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1. (WO1998052032) METHOD FOR RESIDUAL STRESS MEASURING

Pub. No.:    WO/1998/052032    International Application No.:    PCT/EP1998/003003
Publication Date: Fri Nov 20 00:59:59 CET 1998 International Filing Date: Sat May 16 01:59:59 CEST 1998
IPC: G01N 29/07
G01N 29/11
G01N 29/30
G01N 29/34
G01N 29/38
G01N 29/40
G01N 29/42
G01N 29/46
G01N 29/50
Applicants: HOOGOVENS ALUMINIUM WALZPRODUKTE GMBH
HASZLER, Alfred, Johann, Peter
GHAZIARY, Hormoz
Inventors: HASZLER, Alfred, Johann, Peter
GHAZIARY, Hormoz
Title: METHOD FOR RESIDUAL STRESS MEASURING
Abstract:
Method for measuring residual stress in a metallic specimen wherein, by means of an ultrasound transducer an ultrasound entry wave having a ground frequency is introduced into a surface of the metallic specimen, the ultrasound entry wave is measured by means of an entry wave detector and the succeeding ultrasound exit wave is measured by means of an exit wave detector and the measured values of the ultrasound entry and exit wave are used to determine residual stress, characterized in that, for a selected entry gate time the value of the entry convolution integral of the measured ultrasound entry wave and a periodic wave of the ground frequency is calculated and during a selected exit gate time the value of the exit convolution integral of the measured ultrasound exit wave and a periodic wave of the ground frequency is calculated and the residual stress is determined using the calculated values of the entry convolution integral and the exit convolution integral.