Thermal History of HT-9 Weldment Heat-Affected Zones During Welding

摘要

HT-9, a commercial 12Cr-1Mo ferritic steel, is a candidate structural material for fusion reactor first walls. The microstructure in weldments of this material has been observed to vary over short distances as a function of the varying thermal history during welding. An example is the observation of several heat-affected zones over less than a 2.5 mm (0.1 in.) distance from the weld/base metal interface. The mechanical behavior response of ''local'' weldment microstructures can be characterized by simulation of the structure over larger usable volumes of material. This requires precise knowledge of the ''local'' thermal history during welding. An empirical equation for describing the thermal history of HT-9 weldment heat-affected zones during gas tungsten-arc welding is presented in this paper. Both peak temperatures and cool-down cycles, are predictable at any location in the base metal heat-affected zone for welding of plate under heat flow conditions similar to those anticipated for first wall component fabrication, i.e., two-dimensional heat flow. Power input and preheat effects are included in the equation. (ERA citation 11:034275)