Improvement on Die Casting Process for Aluminum Alloy Cylinder Blocks of Automobile Engines (Part Two)
3. Improvement on die casting process of aluminum alloy cylinder blocks
3.1 Real-time parameter control
Improving the die casting process of aluminum alloy cylinder blocks for automobile engines, it is necessary to improve the real-time parameters of the aluminum alloy cylinder blocks and control the corresponding parameters to ensure that the product parameters can meet the specified standards. When the die casting process of aluminum alloy cylinder blocks is performed, it is necessary to strictly control the parameters of each link of die casting processing, and produce products with relatively good appearance and good quality within the specified parameter range. Once the product quality exceeds the specified range, the performance and quality of the product will be affected. When die casting process is performed, real-time control of the die casting processing technology needs to be carried out by the operator. Set the relevant parameters of the die casting process in advance, and when performing the die casting processing, the operator must also ensure that the entire processing process will not be affected by human factors, external factors and other factors to ensure the efficiency of product production.
In addition, when the die casting processing technology of aluminum alloy cylinder blocks for automobile engines is conducted, scientific adjustments should be carried out for the relevant parameters of the automobile engine to reduce the corresponding problems in the die casting and machining. When the corresponding parameters are monitored, if the parameters of the product exceed the range, the parameter should be adjusted scientifically.
4. Common defects and solutions of the aluminum alloy die casting process
4.1 Die casting gas holes
When automotive engine aluminum alloy die castings are processed, it is inevitable that the castings will have gas holes. The surfaces of these gas holes are very bright, and the shape of the gas holes is mostly circular. In order to avoid gas holes appearing on the castings, the pouring speed should be scientifically controlled during the die casting process, and the pouring system should be scientifically improved to avoid gas holes on the castings. In addition, when the die casting is processed, the processing personnel can also heat the die casting, which can also avoid gas holes on the die casting.
4.2 Slag holes
A slag hole is a defect that often occurs during the die casting process. The main cause is the oxidation reaction inside the casting. After the mold and coating of alloy liquids are oxidized, a certain residue will appear. When the alloy raw materials are poured to the inner cavity, many slag holes will be formed on the surface of the die casting. To avoid such defects, it is necessary to ensure that the quality of alloy materials can meet the specified requirements, and in this process, the materials must be refined to ensure that the purity of the alloy liquid can meet the specified requirements. In addition, when the pouring system is improved, it is necessary to ensure that all the oxidized residues can be discharged, and all these residues must be led to the slag bag.
4.3 Shrinkage porosity
The reason for the shrinkage porosity of automobile engines is mainly the pressure inside the cavity not being able to meet the specified cooling requirements after the alloy liquid enters the cavity. The solid metal shrinks greatly and the thick-walled liquid metal shrinks, mainly showing gas holes and looseness on the surface of the engine. The methods of eliminating shrinkage porosity are as the following: first, in the casting manufacturing process, the filling, pressure solidification and gradual principles must be strictly followed in the manufacturing process to ensure that the alloy liquid can be quickly, timely and effectively poured into the cavity under pressure. Second, lower the mold temperature before the liquid solidifies, and use the water-cooling low temperature method or partial pressurization method to process the liquid to reduce the occurrence of product defects and improve product quality.
5. Quality problem analysis and improvement
5.1 Reducing scrap rates
Generally, the scrap rate of products produced for the first time is relatively high, and it will decrease as the number of manufacturing times increases.
5.2 Reducing cracks
The occurrence of cracks will seriously affect the service life of the product. The main cracks are cracks on the outer wall of the cylinder water jacket and aluminum alloy cracks between the cylinder jackets. The former is mostly caused by excessive force during demolding, and this type of crack is a typical cold crack. The latter is mainly caused by a certain degree of shrinkage of the metal liquid after solidification, and the impact of the cylinder liner on the product tensile force causes cracks. The other is that the thickness of the casting cracks is thinner, and cracks are also easy to happen under the action of the thickness of two side walls. The cracks caused by these two reasons are typical hot cracks. Adjust the draft angle or change the right angle of the draft into a round corner to reduce the occurrence of cold cracks. For hot cracks, the preheating temperature of the cylinder liner can be adjusted to reduce the occurrence of hot cracks. Improving accuracy of the inside and outside of the cylinder liner is an effective way to reduce cold cracks and hot cracks.
6. Conclusion
The advantages of producing automobile engine aluminum alloy cylinder blocks through die casting process are very obvious, which can not only guarantee quality of automobile engine cylinder blocks, but also improve overall performance of automobile engines. In addition, the die casting process can also effectively control the quality of the aluminum alloy cylinder block of the automobile engine. The vacuum die casting technology is used to reduce the internal gas hole of the die casting, and the partial position of the runner gate is pressurized to avoid shrinkage porosity of the product.
3.1 Real-time parameter control
Improving the die casting process of aluminum alloy cylinder blocks for automobile engines, it is necessary to improve the real-time parameters of the aluminum alloy cylinder blocks and control the corresponding parameters to ensure that the product parameters can meet the specified standards. When the die casting process of aluminum alloy cylinder blocks is performed, it is necessary to strictly control the parameters of each link of die casting processing, and produce products with relatively good appearance and good quality within the specified parameter range. Once the product quality exceeds the specified range, the performance and quality of the product will be affected. When die casting process is performed, real-time control of the die casting processing technology needs to be carried out by the operator. Set the relevant parameters of the die casting process in advance, and when performing the die casting processing, the operator must also ensure that the entire processing process will not be affected by human factors, external factors and other factors to ensure the efficiency of product production.
In addition, when the die casting processing technology of aluminum alloy cylinder blocks for automobile engines is conducted, scientific adjustments should be carried out for the relevant parameters of the automobile engine to reduce the corresponding problems in the die casting and machining. When the corresponding parameters are monitored, if the parameters of the product exceed the range, the parameter should be adjusted scientifically.
4. Common defects and solutions of the aluminum alloy die casting process
4.1 Die casting gas holes
When automotive engine aluminum alloy die castings are processed, it is inevitable that the castings will have gas holes. The surfaces of these gas holes are very bright, and the shape of the gas holes is mostly circular. In order to avoid gas holes appearing on the castings, the pouring speed should be scientifically controlled during the die casting process, and the pouring system should be scientifically improved to avoid gas holes on the castings. In addition, when the die casting is processed, the processing personnel can also heat the die casting, which can also avoid gas holes on the die casting.
4.2 Slag holes
A slag hole is a defect that often occurs during the die casting process. The main cause is the oxidation reaction inside the casting. After the mold and coating of alloy liquids are oxidized, a certain residue will appear. When the alloy raw materials are poured to the inner cavity, many slag holes will be formed on the surface of the die casting. To avoid such defects, it is necessary to ensure that the quality of alloy materials can meet the specified requirements, and in this process, the materials must be refined to ensure that the purity of the alloy liquid can meet the specified requirements. In addition, when the pouring system is improved, it is necessary to ensure that all the oxidized residues can be discharged, and all these residues must be led to the slag bag.
4.3 Shrinkage porosity
The reason for the shrinkage porosity of automobile engines is mainly the pressure inside the cavity not being able to meet the specified cooling requirements after the alloy liquid enters the cavity. The solid metal shrinks greatly and the thick-walled liquid metal shrinks, mainly showing gas holes and looseness on the surface of the engine. The methods of eliminating shrinkage porosity are as the following: first, in the casting manufacturing process, the filling, pressure solidification and gradual principles must be strictly followed in the manufacturing process to ensure that the alloy liquid can be quickly, timely and effectively poured into the cavity under pressure. Second, lower the mold temperature before the liquid solidifies, and use the water-cooling low temperature method or partial pressurization method to process the liquid to reduce the occurrence of product defects and improve product quality.
5. Quality problem analysis and improvement
5.1 Reducing scrap rates
Generally, the scrap rate of products produced for the first time is relatively high, and it will decrease as the number of manufacturing times increases.
5.2 Reducing cracks
The occurrence of cracks will seriously affect the service life of the product. The main cracks are cracks on the outer wall of the cylinder water jacket and aluminum alloy cracks between the cylinder jackets. The former is mostly caused by excessive force during demolding, and this type of crack is a typical cold crack. The latter is mainly caused by a certain degree of shrinkage of the metal liquid after solidification, and the impact of the cylinder liner on the product tensile force causes cracks. The other is that the thickness of the casting cracks is thinner, and cracks are also easy to happen under the action of the thickness of two side walls. The cracks caused by these two reasons are typical hot cracks. Adjust the draft angle or change the right angle of the draft into a round corner to reduce the occurrence of cold cracks. For hot cracks, the preheating temperature of the cylinder liner can be adjusted to reduce the occurrence of hot cracks. Improving accuracy of the inside and outside of the cylinder liner is an effective way to reduce cold cracks and hot cracks.
6. Conclusion
The advantages of producing automobile engine aluminum alloy cylinder blocks through die casting process are very obvious, which can not only guarantee quality of automobile engine cylinder blocks, but also improve overall performance of automobile engines. In addition, the die casting process can also effectively control the quality of the aluminum alloy cylinder block of the automobile engine. The vacuum die casting technology is used to reduce the internal gas hole of the die casting, and the partial position of the runner gate is pressurized to avoid shrinkage porosity of the product.
