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Dai B.,Benxi Steel Plate Co. | Liu Y.-C.,Shougang Corporation
Journal of Iron and Steel Research | Year: 2015

By discussing the relationship between blast velocity and raceway length, the concept of reasonable blast velocity was put forward, further more, the theoretical foundation and influence factors of reasonable blast velocity were also analyzed in detail. What's more, the various phenomena of blast furnace with different blast velocities and the effective methods of adjusting the blast velocity were also clearly shown. Reasonable blast velocity that is not a definite number but a reasonable controlling range should be changed according to the change of blast furnace production conditions. So that looking for the reasonable blast velocity needs enough time to attempt and explore. Practice has proved that the active hearth and the long-term stable production of blast furnace could be realized only under the condition of reasonable blast velocity. Source

Li S.,University of Science and Technology Beijing | Kang Y.,University of Science and Technology Beijing | Zhu G.,University of Science and Technology Beijing | Kuang S.,Shougang Corporation
Materials and Design | Year: 2015

The purpose of this study was to evaluate microstructural and mechanical change of DP780 steel after tungsten inert gas (TIG) welding and the influence of notch locations on the fatigue crack growth (FCG) behavior. The tempering of martensite in the sub-critical heat affected zone (HAZ) resulted in a lower hardness (~. 220. HV) compared to the base material (~ 270. HV), failure was found to originate in the soft HAZ during tensile test. The fusion zone (FZ) consisted of martensite and some acicular ferrite. The joint showed a superior tensile strength with a joint efficiency of 94.6%. The crack growth path of HAZ gradually deviated towards BM due to the asymmetrical plastic zone at the crack tip. The FCG rate of the crack transverse to the weld was fluctuant. The Paris model can describe the FCG rate of homogeneous material rather well, but it cannot precisely represent the FCG rate of heterogeneous material. The fatigue fracture surface showed that the stable expanding region was mainly characterized by typical fatigue striations in conjunction with secondary cracks; the rapid expanding region contained quasi-cleavage morphology and dimples. However, ductile fracture mechanism predominated with an increasing stress intensity factor range (δ. K). The final unstable failure fractograph was subtotal dimples. © 2015 Elsevier B.V. Source

Li S.,University of Science and Technology Beijing | Kang Y.,University of Science and Technology Beijing | Zhu G.,University of Science and Technology Beijing | Kuang S.,Shougang Corporation
Journal of Materials Engineering and Performance | Year: 2015

The mechanical properties of DP780 dual phase steel were measured by quasi-static and high-speed tensile tests at strain rates between 0.001 and 1000 s−1 at room temperature. The deformation and fracture mechanisms were analyzed by observation of the tensile fracture and microstructure near the fracture. Dynamic factor and feret ratio quantitative methods were applied to study the effect of strain rate on the microstructure and properties of DP780 steel. The constitutive relation was described by a modified Johnson-Cook and Zerilli-Armstrong model. The results showed that the strain rate sensitivity of yield strength is bigger than that of ultimate tensile strength; as strain rate increased, the formation of microcracks and voids at the ferrite/martensite interface can be alleviated; the strain rate effect is unevenly distributed in the plastic deformation region. Moreover, both models can effectively describe the experimental results, while the modified Zerilli-Armstrong model is more accurate because the strain-hardening rate of this model is independent of strain rate. © 2015, ASM International. Source

He X.-F.,University of Science and Technology Beijing | Wang X.-H.,University of Science and Technology Beijing | Liang X.-L.,University of Science and Technology Beijing | Li H.-B.,Shougang Corporation
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2015

Based on SGRS technology, the effect of low basicity dephosphorization (De-P) slag in BOF slagless steelmaking was studied. According to the mass balance of slagless steelmaking, the lower the basicity of De-P slag is, the more CaO will be recycled and the more desilicication of liquid steel will be attained. At the same time, the experimental results show that, with the decrease of De-P slag basicity, the slag melting performance is gradually improved, leading to the beneficial outcomes of increasing the deslagging quantity and reducing the metallic iron content in De-P slag. When the basicity of De-P slag is 1.2-1.8, the hemisphere temperature of De-P slag could be controlled below 1 380℃, the free CaO content of De-P slag could be controlled at around 0.7%, and the amount of BOF deslagging in the end of De-P stage could be controlled more than 8 t (210 t BOF) or 5 t (100 t BOF). ©, 2015, Northeastern University. All right reserved. Source

Xue H.,Shougang Corporation | Jiang S.,Beijing Institute of Technology | Liang B.,China Automotive Technology and Research Center
Mathematical Problems in Engineering | Year: 2013

The increase of traffic flow in cities causes traffic congestion and accidents as well as air pollution. Traffic problems have attracted the interest of many researchers from the perspective of theory and engineering. In order to provide a simple and practical method for measuring the exhaust emission and assessing the effect of pollution control, a model is based on the relationship between traffic flow and vehicle exhaust emission under a certain level of road capacity constraints. In the proposed model, the hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (N O x) are considered as the indexes of total exhaust emission, and the speed is used as an intermediate variable. To verify the rationality and practicality of the model, a case study for Beijing, China, is provided in which the effects of taxi fare regulation and the specific vehicle emission reduction policy are analyzed. © 2013 Han Xue et al. Source

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