Fracture toughness of 15X2HMFA steel and its welds

Abstract

The generalized experimental fracture toughness results of industrial semi-products, made from CrNiMoV steel and intended for VVER-1000 reactor pressure vessel manufacture, are presented. On the base of test results of nine steel heats having a common purity (sulfur to 0.018%; phosphorus to 0.015%; and copper to 0.20%) and of the same number of heats having a higher purity (sulfur to 0.012%; phosphorus to 0.012%; and copper to 0.06%) the fracture toughness temperature dependences were constructed. These differ appreciably from the reference curves for this material according to PNAE G-7-002-86. The temperature dependences K1c for 15X2HMFA steel welds were also obtained. By this, for welds produced using manual arc welding and the types RT-45A and RT-45B electrodes as well as electroslag welding with Sv-16X2HMFTA wire and OF-6 flux, these dependences were constructed on the limited number of welded samples, as these welding methods are, practically, not used in the manufacture of such reactors. The fracture toughness assessment for welds produced by submerged arc welding was carried out for two variants of production processing (Sv-10XGNMAA wire and AH-17M flux; Sv-08XGHMTA wire and NF-18M flux), which were applied in the fabrication of circumferential welds for a VVER-1000 reactor.