1969年10月之前，PVRC压力部件无损检测小组委员会第四工作组制定了PVRC规范3号，标题为“锻件的超声波检测”到1969年10月27日，本规范的第一次修订已经完成，并已发送给工作组成员进行评估和评论。第一版与原规范的不同之处主要在于，对于较短的测试距离，使用了侧钻孔（SDH）校准标准，对于较长的测试距离，使用了背反射（BR）校准方法。 此外，还制造了两个大型校准试块，即伯利恒钢铁公司生产的1号PVRC参考试块和Midvale-Heppenstall公司生产的2号PVRC参考试块，以便与修订版I一起使用。 在收到关于修订版I的评估和意见后，认为有必要准备第二次修订。到1970年10月29日，第四工作组成员编制了第二版。第二版与第一版的区别主要在于措辞澄清，而不是规范的基本程序。 第二版作为附件一包含在本报告中。 本报告旨在审查、分析第四工作组成员为测试PVRC第3号规范第一版和第二版所允许程序的有效性而开发的数据，并从中得出结论。该报告完全基于以下文件:第四工作组进度报告，PVRC压力部件无损检测小组委员会锻件检查，1972年9月20日。

Prior to October, 1969, Task Group IV of the PVRC Subcommittee on Nondestructive Examination of Pressure Components had formulated PVRC Specification No. 3 entitled "Ultrasonic Examination of Forgings." By October 27, 1969, the first revision of this specification had been developed, and was sent to the Task Group members for their evaluation and comments. Revision I differed from the original specification primarily in the use of a side-drill-hole (SDH) calibration standard for shorter test distances and a backreflection (BR) calibration method for longer test distances. In addition, two large calibration blocks, PVRC Reference Block No. 1 by the Bethlehem Steel Corporation and PVRC Reference Block No. 2 by the Midvale- Heppenstall Company, were fabricated for use in conjunction with Revision I. After the evaluations and comments on Revision I had been received, it was deemed necessary to prepare a second revision. By October 29, 1970, Revision II had been developed by the Task Group IV members. Revision II differed from Revision I primarily in wording clarifications and not in the basic procedures of the specification. Revision II is included with this report as Attachment I. It is the purpose of this report to review, analyze and draw conclusions from data developed by Task Group IV members in efforts to test the validity of the procedures allowed by PVRC Specification No. 3, Revisions I and II. The report is based entirely on the document: Progress Report of Task Group IV, Examination of Forgings of the PVRC Subcommittee on Nondestructive Examination of Pressure Components, September 20, 1972.