Microstructure estimation and validation of ER110S-G steel structures produced by wire and arc additive manufacturing

Mishra, V.; Babu, A.; Schreurs, R.; Wu, K.; Hermans, M.J.M.; Ayas, C.

doi:10.1016/j.jmrt.2023.01.214

Microstructure estimation and validation of ER110S-G steel structures produced by wire and arc additive manufacturing

Title

Microstructure estimation and validation of ER110S-G steel structures produced by wire and arc additive manufacturing

Author

Mishra, V. (TU Delft Computational Design and Mechanics)
Babu, A. (TU Delft Team Marcel Hermans)
Schreurs, R. (Student TU Delft)
Wu, K. (Student TU Delft)
Hermans, M.J.M. (TU Delft Team Marcel Hermans)
Ayas, C. (TU Delft Computational Design and Mechanics)

Date

2023

Abstract

Wire and Arc Additive Manufacturing (WAAM) emerged as a manufacturing process for large scale structures with extensive form and design freedom. WAAM can be fully exploited once the relation between the transient thermal history and its relation to microstructure development and resultant mechanical properties is established. This relation can be further used for computational design tools such as Topology Optimization. This paper presents a model to predict the relation between the thermal history and solid-state phase transformations in a widely applicable High Strength Low Alloy steel ER110S-G. The transient thermal history of parts manufactured by WAAM is modelled using finite element analysis. The modelled thermal history is validated with thermocouple measurements. Our results show that a critical cooling cycle is responsible for the solid-state phase transformation in an AM part. The cooling rate of this particular cooling cycle is superimposed onto an experimentally constructed Continuous Cooling Transformation (CCT) diagram to determine the local solid-state phase fractions. The predicted phase fractions in three wall samples with different design and processing conditions of AM parts are used to predict the hardness. The predicted hardness is 10% higher than the measured hardness of AM samples. The effect of tempering is also considered in the model through JMAK equation. The results show that the tempering is caused in regions with high martensite content and it lowers the hardness by 8 − 10%. The micrographs of the AM parts show that the microstructural features are same for the AM parts with similar critical cooling rates.

Subject

High Strength Low Alloy (HSLA) steel
Solid state phase transformation
Thermal validation
Wire and Arc Additive Manufacturing (WAAM)

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http://resolver.tudelft.nl/uuid:f02746b8-10a8-45bc-b8fd-3a6efae89e4c

DOI

https://doi.org/10.1016/j.jmrt.2023.01.214

ISSN

2238-7854

Source

Journal of Materials Research and Technology, 23, 3579-3601

Part of collection

Institutional Repository