Transient Temperature Field Analysis in Laser Cladding Processing

2012 ◽  
Vol 538-541 ◽  
pp. 1874-1877 ◽  
Author(s):  
Shuai Zhang ◽  
Yan Ling Tian ◽  
Fu Jun Wang

A 3-dimensional (3D) thermal distribution computational methodology for laser cladding is presented. Based on the developed model, which considers the latent heat and change of conductivity in different phase, the transient temperature fields for the preplaced laser cladding processing are performed. The effect of processing parameters including laser power, scanning speed and laser spot diameter on melt pool temperature filed was extensively discussed and some conclusions were drawn.

2014 ◽  
Vol 6 ◽  
pp. 217584 ◽  
Author(s):  
J. Schilp ◽  
C. Seidel ◽  
H. Krauss ◽  
J. Weirather

Process monitoring and modelling can contribute to fostering the industrial relevance of additive manufacturing. Process related temperature gradients and thermal inhomogeneities cause residual stresses, and distortions and influence the microstructure. Variations in wall thickness can cause heat accumulations. These occur predominantly in filigree part areas and can be detected by utilizing off-axis thermographic monitoring during the manufacturing process. In addition, numerical simulation models on the scale of whole parts can enable an analysis of temperature fields upstream to the build process. In a microscale domain, modelling of several exposed single hatches allows temperature investigations at a high spatial and temporal resolution. Within this paper, FEM-based micro- and macroscale modelling approaches as well as an experimental setup for thermographic monitoring are introduced. By discussing and comparing experimental data with simulation results in terms of temperature distributions both the potential of numerical approaches and the complexity of determining suitable computation time efficient process models are demonstrated. This paper contributes to the vision of adjusting the transient temperature field during manufacturing in order to improve the resulting part's quality by simulation based process design upstream to the build process and the inline process monitoring.


1995 ◽  
Vol 11 (02) ◽  
pp. 102-110 ◽  
Author(s):  
Jon J. Yagla ◽  
Richard S. Haag ◽  
Matthew E. Scott

A "seamless engineering" approach for mechanical design and laser welding manufacturing combines a method for welding analysis with a method for stress analysis through the development of radiant heating models for use in a nonlinear finite-element computer program. Experiments were performed welding steel plates, using a five-axis computer numerical controlled (CNC) workstation to translate welding specimens under a 5-kW CO2 (carbon dioxide) laser. Thermocouples installed near the weld seam were used to measure the transient temperature field during welding. The measured temperatures were compared with the analytical predictions, and the welds were sectioned so that predictions of properties in the heat-affected zone could be compared with experimental data. This paper presents analytical results using classical methods of analysis and includes solutions for temperature fields, heating and cooling rates, and metallurgical properties in heat-affected zones.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4849
Author(s):  
T. Minasyan ◽  
S. Aydinyan ◽  
E. Toyserkani ◽  
I. Hussainova

Mo(Si1−x,Alx)2 composites were produced by a pulsed laser reactive selective laser melting of MoSi2 and 30 wt.% AlSi10Mg powder mixture. The parametric study, altering the laser power between 100 and 300 W and scan speed between 400 and 1500 mm·s−1, has been conducted to estimate the effect of processing parameters on printed coupon samples’ quality. It was shown that samples prepared at 150–200 W laser power and 400–500 mm·s−1 scan speed, as well as 250 W laser power along with 700 mm·s−1 scan speed, provide a relatively good surface finish with 6.5 ± 0.5 µm–10.3 ± 0.8 µm roughness at the top of coupons, and 9.3 ± 0.7 µm–13.2 ± 1.1 µm side surface roughness in addition to a remarkable chemical and microstructural homogeneity. An increase in the laser power and a decrease in the scan speed led to an apparent improvement in the densification behavior resulting in printed coupons of up to 99.8% relative density and hardness of ~600 HV1 or ~560 HV5. The printed parts are composed of epitaxially grown columnar dendritic melt pool cores and coarser dendrites beyond the morphological transition zone in overlapped regions. An increase in the scanning speed at a fixed laser power and a decrease in the power at a fixed scan speed prohibited the complete single displacement reaction between MoSi2 and aluminum, leading to unreacted MoSi2 and Al lean hexagonal Mo(Si1−x,Alx)2 phase.


2011 ◽  
Vol 686 ◽  
pp. 646-653 ◽  
Author(s):  
Jing Liang ◽  
Sui Yuan Chen ◽  
Chang Sheng Liu ◽  
Feng Hua Liu

Two kinds of mixed powders:Ti-6Al-4V/B/C and Ti-6Al-4V/B4C which are pre-pasted or synchronized fed on Ti-6Al-4V substrates separately were scanned by a 500W pulsed YAG laser to induce in situ formation of titanium composite coatings contained TiBxand TiC ceramic reinforced phases. The influences of laser processing parameters including Pulse Frequency (PF), Pulse Width (PW), Laser Power (P) and Scanning Speed (V) together with the powder proportions on the microstructure and properties of the coatings were investigated. Microstructures, phase components of the coating were analyzed by OM, SEM, TEM and XRD respectively. Experimental results show that two and more kinds of ceramic reinforcements were in situ formatted in the matrix of Ti-6Al-4V. TiB and TiC ceramics were formed evenly with the morphology of needle, tiny dendrites and disperse particles in the prepasted single path specimens. For the powder feed laser cladding layers, the ceramic reinforcements were TiB (needlelike), TiB2(hexagonal prism or rodlike), a small amount of TiC (disperse particles) and non fully reacted B4C. The microhardness increased with the increase of the amount of B4C and B+C additions. When the added B and C contents are the same, the microhardness of the coating with B4C addition is higher than that of the coating with B+C addition. The average micro-hardness of a powder prepasted (with 20 wt.% B4C addition) multi-path laser cladding layer formed under the optimized processing parameters is up to 800HV, which is more than 2 times of that of the substrate (340Hv), and the wear weight loss of the layer decreased nearly 3 times that of the substrate.


2021 ◽  
Vol 233 ◽  
pp. 04046
Author(s):  
Changhao Zhang ◽  
Hu Li ◽  
Jianyu Yang ◽  
Huawei Lu ◽  
Peng Su

According to the structural characteristics of thin-walled parts, a model slicing method is proposed, and its mathematical process is established. The three-dimensional transient temperature field in the process of synchronous powder feeding laser cladding is studied and verified by numerical simulation method, and the thin-walled parts formed by later experimental processing are processed by the results of numerical simulation. Using the simulation results of temperature field as the basis for optimizing the processing parameters, the forming path of thin-walled parts is programmed and optimized, and the experimental verification shows the reliability of this method.


2019 ◽  
Vol 813 ◽  
pp. 185-190 ◽  
Author(s):  
Fazati Bourahima ◽  
Anne Laure Helbert ◽  
Vincent Ji ◽  
Michel Rege ◽  
Arnaud Courteaux ◽  
...  

In glass industry, laser cladding is an innovative surfacing technique allowing to deposit a layer of nickel to protect glass mold against corrosion, abrasion and thermal fatigue. This method (powder fusion by projection), well known in additive manufacturing represents a real technological leap for the glass industry. But during laser cladding of Ni-based powder on gray cast iron, cracks can be observed for some process conditions. These cracks are often due to the Heat Affected Zone that creates structural stresses linked to the development of a martensitic structure in the ferritic matrix of the lamellar graphite cast iron. The aim of this work is to observe the impact of laser cladding (without substrate pre-heating usually employed to limit cracking) on the coating behavior but also on the flake-graphite cast iron substrates. The microstructure and the mechanical properties were studied (SEM and microanalysis, microhardness) around the interface cladding/substrate. Also, the impact of the processing parameters (power P (1500-2300 W), scanning speed v (2.5-10 mm/s) and powder feeding rate PFR (24.5-32.5 g/min) was studied by using the ANOVA (ANalysis Of VAriance) technique. It has been observed that laser cladding on graphite cast iron is possible without cracks by limiting the linear energy induced by the process. Also, an optimization of the processing parameters (P, v, PFR) in order to obtain the industrial expected geometry of the coating has been proposed.


2011 ◽  
Vol 80-81 ◽  
pp. 46-50
Author(s):  
Qing Ming Chang ◽  
Chang Jun Chen ◽  
Xia Chen ◽  
Si Qian Bao ◽  
Chen Gang Pan

A 3-D modeling based on the numerical resolution of fluid flow and heat transfer for laser-cladding processes of In718 Superalloy is proposed. The implementation of developed procedures allowed us to treat the problem with specific and complex boundary conditions. The applied loading is a moving heat source that depends on process parameters such as power density, laser beam diameter and scanning speed. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. The computational results present good coincidences with the corresponding experiments of laser cladding process.


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