- 标题
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Advanced Coating Materials || Investigations on Laser Surface Modification of Commercially Pure Titanium Using Continuous-Wave Nd:YAG Laser
摘要： Laser transformation hardening, a type of laser heat treatment technique, has advantages over the traditional hardening techniques, which include high precision, automation control with the choices of optimum desired minimum hardened depth of 241 microns (0.241 mm) for low laser beam power: 750 Watts have been achieved in this research work. In the present study, the laser transformation hardening of commercially pure titanium sheet material of thickness being 1.6 mm is investigated using CW (continuous-wave) 1.6-kW solid-state Nd:YAG laser. Commercially pure titanium has widespread application in various fields of industries including the medical, nuclear, automobile, and aerospace. A full factorial design (FFD) with Response Surface Methodology (RSM) is employed to establish, optimize, and investigate the relationships of three laser transformation hardening process parameters such as laser power, scanning speed, and focused position on laser hardened bead profile parameters such as hardened bead width, hardened depth, angle of entry of hardened bead profile, heat input, and power density. RSM is used to develop pseudo-closed-form models from the computational parametric studies. Effects of laser process parameters: laser power, scanning speed, and focal point position on laser hardened bead geometries such as hardened bead width, hardened depth, an angle of entry of hardened bead profile, heat input, and power density were carried out using RSM. Results indicate that the scanning speed and laser power have the significant effect as compared to the focal point position on the laser hardening process parameters. The scanning speed has a positive effect on all responses while the laser power has a positive effect particularly on hardened bead width and angle of entry of hardened bead profile as compared to hardened depth and heat input. The optimum laser hardening conditions are identified sequentially to minimize hardened depth, an angle of entry of hardened profile, heat input, power density, and maximum hardened bead width. The validation results demonstrate that the developed models are accurate with low percentages of errors observed.
关键词： bead geometry,full factorial design,response surface methodology,analysis of variance,Laser transformation hardening
更新于2025-09-19 17:15:36
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Optimization of welding parameters in laser welding of Ti6Al4V using VIKOR optimization method
摘要： Ti6Al4V alloys are widely preferred in the biomedical industries owing to its higher corrosion resistance in human body environment. Welding plays a critical role in the manufacture of complicated biomedical components. Hence, the necessity to identify suitable joining process for joining Ti6Al4V is very important. In this work, an attempt is made to study the CO2 laser welding of titanium sheets (Ti6Al4V) having dimensions of 100 (cid:1) 60 (cid:1) 3 mm. Laser welding was done based on L9 Taguchi array with welding speed (v), laser power(P), and shielding gas ?ow rate(f) as input parameters. The weld quality was analysed by measuring the depth of penetration (DOP), bead width (BW), and hardness values. Full penetration was observed only in two welding trials. The optimized parameters were identi?ed by using the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) multi-objective optimization technique. Analytic Hierarchy Process (AHP) is used for determining the weights of the relative importance of the output factors. VIKOR method identi?ed that the 7th experimental run (power = 1.3 kW, speed = 0.3 m/min, shielding gas ?ow rate = 20 L/min) as the optimized parameter for getting the weld with full depth of penetration, lesser bead width, higher microhardness values in the fusion zone (FZ) and heat affected zone (HAZ). The metallurgical characterization of the optimized weld is also dicussed with the aid of microstructures taken from Scanning Electron Microscope (SEM).
关键词： CO2 laser welding,Hardness values,Bead geometry,VIKOR multi-objective optimization technique,Ti6Al4V
更新于2025-09-19 17:13:59
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Welding characteristics of butt-welded Inconel625 plate using CO2 laser beam
摘要： Inconel weldments are widely used in automobile and structural industries. In this study, the joints of Inconel625 are made with CO2 Laser beam welding process. The experimentation is carried out with two sets of process parameters varying the laser power and estimating the response of the welded component. Radiography analysis and distortion in the weldments are carried out. Distortion is measured using the Vernier height gauge. The lower the better-quality characteristics are chosen for distortion. The welds are free from flaws and the lower heat input results in the lower distortion.
关键词： Radiography,Distortion,Laser beam welding,Inconel625,Bead geometry
更新于2025-09-19 17:13:59
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Optimization of Process Parameters Using Surface Response Methodology for Laser Welding of Titanium Alloy
摘要： Laser beam welding input conditions are greatly influence the quality of the welded joints and they have significant role on the controlling of their strength and metallurgical properties. The metallurgical properties and weld bead geometry and mechanical properties of the joints determine the quality of the joints. In this study, the fusion zone width, penetration, width of the heat affected zone and strength of the titanium alloy welds were investigated using laser welding process. The surface response methodology design is carried out for the experimental design by the development of regression equations. Analysis of variance (ANOVA) was used to check the validity of the model. In order to identify the significant parameters, student’s test is conducted. The obtained results from response surface methodology were compared with the experimental results and validated.
关键词： Optimization,Fusion zone,Mechanical properties,Laser welding,Welding parameters,Titanium alloy,Bead geometry
更新于2025-09-16 10:30:52
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Parameter Optimization for Laser Welding of High Strength Dissimilar Materials
摘要： Dissimilar joining of high strength tensile steels are joined using laser beam welding. The selection of the welding conditions for joining of dissimilar materials is highly required to satisfy the quality of the joints. In the present investigation, optimization technique were used to determine the optimal welding conditions. Initially welding conditions were optimized for weld geometry and formation of different zones in the weldment. The metallurgical and mechanical properties of the welds are greatly influenced by the geometry of the welds. The surface response methodology design is carried out for the experimental design by the development of regression equations. Analysis of variance (ANOVA) was used to check the validity of the model. The output of the welding conditions were compared with the predicted values to identify the accuracy of the model. The obtained results from response surface methodology were compared with the experimental results and validated.
关键词： Optimization,Fusion zone,Mechanical properties,Laser welding,Welding parameters,High strength steel,Bead geometry
更新于2025-09-16 10:30:52
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Effect of Process Parameters and Heat Input on Weld Bead Geometry of Laser Welded Titanium Ti-6Al-4V Alloy
摘要： Laser beam welding is one of the most favorable welding technique and its importance in industry is demanding due to higher welding speeds and lower dimensions and distortions in the welds. Moreover, its high strength to weld geometries and minimal heat affected zones makes favorable for various industrial applications. In the present study, laser welding of titanium alloy was investigated to observe the effects of parameters on the bead geometry and metallurgical properties. The laser power and welding speeds were varied to identify their impact on the formation of weld geometry. The width and depth of the fusion zone is varied with welding conditions. The finer grains identified in weld zone and the width of heat affected zone was significantly changes with laser welding power. The mechanical properties of the weld joint are controlled by obtaining optimum weld bead geometry and width of the head affected zone in the welds.
关键词： Heat input,Fusion zone,Microstructure,Mechanical properties,Laser welding,Microhardness,Weld bead geometry,Titanium alloy
更新于2025-09-16 10:30:52
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A convolutional neural network approach on bead geometry estimation for a laser cladding system
摘要： Laser cladding is a complex manufacturing process. As the laser beam melts the feedstock powder, small changes in laser power or traverse speed reflect on deviations of the deposition’s geometry. Thus, fine-tuning these process parameters is crucial to achieve desirable results. In order to monitor and further understand the laser cladding process, an automated method for clad bead final geometry estimation is proposed. To do so, six different convolutional neural network architectures were developed to analyze the process’ molten pool image acquired by a 50-fps coaxial camera. Those networks receive both the camera image and the process parameters as inputs, yielding width and height of the clad beads as outputs. The results of the network’s performances show testing error mean values as little as 8 μm for clad beads around a millimeter in height. For the width dimension, in 95% of the cases, the error remained under 15% of the bead’s width. Plots of the target versus the estimated values show coefficients of determination over 0.95 on the testing set. The architectures are then compared, and their performances are discussed. Deeper convolutional layers far exceeded the performance of shallower ones; nonetheless, deeper densely connected layers decreased the performances of the networks when compared with shallower ones. Those results represent yet another alternative on intelligent process monitoring with potential for real-time usage, taking the researches one step further into developing a closed-loop control for this process.
关键词： Optical monitoring,Geometry estimation,Laser cladding,Convolutional neural network,Bead geometry
更新于2025-09-12 10:27:22
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Temperature Profile, Bead Geometry, and Elemental Evaporation in Laser Powder Bed Fusion Additive Manufacturing Process
摘要： Powder bed fusion processes have been a focus of research in recent years. Computational models of this process have been extensively investigated. In most cases, the distribution of heat intensity over the powder bed during the laser–powder interaction is assumed to follow a Gaussian beam pattern. However, the heat distribution over the surface is a complicated process that depends on several factors such as beam quality factor, laser wavelength, etc. and must be considered to present the laser–material interaction in a way that represents the actual beam. This work presents a process in which a non-Gaussian laser beam model is used to model the temperature pro?le, bead geometry, and elemental evaporation in the powder bed process. The results are compared against those of a Gaussian beam model and also an experiment using Inconel 718 alloy. The model offers good predictions of the temperature, bead shape, and concentration of alloying elements.
关键词： Additive manufacturing,Temperature profile,Powder bed fusion,Laser powder bed fusion,Bead geometry,Non-Gaussian beam,Elemental evaporation
更新于2025-09-11 14:15:04
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Accurate prediction model of bead geometry in crimping butt of the laser brazing using generalized regression neural network
摘要： There are few researches that concentrate on the prediction of the bead geometry for laser brazing with crimping butt. This paper addressed the accurate prediction of the bead profile by developing a generalized regression neural network (GRNN) algorithm. Firstly GRNN model was developed and trained to decrease the prediction error that may be influenced by the sample size. Then the prediction accuracy was demonstrated by comparing with other articles and back propagation artificial neural network (BPNN) algorithm. Eventually the reliability and stability of GRNN model were discussed from the points of average relative error (ARE), mean square error (MSE) and root mean square error (RMSE), while the maximum ARE and MSE were 6.94% and 0.0303 that were clearly less than those (14.28% and 0.0832) predicted by BPNN. Obviously, it was proved that the prediction accuracy was improved at least 2 times, and the stability was also increased much more.
关键词： bead geometry,generalized regression neural network,prediction model,laser brazing
更新于2025-09-11 14:15:04