Taking Notice Of Design Aluminum And Aagnesium Alloy Castings Construction
2015-07-21 huqiong 118
When the meter aluminum and magnesium alloy castings structure, usually should note the following:
1. Since the melting point of aluminum and magnesium alloys low, you can use a variety of methods for producing cast aluminum and magnesium alloy castings. Therefore, in the design of their structures, the first of which should be considered in the foundry casting casting method in order to consider the appropriate structure manufacture ability.
2. Aluminum and magnesium alloy castings should maximize the use of thin-walled structure, and strive to uniform thickness, which are beneficial for the prevention of shrinkage, improve the strength of the casting metal. But uneven thickness need to set riser feeding aluminum and magnesium alloy castings, also some parts with thick, coagulated order to achieve favorable feeding, to ensure quality.
3. Easily oxidized aluminum and magnesium alloy intake, low density (specific steel, cast iron small 2/3 to 3/4 ) so that the metal hydrostatic pressure is small, it is difficult exhaust. Thus aluminum and magnesium alloy castings easy to produce porosity and oxide slag, reduce the mechanical properties and air tightness, avoid large horizontal casting structure design, the transition to be smooth without causing the molten metal turbulence.
4. Due to the low melting point of aluminum and magnesium alloy, for a certain tightness requirements of casting, special attention to consider avoiding the use of the chaplet should be fixed in the core design of the casting structure, otherwise the chaplet and the casting body is not fusion and oil will spill leak.
5. Since aluminum and magnesium alloy wire shrink large low modulus of elasticity, sensitive to local stress concentration, and therefore easy to use in the casting and deformation and cracks, to this end should also be noted in the casting structure design:
a. The use of a large inertia-shaped, box-section geometries and shapes to enhance the casting wall.
b. Structure and shape of the ribs should be appropriate, or at the edge of the rib is easy to produce stress concentration, in addition, the ribs should not be too thick, otherwise in connection with the wall Shrinkage easy to produce.
c. To avoid the edge of the hole should focus should be generating an enhancement, such as using the knurled strengthened.
d. The Wheel castings used to strengthen the reinforcing ribs connecting the hub and spokes, often used between the casting wall thickened walls tapered connection.
e. Can be used for thin-walled castings ribs or stepped cross-section to be strengthened; mutual Avoid distant large diameter bolt aluminum and magnesium alloy castings, otherwise it will be too large because the local force generated by Zhai shadow more reasonable. casting design should be used more number of small diameter bolts to fasten the cast, so each bolt fastening force slug: not to make softer aluminum and magnesium alloy casting deformation, also through the use of larger nuts washers to reduce the pressure on the nuts.
g. As far as possible along the axis of the force suffered the casting transfer, in order to avoid additional bending or torsion stress; inch thin-walled shell-shaped aluminum and magnesium alloy castings, should not have mutated shape.
6. Magnesium alloy compression ratio of high tensile strength, so the design of magnesium alloy castings structure, should adopt asymmetric section and box it to withstand stress.
7. Poor corrosion resistance of magnesium alloy, commonly used surface treatment to improve the corrosion resistance of magnesium alloy castings, in addition to casting structure design should pay attention to: the use of water in contact with the magnesium alloy castings ( such as pumps casting) can save as much as possible to avoid water pits, to prevent corrosion of the paint was destroyed, there should be no sharp corners on the casting.
8. Should be noted that double metal casting, casting and other embedded solutions to aluminum and magnesium alloy casting structure design problems.
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