Effect of Cooling Modes on Microstructure and Mechanical Properties of Cr18Ni8Mo2Si Cladding to 40Cr by Laser Cladding Technology

2019 ◽  
Author(s):  
Mingsan Xu ◽  
Simo Liu ◽  
Mingliang Mei ◽  
Bingbing Li
Keyword(s):  
Residual Stress ◽  
Laser Cladding ◽  
Temperature Control ◽  
New Technology ◽  
Scanning Speed ◽  
Structural Defects ◽  
Metallic Material ◽  
Orthogonal Experiments ◽  
Bonding Effect ◽  
Preheating Temperature

Abstract Laser cladding is a new technology to clad metallic material to substrate. The objective of this research is to find optimized process parameters such as preheating temperature of substrate, laser power, scanning speed, spot diameter for cladding Cr18Ni8Mo2Si on 40Cr substrate. Moreover, effects of different cooling modes, cooling in temperature control box or natural environment were studied. Orthogonal experiments are used to find optimized parameters and better cooling strategy. Experimental results are analyzed through measurements of residual stress, micro-hardness, and metallic microstructure. It was observed that parts cooling in temperature control box show better qualities: smaller residual stress, less cracks or other structural defects, better microstructure, and better bonding effect. This research provides a guideline for further researches in temperature control of laser cladding and expands application to rotary die cutting machine.

Research on the Fabrication of Bioceramic Composite Coatings Fabricated by Nd-YAG Laser Cladding

2015 ◽  
Vol 723 ◽  
pp. 852-855
Author(s):  
Ying Chun Wang ◽  
Xiang Fei Lv ◽  
Deng Jie Zhu ◽  
Shao Min Qu
Keyword(s):  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
New Technology ◽  
Scanning Speed ◽  
Processing Technique ◽  
Yag Laser ◽  
Cladding Layer ◽  
Ti6al4v Substrate ◽  
Average Grain Size

Laser surface cladding is a material processing technique to overlay the precursor material with the substrate to form a sound chemical and metallurgical bonding. Recently, laser cladding technique has been introduced in the bioceramic coating field. This paper presents a new technology to obtain bioceramic composite coating on Ti6Al4V substrate by Nd-YAG laser cladding. The microstructures of the mixed powders and cladding layer were investigated by scanning electron microscopy, and the compositions were analyzed by electron diffraction spectroscopy. The phases of the mixed powders and cladding layer were clarified by X-ray diffraction technology. Composite coating including HAP,Ca2P2O7,Ca3(PO4)2 and calcium titanates was successfully obtained by Nd-YAG laser cladding with pre-depositing mixed powders of CaHPO4·2H2O and CaCO3 directly on Ti6Al4V substrate. The average grain size of the mixed powders is 3μm from the image analyse software. The most important parameter that affected the completion of laser cladding was the scanning speed.

Influence of Preheating Temperature on Mechanical Properties of Laser Cladding Layer

2016 ◽  
Author(s):  
Jibin Jiang ◽  
Guofu Lian ◽  
Mingsan Xu ◽  
Chunyu Li ◽  
Bingsan Chen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Laser Cladding ◽  
Heat Affected Zone ◽  
Processing Parameters ◽  
Cladding Layer ◽  
Laser Cladding Process ◽  
Preheating Temperature ◽  
Substrate Preheating ◽  
Physical And Chemical ◽  
Cladding Layers

Physical and chemical changes always occur in the process of laser cladding, and the cladding quality is directly affected by processing parameters. This paper mainly focused on effects of temperature field of preheating substrate on the cladding quality. Laser cladding process has the following experimental parameters: laser power, powder feeding rate and rotational speed. Three types of cladding powders were used: Ni60A, Cr12MoV and WC-Co. Experiments were conducted by using different substrate preheating temperatures and cladding materials, which affect the quality of cladding layers. Comparison and analysis of the three types of powders showed that under different preheating temperatures, the cladding layer is mainly affected by tensile stress. Besides that, the residual stress of cladding layer is always higher than that of heat affected zone and substrates. The best preheating temperature to test the residual stress for three types of powders are: 600°C, 400°C and 300°C. For all three types of powders under different preheating temperatures, cladding layer and substrate have compact and uniform structures. However, when substrate is overheated the cracking will occur in the substrate. Under different preheating temperatures, the Vickers hardness is higher than that of heat affected zone and the substrate for all three materials. The preheating temperatures for getting the maximum hardness are respectively 300°C, 600°C and 400°C.

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

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2401 ◽  
Author(s):  
Chenggang Ding ◽  
Xu Cui ◽  
Jianqiang Jiao ◽  
Ping Zhu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Laser Cladding ◽  
Nuclear Power ◽  
Steel Substrate ◽  
Residual Deformation ◽  
Deposition Technique ◽  
Analysis Model ◽  
Preheating Temperature ◽  
Uneven Heating

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 significance 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 field 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 finite 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 finite 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.

Simulation of Residual Stress in Lens Deposited H13 Tool Steel on Copper Substrate

2011 ◽  
Author(s):  
Tushar K. Talukdar ◽  
Liang Wang ◽  
Sergio D. Felicelli
Keyword(s):  
Residual Stress ◽  
Tool Steel ◽  
Laser Power ◽  
Copper Substrate ◽  
Scanning Speed ◽  
Temperature History ◽  
H13 Tool Steel ◽  
Scanning Strategies ◽  
Stress Accumulation ◽  
Free Edges

Solidification cracking represents a significant scientific and technical challenge in the rapid fabrication of bimetallic parts involving Cu and H13 tool steel. The main cause of the cracking formation is attributed to the residual stress accumulation, which depends on the thermal history and phase transformation during the deposition. In this research, a thermomechanical three-dimensional finite element model is developed to determine the temperature history and residual stress in Cu-H13 samples deposited by the Laser Engineered Net Shaping (LENS) process. The development of the model was carried out using the SYSWELD software package. The metallurgical transformations are taken into account using the temperature dependent material properties and the continuous cooling transformation diagram. Two different scanning strategies — alternative and unidirectional — are studied. The same model is also applied to a H13-H13 sample to compare the results. The input laser power is optimized for each layer and three different scanning speeds to maintain a steady molten pool size. It is observed that for a constant scanning speed the required laser power decreases with addition of more layers, and with the increase of scanning speed the laser power needs to be increased. The residual stress is found to be compressive near the center of the deposited wall and tensile at the free edges, which is consistent with the published experimental results in the literature. Similar stress distributions are obtained for both scanning strategies with higher stress concentration at the free edges of the interface between the substrate and the first layer. In these regions, the use of H13 substrate results in a higher stress accumulation than the Cu substrate.

Microstructure and Hardness of the ZrO2/Ni60A Composite Coating Formed by Feeding Powder Laser-Clad on Circular Surface

2011 ◽  
Vol 138-139 ◽  
pp. 732-736
Author(s):  
Ba Sheng Ouyang ◽  
Run Juan You
Keyword(s):  
Laser Cladding ◽  
Ceramic Powder ◽  
Scanning Speed ◽  
Micro Hardness ◽  
Processing Property ◽  
Laser Process ◽  
Cladding Layer ◽  
Parameter Variations ◽  
Circular Surface ◽  
Cladding Layers

Cladding experiment with parameter variations was presented to manufacture the better processing property coating by laser cladding self-fused Ni-based ceramic powder of ZrO2 composite on the excircle surface of 304 SUS. The influence of the laser process parameters on macroscopic view, microstructure and micro-hardness of the laser cladding layers were investigated. The results show that we can get better coating when laser power is 1.5KW, and that the cladding layer microstructure has the trend of refined framework with the growing of scanning speed; micro-hardness will be higher and distribution from substratum to surface with little fluctuate by optimizing scanning speed.

Friction wear property of laser surface processed Ni-based amorphous alloy coatings

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940014
Author(s):  
Ruifeng Li ◽  
Yi Qiu ◽  
Yanyan Zhu
Keyword(s):  
Amorphous Alloy ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Wear Behavior ◽  
Testing Machine ◽  
Scanning Speed ◽  
Nominal Composition ◽  
Wear Property ◽  
Laser Remelting ◽  
Wear Tests

A Ni–Fe–B–Si–Nb amorphous alloy was deposited on a steel substrate surface via a laser cladding process, and a laser cladding plus laser remelting process. The wear behavior of the laser processed samples and the bulk metallic glass (BMG) sample with the same nominal composition were tested using a pin-on-disc type testing machine. The nano-mechanical properties of the samples were measured with a nano-characterization system. The friction wear tests showed that deep grooves and wear debris were formed on the worn surface of the laser cladded coating, while only shallow grooves for the laser remelted coatings. The friction coefficients of laser remelted coatings and BMG were lower than the laser cladded coating. The wear mass losses of the laser remelted coating were less than the BMG when the laser remelting scanning speed was higher than 6 mm/min. The nano-hardness and elastic modulus of the remelted coating is higher than that of the laser cladded coating. Also, they increase with the increasing laser scanning speed with 1227.9 HV and 277.4 GPa when the remelting scanning speed is 8 m/min. Based on the nano-indentation and friction wear tests results, it was found that the friction wear properties of the laser cladded coating, laser remelted coatings and BMG related well to the ratio of H3/E2. A higher value of H3/E2 can lead to a better wear resistance property.

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.

scholarly journals Effect of Process Parameters and High-Temperature Preheating on Residual Stress and Relative Density of Ti6Al4V Processed by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 930 ◽  
Author(s):  
Martin Malý ◽  
Christian Höller ◽  
Mateusz Skalon ◽  
Benjamin Meier ◽  
Daniel Koutný ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Residual Stresses ◽  
Relative Density ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Stress Reduction ◽  
Laser Melting ◽  
Preheating Temperature ◽  
Laser Velocity

The aim of this study is to observe the effect of process parameters on residual stresses and relative density of Ti6Al4V samples produced by Selective Laser Melting. The investigated parameters were hatch laser power, hatch laser velocity, border laser velocity, high-temperature preheating and time delay. Residual stresses were evaluated by the bridge curvature method and relative density by the optical method. The effect of the observed process parameters was estimated by the design of experiment and surface response methods. It was found that for an effective residual stress reduction, the high preheating temperature was the most significant parameter. High preheating temperature also increased the relative density but caused changes in the chemical composition of Ti6Al4V unmelted powder. Chemical analysis proved that after one build job with high preheating temperature, oxygen and hydrogen content exceeded the ASTM B348 limits for Grade 5 titanium.

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.

Experimental Study of Forming Rene95 Alloy Parts by Laser Cladding

2001 ◽  
Author(s):  
Qilin Deng ◽  
Dejin Hu ◽  
Jingyu Pei ◽  
Wenwu Zhang ◽  
Y. Lawrence Yao
Keyword(s):  
Experimental Study ◽  
Laser Cladding ◽  
Laser Power ◽  
Alloy Powder ◽  
High Strength ◽  
Scanning Speed ◽  
Main Process ◽  
Beam Diameter ◽  
Laser Beam Diameter ◽  
Metal Parts

Abstract In this paper, experimental study of forming metal parts by laser cladding Rene95 alloy powder was reported. The influence of main process parameters, such as laser power, scanning speed and laser beam diameter, on the thickness, width and the angle of the laser cladding track was investigated. The microstructures of laser cladding parts were studied and compared with those of common casting parts. The obtained Rene95 metal parts formed by laser cladding are dense and of high strength.

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