New Etching Method for Revealing Prior Austenite Grain Boundaries

Enomoto, M.; Sam, Hong Song; Yamada, Kazuo; Shimizu, Masao; Kunio, Takeshi

doi:10.1299/kikai1938.40.407

Cited by 6 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They were etched in 3 vol.-% nitric acidzethanol solution for the grain structure observation, and in 1?25 vol.-% picric acidziron(III) chloride hexahydrate aqueous solution for 240 s at ambient temperature to find previous austenite grain boundary. 16 The microstructure was observed by optical and scanning electron microscopy (SEM). Electron probe microanalyser (EPMA) was employed in order to analyse distribution of the chemical composition in the weld.…”

Section: Methodsmentioning

confidence: 99%

Effect of contamination on microstructure in friction stir spot welded DP590 steel

Ohashi

Fujimoto

Mironov³

et al. 2009

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

In this study, FSSW of DP590 steel was performed using both bare and TiC/TiN coated Si 3 N 4 tool with Ar shielding, and effect of contamination on the microstructure during FSSW was examined. Defect free welds were successfully obtained at all welding conditions. Si, N and O contaminations were clearly found in the weld when bare Si 3 N 4 tool was used without Ar shielding, but the coated tool and Ar shielding could suppress the contaminations. The contaminations caused higher hardness in the vicinity of the pin hole and reduced the weld strength. The present study showed that the prevention of the contaminations could improve the weld strength, especially the cross-tension strength, in FSSW of DP590 steel using Si 3 N 4 tool.

show abstract

Section: Methodsmentioning

confidence: 99%

Effect of contamination on microstructure in friction stir spot welded DP590 steel

Ohashi

Fujimoto

Mironov³

et al. 2009

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

show abstract

The early stage of fatigue crack growth in martensitic steel

et al. 1981

View full text Add to dashboard Cite

In low ductility and high strength steels, the early stage fatigue behavior associated with non-metallic inclusions is a highly localized phenomenon near the inclusions. However, the nature of the fatigue crack initiation process is not clear. In this paper, a special emphasis is placed on the possible differences in the mechanism of initiation and the early growth of fatigue cracks between a martensitic steel and ordinary ductile materials.The poor adhesion between matrix and aluminum oxide inclusion leads to the formation of an inclusion pit which serves as a simple stress raiser. The fatigue crack originates at the periphery of this inclusion pit at an angle of 45 degrees to the principal stress direction. Metallurgical and micro-fractographical observations revealed that the initiation and early growth of fatigue cracks from non-metallic inclusion are of the shear rather than the tensile mode. Thus, it is concluded that, though the fatigue process is quite localized in the vicinity of inclusion, the mechanism for an initiation and early growth of fatigue cracks is essentially the same as that for ductile materials. The effects of metallurgical heterogeneities in the martensite, such as the prior austenite grain boundaries, packets, and plates on the initiation and early growth of the cracks, are also discussed from the mechanical-metallurgical viewpoint.

show abstract