Numerical Study on Laser Cladding Process of Magnesium Alloys

2011 ◽  
Vol 214 ◽  
pp. 224-229 ◽  
Author(s):  
Qing Ming Chang ◽  
Chang Jun Chen ◽  
Xia Chen ◽  
Si Qian Bao
Keyword(s):  
Temperature Dependence ◽  
Magnesium Alloys ◽  
Laser Cladding ◽  
Process Parameters ◽  
Numerical Study ◽  
Metal Flow ◽  
Three Dimensional ◽  
Scanning Speed ◽  
Beam Diameter ◽  
Melt Pool

In this paper, a three-dimensional simulation model for laser-cladding processes of magnesium alloys is proposed. The applied loading is a moving heat source that depends on process parameters such as power density, laser beam diameter and scanning speed. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. In these parameters, Marangoni force is the most important in affecting the molten metal flow and the contour of the melt pool. Both the length and depth of the melt pool vary sharply with temperature dependence of surface tension when the absolute value of this temperature dependence is at lower value.

Modeling on Laser Cladding on In718 Superalloy

2011 ◽  
Vol 80-81 ◽  
pp. 46-50
Author(s):  
Qing Ming Chang ◽  
Chang Jun Chen ◽  
Xia Chen ◽  
Si Qian Bao ◽  
Chen Gang Pan
Keyword(s):  
Laser Cladding ◽  
Process Parameters ◽  
Scanning Speed ◽  
Beam Diameter ◽  
Numerical Resolution ◽  
Applied Loading ◽  
Melt Pool ◽  
Laser Cladding Process ◽  
In718 Superalloy ◽  
Complex Boundary

A 3-D modeling based on the numerical resolution of fluid flow and heat transfer for laser-cladding processes of In718 Superalloy is proposed. The implementation of developed procedures allowed us to treat the problem with specific and complex boundary conditions. The applied loading is a moving heat source that depends on process parameters such as power density, laser beam diameter and scanning speed. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. The computational results present good coincidences with the corresponding experiments of laser cladding process.

A parametric study of a blown powder laser cladding and alloying process using a two-dimensional conduction model

2004 ◽  
Vol 218 (7) ◽  
pp. 703-709 ◽  
Author(s):  
S Kumar ◽  
S Roy
Keyword(s):  
Laser Cladding ◽  
Process Parameters ◽  
Power Level ◽  
Scanning Speed ◽  
Two Dimensional ◽  
Surface Geometry ◽  
Conduction Model ◽  
Laser Parameters ◽  
Melt Pool ◽  
Blown Powder

A two-dimensional model has been developed to predict the temperature field and melt pool shape during blown powder laser cladding. A finite volume method has been used to solve the two-dimensional energy equation for a body moving relative to a stationary laser heat source. A boundary fitted coordinate system has been employed as the built-up surface geometry is complex. Important dimensionless groups representing laser parameters power ( P) and scanning speed ( U) and the process parameters built-up height and average dilution are identified. The effect of laser parameters on process parameters is investigated. For cladding P/U should always be kept low (less than 1) to reduce the average dilution, and in order to achieve the desired clad height the power level P should be controlled.

Numerical Study on Laser Cladding of BT20 Alloy

2012 ◽  
Vol 479-481 ◽  
pp. 850-853
Author(s):  
Qing Ming Chang ◽  
Jing Yuan ◽  
Yin Kai Yang ◽  
Xia Chen ◽  
Chang Jun Chen ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Laser Cladding ◽  
Molten Pool ◽  
Numerical Study ◽  
Scanning Speed ◽  
Work Piece ◽  
Numerical Resolution ◽  
Incident Laser Power ◽  
Melt Pool ◽  
Thermal Phenomena

A 3-D modeling based on the numerical resolution of fluid flow and heat transfer are utilized to investigate the thermal phenomena during laser laser-cladding processes of BT20 alloy. From this model, it has been found that the shape and size of the molten pool in the work piece are affected by laser cladding parameters such as scanning speed and the incident laser power. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. Furthermore, it has been observed that the surface tension temperature coefficient, Marangoni convection, which is sensitive to the active elements in the titanium alloy composition, also affect the pattern of the fluid flow in the molten pool.

Experimental Study of Forming Rene95 Alloy Parts by Laser Cladding

2001 ◽  
Author(s):  
Qilin Deng ◽  
Dejin Hu ◽  
Jingyu Pei ◽  
Wenwu Zhang ◽  
Y. Lawrence Yao
Keyword(s):  
Experimental Study ◽  
Laser Cladding ◽  
Laser Power ◽  
Alloy Powder ◽  
High Strength ◽  
Scanning Speed ◽  
Main Process ◽  
Beam Diameter ◽  
Laser Beam Diameter ◽  
Metal Parts

Abstract In this paper, experimental study of forming metal parts by laser cladding Rene95 alloy powder was reported. The influence of main process parameters, such as laser power, scanning speed and laser beam diameter, on the thickness, width and the angle of the laser cladding track was investigated. The microstructures of laser cladding parts were studied and compared with those of common casting parts. The obtained Rene95 metal parts formed by laser cladding are dense and of high strength.

scholarly journals Effect of Process Parameters and Material Properties on Laser Micromachining of Microchannels

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 123 ◽  
Author(s):  
Matthew Benton ◽  
Mohammad Hossan ◽  
Prashanth Konari ◽  
Sanjeewa Gamagedara
Keyword(s):  
Process Parameters ◽  
Laser System ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Scanning Speed ◽  
Transient Heat Conduction ◽  
Laser Micromachining ◽  
Rapid Phase ◽  
Widespread Application ◽  
Optimization Of Process Parameters

Laser micromachining has emerged as a promising technique for mass production of microfluidic devices. However, control and optimization of process parameters, and design of substrate materials are still ongoing challenges for the widespread application of laser micromachining. This article reports a systematic study on the effect of laser system parameters and thermo-physical properties of substrate materials on laser micromachining. Three dimensional transient heat conduction equation with a Gaussian laser heat source was solved using finite element based Multiphysics software COMSOL 5.2a. Large heat convection coefficients were used to consider the rapid phase transition of the material during the laser treatment. The depth of the laser cut was measured by removing material at a pre-set temperature. The grid independent analysis was performed for ensuring the accuracy of the model. The results show that laser power and scanning speed have a strong effect on the channel depth, while the level of focus of the laser beam contributes in determining both the depth and width of the channel. Higher thermal conductivity results deeper in cuts, in contrast the higher specific heat produces shallower channels for a given condition. These findings can help in designing and optimizing process parameters for laser micromachining of microfluidic devices.

Research on Optimization of Laser Cladding Process Parameters Based on Orthogonal Experimental Method

2020 ◽  
Vol 866 ◽  
pp. 72-81
Author(s):  
Da Shu ◽  
Si Chao Dai ◽  
Ji Chao Sun ◽  
Feng Tao ◽  
Ping Xiao ◽  
...  
Keyword(s):  
Dilution Rate ◽  
Laser Cladding ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Scanning Speed ◽  
Optimum Level ◽  
Scoring Method ◽  
Laser Cladding Process ◽  
Potential Applications ◽  
Orthogonal Experiment Method

The orthogonal experiment method is used in optimal design of laser cladding, such as laser power (P), scanning speed (SS), powder feeding rate (PFR) and shielding gas velocity (SGV) etc. Both the dilution rate and the aspect ratio are investigated by comprehensive scoring method, which transforms multi-index into single index. In view of the nonlinear characteristics of laser cladding process parameters, the optimum level of each factor based on interaction effect is obtained by analyzing binary tables. Finally, the relationship between the laser cladding process parameters and the two indexes (the dilution rate and the ratio of width to height of coating) is obtained. This method has potential applications for the further investigating on the laser cladding process rules.

scholarly journals Influence of Melt-Pool Stability in 3D Printing of NdFeB Magnets on Density and Magnetic Properties

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 139 ◽  
Author(s):  
Mateusz Skalon ◽  
Michael Görtler ◽  
Benjamin Meier ◽  
Siegfried Arneitz ◽  
Nikolaus Urban ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Layer Thickness ◽  
Process Parameters ◽  
Permanent Magnets ◽  
Scanning Speed ◽  
Maximum Energy ◽  
Powder Layer ◽  
Influence Of Process Parameters ◽  
Layer Height ◽  
Melt Pool

The current work presents the results of an investigation focused on the influence of process parameters on the melt-track stability and its consequence to the sample density printed out of NdFeB powder. Commercially available powder of Nd7.5Pr0.7Fe75.4Co2.5B8.8Zr2.6Ti2.5 alloy was investigated at the angle of application in selective laser melting of permanent magnets. Using single track printing the stability of the melt pool was investigated under changing process parameters. The influence of changing laser power, scanning speed, and powder layer thickness on density, porosity structure, microstructure, phase composition, and magnetic properties were investigated. The results showed that energy density coupled with powder layer thickness plays a crucial role in melt-track stability. It was possible to manufacture magnets of both high relative density and high magnetic properties. Magnetization tests showed a significant correlation between the shape of the demagnetization curve and the layer height. While small layer heights are beneficial for sufficient magnetic properties, the remaining main parameters tend to affect the magnetic properties less. A quasi-linear correlation between the layer height and the magnetic properties remanence (Jr), coercivity (HcJ) and maximum energy product ((BH)max) was found.

scholarly journals Multi-objective numerical simulation of geometrical characteristics of laser cladding of cobalt-based alloy based on response surface methodology

2020 ◽  
pp. 002029402094495
Author(s):  
Lu-jun Cui ◽  
Meng Zhang ◽  
Shi-Rui Guo ◽  
Yan-Long Cao ◽  
Wen-Han Zeng ◽  
...  
Keyword(s):  
Prediction Model ◽  
Response Surface ◽  
Laser Cladding ◽  
Process Parameters ◽  
Laser Power ◽  
Influence Factors ◽  
Scanning Speed ◽  
Laser Cladding Remanufacturing ◽  
Main Influence

The objectives of this study are to optimize the key process parameters of laser cladding remanufacturing parts, improve the sealing quality of the hemispherical valve and prolong and improve its service life and reliability. A high-power fiber-coupled semiconductor laser was used to fabricate a single Co-based alloy cladding layer on the pump valve material ZG45 plate. The key process parameters of laser power, scanning speed and powder feeding rate in the process of laser remanufacturing are taken as optimization variables, and the coating width, coating height, coating depth, aspect ratio and dilution rate are taken as response indexes. Based on the response surface analysis method, the central compound experiment is designed using Design-Expert software. The variance analysis of the experimental results is performed, and the regression prediction model of the process parameters relative to the corresponding index is established. Through analysis of the established perturbation diagram and three-dimensional response surface, it is concluded that the main influence factors of melting width and penetration depth are laser power and positive effect, and the main influence factors of melting height are scanning speed and negative effect. The average error of each regression prediction model is lower than 10%. The above research work has important guiding significance for optimizing the process parameters and improving the cladding quality of cobalt-based alloy on ZG45.

scholarly journals Modelling the Marangoni convection in laser heat treatment

2004 ◽  
Vol 120 ◽  
pp. 299-306
Author(s):  
J.-M. Drezet ◽  
S. Pellerin ◽  
C. Bezençon ◽  
S. Mokadem
Keyword(s):  
Single Crystal ◽  
Marangoni Convection ◽  
Three Dimensional ◽  
Marangoni Effect ◽  
Scanning Speed ◽  
Liquid Pool ◽  
Beam Diameter ◽  
Finite Element Software ◽  
Melting Pool ◽  
Columnar To Equiaxed Transition

Epitaxial Laser Metal Forming (E-LMF) consists in impinging a jet of metallic powder onto a molten pool formed by controlled laser heating and thereby, generating epitaxially a single crystal deposit onto the damaged component. This new technique aims to be used for the repair and reshape single crystal gas turbine components. Because of the very localised melting pool, the high temperature gradients produced during the process must be carefully controlled in order to avoid both the columnar-to-equiaxed transition (CET) and the appearance of hot tears. To this end, heat flow modelling is required to establish the relationship between process parameters such as laser power, beam diameter and scanning speed, and the local solidification conditions. When modelling the heat transfer within the sample, it is necessary to include the liquid flow pattern generated by the surface tension driven convection known as the Marangoni effect. Indeed, the fluid flow in the liquid pool dictates the shape of the traces as shown by the measurements carried out at EPF-Lausanne in re-melting experiments. A three dimensional (3D) model is implemented in the finite element software calcosoft$^\text{\textregistered}$ in order to model the development of the fluid convection within the liquid pool. It is shown that the velocities due to natural convection are of the order of 1 mm/sec whereas Marangoni convection produces velocities of the order of 1 m/sec. Moreover, at low scanning speeds, the liquid pool becomes larger than the beam diameter and the development of Marangoni eddies leads to a widening and deepening of the pool. The local solidification conditions such as the thermal gradient and the solidification speed can be extracted at both the solidus and liquidus temperatures to assess the risk of CET and hot cracking.

scholarly journals Optimization of Process Parameters, Microstructure, and Properties of Laser Cladding Fe-Based Alloy on 42CrMo Steel Roller

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2061 ◽  
Author(s):  
Jiang Ju ◽  
Yang Zhou ◽  
Maodong Kang ◽  
Jun Wang
Keyword(s):  
Laser Cladding ◽  
Process Parameters ◽  
Laser Power ◽  
Salt Spray ◽  
Continuous Casting Machine ◽  
Scanning Speed ◽  
Optimum Process ◽  
Chemical Compositions ◽  
Cladding Layer ◽  
42Crmo Steel

The mould foot roller is a key component of a continuous casting machine. In order to investigate the possibility of using laser cladding to repair mould foot roller, Fe-based powders and 42CrMo steel are used in this work. The laser cladding process parameters were optimized by orthogonal experiments. The chemical compositions, microstructure, properties of the cladding layer under the optimum process parameters, and substrate were systematically investigated by using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness test, wear test, and salt spray corrosion test. The results indicate that the primary factor affecting the width and depth of the cladding layer is laser power. The scanning speed also has a significant effect on the height of the cladding layer. The optimum process parameters for repairing the mould foot roller are 2 kW laser power, 4 mm/s scanning speed, and 15 g/min feeding rate of powder. Along the depth direction of the cladding layer, the microstructure of the coating gradually transforms from plane crystal, cell grains, or dendrites to equiaxed grains. The matrix is mainly martensite with retained austenite; the eutectic phase is composed of netlike M2B, particulate M23(C,B)6, and M7(C,B)3 phase. The hardness of the cladding layer is significantly improved, about three times that of the substrate. The weight loss of the cladding layer is just half that of the substrate. Its wear resistance and corrosion resistance have been significantly improved. The work period of the laser cladding-repaired foot roller is much longer than for the surfacing welding-repaired one. In summary, laser cladding technology can increase the life of mould foot rollers.

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