Low-Pressure Casting: Specific Steels for Efficiency and Quality

In the light alloy foundry landscape, low-pressure casting is a strategic process, especially used for producing castings with thick sections. This method is distinguished by its high quality but poses a crucial challenge to productivity: heat dissipation. The choice of the right die steels thus becomes a decisive factor. Parameters like the steel’s thermal conductivity and toughness determine the material selection, whether it’s a standard grade like 2343 (H11) or a more advanced one, directly impacting the process’s efficiency.

Low-pressure casting is valued for the quality advantages it offers. The resulting castings are characterized by high density and excellent surface quality, as the controlled filling of the mold prevents oxidation. However, the process’s economic efficiency (yield) is largely determined by the casting’s solidification time. To achieve high production frequencies, rapid heat dissipation is imperative. This is where the die steel plays its fundamental role. Bonomi Acciai, as the Italian partner of Swiss Steel, has a complete portfolio of hot-work tool steels, designed to meet the diverse needs of this process.

While conventional steels like Thermodur 2343 (H11) and 2344 (H13) offer a good basic balance, more demanding applications require specific solutions. The analysis focuses on two premium grades:

For high-frequency production, the primary goal is to reduce cycle time. This is achieved by maximizing heat removal from the casting.

Our premium brand, Thermodur® 2383 Supercool, was specifically developed to synergistically improve two key properties: thermal conductivity and thermal fatigue resistance.

As the comparative graphs show, this material has drastically superior thermal conductivity (green line) compared to all other grades. At the same time, in cyclic thermal fatigue tests, it shows almost zero crack depth (green line) even after 8000 cycles, outperforming all other steels.

When castings have complex geometries or significant wall thicknesses, the die is subjected to severe mechanical and thermal stress. In this scenario, toughness becomes the priority parameter.

Thermodur® E 40 K Superclean responds by offering an excellent combination of hot strength and exceptional toughness at high temperatures. This makes it particularly suitable for complex castings and thick-walled parts.

The following table, based on technical data from the brochure, summarizes the performance of the main steels used in low-pressure casting:

The choice of steel for low-pressure casting is not one-size-fits-all; it depends on the primary goal of the process. To maximize productivity and reduce cycle times, Thermodur® 2383 Supercool offers unparalleled thermal conductivity. To ensure maximum durability and reliability with complex castings, Thermodur® E 40 K Superclean is the solution with the highest toughness.