Effects of powder feeding rate on interaction between laser beam and powder streamin laser cladding process

2004 ◽  
Vol 19 (4) ◽  
pp. 69-72 ◽  
Author(s):  
Huang Yan-lu ◽  
Li Jian-guo ◽  
Liang Gong-ying ◽  
Su Jun-yi
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Feeding Rate ◽  
Laser Cladding Process ◽  
Powder Feeding

Numerical Simulation on Temperature Field in Multi-Layers Inside-Beam Powder Feeding when Laser Cladding

2012 ◽  
Vol 499 ◽  
pp. 114-119 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
X.B. Liu ◽  
Cheng Fa Song ◽  
Li Ning Sun
Keyword(s):  
Numerical Simulation ◽  
Heat Source ◽  
Laser Beam ◽  
Cooling Rate ◽  
Light Source ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Initial Conditions ◽  
Cladding Layer ◽  
Powder Feeding

Numerical simulation of laser cladding is the main research topics for many universities and academes, but all researchers used the Gaussian laser light source. Due to using inside-beam powder feeding for laser cladding, the laser is dispersed by the cone-shaped mirror, and then be focused by the annular mirror, the laser can be assumed as the light source of uniform intensity.In this paper,the temperature of powder during landing selected as the initial conditions, and adopting the life-and-death unit method, the moving point heat source and the uniform heat source are realized. In the thickness direction, using the small melt layer stacking method, a finite element model has been established, and layer unit is acted layer by layer, then a virtual reality laser cladding manu-facturing process is simulated. Calculated results show that the surface temperature of the cladding layer depends on the laser scanning speed, powder feed rate, defocus distance. As cladding layers increases, due to the heat conduction into the base too late, bath temperature will gradually increase. The highest temperature is not at the laser beam, but at the later point of the laser beam. In the clad-ding process, the temperature cooling rate of the cladding layer in high temperature section is great, and in the low-temperature, cooling rate is relatively small. These conclusions are also similar with the normal laser cladding. Finally, some experiments validate the simulation results. The trends of simulating temperature are fit to the actual temperature, and the temperature gradient can also ex-plain the actual shape of cross-section.

scholarly journals Optimization of laser cladding process for additive repair of high temperature and high pressure valve sealing surface

2019 ◽  
Author(s):  
Lei Che
Keyword(s):  
High Pressure ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Laser Cladding ◽  
Laser Power ◽  
Feeding Rate ◽  
Scanning Speed ◽  
Alloy Layer ◽  
Laser Cladding Process ◽  
Valve Sealing

Laser cladding technology is highly suitable for the remanufacturing of thin-walled and easily deformable parts due to its concentrated energy density. Due to the high temperature and high pressure corrosion environment, the valve sealing surface is prone to corrosion, wear and other failures. A nickel-based tungsten carbide alloy layer was prepared on the valve sealing surface substrate material by laser cladding process. By designing orthogonal experiments, the effects of laser power (P), scanning speed (Vb), powder feeding rate (Vf), and WC content (wt%) on the alloy layer were investigated. A fuzzy comprehensive evaluation method including macroscopic quality, microstructure, microhardness, anti-wear performance, oxidation resistance, compactness and corrosion resistance was proposed. The experimental results showed that the hardness, oxidation resistance and corrosion resistance of the laser alloy layer are significantly improved compared with the matrix; the optimum process parameters and the addition ratio of WC powder are laser power (P) of 1.1 kW and scanning speed (Vb) of 800 mm/min. The powder feeding rate (Vf) was 20%, and the WC content was 20% by weight.

Evaluation of the Stability and Precision of Powder Delivery during Laser Additive Manufacturing

2013 ◽  
Vol 380-384 ◽  
pp. 4348-4352
Author(s):  
Kai Zhang ◽  
Lei Wang ◽  
Xiao Feng Shang
Keyword(s):  
Laser Beam ◽  
Molten Pool ◽  
Gas Flow ◽  
Feeding Rate ◽  
Shielding Gas ◽  
Metal Parts ◽  
Deposited Metal ◽  
Computer Aided ◽  
The Stability ◽  
Powder Feeding

The fabrication of metal parts is the backbone of the modern manufacturing industry. Laser forming is combination of five common technologies: lasers, rapid prototyping (RP), computer-aided design (CAD), computer-aided manufacturing (CAM), and powder metallurgy. The resulting process creates part by focusing an industrial laser beam on the surface of processing work piece to create a molten pool of metal. A small stream of powdered alloy is then injected into the molten pool to build up the part gradually. By moving the laser beam back and forth and tracing out a pattern determined by a CAD, the solid metal part is fabricated line by line, one layer at a time. By this method, a material having a very fine microstructure due to rapid solidification process can be produced. In the present work, a type of direct laser deposition process, called Laser Metal Deposition Shaping (LMDS), has been employed and developed to fabricate metal parts. In the LMDS process, the powder delivery system is an important component to perform the powder transport from powder storage box to powder nozzle, which supplies the raw material for the as-deposited metal parts. Consequently, the stability and precision of powder delivery during LMDS is essential to achieve the metal parts with high quality, so it is critical to evaluate the main factors closely related to the stability and precision of powder delivery. The shielding gas flow and the powder feeding rate were ascertained through experimental measure and formula calculation. The results prove that the suitable shielding gas flow and powder feeding rate can promote the stability and precision of powder delivery, which is the basis for the fabrication of as-deposited metal parts with flying colors.

Laser Cladding Forming of Cantilevered Thin-Walled Part Based on Hollow-Laser Beam Inside Powder Feeding Technology2

2015 ◽  
Vol 42 (10) ◽  
pp. 1003003
Author(s):  
石拓 Shi Tuo ◽  
王伊卿 Wang Yiqing ◽  
卢秉恒 Lu Bingheng ◽  
石世宏 Shi Shihong ◽  
陆斌 Lu Bing ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Thin Walled ◽  
Hollow Laser Beam ◽  
Powder Feeding

Effect of laser beam incidence angle on cladding morphology in laser cladding process

2020 ◽  
Vol 34 (4) ◽  
pp. 1531-1537
Author(s):  
Guan Zhang ◽  
Wenlei Sun ◽  
Dongmei Zhao ◽  
Pengfei Fan ◽  
Feng Guo ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Incidence Angle ◽  
Laser Cladding Process ◽  
Beam Incidence

scholarly journals Microstructure and Mechanical Properties of the ((CoCrFeNi)95Nb5)100−xMox High-Entropy Alloy Coating Fabricated under Different Laser Power

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1477
Author(s):  
Wenrui Wang ◽  
Qi Sun ◽  
Dingzhi Wang ◽  
Junsong Hou ◽  
Wu Qi ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Volume Fraction ◽  
Beam Power ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Laser Cladding Process ◽  
Laser Beam Power ◽  
Interdendritic Phase ◽  
Dendritic Structures

In this paper, the ((CoCrFeNi)95Nb5)100−xMox (x = 1, 1.5 and 2) high-entropy alloy (HEA) coatings were fabricated on the substrate of 45# steel by laser cladding process under different laser beam power. The influence of laser beam power and molybdenum element content on the microstructure and microhardness of the HEA coatings was investigated. Results show that the HEA coatings were composed of face-centered cubic (FCC) phase and Laves phase, had low porosity, and bonded well to the substrate. The Mo1 coating is composed of cellular dendritic structures and columnar dendritic structures. With the increase of molybdenum element content, the columnar dendritic structures disappeared, the grains are refined, and the arrangement of grains is more compact. The volume fraction of the interdendritic phase under the laser beam power of 800 W was small and irregular. After the laser beam power was increased to 1000 W, the volume fraction of the interdendritic phase was increased. Under the laser beam power of 1200 W, the volume fraction of the interdendritic phase was small again. Therefore, the coatings fabricated under the laser beam power of 1000 W had a larger volume fraction of the interdendritic phase and higher microhardness. With the increase in molybdenum content, the grain changed from columnar dendrite to cellular dendrite, and the microhardness of the coating increased. The characteristics of the laser cladding process, the formation of Laves phase, and the fine grain strengthening lead to high microhardness of the coatings.

Effect of Defocus Distance on Layer Quality in Insider-Laser Coaxial Powder Feeding Laser Cladding

2011 ◽  
Vol 287-290 ◽  
pp. 2419-2422
Author(s):  
Hou Shun Sun ◽  
Shi Hong Shi ◽  
Ge Yan Fu ◽  
Jia Zhang ◽  
Chen Wang ◽  
...  
Keyword(s):  
Surface Quality ◽  
Laser Cladding ◽  
Process Parameters ◽  
High Ratio ◽  
Metal Part ◽  
Laser Cladding Process ◽  
Surface Flatness ◽  
Powder Feeding

Insider-laser coaxial powder feeding laser cladding is one kind of technique, which can be used in metal part directly manufacturing field. Compared with outsider-laser coaxial powder feeding laser cladding techniques, it has significant advantages [1]. In order to research the effect of defocus distance on the layer quality in insider-laser coaxial powder feeding laser cladding, it has taken some expriments in this paper to study the layer quality by constantly changing the defocus distance, with other laser cladding process parameters invariable. In addition, this paper measues, analysis the cladding layer’s width, height, the surface quality (including surface flatness, flat-wide ratio and flat-high ratio [2]), hardness and microstructure, then summarizes the effect of the defocus distance on the layer quality in this paper.

A Method of Crack Control in Laser Cladding Process with Changing Power Density Distribution of Laser Beam

2011 ◽  
Vol 38 (1) ◽  
pp. 0103004 ◽  
Author(s):  
王东生 Wang Dongsheng ◽  
田宗军 Tian Zongjun ◽  
王泾文 Wang Jingwen ◽  
段宗银 Duan Zongyin ◽  
沈理达 Shen Lida ◽  
...  
Keyword(s):  
Laser Beam ◽  
Density Distribution ◽  
Power Density ◽  
Laser Cladding ◽  
Crack Control ◽  
Power Density Distribution ◽  
Laser Cladding Process

Laser cladding forming of fan-shaped part based on hollow laser beam inside powder feeding technology

2017 ◽  
Vol 46 (9) ◽  
pp. 906007 ◽  
Author(s):  
周 斌 Zhou Bin ◽  
石世宏 Shi Shihong ◽  
邓志强 Deng Zhiqiang ◽  
石 拓 Shi Tuo ◽  
傅戈雁 Fu Geyan ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Shaped Part ◽  
Hollow Laser Beam ◽  
Feeding Technology ◽  
Powder Feeding
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