PowderMet          AMPM          Special Interest          Carbide Forum

057 - Process and Property Trends for Powder Metallurgy HIP A508 Grade 4N
Colin Ridgeway, Naval Nuclear Laboratory

Powder metallurgy HIP (PM-HIP) is considered a key technology for component fabrication. By offering near-net shape forming, long lead-time components can be delivered quicker and more efficiently, ultimately supporting on-time construction of nuclear components and structures. To this end, the low alloy steel (A508 Grade 4N) was examined in the consolidated PM-HIP condition to assess the mechanical behavior as well as similarity to their wrought/forged counterparts. In this study, various aspects of the PM-HIP process were explored from the powder production to the consolidated material and eventual heat treatment to develop a greater understanding of optimized mechanical properties of PM-HIP material. Trends in processing conditions and various heat treatments were correlated to the performance of each material and related to the wrought counterpart. 

009 - As-HIP Near-Net Shapes as an Alternative to Forgings and Castings
Eric Bono, PMT, Amaero Advanced Material & Manufacturing, Inc.

Extremely large and complex as-HIP near-net shapes (NNS) are becoming a more attractive option compared to hogging material out of large forgings and plates or trying to acquire large castings. HIP technology has demonstrated the ability to make large components with better mechanical properties and pose less challenges with non-destructive inspection than conventionally fabricated materials. The costs and long lead times associated with forged or cast components can put a program’s budget and schedule in jeopardy. This talk will explore the technical work being done on HIP’ing large parts and provide a detailed business case comparing our process to conventionally forged and cast routes. 

102 - Initial Results on PM-HIP Nickel Base Alloys
Rachel Turfitt, Naval Nuclear Laboratory

A testing program for the characterization of powder metallurgy – hot isostatic pressed (PM-HIP) nickel base alloys 600, 690, and 625 for the potential use as direct replacements to wrought materials is underway. Given the widespread acceptance of these materials in their wrought forged and cast forms, the testing approach aimed to show that PM-HIP materials resulted in properties comparable to those expected for wrought versions of these alloys. While minor differences compared to wrought materials have been identified (both better and worse performance depending on the alloy and property), all three alloys perform similarly to their wrought counterparts in a majority of tests. Current work is underway to better understand the structure-processing-property relationships to inform improvements to the processing methods that will result in properties more in-line with wrought material properties. This presentation will outline the scope of the approach which was undertaken, results on all three alloys highlighting similarities and differences with wrought properties, and current development efforts to improve the properties with respect to wrought materials. 

045 - Machining of Low Alloyed Chromium PM Steels
Bo Hu, North American Höganäs Co.

Chromium as a sustainable low-cost alloying element can offer potentials for powder metallurgy (PM) materials to achieve desired sintered properties. The low-alloyed chromium PM steels exhibit good sinter-hardening responses and stable dimensional tolerance, providing capability in replacing conventional copper steels and low-alloyed steels. However, the sinter-hardened chromium alloyed steels face challenges in machining compared to other sinter-hardened and heat-treated PM steels. Understanding the machining responses of PM steels alloyed with different levels of chromium and exploring solutions for improved machining is of interest. This paper examined the machinability of conventional sintered and sinter-hardened low alloyed chromium PM steels made with three types of commercial pre-alloyed chromium steel powders.

016 - Challenges and Opportunities in Production of PM HIP Components
James Shipley, Quintus Technologies

Hot isostatic pressing (HIP) has been used in the production of powder metallurgy components (PM HIP) for the last 50 years. Demands for near net shape components have been focused on corrosion resistant environments predominantly in the energy sector, with a heavy focus on the offshore industry and nuclear power generation segment.
The development of small modular reactor concepts and advanced modular reactors have identified challenges in the supply chain with respect to flexible production of pressure vessel components, particularly in the limitations of forging capabilities. The Atlas project in the USA, pioneered by EPRI (Electric Power Research Institute), has been investigating the opportunity to develop large scale production of PM HIP components as an alternative to traditional production processes.
In this paper, PM HIP production will be presented, along with recent developments in equipment design to product large near-net shape components. 

015 - Sinter-Steam Furnace Design for Inline Sintering and Steam Treatment of Iron Parts 
Ravindra Kumar Malhotra, Malhotra Engineers

Steam treatment or steam oxidation is an important secondary process for powder metallurgy iron parts. Steam treatment process has an important segment which is commonly known as degreasing or oil removal. There are many types of iron parts which need oiling only for rust prevention before the parts are sent for the steam treatment process. Parts which can be steam treated straight after sintering can have a combined sinter-to-steam process in the same furnace. This combination has been previously tried out using wet nitrogen in the cooling section. Sinter-steam process using boiler steam or a boilerless steam looks feasible in near future due to recent developments. It is worth exploring the design feasibility and associated challenges to develop this new combined process of sinter–steam. A new family of PM parts may emerge from this integrated sintering and steam treatment process which will eliminate shop floor inventory awaiting steam treatment which otherwise needs unnecessary protection from rust formation. Sinter-to-finish parts process perfection will be a prerequisite of sinter-steam process envisaged here. This new process will start deeper understanding of sintering as well as steam treatment processes using same belt speed in this version of sinter–steam furnace.

006 - Hot Disk Thermal Characterization of Copper Powder and AM Copper Parts
Artem Trofimov, Orton Ceramic Foundation

Thermal characterization (thermal conductivity; specific heat capacity, etc.) of metal and ceramic additively manufactured (AM) parts is critical for modeling and simulations, optimization of the processing parameters, and can be used for quality evaluation of components at different steps of manufacturing. Such characterization is especially vital for materials, whose applications are directly related to their thermal properties; a great example is pure copper with an excellent combination of both thermal and electrical conductivity.
In this work, hot disk transient plane source (TPS) technique is demonstrated as a suitable and convenient tool for thermal characterization of raw copper powder as well as green and sintered AM copper products. The investigation demonstrates how the hot disk method allows evaluation of most pivotal thermal properties, thermal conductivity and heat capacity, and the applicability of the technique to both powders and solid samples. Flexibility of the sample size requirements (from a few millimeters and larger) is also discussed.

038 - Relating Powder Cohesiveness to its Spreadability in Powder Bed-Base AM
Aurélien Neveu, Granutools

The powder spreadability is a critical parameter for any powder bed-based additive manufacturing process. Indeed, the quality of the deposited layer is directly influencing the quality of the final part. Producing smooth and homogeneous layers is thus a strong requirement for these processes. However, powders made of fine particles usually exhibit cohesive behavior leading to a lack of flowability and subsequently poor spreadability. Being able to predict the powder spreadability with a simple metric without having to produce a large batch and fill the machine should thus provide an interesting tool for process improvement.
In a previous study, the spreadability of metal powders has been shown to be strongly linked to their rheological properties measured in a rotating drum. This first investigation highlighted the importance of powder rheology on spreadability, especially when varying the recoater translational speed. In the present work, the previous study has been extended to a wider range of materials: Ti-Al6-V4, Ti-Nb, Fe-Co, Ni, Ni-Ti, Al-Si12, 316L. We show that the correlation of the Cohesive Index and the actual spreadability in the LBPF printer still hold for these materials. Moreover, powder layers have been spread at various recoater speeds in the printer and related to the rheological behavior of the powders in the rotating drum. These results demonstrate the usefulness of the Cohesive Index as a metric of choice to predict powder spreadability.

051 - Characterization of Oxygen-Related Defects in Electron Beam Melted Tungsten
Colin Fletcher, North Carolina State University

Oxygen's presence in the additive manufacturing (AM) build environment plays a critical role due to its reactivity with tungsten. The unintended accumulation of oxygen during raw material processing and oxidation of powder act as a source for the formation of grain boundary oxides. In this study, we conducted an investigation into the effects of oxygen in electron beam melted (EBM) tungsten samples. Samples which exhibited in-process cracking were characterized. Characterization of these samples was performed using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) to gain insights into the nature and morphology of pores/voids and grain boundary oxides.

116 - Implementation and Impact of Mechanically Derived Powder in Cold Spray Additive Manufacturing (CSAM)
John Barnes, The Barnes Global Advisors

The importance of feedstock is well known in the additive manufacturing (AM) community. It drives process-structure-property-performance relationships through a combination of morphological, mechanical and chemical/metallurgical behavior, and thus variation in feedstock yields variation in performance. Moreover, feedstock also represents one of the largest costs in AM and source of emissions when utilizing energy intensive atomization techniques. Recently, a solid-state method of powder manufacturing has garnered attention due to low energy input and a higher efficiency in producing consistent targeted yields or ‘cuts’, and the associated reduction in wastage, and therefore emissions and cost. A potential concern has been that this process yields lower sphericity powders; the suitability of which is unknown for AM. In this work, mechanically derived alloy powders were explored for usage in a cold spray additive manufacturing (CSAM) system. As cold spray is also a solid-state process and can produce components at a rate of L/hr, this represents a potential means of rapidly, efficiently and economically producing AM components. Further, it was envisioned that the non-spherical nature of the feedstock could potentially benefit the cold spray process. This study compares atomized and solid state feedstock in terms of processability via CSAM, and the resulting build morphology and mechanical performance. 

028- Material Selection for Lithography-Based Metal Manufacturing of Components with Intricate Features and High Surface Quality
Gyorgy Harakaly, Incus GmbH

Additive manufacturing (AM) technologies offer components with a remarkable degree of shape complexity and design flexibility. Well-established metal AM processes encounter challenges in delivering these advantages for small part sizes. This issue becomes critical when producing components with intricate geometric features, crucial for industries like medicine, electronics, and aerospace. Meeting the demanding surface roughness requirements (Ra < 1 µm) for such applications proves elusive with existing commercial AM methods, necessitating additional, costly post-processing steps. The lithography-based metal manufacturing (LMM) process, a sinter-based AM technology, provides a manufacturing solution for the mentioned applications.
The feedstock for LMM consists of a blend of metal powder and photopolymerizable resin, which solidifies using light to construct a three-dimensional structure layer by layer. The resulting components undergo debinding and sintering processes to yield the final product.
The LMM process achieves an Ra of 1.5-3 µm without the need for post-processing, a factor contingent on the distribution of powder sizes and shapes used, typically with a d90 <25 µm. To further reduce potential post-machining costs in applications where superior surface quality is imperative, evaluating metal powders with various size ranges is desirable.
In this context, we present here an exploration of the effects of different powders on the processing and the quality of parts produced using the LMM process, employing 316L and 17-4 steel alloys.

011 - Additive Screen Printing: Industrialized Additive Manufacturing Technology for Powdered Metallurgy, Ceramic Part Production
Eric Bert, Exentis North America, Inc.

Additive screen printing is a new approach to sinter-based additive manufacturing for industrial production. A new unique technology platform using conventional screen printing techniques combined with high-speed precision optics and industrial handling automation is introduced that enables mass production of industrial parts with ultra-fine structures using a wide range of metals, ceramics, and other materials. This presentation will outline how the technology works, its capabilities compared to conventional sinter-based PM, MIM/CIM, and other additive techniques, and resulting material properties as well as discuss several successful applications that are in volume production. 

540 - From Powder to Profit: Sales Growth in the PM Industry
Anthony Nicks, Transformative Sales Systems

In the highly specialized field of powdered metallurgy (PM), businesses face unique challenges in scaling their sales and enhancing profitability. "From Powder to Profit: Sales Growth in the PM Industry" is a comprehensive presentation designed to address these challenges head-on. This talk is tailored for business owners and operators in the PM sector, offering innovative and actionable strategies to drive revenue growth.
A significant focus is placed on streamlining the sales process to enhance efficiency and reduce sales cycle times. This includes adopting modern sales tools and CRM systems, refining sales pitches to resonate with the specific needs of PM clients. Practical tips for effective lead generation and conversion in the PM industry are also discussed, ensuring attendees can immediately implement these tactics in their operations.
Attendees will leave with a clear understanding of the dynamics of sales growth in the PM industry and a toolkit of strategies to apply to their businesses. The session includes case studies, interactive discussions, and a Q&A segment, encouraging active participation and exchange of ideas among industry peers.
"From Powder to Profit" is more than just a presentation; it's a roadmap for PM businesses to navigate the complexities of the market and achieve sustainable growth in revenue and profitability.

410 - Consolidation of RTP Powder

Several common methods for shaping and densification of cemented carbide powders are used to produce green preforms that can be sintered.  The ideal method depends on the overall size, geometry, and yearly production volume.  The most common methods are uniaxial die pressing, extrusion, cold isostatic pressing, green machining, and injection molding.  Powder characteristics are customized for each method, including binder types and amounts, packing densities, and flow properties.  The equipment, tooling, and process parameters for each method are optimized to produce an ideal green part.

411 - Sintering Methods and Processes for Cemented Carbides

Sintering of cemented carbides is typically achieved through liquid phase sintering to achieve a nearly pore free microstructure.  In this process, the grain size, carbon content, and porosity are controlled by the debinding, deoxidation, presintering, and sintering temperature, as well as the furnace atmosphere and pressure.  Several common sintering methods exist, each with specialized furnaces.  Some methods apply pressure, either by mechanical means or high pressure gas, to assist in the densification.  The specifics of the powdered carbide grade, including the binder metal chemistry and amount, carbide type and grain size, as well as the green properties of the compact such as binder type and amount are all important in optimizing the debinding and sintering parameters to achieve the sintered properties that the grade requires.

412 - Recycling of Hardmaterials
Amy Herron, Tungco

Tungsten is identified as US critical mineral by the Department of Energy (DOE). As per the US Geological Survey (USGS in 2022, tungsten was again identified as one of the 50 minerals deemed critical. Tungsten primary materials are dependent on imports as there are no current mining operations within the USA.  Therefore, tungsten scrap, secondary raw materials, have become a significant raw material feed as an input into the chemical (APT) as well as the zinc-reclaim process. Current recycling practices of tungsten carbide (WC)-based scraps have historically been accepted as economically beneficial and promotes tungsten closed-loop recycling.  However, growing pressure to increase utilization of these scrap units have begun to apply pressure on the availability and sustainability in this space.  This presentation and discussion will include facts on the current recycling rates, future demand projections, alignment with projected supply, as well as sustainability and potential challenges in material acquisition.