铸铁基体及石墨形状超声波无损伤检验探讨

利用超声波（速度和强度）来测试铸铁中不同的石墨形状参数、基体结构及与此相关的机械性能。结果表明，石墨形状参数和超声波速度有着明显的对应关系，但是基体与超声波之间的影响则不明显。随着石墨形状参数的增加，超声波的幅值也随之变化，发现铁素体、珠光体、正火马氏体和贝氏体有相同的特性，但是基体中较大数量的正火马氏体或珠光体都会导致超声波幅值的增大。

Ultrasonic Non destructive Evaluation of the Matrix Structure and the Graphite Shape in Cast Iron

The purpose of this investigation was to determine the ultrasonic characteristics (velocity and attenuation) of cast irons with different nodularities and matrix structures, and to correlate these with mechanical properties. The results indicated that there was a definite relationship between the degree of nodularity of graphite and the ultrasonic velocity, but the influences of matrix structure on the ultrasonic velocity was not clear. The attenuation of the ultrasonic amplitude increased with decreasing nodularity. Ferritic, pearlitic, tempered martensitic and bainitic matrix structures were found to have similar attenuation characteristics, but greater amounts of tempered martensite or pearlite resulted greater attenuation.