Additive manufacturing (AM) of metals is stimulating the tool making industry. Moreover, besides the production of lost forms, AM processes are now being used to directly generate tools, molds or parts, leading to massive time savings. In the case of material development for AM, the challenge is to operate with carbon-containing iron-based materials distinguished by high strength and hardness, as well as high corrosion resistance and thermal conductivity. Often, those materials are susceptible to crack formation during processing. Using Electron Beam Powder Bed Fusion (PBF-EB), the challenge of crack formation can be overcome by using high process temperatures in the range 800–900 °C. In this paper, results on the processing of a cold-working tool steel (X65MoCrWV3-2) and a hot-working steel (X37CrMoV5-1) will be presented. These include the processing window, processing strategies to minimize the density of cracks and properties with respect to microstructure and hardness.
Due to the small variety of materials, the areas of application of additive manufacturing in the toolmaking industry are currently still limited. In order to overcome these material restrictions, AM material development for high carbon-containing iron-based materials, which are characterized by high strength, hardness, and wear resistance, must be intensified. However, these materials are often susceptible to crack formation or lack of fusion defects during processing. Therefore, these materials are preferentially suited for electron beam powder bed fusion (PBF-EB). In this paper, an Fe-Cr-V alloy with 10% vanadium is presented. Investigations were carried out on the PBF-EB system Arcam A2X. Specimens and demonstrators are characterized by a three-phase microstructure with an Fe-rich matrix and VC and M7C3 reinforcements. The resulting microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Furthermore, mechanical and physical properties were measured. A final field test was conducted to evaluate durability in use.
In the present state of the art, highly spherical alloy powders are employed as feedstock in powder bed fusion processes. These powders are characterized by high flowability and apparent density. Their elaborate fabrication process is reflected in high powder price, adding a significant fraction to the cost of additively manufactured parts. Thus, the use of non-spherical powders, such as water atomized material, can lower costs significantly. Here, the electron beam powder bed fusion (PBF-EB) of standard water atomized iron powder used for press-and-sinter is studied. Despite raking problems, using the coating mechanism in standard configuration samples with densities exceeding 99% were fabricated. In a further step, the addition of alloying elements by powder blending is explored. Important powder properties of feedstock blended from irregular and spherical powders are characterized. The PBF-EB processing of two alloys is presented. The first represents a low carbon steel. Samples were characterized by metallographic cross-section, energy dispersive X-ray (EDX) mapping, and mechanical testing. The second alloy system is a FeCrAl. After PBF-EB processing of the powder mixture, chemical homogeneity was achieved. Besides the low cost, this approach of using water atomized powder mixed with master alloy offers the advantage of high flexibility for potential application.
In diesem Beitrag wird ein innovatives Verfahren für die Verbesserung des Metallpulverspritzgusses (MIM, Metal Injection Molding) vorgestellt. Die Bauteile werden einem am Fraunhofer IFAM in Zusammenarbeit mit der MUT Advanced Heating GmbH weiterentwickelten elektrochemischen Reduktionsverfahren unterzogen. Infolgedessen konnten feinere Ausgangspulver mit erhöhtem Sauerstoffgehalt eingesetzt werden. Gleichzeitig war es der Firma Element 22 möglich, die Entwicklung des MIM-Feedstocks auf die Bauteilqualität und Verarbeitbarkeit zu optimieren, ohne einen möglichen Sauerstoffeintrag aus dem Prozess berücksichtigen zu müssen. Das Ergebnis sind Titanbauteile höchster Oberflächengüte innerhalb der geforderten Norm. The content of the paper is an innovative process for improving metal injection molding (MIM). The components are subjected to an electrochemical reduction process further developed at Fraunhofer IFAM together with MUT Advanced Heating GmbH, which has enabled finer starting powders with increased oxygen content to be used. At the same time, Element 22 was able to optimize the development of the MIM feedstock for component quality and processability without having to consider a possible oxygen input from the process. The result is titanium components of the highest surface quality within the required standard.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.