Development of a high productivity 316L stainless steel for direct metal laser sintering
Niemelä, Ville Petteri (2018)
2018
Materiaalitekniikka
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2018-02-07
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201801231144
https://urn.fi/URN:NBN:fi:tty-201801231144
Tiivistelmä
Additive manufacturing (AM) has seen a substantial growth over the last 20 years. This is because AM offers several benefits over other manufacturing methods. These benefits include unrivalled freedom of design, short lead times, minimal or no assembly required, minimal waste of material, and energy savings in several stages. [1] Additive manufacturing of metals, however, also has its drawbacks, such as low efficiency, high cost [2], relatively long processing time, and less developed online quality assurance. This thesis will focus on the two latter drawbacks.
In this thesis, the focus will be on a particular powder bed fusion process called direct metal laser sintering (DMLS) which is a trademark of Electro Optical Systems GmbH. Today the word sintering is misleading; the metal powder is completely melted in the laser scanning process. The word sintering is a historical remain from the time when the powder was actually sintered. [3]
Austenitic stainless steel (SS) 316L (L stands for low carbon) is one of the most common stainless steel types. The 316L is an austenitic, low carbon variant of the stainless steel 316. Lower carbon content yields better welding properties, while still having good corrosion resistance and mechanical properties. [4]
Motivation for this thesis is the aim to increase the productivity of the DMLS process by altering process parameters, and by using a less expensive water atomized 316L powder. Water atomizing is a more cost efficient method than the normally used gas atomization [5]. Different atomization processes produce different powder morphologies, which will affect the quality of the part.
In this thesis, the focus will be on a particular powder bed fusion process called direct metal laser sintering (DMLS) which is a trademark of Electro Optical Systems GmbH. Today the word sintering is misleading; the metal powder is completely melted in the laser scanning process. The word sintering is a historical remain from the time when the powder was actually sintered. [3]
Austenitic stainless steel (SS) 316L (L stands for low carbon) is one of the most common stainless steel types. The 316L is an austenitic, low carbon variant of the stainless steel 316. Lower carbon content yields better welding properties, while still having good corrosion resistance and mechanical properties. [4]
Motivation for this thesis is the aim to increase the productivity of the DMLS process by altering process parameters, and by using a less expensive water atomized 316L powder. Water atomizing is a more cost efficient method than the normally used gas atomization [5]. Different atomization processes produce different powder morphologies, which will affect the quality of the part.