Heat Treatment Behavior of the 18Ni300 Maraging Steel Additively Manufactured by Selective Laser Melting

2018 ◽  
Vol 941 ◽  
pp. 2160-2166 ◽  
Author(s):  
W.F. Guo ◽  
C. Guo ◽  
Qiang Zhu
Keyword(s):  
Heat Treatment ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Aging Treatment ◽  
Casting Process ◽  
Age Hardening ◽  
Laser Melting ◽  
Reverted Austenite ◽  
And Performance ◽  
Evolution Of Microstructure

The steel 18Ni300 is widely used for tooling of injection moulding and die casting industries. Additive manufacturing (AM) technology is applicable to manufacture dies with “ideal” design without construction of manufacturing reality. Selective laser melting (SLM) processed materials have finer microstructure due to steeper temperature gradient and more rapid cooling conditions than conventional casting process during solidification. This difference may make different heat treatment behavior in obtaining optimal properties of the 18Ni300 maraging steel manufactured by SLM. Heat treatment is one of the most processes to improve microstructure, mechanical properties and performance of tooling dies. This work studies evolution of microstructure and properties during heat treatment, by X-ray diffraction, optical and scanning electron microscopy (SEM). The results show that the SLMed materials with only aging treatment have comparable strengths and hardness to those of conventionally cast materials with both solution and aging treatment. For the SLMed materials, with increase of aging time and/or temperature, the formed reverted austenite (γ-Fe) fraction increases, while aging precipitation hardening decreases. This is more apparent at aging temperatures of higher than 540°C. The combined effects of softening by formation of reverted austenite (γ-Fe) and age hardening induced by precipitation are discussed.

scholarly journals Selective Laser Melting of 18NI-300 Maraging Steel

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4268 ◽  
Author(s):  
Mariusz Król ◽  
Przemysław Snopiński ◽  
Jiří Hajnyš ◽  
Marek Pagáč ◽  
Dariusz Łukowiec
Keyword(s):  
Relative Density ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Aging Treatment ◽  
Steel Powder ◽  
Process Conditions ◽  
Laser Melting ◽  
Microstructure Observation ◽  
High Relative Density ◽  
Wide Range

In the present study, 18% Ni 300 maraging steel powder was processed using a selective laser melting (SLM) technique to study porosity variations, microstructure, and hardness using various process conditions, while maintaining a constant level of energy density. Nowadays, there is wide range of utilization of metal technologies and its products can obtain high relative density. A dilatometry study revealed that, through heating cycles, two solid-state effects took place, i.e., precipitation of intermetallic compounds and the reversion of martensite to austenite. During the cooling process, one reaction took place (i.e., martensitic transformation), which was confirmed by microstructure observation. The improvements in the Rockwell hardness of the analyzed material from 42 ± 2 to 52 ± 0.5 HRC was improved as a result of aging treatment at 480 °C for 5 h. The results revealed that the relative density increased using laser speed (340 mm/s), layer thickness (30 µm), and hatch distance (120 µm). Relative density was found approximately 99.3%. Knowledge about the influence of individual parameters in the SLM process on porosity will enable potential manufacturers to produce high quality components with desired properties.

scholarly journals High Strength X3NiCoMoTi 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4174 ◽  
Author(s):  
Angelina Strakosova ◽  
Jiří Kubásek ◽  
Alena Michalcová ◽  
Filip Průša ◽  
Dalibor Vojtěch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
High Strength ◽  
Industrial Applications ◽  
Tensile Yield Strength ◽  
Laser Melting ◽  
Maraging Steels ◽  
3D Printed

Maraging steels are generally characterized by excellent mechanical properties, which make them ideal for various industrial applications. The application field can be further extended by using selective laser melting (SLM) for additive manufacturing of shape complicated products. However, the final mechanical properties are strongly related to the microstructure conditions. The present work studies the effect of heat treatment on the microstructure and mechanical properties of 3D printed samples prepared from powder of high-strength X3NiCoMoTi 18-9-5 maraging steel. It was found that the as-printed material had quite low mechanical properties. After sufficient heat treatment, the hardness of the material increased from 350 to 620 HV0.1 and the tensile yield strength increased from 1000 MPa up to 2000 MPa. In addition, 3% ductility was maintained. This behavior was primarily affected by strong precipitation during processing.

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