Clad Width Research Articles

Performance evaluation of TIG cladded in-situ TiC-TiB2 composite coating fabricated on AISI304 stainless steel

Tungsten inert gas (TIG) cladding is a surface modification technique used to deposit a coating with hard and resistance to wear material, which can improve the operational life of engineering components. In the present work, to improve the mechanical performance of AISI 304 stainless steel, in-situ TiC-TiB2 composite coating was fabricated through TIG cladding route by pre-placing Ti and B4C powder mixture at 3:1 wt ratio. The single line clad width and height was measured from the cross-sectional SEM images of the clad track. The microstructural analysis of the clad layer was accomplished through SEM images; however, EDS analysis was performed to study the distribution of different elements present in the clad layer. Almost a uniform clad layer with minor pores at the boundaries of the clad track was observed. The micro-hardness values variation towards the depth of the coating were evaluated for the clad layers deposited with different arc scanning speeds. Average value of micro-hardness was recorded between 800 and 1000 HV0.05, which was significantly higher than the substrate hardness.

Design of normal dispersion high nonlinear silica fiber and generation of flat optical frequency comb

<sec>The scheme of generating optical frequency comb mainly includes mode-locked laser, electro-optic modulation comb, nonlinear Kerr micro-resonator comb, and nonlinear supercontinuum comb. For the nonlinear supercontinuum comb scheme, the silica-based high nonlinear fiber with near-zero flattened normal dispersion is required. However the fiber dispersion varies along the fiber due to the fabrication inaccuracy. Furthermore, nonlinear supercontinuum comb generation based on the nonlinear fiber has not been systematically studied. In this paper, an optimal design of four-clad flat normal dispersion high nonlinear silica fiber with a triangular core refractive index distribution for the flat optical frequency comb generation is carried out. The effects of the fiber cladding width and refractive index on the fiber dispersion characteristics and cut-off wavelength are studied through using the finite element method mode solver. The optimally designed fiber can obtain relatively flat near-zero normal dispersion in a wavelength range of 1400–1700 nm, the dispersion range is –3–0 <inline-formula><tex-math id="M5">\begin{document}$ \rm{p}\rm{s}/(\rm{k}\rm{m}\cdot \rm{n}\rm{m}) $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M5.png"/></alternatives></inline-formula>, and the dispersion slope is close to 0 at nearly 1550 nm. The effective mode field area of the nonlinear silica fiber is about 11<inline-formula><tex-math id="M6">\begin{document}$ {\text{μm}}^{2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M6.png"/></alternatives></inline-formula>, and the nonlinear coefficient can reach 12.8<inline-formula><tex-math id="M7">\begin{document}$ {\rm{W}}^{-1}{\cdot \rm{k}\rm{m}}^{-1} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221115_M7.png"/></alternatives></inline-formula>.</sec><sec>Based on the electro-optic modulation pulse pumping the flat normal dispersion high nonlinear silica fiber, the flat optical frequency comb generation is systematically simulated with the generalized nonlinear Schrödinger equation. The time-frequency evolutions of a hyperbolic secant pulse, a Gaussian pulse and a super Gaussian pulse are simulated by using the X-Frog technology. The time-frequency spectrograms connect the time domain and the frequency domain of the pulse, clearly showing the change of pulse chirp during the propagation. The effects of various parameters on the optical frequency comb are studied, such as the fiber length, second-order dispersion, third-order dispersion, pulse peak power, pulse half width, pulse initial chirp, and pulse shape. An optical frequency comb with 3-dB flatness and about 40-nm bandwidth can be achieved based on hyperbolic secant pulse or Gaussian pulse pumping. Compared with the hyperbolic secant pulse and Gaussian pulse, the super Gaussian pulse can produce a flatter optical frequency comb. An optical frequency comb with 2-dB flatness and about 92-nm bandwidth can be achieved based on the super Gaussian pulse pumping. Therefore, based on the proposed high nonlinear fiber with normal dispersion , it is possible to realize an optical frequency comb with a repetition rate above 10 GHz, power flatness within 3 dB, and spectral bandwidth of about 40–90 nm. The simulation results are beneficial to promoting the localization of normal dispersion high nonlinear silica fiber and its application in flat optical frequency comb.</sec>

A lumped parametric analytical model for predicting molten pool temperature and clad geometry in pre-placed powder laser cladding

Pre-placed powder laser cladding is one of the simplest laser-based deposition techniques, having high material usage efficiency and capable to provide sound clad quality. However, the quality along with the geometrical aspects of the deposited layer depends on various energy transfer mechanisms controlled by process parameters. Energy transfer phenomena include the partial absorption of the laser radiation by metal powder layer, melting of the powder layer and transmission of energy to the substrate, along with the losses, like convective heat transfer to the atmosphere and conductive heat transfer to the bulk material. Theses phenomena all together defines the molten pool temperature, which needs to be analyzed to control the geometrical features of the clad and dilution by optimizing the process parameters. Therefore, a lumped parametric analytical model has been formulated and presented in this work for the pre-placed laser cladding process considering energy transfer and loss mechanisms along with the surface tension phenomena of the molten material to predict the molten pool temperature, clad geometry and substrate dilution. The developed model is validated using the experimental results of molten pool temperature of the clad layer, clad width and height as well as the percentage dilution. A continuous mode Yb-Fiber laser system with maximum available laser power of 220 W is used for the deposition of Inconel 625 powder on AISI 304 stainless steel substrate.

Laser cladding of Inconel 713 LC with Stellite 31 powder: statistical modeling and optimization

In the present study, laser cladding of Inconel 713 LC alloy with Stellite 31 powder was carried out using a 400 W pulsed Nd:YAG laser. Central composite design was employed to study the influence of input variables including pulse width, laser frequency, and laser speed on the output responses such as the clad geometry (clad height and clad width), dilution ratio (DR), and hardness. The results indicate that that the pulse width and laser frequency have a direct influence on the clad width, and DR but a reverse influence on the clad height and hardness. However, the influence of laser speed is the opposite of the influence of pulse width and laser frequency. The results depict that the hardness value decreases when the DR raises. By increasing the DR, the concentration of Co and Cr elements in the coating layer reduces, leading to a drop in the hardness. Simultaneous optimization was employed to optimize the cladding process. The pulse width of 12.19 ms, laser frequency of 20 Hz, and laser speed of 4.85 mm s−1 were found as the optimum parameters. The optimum sample has the hardness value of about 480 ± 5 Hv. This value is significantly higher than the hardness value of the substrate (355 ± 3 Hv). The cobalt solid solution phase and Cr7C3, Cr3C2, W2C, and WC x carbides are observed in the clad zone of the optimum sample.

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

Laser-based Directed Energy Deposition (DED-LB) represents a production method of growing importance for cladding and additive manufacturing through the use of metal powders. Yet, most studies utilize substrate materials with thicknesses of multiple millimeters, for which laser cladding of thin-sheet substrates with thicknesses less than 1 mm have only been scarcely studied in the literature. Most studies cover the use of pulsed laser sources, since sheet distortion due to excess energy input is a key problem in laser cladding of thin-sheet substrates. Hence, the authors of the present investigation seek to expand the boundaries of cladding thin-sheet substrates through the use of a high-speed laser cladding approach which utilizes a continuous-wave, ytterbium fiber laser and traverse speeds of 90 mms−1 to clad stainless steel sheets with a thickness of 0.8mm. Furthermore, fundamental process–property relationships for the target values of clad width, clad height, and dilution depth are studied and thoroughly discussed. Additionally, process maps for the target values are established based on manifold experiments, and the significance of process parameters on target values is studied using analysis of variance. The results demonstrate that clad widths as high as 1413 μm and dilution depths as low as 144 μm can be obtained by high-speed laser cladding of thin-sheet substrates. Thus, pathways toward thin-sheet substrates with enhanced performance are opened.

Parametric investigation and optimization for CO2 laser cladding of AlFeCoCrNiCu powder on AISI 316

Abstract The purpose of the current investigation is to analyze the effect of the operating parameters of laser-assisted cladding process on clad height, clad depth, clad width and the percentage dilution in a cladding of AlFeCuCrCoNi high-entropy powder on SS-316 through CO2 laser and to optimize the cladding process parameters for optimum dilution. The experiments were designed by the full factorial method and analyzed by ANOVA. The analysis results indicate that dilution is most influenced by scanning speed followed by the powder feed rate. The outcomes of the single clad profile in terms of dilution, microhardness, composition and the microstructures produced in various cladding conditions are investigated briefly, and through which the optimum set of laser cladding operating parameters for maximum hardness of the clad material is determined. The optimum cladding conditions in the experimental range were obtained at 4 g/min powder feeding rate, 500 mm/min laser scanning speed and 1.1 kW laser beam power through multi-response optimization. Furthermore, the multi-track coating with 60% overlapping ratio was deposited using optimized parameters. The wear behavior of multi-track coating was determined using pin on disk wear apparatus with applied load of 20 N, sliding speed of 300 RPM and test duration of 15 min. The pin on disk wear test results indicates that the friction coefficient of SS-316 is larger than that of high-entropy alloy cladded SS-316. The wear resistivity of SS-316 improved by 40.35% after laser-assisted high-entropy alloy coating, which confirms that the laser cladding layer plays an essential role in enhancing the wear resistance capability of austenite steel.

Effect of CO2 Laser Fluence on Cladding Geometrical Dimensions Alternations

Geometrical dimensions could play a potential role in the function of laser cladding of nickel-base powder on the cold-rolled carbon steel substrate. The geometrical dimensions and their impact on the efficiency of the process of laser cladding of nickel-base powder (Ni -10wt% Al) on cold rolled 0.2% carbon steel substrate was investigated. This work focused on the effect of laser-specific energy input of CO2laser. The geometrical dimensions of cladding regions are including cladding width, cladding height, depth of dilution, contact angle, dilution area, cladding area, and heat-affected zone dimensions determinations. The laser power (1.8 kW) was used at different traverse speeds (1.5, 3.6, 5, 7.1, 8.6, 12.5 mm/s) with (3mm) laser beam diameter. The feed rate was kept constant after many preliminary claddings at approximately 11 g/min. Fluence values ranged from (48-400J/mm2), and the power density value was (255W/mm2). A minimum dilution percentage (25%) was obtained at the highest fluence value (400 J/mm2). Observations were measured using an optical microscope, scanning electron microscopy, and Image software. Obtained results indicated that the increase in the fluence leads to an increase in height of cladding, HAZ region but lower depth of dilution

Integrated control of molten pool morphology and solidification texture by adjusting pulse duration in laser additive manufacturing of Inconel 718

Both single-track and bulk Inconel 718 samples were fabricated using pulsed laser additive manufacturing to investigate the effect of pulse duration on the molten pool morphology and the solidification texture. For single-track depositions, clad width, remelting depth, dilution ratio and peak molten pool temperature decrease, while clad height, clad area, minimum temperature and molten pool lifetime increase with the increase of the pulse duration. The fusion line of the molten pool in transverse direction is pan-like at a short pulse duration (20 ms), and gradually turns circular (60 ms) as the pulse duration increases. For bulk samples, uniform grains with a strong fiber texture are established for a short pulse duration. In contrast, alternatively distributed coarse grains in the overlapping region and fine grains at the center of the molten pool with a weak cube texture are obtained for a long pulse duration. In addition, samples fabricated with short pulse durations contain less volume fraction of Laves phase than that with long pulse durations. Pulsed laser additive manufacturing has the potential for texture control and in-situ production of components with functional graded textures.

Process, microstructure and microhardness of GH3039 superalloy processed by laser metal wire deposition

Laser metal deposition has high build rate and it is suitable for fabricating parts with larger sizes. Using the metal wire as feedstock material in laser metal deposition is a potential and promising approach compared with other metal additive manufacturing technologies, due to the metal wire is with lower cost, higher material efficiency and less pollution to environment. However, the experience and development activities relevant to metal wire based additive manufacturing are relatively limited. In this work, laser metal wire deposition was conducted to fabricate single-track cladding layers of GH3039 superalloy at different processing parameters, the empirical models and correlations between the main processing parameters (laser power (P), laser scanning speed (V) and wire feeding rate (F)) and geometrical characteristics (clad width (W), clad height (H), penetration depth (h), dilution (D) and wetting angle (θ)) of the cladding layers were studied by employing the combined parameter PαVβFγ and regression analysis (RA) method, which provides the possibility of predicting the geometrical characteristics under the applied processing parameters. To verify the correctness of the empirical models and study the layer-by-layer problems, the multi-layer single-track thin wall of GH3039 superalloy was fabricated and investigated. Furthermore, the microstructure and the microhardness of the cladding layers which may be aid for facilitating the industrial applications of laser metal wire deposition were also studied.

Analytical modeling and experimental study of laser powder-fed additive manufacturing on curved substrates

To explore the forming mechanism and the evolution laws of cladding geometry with process parameters on curved substrates for laser powder-fed additive manufacturing (LPF-AM) processes, based on the laser beam distribution and the cladding forming theory of horizontal and tilted substrates, analytical models for cladding geometric characteristics in the vertical and tilted postures of nozzles were established. LPF-AM experimental research on a curved substrate of AISI 304 steel was carried out, and the theoretical results were discussed and compared with the experimental data from the perspective of the curvature radius of the substrate, powder feed rate, scanning speed, and tilt angle of the nozzle. The results showed that the tilt angle of the nozzle was the most critical factor for the laser irradiation area and cladding width; moreover, the cladding width increased gradually as the tilt angle of the nozzle increased. The curvature radius of the substrate, powder feed rate, and scanning speed had a significant influence on the cladding height. Due to the effects of gravity, surface tension, and viscous shear force, the peak shift was proportional to the powder density and the tilt angle of the nozzle. The predicted values of the analytical models fit well with the experimental results. The prediction accuracies of the cladding width, cladding height, and peak shift theoretical models were 98.97%, 91.30%, and 76.85%, respectively. This study provides deeper insight into the ensuing cladding geometrical characteristics using LPF-AM on curved substrates.

High productivity fluence based control of Directed Energy Deposition (DED) part geometry

Successful and efficient hybrid manufacturing consisting of Directed Energy Deposition (DED) followed by milling as a postprocess requires that material deposited during the DED step be geometrically consistent and slightly larger than the desired final, machined dimensions. DED clad width is directly correlated to meltpool energy, while powder fluence directly correlated to DED clad cross-sectional area. Due to heat accumulation into the DED part during deposition, meltpool energy does not remain constant without modification of DED process parameters over the deposition cycle. Meltpool energy is typically managed by decreasing the laser power to reduce the energy fluence into the meltpool – though this technique limits DED productivity. If the working distance and laser optics within the deposition head are static, energy fluence reduction can also be achieved by increasing deposition head feedrate. Modifying powder mass flowrate through the deposition nozzle to maintain powder fluence into the meltpool allows for both the clad geometry to be maintained while also increasing the productivity of the DED process. Numerical simulation of the heat flow in a DED thin wall part was used to derive laser energy fluence values to maintain a constant meltpool energy. Derived values were tested using both the laser power and feedrate to moderate energy fluence into the meltpool. Results are compared to a thin wall deposited without meltpool energy control. Clad geometry variation and cycle time are both shown to reduce when using a feedrate-based meltpool energy control method as compared to laser power-based meltpool energy control or no meltpool energy control, increasing the geometric accuracy for postprocess machining and productivity.

Dilution and Aspect Ratio Properties on Performance of Laser Deposited Ti-Al-Si-Cu/Ti-6Al-4V Composite Coatings

In spite of the fact that Laser additive manufacturing (AM) processes have a similar material additive manufacturing theory, each AM procedure has its particular features in terms of operational materials and applicable situations. In recent years, additive manufacturing techniques have been acquainted as a promising technique to generate metallic parts since they can annihilate the familiar problems associated with conventional techniques. The results of the investigation showed that as the transverse speed increases, the material that is distributed to the substrate per unit length decreases and therefore that there is an inverse relationship with clad width, melt pool depth and clad height. Hence as the scanning speed increases the width if the height is smaller and the depth of the pool will be smaller too. The results indicate that the specimens manufactured at 900 W, had a decrease in dilution by 3.83%, 1.29% for Ti-Al-11Si-5Cu and Ti-Al-12Si-2Cu respectively when the scanning speed is increased. However, for Ti-Al-13Si-6Cu, there is an increase in the dilution by 1.06%, which can be attributed to the increase of the deposit area below the substrate than above. The results evidently show that increasing the laser scanning speed, increases the aspect ratio of the specimens for laser processing condition 900 W. This relationship is observed in attribution to the clad height being reduced as the scan speed is increased. Moreover, the varying scanning speed influences the clad height more significantly than the clad width; hence, the significant increase in the aspect ratio.

Advances in the understanding of the annular laser beam wire cladding process

This paper experimentally studies the influence of conventional process parameters (laser beam power, P, workpiece, and wire feeding velocities), and the nominal workpiece irradiation proportion WIPN parameter, on ALB-WC process stability and generated clad geometry. The study was based on an extensive set of single clad experiments using stainless steel AISI 316L wire of 0.6 mm diameter and a stainless steel AISI 304 workpiece. The results show that the laser beam power required for a stable process increases non-linearly with WIPN, and this relationship can be described by quadratic regression. An increase in either the workpiece or wire feeding velocity respectively causes a reduction or enlargement of the stability region in the P-WIPN stability diagrams. The influences on stability diagrams are explained by means of the increase in the nominal WIPN to the effective WIPE, as a result of the clad height generated. With respect to clad geometry, it was shown that an increase in the WIPN causes a decrease in the dilution ratio, which is linearly correlated with the workpiece and melt pool temperatures, while clad width and height are not influenced by the WIPN. The paper further explains the complex influences of the process parameters observed on process stability and generated clad geometry using a phenomenological description of the ALB-WC process at a low and high nominal WIPN. For this purpose, heat transfer, Marangoni flow, and laser beam reflections are considered qualitatively and supported by IR and visual images of the wire-end and melt pool as well as the workpiece and melt pool temperatures.

Selection of modes for laser cladding of PR-08Kh17N8S6G powder

A brief analysis of powders used in the industry for surfacing on the work surfaces of critical parts is given in order to increase their wear resistance. The results of experimental studies on the choice of parameters of gas-powder cladding modes are presented. The cladding process was carried out by a laser robotic complex with a coaxial feed of powder to the surfacing zone. The substrate used steel grade 08H18N10T, which was applied to the melt of wear-resistant powder grade PR-08H17N8S6G. The use of ytterbium fiber laser allowed to reduce the heat supply to the surfaces, which significantly reduced the residual stresses in the workpiece. Variable parameters of the laser cladding process were the output power of laser radiation, processing speed, and powder mass flow rate. During visual inspection, the absence of pores and cracks were used as the estimated indicators of the cladding. The study of macro geometry single clad track was conducted on cross section of the clad. During measurements, the quality of a single clad track was determined by its geometric dimensions: clad height, clad width, contact angle between the tangent to the cladding surface and the substrate plane, as well the depth of the mixing layer of the surfaced and substrate materials. According to the results of experimental studies of the selected optimal mode, providing a cladding track with a clad height above 1 mm; clad width 2.5 mm; the depth of the mixing layer – 0.2 mm; contact angle between the tangent to the clad surface and the substrate more than 50º. This work was financially supported by the Ministry of Science and Higher Education of the Russian Federation. Agreement on the provision of subsidies No. 075-15-2019-1833 dated December 03, 2019. Unique identifier PNI RFMEFI60419Kh0245.

A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load

Metal cloth seals have been used increasingly in gas turbines due to their flexibility and superior leakage performance. Leakage performance of a metal cloth seal depends on operating conditions, slot and geometric dimensions. These parameters need to be investigated for the best leakage performance. In this study, pressure drop and critical geometric parameters of typical cloth seal form are investigated with an experimental setup. Slot depth, cloth width, sealing gap, shim thickness, surface roughness, pressure drop, offset and mismatch are selected parameters for the screening experiments. Sixteen experiments were conducted following a two-level Resolution IV fractional factorial experiment design for eight parameters. The results indicated that strong parameters for the leakage performance are pressure drop, cloth width, slot depth and offset. Leakage rate is increased with an increase in slot depth, gap, shim thickness, pressure drop and mismatch. During screening experiments, the experiment with minimum flow rate has 86% lower leakage rate than the experiment with maximum flow rate. For main experiments, a Box-Behnken experiment design is applied to analyze nonlinear effects of four strong parameters on the leakage rate. A closed-form equation is derived based on the data and presented in this study.

Prediction modelling and process optimization for forming multi-layer cladding structures with laser directed energy deposition

In the laser Directed Energy Deposition (DED) manufacturing of parts, severe deformation caused by the uneven geometric characteristics of a multi-layer deposition fusion area occurs extremely easily due to the complexity and insufficient understanding of the process. The above results in a significant decline in the overall geometric quality of the parts. To study the influence of the laser DED process parameters on the geometric characteristics of multi-layer cladding, a response surface method was used to carry out an experimental study of the multi-layer cladding structures. Statistical prediction models of multi-layer cladding manufacturing were established among the laser power, scanning speed, powder feeding rate, lap ratio and cladding width, cladding zone area, fusion zone area, and flatness ratio. The accuracy, adaptability and relevance of the models were verified. The influence of each process parameter on the geometric characteristics of the multi-layer cladding structure was analysed, and the laser DED process parameters were optimized. Experimental results show that the surface forming quality of specimens processed with optimized process parameters is good. Relative errors between the experimental and predicted values of the geometric characteristics of specimens are less than 9%; thus, the prediction models can suitably predict and control the geometric characteristics of a multi-layer cladding structure. The proposed optimization of process parameters can significantly improve the geometric quality of parts and has substantial value in engineering applications.

Multi-response optimization in laser cladding process of WC powder on Inconel 718

In this study, laser cladding process of WC on Inconel 718 is investigated. Response surface methodology (RSM) benefiting from the desirability approach is used to achieve cladded layer of proper geometry with minimum dilution, porosity, cracks, and highly efficient process. In order to validate the models, confirmation experiments are carried out and the results indicate that the laser power is the dominant factor affecting the dilution and clad width, while porosity and cracks are highly affected by scanning velocity. Furthermore, adhesion test results and subsequent hardness testing suggest good bonding of clad layer to the substrate as well as desirable quality of clad.

Numerical simulation and experimental study on austenitic stainless steel by laser assisted metal deposition (L-MD)

The Laser assisted metal deposition (L-MD) is under the category of direct energy deposition (DED) process, and produce components with excellent metallurgical properties and full density. The temperature induced in the melt-pool, temperature gradients, solidification rate and laser interaction with powder material is very difficult to understand during L-MD process. Therefore, finite element analysis is done on L-MD to understand thermal behaviour which governs the microstructure characteristics (grain size and morphology). The input parameters of L-MD are scanning rate, powder feeding rate and laser power on the clad height and width and also investigated the variations of solidification rate and temperature gradient at each process parameter. The significant rise in clad width and height with laser power and powder feeding rate whereas descend with scanning rate are observed. The simulated clad width and height are well agreed with the experimental results. The scanning rate shows the significant impact on the magnitude and morphology of the microstructure.

Process parameters optimization of single-track laser cladding for 45 steel gear remanufacturing

In order to research the optimal combination of process parameters for the remanufacturing of 45 steel gear with RCF104 alloy powder, three-factor and five-level orthogonal experiments of laser power, scanning speed and powder feeding speed were carried out on 45 steel substrate. The best process parameters combination was selected by considering the shape coefficient of the cladding layer, dilution rate, cladding width and cladding height. The microstructure of the cladding layer was analyzed, the horizontal and vertical microhardness of the cladding layer was measured. The results show that the optimal combination of process parameters was laser power 448 w, scanning speed 6 mm/s, powder feeding speed 9.0369 g/min. The analysis of variance shows that the laser power and scanning speed were the main factors influencing the cladding width and the scanning speed had a significant influence on the cladding height and shape coefficient. The microstructure analysis of cladding layer shows that planar crystals, cellular crystals, columnar crystals, dendrites and equiaxed crystals changed gradually from bottom to top. The average microhardness of the cladding layer was 672.2HV, which was 3.08 times of the matrix hardness.

An Integrated Method for Multi-Objective Optimization of Multi-Pass Fe50/TiC Laser Cladding on AISI 1045 Steel based on Grey Relational Analysis and Principal Component Analysis

As an essentially multi-input multi-output process, determination of optimal conditions for laser cladding normally requires multi-objective optimization. To understand multi-response coupling, the effects of processing parameters on the morphology quality of multi-pass laser claddings of Fe50/TiC on medium carbon steel AISI 1045 were investigated based on composite central design using response surface methodology. Multiple responses, including clad width, flatness, and non-fusion area, were transformed into a single objective through grey relational analysis, with weights objectively identified by principal component analysis. The correlation between grey relational grade (GRG) and process parameters was established by regression analysis. The results show that the GRG response model has excellent goodness of fit and predictive performance. A validation experiment was conducted at the process condition optimized for maximum GRG. The relative error of the predicted optimal GRG is 4.87% whereas those of interested individual objectives, i.e. clad width, flatness, and non-fusion area, are 5.73%, 2.97%, and 6.73%, respectively, which verifies the accuracy of the established model. The investigation of mechanical properties suggests the hardness of substrate can be improved from 20 HRC to 60 HRC and wear resistance to over 8.14 times better.