Luo Z.-A.,Northeastern University China |
Wang G.-L.,Northeastern University China |
Xie G.-M.,Northeastern University China |
Wang L.-P.,Shougang Jingtang Iron and Steel Co. |
Zhao K.,Northeastern University China
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals
The vacuum hot-roll bonding was carried out between TA2 titanium (Ti) and 304L stainless steel (SS) at 900°C. The vacuum hot-rolling bonding without interlayer and with niobium (Nb) interlayer was investigated, respectively. The microstructure and property of the interfaces were in-depth studied and the effect of the Nb interlayer was analyzed. The results show that many intermetallic compounds (IMC) are formed on the direct bonded Ti-SS interface, such as Fe2Ti, Cr2Ti and NiTi2. These IMC seriously weaken the shear strength, and lower shear strength of about 128 MPa is achieved. Inserting the Nb interlayer can effectively prevent the interdiffusion between Ti and SS. No IMC is found at Ti-Nb interface while IMC of FeNb is found at Nb-SS interface. The shear strength of about 338 MPa is achieved. The property of the clad plate is substantially enhanced by inserting Nb interlayer. Source
Xu J.-F.,University of Science and Technology Beijing |
Huang F.-X.,University of Science and Technology Beijing |
Wang X.-H.,University of Science and Technology Beijing |
Jing C.-L.,Shougang Jingtang Iron and Steel Co.
Metallurgical Research and Technology
The strategies for controlling resulfurization in a converter steelmaking process were clarified to produce pipeline steel with the KR-LD-RH-CC route, and the influence factors of resulfurization were investigated based on the industrial data and theoretical analysis. The results show that KR slag and lime account for the largest proportion of the sulfur-bearing materials of the sulfur in the converter. The influence of sulfur fluctuation in lime on the resulfurization was also significant. The removal ability of KR slag was greater by using a crawler loader than by using a slag-dredger. The steel resulfurization can be more effectively restrained by a conventional converter process than by a duplex converter process. Moreover, the rate-limiting step of the resulfurization in the converter is considered to be the mass transfer of sulfur from the interface toward the bulk of the slag phase, and slag with doubly saturated MgO and 2CaO•SiO2 was proposed to restrain the rate of resulfurization without changing the dephosphorization rate. The industrial experimental results show that the sulfur content of the steel before tapping into the ladle can be controlled at 0.002% to 0.003% when employing the above controlling strategies. © EDP Sciences 2015. Source
Wang C.,North China Electrical Power University |
Wei J.,North China Electrical Power University |
Sheng J.,North China Electrical Power University |
Li Y.,Shougang Jingtang Iron and Steel Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering
Blast furnace gas (BFG) produced from steel mill is a low heat value fuel, which combined with pulverized coal to combust in boiler is one of effective ways. However, the combustion characteristics would be changed greatly when compared with only pulverized coal combustion. For example, superheaters and reheaters are easy to excess rated temperatures and carbon content in fly ash will become higher, etc. All these problems lead to its limited application today. Take a 300 MW BFG/pulverized coal boiler for example, the combustion characteristics were simulated by means of two mixture fractions way. The pure coal condition and three BFG ratio: 10%, 20% and 30% conditions were investigated. It shows the temperature level in boiler is lowered obviously when BFG was mixed into boiler. For example, the maximal temperature is lowered about 81K when BFG ratio is 10% for a boiler section. Also, the temperature becomes lower with the BFG ratio. When BFG was mixed into boiler the flue gases volume would be increased. So, the actual stay time for pulverized coal in boiler will be shortened and it is more difficulty for coal to combust completely. Aslo, it is helpfully for control NO emission when BFG was mixed into boiler. © 2012 Chinese Society for Electrical Engineering. Source
Jing C.,Shougang Jingtang Iron and Steel Co.
Steel Research International
Industry trials of slag-washing desulfurization in LD tapping process are performed to study the influence of silicon on desulfurization of Al-killed steel using CaO-Al2O3 slag contained FeO and MnO. Influence of silicon on desulfurization is found to be great, while the influences of aluminum and manganese on desulfurization are negligible. Oxygen activity at slag-steel interface together with the (FeO+MnO) content in slag, decreased with the rise of silicon content, which is considered as the main reason of different desulfurization efficiencies between Si-free steel and Si-containing steel. Oxygen activity at slag-steel interface is reduced more sharply by increasing the silicon content than that by increasing the aluminum content. As a result, desulfurization efficiency can be enhanced significantly with the rise of silicon content, rather than the aluminum content. Furthermore, the influence of silicon on desulfurization can be magnified if the slag contained FeO and MnO, while negligible for the slag with few FeO and MnO. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Wang J.-J.,University of Science and Technology Beijing |
Hao J.-J.,University of Science and Technology Beijing |
Guo Z.-M.,University of Science and Technology Beijing |
Wang Y.-M.,Shougang Jingtang Iron and Steel Co.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy
Spherical niobium powders were prepared by radio frequency (RF) plasma from irregular niobium powders. The effect of feeding rate on the spheroidization efficiency was studied. The phase composition, morphology and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser micron sizer (LMS). The results show that niobium powders after plasma processing have good dispersity and smooth surfaces, and spheroidization ratio is almost 100%. The particle size distribution becomes narrow after spheroidizing. The loose density, tap density and powder flowability significantly increases after the treatment. The loose density increases from 1.33 g/cm3 to 4.35 g/cm3 and tap density increases from 1.95 g/cm3 to 5.61 g/cm3. The powder flowbility increases to 12.51 s/(50 g). With increasing the feeding rate, the spheroidization ratio of niobium powders drops gradually. Source