Selective laser melting of maraging steel: mechanical properties development and its application in mold
Abstract
Purpose
This paper aims to verify whether selective laser melting (SLM) could be used for manufacturing mold with conformal cooling channels and determine whether the mechanical properties development of SLM manufacturing maraging steel mold would be beneficial to improve the quality of mold.
Design/methodology/approach
A series of block specimens and cylindrical tensile specimens are manufactured by SLM, and then are heat treated by solution treatment (ST) and solution treatment + aging treatment (ST + AT), respectively. The development of microstructure, microhardness and tensile strength of specimens is investigated. Then, a mold with conformal cooling channels is designed and manufactured by SLM and machined after ST with microhardness decreasing.
Findings
The morphology of microstructure varies widely under different heat treatment. The microhardness and tensile strength decrease after ST with cellular structure broken, which is conducive to mechanical finishing for mold to improve surface accuracy. After that, the hardness and strength of the mold increase significantly by AT with the precipitation of Ni3Mo, Fe2Mo and Ni3Ti particles. The maraging steel mold with conformal cooling channels can be manufactured by SLM successfully. And the surface accuracy of mold could be improved easily by machining.
Originality/value
Compared with the traditional mold with simple cooling channels, the mold with conformal cooling channels can be manufactured by SLM directly. The hardness of maraging steel mold manufactured by SLM can be reduced through ST, which is conducive to mechanical finishing for overcoming the defect of low precision of SLM directly manufacturing mold. This provides a new way for manufacturing mold of high quality.
Keywords
Acknowledgements
The work described in this paper was fully supported by these projects: 2014 National Natural Science Foundation of China (Project No.51405160), 2015 Key Projects of Guangdong Province Science and Technology plan (Project No.2015B01012500), 2016 Science and Technology Planning Project of Guangdong Province (Project No.2016B090925002) and 2017 Guangzhou Talent Support for New Star of Pearl River (Project No.201710010064).
Citation
Bai, Y., Yang, Y., Xiao, Z. and Wang, D. (2018), "Selective laser melting of maraging steel: mechanical properties development and its application in mold", Rapid Prototyping Journal, Vol. 24 No. 3, pp. 623-629. https://doi.org/10.1108/RPJ-05-2017-0104
Publisher
:Emerald Publishing Limited
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