Multi-track laser cladding is the primary technology used in industrial applications for surface reinforcement and remanufacturing of broken parts. In this study, the influence of processing parameters on multi-track laser cladding was investigated using a Taguchi orthogonal experimental design. A multi-response grey relational analysis (GRA) was employed to identify laser cladding processing parameters that simultaneously optimize the flatness ratio of the coating and the cladding efficiency. The optimal parameters setting found by GRA were validated experimentally. Results showed that the flatness ratio and cladding efficiency were closely correlated to the overlap rate and laser power, where the overlap rate shows the most significant impact on the flatness ratio and the laser power shows the most significant impact on cladding efficiency. Results from the validation experiment were within one percent (0.97% error) of the predicted value. This demonstrates the benefits of utilizing GRA in laser cladding process optimization. The methods presented in this paper can be used to identify ideal processing parameters for multi-response multi-track laser cladding processes or other industrial applications.

In order to improve the performance of the cladding layer, this study used the Taguchi orthogonal design to investigate the influence of laser power, scanning speed, gas flow, and SiC powder ratio on the micro-hardness and wear volume of the cladding layer. The results indicate that the SiC powder ratio was the major factor that had the main impact on the micro-hardness and wear volume of the cladding layer. The contribution of SiC powder ratio on the micro-hardness and wear volume are 92.08% and 79.39%, respectively. Through signal to noise ratio conversion and combining grey relational analysis, the multiple objectives optimization was attained. With the target of maximizing the micro-hardness and minimizing the wear volume simultaneously, grey relational analysis was applied to obtain the optimal processing parameters set and predict the corresponding grey relational grade. The error rate was 5.3% between the prediction and experimental validation. This study provides the guidance for optimizing multiple goals at the same time using grey relational analysis about the coating properties deposited by laser cladding in actual industrial applications. It provided theoretical basis for the processing parameters optimization with targeting the micro-hardness and wear resistance.

Laser cladding on curved surfaces is essential in industrial applications for restoration and remanufacturing of high-value parts. This study investigated the influence of different factors on clad width, clad height, and dilution rate in curved surface laser cladding with curved path. Mathematical models were developed using central composite designs to predict these geometric characteristics by controlling laser power, scanning speed, gas flow, and altering the outside radius of the cylindrical substrate. Analysis of variance and response surface methodology indicated that clad width increased with increasing laser power and reducing scanning speed. Clad height positively correlated to laser power and negatively correlated to the outside radius of the cylindrical substrate. Increasing the laser power while decreasing the scanning speed led to an increase in dilution rate. Afterwards, the geometric characteristics of the clad were improved by optimizing these factors with the target to maximize clad width and height as well as to minimize dilution rate. The difference between model predictions and experimental validations for clad width, clad height, and dilution rate were 3.485%, 3.863%, and 6.566%, respectively. The predicted accuracy was verified with these models, and they were able to provide theoretical guidance to predict and control the geometric characteristics of curved surface laser cladding with a curved path.

This paper investigated the correlation between the processing parameters and the properties of clad deposited by laser cladding on a curved surface. Mathematical models relating the processing parameters (laser power, scanning speed, gas flow, and overlap ratio) and clad properties (flatness ratio and pore area) were established by central composite design. Analysis of variance and experimental validation confirmed the validity of the models. The results indicated that the flatness ratio was negatively influenced by the larger scanning speed, gas flow, and overlap ratio, while the pore area was enlarged by the increasing of scanning speed, and increasing the overlap ratio lead to the pore area reducing at first and then increasing. Optimized processing parameters were obtained under the target of maximizing the flatness ratio and minimizing the pore area. The developed mathematical models enabled predicting the flatness ratio and pore area with optimized processing parameters. The validation experimental result verified the prediction accuracy of the models and displayed target improvement compared with the original central composite design. The results provide theoretical guidance in multi-track laser cladding on a curved surface for the prediction and control of the geometric characteristics of the coating and the optimization of the processing parameters. This research outcome provides guidance for the coating deposition application in crankshaft surface coating or surface restoration, rotary parts coating deposition, or complex shape tool manufacturing. It also forms the fundamental basis for the extensive application of multi-track laser cladding on curved substrates in the additive manufacturing industry.

Rare earth oxides have been proven for their ability to refine grains and have high melting points. In this paper, different contents of rare earth oxide La₂O₃ were added into the Ni60/WC-Ni composite coating, in order to study its effect on the coating properties. SEM observation confirmed that the grain was refined significantly after the addition of La₂O_3. Energy Dispersive Spectroscopy (EDS) was applied to investigate the composition and X-Ray Diffraction (XRD) was used to measure the residual stress in the coating samples. In addition, the microhardness and wear resistance of the samples were tested. The results showed that the dilution ratio of coatings with different additions of La₂O₃ was in the range of 2.4 to 9.8%, and the sample with 1.0% addition of La₂O₃ exhibited the highest hardness of 66.1 HRC and best wear resistance with a wear volume of 9.87 × 10⁶ μm³, and the residual stress increased from 159.4 MPa to 291.0 MPa. This implies that the performance of the coating has been obviously improved after the addition of La₂O₃.

The influence of processing parameters in laser engineered net shaping (LENS) on the properties of 316L stainless steel and titanium carbide (TiC) composite coating was studied. The key processing parameters were laser power, scanning speed, TiC powder ratio, and powder feed rate. Mathematical models were developed to investigate the micro-hardness, wear volume, and defect area of the coating. The accuracy of the models was examined by analysis of variance and experimental validation. Results showed that micro-hardness was positively correlated with TiC powder ratio. Increasing TiC powder ratio could reduce the wear volume. In addition, the wear volume displayed an increase then decrease with increasing laser power and decreasing scanning speed. Both scanning speed and TiC powder ratio showed a recognizable impact on the defect area. Reducing the scanning speed and TiC powder ratio can effectively reduce the defect area. The targets for the processing parameters optimization were set to maximize micro-hardness, minimize wear volume, and defect area. The difference between the model prediction value and experimental validation result for micro-hardness, wear volume, and defect area were 0.46%, 4.54%, and 8.82%, respectively. These results provide guidance for the LENS processing parameters optimization in controlling and predicting of 316L/TiC composite coating properties.