Metallurgical experts prefer die-casting since it reduces the production cycle, decreases costs, and crafts premium and accurate casts. Moreover, many times it reduces the postproduction machining needs.
Despite the ability of a die casting machine to handle a wide range of metals, some casts are difficult to make. So companies use various alloys that are easier to die-cast but provide the same strength.
Classes of Alloys According to Melting Points
Before getting into the details of alloys, let’s first examine their division for melting points.
Lower Melting Points: The metals that have melting points less than 385°C (725 F) fall in this category. For instance, zinc, tin, and lead-based alloys.
Slightly Higher: Metals with melting points in the range of 426°C to 482°C (800 – 900 F) fall in this class. Zinc Aluminum alloys have melting points in this range.
Moderate melting points: The moderate melting class mainly comprises aluminum and magnesium alloys with a melting range of 621°C - 704°C (1150 F – 1300 F).
High melting points: Lastly comes the class of high melting points alloys. These are copper alloys having melting points over 899°C or 1650 F.
Commonly Used Alloys for Die Casting
Zinc materials are relatively easy to die cast. Variation in tin and copper concentration makes the alloy flexible and rigid. Its rigidity makes it a good substitute for brass and cast iron. Since zinc alloys are not fit for force exceeding 17,000 pounds per inch. Therefore, they are not fit for high mechanical applications.
Lead alloys have high resistance against corrosion. Therefore, they are widely used for electroplating various other metals. Mostly, they have applications in decorative golds, bearings, wheels, etc. Their castings are sturdy with an endurance capacity of 8000 pounds of force per square inch.
Aluminum alloys come in handy for products requiring good dimensions and mechanical properties. For instance, the AL alloy 413 is best for high-pressure endurance and viscosity, and 390 is a perfect fit for toughness and resistance properties.
Some Things to Factor in When Choosing an Alloy for Die Casting
The first and foremost thing to consider is the alloy cost since they fluctuate with the market. However, aluminum has a relatively low cost per cube hence it is widely used in die-casting.
Strength and Impact Resistance
This metric depends on the nature of your project. If you want to die-cast materials of good strength, pick a metal with the highest modulus of elasticity. Normally, zinc alloys are used for their high endurance.
Some metals are vulnerable to oxidation leading to rust and corrosion. Ensure to pick a metal with the highest resistance. Adding copper alloys to your die cast increases its corrosion resistance.
Die casting alloys made their way when manufacturers realized that molding hard-core metals such as pure steel was not economic. Therefore, there began research for metals that offered similar strengths yet feasibility.
The alloy you choose depends upon the project at hand. However, conventionally, it is best to look into the chemical strengths and weaknesses of the compounds and the price per cube before a purchase.