Search1994 Vol. 1, No. 1-2
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1994, vol. 1, no. 1-2, pp.
1-7.
Abstract:
The distribution, morphology, composition as well as the transition of metastable carbides MC' in the initial atomized powders and in the various subsequent treatments in Ni-base P/M superalloy FGH95 have been studied. MC' has many kinds of complex morphologies and contains a large number of non-carbide forming elements. Conversion of MC' to stable MC during HIP consolidation promotes the formation of PPB carbides.Stabilization treatment applied to loose powders can improve the stability of MC' and change its distribution. HIP consolidation and hot extrusion can effectively eliminate PPB carbides and be expected to improve the alloy property.
The distribution, morphology, composition as well as the transition of metastable carbides MC' in the initial atomized powders and in the various subsequent treatments in Ni-base P/M superalloy FGH95 have been studied. MC' has many kinds of complex morphologies and contains a large number of non-carbide forming elements. Conversion of MC' to stable MC during HIP consolidation promotes the formation of PPB carbides.Stabilization treatment applied to loose powders can improve the stability of MC' and change its distribution. HIP consolidation and hot extrusion can effectively eliminate PPB carbides and be expected to improve the alloy property.
1994, vol. 1, no. 1-2, pp.
8-14.
Abstract:
On the basis of analyzing the mechanism of sintering porcess, the primary features of the Sectional Image of Sinter Machine End (SISME) were presented. In order to describe the variation of sintering process completely and accurately by using SISME feature, the secondary features extracted by means of mathematical transformation.Testing the SISME secondary features on some SISME samples, it was proved that the features have a good classification effect on sinter quality.
On the basis of analyzing the mechanism of sintering porcess, the primary features of the Sectional Image of Sinter Machine End (SISME) were presented. In order to describe the variation of sintering process completely and accurately by using SISME feature, the secondary features extracted by means of mathematical transformation.Testing the SISME secondary features on some SISME samples, it was proved that the features have a good classification effect on sinter quality.
1994, vol. 1, no. 1-2, pp.
15-21.
Abstract:
Electro-thermal explosion-pressing (ETE-P) and hot pressing composite powders synthesized by self-propagating high-temperature synthesis (SHS+HP) were used to produce dense Al2O3-TiC ceramics. The mechanical properties and cutting performance of SHS Al2O3-TiC ceramics were better than those of conventional hot pressing Al2O3-TiC ceramics cutting tools. The microstructure and densification mechanism of SHS Al2O3-TiC ceramics were discussed.
Electro-thermal explosion-pressing (ETE-P) and hot pressing composite powders synthesized by self-propagating high-temperature synthesis (SHS+HP) were used to produce dense Al2O3-TiC ceramics. The mechanical properties and cutting performance of SHS Al2O3-TiC ceramics were better than those of conventional hot pressing Al2O3-TiC ceramics cutting tools. The microstructure and densification mechanism of SHS Al2O3-TiC ceramics were discussed.
1994, vol. 1, no. 1-2, pp.
22-30.
Abstract:
Based on the appearance of minima of the free energy of mixing and maxima (or minima) of excess free energy, the formation of metastable compounds and eutectics during rapid solidification of metallic melts as well as the presence of miscibility gaps in the phase diagrams of a lot of binary alloys, calculating models of mass action concentrations for Cd-Bi,Ge-Al; Bi-Sn, Cd-Sn, Ag-Cu, Al-Ga; Si-Ag, Pb-Sn and Al-Sn binary metallic melts have been deduced. Good agreement between- the calculated and measured values shows that the calculating models reflect the structural characteristics of given metallic melts.
Based on the appearance of minima of the free energy of mixing and maxima (or minima) of excess free energy, the formation of metastable compounds and eutectics during rapid solidification of metallic melts as well as the presence of miscibility gaps in the phase diagrams of a lot of binary alloys, calculating models of mass action concentrations for Cd-Bi,Ge-Al; Bi-Sn, Cd-Sn, Ag-Cu, Al-Ga; Si-Ag, Pb-Sn and Al-Sn binary metallic melts have been deduced. Good agreement between- the calculated and measured values shows that the calculating models reflect the structural characteristics of given metallic melts.
1994, vol. 1, no. 1-2, pp.
31-35.
Abstract:
The fluid flow phenomenon in the tundish influences strongly not only on homogenization of the composition and the temperature, but also on separation of the nonmetallic inclusions. Based on the dimensionless Froude and Reynold number similarity criteria, the effect of the gas blowing on the fluid flow in the tundish is studied in a water model. The velocity of liquid stream is recorded by a high speed camera. and the residence time distribution curves of the flow are measured.The experimental result shows that the gas blowing is beneficial to the separation of nonmetallic inclusions.
The fluid flow phenomenon in the tundish influences strongly not only on homogenization of the composition and the temperature, but also on separation of the nonmetallic inclusions. Based on the dimensionless Froude and Reynold number similarity criteria, the effect of the gas blowing on the fluid flow in the tundish is studied in a water model. The velocity of liquid stream is recorded by a high speed camera. and the residence time distribution curves of the flow are measured.The experimental result shows that the gas blowing is beneficial to the separation of nonmetallic inclusions.
1994, vol. 1, no. 1-2, pp.
36-44.
Abstract:
Simulation experiments were carried out to compare the main differences between bubbling and jetting regimes during submerged powder injection. An Aqueous Particle Sensor (APS) was first used for direct measurements to detect size of the injection plume, particle penetration and dispersion into liquid and gas entrainment in jet flow. The effect of gas and powder flow rates (powder/gas loading ratio) were the main parameters for determining the injection regimes and particle behavior.
Simulation experiments were carried out to compare the main differences between bubbling and jetting regimes during submerged powder injection. An Aqueous Particle Sensor (APS) was first used for direct measurements to detect size of the injection plume, particle penetration and dispersion into liquid and gas entrainment in jet flow. The effect of gas and powder flow rates (powder/gas loading ratio) were the main parameters for determining the injection regimes and particle behavior.
1994, vol. 1, no. 1-2, pp.
45-52.
Abstract:
An optimal design method of vibration isolation system suitable for complex structures under stationary random excitation is proposed. This new method determines the installation position of vibration isolators and optimum control force on the determined positions,and searches for the optimal parameters of the vibration isolators on the basis of optimized control forces. Therefore, the forces translated by the isolators to the main systems can be made very much closer to the optimized control force and vibration level is lower than the permitted level. The repeated analyses of the system dynamic characteristics can be omitted a lot and the calculation speed can be quicken very much, the optimal installation positions and parameters can be obtained simultaneously. Because the prerequisite that the modes do not affect each other is not used, it can certainly be applied to the complex structures conveniently.
An optimal design method of vibration isolation system suitable for complex structures under stationary random excitation is proposed. This new method determines the installation position of vibration isolators and optimum control force on the determined positions,and searches for the optimal parameters of the vibration isolators on the basis of optimized control forces. Therefore, the forces translated by the isolators to the main systems can be made very much closer to the optimized control force and vibration level is lower than the permitted level. The repeated analyses of the system dynamic characteristics can be omitted a lot and the calculation speed can be quicken very much, the optimal installation positions and parameters can be obtained simultaneously. Because the prerequisite that the modes do not affect each other is not used, it can certainly be applied to the complex structures conveniently.
1994, vol. 1, no. 1-2, pp.
53-58.
Abstract:
The computer program of the pass schedule setting up is worked out in the paper. The program simulates the whole process of rolling metals in cold rolling condition. It includes the mathematical models of specific deformation energy, tension, coefficients of roll flattening, and of speed effect, deformation efficiency, etc.. On the basis of the limited conditions, entry thickness, exit thickness, rolling speed, tension, rolling force and rolling torque,etc. are calculated.
The computer program of the pass schedule setting up is worked out in the paper. The program simulates the whole process of rolling metals in cold rolling condition. It includes the mathematical models of specific deformation energy, tension, coefficients of roll flattening, and of speed effect, deformation efficiency, etc.. On the basis of the limited conditions, entry thickness, exit thickness, rolling speed, tension, rolling force and rolling torque,etc. are calculated.
1994, vol. 1, no. 1-2, pp.
59-63.
Abstract:
In this paper, a Section Profile Disassembly Reasoning Strategy[SPDRS] in computer aided cold roll form designing is developed Considering the variability and complexity of cold roll formed sections, the SPDRS is created to solve the problem of the representation of graphics information and that of the establishment of reasoning engine, which is the foundation of universal designing of roll contours for various sections. and which enables the application of Expert System in CARD. Based upon the concept of "Shape Element", the SPDRS is the art in which the forming characteristics of all kinds of shape elements abstracted from various profiles is and through which the recognition of graphic information and the reasoning of forming strategy are realized.
In this paper, a Section Profile Disassembly Reasoning Strategy[SPDRS] in computer aided cold roll form designing is developed Considering the variability and complexity of cold roll formed sections, the SPDRS is created to solve the problem of the representation of graphics information and that of the establishment of reasoning engine, which is the foundation of universal designing of roll contours for various sections. and which enables the application of Expert System in CARD. Based upon the concept of "Shape Element", the SPDRS is the art in which the forming characteristics of all kinds of shape elements abstracted from various profiles is and through which the recognition of graphic information and the reasoning of forming strategy are realized.
1994, vol. 1, no. 1-2, pp.
64-69.
Abstract:
This paper investigates the axial dynamic characteristic, under crossing of roll axes of 4-h strip mills, and establishes a reasonable dynamic model of axial vibration of roll system. Based on the predisplacement theory of tribology, the definition of axial rigidity between work roll and backup roll, and between work roll and rolled piece, is given.Axial damping characteristic of roll system is analyzed, and the scale of axial damping factor is established. The analysis of dynamic load amplification factor provides a reasonable basis for discussing the effect of axial force on roll bearings.
This paper investigates the axial dynamic characteristic, under crossing of roll axes of 4-h strip mills, and establishes a reasonable dynamic model of axial vibration of roll system. Based on the predisplacement theory of tribology, the definition of axial rigidity between work roll and backup roll, and between work roll and rolled piece, is given.Axial damping characteristic of roll system is analyzed, and the scale of axial damping factor is established. The analysis of dynamic load amplification factor provides a reasonable basis for discussing the effect of axial force on roll bearings.
1994, vol. 1, no. 1-2, pp.
70-75,89.
Abstract:
In this paper, sheet metal stress-strain relations in uniaxial and biaxial tension were theoretially and experimentally investigated. The interrelation of two n values respectively derived from uniaxial and biaxial tension test and their suitness for predicting sheet metal forming limits were given. The stress-strain relations of studied materials in uniaxial and biaxial tension were also used to analyse and calculate sheet metal deep-drawing process and its forming parameters. The results showed that the stress-strain relation under uniaxial tension stress state is more suitable to analyse sheet metal deep-drawing process.
In this paper, sheet metal stress-strain relations in uniaxial and biaxial tension were theoretially and experimentally investigated. The interrelation of two n values respectively derived from uniaxial and biaxial tension test and their suitness for predicting sheet metal forming limits were given. The stress-strain relations of studied materials in uniaxial and biaxial tension were also used to analyse and calculate sheet metal deep-drawing process and its forming parameters. The results showed that the stress-strain relation under uniaxial tension stress state is more suitable to analyse sheet metal deep-drawing process.
1994, vol. 1, no. 1-2, pp.
76-82.
Abstract:
The brightener CT-2 was shown to be a strong inhibitor to the deposition of zinc, increasing cathodic polarization by about 100 mV, decreasing the cathodic peak current by about 20 times, and also to be a very strong promoter of nucleation, increasing the nucleus number density by 2 orders of magnitude, so that it would be reasonable to get quality electroplates with fine grains, bright and smooth surface and very few defects by using the brightener.
The brightener CT-2 was shown to be a strong inhibitor to the deposition of zinc, increasing cathodic polarization by about 100 mV, decreasing the cathodic peak current by about 20 times, and also to be a very strong promoter of nucleation, increasing the nucleus number density by 2 orders of magnitude, so that it would be reasonable to get quality electroplates with fine grains, bright and smooth surface and very few defects by using the brightener.
1994, vol. 1, no. 1-2, pp.
83-89.
Abstract:
The influences of electroplating bath composition and technological parameters on Ni content in deposit have been investigated. The mechanism of Zn-Ni alloy codeposition has been discussed. The plating bath composition and technological conditions for bright Zn-Ni alloy coating containing 13% Ni with 6 times corrosion resistance compared with that of Zn coating have been determined.
The influences of electroplating bath composition and technological parameters on Ni content in deposit have been investigated. The mechanism of Zn-Ni alloy codeposition has been discussed. The plating bath composition and technological conditions for bright Zn-Ni alloy coating containing 13% Ni with 6 times corrosion resistance compared with that of Zn coating have been determined.
Electroless Deposition of Nickel-phosphorus Alloy—on the Surface Submitted to Cathodic Pulse Current
1994, vol. 1, no. 1-2, pp.
90-96.
Abstract:
The pulsed electroless deposition of nickel-phosphorus has thoroughly been investigated to find out the relationship of phosphorus content in deposits and deposition rate with parameters of pulse current and temperature. The accumulation of phosphite in the electroless nickel plating solution can be improved due to using pulse current. Futhermore, it was discovered that the reaction of the pure electroless nickel deposition was accelerated by the pulse current.
The pulsed electroless deposition of nickel-phosphorus has thoroughly been investigated to find out the relationship of phosphorus content in deposits and deposition rate with parameters of pulse current and temperature. The accumulation of phosphite in the electroless nickel plating solution can be improved due to using pulse current. Futhermore, it was discovered that the reaction of the pure electroless nickel deposition was accelerated by the pulse current.
1994, vol. 1, no. 1-2, pp.
97-103.
Abstract:
In this work, characters of the two phase of plume in the ladle refine furnace are studied, and the mathematical representation is established to stand for the central line velocity, anypoint velosity in the two phases region of the plume, average velocity. circulative flowrate time needed by mixing ratio in the ladle refine furnace and its hydrodynamic model. The results calculated with a series of mathematical formulae deduced in this work correspond with the experimental results.
In this work, characters of the two phase of plume in the ladle refine furnace are studied, and the mathematical representation is established to stand for the central line velocity, anypoint velosity in the two phases region of the plume, average velocity. circulative flowrate time needed by mixing ratio in the ladle refine furnace and its hydrodynamic model. The results calculated with a series of mathematical formulae deduced in this work correspond with the experimental results.
1994, vol. 1, no. 1-2, pp.
104-112.
Abstract:
Three kinds of nonclassical periodic plane-lattices with locally 8-, 10-, and 12-fold symmetry are proposed. they can be interpreted as the projections on the plane of space models consisting of different polyhedra.The Fourier-transform patterns of the space models have approximate 8-, 10-, and 12-fold rotational symmetry which is hardly distinguishable from the corresponding symmetry in the strict mathematical sense and qualitatively similar to the electron-diffraction patterns with 8-,10-, and 12-fold symmetry of corresponding quasicrystals. These lattice can be described by a new "composites" of the traditional translation operations and rotation operations. Nonclassical crystallographic groups are set up.
Three kinds of nonclassical periodic plane-lattices with locally 8-, 10-, and 12-fold symmetry are proposed. they can be interpreted as the projections on the plane of space models consisting of different polyhedra.The Fourier-transform patterns of the space models have approximate 8-, 10-, and 12-fold rotational symmetry which is hardly distinguishable from the corresponding symmetry in the strict mathematical sense and qualitatively similar to the electron-diffraction patterns with 8-,10-, and 12-fold symmetry of corresponding quasicrystals. These lattice can be described by a new "composites" of the traditional translation operations and rotation operations. Nonclassical crystallographic groups are set up.
1994, vol. 1, no. 1-2, pp.
113-117.
Abstract:
Mossbauer spectroscopy and micrographs of Nd2Fe14B and Nd2(Fe,Co)14B have been studied. Micrographs of Nd2Fe14B at 500℃ and the dependence of area of Mossbauer of occupying probaility of Fe atom in Nd2(Fe,Co)14B on Co concentration have been chiefly studied.
Mossbauer spectroscopy and micrographs of Nd2Fe14B and Nd2(Fe,Co)14B have been studied. Micrographs of Nd2Fe14B at 500℃ and the dependence of area of Mossbauer of occupying probaility of Fe atom in Nd2(Fe,Co)14B on Co concentration have been chiefly studied.
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