Laser Cladding Process Parameters Research Articles

Microstructural Evolution, Hardness and Wear Resistance of WC-Co-Ni Composite Coatings Fabricated by Laser Cladding.

This study investigated how process parameters of laser cladding affect the microstructure and mechanical properties of WC-12Co composite coating for use as a protective layer of continuous caster rolls. WC-Co powders, WC-Ni powders, and Ni-Cr alloy powder with various wear resistance characteristics were evaluated in order to determine their applicability for use as cladding materials for continuous caster roll coating. The cladding process was conducted with various parameters, including laser powers, cladding speeds, and powder feeding rates, then the phases, microstructure, and micro-hardness of the cladding layer were analyzed in each specimen. Results indicate that, to increase the hardness of the cladding layer in WC-Co composite coating, the dilution of the cladding layer by dissolution of Fe from the substrate should be minimized, and the formation of the Fe-Co alloy phase should be prevented. The mechanical properties and wear resistance of each powder with the same process parameters were compared and analyzed. The microstructure and mechanical properties of the laser cladding layer depend not only on the process parameters, but also on the powder characteristics, such as WC particle size and the type of binder material. Additionally, depending on the degree of thermal decomposition of WC particles and evolution of W distribution within the cladding layer, the hardness of each powder can differ significantly, and the wear mechanism can change.

Research on the Process of Laser Cladding Ni60 Coating on High-Nickel Cast Iron Surfaces

In order to achieve high-performance coatings on the surface of electric submersible pump impellers, it is crucial to optimize the laser cladding process parameters. Using Ansys 2021 R1 commercial software, a numerical simulation of laser cladding Ni60 powder on high nickel cast iron was conducted. The simulation utilized a 3D Gaussian heat source, parametric language, and life–death unit technology to replicate the characteristics of synchronous powder delivery laser cladding. The study focused on analyzing the temperature field cloud map and molten pool size under different laser power and scanning speeds, narrowing down the process parameter window, selecting optimized laser power and scanning speed, and assessing the changes in surface morphology, melting height and width, dilution rate, microhardness, and microstructure of the laser cladding coating. Results indicate that the coating width and thickness increase with higher laser power and lower scanning speeds. The microstructure consists primarily of dendritic, block, short rod, and long strip formations, and exhibits a tightly distributed and uniform grain structure. Furthermore, the microhardness of the coating shows a negative correlation with laser power and scanning speed. The optimal process parameters were determined to be a laser power of 1100 W and a scanning speed of 6 mm/s. A comparison with the simulation confirmed the effectiveness of the simulation in effectively guiding actual production.

A method for predicting the morphology of single-track laser cladding layer based on SO-LSSVR

The morphology of the cladding layer is directly affected by the process parameters of laser cladding. To improve the morphology of single-track cladding layer, it is necessary to accurately reveal the nonlinear relationship between the morphology and process parameters of laser cladding. Firstly, the single-track Ni60/10%WC cladding layer was preparate on the surface of 35CrMoV substrate, and the effects law of process parameters such as laser power, scanning speed and powder feed rate on the morphology of single-track cladding layers were investigated through single factor experiment. Then, the prediction model for predicting the morphology of single-track laser cladding layer was established by the SO-LSSVR. At the same, the prediction models based on ternary quadratic regression, SVR, and LSSVR were established for comparative analysis. Finally, the prediction results show that the MAPE, RMSE and R2 of the SO-LSSVR prediction model are better than the prediction results of the remaining three models. The proposed SO-LSSVR prediction model can accurately describe the nonlinear relationship between the process parameters and morphology of single-track cladding layer, which lays a foundation for the subsequent process parameter optimization to improve the morphology of cladding layer.

Prediction Method for High-Speed Laser Cladding Coating Quality Based on Random Forest and AdaBoost Regression Analysis.

The initial melting quality of a high-speed laser cladding layer has an important impact on its post-treatment and practical application. In this study, based on the repair of hydraulic support columns of coal mining machines, the influence of high-speed laser cladding process parameters on the quality of Fe-Cr-Ni alloy coatings was investigated to realize the accurate prediction of coating quality. The Taguchi orthogonal method was used to design the L25(56) test. The prediction models of the relationship between the cladding process and the coating quality were established using the Random Forest (RF) and AdaBoost (Adaptive Boosting, AB) algorithms, respectively. Then, the prediction accuracy of the two models was compared, and the process parameter features were screened for importance evaluation. The results show that the AB prediction model is more accurate than the RF prediction model and more sensitive to abnormal data. The importance evaluation based on the AdaBoost model shows that the scanning speed has a great influence on the height and surface roughness of the coating. On the other hand, the overlap rate is the most important factor in controlling the dilution ratio and near-surface grain size of high-speed laser melting coatings. In addition, the micro-hardness of the coating and the thermal effect of the substrate can be effectively enhanced by adjusting the laser power and scanning speed. Finally, it was verified that the AB prediction model could accurately estimate the quality indexes of the coating with a prediction error less than 6%. The results show that it is feasible to predict the quality of high-speed laser cladding with the AB algorithm. It provides a basis for the adjustment of process parameters in the subsequent quality control process of cladding.

Statistical-experimental modeling of the effect of process parameters on geometric characteristics of laser cladding of stellite 6 on SS316 using second-order regression

Applications of 316 stainless steel can be developed by laser cladding of the Co-based superalloys, which has multiple enhancement properties and creates a small heat affected zone. Quantitive investigation of the effect of process parameters on geometrical features and providing reliable models to achieve the desirable metallurgical bond, minimal structural defects, and predicting the dimensions of the geometry without conducting excessive experimental tests are an important issue. This study evaluate the effects of the main process parameters of laser cladding on geometric characteristics of stellite 6 using the response surface methodology. A quadratic model was developed for each of the geometric characteristics. Laser power, scanning speed, and powder feed rate ranged between 400 and 600 W, 6–10 mm/s and 12–20 gr/min, respectively, were considered as the input variables and height, width, penetration depth and dilution were considered as responses. The experiments were designed using the box-behnken method. The accuracy and fitness of the models were evaluated using analysis of variance method. The results indicated the R2 factors obtained for height, width, penetration depth and dilution are equal to 0.89, 0.98, 0.98 and 0.96 respectively. After obtaining the desirability factor of 0.795, the optimal set of process parameters were selected as laser power of 510 W, scanning speed of 10 mm/s and powder feed rate of 13 gr/min. Verification of the optimization was done by performing experimental test,which maximum 13 % difference between actual values and the predicted values was obtained.

Effect of laser specific energy on mechanical properties of Fe60 coatings by laser cladding

To reveal the effect of laser specific energy on the mechanical properties of Fe60 coatings, and determine the laser specific energy as well as the corresponding process parameters for the optimal mechanical properties of the coatings, Fe60 coatings were prepared on the surface of 304 stainless steels by laser cladding. The microhardness, tensile properties, and impact properties of the coatings were investigated at different laser specific energies by changing the laser power and scanning speed. The results show that the Fe60 coatings are mainly composed of cryptocrystalline martensite, carbides, a small amount of ferrite and residual austenite. Compared with the substrate, the microhardness of Fe60 coatings is significantly increased, the tensile properties of Fe60 coatings are reduced, the brittle cleavage fracture characteristics are presented, and the impact toughness of Fe60 coatings is slightly reduced. With the increase of laser specific energies, the microhardness, tensile properties, and impact properties of the coatings show a trend of increasing and then decreasing. When the laser power is 2300 W, the scanning speed is 11 mm/s, and the laser specific energy is 105 J/mm2, the coatings with the optimal mechanical properties can be obtained. The results can provide a reference for preparing Fe60 coating of excellent performance by adjusting the laser specific energy through synthetically coordinating the laser cladding process parameters.

Research and Development Status of Laser Cladding on Stainless Steel Alloys: A Review

Stainless steels as one of the most appealing structural material in many fields of industries because of its resistance to corrosion, high tensile strength, durability, temperature resistant etc. To improve its surface properties and overcome issues like large heat affected zones, poor surface quality, and limited dissolvability, researchers have explored surface modifications through laser cladding. This paper gives a detailed review about the work done in recent years, in the region of laser cladding of different grades of stainless-steel alloys with different coating materials highlighting on feeding ways of cladding material, laser cladding process parameters, types of lasers employed, types of coating & composite coating materials in enhancing the surface properties of the stainless-steel substrate and their relevant applications.

Multi-objective optimization of key process parameters in laser cladding Stellite12 cobalt-based alloy powder

Laser cladding (LC) process parameters have a substantial influence on coating morphology and mechanical characteristics; it is necessary to optimize key parameters for laser processing. In this study, Stellite12 cobalt-based alloy powder with excellent corrosion and wear resistance was selected as the cladding material. The multi-objective optimization model of the LC process was established by response surface methodology, laser power, scanning speed, and powder feeding rate as input factors, and the target response variables involve dilution, aspect ratio, and microhardness of the single-track cladding. Combined with variance analysis (ANOVA), the multi-objective optimization of laser power, scanning speed, and powder feeding rate was conducted. A single-track cladding layer with a dilution of 18.29%, an aspect ratio of 3.88, and a microhardness of 634.67 HV0.2 was obtained using the optimized process parameters. Errors between the predicted and actual values of single-track cladding dilution, aspect ratio, and microhardness were less than 8%, which verified the accuracy of the established model.

Analysis of the sequentially coupled thermal–mechanical and cladding geometry of a Ni60A-25 %WC laser cladding composite coating

In this research, a three-dimensional (3D) transient finite element model based on a sequentially coupled thermal–mechanical analysis (SCTMA) is proposed to simulate the evolution of the temperature field and stress field as well as the cladding geometry of the Ni60A-25 % WC laser cladding composite coating. Based on the thermo-physical properties of Ni60A-25 % WC powder and the design of the double ellipsoidal heat source model, a 3D finite element model of double-layer laser cladding with two channels is established. The evolution of the temperature field and the residual stress field at different laser process parameters are investigated to evaluate the quality of the cladding layer. The impact of different laser cladding process parameters on the cladding dimensions is investigated. The dimensions of the simulated molten pool are analyzed by fitting a polynomial curve. The simulation results show that the laser power is proportional to the temperature, and the temperature growth rate of the coating is significantly higher than that of the substrate. The scanning speed is inversely proportional to the temperature. The maximum temperature of the cladding is 1.5 times the maximum temperature of the substrate. The temperature growth rate of the cladding layer is twice that of the substrate. Due to the asymmetry of the heat source in the multi-pass cladding process, the laser energy absorption rate is not the same on both sides of the melted layer. The double ellipsoidal heat source model has a larger diffusion range in the un-melted powder, resulting in asymmetry in the width direction of the cladding layer. The analysis of the residual stresses in the cladding layer shows that the residual compressive stresses in all paths increase with the increasing laser power. The normal x residual compressive stress in the coating and the maximum residual compressive stress occur at the end of the laser beam scan. The residual compressive stress in all paths decreases as the scanning speed increases. The results show that the dimensions of the molten pool are proportional to the laser power and inversely proportional to the scanning speed. The cladding geometry can be calculated with polynomial fitting equations at a selected laser power (500 W–2800 W) and scanning speed (1 mm/s–8 mm/s). The error analysis of the simulation and the experimental results can validate the proposed finite element simulation model. The error in the molten pool size is less than 20 % for the simulation and experimental results.

Review on wear resistance of laser cladding high-entropy alloy coatings

The wear resistance of the part surface has become an important factor affecting its own service life. Laser cladding (LC), as a surface modification technology, can prepare a coating with good metallurgical bonding with the substrate, which can significantly improve the wear resistance of the material surface. High entropy alloys (HEAs) are an emerging coating material with excellent wear resistance. Therefore, this paper reviews the latest development status in wear resistance of laser cladding-high-entropy alloy coatings (LC-HEACs) in terms of the HEAs material system, LC process parameters, strengthening phase, amorphous phase strengthening, assisted cladding, and post-treatment. At the same time, this paper also expounds on the mechanism of LC-HEACs enhancing the surface wear resistance of materials, and the current research status of LC-HEACs in different engineering materials and application environments. Finally, the current research deficiencies, challenges, and future development trends of LC-HEACs in the field of wear resistance are also elaborated, and it is expected to provide some references for their future development and applications.

Optimization of Process Parameters of Laser Cladding on AISI 410 Using MEREC Integrated MABAC Method

Optimization of Process Parameters of Laser Cladding on AISI 410 Using MEREC Integrated MABAC Method

Influence of Powder Mass Flow Rates on Wear Resistance and Impact Toughness of Inconel 718 Surface Coatings

Optimum laser cladding processing parameters were obtained based on the study of various powder mass flow rates for the repair of 27SiMn steel parts using Inconel 718 powder. In this study, fusion coating process parameters were set according to the influence of powder mass flow rates on fusion coating properties. The cross-sectional microstructure, X-ray diffraction patterns, micro-hardness distribution, friction, wear properties, impact properties, and fracture morphology of the clad layers were investigated for the various process parameters. The results indicate that the volume fraction for the Ni3Fe phase increases and then decreases as the powder mass flow rate increases. The micro-hardness, friction properties, and impact properties of the samples followed the same trend as those of Ni3Fe. At powder mass flow rates up to 20 g/min, microstructures in the cladding layer tended to be uniform with microstructures with fine grains, and micro-hardness and impact toughness reached maximum values of 328.2 HV0.5 and 45.4 J/cm2, respectively, which show better mechanical properties and wear resistance.

Optimization of the Forming Quality of a Laser-Cladded AlCrFeNiW0.2 High-Entropy Alloy Coating

Laser cladding is an effective surface strengthening method widely used in the surface treatment of extreme operating components such as gas turbines, aviation engines, and nuclear facilities. However, traditional cladding layers struggle to meet the diverse application needs of extreme working conditions due to their single cladding material and poor forming quality. Therefore, this article selected the new-type high-entropy alloy as the coating material and optimized its laser cladding process parameters in order to obtain an AlCrFeNiW0.2 high-entropy alloy coating with an excellent forming quality. It was found that as the laser power increased from 300 to 1800 W, the AlCrFeNiW0.2 high-entropy alloy coating transitioned from the incomplete or near-melted state to the fully and over-melted state gradually, while the coating showed the opposite trend of change as the laser scanning speed increased from 0.002 to 0.008 m/s. And when the laser power was 1000 W, the scanning speed was 0.005 m/s, and the spot diameter was 0.003 m, the AlCrFeNiW0.2 high-entropy alloy coating with a low dilution rate (9.95%) had no defects such as pores and cracks, and achieved good metallurgical bonding with Q235 steel substrate, demonstrating excellent forming quality. These could provide valuable theoretical and technical guidance for optimizing the laser cladding process and forming quality of new-type high-entropy alloy coatings.

Parameters optimization for single-track laser cladding based on MPA-SVR and A-NSGA-III

Laser cladding as an emerging surface modification technology, the morphology of the single-track cladding layer is directly affected by the process parameters. To obtain the ideal cladding layer morphology, it is necessary to build the mapping relationship between the process parameters and the morphology and optimize the process parameters. A method for predicting the morphology of the single-track cladding layer is proposed by using the support vector regression optimized by the marine predators algorithm. Then, the adaptive non-dominated sorting genetic algorithm III is used for process parameter optimization to determine the optimal process parameters of laser cladding. The results of the validation experiments show that the aspect ratio of the optimized cladding layer has been improved by 41.78%, the dilution rate has been improved by 22.30%, and the wetting angle has been reduced by 35.20%. The proposed process parameters optimization method of laser cladding can significantly improve the morphology of the cladding layer.

Study on Mechanical Properties of AlFeCrMoNi1.8Nb1.5 Eutectic High-Entropy Alloy Coating Prepared by Wide-Band Laser Cladding

In this study, AlFeCrMoNi1.8Nb1.5 (at.%) eutectic high-entropy alloy (EHEA) coating was successfully prepared on the surface of M2 high-speed steel (HSS) by wide-laser cladding. The effects of laser defocusing amount, laser power, scanning speed, and preset powder thickness on the formation quality of the EHEA coating were studied by the orthogonal experimental design, then the mechanical properties of the coating prepared by water-cooled solidification under optimal process parameters were studied. The experimental results showed that the optimal laser cladding process parameters are defocusing with an amount of −30 mm, laser power of 4 kW, scanning speed of 3 mm/s, and preset powder thickness of 1.5 mm. The substrate exhibited a favorable metallurgical bond with the coating, characterized by a stable interface devoid of any holes or cracks. Furthermore, the coating, which was prepared using water cooling, displayed a finer lamellar eutectic structure comprising FCC and Laves phases. The microhardness of the coating (544 HV0.2) was significantly higher than that of the substrate M2 HSS (~220 HV0.2), accompanied by good wear resistance.

Research on the Thermal Behavior of Surface Texture on Laser Cladding Layer of Mold Steel

To extend the service life of mold steel and reduce the residual stresses generated during laser cladding to reduce defects such as surface cracks, this paper conducts a simulation study in terms of optimizing the laser cladding process parameters and pre-setting the surface texture. Firstly, using residual stress as an indicator, a three-factor, three-level orthogonal experiment was conducted using ANSYS on three factors: laser power, scanning speed, and spot radius, and then the experimental results were subjected to signal-to-noise ratio and extreme difference analysis to obtain the optimum process parameters: laser power of 800 W, spot radius of 1 mm and scanning speed of 20 mm/s. Subsequently, the mould steel was pre-textured under the optimum process parameters and the temperature and stress fields of the clad layers were compared with those without pre-texturing. The results show that the average residual stress in the pre-textured clad layer is 149 MPa, which is 58.56% lower than the average residual stress in the unpre-textured clad layer, which is consistent with the experimental results and verifies the feasibility of pre-texturing in the elimination of residual stress.

Influences of the cladding method and overlapping rate on the multi-channel overlapping of composite coatings

Composite surface coatings had poor flatness rates and unmelted gaps in the multi-channel overlapping process. The mathematical prediction models of the overlapping rate, flatness rate, and defect rate were established based on the single factor test to reveal the coupling effect of the overlapping rate on the flatness and defect rates (pore area and unmelted gaps) of coatings under different cladding methods. The large flatness rate and small defect rate were optimized to obtain the optimal overlapping rate under different cladding methods based on grey correlation analysis. Finally, the cladding efficiency was used as an index to determine the optimal cladding method. The model had a certain prediction ability. The flatness rate first increased and then decreased with the increased overlapping rate; the defect rate first decreased and then increases with the increased overlapping rate. The optimal overlapping rate was obtained with 30 % circular sequence overlapping to derive maximum surface flatness and the minimum defect rate. The coating could reach 13.986 mm2, and the cladding efficiency could reach 69.930 mm3/s at this time. Results showed that the multi-index grey correlation analysis had certain feasibility for the optimization of laser cladding process parameters. The work provides references for the multi-objective optimization of the surface properties of laser cladding composites as well as a theoretical basis for the comprehensive comparison of coating performance under different cladding methods and overlapping rates.

Multi-objective optimization of process parameters of laser cladding 15-5PH alloy powder based on gray-fuzzy taguchi approach

Laser cladding is a new surface treatment technology that is widely used for surface modification of metal parts, and the high quality of the surface geometry of the cladding layer can save a lot of resources for the company. To obtain high quality of the clad layer, the L25 Taguchi experiment of laser cladding process parameters was designed to laser-clad a single 15-5PH layer on the surface of 45# steel; the effect of process parameters on the surface morphology and dilution rate of the coating was determined by ANOVA; the optimal combination of process parameters was obtained by combining gray correlation and fuzzy inference system method. The ANOVA results show that the scanning speed among the laser cladding process parameters plays a key role in obtaining the best superposition of the four geometrical features of the cladding layer simultaneously; With the optimization objectives of larger clad width and height, smaller clad depth, and 30% dilution rate, the optimal combination of process parameters, (P: 600W, V: 500 mm min−1, F −1 : 1.3 r min−1), obtained based on the Gray-fuzzy Taguchi Approach, was compared and analyzed to find a significant improvement in the geometric quality characteristics of the optimized clad layer. The analysis of microstructure, physical phase, hardness, wear resistance and corrosion resistance showed that the 15-5PH clad layer was able to effectively enhance the surface properties of the 12Cr13 substrate. The optimization method proposed in this study can solve the problem of parameter optimization in the industrial multi-parameter and multi-response processes.

Numerical simulation and experimental study of the influence of coaxial powder feeding laser cladding process parameters on gas-powder flow

Laser cladding is an advanced manufacturing technology for preparing high-performance metallurgical coatings on metal substrates that is widely used in industrial production. In order to improve the powder utilization rate and reduce the waste of powder in the coaxial powder feeding laser cladding process, the Euler–Lagrange theory was used to establish the simulation model of gas-powder two-phase flow in laser cladding. Fluent was used to simulate the powder particle size, powder particle shape factor, carrier gas flow rate, and powder feed rate under different process conditions, and the results were verified by experiments. Through analysis, under the process parameters of a carrier gas flow rate of 4 L / min and a powder feed rate of 15 g / min, the powder utilization rate was high and the surface of the cladding layer was smooth. When the particle size was 100 mesh and the particle shape factor approached 1.0, the concentration of powder focus was higher and the convergence effect was the best. The influence of powder process parameters on powder convergence was comprehensively analyzed, which is of great significance for the subsequent optimization design of nozzle and the improvement of powder utilization in the laser cladding process.

Investigation of temperature field for the in-situ fabrication of particle-reinforced alumina ceramics coating via laser induction

Laser-induced aluminum thermal reaction was used to prepare a new iron particle reinforced alumina ceramic coating on the surface of TC4 titanium alloy. The aluminum thermal reaction heat generation in the on-line laser melting and coating process is fast and not easy to control, and its effect on the coating quality is unknown and usually neglected in the preparation process. In this paper, a numerical simulation model of a dual heat source containing the reaction heat is established. The temperature field of the new Al2O3-Fe composite coating and the thermal stress distribution pattern of the components were investigated. The effects of different laser parameters on the maximum molten pool temperature, thermal deformation and coating morphology of TC4 titanium alloy substrates were also discussed. The accuracy of the model is verified by the joint temperature acquisition experiment, which provides a reference for the selection of laser cladding process parameters. The simulation results show that the maximum temperature and volume of the melt pool increase significantly due to the coupling of the induced reaction heat, and the maximum temperature is not inversely proportional to the laser scanning speed, but directly proportional. The residual stress analysis shows that the residual stress on the coating is mainly the tensile stress along the laser cladding direction, which is the main reason for the transverse crack of the single layer coating after laser cladding.