thin Slab Casting) tundish. The inlet cooling rate varies from 0.5 to 0.25 ℃/min. Under the present calculation conditions, the following conclusions were made. When the stream temperature from teeming ladle drops seriously (for inlet cooling rate of 0.5 ℃/min), there is a “backward flow” at the coming end of casting. The horizontal flow along the free surface turns to flow along the bottom of tundish. The bottom flow shortens the fluid flow route in tundish and deteriorates the removal effect of nonmetallic inclusions from molten steel. Nevertheless, when the inlet cooling rate decreases to 0.25 ℃/min, the horizontal flow is sustained during the whole casting period. The present research provides theoretical directions for temperature control in teeming ladle and continuous casting tundish during production of advanced steels.
关键词:
tundish
,
thermal distribution
,
unsteady
,
numerical simulation
LIU Cheng-jun
,
HUANG Ya-he
,
JIANG Mao-fa
钢铁研究学报(英文版)
Clean high carbon heavy rail steel was prepared by the process of vacuum induction furnace smelting, forging and rolling. Mechanisms of RE on the impact toughness and fracture toughness for clean high carbon steel were investigated. In addition, the appropriate range of RE content for clean high carbon steel was determined. Both the austenite grain size and pearlite lamellar spacing decreased due to small amount of RE, consequently the impact toughness and fracture toughness were improved evidently. When the RE content exceeded a critical value, the pearlite lamellar spacing was increased, because RE was segregated on the austenite grain boundaries, damaged the orientation relationship of pearlite transformation, caused the disorder growth and morphology degenerating of pearlite. With the increasing of RE content, both the impact toughness and fracture toughness of clean high carbon steel were gradually increased at first and then decreased. It was found that when the RE content was between 00081% and 00088%, both the impact toughness and fracture toughness of clean high carbon heavy rail steel were the best. The maximum ballistic work was 212 J (20 ℃) and 122 J (-20 ℃), respectively. The maximum plane-strain fracture toughness was 4567 MPa·m1/2 (20 ℃) and 3704 MPa·m1/2 (-20 ℃), respectively.
关键词:
rare earth
,
high carbon steel
,
heavy rail steel
,
clean steel
,
impact toughness
,
fracture toughness
