Additive manufacturing processes, and in particular laser powder bed fusion (L-PBF), are used in a wide variety of industrial sectors. These include aerospace, medical technology, the automotive industry and mechanical engineering. Due to the layered product structure, components with a very high level of complexity can be produced.
Additive manufacturing with powder, known as selective laser melting (SLM), is a process in which a powder bed of, for example, metal or plastic powder is built up layer by layer. A laser beam melts the powder at the desired points to create a layer of the object. A new layer of powder is then applied and the process is repeated until the entire object has been created.
Additive manufacturing with wire, on the other hand, also known as wire arc additive manufacturing (WAAM), is based on the melting of a metal or alloy wire. The wire is melted by an electric arc or a laser beam and applied to the desired areas in order to build up the object layer by layer.
Both approaches have their advantages. Additive manufacturing with powder enables high precision and attention to detail, as the powder is applied in fine layers. It is also suitable for complex geometries and can process a variety of materials. Additive manufacturing with wire, on the other hand, offers a high build speed and can produce large-format objects. The choice of additive process depends on the specific requirements of the application.
The Swiss steel Group offers a wide range of gas atomized metal powders based on Fe, Ni and Co. The basis for the production process is a high-quality metal powder, the manufacture of which involves complex process steps. To produce the powder, the raw and input materials are first melted in an induction furnace and then fed into a gas atomization system. In a closed container, the melt jet is atomized under high pressure using an inert gas (nitrogen). The resulting particles form a spherical shape during the cooling process. This is the only way to ensure suitable flow behavior, which is crucial for subsequent further processing. Finally, the spherical shape improves the dosing properties of the powder.
This part of the process takes place entirely under inert gas, which cools the powder without harmful surface oxidation. The metal powder is then sieved and air-sifted. This means that the powder is prepared in this way for use in additive manufacturing, for example. The particles that are too fine and too coarse are removed so that the typical particle distribution for 3D printing of 10 - 63 µm is produced. With the metal powder in the required particle size distribution, the basis for the actual 3D printing process is created. At the end of production, the powder is homogenized and packaged and labelled according to customer specifications.
In the powder bed process, as already mentioned, components are built up layer by layer. This is why these processes are referred to as "additive" processes. A laser serves as the energy source in the L-PBF process, which welds the metal powders together at micrometer level. This creates a three-dimensional component layer by layer, which can have a very complex structure.
This complexity, or rather the possibility, is one of the major advantages of these new manufacturing processes. However, the new possibilities also bring with them new requirements and challenges. On the one hand, there is a need for new and adapted materials so that the maximum potential can be extracted from this technology. On the other hand, the new possibilities must also be implemented in industrial practice.
Iron-based metal powder
Iron-based metal powders for 3D printing can be divided into austenitic, age-hardenable and martensitic grades. The austenitic grade Printdur 4404 has high corrosion resistance and good oxidation resistance. The grades Printdur 4545 and Printdur 4548 have the optimum combination of wear, corrosion and oxidation properties. The grades Printdur Powderfort, Printdur 2343 and Printdur 2344 are a good choice for increased wear resistance.
Nickel-based metal powder
Our nickel-based metal powder is ideal for applications that require high corrosion resistance. Printdur Ni625 has good resistance to mineral acids such as nitric, phosphoric, sulphuric or hydrochloric acid. It is also corrosion resistant to alkalis and organic acids. Furthermore, in the solution-annealed condition, the material has good resistance to hot gas corrosion and high creep rupture strength above 600°C.
Cobalt-based metal powder
The cobalt-based metal powder (Printdur CoCrF75) can be used in two different areas: High temperature applications and medical technology. Printdur CoCrF75 has excellent resistance to thermal shock and is resistant to oxidizing and reducing atmospheres up to approx. 1150 °C. Its properties also include very good biocompatibility and corrosion resistance.
Bainidur AM
Bainidur AM (= Additive Manufacturing) expands the portfolio of metal powders. There are currently only a few low- and medium-alloy steels available on the market that can be processed using additive manufacturing. Bainidur AM, on the other hand, meets this need as it enables fast and efficient printing of initial samples that also exhibit the subsequent component properties. Heat treatment and thermochemical surface treatments can be tested and optimized with the same material as in series production.
Even spare parts can be produced using additive manufacturing with properties comparable to the original. This is supported by its good conversion behavior in the bainite structure. This also makes the material easy to handle during printing.