Shao J.-H.,University of Science and Technology Beijing |
Shao J.-H.,Tangshan Iron and Steel Co.
Gongcheng Kexue Xuebao/Chinese Journal of Engineering | Year: 2015
By using a thermal-state visualizable fluidized bed, the sticking of iron ore fines with different particle sizes was investigated under the condition of certain superficial gas velocity at 1073 K. It is found that according to different influences of particle size on the sticking, iron ore fines can be divided into three particle size ranges: small particle size at which sticking occurs in the neutral atmosphere under 1073 K, medium particle size at which defluidization happens when iron ore fines are reduced to low metallization ratio on the fluidized bed, and large particle size at which sticking does not appear on the fluidized bed, even to the end of reduction. The influence mechanism of particle size was analyzed in this paper. Moreover, under the normal fluidization condition, the swelling degree of the fixed bed after defluidization decreases with increasing particle size. © All right reserved.
Zhao D.,North China Electrical Power University |
Chen X.,Tangshan Iron and Steel Co. |
Zhang X.,North China Electrical Power University
Dianwang Jishu/Power System Technology | Year: 2011
The phasor measurement unit (PMU) based wide area measurement system (WAMS) provides a new thought and method for online voltage stability prediction. Adopting the π-type of branch model and by use of synchronous phasor measurement data, the voltage stability index based on branch power flow that can be used to HV power network is derived. In the viewpoint of physical meaning, the derived index can be explained as virtual active power margin index IVAM and an improved real-time voltage stability prediction index, which considers the IVAM variation of a certain tie line, is proposed. Calculation results of IEEE 14-bus system and that of a certain provincial power network show that the proposed index is accurate. The proposed improved voltage stability prediction algorithm is accurate and simple in structure, and it is easy to realize its online application.
Li J.-G.,Hebei Polytechnic University |
Zeng Y.-N.,Hebei Polytechnic University |
Wang J.-Q.,Hebei Polytechnic University |
Han Z.-J.,Tangshan Iron and Steel Co.
Journal of Iron and Steel Research International | Year: 2011
Based on the operating conditions of oxygen lance utilized for a 50 t converter in Tangsteel, gas jet flow fields of three types of oxygen lances were simulated by FLUENT software. The influence of lance configuration and lance level on penetrating area was studied through cold model experiment. The results showed that the gas flow velocities of four-hole, variable angle four-hole and five-hole oxygen lances declined rapidly with an increase in gas jet length within 1 m, 1 m and 0.8 m, respectively. Besides, the multi gas streams sprayed from these three lances should be syncretized at 1.6 m, 1.7 m and 1.4 m, respectively. At the highest lance level, the effective penetrating area of these three lances could be 0.255 m2, 0.385 m2 and 0.0907 m2, respectively. It was suggested that the effective penetrating area of variable angle four-hole oxygen lance was the biggest, while that of five-hole oxygen lance was the least. The validity of numerical simulation results was proved through cold model experiment. The lance level was suggested to be controlled in the range of 1 - 1.6 m, 1 - 1.7 m and 0.8 - 1.4 m for the four-hole, variable angle four-hole and five-hole oxygen lances, respectively. © 2011 Central Iron and Steel Research Institute.
Shao J.,University of Science and Technology Beijing |
Shao J.,Tangshan Iron and Steel Co. |
Guo Z.,University of Science and Technology Beijing |
Tang H.,University of Science and Technology Beijing
Steel Research International | Year: 2013
The effect of coating MgO with different methods on sticking behavior during the reduction of iron ore fines was investigated, at 1073 K with 70%CO-30%H2 gas mixture in a visualization fluidized bed. It was found that coating MgO on particle surface could extend fluidization time from 12 min to more than 80 min, and improve the degree of metallization from 22% to more than 80%. The expansion level of bed after defluidization could also be obviously decreased. To achieve a similar effect, the initial coating content with solution method was less than that with powder method. The reason was that coating MgO could effectively insulate the contact of metallic iron on particle, which provided the reaction time for carbon deposition and the production of Fe3C with low stickiness. Therefore, the decrease of metallic iron on particle surface led to the decrease of particle stickiness at high temperature. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Lin Z.,Control Iron and Steel Research Institute, China |
Xiong Z.,Control Iron and Steel Research Institute, China |
Liu H.,Control Iron and Steel Research Institute, China |
Zhang L.,Tangshan Iron and Steel Co.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2016
The critical transformation temperatures and CCT curves of DP600 dual-phase steel, Q&P steel and 22MnB5 steel were analyzed by thermal dilatometer, and the effect of alloying elements on the phase transformation behavior of high strength auto steel sheets was investigated. The results show that with the increase of heating rate, the critical point Ac1 and Ac3 of DP600 steel and 22MnB5 steel increase. Under the same heating rate, the variation of element content of these auto sheets have little effect on critical point Ac1. However, after adding Cr element, the Ac3 of DP600 steel decreases by 20 ℃, and with decreasing 1.0% Si and increasing 0.47% Al content of Q&P steel, the Ac3 point increases by 50 ℃, and after altering Si and Mn content of 22MnB5 steel, the Ac3 alters for 10 ℃. After adding Cr element, austenite-temperature curve of DP600 steel increases straightly, and the amount of austenite increases obviously at the same temperature. The austenite-temperature curve of 22MnB5 steel increases straightly, and its CCT curve moves to right after adding Cr, and the gradient of austenite transformation-temperature curve increases in amount of austenite transformation less than 40% after the decreasing of Si. The austenite-temperature curve of Q&P steel increases straightly and the austenite increasing rate slows down when the temperature is closed to the Ac3 temperature, and the austenitizing rate decreases when Al element is added. The carbon element delays the transformation of ferrite, pearlite, banite and martensite. The Cr element delays the transformation of pearlite and banite, reduces the critical cooling rate of martensite transformation, and improves hardenability of the high strength auto steel sheets. © 2016, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.