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A numerical investigation of similar and dissimilar clad materials on H13 steel substrate in the Laser Cladding process
摘要： Minimal dilution, controlled heat input, excellent metallurgical bonding between the clad and the substrate material made the laser cladding process more appealing compared to other conventional surface modification techniques. However, generated residual stress in the finished component encounters this process for applications. In this work, a thermo-mechanical model has been developed numerically using ANSYS’18 multi-physics platform to analyse and compare residual stresses among different cladding materials. Three different clad materials, H13 steel, Al2O3 and TiC were used on the same H13 tool steel substrate. Tensile residual stresses were observed in the clad, at interface and in substrate near the interface for all samples in X direction. It was found that Al2O3 coating on H13 steel produced lower residual stress (1220 MPa) in the clad than TiC coating on H13 steel (1359 MPa) due to lower mismatch of thermal strain. This proposed analysis offers to select the combination of clad and substrate materials having minimum residual stresses in the Laser Cladding process.
关键词： residual stresses,Laser cladding process,thermal history,materials
更新于2025-09-12 10:27:22
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[IEEE 2019 25th International Conference on Automation and Computing (ICAC) - Lancaster, United Kingdom (2019.9.5-2019.9.7)] 2019 25th International Conference on Automation and Computing (ICAC) - Temperature Field Simulation and Experimental Analysis of Laser Cladding 45 Steel
摘要： In order to explore the influence in temperature field change on the cladding quality and substrate deformation during laser cladding, adopt the APDL parametrization design language in ANSYS finite element analysis software to establish the laser cladding process model and the cladding process. The dynamic simulation and the temperature field distribution during the simulation cooling process were carried out, and the experimental verification and comparison were carried out under the same process parameters. The results showed that the single-pass cladding layer has the best shape under the process parameters that laser power of 1800w, powder feeding capacity of 20g/min and scanning speed of 8mm/s. During the cladding simulation process, the temperature of the molten pool and the peak temperature of the time-course curve are basically constant, and the temperature field distribution takes on a steady-state distribution. After the cladding,the temperature of cladding layer diffuses to the both ends, the temperature field changes gradually decrease during the cooling process, and the temperature is in an unsteady state. As the cooling time increases, the temperature drop gradient gradually decreases. The temperature field cooling analysis is carried out under the same process parameters. The error between the experimental results and the simulation results is less than 10%, which is very consistent and has guiding significance for practical experiments.
关键词： temperature field,finite element analysis,laser cladding
更新于2025-09-12 10:27:22
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Analysis of a Ni-Fe-Cr-Mo-Si hardfacing alloy manufactured by laser cladding: influence of the iron content on the wear resistance properties
摘要： In this article, we present an ongoing study on a Ni-Fe-Cr-Mo-Si based alloy, as one of the potential cobalt free hardfacing materials. Here, we analyze the effect of the variation of iron content on microstructure and wear property that is induced by a controlled dilution the 316L substrate, or by direct addition. First, we present the state of the art on the proposed Ni-Cr-Mo-Si based alloy. Then, the laser cladding setup is presented and the process parameter map search of the Ni-Fe-Cr-Mo-Si based alloy too. Then, iron is added to the base Ni-Cr-Mo-Si alloy by direct fusion of the powders coming from two different powder feeders and directly blended into the coaxial nozzle used. Finally the samples are analyzed in iron content, microhardness and microstructure. The tribology tests of the samples exhibit a clear change in wear behavior with the iron content and an improvement at a certain level of iron.
关键词： Tribology,Nickel Base Alloys,Laser Cladding,Hardfacing Materials,Nuclear Energy,Wear resistance
更新于2025-09-12 10:27:22
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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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Laser cladded Ti + TiB2 on Steel Rail Microstructural Effect
摘要： Rail transportation has been one of the most efficient and sustainable means of mobility with large economic value. The rail wheel flange steers on the rail track for motion with imparts of frictional force and rotational speed. High temperature is generated and prolific wear at high speed which is reduced by lubrication. Additive manufacturing techniques of laser cladding of steel rail surface were employed in this study with the ceramics of Titanium and Titanium boride powders at different mix ratio on steel rail surface. Different metallurgical characterization of cladded surface was carried out. The best hardness and microstructural view were noticed at 50:50 mix ratio of the cladded ceramics. The phase transformation of the varying mix ratio was also revealed.
关键词： Microstructure,Wheel flanges,Wear,Laser Cladding,Steel Rail
更新于2025-09-12 10:27:22
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Local heat treatment of a laser build-up
摘要： Laser cladding or laser metal deposition involves the deposition of any weldable material onto the surface of a metal substrate by means of a laser beam. Although clad deposits are fully fusion-joined to the substrate material, the very low heat-input associated with laser cladding results in extremely low dilution as well as relatively small heat-affected zones (HAZ). Subsequent to the clad-repair process, heat treatment is normally not necessary, but some critical components may require it due to the high hardness obtained in the HAZ. Conventional heat treatments are most often time-consuming, costly and could cause possible distortion of the component. In this study local laser heat treatment of the HAZ after laser cladding has been investigated on different substrate materials (21CrMoV5-11, X22CrMoV12-1, 34CrNiMo6) as an alternative to full post-weld heat treatment (PWHT). Due to the focused heat of the laser beam, the required time at temperature for heat treatment was only a fraction compared to that of conventional heat treatments. It was observed that the HAZ hardness could indeed be lowered significantly by controlling the temperature and interaction time of the local treatment. For 21CrMoV5-11 the HAZ hardness was decreased to below 400 HV with most treatments at 800 °C, but the 8 s interaction time was found to be optimal. The X22CrMoV12-1 material showed the highest resistance to PWHT and only the longest interaction time at 800 °C resulted in HAZ hardness close to 400 HV. The largest decrease in HAZ hardness was obtained with the 34CrNiMo6 material and the longest interaction time at 700 °C resulted in the lowest hardness.
关键词： heat-affected-zone,hardness,local heat treatment,Laser,cladding
更新于2025-09-12 10:27:22
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Near-Net Shaping Control of Triangular Stacking in Laser Cladding Process
摘要： Fabrication of complex parts with irregular geometric cross-section can be realized through precise control of triangular stacking in laser cladding process. This paper deals with the optimization of overlapping ratio and scanning strategy in order to obtain near-net shaping parts. First, multi-track overlapping surface formation mechanisms and surface flatness evaluation method are described. Then, the effects of overlapping ratio and scanning strategy on surface flatness are investigated and optimized. Afterwards, the formation of triangular stack under the optimized parameters are evaluated in terms of accuracy and metallographic aspects. The results show that the minimum flatness occurred when the overlapping ratio is about 20 %. Changing the scanning sequence from left-to-right to center-to-sides can help reduce the negative effects caused by the accumulated heat during the material deposition process, thereby improving the performance efficiency of the cladding.
关键词： Overlapping,Shaping Control,Triangular Stacking,Laser Cladding,Surface flatness
更新于2025-09-12 10:27:22
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Non-dimensional process maps for normalized dilution limits in laser direct metal deposition
摘要： The quality and integrity of laser direct metal deposition (DMD) processes primarily depend on the substrate dilution and the nature of residual stresses in the deposited layer. An adequate amount of melting of the substrate is required to ensure the formation of sound metallurgical bond between the deposited layer and substrate. Insufficient melting and excessive dilution may lead to adverse effects. Furthermore, the dilution also controls the location of the melt front in substrate where maximum tensile residual stresses occur. The presence of tensile residual stresses in the deposited layer may be detrimental to service life, especially, for components repaired using DMD. These challenges can be overcome by predicting and controlling the dilution and the nature of residual stress as a function of process parameters. To model the direct metal deposition process, a 3D coupled metallo-thermomechanical finite element model is employed to predict the temperature and the residual stress due to thermomechanical interactions and metallurgical transformations and the substrate dilution. Non-dimensional process parameters affecting the dilution in laser DMD have been identified using Buckingham-Π theorem. The metallo-thermomechanical model is used to develop empirical relationships via regression to correlate the dimensionless process parameters with the dilution. These correlations are employed in developing the isopleths in the form of process maps, which could predict regions of inadequate fusion and excessive dilution (unduly large substrate melting). It may be noted that the limiting value of dilution corresponds to the condition where the entire deposited layer (cladding) is under compressive residual stresses. Any dilution higher than this will result in excess substrate melting which is undesirable. The limiting values of normalized dilution are estimated to be 1 and ~1.3 corresponding to complete deposit-substrate fusion and presence of entirely compressive residual stress in deposition, respectively. These process maps are designed to provide a theoretical framework for understanding the influence of process parameters and provide informed decisions on the selection of appropriate process parameters for ensuring the quality and integrity of the deposition.
关键词： Laser cladding,residual stress,metallo-thermomechanical finite element model,process maps,dilution,non-dimensional parameters
更新于2025-09-12 10:27:22
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Laser cladding in-situ nano-submicron TiC reinforced ultrafine- grained Fe-based composite layers on 42CrMo steel
摘要： In-situ nano-submicron TiC reinforced ultrafine-grained Fe-based cladding layers were prepared by laser cladding gradient particle sizes of ferrotitanium, graphite, and iron powder on the surface of 42CrMo steel. Microstructures and corrosion resistance were analyzed using X-ray diffraction, scanning electron microscope, and an electrochemical workstation. Results showed that the average particle size of the in-situ TiC was 0.25 μm, and ranged from 0.04 μm to 1.10 μm, with 11.0 % being on the nano scale. The microstructure of the cladding layer was lath martensite, and the average grain size of the cladding layer matrix was 4.08 μm, reaching the ultrafine-grained scale. The average hardness of the cladding layer was approximately 720 HV0.2, which was 425 HV0.2 higher than that of the 42CrMo steel. The corrosion current density of the cladding layer was more than two times lower than that of the 42CrMo steel.
关键词： nano-submicron,ultrafine-grained,TiC,laser cladding
更新于2025-09-12 10:27:22
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Wear Tribo-Performances of Laser Cladding Colmonoy-6 and Stellite-6 Micron Layers on Stainless Steel 304 Using Yb:YAG Disk Laser
摘要： Stainless steel material has been widely used in aeronautical, chemical and nuclear industries due to good corrosion resistance. However, the material has less hardness and wear resistance. In this study, two various depositions namely Colmonoy-6 and Stellite-6 have produced on 304 Stainless steel. Besides, the coating was examined to reveal their metallurgical, mechanical and tribological properties. In addition, wear mechanism, wear debris and roughness averages were studied. The outcomes indicate that both coatings show with dendrite structure due to rapid cooling rates. Hardness of the clad surface has improved than substrate material. The results of friction coefficient of specimen with Colmonoy-6 is lower than that of specimens Stellite-6 and substrate. Also, wear resistance of Colmonoy-6 has increased 49 times than substrate sample, which reveals that Colmonoy-6 laser cladding plays role on wear resistance. Adhesive and abrasive are the major wear mechanisms in the present study.
关键词： Wear debris,Microstructure,Stainless steel 304,Roughness,Wear performance,XRD,Laser cladding,Hardness
更新于2025-09-12 10:27:22