View in EDS

Inclusion evolution in additive manufactured 316L stainless steel by laser metal deposition process.

Saved in:
Bibliographic Details
Title: Inclusion evolution in additive manufactured 316L stainless steel by laser metal deposition process.
Authors: Eo, Du-Rim1, Park, Sun-Hong2, Cho, Jung-Wook1 jungwook@postech.ac.kr
Source: Materials & Design. Oct2018, Vol. 155, p212-219. 8p.
Subjects: Laser deposition, Laser plasmas, Laser beams, Stainless steel, Strength of materials, Oxidation kinetics
Abstract: In laser metal deposition (LMD) process, meltpool oxidation is inevitable due to high working temperature, which results in finely dispersed non-metallic inclusions in the steel matrix. In this paper, characteristics of these inclusion, such as number density and mean radius, were controlled by means of changing process parameters, for instance, scan speed and laser power, using AISI 316L stainless steel powders. Subsequently, the yield stress of cast samples from each condition was measured in order to investigate the possibility of utilizing these inclusions in material strengthening. As oxygen contents varied from 306 ppm to 994 ppm, number densities of inclusion varied from 16,900/mm 2 to 34,000/mm 2 . The yield stress of deposited material was proportional to inclusion number density ranging from 218 MPa to 269 MPa. Oxygen contents were governed by beam intensity and deoxidizer compositions in the powder, while faster scan speed gave smaller inclusion diameter due to shorter time for growth. The composition and viscosity of slag layer, which covered interface between superheated meltpool and atmosphere, brought in a large difference in oxidation kinetic. Compared with conventional casting process, a large number of inclusions were more finely distributed and possess smaller size, meaning that oxide metallurgy can be fully utilized in the LMD process. [ABSTRACT FROM AUTHOR]
Copyright of Materials & Design is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:In laser metal deposition (LMD) process, meltpool oxidation is inevitable due to high working temperature, which results in finely dispersed non-metallic inclusions in the steel matrix. In this paper, characteristics of these inclusion, such as number density and mean radius, were controlled by means of changing process parameters, for instance, scan speed and laser power, using AISI 316L stainless steel powders. Subsequently, the yield stress of cast samples from each condition was measured in order to investigate the possibility of utilizing these inclusions in material strengthening. As oxygen contents varied from 306 ppm to 994 ppm, number densities of inclusion varied from 16,900/mm 2 to 34,000/mm 2 . The yield stress of deposited material was proportional to inclusion number density ranging from 218 MPa to 269 MPa. Oxygen contents were governed by beam intensity and deoxidizer compositions in the powder, while faster scan speed gave smaller inclusion diameter due to shorter time for growth. The composition and viscosity of slag layer, which covered interface between superheated meltpool and atmosphere, brought in a large difference in oxidation kinetic. Compared with conventional casting process, a large number of inclusions were more finely distributed and possess smaller size, meaning that oxide metallurgy can be fully utilized in the LMD process. [ABSTRACT FROM AUTHOR]
ISSN:02641275
DOI:10.1016/j.matdes.2018.06.001