AISI/DOE Advanced Process Control Program Vol. 4 of 6: ON-LINE, NON-DESTRUCTIVE MECHANICAL PROPERTY MEASUREMENT USING LASER-ULTRASOUND

Moreau, Andre' ; Lord, Martin ; Levesqure, Daniel ; Dubois, Marc ; Bussiere, Jean ; Monchalin, Jean-Pierre ; Padioleau, Christian ; Lamouche, Guy ; Veres, Teodor ; Viens, Martin ; Hebert, Harold ; Basseras, Pierre ; Jen, Cheng-Kuei

American Iron and Steel Institute

关键词: Tensile Properties;    Mechanical Properties;    Carbon Steels;    Time Delay;    Process Control;   

DOI  :  10.2172/794988
RP-ID  :  DOE/ID/13205
RP-ID  :  FC07-93ID13205
RP-ID  :  794988

美国|英语

来源: UNT Digital Library

【 摘 要 】

The goal of this project was to demonstrate the feasibility to measure the mechanical properties, such as yield strength, tensile strength, elongation, strain hardening exponent and plastic strain ratio parameters, of low carbon steel sheets on the production line using laser ultrasound. The ultrasound generated by the developed apparatus travels mostly back and forth in the thickness of the steel sheet. By measuring the time delay between two echoes, and the relative amplitude of these two echoes, one can measure ultrasound velocity and attenuation. These are governed by the microstructure: grain size, crystallographic texture, dislocations, etc. Thus, by recording the time behavior of the ultrasonic signal, one can extract microstructural information. These microstructural information together with the modified Hall-Petch equation allow measurement of the mechanical properties. Through laboratory investigations with a laboratory laser ultrasound system, followed by the installation of a prototype system at LTV Steel Company's No.1 Inspection Line in Cleveland, all target mechanical properties of ultra low carbon (ULC), low carbon (LC) and high strength low alloy (HSLA) steel sample lots were measured meeting or nearly meeting all the target accuracies. Thus, the project realized its goal to demonstrate that the mechanical properties of low carbon steel sheets can be measured on-line using laser ultrasound