Low pressure die casting and high pressure die casting
The difference between low pressure die casting and high pressure die casting
Aluminum alloy low-pressure die-casting and high-pressure die-casting are two common die-casting processes, with significant differences in pressure, principles, applicable scenarios, etc.:
(1). Pressure range
Low Pressure Die Casting: lower, usually 0.05-0.15MPa (5-15 atmospheres)
High pressure die casting: extremely high, generally 10-150MPa or even higher
(2). Filling method
Low-pressure die casting: The molten metal fills the mold cavity smoothly from bottom to top under low pressure (similar to "pressure feeding")
High-pressure die casting: The molten metal is quickly injected into the mold cavity through the gate under high pressure (similar to "injection")
(3). Process characteristics
smooth mold filling, difficult gas entrainment, and high casting density; but low production efficiency and high cost
fast filling speed, high production efficiency, suitable for mass production; but prone to defects such as pores and shrinkage
(4). Mold requirements
Low pressure die casting: relatively simple structure, high sealing requirements
High-pressure die casting: needs to withstand high pressure, complex structure (including gates, overflow channels, etc.), and higher material hardness requirements
(5). Post-processing requirements
Low-pressure die casting: fewer casting defects and strong adaptability to subsequent processing (heat treatment, welding)
High-pressure die-casting: there may be pores, and it is easy to bulge during heat treatment. Please be cautious in subsequent processing.
What materials are suitable for the two types of die casting?
They are mainly made of aluminum alloy and the specific material selection needs to be combined with the performance requirements of the castings.
L Low-pressure die-casting
materials are mostly alloys with high strength and high density requirements, such as Al-Si-Mg series (such as A356, A357), Al-Cu series (such as 2014), etc.
This type of alloy has good fluidity and can obtain higher strength after heat treatment, making it suitable for scenes that require strict mechanical properties.
H High-pressure die casting
focuses on fluidity and formability, mainly Al-Si series (such as ADC12, YL113).
This type of alloy has a high silicon content (10%-13%), excellent fluidity, and is suitable for rapid prototyping of complex-shaped castings, but its strength is slightly lower than commonly used alloys for low-pressure die casting.
Reasons for performance differences:
High-pressure die-casting materials (such as ADC12) have high silicon content, priority on fluidity but low plasticity, and no heat treatment is required in the cast state to avoid pores causing bulges, such as material C611 that does not require heat treatment;
Low-pressure die-casting materials (such as A356) significantly increase their strength through heat treatment (T6) and are suitable for high-load scenarios.
Data range: The above are typical values. The actual performance will fluctuate slightly due to slight differences in casting process parameters (such as die-casting temperature, pressure) and heat treatment process.
Which scenarios are they applicable to?
Applicable scenarios for low pressure die casting
- Castings that need to withstand higher loads
- Have high sealing requirements
- Require subsequent heat treatment
Applicable scenarios for high pressure die casting
- Castings with complex shapes
- Large batches
- High surface quality requirements but moderate strength requirements
