Tooling Material ,Process and Failure Analysis are all common problems in die casting.We can break it down separately.
Tooling Material Process and Failure Analysis–Tooling materials
Aluminum alloy
Commonly used grades are ADC12, YL113, YL102, A380, A360, etc.
Among them, ADC12 is the most commonly used aluminum alloy.
Which has good die-casting formability, machinability and mechanical properties.
Other commonly used grades include ALSi10Mg, ALMg5, etc.
Zinc alloy
Commonly used grades are 3#Zn. Zinc alloy die material is suitable for small die casting production, but the toughness is poor.
Magnesium alloy
Magnesium alloy die materials are suitable for precision die casting molds and mass production, with low density, high strength and good thermal conductivity.
Copper alloy
Copper alloy die material is suitable for high-precision die production, with high hardness and good wear performance.
Steel
Commonly used grades are 45# steel, 50# steel, Cr12MoV steel, etc. Steel die materials with high strength, good toughness and excellent processing properties, suitable for manufacturing large and heavy die-casting molds.
Cemented carbide
Brands are WC-Co, TiC-Ni and so on.
Cemented carbide is used to manufacture surface coatings for cavities and cores to improve wear and corrosion resistance.
Tool steel
Commonly used brands are SKD61, DH-31, 8407, 8418, H13, 3Cr2W8V, 4Mo5CrSiV and so on.
Tool steel mold material has high hardness, wear resistance and fatigue resistance, suitable for the production of high requirements of the mold.
Special steel
Including chromium-molybdenum steel, chromium-vanadium steel, etc., with high hardness and good wear resistance, suitable for manufacturing cold stamping dies.
Cast steel
Commonly used grades are QT550, QT600, S50C, etc.
The casting steel mold material has good wear resistance and corrosion resistance, which is suitable for manufacturing large die casting molds.
Other materials
Including ductile iron, medium carbon steel, etc.
These materials have low manufacturing costs and good compressive properties, making them suitable for making smaller die casting molds.
Tooling Material Process and Failure Analysis–Die casting process
Melting metal
Heating the metal to its melting point, making it liquid.
This step is usually performed in a furnace to ensure that the metal is heated evenly.
Injection of metal
Molten metal is injected into the mold cavity under high pressure.
The injection process requires precise control of pressure and speed to ensure that the metal completely fills the mold and forms the desired shape.
High pressures typically range from 1500 to 25000 psi.
Curing
The metal is rapidly cooled and solidified into a solid in the mold.
This process requires maintaining a certain amount of pressure to ensure that the metal is fully cured and formed into the desired shape.
Demolding
When the metal is fully cured, the mold is opened and the casting is removed from the mold.
This step is usually accomplished using a thimble or other mechanical device.
Trimming
Castings may be removed with excess material such as gates, risers, flashes, and trachomets, which need to be cleaned by dressing tools (e.g., dressing knives) or by hand.
Together, these steps ensure the production of high-quality and precise die castings.
Tooling Material Process and Failure Analysis–Failure Analysis Types
Thermal fatigue cracking
This is one of the most common forms of failure and typically occurs in areas of thermal stress concentration on the surface or inside the mold cavity.
As the number of cycles increases, small holes appear near the crack tip and microcracks gradually form, eventually leading to mold failure.
Integral brittleness
This form of failure is usually catastrophic fracture because of a defective material or improper handling. Integral brittleness often occurs when mechanical or thermal loads are suddenly excessive.
Erosion
The friction and impact of high-speed and high-pressure molten metal and the mold surface will cause the mold surface to wear.
Forming a pit-like irregular surface, and the aggregation is distributed in a granular irregular manner.
Erosion usually occurs at sites where the near-gate temperature is high and the metal hydraulic injection rate is fast.
Dissolution
When the mold comes into contact with the molten aluminum alloy, the chemical reaction produces brittle iron-aluminum compounds, resulting in mechanical abrasion on the mold surface.
Dissolution usually occurs at the point where the mold comes into contact with the molten metal.
Sticking mold
Due to the large temperature fluctuation of the mold surface, the phenomenon of mold sticking, erosion, thermal fatigue and so on is more obvious.
Sticking usually occurs at a higher temperature on the surface of the mold and a slower cooling rate.
Deformation
When the mold is working under high pressure, it is easy to deform due to extrusion and friction. Deformation usually occurs in the weak parts of the mold, such as the gating system, the overflow system, etc.
Cracking
Cracking is usually because impact loads, with mold processing defects and insufficient material properties being the main causes.
Usually occurs in weak parts of the mold, such as gate lines, unpolished parts of the electromachining marks.
Corrosion
When the mold comes into contact with different metal materials, it causes corrosion due to chemical reactions.
Corrosion usually occurs in places where there are soft spots on the surface of the mold.
Such as when the aluminum alloy mold comes into contact with materials such as zinc alloy, magnesium alloy, copper alloy, etc.
Through failure analysis, we can better understand the failure mechanism of molds and castings in the die casting process.
So as to take effective prevention and improvement measures to improve the service life of molds and the quality of castings.
