The device can also be used for disassembling other similar parts, which has a very good promotion value. (: 2012-10 Preliminary Study on the Anti-sticking Sand Process of china Copper elbow Lost Foam Casting Wang Lingjun Liu Xiaojun Guo Qingjie 12 (1. Zhengzhou Golden Century Machinery Co., Ltd., Dengfeng 452473, Henan; 2. Daping Coal Mine of Zhengzhou Coal Group, Dengfeng 452473, Henan) Since the invention of the lost foam casting process, the coal mine electromechanical bookmark3 has been widely used because of its advantages of high production efficiency, low investment, low consumption, easy to master process technology, and low labor intensity. However, in use, the problem of sand sticky castings often affects The appearance quality of the product will cause the casting to be scrapped when serious, and cause a certain economic loss to the enterprise.

Therefore, it is of great significance to solve the problem of anti-sticking sand for castings. The vinyl plastic mold replaces the casting mold for modeling. The model is a solid mold. The vacuum negative pressure is used to solidify the dry sand and pour into the metal liquid to vaporize the model and replace the two to obtain an ideal casting. It is a molding method. The process is divided into the production of the model, the application of hanging paint, the drying of the model, the vibration modeling, the vacuum negative pressure pouring, the box cleaning, etc. Links. The sticky sand of castings is mainly mechanical sticky sand and chemical sticky sand. The reason for its formation mainly involves the following process links in the production of castings. The preparation of paint.

The mismatch between the water-resistant aggregate and the metal liquid causes chemical stickiness Sand; water-resistant aggregates are not water-resistant enough to resist the heat effect of the metal liquid. The water-resistant aggregates shrink greatly, and the paint has poor resistance to cold shock heat. Shedding or cracking when heated will cause the metal liquid to contact with the dry sand; The layer is too thin to effectively isolate the penetration of the metal liquid; the model is not dry when it is dried, or is placed improperly, so that the model regains moisture; the coating strength is not enough when spraying, or the coating peels off and not reapplied when packing. Cause mechanical sticky sand. Excessive vibration force or long vibration time will also cause the coating to peel off. High vacuum negative pressure will cause serious sand sticking. The degree of metal liquid penetration is proportional to the pouring temperature speed and pressure. The higher the temperature , The higher the speed, the higher the pressure, the easier it is to stick sand. The sand has a large particle size and poor thermal conductivity, and it is also prone to sticking sand. Improper setting of the riser will cause sticking when local overheating occurs Sand. 2 Anti-sticking sand process measures The formulation of anti-sticking sand measures involves all aspects of the production process and process performance. The selection of process parameters needs to take into account all process performances. The various processes on site production need to be closely coordinated before they can be done. The need for anti-sticking sand. This will not affect the other properties of the product, and can produce high-quality castings.

Based on the thermal field analysis of the specific internal energy distribution during casting and solidification, Determine benign heat field, bad heat field and homogenization degree of process heat element, bad heat element and heat field under various process conditions, analyze the main causes of casting defects, and adopt corresponding process measures to eliminate the influence on heat field distribution and obtain sound castings. Through machining bushing the analysis of three casting examples, the practical application of the thermal field analysis method is illustrated. However, the thermal field analysis method of casting process depends on fluid mechanics knowledge and rich casting experience.

At present, only qualitative analysis can be carried out, but quantitative analysis cannot be carried out or computer CAD can be realized. During the period from the time when all the molten metal is poured into the cavity to the time when the molten metal solidifies, the specific internal energy (energy J/kg per particle) distribution of the molten metal (including castings and gating systems) in the cavity with temperature as the surface symptom is the thermal field. In the traditional casting process theory, the material enrichment part in the casting geometric structure, that is, the part with large geometric section, is determined as the hot section, and the hot section is included in the process control focus.

These are all based on the fact that the temperature of the molten metal in the mold cavity is the same at the moment when the molten metal is poured. Then, according to the condition of uniform heat dissipation, the part with the smallest unit specific surface area, that is, the part with the slowest decrease in internal energy, is the final solidification part, that is, the part where the general hot spot is located. However, when the casting process is arranged by using the distribution of casting hot joints, process defects often occur in production practice, that is to say, defects caused by local overheating and overheating of castings do not necessarily appear at geometric hot joints. Therefore, the concept of thermal field is introduced. After pouring the mold,

Non-ferrous metal casting is a method of smelting metal, manufacturing a mold, pouring molten metal into the mold, and solidifying to obtain a metal part blank with a certain shape, size and performance. Non-ferrous metal casting blanks are almost formed, so that the purpose of avoiding machining or a small amount of machining reduces the cost and the production time to a certain extent. Non-ferrous metal casting is one of the basic processes of the modern device manufacturing industry. Compared with traditional processes, the non-ferrous metal casting process has a faster cooling rate of the metal mold, a denser structure of the casting, and can be strengthened by heat treatment.

The mechanical properties are higher than those of the sand casting. 15 %about. In addition, the quality of the non-ferrous metal casting is stable, the surface roughness is better than sand casting, and the reject rate is low. And the whole process has good labor conditions, high productivity, and easy for workers to master, which provides a good basis for casting high-quality castings. As for non-ferrous metal castings, like other castings, it must meet the requirements of some general technologies. The first is the material requirements, mainly hardness, tensile strength, elongation, and impact toughness.

There is also dimensional accuracy and shape and position accuracy. Different non-ferrous metal castings have different requirements. Different size and geometric tolerance standards and different tolerance levels gear shaft Manufacturers are used. According to the use requirements, acceptance requirements for other defects of non-ferrous metal castings, such as pores, trachoma, shrinkage, shrinkage, slag inclusion, sand inclusion, and cracks. Since there is a possibility of defects, of course, the requirements for defect repair of non-ferrous metal castings are also put forward.

This neutral system has machining bushing good adaptability to aluminum alloys, and can form a good film on a variety of aluminum alloys such as rust-proof aluminum and wrought aluminum.Electrochemical surface strengthening treatment of aluminum castings

It is determined to develop a new environmentally friendly chemical polishing technology using phosphoric acid monosulfuric acid as the base liquid, which will achieve zero emissions of NOx and overcome the quality defects of similar technologies in the past. The hub of the new technology is to add some special effects to the base liquid. Compounds are used to replace nitric acid. To this end, the tri-acid chemical polishing process of aluminum needs to be analyzed first, especially the role of nitric acid. The main role of nitric acid in aluminum chemical polishing is to attack by the point and improve the polishing brightness.

Combined with pure phosphoric acid The chemical polishing test in monosulfuric acid thinks that the special substance added in phosphoric acid monosulfuric acid should be able to erode according to the point and slow down the overall erosion, and at the same time it must have a good leveling and bright effectEnvironmentally friendly chemical polishing of aluminum castingsThe research of alkaline polishing solution system was carried out, and the effects of corrosion inhibitor and viscosity agent on the polishing effect were compared.

The alkaline solution system with good polishing effect of zinc-aluminum die casting was successfully obtained, and the operating temperature was reduced for the first time. Additives that extend the service life of the solution and improve the polishing effect at the same time. The experimental results show that adding appropriate additives to the NaOH solution can produce a good polishing effect. Exploratory experiments have also found that: NaOH solution with glucose is carried out under certain prerequisites After DC constant pressure electrolytic polishing, the surface reflectance of aluminum can reach 90%, but because of the undisturbed factors in the experiment, further research is needed. The feasibility of using DC pulse electrolytic polishing to polish aluminum under alkaline conditions was explored The results show that the leveling effect of DC constant pressure electrolytic polishing can be achieved by using the pulse electrolytic polishing method, but its leveling speed is slow.

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