Search1997 Vol. 4, No. 1
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1997, vol. 4, no. 1, pp.
1-3.
Abstract:
According to the demand of modern surface mine production, production, a multi-objective optimum dispatching model is set up in this paper, it includes overall comprehensive optimal model, the goal programming model to optimize truck fleet in mine haulage system, and the selection of real time dispatching criteria. A surface coal mine is studied as a case in a built system simulation mantel, and the simulation result shows that the model is correct.
According to the demand of modern surface mine production, production, a multi-objective optimum dispatching model is set up in this paper, it includes overall comprehensive optimal model, the goal programming model to optimize truck fleet in mine haulage system, and the selection of real time dispatching criteria. A surface coal mine is studied as a case in a built system simulation mantel, and the simulation result shows that the model is correct.
1997, vol. 4, no. 1, pp.
4-7.
Abstract:
According to the coexistence theory of slag structures, the calculating model of the oxidizing capability for CaO-MgO-FeO-Al2O3-SiO2 refining slag system has been deduced. Based on this model, the concept and the calculating method of the optimum slag basicity are put forward. The results have proved that at this basicity,steel with lower oxygen content can be obtained and non-metallic indigenous globular inclusions can be avoided more effectively than at other basicity.
According to the coexistence theory of slag structures, the calculating model of the oxidizing capability for CaO-MgO-FeO-Al2O3-SiO2 refining slag system has been deduced. Based on this model, the concept and the calculating method of the optimum slag basicity are put forward. The results have proved that at this basicity,steel with lower oxygen content can be obtained and non-metallic indigenous globular inclusions can be avoided more effectively than at other basicity.
1997, vol. 4, no. 1, pp.
8-12.
Abstract:
Direct alloying of nickel oxide in a hot simulator of LD converter was investigated in laboratory. Reduction rate of nickel oxide in steelmaking process was analyzed with the test results. Under the condition of lower slag viscosity, the reduction rate of NiO increases and the [Ni] yield rises. When the slag viscosity is higher, a lot of metal particles with higher Ni content are contained in the slag so as to decrease the [Ni] yield.
Direct alloying of nickel oxide in a hot simulator of LD converter was investigated in laboratory. Reduction rate of nickel oxide in steelmaking process was analyzed with the test results. Under the condition of lower slag viscosity, the reduction rate of NiO increases and the [Ni] yield rises. When the slag viscosity is higher, a lot of metal particles with higher Ni content are contained in the slag so as to decrease the [Ni] yield.
1997, vol. 4, no. 1, pp.
13-15.
Abstract:
The technology of AODIF (Argon-Oxygen Decarburization Induction Furnace) for small scale smelting of special steels is introduced. The technology gives such refining capabilities as deep decarburization to common non-vacuum induction furnaces with effective control of temperature and chemical reactions respectively. After the disscussion of the phiscal chemistry basis involing decarburizaton,oxygen supply and heating features of AODIF,it has been found that altra-low carbon steels can be produced with precise control of smelting point by the reasonable and flexiable AODIF process, which permits both gas and solid oxygen supply.
The technology of AODIF (Argon-Oxygen Decarburization Induction Furnace) for small scale smelting of special steels is introduced. The technology gives such refining capabilities as deep decarburization to common non-vacuum induction furnaces with effective control of temperature and chemical reactions respectively. After the disscussion of the phiscal chemistry basis involing decarburizaton,oxygen supply and heating features of AODIF,it has been found that altra-low carbon steels can be produced with precise control of smelting point by the reasonable and flexiable AODIF process, which permits both gas and solid oxygen supply.
1997, vol. 4, no. 1, pp.
16-20.
Abstract:
The radiation induced segregation (RIS) was studied by electron/helium dual-beam irradiation. Within a grain, the content of Cr and Mn were higher in the center than at the margin of the irradiated areas. In the contrary, withim the irradiated areas included grain boundaries the contents of Cr and Mn decreased at the grain boundaries. RIS was weaker under dual-beam irradiation than that under electron single-beam irradiation, which was because of the increases of dislocation density and sink strength of voids when helium existed.
The radiation induced segregation (RIS) was studied by electron/helium dual-beam irradiation. Within a grain, the content of Cr and Mn were higher in the center than at the margin of the irradiated areas. In the contrary, withim the irradiated areas included grain boundaries the contents of Cr and Mn decreased at the grain boundaries. RIS was weaker under dual-beam irradiation than that under electron single-beam irradiation, which was because of the increases of dislocation density and sink strength of voids when helium existed.
1997, vol. 4, no. 1, pp.
21-23.
Abstract:
The texture of 80% cold rolling CuZn ordered alloy was investigated. The development of rolling texturein 50%Cu-50%Zn(at.) alloy has been characterized by a inhomogenous {111} fiber texture with strong {111} <112> component, which is significantly different from the conventional Cu-Zn alloys. The main characters of cold rolling textures in ordered CuZn alloy are obviously similar to that in IF steel with bcc structure or ordered Fe3Al-based alloys with imperfect B2 structure. From the rolling texture obtained by experiments and simulations,it can be estimated that main deformation mechanism are characterized by the activation of slip systems with <111> Burgers vector in CuZn ordered alloy.
The texture of 80% cold rolling CuZn ordered alloy was investigated. The development of rolling texturein 50%Cu-50%Zn(at.) alloy has been characterized by a inhomogenous {111} fiber texture with strong {111} <112> component, which is significantly different from the conventional Cu-Zn alloys. The main characters of cold rolling textures in ordered CuZn alloy are obviously similar to that in IF steel with bcc structure or ordered Fe3Al-based alloys with imperfect B2 structure. From the rolling texture obtained by experiments and simulations,it can be estimated that main deformation mechanism are characterized by the activation of slip systems with <111> Burgers vector in CuZn ordered alloy.
1997, vol. 4, no. 1, pp.
24-29.
Abstract:
On the basis of analyzing some limitations in the existing algorithm, a modified Monte Carlo method was proposed to simulate two-dimensional normal grain growth. With the modified method. the simulated time exponent of grain growth attained n=0.49±0.01, which is very close to the theoretical value of the steady grain growth n=0.5, indicating the possibility to investigate the total process of normal grain growth. The relation between the Hillert and the von Neumann equations were studied and identified, the Hillert's basic equation has been found to hold during the normal grain growth. The grain size distribution was found to van continuously and slowly with the simulated time in the total growth process, the lognormal and the Hillert functions may be two types of the expression forms during its transition, and the later seemingly corresponds at the distribution of the steady stage were n≈0.50.
On the basis of analyzing some limitations in the existing algorithm, a modified Monte Carlo method was proposed to simulate two-dimensional normal grain growth. With the modified method. the simulated time exponent of grain growth attained n=0.49±0.01, which is very close to the theoretical value of the steady grain growth n=0.5, indicating the possibility to investigate the total process of normal grain growth. The relation between the Hillert and the von Neumann equations were studied and identified, the Hillert's basic equation has been found to hold during the normal grain growth. The grain size distribution was found to van continuously and slowly with the simulated time in the total growth process, the lognormal and the Hillert functions may be two types of the expression forms during its transition, and the later seemingly corresponds at the distribution of the steady stage were n≈0.50.
1997, vol. 4, no. 1, pp.
30-35.
Abstract:
Hot ductility and strength of Continuous casting(CC) steels at elevated temperatures from CC processes were studied by physical simulation. The method is the hot ductility test. The design of test parameters and data interpretation are discussed. The results show that the bulging of CC steel slabs which is caused by the mechanism of creep has great influence on the formation of central segregation and internal cracks. Creep tests including static creep tests and dynamic creep ones were performed at 1200 and 1300℃. Effects of strain rate and temperature on hot ductility are also discussed and a simple model is presented to explain the interaction between hardening and softening.
Hot ductility and strength of Continuous casting(CC) steels at elevated temperatures from CC processes were studied by physical simulation. The method is the hot ductility test. The design of test parameters and data interpretation are discussed. The results show that the bulging of CC steel slabs which is caused by the mechanism of creep has great influence on the formation of central segregation and internal cracks. Creep tests including static creep tests and dynamic creep ones were performed at 1200 and 1300℃. Effects of strain rate and temperature on hot ductility are also discussed and a simple model is presented to explain the interaction between hardening and softening.
1997, vol. 4, no. 1, pp.
36-38.
Abstract:
Influence of the surface ultrasonic scratching pretreatment on diamond nucletion has been studied.Diamond films have been deposited on Si(100) by hot-filament chemical vapour deposition and characterized by scanning electron microscopy. 1.5~40μm diamond powders and mixtures of 1.5~5μm diamond as well as 5~20μm TaC powders were used in the ultrasonic scratching pretreatment. The experiment results show that the diamond nucleation density increases with increment of diamond powders size, and a mixture of diamond and TaC powders enhances diamond nucleation much more greatly than that of diamond powders alone, especially when the size of diamond powdets is not very large.
Influence of the surface ultrasonic scratching pretreatment on diamond nucletion has been studied.Diamond films have been deposited on Si(100) by hot-filament chemical vapour deposition and characterized by scanning electron microscopy. 1.5~40μm diamond powders and mixtures of 1.5~5μm diamond as well as 5~20μm TaC powders were used in the ultrasonic scratching pretreatment. The experiment results show that the diamond nucleation density increases with increment of diamond powders size, and a mixture of diamond and TaC powders enhances diamond nucleation much more greatly than that of diamond powders alone, especially when the size of diamond powdets is not very large.
1997, vol. 4, no. 1, pp.
39-42.
Abstract:
The microstructure of Ti-24Al-14NB-3V intermetallic alloy with solution treated was investigated by trans mission electron microscopy (TEM) and selected area electron diffraction (SAD) in conjunction with X-ray energy dispersive spectroscopy (EDS) techniques. It shown that φ=50% ductile β0-phase and small amount of O phase,and α2 with the number of dislocations having c-component resulted in increasing slip system of the material, have contributed to a good combination of strength and ductility at room temperature. Owing to some reciprocal planes of similarity between α2 and O Phases, to distinguish both of two phases, a series of diffraction patterns obtained by tilting around one reciprocal direction of the phase are needed based on the systematic extinction and reciprocal planes sequences occurred in the diffraction patterns, if those patterns are not containing one of three reciprocal unit vectors, a*, b*, c* in terms of the crystal unit cell, a, b, c.
The microstructure of Ti-24Al-14NB-3V intermetallic alloy with solution treated was investigated by trans mission electron microscopy (TEM) and selected area electron diffraction (SAD) in conjunction with X-ray energy dispersive spectroscopy (EDS) techniques. It shown that φ=50% ductile β0-phase and small amount of O phase,and α2 with the number of dislocations having c-component resulted in increasing slip system of the material, have contributed to a good combination of strength and ductility at room temperature. Owing to some reciprocal planes of similarity between α2 and O Phases, to distinguish both of two phases, a series of diffraction patterns obtained by tilting around one reciprocal direction of the phase are needed based on the systematic extinction and reciprocal planes sequences occurred in the diffraction patterns, if those patterns are not containing one of three reciprocal unit vectors, a*, b*, c* in terms of the crystal unit cell, a, b, c.
1997, vol. 4, no. 1, pp.
43-45.
Abstract:
The plastic zone at the tip of the flaw (including acute cark and common notch) was investigated. For the notch specimen, a formula of toughness KCR was proposed, and its physical meaning was emphasized.Two modes of brittle fracture was identified and the evaluating criterion was established.
The plastic zone at the tip of the flaw (including acute cark and common notch) was investigated. For the notch specimen, a formula of toughness KCR was proposed, and its physical meaning was emphasized.Two modes of brittle fracture was identified and the evaluating criterion was established.
1997, vol. 4, no. 1, pp.
46-53.
Abstract:
Superlattice phase transformation, occurred in the solute enriched region caused by diffusion induced grain boundary migration (DIGM), was found in two kinds of diffusion couples which consist of: (1) low carbon high strength steel with hot dipped zinc coating, and (2) commercial pure iron with galvanized zinc coating after isothermally diffusion annealed at different temperatures (500, 560 and 580℃) with various durations. The product of the transformation is an ordered phase with Li2 superlattice structure which was identified through the analysis by SEM,TEM and AEM. The ordered phase resulted from transformation occurred in the alloyed areas generated by DIGM and DIR The zinc content in this phase is variable, it approaches the stoichiometric composition Fe3Zn as the diffusion time is sufficiently prolonged. The mechanism of the transformation in connection with the process of DIGM and DIR was discussed. DIGM DIR and DIP (diffusion induced phase transformation) are three interrelated processed originated from grain boundary diffusion.
Superlattice phase transformation, occurred in the solute enriched region caused by diffusion induced grain boundary migration (DIGM), was found in two kinds of diffusion couples which consist of: (1) low carbon high strength steel with hot dipped zinc coating, and (2) commercial pure iron with galvanized zinc coating after isothermally diffusion annealed at different temperatures (500, 560 and 580℃) with various durations. The product of the transformation is an ordered phase with Li2 superlattice structure which was identified through the analysis by SEM,TEM and AEM. The ordered phase resulted from transformation occurred in the alloyed areas generated by DIGM and DIR The zinc content in this phase is variable, it approaches the stoichiometric composition Fe3Zn as the diffusion time is sufficiently prolonged. The mechanism of the transformation in connection with the process of DIGM and DIR was discussed. DIGM DIR and DIP (diffusion induced phase transformation) are three interrelated processed originated from grain boundary diffusion.
1997, vol. 4, no. 1, pp.
54-57.
Abstract:
Investigation on the effect of Fe-doped T1-1223 superconductors has been carried out by the simultaneous measurements of the spectra of positron annihilation lifetime and Doppler broadening of position annihilation,together with the measurement of Hall coefficient. The results of samples with different doping level show that the occupation of Fe atoms on Cu sites results in a linear decrement of superconducting transition temperature. The electron concentration in Cu-O layer has been enhanced by Fe doping. The difference in valence between Fe3+ and Cu2+ induces extra oxygen into the lattice and forms the extra oxygen defects. This Fe dopant leads to a strong localization of the electrons in the Cu-O layer. So the decrement of the concentration of the itinerant electrons results in a decline of the superconducting transition temperature.
Investigation on the effect of Fe-doped T1-1223 superconductors has been carried out by the simultaneous measurements of the spectra of positron annihilation lifetime and Doppler broadening of position annihilation,together with the measurement of Hall coefficient. The results of samples with different doping level show that the occupation of Fe atoms on Cu sites results in a linear decrement of superconducting transition temperature. The electron concentration in Cu-O layer has been enhanced by Fe doping. The difference in valence between Fe3+ and Cu2+ induces extra oxygen into the lattice and forms the extra oxygen defects. This Fe dopant leads to a strong localization of the electrons in the Cu-O layer. So the decrement of the concentration of the itinerant electrons results in a decline of the superconducting transition temperature.
1997, vol. 4, no. 1, pp.
58-62.
Abstract:
Nonclassical periodic lattices are classified and enumerated via the nonclassical crystallographic groups(NCGs). Some of the nonclassical periodic lattices might be used to construct larger unit cells to explain the structures of so-called quasicrystals or other nonclassical crystalline substances.
Nonclassical periodic lattices are classified and enumerated via the nonclassical crystallographic groups(NCGs). Some of the nonclassical periodic lattices might be used to construct larger unit cells to explain the structures of so-called quasicrystals or other nonclassical crystalline substances.
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