Precautions during the use of die-casting parts:
(1) Poor corrosion resistance. When the impurity elements lead, cadmium, and tin in the alloy composition exceed the standard, it leads to aging and deformation of the casting, manifested as volume expansion, significant decrease in mechanical properties, especially plasticity, and even rupture over time. Lead, tin, and cadmium have very low solubility in die castings, and therefore concentrate at grain boundaries to become negative. Aluminum rich solid solutions become positive, promoting intergranular electrochemical corrosion in the presence of water vapor (electrolyte). Die castings age due to intergranular corrosion.
(2) Due to insufficient locking force, poor clamping, insufficient mold strength, and high melting temperature, die-casting parts may have burrs on the surface. This phenomenon is called product flaking, and is often a post-processing process that enterprises need to face. At present, manual polishing, hydrogen oxygen explosion, and Zhaoling freezing shot blasting machines are mainly used to solve the problem based on the product properties.
(3) Die castings should not be used in high and low temperature (below 0 ℃) working environments. Die castings have good mechanical properties at room temperature. However, the tensile strength and impact performance significantly decrease at high temperatures and low temperatures.
(4) Time effect. The microstructure of die castings is mainly composed of zinc rich solid solutions containing Al and Cu and Al rich solid solutions containing Zn. Their solubility decreases with the decrease of temperature. However, due to the slow solidification rate of die castings, the solubility of the solid solution becomes saturated at room temperature. After time, this oversaturation phenomenon will gradually dissipate, causing slight changes in the shape and size of the casting.
The thickness of the wall of a die-casting component is called wall thickness and is a significant factor in the die-casting process. The correct wall thickness of die-casting parts depends on the specific structure of the casting, the performance of the alloy, and is closely related to the die-casting process parameters. In order to meet various requirements, thin walls and uniform wall thickness are preferred.
(1) It is not advisable to increase the thickness of the wall to enhance the load-bearing capacity of die-casting products. When the wall thickness of the casting exceeds the limit, its mechanical strength will decrease accordingly. Excessive thickness of the casting wall can easily lead to shrinkage and porosity, and it will cause unfavorable factors such as long solidification time and large shrinkage in the die-casting production process, making it difficult to pull out the core and mold.
(2) Selection of wall thickness for die-casting products: Under normal conditions, the wall thickness should not exceed 4.5 millimeters. The suitable wall thickness for small and medium-sized die-casting parts is 1-3 millimeters for zinc alloys, 1.5-4 millimeters for aluminum and magnesium alloys, and 2-4 millimeters for copper alloys.
(3) The wall thickness of die-casting products should be uniform, which is conducive to the simultaneous solidification of the alloy liquid after filling, and can avoid defects such as casting stress, shrinkage, and cracks.
(4) The thick wall part of the fireplace die-casting product structure can be improved by adding ribs or casting embedded parts to enhance its mechanical performance and processability.
(5) The wall of die-casting products should not be too thin. Large areas with too thin walls are prone to defects such as under casting and cold shuts.
The casting of die-casting parts is not very simple. First, the metal needs to be melted, and then the metal liquid that meets the requirements is poured into the mold. After the metal liquid cools and solidifies, it can be processed into the shape and size we want. The process of this casting is casting, but in the process of copper casting, we also need to pay attention to many things.
Die castings can be divided into ordinary sand castings, metal castings, centrifugal castings, continuous casting parts, investment castings, ceramic castings, electroslag remelting castings, bimetallic castings, etc. according to different casting methods. Among them, ordinary sand castings are widely used, accounting for about 80% of the total casting production. And non-ferrous metal castings such as aluminum, magnesium, and zinc are mostly used.
When casting copper alloys first, the metal mold casting method should be used. This method can facilitate the solidification of the alloy and also improve the quality of the die casting. Moreover, it is crucial to avoid defects in castings. If metal grains can be further subdivided, it can facilitate the construction of pores and improve the airtightness of the alloy.
If there is a lot of lead in copper alloys, it is better to use metal mold casting to avoid excessive segregation of copper components. When there are many parts in copper alloys, centrifugal casting can be used. For some larger copper parts, it is better to use low-pressure casting, which can improve the density of die castings. In the process of vigorously improving the performance of die-casting products, it is necessary to fully integrate the development of product productivity, accelerate the improvement of their application performance and quality, enhance their value through correctly driving products, accelerate the reflection of their quality and other aspects of application effects, and reflect the application level of the product with advantages.
Post time: Aug-21-2023