Xiang Jie Wang

Experimental Study on Horizontal Continuous Casting of 6061 Aluminium Alloy Bar Process

The aluminium alloy bar is mainly obtained by hot extrusion in the past. In order to increase the production efficiency and reduce the cost, a new mold is designed, and horizontal continuous casting is used to produce the aluminium alloy bar in this work. The results show that aluminium alloy bar can be cast by horizontal continuous casting. The asymmetry of the sump is overcome by optimizing the design of the mold. When the temperature of the melt was 730°C, casting speed is 650 mm/min, cooling water is 15 L/min, the quality of lubricating oil is 0.5 ml/min, and the ingot with good surface quality can be cast.

The Effect of Al-5Ti-1B and Combination Electromagnetic Field on Grain Evolution of Die Casting Commercial Aluminum

The effect of increasing the amount of added grain refiner and combination electromagnetic filed on grain size and morphology has been investigated by die casting of commercial aluminum. The results show the grain size and the grain morphology both are transited with the increasing of the addition of Al-5Ti-B. The grain size continuously decreased with increasing the addition of grain refiner. Without grain refiner additions, an obvious transition in grain size and morphology is observed with the application of low frequency electromagnetic field (LFES). The efficiency in grain refinement of LFES decreases with increasing the amount of grain refiner. However, even when the addition of grain refiner is 2 wt. % Al-5Ti-B, 63 % grain size reduction still is observed by the affect of LFES. This result shows that the LFES can enhance the efficiency in grain refinement of grain refiner.

The Effect of Casting Speed on Sump Shape and Ingot Surface of HDC Casting 7075 Aluminum Alloy Ingot

7075 aluminum alloy ingot with the diameter of 100 mm has been produced by horizontal direct chill casting in different casting speed. The effect of casting speed on the sump profile and the ingot surface quality was studied by sump profile observation. It was found that increasing the casting speed results in the deepening of the liquid pool, the adding of segregation knots and the reducing of cold shouts in the ingot surface. It is also found that the depth of the liquid pool is directly proportional to the casting speed and the squared radius of the ingot.

Numerical Simulation and Experimental Research on MAG Surfacing Deposited with Electro-Magnetic Stirring Controlling

Numerical simulation and deposited experiment of MAG welding are carried out on the conditions of Electro-Magnetic Stirring (EMS) in this paper. Based on the research of EMS welding arc action, a simple EMS-MAG welding Gaussian distribution model using whole heat flux density is established, which MAG welding arc and droplet transfer are regarded as one integrated system. The important additional magnetic field parameter in EMS-MAG surfacing deposited welding is considered in this model. The computer-aided arc measurement system is used to analyze the effects of additional magnetic field in MAG welding. Effects of excitation current on welding penetration and width are analyzed by deposited experiments. Many deposited experiments are used to adjust model parameters and verify the simulation results. By defining key parameter and optimizing the model on the basis of experimental data, it can improve the simulation accuracy effectively. The results show that the established Gaussian distribution model can be used to simulate EMS-MAG welding process.

Influence of Wiper Height on 7A55 Slabs

In this paper, weak water cooling technology by wiper is introduced for the casting of 520×1650 mm 7A55 alloy slabs. By analyzing from experiment comprehensively, it indicates that the position of wiper will exert big influence on slab quality. Under the conditions of the experiment, if wiper height is below the bottom of sump, there will be more than 70% possibility for slab to have cracks. If it is excessively higher than 80 mm, the top of the sump, porosity will incur and macro-segregation will be enlarged. The experiment determines the correct height of wiper.

Characterization of Solution Treatment on AA7A55 Alloy

The thermal stability of constituent particles in both as-rolled and solution treated in AA7A55 has been investigated by means of scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Three types of solution treatments were used to dissolve particles constituents. Whereas the degree of recrystallization aggravates which deteriorates the properties with increasing the solution temperature, a significant amount of recrystallization exists after utilizing 480°C solution treatment whereas a much smaller extent from 480°C to 490°C. And electrochemical and exfoliation corrosion matched with the degree of recrystallization. With increasing the recrystallization the corrosion become worse.

Study on the Asymmetric Hot Rolling of Aluminium Alloy Thick Plate

The development of aviation industry demands hot rolled aluminium alloy extra thick plates. However, it is quite difficult to obtain sufficient and uniform deformation of extra thick plate by conventional hot rolling process. The asymmetric hot rolling can generate an additional shear deformation and significantly improve the equivalent strain at the centre of the plate and consequently the uniformity of the microstructure, and mechanical properties. In the present work, the asymmetric rolling (ASR) was achieved by adjusting the diameters of the upper roll and the lower roll and was used to prepare hot rolled thick plate of an aluminium alloy. The effect of the asymmetric hot rolling process on the deformation, shape control, microstructure and mechanical properties was experimentally studied. The results showed that the ASR has a significant effect on metal deformation and can somehow refine microstructure and improve the uniformity of microstructure and properties although plate bending often happens during rolling process. This paper presents these results and gives corresponding discussions.

A New Approach of Casting Aluminium Alloy Bar by Applying Low Frequency Electromagnetic Field

Aluminum is the richest metallic element in the earth, the ingots cast by DC casting process are usually extruded into aluminum bars. When the final products do not require high strength, this process appears to be low efficiency and high cost. We try to design a new technology to cast aluminum bar by horizontal direct chill (HDC) casting process directly. An electromagnetic field is applied during the horizontal continuous casting of 6061 aluminium bar with a diameter of 30mm. The experimental results show the asymmetry of the sump can be overcome by electromagnetic field. Ingot with good upper and lower surface quality is obtained. The structure of ingot is refined and the angle between growth direction and horizontal direction becomes small with increasing casting speed.

Effect of Out-Phase Electromagnetic Field on the HDC Casting Process of Commercial Aluminum

Commercial aluminum ingot with the diameters of 100 mm is produced by conventional out-phase electromagnetic field HDC casting process. The out-phase electromagnetic field is applied on the HDC casting process. The effect of out-phase electromagnetic filed on the ingot surface and structure is investigated. The result shows that the out-phase electromagnetic field is more effective in improving the upper surface, while, has little function on the bottom surface. The macro/microstructure of the ingot is changed by the out-phase electromagnetic field. Very long and coarse columnar grains evolve to short and thin columnar grains with the application of the out-phase electromagnetic field.

Preparing Large Sized Billet of High Strength Aluminum Alloy with the Application of Low Frequency Electromagnetic Field

Grain refinement is quite important for producing 7050 alloy billet especially in large scale. Low frequency electromagnetic casting (LFEC) process was used to make 7050 aluminum alloy Φ500 mm billets and study the effect of electromagnetic field on the microstructure. The sound Φ500 mm billets of 7050 alloys without any grain refiner can be successfully prepared by the LFEC process. The results show that low frequency electromagnetic field has a significant grain refining effect on 7050 alloy and can effectively eliminate feather grain structure. The microstructures of LFEC ingot from the border to the center of the cross section are all equiaxed grains and are finer and more uniform than that of conventional direct chill (DC) cast billets. The LFEC process also shows a strong power to eliminate hot tearing during casting large sized billet of high strength aluminium alloy.