最新刊期
卷 30 ， 期 9 ， 2010
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- 摘要：Microstructure evolution of Al-Cu eutectic alloy in directional solidification was observed. The results reveal that at a given temperature gradient,with increasing in pulling velocity,eutectic lamellar spacing is decreased as a result of bifurcation of Al2Cu phase. During directional solidification process,adjustment of eutectic lamellar spacing is realized through bifurcation in longitudinal growth and mismatched boundary movement in the horizontal direction,and eutectic microstructure tends toward stable through continuous adjustment in longitudinal and horizontal directions.关键词：Al-Al2Cu Eutectic Alloy;Directional Solidification;Pulling Velocity;Lamellar Spacing
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发布时间：2023-12-18 - 摘要：Dynamic recrystallization behavior and microstructural evolution of Cu-2.0Ni-0.5Si-0.15Ag alloy during hot compressive deformation were investigated by isothermal compression testing at the Gleeble-1500D thermal-mechanical simulator at the temperature from 600℃ to 800℃ with strain rate from 0.01s-1 to 5s-1 under the condition of 60% strain. Recrystallized fraction at varied deformation conditions was determined based on σ-ε curves,which was employed to establish kinetic equation for dynamic recrystallization in the alloy. The dynamic recrystallized microstructure depend on the deformation strain rates. Relationship between the dynamic recrystallization grain and parameter Z is as follows: Ddyn=0.59×103Z-0.08.关键词：Cu-2.0Ni-0.5Si-0.15Ag Alloy;Dynamic Recrystallization Fraction;Kinetic Equation;Dynamic Recrystallization Grain Model
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发布时间：2023-12-18 -
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- 摘要：Effects of out-phase electromagnetic field on as-cast microstructure and mechanical properties of the 7075 aluminum alloy ingot were investigated by macro-microstructure observation and tensile testing. The results reveal that out-phase electromagnetic field can convert coarse heterogeneous feathery grain into fine equiaxed ones,greatly improving the microstructure in the 7075 alloy. Tensile strength of the 7075 alloy ingot is closely related to density of the microstructure and porosity（gas hole） . Tensile strength of the alloy ingot with compact and porosity-free feathery grain is remarkably superior to that of ones with low compact and high porosity equiaxed grain. Out-phase can effectively improve the microstructure and mechanical properties of the ingot.关键词：Out-phase Electromagnetic Field;Horizontal Continuous Casting;7075 Aluminum Alloy;Mechanical Properties;Macro-structure
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发布时间：2023-12-18 - 摘要：A cryogenic plasticity phenomenon appears in the extruded-T5 treated Mg-9Gd-0.6Zr alloy with tensioning at -196℃. Elongation of the alloy at -196℃ is one time higher than that at 25℃. The lattice constant （c/a values） of Mg-9Gd-4Y-0.6Zr alloy was measured by XRD （X-ray diffraction）. The results show that c/a values of extruded-T5 treated alloys are decreased to 1.6148 with adding Gd and Y elements,and it is further decreased to 1.6113 at -196℃,which results in the occurrence of multi-system slip by decreasing the critical shearing stress of prismatic slip systems at cryogenic tension. So the cryogenic plasticity of the alloy is superior to room plasticity.关键词：Mg-Gd-Y-Zr Alloy;Cryogenic Plasticity;Lattice Constant;Prism Slip
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发布时间：2023-12-18 - 摘要：Temperature change and metal flow behavior of indirect extruded 6005A aluminum alloy were analyzed by the FEM method and experimental verification. Based on the analyses,effects of practical extrusion parameters on properties of the alloy were analyzed. The results reveal that outlet temperature and extrusion loading peak value of the product are increased with increasing in ram velocity,while dead metal zone are shrank to the top of the die without shape change. Strain rate of the metal flow keeps constant with extrusion process tending toward steady stage. The microstructure and mechanical properties of the indirect extruded aluminum profiles are controlled by extruding temperature,ram velocity and extrusion ratio.关键词：Aluminum Alloy;Indirect Extrusion;FEM;Temperature Field;Metal Flow
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发布时间：2023-12-18 - 摘要：AM50 magnesium alloys were treated by micro-arc oxidation in a solution containing silicate,potassium fluoride,glycerol and potassium hydroxide at a constant applied anodic current density. Influences of different cathode current density on anodic voltage and micro-morphology,micro-hardness,thickness of coating were investigated at a constant anodic current density. The results indicate that anodic voltages corresponding to different cathode current densities exhibit firstly rapidly increase and then tend to be stable with increasing in time,while it shows firstly increase and then gradually decrease with increasing in cathode current density. In addition,with the increase of cathode current density,the number of micro-pores in the MAO coatings is firstly decreased and then increased,however micro-pore diameters are in range of 15 μm,exhibiting slightly change in size. It is beneficial for increasing micro-hardness and thickness of the MAO coating with increasing in cathode current density.关键词：Magnesium Alloy;MAO;Cathode Current Density;Anodic Voltage;Microstructure;Thickness
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发布时间：2023-12-18 - 摘要：The teeming and solidification process of ingot with 25 tons in weight was simulated by ProCAST software to understand effects of nozzle brick diameters on the flow filed of liquid steel. The results reveal that with increasing in nozzle brick diameters,outlet velocity of liquid steel is decreased,leading to the decrease of meniscus and the improvement of stability of liquid surface. With diameter of 0.12 m,liquid steel surface exhibits small horizontal flow velocity,which can more desirably prevent the slag entrapment compared with the initial sketch. In addition,adjustment of nozzle brick diameter only slightly changes temperature field.关键词：Steel Ingot;Nozzle Brick;Mold Flux;Inclusion;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Filling and solidification process of permanent mold casting Mg or Al alloy tensile testing bar were simulated by the ProCAST software to understand various physical field and to optimize gating system design. The simulated results are well in agreement with experimental ones. The results verify that the optimized gating system can effectively eliminate casting defects in the testing bar so that mechanical properties of the permanent mold casting bar are nearly the true value.关键词：ProCAST;Tensile Testing Bar;Permanent Mold Casting
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发布时间：2023-12-18 - 摘要：A mixture-based constitutive model was developed on the basis of the real mixture status of nanocrystalline materials to describe the mechanical properties of the materials. The nanocrystalline materials are composed of grain and grain boundary phases,and the grain boundary phases are assumed to have equivalent parts: part I and part Ⅱ. The strain of the part I is the same as that of the grain interior; meanwhile,the stress of the part Ⅱ is equals to the total stress of the grain and part I of the grain boundary,which is well in agreement with practical ones. Then the established model was applied to calculate the elastic modulus of porous nanocrystalline materials. Furthermore,the model is extended to describe the stress-strain relation with small plastic deformation. The model can predict the effects of grain size and porosity on the elastic modulus and yield strength of the nanocrystalline materials. The simulated results are well in agreement with experimental ones in small plastic strain range.关键词：Nanocrystalline Material;Elastic Modulus;Yield Stress
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发布时间：2023-12-18 -
- 摘要：As the important basic technical equipment in die casting production,die casting machine is also the technical support of the die-casting process updating and vital for process guarantee. Making a general survey of the development of China die casting machine manufacturing industry,it plays a great role in driving die casting industry improvement. Currently,there still exists a gap between China and world advanced die-casting industry,so die casting machine manufacturing industry should act in advance to strive continually for accelerating the development of the China die casting industry.关键词：Die Casting;Die Casting Machine;Die Casting Machine Manufacturing Industry
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发布时间：2023-12-18 - 摘要：A356.2 alloy semi-solid billets were prepared by near liquidus pouring combining with equal channel angular extrusion and semi-solid isothermal treatment. Equivalent spherical diameter and shape factor of the semi-solid billets were measured by metallographic microscope and metallographic analysis system. The results reveal that A356.2 alloy semi-solid billets with desirable properties in which average grain size is in range of 6090 μm and shape factor is in range of 0.70.9 can be successfully prepared by the composite technology. Semi-solid billets with fine rosette and lumpy grain can be obtained by near liquidus pouring,and grain accumulate severe energy of deformation through severely distortion and breaking during ECAE process,which results in the gradual transformation of grain into near-spherical and spherical structure with the increase of grain size.关键词：Near-liquidus Pouring;ECAE;Semi-solid Isothermal Treatment;Semi-solid Billets
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发布时间：2023-12-18 - 摘要：Semi-solid 5083 aluminum alloy billets were prepared by SIMA with hot extrusion at high extrusion ratio for pre-deformation. Effects of some processing parameters,such as extrusion ratio,isothermal temperature and holding time,on microstructure evolution of the semi-solid alloy billets were investigated,and influences of isothermal temperature on the segregation of dominant elements in the alloy billets were observed by SEM （scanning electron microscope） and EDS. The results indicate that microstructure evolution of the semi-solid alloy billets prepared by SIMA is closely related to the processing parameters. Desirable semi-solid 5083 alloy billets can be obtained with the extrusion ratio of 17.3 at 605℃ for 1520 min. Distribution of the Mn element in the alloy is independent of the isothermal temperature ,however,distribution of Al,Mg element are dependent on the temperature,where segregation is more and more serious with increasing in isothermal temperature. Low point phase segregated from the grain boundary is mainly composed of Mg element.关键词：SIMA Method;5083 Aluminum Alloy;Semi-solid;Microstructure;Composition Segregation
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发布时间：2023-12-18 - 摘要：By observing the morphological changes of primary austenite grains in as-cast hypoeutectic high Cr cast iron during isothermal remelting process in liquid-solid phase region,mechanism of its evolution was described. The results reveal that during isothermal remelting process,primary austenite phase is evolved from coarseness of net dendrite to fusion to spheroidization of grain and then to consolidation. Dendrite coarsening and fusing are dominant in evolution process at a lower remelting temperature,resulting in the difficulty of net austenite dendrite to be completely eliminated,while grain spheroidization and consolidation are dominant in evolution process at a higher remelting temperature. The equiaxed and uniform pre-eutectic austenite phase can be obtained in the high Cr cast iron at 1330℃ for 35 min. However,with increasing in heating temperature and in holding time,austenite phase can be seriously coarsened.关键词：Hypoeutectic High Cr Cast Iron;Primary Austenite Phase;Remelting;Evolution
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发布时间：2023-12-18 - 摘要：The microstructure and mechanical properties of ADC12 aluminum alloy connecting rod cap produced by die casting and by squeezing casting was comparatively studied. The results reveal that mechanical properties of the squeezing casting connecting rod cap are obviously superior to those of die casting ones. There exists obvious segregation in the microstructure of die casting connecting rod cap,while it exhibits compact structure in squeezing casting ones,so tensile strength,elongation and hardness （HRB） reach up to 367MPa,6.4% and 6466,respectively.关键词：Squeezing Casting;Die Casting;Microstructure;Connecting Rod Cap;Mechanical Properties
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发布时间：2023-12-18 - 摘要：It is a problem in solidification control and gas control for low pressure casting metal mold super-large aluminum alloy conductor （air tightness part）,compared to sand casting. Through setting rational pressure-applied parameters,adding processing supplement and setting rational chill,the conductor with compact structure can be produced. Meanwhile,gas hole in the conductor can be effectively eliminated by selecting rational filling parameters and enhancing exhaustion of metal mold as well as treating chill. The conductor passes examination after assembling.关键词：Aluminum Alloy Conductor;Air Tightness Parts;Permanent Mold;Low Pressure Casting
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发布时间：2023-12-18 - 摘要：Die casting process before and after modification for magnesium alloy absorber bracket was simulated by a software. Based on established magnesium alloy multi-physical filed modeling in quasi-solid region （90%<fs<100%）,change of solidification field,temperature field and stress field in the quasi-solid region was predicted,focusing on the change principle of quasi-solid region temperature gradient,equivalent stress-yield strength and maximum main stress-tensile strength. Formation of hot tearing and change of multi-physical field in hot-tearing zone were analyzed. The simulated results are well in agreement with experimental ones.关键词：Quasi-solid Region;Magnesium Alloy;Hot Tearing Formation;Die Casting;Simulation
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发布时间：2023-12-18 - 摘要：With common commercial raw materials,through rational proportion of various emulsifier,high efficient compound emulsifier was prepared,which was used to emulsify simethicone and polyethylene to successfully produce water-based releasing agent for aluminum alloy with stabile properties and desirable releasing effects. The releasing agent exhibits ideal in property indexes.关键词：Releasing Agent;Aluminum Alloy;Die Casting
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发布时间：2023-12-18 - 摘要：Effects of wax pattern assembling process,position and number of runner and riser system on deformation of easily-deformed investment castings were described. Adhesion wax was used to assemble wax pattern instead of electric iron,and runner and riser system was adjusted,which can keep assembled wax pattern in a desirable condition,greatly decreasing the modification difficulty in subsequent procedure.关键词：Wax Pattern Assemble;Deformation;Gating System
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发布时间：2023-12-18 -
- 摘要：Effects of equal channel angular pressing （ECAP） on microstructure and mechanical properties of spraying-deposited SiCp/7009Al composites were investigated. The results show that temperature has an obvious effect on the plastic behavior of the spraying-deposited composites during ECAP. The hard SiC particles were broken by the shearing stress,and many cavities in the broken SiC fragments occur,which can not be filled with the matrix alloy at a lower pressing temperature. Increasing the pressing temperature to above 350℃,the cavities from the SiC breakup can be filled with the matrix and flew with the matrix in a certain range,obviously improving the distribution uniformity,and the optimized pressing temperature is 400℃. The SiCp/7090Al composites experienced by Bc exhibits desirable mechanical properties and equiaxed grains with the average grain size of 400 nm can be obtained after four passes.关键词：Spraying Deposition;Composites;ECAP;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：TiAl3 particle reinforced Al-Si gradient composites were successfully prepared by adjusting super-conductive high magnetic field based on difference of susceptibility between the matrix alloy and the reinforcement. Distribution of TiAl3 particles in the solidification structure was observed,and effects of high magnetic field on motion behavior of the reinforcement were approached. Meanwhile,micro-hardness of the gradient composites was measured along axial direction. The results show that the micro-hardness exhibits gradient distribution in axial direction,which verifies the gradient distribution of reinforcement in the solidification structure.关键词：Metal Matrix Composites;High Magnetic Field;Al-Si Alloy
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发布时间：2023-12-18 - 摘要：Pure titanium was treated by micro-arc oxidation in metavannadate and in phosphate electrolytes,respectively. The structure and photo-physical properties of the two films were characterized by XRD （X-ray diffraction）,SEM （scanning electron microscope） and UV-Vis spectroscopy to understand its photocatalytic behavior. The results show that film with smooth surface and homogeneously distributed pore which is prepared in phosphate electrolyte （P-TiO2） is composed of a mixture of anatase and rutile,while the film with rough and less pores prepared in metavanadate electrolyte （V-TiO2） is composed of a mixture of anatase,rutile and V2O5. The band widths of P-TiO2 and V-TiO2 are 3.14eV and 2.28eV,respectively. The degradative rate of rhodamine is raised from 30% （P-TiO2） to 61%（ V-TiO2）.关键词：Micro-arc Oxidation;Metavanadate;V2O5/TiO2 Composite Film;Photocatalytic Degradation
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发布时间：2023-12-18 - 摘要：WC particle reinforced steel composites were prepared by tungsten inert gas （TIG） welding. Microstructure and phase constituent of the composite coating were analyzed by OM （optical microscope）,SEM （scanning electron microscope）,XRD （X-ray diffraction） and EDS （energy dispersive spectrometer）,and micro-hardness and wear resistance of the composite coating were measured. The results reveal that WC and W2C particles are dispersedly distributed into the dendrite structure in the cladding layer,meanwhile,Fe（W） solid solution phase and M6C phase can be observed in the structure of the composite coatings. Micro-hardness of the coating can reach up to 970 （HV0.1）,greatly improving the wear resistance of the 45 steel matrix.关键词：TIG Welding;Microstructure;Hardness;Wear Resistance
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发布时间：2023-12-18 -
- 摘要：Microstructure and mechanical properties of the trace alloying Mg-Al-Ca alloy prepared by spraying-deposition method were investigated. The results show that the alloy with 1%Nd content exhibits desirable comprehensive mechanical properties,in which fine secondary phase with average size less than 1μm is homogeneously distributed,and tensile strength and elongation reach up to 480MPa and 8%,respectively. The SEM （scanning electron microscope） analysis shows that secondary phase is Al2Ca phase with HCP structure. With increasing in squeezing ratio when it is less than 20,mechanical properties of the alloy are greatly improved,while squeezing ratio is more than 20,with it increases,increase of tensile strength tends to slow.关键词：Spraying Deposition;Mechanical Properties;Squeezing Ratio
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发布时间：2023-12-18 - 摘要：Al-5Ti-0.25C-2RE grain refiner was prepared by different RE adding sequences. Microstructure and refining efficiency of the master alloy on pure aluminum were investigated by optical microscope,X-ray diffraction. The results show that Al-5Ti-0.25C-2RE master alloys prepared by two kinds of processing are composed of α-Al phase,TiAl3 phase,TiC particle and irregular blocky or wrapped Ti2Al20Ce phase. Due to the promotion in the formation of TiC particle and improvement of the size of TiAl3 phase,desirable refining efficiency on pure aluminum can be obtained by adding 0.5% Al-5Ti-0.25C-2RE master alloy which is prepared by adding RE in early stage,compared with that prepared by adding in later stage.关键词：Al-Ti-C-RE Alloy;Preparation;Microstructure;Refining Efficiency
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发布时间：2023-12-18 - 摘要：With the help of thermal analysis system,the modification effects of RE on eutectic Si in Al-20Si-1.5Cu-0.4Mg alloy were investigated. Thermal analysis curves and microstructure of the eutectic Si with various RE additions were observed at a given P content of 0.08%. The results reveal that when RE addition is lower than 0.6%,with its increase,eutectic Si phase in the alloy is gradually converted from acicular structure into dispersedly short rod with decreasing in grain size,where eutectic growth temperature is decreased and difference of eutectic growth temperature is increased,showing better and better modification effects. However,with RE addition more than 0.6%,modification effects become worse,and eutectic growth temperature is increased with decreasing in difference of eutectic growth temperature. Difference of eutectic growth temperature exhibits desirable corresponding relationship with the modification effect of RE on eutectic Si.关键词：Hypereutectic Al-Si Alloy;RE;Modification;Thermal Analysis
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发布时间：2023-12-18 - 摘要：The aluminum alloy quasicrystal phase was prepared in the high aluminum,low manganese and low Ti alloy by vacuum induction melting and water-cooled copper mold. Effects of alloy composition,especially Ti content,on the microstructure and phase composition in the alloy were investigated by optical microscope （OM）,X-ray diffraction,scanning electron microscope（SEM） and EDS （energy dispersive spectrometer）. The results show that the prepared Al-Mn alloy is composed of decagonal quasicrystal T phase and its similar crystal phase （Al4Mn）. Ti addition can refine quasicrystal T phase grains and inhibit the formation of similar crystal phase. With Ti element more than 3% in atom percentage,some petal-like microstructure is observed in the alloy,which is identified as Al67Mn13Ti20 quasicrystal phase by X-ray diffraction and EDS analysis.关键词：Al-Mn Alloy;Al-Mn-Ti Alloy;Quasi-Crystal;As-cast Microstructure
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发布时间：2023-12-18 - 摘要：Effects of Cu on microstructure and mechanical properties of sand casting Al-Si-Cu-Ni alloy were analyzed by tensile testing,hardness testing and OM （optical microscope） and energy spectrum analysis. It is found that with increasing in Cu content,Al-Ni-Cu phase and CuAl2 phase in the alloy are increased,which results in the improvement of tensile strength of the alloy at room temperature and at 250℃ and decrease of elongation of the alloy.关键词：Al-Si-Cu-Ni Alloy;Al-Ni-Cu Phase;Elevated Strength;Microstructure
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发布时间：2023-12-18 - 摘要：Based on practical production,effects of pre-treatment of wear resistant ring,quality of liquid Al alloy,operation programs of the worker on the bonding quality of wear resistant ring in the piston were analyzed. After pre-treatment for wear resistant ring,on the one hand,cleanness of the wear resistant ring should be ensured,on the other hand,storage time should be strictly controlled to prevent erosion from the wear resistant ring. During production process,time of infiltrated-liquid aluminum alloy should be rationally controlled to avoid high Fe content and gas content in the liquid alloy influencing bonding quality of wear resistant ring. Before putting in or taking out wear resistant ring from the liquid Al alloy,oxidized film on working region of wear resistant ring should be cut to avoid oxide film adhering surface to form black oxide film defects. In addition,skills of worker should be improved to shorten transferring time of wear resistant ring,which could decrease the bonding defects of alloy. Based on above methods,the programs were set standard and strictly implemented,effectively decreasing scrap rate of the castings.关键词：Piston;Wear Resistant Ring;Pre-treatment;Infiltrated-liquid Aluminum Alloy;Oxide Film
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发布时间：2023-12-18 -
- 摘要：Hard spots in high strength and wear resistant aluminum brass components were investigated systematically by optical microscope,scanning electron microscope and EDS,micro-hardness testing. Origination of the hard spots in the aluminum brass parts was described,and countermeasures were presented.关键词：Aluminum Brass;Hard Spot;High Strength and Wear Resistance
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发布时间：2023-12-18 - 摘要：Characteristics of high lead bronze frictional ring and improvement of casting processing were described,including alkaline phenolic resin sand,metal mold casting and application of anti-tangent gating system. The practical production verified that the improved processing exhibits the features of simple programs,high precision and low cost as well as high efficiency. In addition,defects easily occurred in product and countermeasures were pointed out,which provided a reference for production.关键词：Permanent Mold Casting;High Lead Bronze;Frictional Ring
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发布时间：2023-12-18 -
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