Joseph Capus, MPR consulting editor, reports from the European powder metal conference and exhibition, this year taking place entirely online.

For a second time the annual European powder metallurgy conference was affected by the pandemic and as a result, the Euro PM2021 Congress and Exhibition was held online as a five-day virtual event on 18-22 October 2021. Speakers and audience joined in from around the world. EPMA executive director Lionel Aboussouan introduced the Opening Plenary Session by welcoming the participants and thanking the sponsors, headed by Rio Tinto/QMP, and the organizers. He went on to review EPMA activities in 2021 such as the technology sector seminars, webinars, publications, etc and some of the plans for 2022.

EPMA President Ralf Carlström, in his overview of the status and trends in the European PM industry, described 2020 as “a year of adaptation and hope”. As elsewhere, production and consumption suffered heavily as a result of the pandemic. Ferrous powder production in the EU fell by 13.1%, while non-ferrous powder production was down 20.1% for a combined total of 201,000 t, of which 191,000t was for pressed and sintered ferrous parts. In terms of value, the EU parts production in 2020 totaled €10.54bn, down 9.4% from 2019. Of this, ferrous and non-ferrous pressed and sintered parts represented 27% (down 12%), while metal injection molding (MIM) parts represented 4% (down 8.7% in value and representing the first decline for MIM since 1991). On the automotive applications side, pressed and sintered parts for this sector fell 19.3% for a total of 158,000 t. The production of passenger cars in the EU fell 22.3% in 2020 to 10.8 million. In the first half of 2021 EU passenger car production bounced back 25.2% to 5.4 million units. 

Turning to the current outlook for the powder metal (PM) industry in the EU, Carlström noted that the electrification of cars will be a game-changer for industry and for PM. The trend is already gathering pace as shown by figures quote by Carlström comparing the 2020 breakdown for the types of passenger car propulsion with figures for 2019. Hybrid electric vehicles doubled from 5.9% to 11.9%, while pure electrics grew from 3% to 10.5%. He quoted a projection that forecasted 48% of global new car sales will be electric by 2030, Battery costs were decreasing rapidly and expected to reach cost-parity with ICEs by 2025, when battery production capacity will match demand. On the hydrogen economy outlook, Carlström added that hydrogen electrolyser capacity will rise steeply after 2022 to more than ten times the current capacity.

He went on to note the increasing demand for PM in the aerospace market, with parts produced by metal additive manufacturing (AM), MIM, and hot isostatic pressing (HIP), and that the value of this market was projected to grow more than five-fold by 2030.

EPMA awards

Carlström announced two EPMA Fellowship Awards for 2021: Professor Didier Bouvard, Université Grenoble Alpes, France, and Professor Lars Nyborg, Chalmers University of Technology, Sweden. He also announced two new Awards for Distinguished Service, to Martin Blömacher, BASF SE, Germany, and Dr Ing Harald Neubert, MIBA AG. Further awards were announced by Dr Aboussouan, for the EPMA Thesis Competition (Dr Felicity Freeman, University of Sheffield, UK, and Ing. Gerald Wilhelm, Aalen University, Germany). Six new Keynote Paper Awards sponsored by the publisher of Powder Metallurgy were also announced. These papers were presented during the virtual congress and will be published in forthcoming issues of the journal. Finally, Dr Aboussouan introduced Adeline Riou, global sales manager, Aubert & Duval, France. who made a brief presentation about next year’s World PM2022 Congress and Exhibition (of which she is co-chair with Professor Bouvard), to be held in Lyon, France, 9-13 October 2022. 

Plenary keynote speaker

This year’s keynote speaker was Dr Lars Röntzsch, head of the hydrogen technology department at Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Dresden, Germany. He chose a highly topical theme for his talk: “Opportunities for the PM industry in the hydrogen economy”. He began by noting the ongoing discussions about the importance of hydrogen as an energy carrier as well as a fuel. He believed that “green hydrogen” will be a key element in the transition from fossil fuels to renewable energy and fuels. Why hydrogen? The answer is because it can be produced and used as a fuel without creating undesirable emissions. It has a very high gravimetric energy density when liquid (33.3Kwh/kg), nearly three times higher than petrol (but low as a gas). It is as abundant as water, but it’s not free!

Röntzsch went on to explain some of the aspects where opportunities are emerging for the use of PM technology in a hydrogen economy. For example, sintered porous electrodes are used in water electrolysis – an important way to make hydrogen using renewable energy. Building of electrolysis units will create a huge demand by 2030 in Germany, for example. Also, reversible metal hydrides are being used as hydrogen storage materials. A variety of compacted metal hydrides and metal hydride composites, processed using PM techniques, can provide an alternative hydrogen storage approach at low pressure and with high volumetric capacity. Other applications for PM include gas purification and in fuel cells. He concluded by mentioning some of the areas of expertise in this technology that Fraunhofer IFAM was able to provide.

Euro PM virtual exhibition

The real innovation for 2021 was the first ever Virtual Euro PM Exhibition which contained thirty booths representing powder producers and supplier companies from all sectors of the supply chain. Attendees were able to click through various levels to see the latest company offerings and have live chats.

Technical sessions

About 150 presentations were made in 52 sessions, with a virtual poster display of about 20 items. There were a number of special interest seminars on selected topics. Session topics included every aspect of powder metallurgy materials and processes, as well as all forms of metal AM. Well over half of the technical sessions were either devoted to AM topics or included AM-related papers. Application areas included automotive, aerospace, biomedical, and energy. Sustainability and CO2 reduction were recurring themes in the presentations. Leading European and global industry producers and suppliers led some of these discussions. Powder producers such as Höganäs AB, furnace manufacturers Cremer, and gas supplier Air Liquide outlined their plans, programs and target dates for becoming carbon or climate-neutral. Air Liquide, for example, it was said, plans to reduce CO2 emissions by 30% (from 2017) in 2025 and to achieve carbon neutrality by 2050. Höganäs, according to Dr Hilmar Vidarsson, plans to be climate-neutral by 2045. For PM sintering furnaces, on the other hand, the carbon footprint from the protective atmosphere was highly dependant on the country of location because of the strong impact of widely varying national grid emission factors. Practical details for optimizing energy consumption (for press and sinter parts) were discussed by Pietro Albonetti of press manufacturer SACMI and Narayana Kaushi Karthik of Cremer Thermal Processes.

All of the now familiar metal additive manufacturing and 3D printing processes are under extensive development with a wide range of promising materials. One repetitive concern was the achievement of satisfactory densification and reliable mechanical properties. This was seen as a motivation for post-AM densification by hot isostatic pressing. This process, combined with heat treatment of suitable alloys was also discussed, and was seen as a way of increasing the low productivity of AM, for example, using high-speed powder bed fushion laser beam (PBF-LB) followed by HIP. Anton du Plessis, of Stellenbosch University, South Africa, showed how manufacturing of PBF-LB parts could be speeded up by placing the powder in a shaped can and HIPing after AM processing. Fully-dense Ti64 alloy parts could be produced ten times faster by this method. HIPing on a much larger scale was discussed by David Gandy, Electric Power Research Institute (EPRI), USA. He described a plan to build a massive (3.55m diameter) new HIP unit in conjunction with Stack Metallurgical Co and US government agencies, The purpose was to be able to replace heavy forgings in nickel-chromium, titanium alloys and stainless steel with HIPed powder components, for example, for use in small nuclear power reactors. The proposed ATLAS PM-HIP unit could also be used to densify large castings. The project is currently at the stage of raising finance to enable the scheme to go forward. Main applications for the unit would be in the electric power industry, as well as aircraft manufacture, and aerospace sectors.

Another new development for an EPMA conference technical program was an “Industry Corner”. Two complete sessions were given over to companies with new processes, products, or services to offer. Incus (Vienna, Austria) introduced its lithography-based metal manufacturing (LMM) process. This is an AM process employing a metal/polymer combination, in which polymerization by light is followed by heating to remove the polymer and sintering of the remaining “green” metal part. The process uses metal powders similar to MIM powder, and has applications in electronics, medical and dental devices, etc. LMM is claimed to provide the highest resolution among AM processes.

Another company, Granutools, based in Belgium, offers a variety of powder testing equipment and procedures for metal AM process characterization. ELTRA (a part of VERDER Scientific) located in Haan, Germany, showed a range of instruments for elemental analysis in AM parts. Then Kenan Boz, Technical Manager of EPMA, spoke about the Sector Skills Strategy for AM (SAM) Project and gave an update on the international AM qualification system being built to establish skills development for AM operators and designers. The aim is to address the skills shortage in Europe and the project is being funded with support from the European Commission.

Finally, getting back to conventional PM, speakers from Höganäs AB and GKN Sinter Metals Engineering GmbH addressed the subject of developing static and dynamic mechanical properties in sintered and heat-treated high-strength low-alloy PM steels. Ruben Schneider (Höganäs) spoke about the influence of composition and cooling rate from sintering on the static mechanical properties of Astaloy CrM (3% Cr + 0.5%Mo) PM steel containing zero to 3% admixed nickel. The objective of the work was to achieve improved elongation values together with sufficient hardness, tensile and fatigue strength, utilizing more economical belt furnace conditions (1120⁰C) rather than sintering in a higher-temperature walking-beam furnace. He showed the benefits of nickel additions between 0.5 and 1.5% and concluded that the addition of nickel could significantly improve the mechanical properties of Astaloy CrM when sintered at 1120⁰C and sinter hardened.

Also at Höganäs, Christophe Szabo reported on a very complex series of tests to bench-mark the tooth-bending fatigue strength of a 350 gram spur gear. The test program comprised 18 different sets of materials and treatments. These included Astaloy CrA and Astaloy 85Mo steels, as well as treatment by induction hardening, carburizing, plasma nitriding and carbo-nitriding. The best results were obtained with gas-carburizing and quenching of Astaloy CrA. Plasma nitriding gave the lowest results, showing little benefit for this treatment while plasma carbo-nitriding gave slightly better results.

Markus Schneider and colleagues at GKN studied the static and high-cycle (fatigue) mechanical properties of Astaloy CrA (containing 1.8% chromium) when alloyed with 1% copper and 0.2% carbon, after sintering and case-carburizing, followed by quenching in high-pressure helium. They measured the static and fatigue properties for samples compacted at densities of 7.0, 7.1, and 7.2g/cm³. They found lower than expected static mechanical properties, but the fatigue notch factor was very low.

In a key-note paper on the same topic area, Phillipp Scholzen and Ali Rajaei of RWTH Aachen University, Germany, discussed the influence of heat treatment and surface densification on the load capacity of sintered gears. They noted the significant resource efficiency in terms of materials and energy of using PM gears versus conventional steel gears. They studied the case hardening and tempering of PM gears followed by surface densification and developed a simulation model. They compared a PM steel containing 0.85% Mo and 0.25% C with a wrought 16MnCr5 steel. They found that increasing the densification depth and the case-hardening depth each improved tooth root and tooth flank load capacity. Also, sub-surface density-dependent crack growth could be minimized through increasing case hardness depth.

In the closing session, the Peter Brewin Poster Award was announced; the winner was Mouchard Adrien, University of Limerick, Ireland, for his poster entitled “Effect of gas flow rates on powder flow characteristics and efficiency from co-axial nozzles”. Finally, Professor Didier Bouvard (Université Grenoble Alpes, France), co-chair of next year’s World PM2022 Congress and Exhibition, to be held in Lyon, gave a brief overview of the architectural and cultural attractions of this 2000-year-old UNESCO World Heritage City, which is acclaimed as the gastronomical capital of France.