Christian Everett everything is possible. Reason one: price of one tone of H11 steel is around 700$. Tungsten alloy is around 35000$.

Reason Two - how to machine surface of Tunsten alloy? according to drilling date - Tunsten alloy machining time is around 10-30min / 100mm but H11 is around 3-10min / 100mm

But everything should be calculated: for what puprose do you need it and will you get a good profit

In conclusion, molten metal injection molding using a tungsten mold isn't currently practical due to material handling, equipment, and solidification control challenges

Injecting molten metals such as aluminum and stainless steel into a mold to directly produce finished parts, as opposed to using metal injection molding (MIM) with powdered metals, is indeed a possible concept, and it actually aligns more closely with the principles of die casting or investment casting, where molten metal is injected into molds to form parts.

Here’s a breakdown of the concept and some key considerations:

1. Molten Metal Injection into a Tungsten Mold:

Molten aluminum and stainless steel can theoretically be injected into a mold in their molten state, provided the mold material can withstand the high temperatures and thermal stresses involved.

Tungsten is a good candidate for the mold material due to its high melting point (around 3422°C), high thermal conductivity, and resistance to corrosion. These properties would allow tungsten to handle the high temperatures of molten metals like aluminum (~660°C) and stainless steel (~1370°C) without deformation or failure.

However, the mold design would need to ensure effective heat dissipation and thermal management. Tungsten has excellent thermal conductivity, which could lead to rapid cooling of the molten metal and potentially cause solidification issues, so mold design would need to optimize cooling rates.

2. Challenges:

Tungsten Molds: Tungsten’s high cost and difficulty to machine (due to its hardness) are important practical considerations. While it’s a good candidate from a thermal perspective, the cost and manufacturing complexity might make it less viable for high-volume production compared to other metals like steel or aluminum, which are commonly used in conventional die-casting processes.

Metal Viscosity and Flow: The viscosity of molten aluminum and stainless steel is a critical factor. Aluminum has a relatively low viscosity compared to stainless steel, making it easier to inject, but stainless steel may require higher pressures or more advanced injection systems to ensure smooth flow into the mold.

Mold Design & Injection Pressure: The injection system would need to be designed to handle the pressures required to inject molten metal into the mold cavity. This includes considering the need for high-pressure pumps, valves, and possibly special gating systems to manage metal flow.

3. Alternative Approaches:

Pressure Die Casting: Molten metal is injected into a steel mold under high pressure to form parts. While this process is well established for aluminum and some alloys, stainless steel is much more challenging because of its higher melting temperature and the greater wear it would impose on the mold. However, high-pressure die casting (HPDC) of aluminum is a very common technique.

Investment Casting: This process involves creating a mold around a pattern (often via a ceramic shell), melting and removing the pattern, and then pouring molten metal into the shell. Stainless steel and other high-temperature metals can be cast in this manner, although it is a more time-consuming process than die casting.

Lost Foam Casting: A method where a foam model is coated with a refractory material, and molten metal is poured directly into the cavity. While this is also used in the foundry industry, like investment casting, it’s slower and may not be ideal for high-volume production.

4. Potential Benefits and Drawbacks:

Benefits:

Direct injection of molten metal eliminates the need for powder production and sintering, potentially reducing some steps in the production process.

The process could enable high precision and complex geometries.

It may allow for a more consistent microstructure in the final product due to the molten metal’s uniform flow into the mold.

Drawbacks:

The high cost of tungsten molds could offset any savings gained from eliminating sintering and powder production.

The process may still face challenges with cooling rates, metal flow, and the risk of defects such as porosity or incomplete filling in intricate designs.

Stainless steel’s higher melting temperature would present additional engineering challenges compared to aluminum alloys.

Conclusion:

It is technically feasible to inject molten aluminum and stainless steel into a tungsten mold to create parts, but it would not necessarily be a "drop-in" replacement for metal injection molding (MIM) processes. This approach would require careful engineering to address issues such as mold material cost, mold durability, metal flow dynamics, and the cooling process. While this method could reduce the steps involved in MIM (e.g., no need for powder sintering), the challenge lies in overcoming the complexity of high-temperature processing and ensuring consistent part quality.

If high-volume production is the goal, other established techniques such as die casting for aluminum or investment casting for stainless steel might still be more cost-effective and practical.