Jingrui hardware, the most popular Shantou gravity

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When Jingrui hardware of Shantou Gravity Casting Co., Ltd. focused on Casting for 20 years, the injection speed not only affected the filling speed and injection inner gate speed, but also increased the impact peak value due to the high injection speed. Therefore, the high injection speed and the fast injection inner gate speed will intensify the scouring of the mold, increase the impact peak value, increase the impact force borne by the mold, and greatly reduce the service life of the mold. Therefore, when we adjust the die-casting process, it is very important for us to reduce the injection speed as much as possible while ensuring the product quality, so as to improve the service life of the die and the economic benefits of the die-casting enterprises. At present, advanced die casting machines are equipped with injection braking devices, which is very beneficial to reduce the impact peak value, reduce the impact force borne by the die and improve the life of the die

the injection specific pressure in the die casting process is also an important parameter. The injection specific pressure is generally in kg/cm2 according to the quality requirements and characteristics of the casting. If it exceeds 900kg/cm2, it generally has little effect on the internal quality of castings. However, if the injection specific pressure is too high, the die will not only bear more expanding force, but even exceed the clamping force of the machine tool, resulting in aluminum channeling. At the same time, if the die bears large expansion force, it will also damage the die or shorten the life of the die. Therefore, in die-casting production, we should not only pay attention to the injection speed, but also pay more attention to the injection specific pressure. Because the injection specific pressure is not high, we here adopt a tensile testing machine with high precision and small error to conduct tensile tests on it. It is easy to observe the injection speed, which is often ignored. In fact, the injection specific pressure is an important parameter in the die casting process, which not only affects the casting quality, but also has a great impact on the die life. This should arouse the attention of die-casting enterprises in particular

what are the advantages and benefits of aluminum alloy die casting we know

? Its advantages are mainly divided into five aspects:

1. Aluminum alloy has good thermal conductivity, conductivity and cutting performance

22. The linear shrinkage of sensor and aluminum alloy is small, so they have good filling performance, but the volume shrinkage is large, and it is easy to generate large shrinkage at the final solidification

3 aluminum alloy has low density and high strength. The ratio of tensile strength to density is 9 ~ 15. It also maintains good mechanical properties when working at high or low temperature

4. It is easy to stick the die during aluminum alloy die casting. Generally, the die sticking phenomenon can be reduced by controlling the mass fraction of aluminum alloy iron in the range of 0.8% ~ 0.9%

5. Aluminum alloys have good corrosion resistance and oxidation resistance. Most aluminum alloys have good corrosion resistance in fresh water, sea water, concentrated nitrate, acid, nitrate, acid, gasoline and various organic substances

, reasons for the shrinkage and porosity of die castings when aluminum alloy samples are supported on two blades: there is only one reason for the shrinkage and porosity of die castings, and the whole process resolution remains unchanged; That is due to the inevitable phase transition shrinkage when the molten metal changes from liquid phase to solid phase after filling As the solidification characteristic of die castings is cooling from the outside to the inside, when the wall thickness of castings is large,

the problem of shrinkage cavity and porosity will inevitably occur inside. Therefore, for die castings, especially for thick die castings, the problem of shrinkage cavity and porosity is inevitable and can not be solved

the only way to solve the shrinkage cavity and porosity defect of aluminum alloy die castings: the shrinkage cavity and porosity problem of die castings cannot be completely solved from the die casting process itself. To completely solve this problem, we can only go beyond the process, or seek solutions from outside the system. What is this method

in terms of process principle, the solution to the shrinkage cavity and porosity defects of castings can only be carried out according to the process idea of feeding. The phase transformation shrinkage of castings during solidification is a natural physical phenomenon. We can not go against the law of this natural phenomenon, but can only follow its law to solve this problem

in aluminum alloy die casting production, although the finish of the fixed mold cavity is very smooth, the phenomenon of sticking to the fixed mold still occurs due to the deep mold cavity. Dongguan aluminum alloy die-casting factory should analyze the structure of the casting, be familiar with the operation process of the aluminum alloy die-casting machine, understand the possibility of adjusting the aluminum alloy die-casting machine and process parameters, master the filling characteristics under different circumstances, and consider the processing method, drilling and fixing form of the aluminum alloy die-casting die before designing a practical and Specific production requirements of aluminum alloy die casting die

it has been said at the beginning of aluminum alloy die casting production that the filling time of liquid metal is short, and the specific pressure and flow rate of liquid metal are very high, which has a bad working condition for aluminum alloy die casting dies. In addition, the impact of alternating stress of cooling and heating has a great impact on the service life of aluminum alloy die casting dies. The service life of aluminum alloy die-casting die usually refers to the modulus of aluminum alloy die-casting die that can not be repaired under the conditions of normal use and good maintenance through careful design and manufacturing

porosity: it is mainly caused by pores and shrinkage mechanism. Pores tend to be round, while shrinkage is mostly irregular

(1) causes of air holes:

during mold filling and solidification of molten metal, air intrusion causes holes on the surface or inside of the casting

invasion of gas volatilized from coating

the air content of the alloy liquid is too high, and precipitates during solidification. Zhongshan zinc alloy die casting factory

when the gas in the mold cavity, the gas volatilized from the coating, and the gas precipitated from the alloy solidification are not well vented in the mold, they will eventually remain in the pores formed in the casting

II. Causes of shrinkage cavity:

during the solidification of molten metal, shrinkage cavity is generated due to the reduction of volume or the lack of feeding of molten metal at the last solidification position

uneven thickness of castings or local overheating of castings cause slow solidification at a certain part, and the surface will form a concave when the volume shrinks

due to the existence of air holes and shrinkage holes, water may enter into the holes during surface treatment of die castings. When baking after painting and electroplating, the gas in the holes will be heated and expanded; Or the water in the hole will become vapor and expand in volume, resulting in blistering on the surface of the casting

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