最新刊期
卷 ， 期 5 ， 2002
- 摘要：Hydrogen content in molten aluminum at different temperatures and holding times was examined by means of Hyscan Ⅱ hydrogen analyser. The improved BP neural network modeling with 2 4 2 1 structure was adopted for training and testing by experimental data obtained. After learning for 3×10 5 times, max training error and RMS training error of BP neural network are 0.55%and 0.18%, corresponding to 0.72% max test error and 0.33% RMS test training respectively. The prediction precision is so high for the hydrogen content in molten aluminum that the response model between smelting condition （temperature, holding time） and hydrogen content may be established.关键词：Hydrogen Content;Neural Network;Molten Aluminum
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发布时间：2023-12-18 - 摘要：Al Ti C grain refiner was prepared by adding graphite powder in Al Ti alloy. The microstructure of Al Ti C alloy was observed by means of TEM,SEM and phase constituents of the refiner was detected by X ray. The results showed that TiC particle was firstly generated below 1 273 K and then transformed into Al 4C 3 with prolonging holding time while Al 4C 3 would be decomposed into TiC again over 1 573 K.关键词：Aluminum Alloy;Grain Refiner;TiC;Al 4C 3
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发布时间：2023-12-18 - 摘要：The effects of Zn on the solidification behavior, especially hot tear susceptility of Mg 9Al were examined. The solidification characteristics of the alloy were examined by thermal analysis. Crack rings sample was applied to estimate the hot tear susceptility of the alloy with introduction of the HSC（hot tear susceptility coefficient） concept. The solidification and hot tear behavior of the alloy were studied by optical microscopy, SEM and probe. The results showed that Zn and Al enriched in grain boundary due to the intercrystalline segregation during solidification process were increased with Zn addition to enhance the phase formation with low melting point and in turn to enhance the hot tear susceptility of the alloy. The hot tear originates at the later period solidification and propagates along grain boundary for Mg 9Al x Zn alloy. Zn addition can refine the grain of the Mg 9Al.关键词：Mg Al Alloy;Solidification;Zn;Hot tear
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发布时间：2023-12-18 - 摘要：Macro shrinkage and microstructure of TiAl alloy shaft casting were studied. The results showed that the solidification macro shrinkage rate varied as a function of with melt temperature s（%）=74.209 6-0.09 458 t +3.06 575×10 -5 t 2 and there are noticeable micro shrinkage in casting structure with pouring temperature ranging from 1 595 to 1 685 ℃ for TiAl alloy. Influence of three varities of casting processes on shrinkage distribution in TiAl alloy shaft castings was examined. The results showed that shrinkage porosity was distributed along axial line in gravity casting while volume shrinkage value decreased and porosity distribution deviated from the axial line in centrifugal casting, resulting in bending and rejecting the shaft casting during heat isotropic pressing（HIP）. The filling process of the shaft casting in centrifugal casting was simulated with wax. The results showed that at begining the front, and then the bact were filled through refluence in arbitrary cross section of the shaft casting during filling, resulting in axially asymmetrical distribution during solidification process in a cross section. The finally solidified part would be far from the axial line with deviation of the back. The serious deviation and the maximum deformation at intake place after HIP. It is proposed to alleviate asymmetrical distribution of the porosity for the shaft casting.关键词：TiAl Based Alloy;Shaft Casting;Centrifugal Casting;Porosity
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发布时间：2023-12-18 - 摘要：We have developed a equipment for directly rolling widely used spring steel（60Si2Mn） in semi solid sate in order to examine the rheological behavior and regulation and to grope directly rolling forming technology available for semi solid steel. The results showed that plastic deformation behavior of the solid phases differed from that of liquid phase during rolling, resulting in the difference of microstructure and properties between the center and the outer side of rolled product. Most of solid phase concentrates in the center while liquid phase flows toward the outer side. Plastic deformation rate of solid phase particulate increases with the increase of the solid fraction. Micro crack in surface of the rolled product attributes to either lower liquid phase fraction or higher deformation rate in the semi solid slurry or larger thermal differential between surface of the roller and the rolled product.关键词：Semi solid;Rolling;Solid Fraction
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发布时间：2023-12-18 - 摘要：Processing technology,microstructure and properties of as cast ferrite ductile iron auto hub in permanent mould were studied. Influence of Mn on microstructure was examined.关键词：Permanent Mould;As cast;Ferrite Matrix;Pre treatment
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发布时间：2023-12-18 - 摘要：A preformed Ti C Fe piece was immersed into liquid steel to in situ synthesize desirable TiC reinforced particulate. Afterwards, the melt containing TiC particulate was poured to prepare TiC particulate reinforced steel matrix composite. Influence of temperature and holding time of the steel melt and volume fraction of the synthesized particulate on the microstructure of the composites were examined emphatically. The composites with desirable microstructure were successfully prepared by optimizing above processing variables.关键词：Reactive Synthesis;TiC Particulate;Steel Matrix Composite
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- 305
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发布时间：2023-12-18 - 摘要：Model of 3 D flow field of crystallizer for beam blank was developed based on turbulent theory and characteristics of continuous casting. The model was applied to analyze flow field distributions with various nozzle and processing variables. It is found that the factors affecting the fluid flow of liquid steel in crystallizer are nozzle obliquity, immersing depth and drawing velocity. The results showed that it is beneficial to remove the inclusion at +15 ℃nozzle obliquity and to uniform flow field distribution at 0.9m/s drawing velocity. Proper nozzle depth is 200 mm. The model can be used to conduct off line analysis and to determine optimum variables as well as to lay the base of on line controlling model in continuous casting process.关键词：Crystallizer for Beam Blank;3 D Flow Field;Turbulent Theory
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发布时间：2023-12-18 - 摘要：Model that describes the flow and heat transfer in the crystallizer during inverse solidification was developed based on continuum equation. The variety of strip thickness in the crystallizer during inverse solidification was calculated by finite differential method. Strip thickness increases rapidly in initial stage, then keeps constant in middle stage, and finally rapid decreases due to remelting in last stage with the increase of holding time of the strip in liquid steel. Lower strip drawing velocity has slightly effect on the whole flow field due to the same flow of liquid steel tightly close to strip while local or the whole flow field changes with either higher or varying in drawing velocity. The calculated results illustrated that numerical simulation calculated data are well agreement with the experimental data.
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发布时间：2023-12-18 - 摘要：The principle and characteristics of continous casting with gas film forming for aluminum alloy rod as well as the developed status of gas film forming home and abroad were introduced. It is emphasized that attention should be paid to research and development of the technology at home.
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发布时间：2023-12-18 - 摘要：Molding shell should meet the higher requirements in the investment casting used for large and precision casting. The use of alcoholic ethyl silicate would be restricted and the silica sol would be more and more extensive because of the more strict environmental protection requirement. The proper selection of refractory materials and binders, the proper control of ratio of powder and liquid and viscosity of coating will raise the performance of molding shell greatly. The inspection ways for performance of molding shell were introduced.关键词：Investment Casting;Molding Shell;Binder.
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发布时间：2023-12-18 - 摘要：Die casting is a complicated process effected by numerous factors. A single method for quality control used not to achieve desired effect. The comprehensive diagnosis for diecasting defects,e.g. in aluminum time gear case and varying technological process are carried out with the combination of statistic, physico chemical analysis as well as technical simulation to determine character, regulation and reason for defect formation. On this basis, quality of the diecastings was improved remarkably through corresponding amelioration and optimization of casting process for the whole die casting. The results showed that the above mentioned comprehensive methods effectively provided the evidence for diecasting defect analysis and quality control.关键词：Aluminum Alloy;Diecasting;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Effects of extrusion pressure on the growth rate of macro\|crystal in extruded casting were investigated.The mathematical expression for the growth rate of crystal was developed.It is found that besides the alloy composition,under some particular extruded conditions,the extrusion pressure resulted in refining macro\|grain when increase in nucleation rate exceeds growth rate and vice versa.The refined dendrite is responsible for the decrease in distance between both of the first dendrite and secondary dendrite during quickening alloy solidified rate with the increase of the extrusion pressure.关键词：Extruded Casting;Crystal;Growth Rate;Arm Distance
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发布时间：2023-12-18 - 摘要：The thermal decomposition behaviors of aluminum titanate ceramic prepared with various stabilization additives at reducing atmosphere at 850 ℃（aluminum melt） were studied by means of XRD. The thermal decomposition rate of the aluminum titanate ceramic prepared with Y 2O 3+MgO as stabilization additive was only 4.3% in aluminum melt at 850 ℃ for 500 hours. The aluminum melt feeding pipe prepared with ceramic materials can be well operated at 700～900 ℃ for 60 days in low pressure die casting.关键词：Aluminum Titanate;Aluminum melt Pipe Feeding;Aluminum in Low Pressure Casting
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发布时间：2023-12-18 - 摘要：Interface reactions of TiAl alloy with three varieties of ceramic shell molds, including Al 2O 3, ZrO 2,ZrO 2 stabilized with CaO , were examined by EPMA, Vicker microhardness meter, optical microscope and SEM. The results showed that the chemical stability of these materials increased in the above sequence. The thickness of interface reactive layer between ZrO 2 stabilized with CaO and TiAl was merely 50 μm, so it can be applied to face coating materials in investment casting for TiAl alloy.关键词：TiAl Alloy;Investment Casting;Interface Reaction
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发布时间：2023-12-18 - 摘要：Gas hole and shrinkage porosity in the valves with massive flange were eliminated through altering design sketch of gating system. The valves were produced successfully by adopting bottom gating system, laying external chill and spreading chromite sand on hot spot position.关键词：Valves;Gating System;Hot Spot;Shrinkage Porosity
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发布时间：2023-12-18 -
- 摘要：A technique for making ceramic mold bound with phosphate was introduced. Both dimensional accuracy and surface roughness of the metal handicraft in ceramic mold meet technological requirement. Compared with ethyl silicate as bonding agent for traditional ceramic mold in investment casting, the phosphate binder has many advantages of simplified process, good adaptability and low cost. The ceramic mold can be used to some investment casting also.关键词：Phosphate Bonding Agent;Ceramic Mold;Art Casting
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发布时间：2023-12-18 - 摘要：Computer analysis software for microstructure of semi solid metal have been developed basedon OpenGL graphic environment. The software can be used for analyzing solid fraction and grain size in microstructure of semi solid metal. The software that has the advantages of good identifiable effect, powerful adaptability, fast running speed, simplified operation has been applied to analysis of microstructure of semi solid Mg alloy successfully.关键词：Semi solid;Analysis Software;Solid Fraction;Grain Size
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发布时间：2023-12-18 -
- 摘要：The market of cast Zn alloy ingot was analyzed and its quality was evaluated.The constructive suggestion to cast Zn alloy ingot enterprises in China was proposed.关键词：Zn Alloy;Alloy Ingot;Cast Alloy
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发布时间：2023-12-18
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