Multi-layer Laser Cladding Research Articles

Microstructure, wear and corrosion resistance of Ni-based composite coating by multi-layer laser cladding

Using laser cladding technology to prepare coatings on the gear ring of the main wheel made of ZG42CrMoA, the composite coatings consisting of γ-Ni, M23C6, Ni3B, WC, and W2C. As the amount of WC nanoparticles increased, a "pinning" effect on dislocations hindered dislocation movement during wear, Comparative analysis showed a reduction in wear rate by 76.94 % and 72.80 % compared to the untreated substrate and high-frequency quenched substrate, respectively. Further, finite-element analysis indicated maximum compressive stress values of 274.37 MPa and 262.20 MPa during the impact and friction phases, respectively. This was lower than the corresponding values of the high-frequency quenched layer, which were 288.63 MPa and 283.16 MPa. The corrosion current density of the composite coating reduced by 87.98 % and 92.71 % compared to the untreated substrate and the high-frequency quenched substrate, respectively. Additionally, the electrochemical impedance amplitude of the composite coating was 72,456 Ω, which was substantially higher than that of the high-frequency quenched substrate (1270 Ω) and the untreated substrate (1717 Ω) by 570.5 % and 422.0 %.

Forming mechanism of single-channel multilayer laser cladding Fe60 process under different laser heat source operating mode

Continuous wave (CW) and pulsed wave are the two principal modes of operation used to control the laser heat source. Different laser heat source operating modes have an essential impact on the rapid cooling and heating temperature change rate during the cladding process, which directly determines the cladding layer quality. The laser cladding process is meaningful to quantitatively reveal the mechanism of single-channel multilayer cladding and forming under different laser heat source operating modes. In this article, a multi-field coupled 3D numerical model of the single-channel multilayer cladding process under different laser operating modes was proposed, and the thermal physical parameters of the cladding material were computed on the basis of Calculation of Phase Diagrams method. The mechanism of the impact of distinct operating modes on the multi-field coupled ephemeral evolution process of laser cladding was investigated by using the solid/liquid interface tracking technique, which comprehensively considers the light powder interaction between the powder waist beam and the laser beam under different operating modes. The temperature, flow, and stress fields were computationally solved for a single-channel multilayer cladding process. On the foundation of this study, the impact mechanism of pulse duty cycle and pulse frequency on the cladding behavior of single-channel and multilayers during pulsed laser cladding were dissected. The macroscopic morphology and microstructure of the cladding layer were observed by KEYENCE VH-Z100R ultra-deep field electron microscope, and the feasibility of the model was confirmed. This study provides a significant theoretical rationale for enhancing the cladding quality under different laser operating modes.

Quantitative assessment method of thermal cycle accumulation mechanism during the pulsed laser single-channel multilayer cladding process

Pulsed laser cladding provides a periodical thermal accumulation, enabling a greater temperature gradient and cooling rate inside the substrate, which can efficiently ameliorate the microstructure of the cladding layer. It is crucial to quantitatively investigate the mechanism of the interaction for the cladding process parameters on the transient evolution of the multi-field coupling to improve the cladding quality. In this paper, a 3-D model during the single-channel multilayer pulsed laser cladding process was constructed which is grounded on the temperature-variable physical properties parameters of the material. The integrated consideration in the masking impact of the molten powder waist beam on the pulsed laser beam, the molten pool liquid metal surface tension, the influence of buoyancy on the flow, and the transient evolution of the molten pool edge morphology. The temperature, flow, and stress fields of the single-channel multilayer cladding process were computed and resolved. The mechanism in multi-field coupling impact of laser pulse frequency, laser power, and pulse duty cycle on the single-channel multilayer cladding process was emphasized. The response surface equations between each influencing factor and the cladding temperature, temperature change gradient, and thermal stress were determined according to the response surface method, and the sensitivity of each parameter was attained from the Monte Carlo method. Using SEM to observe the profile and microstructure of the cladding layer, the material hardness distribution was measured experimentally, and the effectiveness of the model was confirmed. This research supplies an essential rationale for upgrading the quality of pulsed laser cladding layers.

Dynamic evolution of temperature field, flow field, and solidification behavior during multilayer multitrack laser cladding

During multilayer multitrack laser cladding, secondary melting and solidification in the interlayer lap zone have a significant impact on the mechanical properties of cladding coatings. However, mathematical modeling of the melt flow and solidification behavior of multilayer, multitrack laser cladding interlayer lap zones is lacking. In this paper, a 3D finite element model was established to investigate the mass and heat transfer processes in both lap and non-lap zones during the laser cladding of multilayer multitrack Fe-Cr-based alloys on 45# steel surface. A dynamic grid is used to track the free surface of the melt pool, while the enthalpy method is used to simulate the solid-liquid phase transition. The change in thermophysical properties with temperature, as well as the change in laser energy and alloy powder flow density in the lap zone, were taken into consideration. The influence of the number of cladding layers on the heat and mass transfer in the molten pool, remelting, and solidification in the lap zone was investigated, along with its intrinsic mechanism. The results show that the model can accurately predict the size and microstructural change law of coating layers, including the grain size of the lap region between layers. The melt pool temperature and grain size increase with the number of cladding layers, while the convection and cooling velocities decrease. In addition, the grain size in the lap zone of the cladding is larger than that in the nearby non-lap zone. Using solidification parameters extracted from the solidification front of the molten pool, changes in grain size and morphology were predicted for both the interlayer lap and non-lap zones. The numerical calculation results were consistent with the experimental measurements.

Investigation on laser cladding Fe-based gradient coatings with hierarchical enhanced wear resistance on U75V railway steel

This study focused on the multilayer laser cladding of 15–5 precipitation hardening (PH) steel coating on U75V railway steel for improved surface performance. The effect of pearlitic substrate dilution action with high carbon content on microstructures and wear performance of PH steel coating with four deposited layers was investigated. Results showed that each cladding layer consisted of a similar multiphase mixture of martensite, retained austenite, and NbC carbides in the case of stepwise changes in chemical compositions induced by dilution effects. The wear resistance of the multilayered PH steel coating is closely related to the deposited layer number, reflected in a gradient increase in the wear rate with the increasing cladding layers. A comparative analysis against the U75V substrate showed substantial wear rate reductions of approximately 95 % and 4.5 % in the first and fourth layers, respectively. Besides, the cross-sectional microstructures were analyzed in detail to reveal the underlying friction-induced microstructural evolution of the gradient coating. The refinement of martensite laths controlled by dislocation reaction and the friction-induced austenite to martensite transformation was responsible for the superior wear resistance. The current experimental results could provide a new strategy for designing hierarchical enhanced wearable gradient coating for surface modification in railway components.

Finite element simulation analysis of flow heat transfer behavior and molten pool characteristics during 0Cr16Ni5Mo1 laser cladding

0Cr16Ni5Mo1 super martensitic stainless steel has excellent weldability and is an economical material with a high life cycle and low cost, but there are few researches and applications of this material in additive manufacturing. In order to realize the application of 0Cr16Ni5Mo1 large-area laser cladding technology, the multi-track lap cladding of the material was studied. In this work, a multi-physical finite element model of multi-layer multi-track laser cladding was established, taking into account thermodynamic processes such as phase transition, Marangoni convection, and buoyancy. The flow and heat transfer behavior of 0Cr16Ni5Mo1 in multi-layer multi-track laser cladding process and the characteristics of the molten pool are studied. The research focused on the flow heat transfer behavior and molten pool characteristics of 0Cr16Ni5Mo1 during multi-layer multi-track laser cladding. The discussed aspects include the evolution history of the temperature field within the molten pool, flow field characteristics, molten pool dimensions, and dilution ratio under various laser powers and overlap rates. The results show that with the increase of overlap rate, the morphology of molten pools in different clad tracks will also change, and the flow rate, dilution ratio, and length of molten pools in the second track are negatively correlated, while the temperature and height of molten pools are positively correlated. As the laser power increases, all the characteristic quantities are positively correlated with it.

Study of the effect of overlap rate on the failure form, microstructure and wear resistance of multilayer laser cladding on grey cast iron surfaces

Laser cladding is less used in the repair of cast iron parts. In this paper, multiple layers of austenitic stainless steel powders with different overlap rates were laser clad by the process of adding a transition layer to explore the feasibility of multilayer cladding of grey cast iron. The study results show that the higher cladding layers tends to cause cracking and warping of substrate, and the increased overlap rate of the Ni transition layer can effectively inhibit these failures. The wear mass of Fe-based coatings with 33.3%∼66.7% overlap was 1.00–2.68 mg. After wear, the Fe2p and Ni2p potentials were shifted, the intensity of the O1s characteristic peaks increased, and the wear oxidation increased wear quality loss.

Effect of WC on microstructure, molten pool and properties of Ni based coatings by multi-layer laser cladding

Ni45 powder and tungsten carbide (WC) particles were added to laser cladding coatings by to improve the wear resistance and impact resistance of mechanical components. The microstructure and elements of the coatings were assessed using SEM and TEM. A high-speed camera was used to analyse the morphology of the molten pool during the cladding process. The wear resistance and impact resistance of the coatings were tested by a wear and impact testing machine. The reaction of WC in the molten pool releases a large amount of thermal energy, which gives the molten pool a faster flow rate. The flow rate increases rapidly at WC dosages of ≤10 wt% and more slowly at dosages >10 wt%. Flow in the molten pool causes the WC to break the columnar crystals in the pool, which form a large number of coarse cellular crystals. WC causes the coatings to precipitate more rich Cr hard phase and intermetallic compounds, which increases their abrasion resistance and impact performance. The wear rate of the coating containing 12 wt% WC was 91.59% lower than that of the Ni45 coating. However, the impact resistance was decreased by the stress concentration and brittleness of the WC.

Scanning Strategy of Multi-Layer and Multi-Track Laser Cladding for Radial Grooves of Annular Thin-walled Parts

Scanning Strategy of Multi-Layer and Multi-Track Laser Cladding for Radial Grooves of Annular Thin-walled Parts

Multi-layer laser cladding analysis and high-temperature oxidative wear behavior of cast iron with a low expansion coefficient

Laser cladding is among the critical processes for repairing and strengthening cast iron parts. To further improve the application of laser cladding on cast iron and provide a feasible technical approach for its surface cladding. In this paper, different alloy powders were clad on the surface of ductile cast iron and gray cast iron, commonly used cast iron materials in engine cylinder blocks. The multi-layer claddings of various powders on the cast iron surface were analyzed, and the oxidative wear behaviors of Fe-based coatings at high temperatures were discussed. The results show that the primary defects of the cladding layer were cracks and edge warping. The average stress relationship of each coating was: ∣dσNi∣<∣dσFe∣<∣dσCo∣, and the Ni-based layer internal stress was the minimum. The internal stress was mainly caused by the difference between the physical properties of the coating and the substrate, and cladding defects were easy to occur if the internal stress was too enormous. Ni-based coating with lower cladding stress can be a transition layer to avoid defects. The average wear of Fe-based coatings at room temperature, 100, 250, 500, and 750 °C was 2.83, 1.94, 4.46, 6.43 and 9.72 mg, respectively. The wear amount was the minimum at 100 °C. Temperature rising, the oxidation of the specimens intensified, and the wear amount increased.

Effect of intrinsic thermal cycles on the microstructure and mechanical properties of heat affect zones in laser cladding coatings on full-scale rails

Laser cladding (LC) wear-resistant alloy on the surface of pearlite rails has been proven to be able to improve their wear resistance significantly. However, the rapid cooling rate in LC will result in the formation of martensite structures with high hardness but low toughness in heat affected zone (HAZ), making the rails' service safety endangered. In this paper, a novel method was proposed to eliminate the un-tempered martensite in U71Mn rail based on the in-situ gradient tempering (IGT) effect induced by the intrinsic thermal cycles in multilayer LC. The influence mechanisms of interlayer and inter-track thermal cycles on the evolutions of microstructure and mechanical properties of HAZs were studied systematically. The results illustrate that the martensite in HAZs can be gradually tempered within the optimal IGT temperature range, and the tempering processing mechanisms are as follows: firstly, the ε-carbides precipitate from HAZs and then dissolve to form granular cementites. Then, the cementites form colonies of lathlike particles with similar orientations. Finally, a composite structure consisting of fine-tempered sorbite and granular cementites forms, in which the lamellar spacing of sorbite is <1/5 of that of the original pearlite, and the proportion of the high angle grain boundaries has increased by 2.2 times. During the tempering process, the microhardness of HAZs gradually decreases, accompanied by the increase of the bending properties therein. The ultimate bending strength and fracture strain of the specimens with fully tempered HAZs are enhanced to be about 1.6 and 5.5 times as much as those of the specimens with fully quenched HAZs, even much better than the substrate.

Influence of multi-layer laser cladding depositions and rail curvature on residual stress in light rail components

Rapid deterioration of critical rail components due to wear and fatigue is a significant challenge faced by the railway industry. Laser cladding has been applied to straight and curved light rail substrates which are particularly prone to these methods of degradation using a Stellite 21 hardfacing alloy. The influence of multi-layer cladding depositions, grinding-based finishing procedures and substrate rail grade on residual stress was analyzed using non-destructive neutron diffraction techniques. As cladding is a thermal process, microstructural changes from the heat inputs can result in a high internal stress state which reduces the loading capacity whilst a high hardness increases the likelihood of brittle failure. Stellite laser cladding depositions were found to result in low tensile residual stresses within the cladding layer, which become compressive in the heat affected zone (HAZ). Repeated thermal inputs from multi-layer cladding depositions did not negatively impact the hardness or microstructure after double layer laser cladding and increased the residual stress to 100 MPa at the cladding surface after grinding. Laser cladding on a curved rail substrate also produced increased internal stress after cladding due to higher strains resulting from the rail geometry but remained below the yield limit of the cladding and substrate material. These outcomes were compared to current literature indicating this critical combination of low internal strain and a cladding and HAZ hardness complementing the substrate material is difficult to achieve. Therefore, ensuring laser cladding is compatible with a variety of light rail components is essential in developing viable maintenance techniques to recondition critical railway infrastructure to avoid disruptive replacement procedures.

Thermomechanical Process Simulation and Experimental Verification for Laser Additive Manufacturing of Inconel®718

Laser cladding has emerged as a promising technique for custom-built fabrications, remanufacturing, and repair of metallic components. However, frequent melting and solidification in the process cause inevitable residual stresses that often lead to geometric discrepancies and deterioration of the end product. The accurate physical interpretation of the powder consolidation process remains challenging. Thermomechanical process simulation has the potential to comprehend the layer-by-layer additive process and subsequent part-scale implications. Nevertheless, computational accuracy and efficacy have been serious concerns so far; therefore, a hybrid FEM scheme is adopted for efficient prediction of the temperature field, residual stress, and distortion in multilayer powder-fed laser cladding of Inconel®718. A transient material deposition with powder material modeling is schematized to replicate the fabrication process. Moreover, simulation results for residual stress and distortion are verified with in-house experiments, where residual stress is measured with XRD (X-Ray Diffraction) and geometric distortion is evaluated with CMM (Coordinate Measuring Machine). A maximum tensile residual stress of 373 ± 5 MPa is found in the vicinity of the layer right in the middle of the substrate and predicted results are precisely validated with experiments. Similarly, a 0.68 ± 0.01 mm distortion is observed with numerical simulation and showed a precise agreement with experimental data for the same geometry and processing conditions. Conclusively, the implemented hybrid FEM approach demonstrated a robust and accurate prediction of transient temperature field, residual stresses, and geometric distortion in the multilayer laser cladding of Inconel®718.

Component mixing in laser cladding processes: From single-track to single-layer multi-track and multi-layer multi-track

In multi-layer multi-track laser cladding processes, the mechanical properties of the cladding layers are closely related to the microstructure and element distribution. However, the mixing process of the component cannot be predicted by the existing experimental conditions. A multi-layer multi-track laser cladding component prediction model is constructed to solve this problem. According to the multi-layer multi-track laser cladding model, the geometry of the cladding layer, and the element (Cr, Fe, and Ni) concentration distribution in the overlap zone and non-overlap zone are predicted. In addition, the effects of resistivity, dynamic viscosity, laser power, and active elements on the distribution of the cladding layer components were investigated. The results show that the uniformity of element distribution in the cladding layer is closely related to the convective mixing time and convective mixing intensity of the melt pool. Increasing the laser power, resistivity, or reducing the melt pool dynamic viscosity and sulfur concentration can increase the convective mixing time and convective mixing intensity of the melt layer, which helps to improve the uniformity of the melt layer group distribution. The concentration of Cr in the cladding layer increases with the number of the cladding tracks and layers, and the Cr concentration in the non-overlap zone of the first track of the first layer is lower than that in the overlap zone and other tracks. As the number of cladding layers increases, the concentration of elements in the overlap and non-overlap zones gradually tends to be uniform except at the edge of the cladding layer. In addition, the presence of sulfur in the melt pool can change the convection form of the melt pool.

In-situ monitoring and modelling of distortion in multi-layer laser cladding of Stellite 6: Parametric and numerical approach

Laser cladding is a direct metal deposition technique used for repair and rebuilding of worn-out components. In this process, the component is subjected to high heating and cooling cycles, which generate residual stresses and distortion affecting the part quality. The present work is to investigate and evaluate distortions generated during deposition using in-situ measuring method and also with numerical modelling. The role of different support conditions (simply, cantilever, and fixed) and process parameters (laser power, scan speed) on distortion are examined. A numerical model in COMSOL Multiphysics software was developed to generate thermal history and distortion in multi-layer cladding of Stellite 6. The temperature data shows large thermal gradients development along the thickness; allowing material to expand and contract at different rates, leading to substrate distortion. This was evidence in laser displacement sensor data and simulation. The results showed simple and fixed supports develop 40 - 50% and 60 - 70% less distortion than cantilever. Additionally, when the scan speed is decreased from 20 mm/s to 12 mm/s, distortion is lowered by 15 - 40%. An increase in laser power from 2400 W to 3400 W showed distortions to be 30 - 60% higher; while the second layer depositions have given 15 - 25% lower deflection. The simulation results are in good agreement with experimental values and reveals that support conditions are significant on distortion. Conclusion:- Laser cladding with simple and fixed supports developed 40 % - 50 % and 60 % - 70 % lower distortions than cantilever support; and increases with increase in laser power and decrease in scan speed.

Microstructural evolution and high-temperature oxidation of TiC/IN625 coatings fabricated by multi-layer extreme high-speed laser cladding

The multi-layer TiC/IN625 coatings were deposited on AISI 1045 steel substrate by conventional laser cladding (CLA) and extreme high-speed laser cladding (EHLA). The surface morphology, microstructure and high-temperature oxidation resistance of the TiC/IN625 coatings were characterized and compared. The results showed that the cladding speed has a significant effect on surface quality. Within the range of the set parameters, the best surface quality is obtained when the cladding speed is 49.8 m/min, where Ra is 11.75 μm and Sa is 13.17 μm. The microstructure of the TiC/IN625 coatings is dominated by dendrites. Smaller dendrites arm spacing and no apparent transition layer are found at the layer-to-layer interface in the EHLA sample. A two-layered oxide structure is formed in the cross-section of all samples. The EHLA sample exhibits a lower mass loss compared to the CLA sample, indicating that EHLA sample can withstand high-temperature oxidation. The improvement of high-temperature oxidation resistance is mainly attributed to the lower surface roughness, smaller dendrite size, smaller grain size, and higher amount of LAGBs.

Effects of Y2O3 on the microstructure evolution and electromagnetic interference shielding mechanism of soft magnetic FeCoSiMoNiBCu alloys by laser cladding

Laser cladding is one of the new techniques for additive manufacturing of metal alloy-based electromagnetic shielding materials. However, it is generally difficult to prepare alloys with ideal printability, soft magnetism and electromagnetic interference (EMI) shielding effectiveness (SE) using this technique. To improve the electromagnetic shielding performance of laser cladded Fe-Co based soft magnetic alloys, a new FeCoSiMoNiBCu alloy was prepared by laser multilayer cladding using metal powders added with different content of Y 2 O 3 . The results show that the FeCoSiMoNiBCu alloys prepared under optimized laser processing parameters exhibit excellent soft magnetism and electromagnetic shielding properties. The microstructure of the prepared alloys is mainly composed of α (bcc) phase, Fe 2 B, YFe 10 Mo 2 and B 6 Co 21 Mo 2 phases. The Y 2 O 3 powder has played significant effects on the soft magnetism and electromagnetic shielding properties of the alloys. When added with 1.5 wt% Y 2 O 3 , the alloy samples exhibit the highest saturation magnetization (186.2 emu/g) together with a superior EMI shielding effectiveness of 95 dB at 23.5 GHz, which is a 25–58% improvement compared the alloy without adding Y 2 O 3 . The mechanisms for the improved EMI shielding performance of the laser cladded FeCoSiMoNiBCu alloys depend on a synergistic effect of enhanced dielectric loss and ohmic loss; specifically, the α-Fe mainly promotes the dielectric loss, while the ohmic loss is enhanced by a “fish-bone” shaped phase composed of α (bcc) phase, Fe 2 B, YFe 10 Mo 2 and B 6 Co 21 Mo 2 . This study provides a new theoretical and technical guidance for the development of high-performance EMI shielding alloys using laser cladding technique. • A new FeCoSiMoNiBCu alloy with excellent electromagnetic shielding effectiveness was successfully prepared by laser cladding. • The microstructure evolution mechanism of Y 2 O 3 promoted laser cladding FeCoSiMoNiBCu alloys was clarified. • The influence of the type, size and proportion of in-situ magnetic phases on the FeCoSiMoNiBCu alloy’s electromagnetic shielding interference model was established by the experiments and first-principles calculations. • The electromagnetic shielding interference effectiveness of the laser cladding new FeCoSiMoNiBCu alloy was improved about 25–58%.

In-process monitoring of distortion and temperature in multi-layer laser cladding of Stellite 6 and Inconel 718 alloys

In laser cladding, the development of rapid heating and cooling cycles generates high residual stresses and thermal gradients that lead to induce unwanted distortion in the parts. The paper deals with online monitoring of temperatures and the associated distortions in multi-layer laser cladding using pyrometers and laser displacement sensors. The alloys deposited in the present work are Stellite 6 and Inconel 718, having similar thermo-mechanical properties. The results show that variation in thermal gradients due to rapid heating and cooling allows the material to expand and contract, generating substantial distortions. In the current investigations, Stellite 6 deposits generated 28%, 21%, 15% higher deflection at 12 mm/s, 16 mm/s, 20 mm/s scan speeds respectively; and 23%, 20%, 17% at 2400 W, 2900 W, 3400 W laser power compared to Inconel 718. Irrespective of the coating material, the second layer cladding induced 10% to 30% lower distortion than the first layer because of the reduction in temperature gradient. However, Inconel 718 clads measured 10% to 15% less melt pool temperatures than Stellite 6. The study reveals that different cladding materials deposited under similar process conditions have greater impact on distortion and temperature. At last, the investigations provide an optimum set of parameters to produce homogeneous cladding with moderate deflection and temperature for both the alloys.

In-situ synthesis of NiCoCrMnFe high entropy alloy coating by laser cladding

Improving the service life of the casting die is an important research topic. Due to the excellent wear resistance of the high entropy alloy, in-situ synthesis of a NiCoCrMnFe high entropy alloy coating on the H13 die steel through multilayer laser cladding was carried out in this study, and the microstructure, composition, phase, microhardness and wear resistance of the coating were investigated and compared with that of the untreated steel substrate. The results show that a high entropy alloy coating with a thickness of about 0.6 mm was formed, with its composition close to the design composition, and the phase is basically a single-phase FCC solid solution. Microhardness of the cladding layer is higher than 500 HV, over 2.5 times as that of the untreated substrate, and there are no microcracks around the indentations. Under the same friction conditions, the average width of the wear mark decreases from 0.71 mm of the substrate to 0.48 mm of the high entropy alloy layer, and the wear rate of the cladding layer decreases by 63.2% compared with the substrate. Meanwhile, hot erosion of the high entropy alloy coating by liquid Al alloy is far less serious than that of the substrate under the same condition. The in-situ synthesized NiCoCrMnFe high entropy alloy coating by laser cladding can significantly improves the surface microhardness, wear resistance and especially hot erosion resistance of the H13 die steel, which can be used to optimize the surface properties of the die.

Effect of multi-layer laser cladding of Stellite 6 and Inconel 718 materials on clad geometry, microstructure evolution and mechanical properties

The multi-layer laser cladding of high temperature resistance alloys i.e., Stellite 6 and Inconel 718 on SS316 was developed with an objective to investigate the effect of cladding materials on clad geometry, microstructure evolution and mechanical properties. The analysis was performed using Optical Microscope, SEM with EDS and Microhardness tester respectively. The results have shown a comparable difference in all the aspects of study. A 50% and 30% increment in clad height is measured while cladding at 12 mm/s and 16 mm/s scan speed as compared to 20 mm/s for both the alloys. The Inconel 718 deposits has shown 15–25% larger clad height, than Stellite 6. Also, under varying process parameters, 15–45% penetration depth and 10–15% higher dilution in Inconel 718 is obtained. SEM results have revealed that the microstructure evolution from top to bottom of the clad is nearly the same except at low laser powers. The decrement in microhardness is observed near the interface due to dilution and is higher in the first layer than the second layer. Whereas, the low dilution obtained in the second layer is because of the newly deposited layer over the substrate. The present work has given the optimum parameters (laser power and scan speed) as 2900 W and 20 mm/s for Stellite 6 and 3400 W, 12 mm/s for Inconel 718 respectively.