How to choose steel for die-casting molds? How much is the difference in lifespan under different working conditions?
The selection of steel for die-casting molds directly determines the service life of the tooling. Xinfeng Machinery has compiled mainstream hot work steel parameters to help overseas casting purchasers match working conditions and control mold replacement costs.
1、 Service performance of H13 steel die-casting mold foundation
H13 is the most widely used hot work die steel in the world for die casting molds. After standardized heat treatment, the stability of conventional aluminum alloy die-casting molds can reach 80000 molds. The purity of steel affects the fluctuation of service life, and the high-purity electric slag remelting version has a service life increase of about 32% compared to ordinary refined materials. Most small and medium-sized casting factories in Southeast Asia default to using ordinary H13. Under long-term high-frequency production conditions, the risk of surface cracking increases significantly after 30000 molds.
2、 The performance gap between high-quality hot work steel and ordinary H13
8407 and SKD61 high-purity materials have stronger heat and fatigue resistance. Under the same ADC12 aluminum liquid working conditions, the average number of molds can reach more than 120000, and the purchase price is about 45% higher than that of ordinary H13. From the perspective of full cycle accounting, factories with an annual output of more than 600000 castings can reduce more than 2 mold changes and shutdowns by using high-end steel. Many purchases only compare mold quotations, ignoring the downtime losses caused by steel grades, resulting in higher long-term comprehensive costs.
3、 Logic of steel selection for low-pressure casting molds
The low pressure casting process for aluminum liquid filling has a slow filling speed and lower thermal impact strength, resulting in less alternating stress on the mold steel. Therefore, the requirements for steel grade can be moderately relaxed. The A356 wheel hub low-pressure casting mold can be stably used with high-quality P20 modified steel, and the mold size is generally maintained in the 150000 mold range. The surface of the alloy wheel hub mold cavity needs to be polished, and the impurity content of the steel must be controlled at an extremely low level to avoid pinholes and pitting after polishing.
4、 Special requirements for materials used in metal injection molding molds
The material systems for metal injection molds and aluminum casting molds are completely separated, and MIM molds are exposed to metal feed containing binders for a long time, resulting in prominent dual effects of wear and corrosion. Commonly used stainless die steel such as STAVAX, with a hardness maintained at HRC50-52, suitable for forming stainless steel and iron-based powder parts. This type of mold is usually produced in batches of tens of thousands of pieces, but the difficulty of repairing the wear and tear of the small grooves in the mold cavity is much higher than that of die-casting molds.
5、 Common Misconceptions in Overseas Customer Selection
About 38% of overseas inquiry customers believe that the higher the hardness of the steel, the better. Hot work steel with a hardness exceeding HRC54 has reduced impact toughness and is prone to angular collapse and cracking. Russian speaking and Mexican auto parts customers are prone to this misconception, blindly demanding higher hardness, which actually shortens the lifespan of the mold. When sorting out the plan, Xinfeng Machinery will match the steel and heat treatment process according to the aluminum grade, cycle time, and daily production. The competition for long tail keywords related to steel parameters on B2B platforms is relatively small, making it suitable for independent websites to create content slots.
FAQ
Do H13 molds need to undergo nitriding treatment? Nitriding can improve wear resistance, but if the nitride layer is too thick, it is easy to peel off. It is recommended to control the thickness of the nitride layer to 0.03-0.06mm under die-casting conditions.
Can H13 be used for low-pressure casting wheel hub molds? Sure, but the cost-effectiveness is relatively low, with weak thermal shock under low-pressure conditions, and stable production of mid-range modified plastic mold steel.
Which is more suitable for die casting, SKD61 or 8407? Under the same purity conditions, 8407 has better resistance to thermal fatigue and is suitable for long-term uninterrupted large-scale aluminum die-casting production.
What does electric slag remelting of mold steel mean? The secondary refining process reduces sulfur and phosphorus impurities, minimizes non-metallic inclusions, and significantly delays the initiation rate of hot cracks.
Is cold working steel suitable for aluminum alloy die-casting molds? Not suitable, cold working steel has poor heat resistance and will deform and crack after being exposed to high temperature aluminum liquid for dozens of molds.
Does different aluminum materials have a significant impact on the lifespan of molds? ADC12 has a high silicon content and stronger erosion wear, resulting in a 25% decrease in mold life compared to A356 operating conditions.
What problems may occur if the heat treatment is not in place? Uneven hardness and residual internal stress result in irregular cracking and cavity deformation within a short period of time after mold testing.
What are the requirements for steel in wheel hub mold polishing? Low impurity, high uniformity steel, excessive impurities will show point defects after mirror polishing.
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