ORNL Combines 3D Printing and HIP to Create Large Metal Parts

As the demand for large-scale metal parts continues to rise across sectors such as clean energy, aerospace, and defense, the Department of Energy’s Oak Ridge National Laboratory (ORNL) is spearheading research, supported by the Metal Powder Industries Federation and the Electric Power Research Institute, to re-establish U.S. manufacturing dominance in this area. Through advancements in powder metallurgy-hot isostatic pressing (PM-HIP), paired with additive manufacturing (AM) techniques, ORNL is offering what it considers a high-precision alternative to traditional casting and forging methods.

With conventional casting and forging capabilities having largely shifted overseas, the U.S. faces supply chain challenges for components exceeding 10,000 pounds. ORNL’s research is exploring PM-HIP as a solution, leveraging 3D printing for enhanced process control and geometric complexity. The process involves fabricating pre-formed molds—or “cans”—using wire arc additive manufacturing (WAAM) and hybrid additive-subtractive methods, which are then filled with metal powders.

The sealed molds undergo heating and pressurization cycles in a hot isostatic press (HIP). Unlike traditional methods, this solid-state bonding process consolidates metal powders into dense, complex geometries without melting, allowing for tighter tolerances and reduced porosity. This approach not only offers design flexibility but also opens the door for multi-material builds, critical for applications in sectors with stringent performance requirements.

PM-HIP’s ability to produce high-integrity metal parts domestically could help the U.S. reduce its dependency on foreign suppliers, a crucial step in enhancing supply chain resilience. For the nuclear, hydroelectric, and aerospace sectors, PM-HIP provides a method to manufacture large, complex components like pressure vessels and impellers with enhanced material properties, such as improved toughness and resistance to thermal fatigue.

ORNL’s advancements align with the U.S. Department of Energy’s focus on decarbonization. The PM-HIP process enables the use of high-performance materials in energy generation and distribution infrastructure, supporting the transition to more efficient, lower-emission systems. The potential to locally produce such components can also reduce the carbon footprint associated with overseas transport and extended supply chains.