C.O.D. Toughness Testing of Medium Strength Steel as a Preliminary Development for Single Specimen J Integral Toughness Tests of SA533-B Steel

摘要

The primary purpose of this project is to set up a test facility and to develop the necessary expertise to enable reliable elasto-plastic fracture toughness tests to be performed. Initially, tests are to be conducted on material similar to that used in the Koeberg pressure vessel walls, with the ultimate goal of performing single specimen J integral tests on the pressure vessel steel itself to determine through-thickness toughness variations. The project will comprise a number of stages, each one necessary for the development of the techniques used in J integral testing. These include: (i) development of an appropriate specimen design, of suitable size and shape that is applicable to both crack opening displacement (C.O.D.) and J integral tests; (ii) development, testing and calibration of the necessary associated mechanical and electrical equipment (e.g. clip gauge, amplifiers, interface unit, etc.), with (iii) an estimation of the probable errors and noise levels with a view to their elimantion, leading to (iv) perfection of the sensitivity and reproducibility of, firstly, the multiple specimen C.O.D. technique and, secondly, the multiple specimen J integral techniques. (v) Based on the above techniques, development of the single specimen J integral test method incorporating development of a computerised testing procedure. All the above procedure is to be conducted on similar, but non-Koeberg pressure vessel material ('ROQ Tough'). (vi) Finally, development and testing of both multiple specimen and single specimen J integral tests on actual SA533B material and an investigation of the through thickness toughness and fatigue crack propagation behaviour. (Atomindex citation 15:066635)