Die Casting Heat Treatment: Everything You Should Know
Die casting is one of the common methods used to manufacture metal parts. By learning how heat treatment works, you can improve the strength, durability, and performance of your die-cast products.
Let’s explore what die casting heat treatment is, its types, importance, and the factors that can affect the process.
Overview of Die Casting Process
When you use die casting, you’re shaping metal into specific parts with the help of molds, called “dies.”
First, you melt the metal, then pour or inject it into the mold. Once the metal cools and hardens, you’ve got your finished part.
This process is fast and works well for making detailed parts, like car components or tools. You’ll mostly use metals like aluminum, zinc, or magnesium for die casting.
What is Die Casting Heat Treatment?
Trattamento termico is when you heat your die-cast products to high temperatures and then cool them down in a controlled way to change the metal’s structure.
By using heat treatment, you can improve the strength of your die-cast parts so they can handle more stress, increase their hardness to resist wear and tear, or make them flexible to avoid cracking.
You’ll learn about some common types of die casting heat treatment as you continue reading, so keep going!
Importance of Heat Treatment in Die Casting
Heat treatment is important if you want to get the best performance from your die-cast parts. By heat-treating your parts, you make them tougher and more durable, so they last longer and handle wear and tear more effectively.
It also improves performance by making parts stronger and lighter, which is especially important for industries like automotive and aerospace.
If your parts have problems like cracks or internal stress, heat treatment can fix these issues and ensure they perform as expected.
Additionally, heat treatment gives you control over the properties of your parts– you can make them harder, softer, or more flexible, depending on your needs.
By including heat treatment in your process, you save time, money, and effort by creating parts that are reliable and long-lasting.
Heat Treatment Process for Die Casting
Die casting heat treatment involves several steps to ensure your parts achieve the desired properties. Here’s a simple breakdown of the process:
Step 1: Casting Solidification
First, you inject molten material into the mold at high speed, then cool it quickly. This step, done with die-casting machines, ensures the metal fills the mold completely and solidifies without gaps or structural issues.
Step 2: Solution Annealing
Next, you heat the parts to stabilize their size and shape while removing stress caused during casting. This step, called annealing, is done at temperatures between 450-490°C for a short time. It helps prepare the die-cast parts for further treatments.
Step 3: Quenching
Quenching makes the die-cast parts stronger by dissolving key elements in the material. You heat the die-cast parts to around 500°C for several hours, then cool them quickly in water at 60-100°C. This step increases durability and toughness.
Step 4: Artificial Aging
In the final step, you improve the mechanical properties of your die-cast parts through aging. Aging can be natural (at room temperature) or artificial (at higher temperatures). Here are the 3 types of aging:
1.Incomplete Aging
Done at ~120°C for 3-4 hours, this method increases strength, toughness, and flexibility but reduces corrosion resistance.
2. Complete Aging
Done at ~150-180°C for over 5 hours, it boosts tensile strength but slightly lowers elongation.
3. Over-Aging
Done at ~280°C for over 3 hours, this process improves stress and corrosion resistance.
Types of Heat Treatment for Die Casting
There are several types of heat treatment you can use for your die-cast parts, depending on the properties you want to achieve. Here are the most common types of die casting heat treatment:
T1 (Untreated Artificial Aging)
With T1, your die-cast parts are heated at high temperatures over a certain period of time. You cool the die-cast parts from that process and allow them to age until they reach a stable condition.
Artificial aging is done to speed up the natural aging of materials by exposing them to high temperatures, light, or chemicals.
This method enhances the machinability and surface smoothness of your die-cast parts.
T2 (Solution Treatment)
In this process, you heat the die-cast parts to a specific temperature and hold them at that temperature long enough for the constituents to enter a solid solution.
Afterward, you cool the parts, cold work them to increase strength, and then let them age naturally to a stable condition.
This dissolves certain elements like residual stress or work hardening caused by machining. This method improves the plasticity of the alloy.
T3 (Quenching)
For T3, you first perform a solution heat treatment, then immerse the alloy in a liquid or gas for rapid cooling, which is known as quenching. Cold work the parts and let them age naturally to a stable condition.
This increases the strength and durability of your die-cast parts. This method makes your die-cast parts more resistant to deformation.
T4 (Quenching and Natural Aging)
In T4, you solution heat treat the die-cast parts, quench them, and then let them age naturally.
This method improves the yield strength and the tensile strength of your die-cast parts. The alloy’s hardness gradually increases over time.
T5 (Quenching and Incomplete Artificial Aging)
This type involves solution heat treatment and quenching, then aging the die-cast parts at a lower temperature.
You use this method if you need die-cast parts with high strength and plasticity.
T6 (Quenching and Full Artificial Aging)
In T6, your die-cast parts undergo solution heat treatment, quenching, and artificial aging.
T6 heat treatment is often used in structural applications where parts must not deform under heavy loads like in aerospace, automotive, defense, and marine.
T7 (Quenching and Stabilizing Aging)
With T7, you solution heat treat the die-cast parts, quench them, and then overage them.
This lets you achieve dimensional stability and high strength therefore you can use this type for high-temperature working parts.
T8 (Quenching and Softening Aging)
T8 involves solution heat treating the die-cast parts, quenching, cold working, and then artificially aging them.
This heat treatment is used in products that are cold worked to enhance ductility and dimensional stability.
T9 (Cold Treatment or Cold-Hot Cycling Treatment)
With T9, you solution heat treat the parts, artificially age them, and then perform cold working.
This type of heat treatment process is used to stabilize the dimensions of the die-cast parts.
Factors Affecting Die Casting Heat Treatment Process
When you’re performing heat treatment on die-cast parts, several factors can affect the process and the final results. Here are the things you need to consider:
Selezione del materiale
The type of material you use is very important in how heat treatment works. Different alloys respond differently to heat.
For example, leghe di alluminio require precise temperature control, while steel alloys might need longer durations to achieve the desired properties.
Temperature Control
Controlling the temperature is critical during heat treatment. If the temperature is too low, your die-cast parts might not achieve the desired hardness or strength.
If it’s too high, you risk damaging the die-cast parts or causing unwanted changes in the alloy’s structure. Make sure to use reliable equipment to monitor and maintain the correct temperature.
Time and Duration
The amount of time you heat and cool your die-cast parts directly affects their properties. If you heat the parts for too short a time, the process might not be effective.
On the other hand, heating them for too long can lead to overaging or deformation. Make sure to follow the recommended time for each heat treatment process.
Common Heat Treatment Challenges and Solutions
Sometimes, there are challenges that may arise during heat treatment processes. Here are some common issues you might face and how to solve them:
Uneven Heating or Cooling
If your die-cast parts heat or cool unevenly, it can lead to warping, craps, or inconsistent properties. To fix this, make sure your furnace provides uniform heating.
Additionally, use controlled cooling methods like quenching in a liquid or gas that ensures even temperature distribution.
Distortion or Warping
Thin or complex parts are prone to distortion during heat treatment.
To prevent this, use fixtures or supports to hold your die-cast parts in place during heating and cooling. You can also reduce the cooling rate to minimize stress.
Overheating or Underheating
Incorrect temperature settings can lead to die-cast parts that are too brittle or too soft. Always verify the temperature settings and calibrate your equipment regularly to avoid this problem.
Surface Oxidation
Oxidation can occur when your die-cast parts are exposed to air at high temperatures– causing discoloration or surface damage.
To prevent this, you can use a protective atmosphere in the furnace or apply a coating to protect the surface.
Inconsistent Results
If you’re not getting consistent results, it may be due to variations in material quality or process parameters. Standardize your processes, use high-quality materials, and regularly inspect your equipment to ensure consistent results.
Your Die Casting Parts Manufacturing Expert - DEK
DEK specializes in high-quality die-cast parts and heat treatment services. With advanced technology, skilled experts, custom solutions, and strict quality control, we ensure precision and durability.
Trust us for on-time delivery and expert guidance tailored to your needs. Contatto DEK for reliable, professional die-casting solutions today!
Conclusione
By understanding heat treatment, you can make your die-cast parts stronger, tougher, and more reliable. Choose the right method, control the temperature and time, and fix common issues to get the best results.
With proper heat treatment, your die-cast parts will last longer and perform exactly how you need them to.
