Methods for Determination of Brittle strength parameters of bimetal elements for reactor vessels

To create reliable and safe structures using bimetal materials, such as hull plates with cladding layer being applied to its working surface of austenitic stainless steel, it is necessary to study thoroughly the influence of the difference in the physico-mechanic properties of the components on the state of stress and strain and the resistance to fracture of two-layered composition under static loading. The test results for the specimens of a base metal and the metal with overlay are shown, and the fracture resistance of the bimetal specimens was lower. To analyze the reliability of bimetal materials, structures and machine parts, the value and character of thermoelastic and residual stress distribution in bimetals, the meaning of stress intensity factors for various types of cracks and the temperature dependence of critical meaning for stress intensity factors must be known. The cylindrical elements for reactor vessels are made of the bimetal composition of alloyed steel and corrosion-proof austenitic steel. The problem of the thermoelastically stressed state of bimetal structural elements was solved by mechanical modeling method. (K.I.)