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oe1(光电查) - 科学论文

88 条数据
?? 中文(中国)
  • Optimizing Processing Parameters for Multi-Track Laser Cladding Utilizing Multi-Response Grey Relational Analysis

    摘要: 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.

    关键词: orthogonal experimental design,grey relational analysis,multi-track cladding,laser cladding

    更新于2025-11-28 14:24:20

  • Effects of tilt angle between laser nozzle and substrate on bead morphology in multi-axis laser cladding

    摘要: Laser cladding has been increasingly used for repairing and remanufacturing critical and high-value components due to its unique benefits such as high solidification rates and a small heat-affected zone. In laser cladding, tilt angle between a laser nozzle and a substrate has a significant impact on deposited bead morphology. To ensure the quality of laser cladding, the effects of tilt angle on bead morphology are investigated in this study. An analytical model is introduced to predict bead shapes for three tilting postures. In the first case, a substrate remains horizontal while the nozzle is tilted. All three parameters, including width, height, and peak point offset, will be influenced by the laser beam power distribution. In the second case, a substrate is tilted while the laser nozzle is kept axial to the substrate’s normal, the peak point offset will ascend along with the increasing of the tilt angle (gravity effect). In the third case, the laser nozzle remains vertical while the substrate is tilted, which leads to variations of cladding width, cladding height, and especially peak point shifting value. These parameters will be dependent on the integrated effect of gravity and the laser beam power distribution. A set of experiments is conducted to demonstrate the effectiveness of the proposed model. This study illustrates that the variation of cladding width and height with the tilt angle can be accurately calculated by the predictive model, and that the peak point shifting value is roughly smaller than 5% of cladding width when the tilt angle is less than 30°. These findings show that trajectory planning of multi-axis laser cladding can be optimized using an acceptable range of tilt angle between the laser nozzle and substrate.

    关键词: Bead morphology,Laser beam power distribution,Laser cladding,Tilting posture,Gravity effect

    更新于2025-11-28 14:24:20

  • Simplification and experimental investigation of geometrical surface smoothness model for multi-track laser cladding processes

    摘要: The formation of large area parts requires construction of multi-track laser cladding layers which are significantly influenced by the overlapping coefficient. The geometrical model of optimal overlap ratio to obtain least surface fluctuation of multi-track claddings is derived into a simpler form in terms of the aspect ratio of single-track clads. The error analysis further demonstrates the effectiveness of these models. Multi-track single layer claddings are fabricated at a series of overlap ratios under two process conditions. The surface states of cladding layers are then evaluated by two types of smoothness definitions with two fitting methods to study the optimal overlap ratios. The results show that the experimental optimum conditions identified by two methods are slightly different from each other. The theoretical prediction is in good agreement with the experimental one when the aspect ratio is great enough to support the model assumptions.

    关键词: Laser cladding,Multi-track clads,Overlap ratio,Geometrical model,Surface smoothness

    更新于2025-11-28 14:24:20

  • Effects of Substrate Preheating Temperatures on the Microstructure, Properties, and Residual Stress of 12CrNi2 Prepared by Laser Cladding Deposition Technique

    摘要: The 12CrNi2 alloy steel powder studied in the present paper is mainly used to manufacture camshafts for nuclear power emergency diesel engines. Laser cladding deposition is of great signi?cance for the manufacture of nuclear power emergency diesel camshafts, which has the advantages of reducing material cost and shortening the manufacturing cycle. However, due to the extremely uneven heating of the components during the deposition process, a complex residual stress ?eld occurs, resulting in crack defects and residual deformation of the components. In the present paper, 12CrNi2 bulk specimens were prepared on the Q460E high-strength structural steel substrate at different preheating temperatures by laser cladding deposition technique, and a ?nite element residual stress analysis model was established to investigate the effects of different preheating temperatures on the microstructure, properties, and residual stress of the specimens. The results of the experiments and ?nite element simulations show that with the increase of preheating temperature, the content of martensite/bainite in the deposited layer decreases, and the ferrite content increases. The proper preheating temperature (150 ?C) has good mechanical properties. The residual stress on the surface of each specimen decreases with the increase of the preheating temperature. The longitudinal stress is greater at the rear-end deposition part, and the lateral residual stress is greater on both sides along the scanning direction.

    关键词: substrate preheating,12CrNi2 alloy steel powder,residual stress,laser cladding deposition,microstructure and properties

    更新于2025-11-28 14:24:20

  • Laser cladding with grinding processing of orthogonal offset face gear

    摘要: To further develop the advantages of face gear drives and improve their anti-sticking performance and wear resistance, a novel method using laser cladding as the primary process is proposed; here, grinding processing is used as the secondary process, i.e., achieving tooth surface strengthening of the orthogonal offset face gear using two types of materials to form a material gradient based on a laser cladding technology. Then, grinding processing is performed using a five-axis grinding machining. First, according to the forming principle of the face gear tooth surface, we establish the coordinate system of the orthogonal offset face gear and the gear cutter coordinate system; we also derive the tooth surface equation of the virtual gear cutter and the tooth surface equation of the orthogonal offset face gear. Second, we research the principles of the laser cladding and establish a laser cladding test bed for the orthogonal offset face gear. Based on the analysis of the design of the cladding layer and the process parameters of the face gear, the selection of the scanning path, the heat accumulation during the laser cladding process, and the accuracy control of the scanning position, we perform a laser cladding experiment on the offset orthogonal face gear. Third, we establish the machining coordinate system of the face gear based on the machine tool structure and conduct a grinding experiment for the face gear after the cladding process. Finally, we analyze the morphology and hardness of the face gear after grinding. A bench test verification of the axle face gear transmission system is completed. The results show that the precision and surface hardness of the tooth surface are significantly improved after grinding. Meanwhile, the accuracy and feasibility of the laser cladding surface of the face gear are verified.

    关键词: Laser cladding,Generating grinding,Surface strengthening,Five-axis grinding machine,Face gear

    更新于2025-11-28 14:24:20

  • High Temperature Oxidation and Wear Resistance of In Situ Synthesized (Ti3Al?+?TiB)/Ti Composites by Laser Cladding

    摘要: (Ti3Al + TiB)/Ti composites were prepared on Ti6Al4V by laser cladding. The microstructures of the coatings were analyzed; the high temperature wear and oxidation properties of the coatings were investigated and compared with Ti6Al4V. Ti3Al and TiB particles were in situ formed through the reaction between Ti and AlB2. The reinforcements exhibited some crystallographic orientation relationships with a-Ti matrix, and a semi-coherent interface (Ti3Al) or a coherent interface (TiB) was obtained. The weight gain of the coating under each combination of temperature and time condition was 20 to 30 pct of the value of Ti6Al4V under the same experimental parameters. A denser and well-bonded TiO2 + Al2O3 layer was formed, effectively hindering the oxygen diffusion compared with the TiO2 layer on Ti6Al4V. EBSD result showed that the Al2O3 mainly assembled into clusters and located close to the interface while the outer area of the oxidation layer was mainly TiO2. The friction coefficients and wear losses of the coatings were lower than those of the substrates at 300 °C to 750 °C. The oxidation was a crucial factor affecting the wear performance at high temperatures. The protective effect of the TiO2 + Al2O3 layer and the formation of transfer films on the worn surface contributed to the improved wear resistance of the coating.

    关键词: TiB,Laser Cladding,Wear Resistance,Ti Composites,In Situ Synthesized,High Temperature Oxidation,Ti3Al

    更新于2025-11-28 14:24:20

  • Hyperspectral and thermal temperature estimation during laser cladding

    摘要: Although there is no doubt about the tremendous industrial potential of metal additive manufacturing techniques such as laser metal deposition, the technology still has some intrinsic quality challenges to overcome before reaching its industrial maturity. Noncontact in situ monitoring of the temperature evolution of the workpiece could provide the necessary information to implement an automated closed-loop process control system and optimize the manufacturing process, providing a robust solution to these issues. However, measuring absolute temperatures is not self-evident: wavelength-dependent emissivity values vary between solid, liquid, and mushy metallic regions, requiring spectral information and dedicated postprocessing to relate the amount of emitted infrared radiation to the material temperature. This paper compares the temperature estimation results obtained from a visible and near-infrared hyperspectral line camera and a conventional short-wave infrared (SWIR) thermal camera during the laser melting and cladding of a 316L steel sample. Both methods show agreeing results for the temperature distribution inside the melt pool, with the SWIR camera extending the temperature measurements beyond the melt pool boundaries into the solid region.

    关键词: temperature estimation,laser cladding,hyperspectral imaging,additive manufacturing,thermal monitoring

    更新于2025-11-28 14:24:20

  • Microstructure and properties of WC reinforced Ni-based composite coatings with Y <sub/>2</sub> O <sub/>3</sub> addition on titanium alloy by laser cladding

    摘要: In this study, WC reinforced Ni-based composite coatings with Y2O3 addition were deposited on Ti-6Al-4V titanium substrate by laser cladding. The phases, microstructure, microhardness and wear resistance of the composite coatings were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester and wear tester. The results showed that good metallurgical bonding was achieved between the composite coatings and substrate. The phases mainly were γ -Ni, TiC, TiB2, Ni3B, M23C6 and WC. Most of the WC was dissolved in small pieces of WC during the laser cladding process. The microhardness of the composite coatings was about 3 times that of the titanium substrate and the wear resistance of the composite coatings had a significant increase.

    关键词: titanium alloy,microstructure,Laser cladding,Y2O3,WC,Ni-based composite coatings

    更新于2025-11-28 14:24:20

  • Laser in-situ synthesis of high aspect ratio TiB fiber bundle reinforced titanium matrix composite coating

    摘要: In this study, coatings are fabricated with laser cladding technique on titanium alloy substrate using TiB2 powder (0.5 μm, 5 μm and 50 μm) as the cladding materials. The effects of different TiB2 particle sizes and different laser powers on the microstructure of laser cladding layer are investigated. The results reveal that the cladding layer of high aspect ratio TiB fiber bundle is formed when using 0.5 μm TiB2 as the cladding material under the condition of high laser power (2.5 kW) of TiB fiber bundle are formed when using 5 μm and 50 μm TiB2 as the cladding materials under the condition of different laser powers. Combined with the evolution of microstructure in the cladding layers, the formation mechanism of high aspect ratio TiB fiber bundle is discussed. Meanwhile, the cladding layer of high aspect ratio TiB fiber bundle exhibits the advantages of high hardness and high wear resistance, and the predominant wear mechanisms of TiB fiber bundle are cutting and fracture.

    关键词: TiB fiber bundle,Microstructure,Wear,Laser cladding,Hardness

    更新于2025-11-28 14:24:20

  • Computational and Experimental Investigation of Micro-Hardness and Wear Resistance of Ni-Based Alloy and TiC Composite Coating Obtained by Laser Cladding

    摘要: The influence of processing parameters on the micro-hardness and wear resistance of a Ni-based alloy and titanium carbide (TiC) composite cladding layer was studied. Mathematical models were developed to predict the micro-hardness and wear resistance of the cladding layer by controlling the laser cladding processing parameters. Key processing parameters were the laser power, scanning speed, gas flow, and TiC powder ratio. The models were validated by analysis of variance and parameter optimization. Results show that the micro-hardness is positively correlated with laser power and TiC powder ratio, where the TiC powder ratio shows the most significant impact. The wear volume decreased with an increasing TiC powder ratio. The targets for the processing parameter optimization were set to 62 HRC for micro-hardness and a minimal volume wear. The difference between the model prediction value and experimental validation result for micro-hardness and wear volume were 1.87% and 6.33%, respectively. These models provide guidance to optimize the processing parameters to achieve a desired micro-hardness and maximize wear resistance in a composite cladding layer.

    关键词: Ni35A + TiC composite,laser cladding,central composite design,wear resistance,micro-hardness

    更新于2025-11-28 14:24:20