Microstructure and properties of a laser cladded NiCrBSi alloy coating

2020 ◽  
Vol 62 (7) ◽  
pp. 698-702
Author(s):  
L. Yinghua ◽  
W. Kaiming
Keyword(s):  
Dilution Rate ◽  
Laser Power ◽  
Feeding Rate ◽  
Scanning Speed ◽  
Alloy Coating ◽  
Processing Parameters ◽  
Powder Feed Rate ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
Scanning Electron

Abstract Laser cladded NiCrBSi alloy coating was fabricated on the surface of a 42CrMo roll using a 6 kW fiber laser. The effects of the laser power, scanning speed and feeding rate on the cladding layer form, size, dilution rate, microstructure, and hardness of coating were studied by using optical microscopy (OM), scanning electron microscopy (SEM) and a microhardness tester. The results show that the microstructure, size, dilution rate and hardness of the cladding layer had changed with an increase in laser power, powder feeding rate and scanning speed. The appropriate parameters of the laser cladding experiment are as follows: the laser power is 2000 W, powder feed rate 20 g × min-1, the scanning speed 4 mm × s-1. The cladding layer and the substrate exhibit good metallurgical bonding under the above processing parameters. The microstructure of the cladding layer is fine, the dilution rate is 9.8 wt.-%, and the microhardness of the cladding layer is 710.7 HV.

Parameter optimisation of laser cladding repair for an Invar alloy mould

2018 ◽  
Vol 233 (8) ◽  
pp. 1859-1871 ◽  
Author(s):  
Shichao Zhu ◽  
Wenliang Chen ◽  
Xiaohong Zhan ◽  
Liping Ding ◽  
Junjie Zhou
Keyword(s):  
Dilution Rate ◽  
Laser Cladding ◽  
Laser Power ◽  
Scanning Speed ◽  
Advanced Technology ◽  
Invar Alloy ◽  
Geometric Features ◽  
Feeding Rates ◽  
Cladding Layer ◽  
Powder Feeding

Laser cladding repair is an advanced technology for repairing Invar alloy moulds; however, the influences of various processing parameters on the quality of the Invar alloy moulds have yet to be determined. To explore the optimisation of laser cladding repair parameters, analyses of the geometric features and microstructure of the cladding layer were conducted. First, the influences of different powder feeding rates and scanning speeds on the dilution rate of the substrate were investigated by establishing a mathematical model of the laser power attenuation. Next, the influences of the parameters on the geometric features of the cladding layer were analysed. Finally, the influences of the parameters on the microstructure of the cladding layer were evaluated. At a laser power of 2300 W, a scanning speed of 3 m/min, and a powder feeding rate of 9 g/min, the best results of the width, height, dilution rate, roughness, and contact angle of the cladding layer were obtained. The results of this study indicated that excellent metallurgical bonding occurred between the cladding layer and the interface layer, and that the intended geometric features and desired microstructure of the cladding layer were obtained.

Processing parameter, microstructure and hardness of Ni base intermetallic alloy coating fabricated by laser cladding

MRS Advances ◽  
2017 ◽  
Vol 2 (26) ◽  
pp. 1381-1386 ◽  
Author(s):  
Takeshi Okuno ◽  
Yasuyuki Kaneno ◽  
Takuto Yamaguchi ◽  
Takayuki Takasugi ◽  
Satoshi Semboshi ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Feed Rate ◽  
Laser Power ◽  
Alloy Coating ◽  
Intermetallic Alloy ◽  
Ingot Metallurgy ◽  
Processing Parameter ◽  
Powder Feed Rate ◽  
Cladding Layer ◽  
Powder Feed

ABSTRACTNi base intermetallic alloy coating was fabricated by laser cladding, controlling the laser power and powder feed rate. Atomized powder of the Ni base intermetallic alloy was laser-cladded on the substrate of stainless steel 304. The hardness and microstructure of the clad layers were investigated by Vickers hardness test, SEM, XRD and TEM observations. The hardness of the cladding layer was affected by the dilution with the substrate; it increased with decreasing laser power and increasing powder feed rate. By optimizing the dilution with the substrate, the cladding layer with an almost identical hardness level to that of the Ni base intermetallic alloy fabricated by ingot metallurgy was obtained. The TEM observations revealed that a very fine-sized microstructure composed of Ni3Al and Ni3V was partially formed even in the as-cladded state. After annealing, the two-phase microstructure composed of Ni3Al and Ni3V was developed in the cladding layer, resulting in enhanced hardness in the cladding layers fabricated in the majority of cladding conditions.

Laser power and scanning speed influence on the microstructure, hardness, and slurry erosion performance of Colmonoy-5 claddings

2020 ◽  
Vol 234 (7) ◽  
pp. 947-961
Author(s):  
T Savanth ◽  
Jastej Singh ◽  
JS Gill
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Laser Processing ◽  
Laser Power ◽  
Erosive Wear ◽  
Scanning Speed ◽  
Processing Parameters ◽  
X Ray ◽  
High Scanning Speed ◽  
Scanning Electron

A 4kW Yb: YAG solid-state disc laser, with a four-way co-axial cladding head with powder feeding technique was employed to fabricate single-layer clads of Ni-based hardfacing alloy (Colmonoy-5) on medium carbon steel (ASME SA105) substrate by varying the laser processing parameters namely, beam power level (designated as low: 1200 W, medium: 1400 W, and high: 1600 W) and scanning speed (designated as low: 300 mm/min, medium: 400 mm/min, and high: 500mm/min). The laser clads were evaluated for their microstructural characteristics, microhardness, and slurry erosive wear performance with an aim to understand the effect of process parametric variations on their properties. Microstructural analyses of the clads were carried out using an optical microscope and a field-emission scanning electron microscope with attached energy-dispersive X-ray spectrometer supplemented by their Vickers microhardness testing and X-ray diffraction examination. The variation in laser processing parameters exerted a strong influence on the microstructural features of the clads in terms of γ-Ni dendrite size as well as morphology and distribution of various complex precipitates such as Cr-carbides and borides with relatively uniform distribution observed for the clads corresponding to low laser power and high scanning speed. The variation in laser power had relatively a greater influence on microhardness than the scanning speed variation. Micro-cutting, plastic deformation, crater formation besides ploughing away of the softer matrix were the typical fracture features associated with slurry eroded clads when examined under field-emission scanning electron microscope. Results of the slurry erosive wear tests showed that the clads pertaining to low laser power and high scanning speed exhibited superior wear resistance as compared to their counterparts.

scholarly journals Geometry Analysis and Microhardness Prediction of Nickel-Based Laser Cladding Layer on the Surface of H13 Steel

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 408
Author(s):  
Fangping Yao ◽  
Lijin Fang ◽  
Xiang Chen
Keyword(s):  
Laser Cladding ◽  
Laser Power ◽  
Polynomial Regression ◽  
Scanning Speed ◽  
Processing Parameters ◽  
H13 Steel ◽  
Cladding Layer ◽  
Geometry Analysis ◽  
The Relationship ◽  
Powder Feeding

In order to improve the resistance to thermal fatigue and wear resistance of H13 hot-working tool steel, a nickel-based composite coating was prepared on its surface by laser cladding technology. The relationship was studied between the main processing parameters and the size of the cladding layer such as height and width. Based on the orthogonal polynomial regression method, the relationships were modeled mathematically between laser power, scanning speed, powder feeding voltage and microhardness. This model was proved to be able to predict the laser power and powder feeding voltage under 1100 Hv microhardness.

Study on the Laser Alloy Cladding for Re-Manufacturing of the Surface of 40Cr

2015 ◽  
Vol 713-715 ◽  
pp. 2900-2904
Author(s):  
Yan Li Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Process Parameters ◽  
Laser Power ◽  
Scanning Speed ◽  
Laser Alloy ◽  
Hardness Tester ◽  
Cladding Layer ◽  
Cladding Layers ◽  
Scanning Electron

The laser alloy cladding technology is used to treat the surface of 40Cr, and the two alloy powders are used separately. The process parameters are different, such as laser power, feed rate and scanning speed etc. The microstructure and hardness of cladding layers are analyzed by using scanning electron microscope and hardness tester. Generally, the surface quality is improved apparently. Under the similar laser power and powder quantity, the thickness of Ni60 cladding layer is much larger than Fe60. The hardness of Ni60 layer and Fe60 layer are all higher than substrate. There are more cracks in Ni60 layer than in Fe60 layer. The parameters of sample No.1 is optimal.

scholarly journals Laser Additive Remanufacturing Parameters Optimization and Experimental Study of Heavy-Duty Sprocket

2021 ◽  
Author(s):  
Chenguang Guo ◽  
Ning Lv ◽  
Haitao Yue ◽  
Qiang Li ◽  
Jianzhuo Zhang
Keyword(s):  
Dilution Rate ◽  
Process Parameters ◽  
Feeding Rate ◽  
Scanning Speed ◽  
Heavy Duty ◽  
Geometric Characteristics ◽  
Cladding Layer ◽  
Melting Area ◽  
Good Prediction Accuracy ◽  
Powder Feeding

Abstract Experimental research on laser additive remanufacturing technology of heavy-duty sprocket was carried out. The influences of laser power, scanning speed and powder feeding rate on cladding height, cladding area, melting area and dilution rate were compared and analyzed. The prediction models of the combination of process parameters with the geometric characteristics of cladding layer and dilution were established. A multi-objective process parameter optimization model with the maximum cladding height and cladding area maximum, the minimum melting area and dilution rate as objective functions was established, and the model was optimized and solved based on MOPSO algorithm. The laser additive remanufacturing repairing experiment of damaged sprocket was carried out by using the optimal parameters combination, and the microstructure and mechanical properties of the repaired region were analyzed. The results show that the scanning speed and powder feeding rate are the main factors influencing the geometric characteristics and dilution of the cladding area, and the models have good prediction accuracy. The optimal process parameters (1150 W, 950 mm/min, 3.8 rad/min) obtained by MOPSO algorithm is adopted to repair the damaged sprocket. The repaired area without cracks and pores, the cladding layer shows good metallurgical bonding with the substrate and the microhardness is twice that of the substrate. The experimental results prove that the laser additive remanufacturing technology is feasible to repair the damaged heavy-duty sprocket and has a strong engineering application prospect.

Optimization of built-part distortion in laser powder bed fusion processing of Inconel 718

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
You-Cheng Chang ◽  
Hong-Chuong Tran ◽  
Yu-Lung Lo
Keyword(s):  
Cooling Rate ◽  
Cantilever Beam ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Powder Bed Fusion ◽  
Simulation Framework ◽  
Content Type ◽  
Powder Bed ◽  
Simulation Results

Purpose Laser powder bed fusion (LPBF) provides the means to produce unique components with almost no restriction on geometry in an extremely short time. However, the high-temperature gradient and high cooling rate produced during the fabrication process result in residual stress, which may prompt part warpage, cracks or even baseplate separation. Accordingly, an appropriate selection of the LPBF processing parameters is essential to ensure the quality of the built part. This study, thus, aims to develop an integrated simulation framework consisting of a single-track heat transfer model and a modified inherent shrinkage method model for predicting the curvature of an Inconel 718 cantilever beam produced using the LPBF process. Design/methodology/approach The simulation results for the curvature of the cantilever beam are calibrated via a comparison with the experimental observations. It is shown that the calibration factor required to drive the simulation results toward the experimental measurements has the same value for all settings of the laser power and scanning speed. Representative combinations of the laser power and scanning speed are, thus, chosen using the circle packing design method and supplied as inputs to the validated simulation framework to predict the corresponding cantilever beam curvature and density. The simulation results are then used to train artificial neural network models to predict the curvature and solid cooling rate of the cantilever beam for any combination of the laser power and scanning speed within the input design space. The resulting processing maps are screened in accordance with three quality criteria, namely, the part density, the radius of curvature and the solid cooling rate, to determine the optimal processing parameters for the LPBF process. Findings It is shown that the parameters lying within the optimal region of the processing map reduce the curvature of the cantilever beam by 17.9% and improve the density by as much as 99.97%. Originality/value The present study proposes a computational framework, which could find the parameters that not only yield the lowest distortion but also produce fully dense components in the LPBF process.

Characteristics of Ni–Cr–Fe laser clad layers on EA4T steel

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744031
Author(s):  
Wenjing Chen ◽  
Hui Chen ◽  
Yongjing Wang ◽  
Congchen Li ◽  
Xiaoli Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
The Matrix ◽  
Feeding Speed ◽  
Upper Bainite ◽  
Scanning Electron

The Ni–Cr–Fe metal powder was deposited on EA4T steel by laser cladding technology. The microstructure and chemical composition of the cladding layer were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The bonding ability between the cladding layer and the matrix was measured. The results showed that the bonding between the cladding layer and the EA4T steel was metallurgical bonding. The microstructure of cladding layer was composed of planar crystals, columnar crystals and dendrite, which consisted of Cr2Ni3, [Formula: see text] phase, M[Formula: see text]C6 and Ni3B phases. When the powder feeding speed reached 4 g/min, the upper bainite occurred in the heat affected zone (HAZ). Moreover, the tensile strength of the joint increased, while the yield strength and the ductility decreased.

scholarly journals Optimization of laser cladding process for additive repair of high temperature and high pressure valve sealing surface

2019 ◽  
Author(s):  
Lei Che
Keyword(s):  
High Pressure ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Laser Cladding ◽  
Laser Power ◽  
Feeding Rate ◽  
Scanning Speed ◽  
Alloy Layer ◽  
Laser Cladding Process ◽  
Valve Sealing

Laser cladding technology is highly suitable for the remanufacturing of thin-walled and easily deformable parts due to its concentrated energy density. Due to the high temperature and high pressure corrosion environment, the valve sealing surface is prone to corrosion, wear and other failures. A nickel-based tungsten carbide alloy layer was prepared on the valve sealing surface substrate material by laser cladding process. By designing orthogonal experiments, the effects of laser power (P), scanning speed (Vb), powder feeding rate (Vf), and WC content (wt%) on the alloy layer were investigated. A fuzzy comprehensive evaluation method including macroscopic quality, microstructure, microhardness, anti-wear performance, oxidation resistance, compactness and corrosion resistance was proposed. The experimental results showed that the hardness, oxidation resistance and corrosion resistance of the laser alloy layer are significantly improved compared with the matrix; the optimum process parameters and the addition ratio of WC powder are laser power (P) of 1.1 kW and scanning speed (Vb) of 800 mm/min. The powder feeding rate (Vf) was 20%, and the WC content was 20% by weight.

Effect of Laser Processing Parameters on Microhole Quality of Aluminium Nitride Ceramics

2021 ◽  
Vol 871 ◽  
pp. 277-283
Author(s):  
Chun Yan Yang ◽  
Yun Hao ◽  
Bozhe Wang ◽  
Hai Yuan ◽  
Liu Hui Li
Keyword(s):  
Laser Processing ◽  
Laser Power ◽  
Picosecond Laser ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Recast Layer ◽  
Aluminium Nitride ◽  
Obvious Effect ◽  
Nitride Ceramics

A picosecond laser in spin-cutting mode was used to drill 500μm diameter microholes on 150μm thick aluminium nitride ceramic. The effects of laser processing parameters such as the laser power, scanning speed, and defocus amount on the microhole quality were studied. The results show that as the laser power increases, the inlet and outlet diameters of the holes increase, the taper decreases slightly, and the thickness of the recast layer decreases evidently. The scanning speed has no obvious effect on the diameter and taper of the hole; however, the hole can not be drilled through when the speed is too large. Positive defocus can effectively reduce the taper of the hole. Under 28.5W laser power, 400Hz frequency, 200mm/s scanning speed, and zero defocus amount conditions, high-quality microholes with a taper of 0.85° were obtained.

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