Analysis of the regimes in the scanner-based laser hardening process

Martı́nez, Silvia; Lamíkiz, Aitzol; Ukar, Eneko; Calleja, A.; Arrizubieta, J.A.; Lacalle, Luis Norberto López de

doi:10.1016/j.optlaseng.2016.10.005

Cited by 78 publications

(40 citation statements)

References 19 publications

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“…Elastic waves are generated due to the thermal expansion. Based on the power density of the irradiating pulse laser, there are two thermal models for the generation of ultrasonic waves, namely, ablation generation and thermo-elastic generation [23]. For the latter, the power density of the laser pulse is lower than the ablation threshold of the irradiated material, which indicates non-destructive wave generation.…”

Section: Generation and Modulation Of Laser-generated Ultrasonicsmentioning

confidence: 99%

Detection and Quantification of Damage in Metallic Structures by Laser-Generated Ultrasonics

2018

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Abstract:The appearance of damage on metallic structures is inevitable due to complex working environments. Non-destructive testing (NDT) of these structures is critical to the safe operation of the equipment. This paper presents a non-destructive damage detection, visualization, and quantification technique based on laser-generated ultrasonics. The undamaged and damaged metallic structures are irradiated with laser pulses to produce broadband input ultrasonic waves. Damage to the structures plays the role of a nonlinear radiation source of new frequencies. Usually these new frequencies are too weak to be detected directly. Here, the state space predictive model is proposed to address the problem. Based on the recorded responses in the time domain, the state space attractors are reconstructed. Damage to the structures is shown to change the properties of the attractors. A nonlinear damage detection feature called normalized nonlinear prediction error (NNPE) is extracted from the state space to identify the changes in the attractors-and hence the damage. Furthermore, the damage is visualized and quantified using the NNPE values extracted from the entire area by using a laser scanning technique. Experimental results validate that the proposed technique is capable of detecting, visualizing and quantifying artificial damage to aluminum alloy plates and actual fatigue cracks to a twin-screw compressor body.

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Section: Generation and Modulation Of Laser-generated Ultrasonicsmentioning

confidence: 99%

Detection and Quantification of Damage in Metallic Structures by Laser-Generated Ultrasonics

2018

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“…It can be concluded that although heat treatment improved the hardness in the FZ, it did not change the properties of the base metal. Work done by various researchers on Laser hardening, [19] has shown that the most relevant parameter in the hardened layer depth is the scanning speed, followed by the hardened track width. Another group of researchers have given a good account of modelling such processes by modelling the Added Layers by Coaxial Laser Cladding [20].…”

Section: Vickers Hardness Testmentioning

confidence: 99%

An Experimental Evaluation of Electron Beam Welded Thixoformed 7075 Aluminum Alloy Plate Material

Chegeni

Kapranos

2017

Metals

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Two plates of thixoformed 7075 aluminum alloy were joined using Electron Beam Welding (EBW). A post-welding-heat treatment (PWHT) was performed within the semi-solid temperature range of this alloy at three temperatures, 610, 617 and 628 • C, for 3 min. The microstructural evolution and mechanical properties of EB welded plates, as well as the heat-treated specimens, were investigated in the Base Metal (BM), Heat Affected Zone (HAZ), and Fusion Zone (FZ), using optical microscopy, Scanning Electron Microscopy (SEM), EDX (Energy Dispersive X-ray Analysis), and Vickers hardness test. Results indicated that after EBW, the grain size substantially decreased from 67 µm in both BM and HAZ to 7 µm in the FZ, and a hardness increment was observed in the FZ as compared to the BM and HAZ. Furthermore, the PWHT led to grain coarsening throughout the material, along with a further increase in hardness in the FZ.

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“…Among the many precision machining methods, magnetic abrasive finishing (MAF) is undoubtedly proven to be an effective precision processing method [1][2][3][4]. Though the MAF process, as a kind of ultra-precision machining method, can achieve nanoscale surface finishing, the polishing efficiency decreases when a hard metal surface is polished by the MAF process, as compared to other processing methods [5][6][7]. Thereby, diamond is usually used to polish hard metal surfaces in the MAF process in order to ensure the polishing efficiency.…”

Section: Introductionmentioning

confidence: 99%

Study on Electrolytic Magnetic Abrasive Finishing for Finishing Stainless Steel SUS304 Plane with a Special Compound Machining Tool

Sun

Zou

2018

JMMP

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Abstract:In order to improve the finishing efficiency of traditional plane magnetic abrasive finishing (MAF), we have previously proposed an effective plane MAF process combined with an electrolytic process and developed a special compound machining tool for the electrolytic magnetic abrasive finishing (EMAF). In this research, the EMAF process is divided into two finishing steps. The first finishing step is the EMAF step, and a single MAF step constitutes the second finishing step. The machinability of SUS304 material can be improved through the formation of passive films from the electrolytic process in the EMAF step. Meanwhile, the passive films can be rapidly and easily removed by friction between the magnetic particles and the workpiece-generated mechanical machining force. Thus, the surface finishing efficiency can be greatly improved. Compared with a dedicated MAF machining tool or a dedicated electrolytic machining tool, this special compound machining tool can synchronously achieve MAF and electrolytic processes to make the processing more convenient. This study focuses on exploring mechanical finishing characteristics of the special compound machining tool through MAF experiments. Additionally, EMAF experiments are conducted under the optimal mechanical finishing conditions. The experimental results of the EMAF process show that the surface roughness R a can be reduced to less than 30 nm at the 4-min EMAF step, and it can be further reduced to 20 nm at the 10-min MAF step.

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Analysis of the regimes in the scanner-based laser hardening process

Cited by 78 publications

References 19 publications

Detection and Quantification of Damage in Metallic Structures by Laser-Generated Ultrasonics

Detection and Quantification of Damage in Metallic Structures by Laser-Generated Ultrasonics

An Experimental Evaluation of Electron Beam Welded Thixoformed 7075 Aluminum Alloy Plate Material

Study on Electrolytic Magnetic Abrasive Finishing for Finishing Stainless Steel SUS304 Plane with a Special Compound Machining Tool

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