A Dual Closed-Loop Digital Twin Construction Method for Optimizing the Copper Disc Casting Process

The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient production.However,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC optimization.To this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting process.Furthermore,a CPMC optimization model is proposed for the first time.On top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting process.Finally,a case study is carried out based on the proposed methods in the industrial field.

Distribution and engulfment behavior of TiB_2 particles or clusters in wedge-shaped copper casting ingot

Wedge-shaped copper casting experiment was conducted to study the engulfment behavior of TiB2 particle and the interaction between particle or cluster and the solid/liquid front in commercial pure aluminum matrix. The experimental results show that the particle size distribution obeys two separate systems in the whole wedge-cast sample. Furthermore, it is found that the big clusters are pushed to the center of the wedge shaped sample and the single particle or small clusters consisting of few particles are engulfed into the α-Al in the area of the sample edge. The cluster degree of particles varies in different areas, and its value is 0.2 and 0.6 for the cluster fraction in the edge and in the center of the wedge sample, respectively. The cluster diameter does not obey the normal distribution but approximately obeys lognormal distribution in the present work. More importantly, in the whole sample, the particle size obeys two separate log-normal distributions.

A DEVELOPMENT STUDY OF CAST COPPER ALLOYWITH HIGH STRENGTH AND HEAT－RESISTANCE

By means of Precipitation hardening, a cast copper alloy with high strength and heatresistance named Cu-6Ti-Cr-Al has been developed. This alloy has good castability. After water quenching at 860℃ for 1 h and aging at 450℃ for 4 h, the tensile strength, σ_b, is greater than 890MPa and the compressive strength, σ_(bc), reaches 1300MPa, while the ratio of compression, ε_c, is maintained at 20%. When the environmental temperature is raised to 450℃, the mechanical properties do not show any appreciable loss. These copper alloy castings have been used on the roll sleeves of rubber formers and the journal bearings of sheet mills. The results have shown that the service life of these parts is much longer than that of aluminium bronze and 904alloy castings. In the present work, the microstructure, mechanical properties and strengthening mechanism were investigated.

A Cast Copper Rotor Induction Motor for Small Commercial EV Traction: Electromagnetic Design, Analysis, and Experimental Tests

According to the demands of the small commercial electric vehicle(EV)traction driving system,an 18kW inverter-driven induction motor(IM)with a die-casting copper squirrel cage rotor for traction drive was designed and evaluated.The 2D finite element model of the designed IM was built by considering the nonlinearity of core materials,and the geometric parameters of the motor were optimized.The operational performance of torque versus speed characteristics and the efficiency over the speed range under the rated(continuous)and overload condition were investigated.Finally,the designed inverter-driven IM was developed and the performance of the IM operating in three typical modes were tested respectively.The experimental results of the designed motor operating in various driven mode were compared with that of 2D FEM.All the results proved that the designed inverter-driven IM could meet the target specification of the small commercial EV.

Optimization of pressurization process in low-pressure casting of a 5.4-ton gigantic C95800 copper alloy casting

During the low-pressure casting of extra-large size C95800 copper alloy components,traditional linear pressurization technique leads to a rapid surge of liquid metal inlet velocity at the regions where the mold cavity cross-section enlarges.This rapid increasement of liquid metal inlet velocity causes serious entrapment of gas and oxide films,and results in various casting defects such as the bifilm defects.These defects detrimentally deteriorate mechanical properties of the castings.To address this issue,an innovative nonlinear pressurization strategy timely matching to the casting structure was proposed.The pressurization rate decreases at sections where the cross-section widens,but it gradually increases as the liquid metal level rises.By this way,the inlet velocity remains below a critical threshold to prevent the entrapment of gas and oxide films.Comparative analyses involving numerical simulations and casting verification illustrate that the nonlinear pressurization technique,compared to the linear pressurization,effectively diminishes both the size and number of bifilm defects.Furthermore,the nonlinear pressurization method enhances the casting yield strength by 10%,tensile strength by 14%,and elongation by 10%.Examination through scanning electron microscopy highlights that the bifilm defects arising from the linear pressurization process result in the reduction of the castings’mechanical properties.These observations underscore the efficacy of nonlinear pressurization in enhancing the quality and reliability of gigantic castings,as exemplified by a 5.4-ton extra-large sized C95800 copper alloy propeller hub with complex structures in the current study.

Microstructure and storage properties of low V-containing Ti–Cr–V hydrogen storage alloys prepared by arc melting and suction casting

The microstructure and hydrogen storage properties of low V content （Ti0.46Cr0.54）100-xVx （x = 2.5-7.1, at%） and （TiyCr1-y）95V5 （y= 0.38-0.54） alloys were investigated. These alloys were prepared by arc melting and copper mould suction casting. The structures of as-cast （Ti0.46Cr0.54）100-xVx （x = 2.5, 5.0, and 7.1） alloy ingots evolve with V contents from pure Laves-（x = 2.5） to dual-phase TiCr2-BCC structures （5.0 and 7.1）, whereas the suction-cast （Ti0.46Cr0.54）100-xVx （x =2.5, 5.0, and 7.1） alloys only contain single BCC phase. The suction-cast alloy rod （Ti0.46Cr0.54）95V5, containing only 5.0 at% V is shown to possess the optimum hydrogen absorption capacity, with the maximum hydrogen content of 3.14 wt%. Furthermore, the hydrogen storage properties of the suction-cast low V alloys （TiyCr1-y）95V5 （y = 0.38-0.54） are sensitive to Ti/Cr ratios and only those alloys with Ti/Cr ratios close to the CN14 cluster [TiTCrs] have good hydrogen storage properties.

Cast bulk glassy alloys:fabrication,alloy development and properties

Metallic glasses represent an interesting group of materials as they possess outstanding physical, chemical and mechanical properties compared to their crystalline counterparts.Currently, with well designed compositions it is possible to cast liquid alloys into the glassy state at low critical cooling rates from 100 K·s-1 to 1 K·s-1 and in large critical sample sizes up to several centimeters, which significantly enhances the promise for possible applications as advanced engineering materials.This paper reviews the development of (ZrCu)-based bulk metallic glasses with large sizes by copper mold casting and their unique properties.Additionally, the ex-situ and in-situ second phases reinforced BMG composites with large plasticity are also presented.

Influence of niobium and yttrium on plastic deformation energy and plasticity of Ti-based amorphous alloys

Many amorphous alloys have been developed to date,but the low plasticity has limited their application.To achieve an amorphous alloy with high plasticity,a series of(Ti_(40)Zr_(25)Cu_(9)Ni_(8) Be_(18))_(100-x)TM_(x)(x=0,1,2,3,4 at.%,TM=Nb,Y)alloys were designed to study the influence of Nb and Y addition on the plasticity.The amorphous samples were prepared using the vacuum melting and copper mold casting process.The microstructures,glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),depth-sensitive nanoindentation,and uniaxial compressive test.The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy(PDE)during loading.The relationship between the PDE value and plasticity in bulk amorphous alloys was explored.Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands,which significantly increases the fracture strength and plasticity,while the addition of Y element reduces the fracture strength and plastic strain of the alloy.

Manufacture of Bulk Amorphous Crystal and Micro-Crystal for Pr_(60)Cu_((20-x))Ni_(10)Al_(10)Fe_x and Characteristics of Its Magnetic Apparatus

Bulk amorphous crystal and microcrystal for Pr60Cu(20-x)Ni10Al10Fex (x = 0, 8, 15, 20) with the diameter ofΦ2 ~ 6 mm were manufactured by electric arc smelting, high frequency heating and copper mold upper suction casting, and its structure was analyzed by X-ray diffract meter. It showed soft magnetic characteristic gradually when Fe content in it was up to 8% . The material was applied to magnetic-electric sensor as key component, output signal of which was measured with the change of Fe content. It shows that the signal changes from weak to strong with the increase of Fe content and presents the largest peak value when Fe is replaced by Cu completely.

Preparation of submicrocrystal Al-Ti-B master alloy and its influence on microstructure and properties of AZ91D

To improve the mechanical properties of AZ91D magnesium alloy,the submicrocrystal Al-Ti-B master alloy was prepared with copper mold inject casting method,and the influence of submicrocrystal Al-Ti-B master alloy on the microstructure and mechanical properties of AZ91D was investigated.Results show that,the distribution of Ti B_2 phase in submicrocrystal Al-Ti-B alloy is even and disperse,and the average size of Ti Al_3 phase is reduced from 10-30μm to～1μm.The properties of AZ91D refined with submicrocrystal Al-Ti-B master alloy are better than that with coarse-grained Al-Ti-B master alloy without copper mold inject casting.The tensile strength,elongation and Brinell hardness of AZ91D are increased by 10.6%,25%and 18.1%,respectively.Therefore,refinement of AZ91D with submicrocrystal Al-Ti-B that is obtained by copper mold inject casting is an effective method to improve its mechanical properties.

Calculation of Solidification Process of Continuous Cast Bar

In this paper,it presents the results of calculation of solidification process of copper continuous cast bar by cross section size 120 mm × 70 mm with application of Pro Cast 2010 software. The estimation of mould design effect on solidification process of continuos copper cast bar is completed at various speeds of casting.Profiles of liquid metal cavities and temperature allocations in the cast bar at various casting speeds are defined.The analysis of received liquid metal cavity profiles shows that a new mold construction allows significantly decrease of the length of the liquid metal cavity during continuous copper casting at HAZELETTcasting machine and the increase of maximum casting speed from 10 to 11 m / min. Adequacy of the results of copper continuous cast bar solidification process calculation is confirmed by the experimental data.

Microstructure evolution and magnetic properties of the Nd_9Fe_(81–x)Ti_4C_2Nb_4B_x(x=11, 13, 15) bulk magnets prepared by copper mold suction casting

The bulk nanocomposite magnets of Nd9Fes1-xTi4C2Nb4Bx （x= 11, 13, 15） in sheet form with the thickness of 0.7 mm were prepared by copper mold suction casting and subsequently annealing. The microstructure evolution and magnetic properties of bulk magnets were studied. It was shown that the as-cast microstmcture ofbtflk alloys were composed ofNdEFe14B, a-Fe, FeaB crystalline phases and an amorphous matrix, and that the glass formability of alloy was improved with increasing the B content. The DSC analysis showed that the as-cast bulk alloys had the crystallization behavior of a two-step process. After annealing at the temperatures which was 40453 K higher than their onset temperatures of the second exothermic peak, Nd9Fe81 xTi4C2Nb4Bx （x=11, 13, 15） bulk alloys obtained a finely mixed structure which were composed of Nd2Fe14B, a-Fe, Fe3B, （Nb,Ti）C crystalline phases and a residual amorphous phase, whose magnetic properties were significantly enhanced. For the bulk magnets of Nd9Fes1-xTi4CENb4Bx （x=11, 13, 15）, the optimal magnetic properties of Br=0.63 T, iHc= 155.1 kA/m, （BH）max= 18.73 kJ/m3 could be achieved when x= 13 after annealing at 983 K for 10 min.