Sandvik launches hot-work tool steel powder

Sandvik has introduced Osprey HWTS 50, a lean hot-work tool steel powder designed for enhanced printability. Primarily developed for laser-based additive manufacturing (AM), it is also well-suited for hot isostatic pressing (HIP) and metal injection moulding (MIM). Tempering and thermal fatigue resistance as well as thermal conductivity are improved compared with conventional H-class hot work tool steels. These advanced properties effectively address many common challenges in hot-work applications within general engineering.

Osprey HWTS 50 improves the processability in laser powder bed fusion (L-PBF), lowering the susceptibility of cold cracking compared with conventional H-class hot work tool steels. Typical applications include high-pressure die casting dies, injection molds, and hot forming tools.

The chemical composition is tailored for improved hot hardness at temperatures exceeding 600°C. It is characterised by lower carbon content compared with those of medium carbon hot work tool steels and modifications to the carbide forming elements to ensure a comparable or even enhanced tempering resistance despite the lower percentage of carbon.

The thermal conductivity of Osprey HWTS 50 is also higher compared to medium carbon tool steels over a wide temperature range. High thermal conductivity is beneficial for applications running at elevated temperatures, such as die casting and forging. It ensures rapid and efficient heat dissipation, resulting in faster cycles.

Fabrication challenges
Faraz Deirmina, Sandvik’s principal metallurgist in metal powder, said: “AM is increasingly being used to produce tools and dies with near-surface conformal cooling channels. Besides optimising processing parameters, it is important to develop chemistries specifically tailored for this technology to address fabrication challenges. Osprey HWTS 50 is designed to alleviate these challenges making it highly suitable for tooling applications at elevated temperatures. Examples are hot forming dies, extrusion and injection moulding dies, and high-pressure die-casting dies.”

Osprey HWTS 50 metal powder is manufactured by either induction melting under Vacuum Inert Gas Atomisation (VIGA) or melting under argon prior to Inert Gas Atomisation (IGA), producing a powder with a spherical morphology which provides good flow characteristics and high packing density. In addition, the powder has a low oxygen content and low impurity levels, resulting in a metallurgically clean product with enhanced mechanical performance.

With the alloy design philosophy behind HWTS 50, Sandvik is contributing to a more sustainable future in several ways. By using leaner compositions optimised through computational tools, it increases resource efficiency and extends the lifetime of components, which in turn reduces energy consumption and CO₂ emissions. Additionally, computational tools enable faster and more eco-friendly alloy development with optimised chemistries, outperforming traditional trial-and-error methods.

Sandvik currently has a patent pending for Osprey HWTS 50 covering the composition of the alloy.