• Proceedings of the KWS Conference
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• 2001.10a
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• pp.128-131
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal, resulting in low total heat input. The effects of $CO_2$ laser cladding with powder feeding on mechanical properties of VERSAlloy were studied. Their low melting point (under 1093$^{\circ}C$) enables overlays to be applied with minimum dilution and base metal distortion. Experiment results indicated that powder feeding speed and quantity were important for laser cladding with powder feeding. The powder feeding speed should be adapted according to cladding speed for good shaping of clad layer. The effect of heat on the HAZ size can be limited and the growth of grain size of HAZ size was not serious.

• Journal of Welding and Joining
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• v.35 no.2
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• pp.58-62
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• 2017

A319 aluminum alloy containing 6.5% Si and 3.5% Cu as major alloying elements has been widely used in machinery parts because of its excellent castability and crack resistance. However it needs more wear resistance to extend its usage to the severe wear environments. It has been known that hyper-eutectic Al-Si alloy having more than 12.6% Si contains pro-eutectic Si particles, which give better wear resistance and lubrication characteristics than hypo-eutectic Al-Si alloy like A319 alloy. In this study, it was tried to clad hyper-eutectic Al-Si alloy on the surface of A319 alloy. In the experiments, Al-36%Si alloy powder was mixed with organic binder to make a fluidic paste. The paste was screen-printed on the A319 alloy surface, melted by pulsed Nd:YAG laser and alloyed with the A319 base alloy. As experimental parameters, the average laser power was changed to 111 W, 202 W and 280 W. With increasing the average laser power, the melting depth was changed to $142{\mu}m$, $205{\mu}m$ and $245{\mu}m$, and the dilution rate to 67.2 %, 72.4 % and 75.7 %, and the Si content in the cladding layer to 16.2 %, 14.6 % and 13.7 %, respectively. The cross-section of the cladding layer showed very fine eutectic microstructure even though it was hyper-eutectic Al-Si alloy. This seems to be due to the rapid solidification of the melted spot by single laser pulse. The average hardness for the three cladding layers was HV175, which was much higher than HV96 of A319 base alloy. From the block-on-roll wear tests, A319 alloy had a wear loss of 5.8 mg, but the three cladding layers had an average wear loss of 3.5 mg, which meant that an increase of 40 % in wear resistance was obtained by laser cladding.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.432-442
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• 2023

Characterizing the behavior of nuclear reactor plate fuels is vital to the progression of advanced fuel systems. The states of pre- and post-irradiation plates need to be determined effectively and efficiently prior to and following irradiation. Due to the hostile post-irradiation environment, characterization must be completed remotely. Laser-based characterization techniques enable the ability to make robust measurements inside a hot-cell environment. The Laser Shock (LS) technique generates high energy shockwaves that propagate through the plate and mechanically characterizes cladding-cladding interfaces. During an irradiation campaign, two Idaho National Laboratory (INL) fabricated MP-1 plates had a fuel breach in the cladding-cladding interface and trace amounts of fission products were released. The objective of this report is to characterize the cladding-cladding interface strengths in three plates fabricated using different fabrication processes. The goal is to assess the risk in irradiating future developmental and production fuel plates. Prior LS testing has shown weaker and more variability in bond strengths within INL MP-1 reference plates than in commercially produced vendor plates. Three fuel plates fabricated with different fabrication processes will be used to bound the bond strength threshold for plate irradiation insertion and assess the confidence of this threshold value.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.633-634
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• 2006

• Journal of Welding and Joining
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• v.31 no.1
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• pp.11-20
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• 2013

Recent developing tendency of overlay welding on welding methods are studied by searching of NDSL, ScienceDirect and KIPRIS. PTA, Laser cladding, SMAW, GTAW, GMAW, SAW and ESW are selected as welding methods. Development and improvement of various new overlay welding processes and technology are introduced, especially PTA and Laser cladding in abroad overlay welding technology are activated substantially.

• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.177-187
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• 2000

Dilution is an important factor which influences the properties of clad layer. In this paper the change of dilution during laser cladding and the control of dilution are simulated by a finite element method. The adaptive mesh method is adopted for the time-dependent finite element method computation so that the shape of melt pool can be well represented. The situation of the width control of melt pool is also simulated, which indicates that the dilution can be controlled if the width of melt pool is controlled. Computational results indicate that if a line energy (input energy per unit distance) remains constant the dilution will increase with time, especially at the beginning. Simulation results show that it is possible to control dilution in a certain range if the line energy decreases with time. Experiment of Nd: YAG laser cladding with wire feeding is performed. Experiment results coincide well with the FEM results.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.796-801
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• 2002

Corrosion and tensile properties of zircaloy-4 cladding tube having a laser welding part in elevated temperature are studied to present the criterion of quality evaluation in nuclear reactor and find the scientific basis of SCC, with laser welding method using by coupling up cladding tube to end cap. In the result of tensile test($400^{\circ}C$), the fracture is not happened in the welding part but base metal and the result of corrosion test($400^{\circ}C$ 1500psi steam), corrosion rate of the molten zone and PMZ is a little higher than the other zone.

• Laser Solutions
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• v.2 no.2
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• pp.34-41
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• 1999

A RS840 $CO_2$laser and a powder auto-feeding apparatus have been used to deposit single tracks of Ni-base superalloy on low carbon steel. In this paper, the effects of laser cladding parameters on clad geometry, dilution and microhardness are studied. As a results, the w/h ratio of the clad layer increases with decreasing powder feed rate and increasing laser scan speed. Increase of powder density and decrease of specific energy have little effect on dilution. It was found that the clad layer of the highest hardness has a structure in which fine and leaf like phases are dispersed in ${\gamma}$Ni matrix.

• Laser Solutions
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• v.3 no.1
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• pp.38-45
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• 2000

A 4㎾ RS840 CO2 laser with a powder auto-feeding apparatus has been used to deposit multiple overlapping tracks of Ni-base superalloy on to low carbon steel. It was found that the surface roughness(turbulence) of an overlapped cladding layer decreased with the increase of the overlapping ratio in an oscillating manner. When the overlapping ratio had values of 0.62, the surface turbulence was lowest. Overlapping ratio offer significant potential for improvement of materials surface properties such as corrosion performance and wear resistance. This paper reports that the overlapping ratio shows best corrosion resistance. The tensile residual stresses generated at the higher overlapping ratio( ＞ 0.45) and the element concentration of Fe increased in the surface layer at the lower overlapping ratio( ＜ 0.45) may lead to worse corrosion resistance.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.72-72
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• 2002

Corrosion and tensile properties of zircaloy-4 cladding tube having a laser welding part in elevated temperature are studied to present the criterion of quality evaluation in nuclear reactor and find the scientific basis of SCC, with laser welding method using by coupling up cladding tube to end cap. In the result of tensile test(400℃), the fracture is not happened in the welding part but base metal and the result of corrosion test(400℃ 1500psi steam), corrosion rate of the molten zone and PMZ is a little higher than the other zone.