1. Optimize mold structure design (source control)
Channel design: Adopting a tapered channel design to avoid sudden changes in flow cross-section and sharp turns. A sufficiently large R angle is designed at the turning point to reduce turbulence and eddies. The use of fan-shaped sprue design can evenly distribute the flow of molten metal and reduce local high-speed zones.
Upper limit control of sprue speed: Control the sprue speed within the safe range allowed by the material (aluminum alloy generally recommends an upper limit of 40-60 m/s), and take the lowest value possible while meeting the filling quality requirements.
Cooling water channel layout: Install cooling water channels in high erosion prone areas (such as sprues, core flow surfaces, etc.) to achieve rapid local heat dissipation.
2. Optimize process parameters
Slow injection control: The critical slow injection velocity (~0.2 m/s) is used to minimize the initial velocity while ensuring acceptable low-speed entrainment, in order to reduce the risk of cavitation and erosion.
Mold thermal balance management: Control the overall temperature distribution of the mold, ensure a small temperature difference on the surface of the mold cavity, and avoid local overheating becoming a breeding ground for corrosion and chemical reactions.
3. Optimal selection of mold materials and heat treatment
Material selection: Hot work die steel with high thermal fatigue resistance, high red hardness, and good resistance to tempering softening is used. H13 is the most commonly used option; For occasions with higher requirements, DIEVAR and SKD61 can be chosen.
Heat treatment process: By optimizing heat treatment methods such as nitriding, nitrogen carbon co diffusion, PQP treatment, etc., the thermal hardness and erosion resistance of the mold surface can be improved.
4.Surface coating (the most effective protective measure)
Modern surface treatment technology has become one of the most core and direct means to suppress erosion
Nitriding+Coating Composite (Duplex Treatment): First, plasma nitriding is performed to obtain a high hardness support layer, while removing the white layer to enhance the adhesion with the coating. Then, a high-temperature resistant and erosion resistant nanostructured coating (such as AlCrTiN) is deposited. This composite solution can increase the lifespan of aluminum alloy die-casting molds by up to 500%.
Physical Vapor Deposition (PVD)/Ionic Coating: A ceramic film (such as CrN, TiAlN, etc.) that does not react with metals such as aluminum and magnesium is deposited on the surface of the mold, completely isolating the contact between the metal liquid and the mold substrate. The coating failure resistance can reach above 900 ℃.
Anti adhesion and erosion resistant composite coating: multi-layer design, including bonding layer (W), wear-resistant and erosion resistant layer (W/WC Co), and anti adhesion layer, can effectively reduce mold sticking and resist erosion damage
