Speaker
Ryuji Ohsone
(Japan Atomic Energy Agency)
Description
A hot isostatic pressing(HIP) method is one of the candidate process to fabricate the fusion blanket the first wall with built in cooling channels. Thin plates and rectangular tubes made of reduced activation ferritic/martensitic (RAFM) steel, such as F82H, are consolidated by the HIP method. The first wall quality therefore depends on the integrity of the formed HIP joint. In laboratory scale experiments, electrolytic polishing to HIP bonding surface was performed to remove the machined layer. As the result, the strength of the HIP bonding surfaces was improved. To investigate this reason, oxidations on the HIP joint were analyzed. As a result, it showed that the number of oxidations on the HIP boundary were reduced to approximately 0.5times. So the purposes of this study are to verify feasibility of electrolytic polishing to the large-scale components and to measure the strength distribution of the HIP joints.
Material was F82H steel, which chemical composition was 7.78Cr-1.99W-0.20V-0.03Ta-0.12Mn-0.11Si-0.09C (Fe balance, all wt%). The assembly was then consolidated by HIP at 150MPa for 2hours at 1100°C. After the torsion tests, the fracture surface and cross-sectional HIP interface were observed by scanning electron microscope (SEM). The elemental analysis on the observed inclusions was conducted utilizing transition edge sensor type X-ray analysis system (µ-EDS) assembled to SEM, and field-emission electron prove micro-analyzer (EPMA).
Accordingly, even for large-scale components, it was confirmed that machined layer was removed by electrolytic polishing. And without large deformation due to HIP, Mock-up has been fabricated. Then, the test pieces were machined from the mock-up, torsion tests were conducted. And this topic will be discussed further in this paper
Co-authors
Hiroyasu Tanigawa
(Japan Atomic Energy Agency, Rokkasho-mura, Japan)
Ryuji Ohsone
(Japan Atomic Energy Agency, Rokkasho-mura, Japan)
Takashi Nozawa
(Japan Atomic Energy Agency, Rokkasho-mura, Japan)
