Ultrasonic assessment of material degradation by thermal fatigue

Jorma Pitkänen; Pentti Kauppinen; Harri Jeskanen

Ultrasonic assessment of material degradation by thermal fatigue

Jorma Pitkänen, Pentti Kauppinen, Harri Jeskanen

VTT Technical Research Centre of Finland

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific

Abstract

Near surface areas can contain many types of defects, material changes and degradation. Materials subjected to thermal fatigue or annealing have been evaluated with a special ultrasonic probe optimised for surface measurements, and with a 0 longitudinal wave probe. Combining measured data from a large area and calculating depths of interest in the sound path (RF-signal) information provides improved estimation of degradation levels. The technique is using a combination of three factors: (1) back-scattered ultrasonic signals and induced leaky Rayleigh wave information), and (2) simple statistical data analysis in combination with (3) an optimised ultrasonic transducer. The back-scattered ultrasonic signal is a measure of the effect of geometrical reflectors such as micro-pores, inclusions, precipitates, segregation, micro-cracks and cracks as well as of back-scattering from phase boundaries during fatigue damaging and increase of degradation inside the material. The leaky Rayleigh wave component is sensitive to surface properties, and especially to cracks. Deep cracks will totally cancel the leaky Rayleigh wave signal.

Original language	English
Title of host publication	Competent Design by Castings: Improvements in a Nordic project
Subtitle of host publication	GJUTDESIGN-2005 final seminar
Place of Publication	Espoo
Publisher	VTT Technical Research Centre of Finland
Pages	123-131
ISBN (Electronic)	951-38-6299-2
ISBN (Print)	951-38-6298-4
Publication status	Published - 2005
MoE publication type	B3 Non-refereed article in conference proceedings
Event	Competent Design by Castings: Improvements in a Nordic project : GJUTDESIGN-2005 final seminar - Espoo, Finland Duration: 13 Jun 2005 → 14 Jun 2005

Publication series

Series	VTT Symposium
Number	237
ISSN	0357-9387

Seminar

Seminar	Competent Design by Castings: Improvements in a Nordic project
Country/Territory	Finland
City	Espoo
Period	13/06/05 → 14/06/05

Access to Document

https://publications.vtt.fi/pdf/symposiums/2005/S237.pdf

Cite this

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title = "Ultrasonic assessment of material degradation by thermal fatigue",

abstract = "Near surface areas can contain many types of defects, material changes and degradation. Materials subjected to thermal fatigue or annealing have been evaluated with a special ultrasonic probe optimised for surface measurements, and with a 0 longitudinal wave probe. Combining measured data from a large area and calculating depths of interest in the sound path (RF-signal) information provides improved estimation of degradation levels. The technique is using a combination of three factors: (1) back-scattered ultrasonic signals and induced leaky Rayleigh wave information), and (2) simple statistical data analysis in combination with (3) an optimised ultrasonic transducer. The back-scattered ultrasonic signal is a measure of the effect of geometrical reflectors such as micro-pores, inclusions, precipitates, segregation, micro-cracks and cracks as well as of back-scattering from phase boundaries during fatigue damaging and increase of degradation inside the material. The leaky Rayleigh wave component is sensitive to surface properties, and especially to cracks. Deep cracks will totally cancel the leaky Rayleigh wave signal.",

author = "Jorma Pitk{\"a}nen and Pentti Kauppinen and Harri Jeskanen",

year = "2005",

language = "English",

isbn = "951-38-6298-4",

series = "VTT Symposium",

publisher = "VTT Technical Research Centre of Finland",

number = "237",

pages = "123--131",

booktitle = " Competent Design by Castings: Improvements in a Nordic project",

address = "Finland",

note = "Competent Design by Castings: Improvements in a Nordic project <br/> : GJUTDESIGN-2005 final seminar ; Conference date: 13-06-2005 Through 14-06-2005",

}

Pitkänen, J, Kauppinen, P & Jeskanen, H 2005, Ultrasonic assessment of material degradation by thermal fatigue. in Competent Design by Castings: Improvements in a Nordic project: GJUTDESIGN-2005 final seminar. VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 237, pp. 123-131, Competent Design by Castings: Improvements in a Nordic project
, Espoo, Finland, 13/06/05. <https://publications.vtt.fi/pdf/symposiums/2005/S237.pdf>

Ultrasonic assessment of material degradation by thermal fatigue. / Pitkänen, Jorma; Kauppinen, Pentti; Jeskanen, Harri.
Competent Design by Castings: Improvements in a Nordic project: GJUTDESIGN-2005 final seminar. Espoo: VTT Technical Research Centre of Finland, 2005. p. 123-131 (VTT Symposium; No. 237).

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific

TY - GEN

T1 - Ultrasonic assessment of material degradation by thermal fatigue

AU - Pitkänen, Jorma

AU - Kauppinen, Pentti

AU - Jeskanen, Harri

PY - 2005

Y1 - 2005

N2 - Near surface areas can contain many types of defects, material changes and degradation. Materials subjected to thermal fatigue or annealing have been evaluated with a special ultrasonic probe optimised for surface measurements, and with a 0 longitudinal wave probe. Combining measured data from a large area and calculating depths of interest in the sound path (RF-signal) information provides improved estimation of degradation levels. The technique is using a combination of three factors: (1) back-scattered ultrasonic signals and induced leaky Rayleigh wave information), and (2) simple statistical data analysis in combination with (3) an optimised ultrasonic transducer. The back-scattered ultrasonic signal is a measure of the effect of geometrical reflectors such as micro-pores, inclusions, precipitates, segregation, micro-cracks and cracks as well as of back-scattering from phase boundaries during fatigue damaging and increase of degradation inside the material. The leaky Rayleigh wave component is sensitive to surface properties, and especially to cracks. Deep cracks will totally cancel the leaky Rayleigh wave signal.

AB - Near surface areas can contain many types of defects, material changes and degradation. Materials subjected to thermal fatigue or annealing have been evaluated with a special ultrasonic probe optimised for surface measurements, and with a 0 longitudinal wave probe. Combining measured data from a large area and calculating depths of interest in the sound path (RF-signal) information provides improved estimation of degradation levels. The technique is using a combination of three factors: (1) back-scattered ultrasonic signals and induced leaky Rayleigh wave information), and (2) simple statistical data analysis in combination with (3) an optimised ultrasonic transducer. The back-scattered ultrasonic signal is a measure of the effect of geometrical reflectors such as micro-pores, inclusions, precipitates, segregation, micro-cracks and cracks as well as of back-scattering from phase boundaries during fatigue damaging and increase of degradation inside the material. The leaky Rayleigh wave component is sensitive to surface properties, and especially to cracks. Deep cracks will totally cancel the leaky Rayleigh wave signal.

M3 - Conference article in proceedings

SN - 951-38-6298-4

T3 - VTT Symposium

SP - 123

EP - 131

BT - Competent Design by Castings: Improvements in a Nordic project

PB - VTT Technical Research Centre of Finland

CY - Espoo

T2 - Competent Design by Castings: Improvements in a Nordic project <br/>

Y2 - 13 June 2005 through 14 June 2005

ER -

Ultrasonic assessment of material degradation by thermal fatigue

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Seminar

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