Thermo-ultrasound method for determining the damage of structural material

Alexander Gonchar,Konstantin Kurashkin,Vasily Mishakin,S Bratan,S Leonov,S Gorbatyuk,S Roshchupkin

doi:10.1051/matecconf/201822402027

Abstract

The effect of plastic strain and temperature on the longitudinal and shear waves velocity of austenitic stainless steel 12Kh18N10T (analogue AISI 321) is investigated. Cryogenic corrosion-resistant austenitic steel 12Kh18N10T is interesting due to the fact, that during plastic deformation a martensitic phase is formed. The martensitic phase significantly changes the electromagnetic, elastic and strength properties of the entire material. The formation of a new phase in conjunction with the process of plastic deformation has a significant effect on the temperature dependence of the elastic wave velocity. As a result of the studies, numerical values of the temperature-velocity factor for longitudinal and shear ultrasonic waves in steel 12Kh18N10T were obtained. The relationship between changes of the magnetic phase and temperature-velocity factor is suggested; it can be used for determining the material damage by the ultrasound method.

Highlights

Operation of equipment in difficult climatic conditions of the Arctic and the Far North sets specific requirements for the diagnostics of the structural elements state using nondestructive testing methods
The damage of material, for example, under plastic deformation, can significantly affect the acoustic characteristics and the temperature dependence of elastic waves velocities, which leads to an increase in the error in the flaw detection of products [2]
The slopes and the free term of the curves depend on the plastic strain

Summary

Introduction

Operation of equipment in difficult climatic conditions of the Arctic and the Far North sets specific requirements for the diagnostics of the structural elements state using nondestructive testing methods. Investigation of the effect of negative temperatures on acoustic characteristics is necessary to improve the accuracy of determining the location and size of defects in ultrasound [1]. The damage of material, for example, under plastic deformation, can significantly affect the acoustic characteristics and the temperature dependence of elastic waves velocities, which leads to an increase in the error in the flaw detection of products [2]. It is known that during the operation of structures under mechanical loads, accumulation of microdamages in the form of micropores, microcracks, etc. That leads to a change in the elastic and acoustic properties [3, 4]. The change in temperature has a significant effect on the elastic modulus of metals and their alloys [5,6,7,8]

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