# Fileset

[M_HAYAKAWA_NIMS Award Symposium 2023.pdf](https://mdr.nims.go.jp/filesets/e141e580-d4f0-4aff-8e9e-a9ab4834cf81/download)

## Creator

[Masao HAYAKAWA](https://orcid.org/0000-0001-5143-8350)

## Rights

[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

## Other metadata

[Review of Damage Evaluation and Remanufacturing for Material Sustainability](https://mdr.nims.go.jp/datasets/ea1fb64f-b7e6-4d35-beba-cd757bd041e2)

## Fulltext

PowerPoint プレゼンテーションReview of Damage Evaluation and Remanufacturing for Material SustainabilityMasao HAYAKAWAResearch Center for Structural Materials, NIMSThe development of functional recovery technology for surface treatments is crucial for remanufacturing. Laser hardeningto allow the repair of friction-fatigue damage in used carburized martensite steel gears. In addition, prior austenite grainrefinement and restoration of the retained austenite phase in the laser hardening quenched layer were realized for thefriction-fatigued specimen.Product remanufacturing offers a path to achieving the United Nation's sustainable development goals. In the rapidly expandingconstruction-machinery industry, remanufacturing can reduce environmental load and maintenance costs. Although hydrauliccomponents and engines are often remanufactured, carburized parts, such as large gear parts and the bearings in reducers ortransmission systems, are frequently scrapped. Reusing these expensive parts would significantly increase their value; however, doing soentails the development of techniques for non-destructive testing and functional recovery.2μm(a) New gear2μm(b) Used gear0.00.20.40.60.81.01.21.41.E+04 1.E+05 1.E+06 1.E+07Retained austenite rate  (After/Before testing), γRNumber of cycles, N6,000N3,000N1,000N1×104                        1×105                             1×106                          1×107The rate of change in the retained austenite phase and residual stress measured byX-ray diffraction (XRD), appears to be proportional to microcracking in the surfacelayer. The rate of change in both the retained austenite phase and in residual stresscan therefore be used as a safe-side criterion for determining reusability.Nondestructive measurements of the gear parts using XRD (μ-X360s ; cosα method)Laser hardening (LH) スライド番号 1