Investigation on the possibility of using the microshear test as a surveillance method to estimate the mechanical properties and fracture toughness of nuclear pressure vessel steel, A508CL3, and its joints welded by narrow-gap submerged-arc welding

The present paper has investigated the mechanical properties of nuclear pre ssure vessel steel, A508CL3, and its welded joints by using the microshear test method, and the fracture toughness of A508CL3 steel and its welds has also been estimated. Moreover, a comparison has been carried out between th e conventional test, microshear test and fracture mechanics test. In additi on, the possibility of using the microshear test on the surveillance progra m of nuclear pressure vessel embrittlement due to neutron irradiation has a lso been considered in detail, and the results indicate that the microshear test can be used successfully to estimate the degradation of mechanical pr operties both for A508CL3 steel and its welded joints. It has been found th at the lower the microshear toughness, the smaller the Charpy V-notch (CVN) impact toughness and fracture toughness, as well as the tearing modulus. F inally, the results show that the microshear test method may be developed a s a supplemental test method or standard of ASTM E185 and E636. (C) 1999 Pu blished by Elsevier Science Ltd. All rights reserved.