Views: 0 Author: Site Editor Publish Time: 2025-09-09 Origin: Site
Aluminum squeeze casting,also known as liquid die forging, is a composite forming process that combines the characteristics of casting and forging. It achieves high-quality castings with dense internal structure and mechanical properties close to those of forgings by applying extremely high mechanical pressure, causing the molten metal to solidify and take shape under pressure.
I. Core Principles and Process
The core of squeeze casting lies in "slow solidification under high pressure".
Basic process flow：
1. Melting and quantitative pouring: Melt the aluminum alloy to the predetermined temperature, and then use the quantitative pouring system to pour the precise amount of liquid aluminum into the preheated lower mold cavity.
2. Mold closing and pressurization: The upper mold rapidly descends to close the mold and applies an extremely high unidirectional static pressure to the molten aluminum inside the mold (the pressure is usually much higher than that in traditional die casting, reaching 50-150 mpa or even higher).
3. Pressure holding and solidification: Pressure will be continuously applied and maintained for a period of time until the molten aluminum is completely solidified under high pressure. This stage is the key to obtaining dense tissues.
4. Mold opening and ejection: After depressurization, the mold is opened and the finished casting is ejected from the mold using the ejection mechanism.
5. Post-treatment: Remove the gates, risers and flash. If necessary, perform T6 heat treatment.
II. Main features and advantages
Compared with the traditional die-casting process, squeeze casting has the following significant advantages:
1. Extremely high casting density: High pressure forces the molten metal to contract, eliminating shrinkage cavities and porosity caused by solidification and contraction, while also inhibiting gas release. There are no pores inside the casting, and the structure is dense.
2. Excellent mechanical properties: Due to its dense structure, the mechanical properties of squeeze castings (especially elongation, impact toughness and fatigue strength) are much higher than those of traditional die-castings, and can even reach or approach the level of forgings.
For instance, after squeeze casting and T6 treatment, the tensile strength of A356 alloy can reach 300-350 mpa, and the elongation can exceed 10%.
3. Heat treatment is possible: As there are no shrinkage inside, castings can undergo heat treatments such as solution treatment (T4) and artificial aging (T6), thereby maximizing their mechanical properties. This is something that traditional die-castings cannot achieve.
4. Excellent dimensional accuracy and surface quality: Formed in metal molds, the product has a high surface finish, stable dimensions, and small machining allowance.
Limitations：
1. Large equipment investment: Large-tonnage dedicated squeeze casting machines are required. The molds need to withstand extremely high pressure, with high rigidity and strength requirements, resulting in high costs.
2. Low production efficiency: Due to its characteristics of "slow injection and long holding time", the production cycle is longer than that of traditional die casting.
III. Compared with traditional die-casting and forging forming
Features | Squeeze casting | Die casting | Forging |
Principle | Liquid metal solidifies slowly under high pressure | Liquid metal is filled and solidified at high speed under high pressure | Solid metals undergo plastic deformation under high pressure |
Internal quality | Excellent, no shrinkage porosity, and dense structure | With shrinkage porosity and loose structure | Best,the streamline is complete and the internal structure is dense |
Mechanical property | Excellent, approaching the level of forgings | Average,low elongation and fatigue strength | Best |
Heat treatability | Full heat treatment of T6 is acceptable | Solution treatment is not feasible | Heat treatment is usually required. |
Production efficiency | Average | High | Low |
Costs | The cost of molds and equipment is high | The cost is relatively low | The cost of molds and equipment is extremely high |
IV. Key application fields
Squeeze castings are mainly used in fields where there are extremely high requirements for safety, reliability and mechanical properties.
1. Automotive Safety and structural Components (Core application areas) :
Chassis and suspension system: steering knuckle (control arm), wheel hub, suspension link, caliper body. These components require extremely high fatigue strength and reliability.
New energy vehicles: Battery pack trays/shells (requiring high sealing performance, high rigidity, and impact resistance), motor drive shells, and electronic control system shells.
Braking system: Brake booster housing.
2. Aerospace and Military Industry
Non-primary load-bearing structural components with strict requirements for weight and performance, such as brackets, shells, and unmanned aerial vehicle parts, etc.
3. High-performance sports equipment
Bicycle frames, motorcycle wheels and engine components, mountain climbing equipment fasteners, etc.
4. Other industrial fields:
High-pressure pneumatic/hydraulic valve bodies, pump casings, compressor components and other parts that need to withstand high pressure and high fatigue.
V. Conclusion
Aluminum squeeze casting is a high-end forming process that is "quality-oriented". It perfectly fills the gap between traditional die-casting (which emphasizes efficiency) and forging (which focuses on performance but is costly and has shape limitations). With the development of the industry, squeeze casting capable of producing high-performance and highly reliable structural components will play a significant role and become an important part of advanced manufacturing technology.
