Ryuichiro Ebara

Ultrasonic Corrosion Fatigue Behaviorof Duplex Stainless Steel

Ultrasonic Corrosion Fatigue Tests were Conducted for SUS329J3L in Air and 3%NaCl Aqueous Solution. Reduction of Giga-Cycle Corrosion Fatigue Strength was 12.5%. Corrosion Pit was Observed on Corrosion Fatigue Crack Initiation Area. Striation was Predominantly Observed on Crack Propagation Area both in Air and 3% Nacl Aqueous Solution. it can be Concluded that the Reduction of Corrosion Fatigue Strength of SUS329J3L is due to the Corrosion Pit Formation at Corrosion Fatigue Crack Initiation Area.

Analysis on Critical CTOD of Long-Term Used Penstock

Many studies have been conducted to characterize the fracture toughness of structural steels and their welded joints. However, most studies focus on newly developed steels, and the number of studies on the fracture toughness of long-term used steels in structural components is rather limited. Furthermore, a lack of data on the fracture toughness causes difficulties in evaluating the structural integrity of existing steel structures. In this study, CTOD tests were performed to characterize the fracture toughness of penstock that has been in service for 50 years. By measuring the critical crack tip opening displacement in conjunction with analysis for chemical compositions, the characteristics of fracture toughness were investigated.

The role of microfractography in failure analysis of machine components and structures

Microfractography is an indispensable key technology in failure analysis of machine components and structures. In this chapter, the development of microfractography in failure analysis is briefly described. The emphasis is focused upon the application of microfractography in corrosion fatigue failure of compressor drive steam turbine blade and cargo oil tank in a very large crude oil carrier. The important role of stretched zone in unstable fracture is highlighted in failure analysis of hot and cold forging die for automotive components. Finally, recommended studies in microfractography in failure analysis are touched on briefly.

Nitriding Effect on Corrosion Fatigue Strength of Low Alloy Steel in 1% HCl Aqueous Solution

In this paper the emphasis is focused upon nitriding effect on corrosion fatigue strength of Cr-Mo low alloy steel in 1% HCl aqueous solution.Corrosion fatigue strength enhancement of Cr-Mo low alloy steel by nitriding is discussed on the basis of the corrosion fatigue testing results on gas and ion nitrided Cr-Mo low alloy steel plate specimen with 3.5mm thickness in 1%HCl aqueous solution. It can be concluded that residual compressive stress distributed on the nitrided specimen surface caused improvement of corrosion fatigue strength of Cr-Mo low alloy steel.