SCC crack prpagation conditions studied using three-dimensional microstructural characterization and stress measurements

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360286
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: Ibaraki University
• Principal Investigator: TOMOTA YO 茨城大学, 理工学研究科, 名誉教授 (90007782)
• Co-Investigator(Kenkyū-buntansha): SUZUKI Tetsuya 茨城大学, 工学部, 教授 (70261740)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 応力腐食割れ / 破壊 / ミクロ組織 / 量子ビーム / 応力 / インコネル / 低合金鋼 / 中性子回折

Outline of Final Research Achievements

Stress Corrosion Cracking (SCC) was studied using 3D characterization methods for a weld component made of Inconel and low alloy steel (LAS) and an austenitic stainless steel. Macro- to micro-scopic residual stress measurements and creviced bent beam SCC tests were performed for Inconel/LAS samples. The possible reasons for the suppression of SCC crack propagation near the weld interface found at a nuclear power plant were estimated to include the crack branching at the grain boundary (GB) parallel to the interface, i.e., Type II GB, compressive residual stresses in the LAS region and crack tip oxidation in the LAS at the interface.
SCC crack propagation behavior in CT specimens of sensitized SUS304 steel was observed three-dimensionally using a serial sectioning technique. Crack branching and stress/plastic strain distribution were influenced by stress intensity factor, corrosion environment and microstructure particularly character of grain boundary and delta ferrite grains.

Free Research Field

材料強度学