Investigation on the process and microstructure evolution during direct laser metal deposition of 18Ni300
ISSN: 1355-2546
Article publication date: 28 September 2018
Issue publication date: 15 October 2018
Abstract
Purpose
Additive manufacturing is a fabrication technology with flexibility and economy. 18Ni300 is one of maraging steels with ultra-high strength, superior toughness, so it is an excellent candidate of structural material. This paper aims to explore the feasibility of using direct laser metal deposition method to fabricate18Ni300, and the evolution of its microstructure and defects is studied.
Design/methodology/approach
The experiments were conceived from single-trace-single-layer (STSL) test to multi-trace-multi-layers (MTML) test via single-trace-multi-layers (STML) test. The microstructure, defects and mechanical properties were analyzed.
Findings
The STML results showed that the columnar/equiaxed transformation occurred at the top part and the grain size increased with the layer number increasing, and it was explained by an innovative attempt combining columnar/equiaxed transformation model and the change of grain size. The MTML test with the interlayer orthogonal parallel reciprocating scanning pattern resulted in the grain growing along orthogonal directions; with the increase of overlap rate, the length and the area of the columnar grain decreased. What is more, the later deposition layer had lower micro-hardness value because of heat history.
Originality/value
Direct laser metal deposition method was a novel additive manufacturing method to manufacture 18Ni300 components, as 18Ni300 maraging steel was mainly manufactured by selective laser melting (SLM) method nowadays. It was useful to manufacture maraging steel parts using direct laser deposition method because it could manufacture larger parts than SLM method. Influence of processing parameters on forming quality and microstructure evolution was studied. The findings will be helpful to understand the forming mechanism of laser additive manufacturing of 18Ni300 components.
Keywords
Acknowledgements
This work was supported by Shandong Provincial Natural Science Foundation, China under the Grant (No. ZR2017MEE042), Weihai Science and Technology Development Plan under the Grant (No. 2015DXGJMS012) and the National Natural Science Foundation of China under the Grant (No. 51105103).
Citation
Chen, B., Huang, Y., Gu, T., Tan, C. and Feng, J. (2018), "Investigation on the process and microstructure evolution during direct laser metal deposition of 18Ni300", Rapid Prototyping Journal, Vol. 24 No. 6, pp. 964-972. https://doi.org/10.1108/RPJ-01-2018-0022
Publisher
:Emerald Publishing Limited
Copyright © 2018, Emerald Publishing Limited