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Onset of the degradation of CVD α-Al2O3 coating during turning of Ca-treated steels

Bjerke, Axel LU orcid ; Hrechuk, Andrii LU orcid ; Lenrick, Filip LU orcid ; M'Saoubi, Rachid ; Larsson, Henrik ; Markström, Andreas ; Björk, Thomas ; Norgren, Susanne LU ; Ståhl, Jan Eric LU and Bushlya, Volodymyr LU (2021) In Wear 477.
Abstract

The ability to control the shape, distribution and composition of non-metallic inclusions has had an important impact on many aspects of steel making. One such impact is on the machinability. Ca-treatments have shown to be able to reduce the abrasiveness of oxide inclusions, improve chip-breaking and lead to formation of deposits that reduce tool wear. However, machining Ca-treated steels with Al2O3 coated cemented carbide tools has not been as advantageous as expected. This study investigates the mechanisms behind the anomalous wear of Al2O3 coatings when turning soft Ca-treated steels. Longitudinal turning tests at a range of speeds (vc = 100–600 m/min) show rapid localized... (More)

The ability to control the shape, distribution and composition of non-metallic inclusions has had an important impact on many aspects of steel making. One such impact is on the machinability. Ca-treatments have shown to be able to reduce the abrasiveness of oxide inclusions, improve chip-breaking and lead to formation of deposits that reduce tool wear. However, machining Ca-treated steels with Al2O3 coated cemented carbide tools has not been as advantageous as expected. This study investigates the mechanisms behind the anomalous wear of Al2O3 coatings when turning soft Ca-treated steels. Longitudinal turning tests at a range of speeds (vc = 100–600 m/min) show rapid localized degradation of the Al2O3 coating limited to the sliding zone. Detailed analysis of the degradation mechanisms was performed using scanning and transmission electron microscopy. The results demonstrate a presence of chemical interactions between the alumina coating and non-metallic inclusions. The interaction resulted in the formation of mainly calcium aluminates and partly alumina-magnesia spinel. In-operando infrared thermography measurements indicate cutting temperatures of 850–1000 °C. Thermodynamic calculations give that CaO and MgO readily reacts with Al2O3, while the reaction with CaS requires presence of additional oxygen at these cutting conditions. Additional turning experiments investigate the influence of oxygen by controlling the cutting environment by adding oxygen (compressed air) or removing oxygen (supply argon). These additional tests show that the presence of additional oxygen has a limited impact on the possible Ca–Al2O3 interaction. This demonstrat a potential for further machinability improvements by controlling the chemical interaction between Ca and Mg based non-metallic inclusions and alumina coatings.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cutting tools, CVD coatings, Electron microscopy, Optical microscopy, Steel, Wear modelling
in
Wear
volume
477
article number
203785
publisher
Elsevier
external identifiers
  • scopus:85103711450
ISSN
0043-1648
DOI
10.1016/j.wear.2021.203785
language
English
LU publication?
yes
additional info
Funding Information: This work was funded by the national strategic innovation program: National action for metallic materials, organized by Vinnova and Jernkontoret (Sweden) under DEMO project (ID 2017?02915). The authors would like to acknowledge the Sustainable Production Initiative (SPI) - a cooperation between Lund University and Chalmers University of Technology. The acknowledgment also extends to Per Alm and Vyacheslav Kryzhanivskyy (Seco Tools AB) for the help with IR thermography. Funding Information: This work was funded by the national strategic innovation program: National action for metallic materials , organized by Vinnova and Jernkontoret (Sweden) under DEMO project (ID 2017–02915 ). The authors would like to acknowledge the Sustainable Production Initiative (SPI) - a cooperation between Lund University and Chalmers University of Technology. The acknowledgment also extends to Per Alm and Vyacheslav Kryzhanivskyy (Seco Tools AB) for the help with IR thermography. Publisher Copyright: © 2021 The Author(s) Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
id
347899e7-106b-425b-b4bc-ce99a94f34fb
date added to LUP
2021-04-16 09:05:22
date last changed
2024-03-08 11:11:14
@article{347899e7-106b-425b-b4bc-ce99a94f34fb,
  abstract     = {{<p>The ability to control the shape, distribution and composition of non-metallic inclusions has had an important impact on many aspects of steel making. One such impact is on the machinability. Ca-treatments have shown to be able to reduce the abrasiveness of oxide inclusions, improve chip-breaking and lead to formation of deposits that reduce tool wear. However, machining Ca-treated steels with Al<sub>2</sub>O<sub>3</sub> coated cemented carbide tools has not been as advantageous as expected. This study investigates the mechanisms behind the anomalous wear of Al<sub>2</sub>O<sub>3</sub> coatings when turning soft Ca-treated steels. Longitudinal turning tests at a range of speeds (v<sub>c</sub> = 100–600 m/min) show rapid localized degradation of the Al<sub>2</sub>O<sub>3</sub> coating limited to the sliding zone. Detailed analysis of the degradation mechanisms was performed using scanning and transmission electron microscopy. The results demonstrate a presence of chemical interactions between the alumina coating and non-metallic inclusions. The interaction resulted in the formation of mainly calcium aluminates and partly alumina-magnesia spinel. In-operando infrared thermography measurements indicate cutting temperatures of 850–1000 °C. Thermodynamic calculations give that CaO and MgO readily reacts with Al<sub>2</sub>O<sub>3</sub>, while the reaction with CaS requires presence of additional oxygen at these cutting conditions. Additional turning experiments investigate the influence of oxygen by controlling the cutting environment by adding oxygen (compressed air) or removing oxygen (supply argon). These additional tests show that the presence of additional oxygen has a limited impact on the possible Ca–Al<sub>2</sub>O<sub>3</sub> interaction. This demonstrat a potential for further machinability improvements by controlling the chemical interaction between Ca and Mg based non-metallic inclusions and alumina coatings.</p>}},
  author       = {{Bjerke, Axel and Hrechuk, Andrii and Lenrick, Filip and M'Saoubi, Rachid and Larsson, Henrik and Markström, Andreas and Björk, Thomas and Norgren, Susanne and Ståhl, Jan Eric and Bushlya, Volodymyr}},
  issn         = {{0043-1648}},
  keywords     = {{Cutting tools; CVD coatings; Electron microscopy; Optical microscopy; Steel; Wear modelling}},
  language     = {{eng}},
  month        = {{07}},
  publisher    = {{Elsevier}},
  series       = {{Wear}},
  title        = {{Onset of the degradation of CVD α-Al2O3 coating during turning of Ca-treated steels}},
  url          = {{http://dx.doi.org/10.1016/j.wear.2021.203785}},
  doi          = {{10.1016/j.wear.2021.203785}},
  volume       = {{477}},
  year         = {{2021}},
}