- 21 December 2024
Casting is the oldest metallurgical technique known to us. The first functional metal elements were accidentally refined copper from chalcopyrite and chalcocite rocks. The metal could be cast into ingots and given a useful shape. Aluminum casting is an extremely important method for producing parts of any shape. The shape is usually obtained in a one-step process from liquid metal to finished or nearly finished parts. In this article, we will discuss what aluminum casting is, how it works, its importance, types and uses.
What is the casting process?
Aluminum casting is the process of introducing molten aluminum into a cavity so that the metal can obtain a specific shape. Aluminum and many of its alloys have a relatively low melting point and low viscosity when melted, yet it quickly takes on a specific shape. Aluminum foundries take advantage of these properties by creating a heat-resistant cavity (in one or two parts) into which molten aluminum is poured. The metal then cools and hardens, taking on the shape of the cavity it has filled. This process allows aluminum to be used more efficiently in industry.
Aluminum casting is probably the most important technology that gives such importance to aluminum in industry. Aluminum is the third most common element in the Earth's crust. It is easy to find and easy to refine. Aluminum is the key to most technologies, and the aluminum casting process is one of the key processes that bring the material into widespread use and recognition.
Aluminum used in casting generally refers to its alloys, not pure aluminum. Which have the following properties:
- Aluminum castings have a higher yield range, generally lower than pure aluminum metal, which is very soft.
- Ultimate tensile strength (UTS) varies widely from process to process. Where low porosity is achieved by aggressive degassing of the alloy and high-pressure casting, the UTS approaches the alloy's optimum. Some alloys have been developed to be more resilient, while others have been developed to be more rigid, which means they are more prone to brittleness.
- Aluminum castings have an exceptional stiffness-to-weight ratio. A better one is obtained only with magnesium or titanium.
- High corrosion resistance is normal for cast aluminum parts.
- Excellent electrical and thermal conductivity.
Tensile strength depends on the type of alloy, with pure aluminum having the worst indicators here. For example, pure aluminum has a tensile strength of 90 MPa, while casting alloy A07130 has a value of 221 MPa. Aluminum foundries today offer products that are tailored to the expectations and needs of the customer.
A separate issue is how much the casting process increases or decreases the durability of aluminum.
Aluminum castings are very durable if they are designed to take advantage of the alloy's strengths and balance the weaknesses of the process. Aluminum castings are susceptible to stress cracking, abrasion and impact loads, all of which need to be considered in the design of the final product.
Aluminum casting is generally resistant to heat. However, the magnitude of this resistance varies greatly from alloy to alloy. Some alloys can be cast easily, resist heat cracking and withstand temperatures up to 180 ° C. Others can withstand temperatures of 350 ° C, but require simpler shapes and thicker sections for casting. Much depends on the casting process used. The most common is pressure casting, sand casting or permanent mold casting. Die casting ranges from simple hand-poured tools to fully automated systems for very large volumes.
