QuesTek Innovations LLC, a leading developer of new metal alloys and powders, has announced a stainless steel composition for powder bed fusion additive manufacturing (AM) for use either in the as-printed condition or with a single low-temperature heat treatment. This development is significant because it allows for production of complex, high-strength stainless parts via AM, comparable to wrought 17-4 PH, but without the need for expensive cryogenic processing or high-temperature heat treatment. The project has been funded by the US Navy Small Business Innovation Research program.

Commonly used 17-4 steel in AM often requires higher-cost argon-atomized powder to avoid retained austenite issues and it yields poor properties; however, even properties of argon-atomized 17-4 properties fluctuate widely and are sensitive to the feedstock composition.

Commenting on this development, Dr. Dana Frankel, QuesTek Manager of Design and Product Development said "With QuesTek's QT 17-4 powders, a fully martensitic microstructure is achieved in the as-printed condition. The high temperature solution heat treatment process, required for conventional 17-4, is not needed for QuesTek's alloys, and the resulting properties have less variation."

Two feedstock options are available: QT 17-4 for use in the direct aged condition and QT 17-4+ for use in the as-printed condition. The corrosion resistance and fatigue performance of both designed AM alloys is equivalent or improved over AM material printed using commercially available 17-4 powders.

Although QuesTek's initial effort has focused on powder-based AM, it plans to demonstrate in one or more wire-based AM processes to enable larger component production at lower cost.

QuesTek's new 17-4 powders can be used in a wide range of industries, including aerospace, defense, medical, chemical processing and energy. QuesTek's powder was developed using its proven Integrated Computational Materials Engineering (ICME) technologies and Materials by Design® approach.

QuesTek is in discussions with commercialization partners including alloy producers, metal AM machine manufacturers and service bureaus to license these technologies and accelerate commercial adoption.

The QT 17-4 and QT 17-4+ powders are among a series of alloys QuesTek is developing for high performance, production-quality additive manufacturing applications.