| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for evaluating a cleanness of metal materials which meets to greatly improve the cleanness of metal materials such as steels. SOLUTION: N specimens are collected from the metal material to be analyzed. A filler is made to float by an electron beam dissolution method for each specimen. Irradiating electron beams is stopped immediately before a coagulation aggregation start time Tc of the floating filler, and a maximum filler diameter of each specimen after dissolved is measured. The maximum filler diameter aj (j=1, n) is obtained for n specimens. An estimated maximum filler diameter amax in the metal material to be analyzed is calculated by the following expressions (1) and (1') from the maximum filler diameter aj (j=1, n), whereby the cleanness of the metal material to be analyzed is evaluated. [Expression 1] A linear regression expression of the maximum filler diameter aj (j=1, n) and a standardized variable Yj (j=1, n): a=ty+u...(1) wherein n=number of inspection times, the standardized variable yj =-1n[-1n j/(n+1)}] (j=1, n), t=regression coefficient and u=constant. [Expression 1'] A calculation expression (regression expression) of the estimated maximum filler diameter amax in the metal to be analyzed: amax =txymax +u...(1') wherein V0 =inspection reference volume (mm<3> ), V=volume to be estimated (mm<3> ), T (recurrence period)=(V+V0 )/V0 and ymax (standardized variable)=-1n[-1n T-1)/T}].</p> |
