Alloy 800 mechanical properties data and design code requirements

Mechanical property data needs are considered in terms of design code requirements for nuclear applications in the UK. Two situations are considered, one being a high carbon Grade 2 alloy for HTR applications, and the other being a low carbon Grade 1 alloy for CFR applications. It is shown that, although most data exist for the Grade 2 alloy which is coded ASME Code Case 1952, a number of areas require further study before this alloy can be specified with confidence for HTR applications. These areas include the more extensive provision of combined creep/high strain fatigue data, a study of factors affecting the creep rupture ductility and evaluation of the effect of environment on the mechanical properties. In the case of low carbon Grade 1 material an extensive data collection programme would be necessary in the temperature range 500 to 550degC before the properties of this alloy could be reliably specified for CFR application. (author)