Treatment method for leakage of aluminum castings:
1. During the hot stamping stage, analyze whether there is local air entrainment and poor fusion of alloy flow in the pressed aluminum casting. Properly add slag collection bags and exhaust ducts;
2. The far end or wall thickness of the component is not compacted. Increase specific pressure;
3. Select good alloys;
4. Use X-ray inspection to identify the hot junction. If the heat junction is indeed a leakage point, it can be negotiated with the customer engineer to modify the structure at that point and reduce the wall thickness. In addition, the secondary extrusion process can also be used to solve the leakage at the pyrolysis site;
5. It can be judged based on simulation filling or actual sample debugging analysis. Correctly improve the pouring system;
6. Try to avoid processing or use the smallest possible machining allowance;
7. X-ray inspection of the internal quality of pressed aluminum castings. Use coatings with low gas generation capacity; Impregnation treatment of pressed aluminum castings;
8. Identify pressure testing equipment using qualified aluminum castings. Maintenance and inspection equipment;
9. Flatness inspection can reveal. Control the production process and ensure sufficient pressure holding time. Prevent squeezing during process operation;
10. It can be found through pressure testing. Increase process protection and timely repair of molds;
11. X-ray inspection of the internal quality of pressed aluminum castings. Reduce the melting temperature appropriately;
Aluminum castings are very good. After multiple tests, it has been proven that aluminum products have excellent resistance to wind pressure and weathering, and their resistance is astonishing. Therefore, if we use pressed aluminum castings, we will add them. At the same time, the weight of aluminum castings is relatively light, which can reduce the burden on people and also reduce the danger.
Due to the excellent toughness of aluminum, it determines its plasticity and can be designed into various shapes. Ductility is particularly advantageous. It is precisely because of this that aluminum castings can be used for recycling, saving materials, and expanding their application range.
Processing steps of aluminum die castings
1. What is timeliness processing? The method of heating the solid solution treated casting to the set temperature, lasting for a period of time, and then slowly cooling it in air is called aging. If aging is completed at room temperature, it is called natural aging. If aging is completed in an environment higher than room temperature and held for a period of time, it is called artificial aging. Aging treatment undergoes a spontaneous process of decomposition of supersaturated solid solutions, which can restore the lattice of the alloy matrix to a relatively stable state.
2. What is solid solution treatment? Heat the casting to almost the melting point of eutectic, then continue at this temperature for a longer time, and then cool it to allow the components to dissolve well. Store this high-temperature state until room temperature, and this process is called solid solution treatment. Solid solution treatment can enhance the strength and plasticity of castings, and enhance the ability of alloys. The effect of solution treatment is usually related to three aspects: solution treatment temperature, solution treatment insulation time, and cooling rate.
3. What is annealing treatment for? The process of heating aluminum castings to typically around 300 ℃, holding them for a period of time, and then cooling them to room temperature in the furnace is called annealing. During annealing, the solid solution will decompose and the phase particles will aggregate, which can remove the internal stress of the casting, keep the size of the casting stable, avoid deformation, and enhance the plasticity of the casting.
Die aluminum castings have good strength and can be heat treated to obtain good mechanical, physical, and performance, therefore they are widely used in mechanical manufacturing. So what should be paid attention to when welding aluminum castings?
1. During the welding process of aluminum and aluminum alloys, a large amount of heat can be transmitted to the interior of the base metal. Therefore, when welding aluminum and aluminum alloys, a large amount of energy is consumed in other parts of the metal. In order to obtain welding joints, it is advisable to use energy concentrated, high-power energy or preheating and other process measures as much as possible.
2. Aluminum has a good ability to reflect light and heat, and there is no significant change in luster during solid and liquid transition. It is difficult to determine during welding manipulation, and alloy elements are prone to evaporation and burning, resulting in a decrease in weld performance.
3. Aluminum is prone to oxidation in the air and during welding, and the melting point of aluminum oxide is high, stable, and difficult, hindering the melting and fusion of the base material. The oxide film on the surface of aluminum and the large amount of water adsorbed can easily cause porosity in the weld seam. Before welding, aluminum castings should undergo strict surface cleaning using chemical or mechanical methods to remove the oxide film on their surface.
4. Aluminum and aluminum alloys can dissolve a large amount of hydrogen in the liquid state, while hydrogen is almost insoluble in the solid state. During the solidification and cooling process of the welding molten pool, hydrogen cannot overflow in time, which can easily form hydrogen pores. Strictly controlling the source of hydrogen can prevent the formation of pores.
5. The volume shrinkage rate during aluminum solidification is large, and the deformation and stress of welded aluminum castings are large. Therefore, measures to prevent pre welding deformation need to be taken. When the base metal of the base metal undergoes deformation or solid solution aging, the welding heat will cause a decrease in the strength of the heat affected zone. During production, measures such as adjusting the composition of welding wires and welding process can be taken to prevent the occurrence of thermal cracks.
Post time: Aug-30-2023