Effects of Heat Treatment on Microstructural Evolution in Additively-manufactured Parts of Various Heights from Maraging Steel

Parts made by 3D printing must be subjected to heat treatment to achieve the required mechanical properties. With the development of additive manufacturing in various areas of industry, more and more complex components are being printed, which, in addition to their complicated shape, also have different printing heights. Sometimes, builds of different heights are created on a single build platform. When there is height difference, the step region is characterized by a steep increase in hardness. It may lead to problems related to mechanical properties. MS1 tool steel was chosen as the material for this experiment. Using DMLS (Direct Metal Laser Sintering), a build with considerably greater height was created on the build platform together with other parts. Metallographic examination of the printed part was carried out and its hardness profiles were measured prior to as well as after heat treatment. The drop in hardness in the build of different height was up to 40 HV10. Solution annealing at 820 degrees C removed the transition produced by building a single part, both in terms of microstructure and mechanical properties.