Method of determining grain size using ultrasonic waves
AssigneeNippon Steel Corporation
InventorsHideo Takafuji, Shoichi Sekiguchi
Life of this patent
Estimating the term…
Abstract
The grain size is expressed by the diameter of grains demarcated at high-angle grain boundaries, such as ferrite grains in ferritic steels. Ultrasonic waves having a frequency f are propagated through an object to be examined and its attenuation constant .alpha. is determined. Using the ratio f/.alpha. and equation C'.sub.j .ltoreq.f/.alpha..ltoreq.C'.sub.j+l where C'.sub.j and C'.sub.j+l are constants and j is a constant between 1 and 4, the order j of the region to which the value of f/.alpha. belongs is determined. Then the grain diameter D is derived from equation ##EQU1## using an integer n.sub.j and constant A.sub.j predetermined for the order j of each region.
Claims1
A method of determining grain size using ultrasonic waves which comprises propagating ultrasonic waves having a frequency f through an object to be examined, determining the attenuation constant .alpha. of the ultrasonic waves, determining the order of the region j to which the value of f/.alpha. belongs using the ratio f/.alpha. and equation
- C'.sub.j .ltoreq.f/.alpha..ltoreq.C'.sub.j+1
- where C'.sub.j and C'.sub.j+1 are constants and j is a constant between 1 and 4, and deriving the grain diameter D from equation ##EQU9## using an integer n.sub.j and constant A.sub.j predetermined for the order j of each region.
Dependencies are inferred from the claim text.