Effects of Tube Drawing on Structural Material for ITER Test Blanket Module

A detailed study was conducted on the first wall fabrication process using the reduced activation ferritic/martensitic steel that will be used to fabricate ITER test blanket modules. The effects of the tube-drawing process on microstructural and mechanical properties of F82H is one of the most important issues for fabrication of the module. Square tubes with [hollow square]11 mm × 1.5^T (thickness) mm × 3500^L (length) mm have been developed by a cold-rolling method. This tube is long enough to fabricate the first wall without any joint in the cooling path. Its surface roughness (Rz) and outer curvature are less than 1 m and 1.4 mm, respectively. Dimensions were accurate enough to reduce the assembly gap for a Hot Isostatic Pressing (HIP) joint. Although the rolling process introduced an elongated microstructure containing dense precipitates, this anisotropic microstructure was successfully recovered by heat treatments corresponding to that used in the HIP process. This work demonstrated that the drawing process could be applicable to a fabrication process for the breeding-blanket component.