Testing large-size bodies made of WWER-1000 pressure vessel material

The results are summarized of tests on large-size test bodies made of the 15Kh2NMFA steel used in the manufacture of WWER-1000 pressure vessels, as well as of their welds obtained by electroslag and submerged arc welding. The nominal thickness of the bodies was 150 mm, surface defects were located in the base material perpendicularly to the direction of the maximum forming or in the filler metal parallel to the longitudinal axis of the weld. The tests were performed mainly at room temperature on a ZZ-8000 test facility; additional tests were carried out on VRD-500 and VRD-1500 rotary devices for disk tests (diameters up to 400 and 650 mm, respectively). The tests revealed that the critical stress for the initiation of subcritical crack growth or of final damage, for defects smaller than about 20 to 30 mm of depth, is roughly at the yield point or breaking strength level, respectively, of the material under study. (Z.M.). 4 figs., 1 tab