Modelling the effect of coating on the stresses and microstructure evolution in chill casting of wind turbine main shafts

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The purpose of the present work is to quantify the effect of the inside coating on chills for casting of large wind turbine main shafts with respect to the evolution of internal stresses. These are known to affect the lifetime of the chills, and this is a major cost for the foundries today. Simulations of the casting process are performed with four different heat transfer coefficients (HTCs) between the casting and the chill, and the resulting transient stress fields are reported in the chill. The microstructural evolution in the casting in terms of the nodule count is also modelled in the simulations. The outcome is validated by comparisons with samples taken out from a critical region of main shafts cast in sand and in chills. The results reveal minor reductions in the maximum principal stresses on the inner and outer surfaces of the chill of 3.1% and 18.5%, respectively, from changing the HTC from 2000 to 500 W m−2 K−1. These results indicate that the lifetime of the chill will not be significantly improved by adding a thicker layer of coating. The microstructure evolution is not very much affected by the HTC value with a maximum reduction in nodule count of 6.5%. Therefore, it is concluded that the material quality obtained from casting the main shafts in chills (and hence the performance of the part) is still much better than for sand casting, even though a very thick layer of coating is applied. Copyright © 2017 John Wiley & Sons, Ltd.
Original languageEnglish
JournalWind Energy
Volume20
Issue number9
Pages (from-to)1635-1643
Number of pages9
ISSN1095-4244
DOIs
Publication statusPublished - 2017

Keywords

  • Chill casting
  • Coating
  • Ductile cast iron
  • Stresses
  • Wind turbine main shaft

Cite this

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title = "Modelling the effect of coating on the stresses and microstructure evolution in chill casting of wind turbine main shafts",
abstract = "The purpose of the present work is to quantify the effect of the inside coating on chills for casting of large wind turbine main shafts with respect to the evolution of internal stresses. These are known to affect the lifetime of the chills, and this is a major cost for the foundries today. Simulations of the casting process are performed with four different heat transfer coefficients (HTCs) between the casting and the chill, and the resulting transient stress fields are reported in the chill. The microstructural evolution in the casting in terms of the nodule count is also modelled in the simulations. The outcome is validated by comparisons with samples taken out from a critical region of main shafts cast in sand and in chills. The results reveal minor reductions in the maximum principal stresses on the inner and outer surfaces of the chill of 3.1{\%} and 18.5{\%}, respectively, from changing the HTC from 2000 to 500 W m−2 K−1. These results indicate that the lifetime of the chill will not be significantly improved by adding a thicker layer of coating. The microstructure evolution is not very much affected by the HTC value with a maximum reduction in nodule count of 6.5{\%}. Therefore, it is concluded that the material quality obtained from casting the main shafts in chills (and hence the performance of the part) is still much better than for sand casting, even though a very thick layer of coating is applied. Copyright {\circledC} 2017 John Wiley & Sons, Ltd.",
keywords = "Chill casting, Coating, Ductile cast iron, Stresses, Wind turbine main shaft",
author = "Sonne, {Mads Rostgaard} and J. Thorborg and Hattel, {Jesper Henri}",
year = "2017",
doi = "10.1002/we.2114",
language = "English",
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pages = "1635--1643",
journal = "Wind Energy",
issn = "1095-4244",
publisher = "JohnWiley & Sons Ltd.",
number = "9",

}

Modelling the effect of coating on the stresses and microstructure evolution in chill casting of wind turbine main shafts. / Sonne, Mads Rostgaard; Thorborg, J.; Hattel, Jesper Henri.

In: Wind Energy, Vol. 20, No. 9, 2017, p. 1635-1643.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Modelling the effect of coating on the stresses and microstructure evolution in chill casting of wind turbine main shafts

AU - Sonne, Mads Rostgaard

AU - Thorborg, J.

AU - Hattel, Jesper Henri

PY - 2017

Y1 - 2017

N2 - The purpose of the present work is to quantify the effect of the inside coating on chills for casting of large wind turbine main shafts with respect to the evolution of internal stresses. These are known to affect the lifetime of the chills, and this is a major cost for the foundries today. Simulations of the casting process are performed with four different heat transfer coefficients (HTCs) between the casting and the chill, and the resulting transient stress fields are reported in the chill. The microstructural evolution in the casting in terms of the nodule count is also modelled in the simulations. The outcome is validated by comparisons with samples taken out from a critical region of main shafts cast in sand and in chills. The results reveal minor reductions in the maximum principal stresses on the inner and outer surfaces of the chill of 3.1% and 18.5%, respectively, from changing the HTC from 2000 to 500 W m−2 K−1. These results indicate that the lifetime of the chill will not be significantly improved by adding a thicker layer of coating. The microstructure evolution is not very much affected by the HTC value with a maximum reduction in nodule count of 6.5%. Therefore, it is concluded that the material quality obtained from casting the main shafts in chills (and hence the performance of the part) is still much better than for sand casting, even though a very thick layer of coating is applied. Copyright © 2017 John Wiley & Sons, Ltd.

AB - The purpose of the present work is to quantify the effect of the inside coating on chills for casting of large wind turbine main shafts with respect to the evolution of internal stresses. These are known to affect the lifetime of the chills, and this is a major cost for the foundries today. Simulations of the casting process are performed with four different heat transfer coefficients (HTCs) between the casting and the chill, and the resulting transient stress fields are reported in the chill. The microstructural evolution in the casting in terms of the nodule count is also modelled in the simulations. The outcome is validated by comparisons with samples taken out from a critical region of main shafts cast in sand and in chills. The results reveal minor reductions in the maximum principal stresses on the inner and outer surfaces of the chill of 3.1% and 18.5%, respectively, from changing the HTC from 2000 to 500 W m−2 K−1. These results indicate that the lifetime of the chill will not be significantly improved by adding a thicker layer of coating. The microstructure evolution is not very much affected by the HTC value with a maximum reduction in nodule count of 6.5%. Therefore, it is concluded that the material quality obtained from casting the main shafts in chills (and hence the performance of the part) is still much better than for sand casting, even though a very thick layer of coating is applied. Copyright © 2017 John Wiley & Sons, Ltd.

KW - Chill casting

KW - Coating

KW - Ductile cast iron

KW - Stresses

KW - Wind turbine main shaft

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