Squeeze casting, also known as liquid die forging, low-speed and high-pressure process, is a process that combines casting and forging. The alloy fills the mold, solidifies and produces plastic deformation under high pressure. The typical characteristics of the process are low-speed filling and high-pressure feeding and solidification.
Die casting is a metal casting process characterized by applying high pressure to molten metal using a mold cavity. High-pressure and high-speed filling are its typical features. Die casting in this article is limited to high-pressure die casting.
Basic concepts of squeeze casting and die casting
|
Difference |
squeeze casting |
high pressure die casting |
| Typical characteristics of the process |
low-speed filling, high-pressure solidification |
high-pressure, high-speed filling |
| Holding state | Yes, semi-solid to solid state |
No |
|
Internal quality |
dense structure, almost no shrinkage cavities and pores |
coarse grains, pores and shrinkage cavities |
|
Heat treatment |
T6 heat treatment possible |
not possible |
|
Mechanical properties |
close to forging level |
lower |
|
Release agent used |
Powder extrusion casting release agent |
Water-based die casting release agent |
|
Suitable for workpieces |
Suitable for thick parts, not suitable for thin parts |
Both thick and thin parts are acceptable |
|
Machines used |
Extrusion press, hydraulic press |
Die-casting machine |
|
Purpose |
Use aluminum instead of steel and casting instead of forging to reduce weight |
Improve production efficiency. |
|
Typical scope of application |
Structural parts, load-bearing parts |
Motor casing, gearbox, 3C, communications |
Squeeze casting and high-pressure die casting have much higher production efficiency than forging, can be produced in large quantities, have low overall production costs, and can realize more complex products.
The booming development of new energy vehicles determines that the concept of "replacing steel with aluminum and replacing forging with casting" will always be implemented. Steel castings are bound to be gradually eliminated because of their heavy weight and non-environmental protection, and these castings play the role of load-bearing and support. , only when aluminum castings reach the same mechanical properties as cast steel, can they be replaced to ensure normal driving safety. High-pressure die-castings are made of high-speed and high-pressure die-casting, and are destined to have coarse internal grains and many structural defects. Especially pores, keyholes, etc. are produced. Due to its high cost and low efficiency, forging is still not the optimal solution in everyone's mind, even though its forged parts have the best mechanical properties. Squeeze casting not only has the advantages of high efficiency, low cost and large-scale production of casting, but also has the good mechanical properties of forging. It is an important direction for integrated and structured development. However, we must also pay attention to the fact that squeeze casting is not as mature as high-pressure die casting at present. There are also unstable product qualification rates, high initial investment and exploration costs, immature upstream supporting consumables, etc. For example, the required release agent consumables generally have to be powdered. A water-based release agent that can withstand high temperatures for a long time and maintain good release performance.
Regarding the prospects of high-pressure die-casting, in addition to the fields involved in squeeze casting, workpieces produced by high-pressure die-casting can basically replace steel castings, and Tesla's concept of integrated molding has become the goal pursued by the entire industry. Lijin and Yizumi , Haitian ultra-large die-casting machines set new records time and time again, and die-casting will also move towards a higher direction in the future.