Lopez, Ana Beatriz
(IDMEC, Instituto Superior Tecnico, Universidade de Lisboa)
,
Assuncao, Eurico
(IDMEC, Instituto Superior Tecnico, Universidade de Lisboa)
,
Quintino, Luisa
(IDMEC, Instituto Superior Tecnico, Universidade de Lisboa)
,
Blackburn, Jonathan
(TWI Ltd.)
,
Khan, Ali
(TWI Ltd.)
For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this st...
For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this study aims to improve the reliability of laser cutting for such work and indicates guidelines to optimize the cutting procedure, in particular, nozzle combinations (standoff distance and focus position), to minimize waste material. The results obtained show the performance levels that can be reached with 10 kW fiber lasers, using which it is possible to obtain narrower kerfs than those found in published results obtained with other lasers. Nonetheless, fiber lasers appear to show the same effects as those of $CO_2$ and ND:YAG lasers. Thus, the main factor that affects the kerf width is the focal position, which means that minimum laser spot diameters are advised for smaller kerf widths.
For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this study aims to improve the reliability of laser cutting for such work and indicates guidelines to optimize the cutting procedure, in particular, nozzle combinations (standoff distance and focus position), to minimize waste material. The results obtained show the performance levels that can be reached with 10 kW fiber lasers, using which it is possible to obtain narrower kerfs than those found in published results obtained with other lasers. Nonetheless, fiber lasers appear to show the same effects as those of $CO_2$ and ND:YAG lasers. Thus, the main factor that affects the kerf width is the focal position, which means that minimum laser spot diameters are advised for smaller kerf widths.
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가설 설정
To minimize detrimental effects, the procedures were characterized as follows: (1) The cut depth is not significantly influenced by different nozzle combinations. (2) The factor that appears to affect the kerf width most significantly is the focal position. Minimum laser spot diameters are thus advised for smaller kerf widths.
Minimum laser spot diameters are thus advised for smaller kerf widths. (3) The same thickness can be cut by decreasing the beam diameter. However, after a certain interaction time, the beam diameter does not influence the kerf width.
However, after a certain interaction time, the beam diameter does not influence the kerf width. (4) For constant laser power and cutting speed, focusing the laser beam below the surface of the material results in less material removal for the same interaction time.
제안 방법
After cutting, specimens were prepared from transverse sections; the surfaces were prepared for metallographic inspection by “cold mounting” and polishing to display cross-sectional images of the kerfs.
The experiments involved fixing the laser power and assist gas pressure, and varying the SD and focus position (FP). Measurements were performed with a 10 kW power source and 8 bar gas pressure, for cutting carbone-manganese steel bars with thickness up to 70 mm.
High-power fiber laser is a promising cutting tool for decommissioning of nuclear reactors. The objective of this experimental study was to assess the performance of a 10 kW laser for thick sections. To minimize detrimental effects, the procedures were characterized as follows: (1) The cut depth is not significantly influenced by different nozzle combinations.
The trials involved moving of the laser beam from one side of the sample to the other, at a constant speed, in order to discover how deep it can cut, in a single pass, for each speed. After cutting, the kerf width and cut depth produced were measured.
The sequence of cutting speeds was as follows: 1,000 mm/min, 800 mm/min, 600 mm/min, 400 mm/min, 200 mm/min, 100 mm/ min, and 50 mm/min. Then, six more cuts were made and an analysis was undertaken, for comparison purposes, with plate thicknesses of 6 mm, 12 mm, and 40 mm, covering the range of thicknesses used in the nuclear sector. The cutting speeds used were 1,200 mm/min, 1,500 mm/min, and 200 mm/min.
대상 데이터
An IPGYLR-10000 fiber laser operating at maximum power was used for the trials. The delivery system consisted of a fiber with a diameter of 200 mm. In the cutting head, the optics consisted of a 120 mm collimator and five lenses of different focal lengths (starting from 250 mm).
The material tested was S355 CeMn steel, widely used in the nuclear sector. Two different experiments were undertaken: for the first experiments, bars of 70 mm thickness were considered suitable, since much deeper cuts are not expected in the nuclear sector.
Using spacer rings, the nozzles were arranged to produce different combinations of SDs and FPs, and to promote different behaviors of the assist gas. Without defocusing the laser beam, seven parameter sets were tested, all with the same nozzle exit design. Fig.
참고문헌 (13)
C. Chagnot, G. De Dinechin, G. Canneau, Cutting performances with new industrial continuous wave ND: YAG high power lasers: for dismantling of former nuclear workshops, the performances of recently introduced high power continuous wave ND: YAG lasers are assessed, Nucl. Eng. Des. 240 (2010) 2604-2613.
G. Verhaeghe, P. Hilton, The Effect of Spot Size and Laser Beam Quality on Welding Performance When Using High-power Continuous Wave Solid-state Lasers, ICALEO, 2005.
B.S. Yilbas, Laser cutting of thick sheet metals: Effects of cutting parameters on kerf size variations, J. Mater. Process. Technol. 201 (2008) 285-290.
L. Quintino, A. Costa, R. Miranda, D. Yapp, V. Kumar, C.J. Kong, Welding with high power fiber lasers-a preliminary study, Mater. Des. 28 (2007) 1231-1237.
P.A. Hilton, A. Khan, R. Buckingham, Advances in Laser Cutting as a Decommissioning and Dismantling Tool Laser Cutting of Plate Material, TWI internal report. (2015) 1-6.
M. Hashemzadeh, W. Suder, S. Williams, J. Powell, A.F.H. Kaplan, K.T. Voisey, The application of specific point energy analysis to laser cutting with 1 ${\mu}m$ laser radiation, 8th International Conference on Photonic Technologies, LANE, 2014, Physics Procedia 56 (2014) 909-918.
H.A. Eltawahni, M. Hagino, K.Y. Benyounis, T. Inoue, A.G. Olabi, Effect of $CO_2$ laser cutting process parameters on edge quality and operating cost of AISI316L, Opt. Laser Technol. 44 (2012) 1068-1082.
P.A. Molian, Dual-beam $CO_2$ laser cutting of thick metallic materials, J. Mater. Sci. 28 (1933) 1738-1748.
R. Pfeifer, D. Herzog, M. Hustedt, S. Barcikowski, Pulsed Nd :YAG laser cutting of NiTi shape memory alloys-influence of process parameters, J. Mater. Process. Technol. 210 (2010) 1918-1925.
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