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Tech Front: New High-Hardness Metal-Matrix Material Developed for Additive Uses

 

A new ferrous metal-matrix material developed by The NanoSteel Co. (Providence, RI) will soon offer manufacturers a new alternative for producing fully dense, high-hardness metal components with additive manufacturing techniques.

A developer of engineered powders and metal alloys, NanoSteel announced Sept. 24 that it had successfully leveraged its uniform metal-matrix microstructures in a laser-sintering process that enabled creation of a crack-free, fully dense bulk sample. The company’s initial focus in additive manufacturing will support the need for on-demand, on-site wear parts, while addressing challenges in 3D printing of high-hardness parts.

This materials breakthrough overcomes a major hurdle—the tendency to develop cracks during part builds—in creating a high-hardness metallic part through additive manufacturing processes. To achieve the fully dense, crack-free material, NanoSteel said it worked with a global process development partner to optimize processing of a proprietary NanoSteel alloy with a high-volume fraction of borocarbide phases.

The resulting material successfully produced a fully dense (99.9%) crack-free part with hardness values over 1000 HV, wear resistance comparable to conventionally manufactured M2 tool steels, and a uniform microstructure. These properties were achieved without the need for postprocessing, such as hot isostatic pressing (HIP) or further heat treatment, reducing production cost and lead times.
A new additive material from The NanoSteel Co. is a fully dense, crack-free metal with hardness values over 1000 HV.
“Currently, the material options to produce highly wear-resistant parts through additive manufacturing are limited,” said Harald Lemke, NanoSteel’s general manager, Engineered Powders. “By extending the reach of steel into markets currently served by WC-Co, ceramics, and other nonferrous metal matrix metal composites, NanoSteel has the potential to generate cost-efficient wear parts to serve the tooling, mining, energy, and transportation industries in applications such as pumps, bearings, and cutting tools.

“Additive manufacturing would allow you to produce any part, anytime, anywhere, at the time you really need it,” said Lemke. “NanoSteel’s materials are unique because we have a very different chemical composition than most steels do.”

Additive manufacturing of hard materials is difficult since the materials tend to crack once treated with the laser, Lemke said, but the microstructure of the new NanoSteel material avoids this problem. The company is seeking to team with selective lead customers in additive to bring new products to market. “In particular, we want to build more complex parts, impellers or other wear parts, as well as broaden the variety of materials that we can additive manufacture,” Lemke said.

NanoSteel is currently extending the material development into more complex geometries and broadening its property sets to fully validate the market potential for 3D-printed steel components. For more information on NanoSteel’s engineered powders for additive manufacturing, visit http://preview.tinyurl.com/AMpowders. ME


Revisiting Top Tech Papers

Last year Tech Front began to include highlights and topical selections from the SME Technical Paper collection. This continually updated online resource of more than 17,000 papers and presentations communicates the inspirations, insights and innovations of thousands of practitioners and researchers from all walks of manufacturing life.

As mentioned in the July 2013 Tech Front column, lean tops the list of most-accessed papers over the last five years, but revisiting the data reveals the rise of interest in 3D printing, rapid prototyping and additive manufacturing when the year-by-year list of downloaded titles is viewed.


A New Technology Emerges

“Rapid,” as in prototyping and tooling, shows up in paper titles beginning in the early 1990s. From then on, the number of papers and terms matches the advance of the rapid prototyping (RP) and additive manufacturing (AM) industry, as does the level of paper downloads.

In SME Technical Paper TP01PUB77, Philip M. Dickens of DeMontfort University (Leicester, UK) presented examples of using RP processes for manufacturing final parts in plastic and metal that “sparked a change in attitude … as RP machine manufacturers, material suppliers, and customers become convinced that these technologies are a viable option for manufacturing.” The author additionally noted that “probably the most important factor for the future will be the need to prepare manufacturing organizations for this new way of working.”

Several process chains based on the implementation of 3D printing as a rapid pattern making or rapid prototyping method were presented and discussed by D.M. Dimitrov and N. de Beer of the University of Stellenbosch (Stellenbosch, South Africa) in TP02PUB121. Their conclusions pointed to the need for more systematic research to control dimensional and form accuracy, along with development and availability of new materials that are more user-friendly, consistent and cost-effective.

In a paper presented at SME’s 1st Manufacturing Technology Summit in 2004, Ismail Fidan (Tennessee Tech University; Cookeville) assessed new product manufacturing using conventional CNC machines compared with advanced RP technology. The benchmarking results made it “clear that 3D printing is getting close to conventional CNC machining with a certain tolerance.… Although the 3D printing systems have a small build volume, their production time is the lowest available in the current RP market. …the short production time and colored processing features make the 3D printing one of the best RP options for many R&D centers, educational institutions, and companies.”  


Breakthroughs and Industry Trends

Rapid prototyping has been a revolutionary breakthrough in the medical field. Fabrication of custom titanium mesh cranioplasty plates for large skull defects using RP models was described in TP08PUB117, a paper presented at RAPID 2008 by J. Parthasarathy and J.K. Parthiban of the University of Oklahoma (Norman). The effect of the use of RP technology was a decrease in the number of surgical team members and surgical time, less anesthetic needed and shorter hospital stays despite the cost of fabrication of the model and implant.

Two papers from RAPID 2009 reveal the development of RP technology, processes and materials. TP09PUB17 describes the competitive advantages of selective laser melting (SLM)—geometrical freedom, shortened design to product time, mass customization and material flexibility—that helped shift process applications from rapid prototyping to rapid manufacturing. The authors, from the Catholic University of Leuven (Belgium), investigated improvements to SLM productivity and the influences of processing parameters on parts’ relative density and surface quality.

A hybrid manufacturing process produces precision 100% dense metal parts.

Frank Liou (Missouri University of Science and Technology; Rolla) and Mary Kinsella (Air Force Research Laboratory; Wright-Patterson AFB, OH) summarized current research and development of a hybrid manufacturing process to produce 100% dense metal parts with prescribed precision. The hybrid process was shown to be “potentially a very competitive process for fabrication and repair of fully dense metallic parts with precision requirements and will certainly impact the rapid manufacturing industry in the future.” The paper, TP09PUB18, received the 2009 Dick Aubin Distinguished Paper award from the Rapid Technologies & Additive Manufacturing (RTAM) technical community of SME.

A trends update from RTAM/SME (TP13PUB63) included several key observations for the future: continued industry consolidation, expanding technology capabilities, exponential numbers of new companies, niche business models, substantial application discovery and market displacements.


Rapidly, A Few More

Some other papers worth noting from the additive manufacturing library include: rapid manufacturing with electron beam melting (“…A Manufacturing Revolution?” TP03PUB397); rapid manufacture of EDM electrodes using selective laser sintering (TP00PUB135); RP of high density circuitry (TP04PUB221), wind tunnel models (TP04PUB87), and nonuniform shapes (TP03PUB59); and advancements in rapid solidification process tooling (TP04PUB338). Also, the past, present and future of rapid manufacturing in medicine (TP11PUB16); RP composite tooling (TP11PUB5); RP tooling considerations for RTM (TP97PUB16); rapid tool fabrication by powder metal forging (TP97PUB95); and RP using machining (TP99PUB53).

A final thought comes from TP91PUB444, “Rapid Product Development—A Competitive Advantage for the ’90s.” While mentioning prototyping (photopolymerization, selective laser sintering, fused deposition modeling and laminated object manufacturing) along with key technologies of CAD/CAM/CAE, advanced manufacturing processes and sourcing and partnering, rapid isn’t the paper’s focus. Yet the conclusions aptly describe the impact 3D/rapid/additive is having on advanced manufacturing.

The authors, from General Electric and speaking at SME’s AUTOFACT ’91, predicted “the rapid innovators who adopt new technological and organizational approaches to product development will be the leaders in profitability, growth, and technological innovation. It will be these innovators who will secure the competitive advantage.” ME


TechFront is edited by Senior Editors Patrick Waurzyniak, pwaurzyniak@sme.org and Ellen Kehoe, ekehoe@sme.org.

 

This article was first published in the November 2014 edition of Manufacturing Engineering magazine. Click here for PDF.


Published Date : 11/1/2014

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