无损检测（NDT）被广泛用作钢铸件的检验工具。超声波检测（UT）——无损检测的一种形式，是一种检测和确定不连续性大小的复杂方法，从而确定铸件是否符合规定的质量水平。本文描述了UT的方法，展示了其应用和局限性。目的是提高工程师对UT的理解，从而达到工程师预期的质量水平。

NONDESTRUCTIVE TESTING (NDT) IS WIDELY USED AS AN INSPECTION TOOL FOR STEEL CASTINGS. ULTRASONIC TESTING (UT)--A FORM OF NDT, IS A SOPHISTICATED METHOD FOR DETECTING AND SIZING DISCONTINUITIES, THUS DETERMINING WHETHER OR NOT THE CASTINGS MEET THE SPECIFIED QUALITY LEVEL. THE PAPER DESCRIBES METHODS FOR UT SHOWING ITS APPLICATIONS AND LIMITATIONS. THE OBJECTIVE IS TO ENHANCE THE ENGINEER'S UNDERSTANDING OF UT SO THAT THE QUALITY LEVEL EXPECTED BY THE ENGINEER IS MET.