Advanced Materials Research Vols. 652-654

Abstract: The revamping & upgrading work has been done smoothly for the old soft-reduction system of the No.4 slab continuous caster in Bayi steel, as a result, all the segments (include both arc segments and level segments ) now have the dynamic soft-reduction function, which have been put into the industrial application successfully. Through the production practice, we can see that, after the revamping project, the dynamic soft-reduction function could be applied normally both in the arc segments and in the level segments for the No.4 slab caster, the whole soft-reduction process has been conducted steady and smoothly, the precision of roll gap control is good, the L2 model always makes an exact trace for the casting process and has the advanced algorithm, the L1 program has the reasonable control function and the reliable execution. When the soft-reduction action was executed in the unbending segment (Seg.7), there was no internal crack taking place for all the slabs, and the internal quality of slab such as center segregation was improved obviously, which had shown the metallurgical effect of the dynamic soft-reduction technology fully.

Abstract: Based on the general mathematical model given in Ref.[6] for porous copper fabrication under unidirectional solidification, interfacial shapes including both of solid-liquid and gas-liquid interfaces are given. Effects of argon partial pressure on interfacial shapes are considered. Results show that interfacial shape changes from convex to concave with argon partial pressure increasing for fixed hydrogen pressure. However, increase of argon pressure does not result in changes of interfacial shapes and location changes of interfacial tip are not obvious as argon pressure increasing for fixed total pressure.

Abstract: The paper describes multi-section round bloom casting using external MEMS, equipped with max section D600mm and min D280mm mold, the center line of D280mm mold not coincident with the axis of stirrer coils. it is exist eccentric electromagnetic stirring of mold which section less than max D600mm, a mathematical model of MEMS has been established, the index of central segregation of D280mm macrostructure had decreased less than 1.12 by optimized parameters of electromagnetic stirring and SEN immerse depth, in the end, the quality of round bloom had improved.

Abstract: Trace elements Sc was added to the Al-Zn-Mg-Cu-Zr alloys, the differences of the microstructure and properties using gravity casting and squeeze casting are compared. The result shows that through the addition of trace elements Sc, the Al-Zn-Mg-Cu-Zr alloys casting microstructure was refined effectively, dendrite segregation was alleviated and the mechanical property of alloy was enhanced. Using squeeze casting forming could improve the compactness of the alloys, decrease the probability of occurrence of shrinkage cavities, porosity and segregation, in addition, the grain could be refined by the pressure forced on the alloy melt. Combined the element Sc microalloying and squeeze casting used in Al-Zn-Mg-Cu-Zr alloy forming, we could get the casting with uniform, compact, little defect microstructures. This combination could provide a new way to the Al-Zn-Mg-Cu-Zr alloy forming.

Abstract: This paper introduces a die-casting mold design process. On the basis of the shape of Car oil pump support, central of castings’ side face was selected as the mold joint; due to the design requirements of pouring system, we chosen bias running system. Castings’ size was calculated by requirement of die casting machine, then accomplished designs of molding and structure’s components. Because through holes which on the side face of castings are not deep, angular pin core puller is competent, at last, the final assembly of the mold and the simulation is completed.

Abstract: Quantitative investigation is made on the elemental segregation in different zones of a heavy microalloyed cast steel by energy dispersive X-ray spectroscopy. It is demonstrated that C shows serious segregation tendency than that of Mn and Si, and the degree of C segregation in the surface zone is higher than that in the central zone. C enrichment is generally observed at both dendrite arm and grain boundaries, and more C segregation at dendrite arm boundary in contrast to that at grain boundary is found in this steel. The distribution of C concentration shows a decreased trend from root to tip along the dendrite arm boundary. The C concentration at trigeminal boundary intersection shows higher level than that at other position of the grain boundaries.

Abstract: Based on the chemical analysis and mineral composition research, a series condition tests were done with ore grade 1.45%.The optimum conditions were grinding fineness -0.074mm65%, collector as butyl xanthate- Ammonium aerofloat butyl(3:1) with 100g/t ,activator as sodium sulfide 200g/t,foaming agent as 2#oil of magnetite 30g/t. The result of tests showed that the grade of copper concentrate and the copper recovery are 8.98% and79.50% by adopting a circuit of one rough flotation, two scavenger.

Abstract: Based on the chemical analysis, preliminary classification of ore was done to reduce the content of iron mineral in quartz. The result of tests showed that the grade of quartz concentrate and the recovery are 97.05% and56.79% by adopting a circuit of magnetic- flotation processing.

Abstract: This paper makes systematic analysis of geological factors of natural gas accumulation in Denglouku formation of Gulong-Changjiaweizi region, including reservoir characteristics, gas source condition, source-reservoir relationship, structural condition, etc. It turned out that K1d2 in Gulong-Changjiaweizi region is generally typical tight sandstone reservoir with low porosity and permeability due to the poor physical properties. The gas source rock of K1d2 formation has larger gas producing capacity.The relationship between source rock and reservoir shows as interbed interfinger or directly contiguity contact, which is beneficial for large-area gas accumulation. The gas generation area of source rock in this region is always in the center and slow downdip direction of Gulong depression with a smaller dip angle on the adjacent tight sandstone reservoir, where faults are rare. The result of comprehensive analysis shows that K1d2 formation in Nothern Songliao Basin and its neighboring layers could be considered as a favorable target of the tight gas reservoir study in Northern Songliao Basin due to its favorable geological conditions of deep basin tight gas reservoir generation, such as tight reservoir, sufficient gas source, communicating source-reservoir relationship and constant flattened structure.

Abstract: The shale gas reserves could bring huge economic benefits. Therefore, many domestic and international scholars had researched it in all aspects. The research of seepage mechanism is mostly based on double seepage medium, they think gas spread directly into the fracture system when gas instantaneous desorbing from adsorption medium surface. However, the processing method is not very appropriate, because a certain amount of free gas present in rock matrixes pores. In order to describe the flow process accurately, this paper proposed a new concept of triple porous media, established a new model of shale gas seepage and solved the mathematical model by using Laplace transform and Stehfest numerical inversion. Finally figured out pressure dynamic response curves and analyzed the influence of all parameters on these curves.