【国外标准】 Standard Guide for Reconstitution of Charpy-Sized Specimens

3.1 Practice E185 defines the minimum requirements for light-water reactor surveillance program Charpy V-notch specimens and Practice E2215 describes the evaluation of test specimens from surveillance capsules. It may be desirable to extend the original surveillance program with additional specimens for plant aging management issues, such as plant license renewal, to better define existing data, or to determine fracture toughness of a material when no standard fracture toughness test specimens are available. The possibility to reconstitute the broken halves of existing specimens can provide specimens which can be tested.3.2 Charpy-sized specimens are typically machined from material not previously mechanically tested. There are occasions that exist when either (1) no full size specimen blanks are available or (2) the material available with the desired history (such as having been subjected to irradiation) is not sufficient for the machining of full-size specimens, or both.3.3 A solution to this problem, which is addressed in this guide, is to fabricate new specimens using the broken halves of previously tested Charpy-sized specimens or other pieces of ferritic steel too small to fabricate a full Charpy-sized specimen. In this guide, the central segment of each new specimen utilizes a broken half of a previously tested specimen and end tabs that are welded to the central segment, or the central section may simply be a piece of untested material shorter than a Charpy-sized specimen. While specifically addressing reconstitution of irradiated pressure vessel steels, this guide can also provide guidance for reconstitution of Charpy-sized specimens for other situations where material availability is limited.1.1 This guide covers procedures for the reconstitution of ferritic steel, Type A Charpy V-notch specimens (Test Methods E23) and Charpy-sized fracture toughness specimens suitable for testing in three point bending in accordance with Test Methods E1921 or E1820. Ferritic steels (principally broken specimens used in nuclear power plant irradiation programs) are reconstituted by welding end tabs of similar material onto remachined specimen sections that were unaffected by the initial test. Guidelines are given for the selection of suitable specimen halves and end tab materials, for dimensional control, and for avoidance of overheating the notch area. A comprehensive overview of the reconstitution methodologies can be found in Ref (1).21.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.