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Laser Powder Bed Fusion (L-PBF) is the main technology for additive manufacturing of metallic components and is primarily used for rapid prototyping and tooling in cases with very complex geometry or lightweight design and small quantities. There are manifold influencing parameters, which need to be optimized in order to build components with suitable properties. The paper deals with three distinct application fields, like the development of new tool steel grades for injection molds, light weight design using aluminum alloys with optimized post-weld heat treatment as well as production of copper alloys without porosity. The most sensitive process parameters are displayed and the multilayered components are characterized using light and high-resolution microscopy as well as mechanical testing.

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A numerical procedure for the simulation of solidification and micro-segregation is presented. The iterative solution algorithm is based on the classical Scheil – Gulliver model; however, the new algorithm allows taking into account partial redistribution of fast diffusing elements and solid – solid phase transformations, such as the peritectic reaction in low-carbon steels. It is shown that, especially in interstitial/substitutional alloys such as steels, simulations performed with the new algorithm give considerably different predictions as compared to simulations carried out with the classical Scheil – Gulliver procedure. The new procedure is described in detail and the results are validated on experimental data, i. e. micro-segregation measurements, the determination of the brittle temperature range for hot-cracking and experimental data on the specific heat capacity during solidification.

Recent developments of direct heat-treated steels for high strength forgings have led to some new steel grades with excellent service properties. Quenched and tempered steels are nowadays more and more replaced by precipitation hardened ferritic-pearlitic steels and by bainitic steels. Based on the experience on upper, lower and carbide-free bainite, a critical assessment is performed concerning the most important influencing parameters and processing routes. Steel designs and cooling concepts are discussed regarding their optimal chemical composition, achievement of a homogeneous microstructure and a low sensitivity to processing parameters. Some controversial aspects are illustrated and further need for research work is highlighted.