• 마이크로전자및패키징학회지
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• 제24권3호
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• pp.53-56
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• 2017

Laser cladding is a technique for forming beads by melt-sintering with a laser while directly feeding metal powder onto the base material through nozzles. This technique, which is applied in laser surface treatment technology, is useful for repairing broken or worn parts by allowing selective formation of the surface layer of the base metal material. In this paper, laser cladding process was performed on STS316L powder using high power continuous wave laser with IR wavelength and the cladding characteristics according to process conditions were experimentally analyzed.

• Journal of Welding and Joining
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• 제18권3호
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• pp.83-88
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• 2000

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 Nd:YAG laser cladding with wire feeding on the mechanical properties of Inconel alloy were investigated. inconel alloy is used as the material of nuclear steam generator tubing because of its mechanical properties and corrosion resistance properties. The device for Nd:YAG laser cladding with wire feeding was designed. It consists of the wire feeding system, the wire cladding system and the shielding gas system which prevents the clad layer from being oxidized. Experimental as results indicated that the wire feeding direction and position were important for laser cladding with wire feeding. The wire 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. The hardness of clad layer and heat affected zone increased with increasing of cladding speed.

• 한국기계가공학회지
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• 제18권11호
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• pp.35-40
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• 2019

Laser processing has been used in various fields. In this study, the feasibility of a hydrophobic surface was investigated through the laser cladding technique. A diode laser was used, and the output was set to 600-800 W. Seven different specimens were prepared with different cladding widths and spacings, and the contact angles for water droplets were evaluated. As a result, the contact angle of water droplets measured in the direction parallel to the cladding line was higher than that in the vertical direction. The wider the cladding width and the cladding space, the higher the contact angle in the parallel direction. It is thought that when a higher contact angle is formed in the parallel direction, more air can be placed in the valley between the cladding lines. In addition, for the hydrophobic coating effect, the contact angle of the coated cladding surface was increased by about $5-15^{\circ}$ as a whole compared to the coated smooth surface. It was confirmed that the wetting characteristics were improved through the cladding.

• Journal of Welding and Joining
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• 제19권5호
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• pp.481-485
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal. The effect of $CO_2$ laser cladding with high viscosity mixed powders was investigated. High viscosity mixed powder consists of bronze powder and flux that is used at a high temperature condition. The mixed powder has a high viscosity that it can be easily pasted over a curved or slope substrate. The device for mixed powder was designed and manufactured. It consists of the high viscosity mixed powder feeding system, the preheating system and the shielding gas system which prevents the clad layer from being oxidized. The results of experiment indicated that the feed rate of high viscosity mixed powder was important for later cladding with mixed powder feeding. The high viscosity mixed powder and substrate must be preheated to prevent porosity from breaking at the clad layer. The experimental result shows that the high viscosity mixed can be applied for laser cladding process.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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• pp.256-259
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• 2000

High viscosity mixing powder is a very useful material for laser cladding. This material has a high viscosity so that it can be sticked to substrate. Therefore, Laser cladding can be performed on a curved or slope surface. Laser cladding can be easily performed with the material instead of wire that is difficult to be manufactured in some case. In this experiment, it was used a high viscosity mixing powder which consists of a high temperature flux and a bronze powder. And AC2B alloy material was used as a substrate. Flux prevents the clad layer from being oxidized and increases bonding property between substrate and cladding material. It makes possible to laser cladding at low level energy.

• 한국생산제조학회지
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• 제26권3호
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• pp.337-343
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• 2017

The laser cladding process on structural steel (SCM440) and gray cast iron (GC250) substrates with Co-based powder (Stellite 12) was studied. A diode laser (2 kW) was used as a heat source, and the powder was supplied by a disc rotary powder feeder. The relationship between the laser cladding process and the cross-sectional analysis of coating was examined based on coating shape and microstructure. Additionally, the microhardness was measured to confirm the mechanical property improvements. As a result, proper laser cladding conditions were selected through this study and verified by cross-sectional analysis. In addition, the evaluation process for laser cladding feasibility was conducted on the selected materials.

• 한국재료학회지
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• 제31권11호
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• pp.601-607
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• 2021

Laser cladding a surface treatment process that grants superior characteristics such as toughness, hardness, and corrosion resistance to the surface, and rebuilds cracked molds; as such, it can be a strong tool to prolong service life of mold steel. Furthermore, compared with the other similar coating processes - thermal spray, etc., laser cladding provides superior bonding strength and precision coating on a local area. In this study, surface characteristics are studied after laser cladding of low carbon steel using 18%Cr-2.5%Ni-Fe powder (Rockit404), known for its high hardness and excellent corrosion resistance. A diode laser with wavelength of 900-1070 nm is adopted as laser source under argon atmosphere; electrical power for the laser cladding process is 5, 6, and 10 kW. Fundamental surface characteristics such as crossectional microstructure and hardness profile are observed and measured, and special evaluation, such as a soldering test with molten ALDC12 alloy, is conducted to investigate the corrosion resistance characteristics. As a result of the die-soldering test by immersion of low carbon alloy steel in ALDC12 molten metal, the clad layer's soldering thickness decreases.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.196-198
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• 2007

Laser cladding technology was studied as a method for upgrading the present repair procedures of damaged tubes in a nuclear steam generator and Doosan subsequently developed and designed a new Laser Cladding Repair System. One of the important features of this newly developed Laser Cladding Repair System is that molten metal can be deposited on damaged tube surfaces using a laser beam and filler wire without the need to install sleeves inside the tube. Laser cladding qualification tests on the steam generator tube material, Alloy 600, were performed according to ASME Section IX.

• 한국압력기기공학회 논문집
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• 제11권1호
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• pp.53-60
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• 2015

This study was investigated to develop process technology of laser cladding with austenite stainless steel for Weld Inlay repair of dissimilar metal weld in reactor vessel in/outlet nozzles. Weld Inlay experiments were performed by laser cladding repair system consisting of common manipulator, laser apparatus and welding process scheduler, etc. Single pass welding experiments were conducted in order to obtain the optimum welding process parameters for filler wires of ER309L and Alloy 52M before multi-layer laser cladding. Based on the above obtained results, multi-layer laser cladding experiments were carried out, and welding qualities for weld specimens were estimated by PT, OM, SEM and EDS analysis. Consequently, it was revealed that multi-layer laser cladding on austenite stainless steel using filler wires of ER309L and Alloy 52M could be possible to meet ASME Code standard without any weld defect.

• 한국정밀공학회지
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• 제28권7호
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• pp.783-788
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• 2011

The recent development of bio-ceramic material is being studied in various bio-material engineering field. There are lots of technical difficulties because manufacturing or bonding technique are required bio-friendliness, cleanliness and persistence. Zirconia ceramic powder is cladded on Ti-6AI-4V metallurgically by laser cladding processing. Laser cladding system with powder feeding delivery is designed and manufactured for optimum processing condition. Increasing of manufacturing speed and good quality of clad layer are achieved by application of preheating of substrate before laser cladding. The thin dilution and good clad layer on the substrate are obtained for applications of bio-materials such as the dental materials and the articulated joints of human body.