scholarly journals Research on Heat Source Model and Weld Profile for Fiber Laser Welding of A304 Stainless Steel Thin Sheet

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Peizhi Li ◽  
Yu Fan ◽  
Chonghao Zhang ◽  
Zhiyuan Zhu ◽  
Wenteng Tian ◽  
...  

A heat source model is the key issue for laser welding simulation. The Gaussian heat source model is not suitable to match the actual laser weld profile accurately. Furthermore, fiber lasers are widely recognized to result in good-quality laser beam output, a narrower weld zone, less distortion, and high process efficiency, compared with other types of lasers (such as CO2, Nd : YAG, and diode lasers). At present, there are few heat source models for fiber laser welding. Most of researchers evaluate the weld profile only by the bead width and depth of penetration, which is not suitable for the laser keyhole welding nail-like profile. This paper reports an experimental study and FEA simulation of fiber laser butt welding on 1 mm thick A304 stainless steel. A new heat source model (cylindrical and cylindrical) is established to match the actual weld profile using Marc and Fortran software. Four bead geometry parameters (penetration depth, bead width, waist width, and depth of the waist) are used to compare between the experimental and simulation results. The results show that the heat source model of cylindrical and cylindrical can match the actual shape of the fiber laser welding feasibly. The error range of the penetration depth, bead width, waist width, and depth of the waist between experimental and simulation results is about 4.1 ± 1.6%, 2.9 ± 2.0%, 13.6 ± 7.4/%, and 18.3 ± 8.0%, respectively. In addition, it is found that the depth of penetration is more sensitive to laser power rather than bead width, waist width, and depth of the waist. Welding speed has a similar influence on the depth of penetration, weld width, waist width, and depth of the waist.

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2188
Author(s):  
Changmin Pyo ◽  
Jaewoong Kim ◽  
Du-Song Kim

Due to various environmental regulations, the demand for natural gas, i.e., a clean energy, is expected to increase continuously. In terms of efficient storage and transportation of natural gas, liquefied natural gas has an advantageous volume of 1/600 compared to natural gas, but the materials that can be used at a cryogenic temperature of −163 °C are limited. A 9% nickel steel is a material recommended by IMO through IGC. It has excellent mechanical properties compared to other cryogenic materials, but its use has been limited due to its disadvantages in arc welding. Therefore, the main topic of this study is the automatic welding of 9% nickel steel using fiber laser and its purpose is to predict the welding deformation during fiber laser welding. First, an investigation was conducted to find the fiber laser welding heat source. A model that can cover all the models in prior studies such as curve, exponential, conical, conical-conical combination, and conical-cylinder combination models was proposed and the heat source model was constructed in a multi-layer format. Heat transfer analysis was performed using the ratio of a heat source radius and heat energy of each layer as a variable and the pass or failure of a heat source was determined by comparing the analysis results to the experimental results. By changing the variables in conjunction with the optimization algorithm, the main parameters of a passed heat source model were verified in a short period of time. In addition, the tendency of parameters according to the welding speed was checked.


2013 ◽  
Vol 31 (4) ◽  
pp. 82s-85s ◽  
Author(s):  
Rittichai Phaonaim ◽  
Masayuki Yamamoto ◽  
Kenji Shinozaki ◽  
Motomichi Yamamoto ◽  
Kota Kadoi

Author(s):  
Samuel Lorin ◽  
Julia Madrid ◽  
Rikard Söderberg ◽  
Kristina Wärmefjord

Abstract Laser welding is a common technique for joining metals in many manufacturing industries. Due to the heat input and the resulting melting and solidification, the parts deform causing residual distortion and residual stresses. To assure the geometrical and functional quality of the product, Computational Welding Mechanics (CWM) is often employed in the design phase to predict the outcome of different design proposals. Furthermore, CWM can be used to design the welding process with the objective of assuring the quality of the weld. However, welding is a complex multi-physical process and in a design process it is typically not feasible, for example, to employ fluid simulation of the weld pool in order to predict deformation, especially if a set of design proposals is under investigation. Instead, what is used is a heat source that emulates the heat input from the melt pool. However, standard heat sources are typically not flexible enough to capture the fusion zone for deep keyhole mode laser welding. In this paper, a new heat source model for keyhole mode laser welding is presented. In an industrial case study, a number of bead on plate welds have been employed to compare standard weld heat sources and develop the new heat source model. The proposed heat source is based on a combination of standard heat sources. From the study, it was concluded that the standard heat sources could not predict the observed melted zone for certain industrial application while the new heat source was able to do so.


Author(s):  
Yu Shi ◽  
Rihong Han ◽  
Jiankang Huang ◽  
Shao Yan

Based on the features of double electrode gas metal arc welding (DE-GMAW), a new hybrid heat-source model for DE-GMAW was proposed. Using this heat-source model, the temperature fields of DE-GMAW with different welding parameters were simulated. According to the simulation results with different welding parameters, the influence of welding parameters to the heat input to base metal in DE-GMAW were analyzed. To verify the rationality of the hybrid heat-source model of DE-GMAW, the simulation results of the temperature field were compared with the experimental results with same welding parameters. The research results indicate that under the same total current, the heat input to base metal decrease gradually with the increase of by-pass current. In addition, the closer to the welding line from the measured point the greater decrease rate of the heat input to base metal. By the study and comparison of the thermal cycle curve of measured points, the simulation results were in good agreement with the experimental results. These results indicate that the calculated temperature field is accurate and the hybrid heat-source model is rational.


2011 ◽  
Vol 121-126 ◽  
pp. 3347-3351 ◽  
Author(s):  
Hong Xiao Wang ◽  
Chun Sheng Wang ◽  
Chun Yuan Shi ◽  
Zhi Yi Huang

Resistance spot welding (RSW) is being taken place by partial lap laser welding for the poor surface quality and bad airtight due to the pressure of electrodes. The shape of partial lap laser welding is similar to the vase. When the penetration of the joint is in a certain range, there is no welding trace on the outer surface. Laser welding temperature field numerical analysis based on Abaqus finite element analysis software is committed to obtain a suitable range of process parameters to improve production efficiency and automation by determining the joint penetration. To master the laser lap welding of stainless steel weld penetration state, the combination of three-dimensional positive cone + three-dimensional inverted cone + half-ellipsoid heat source model was established simulating stainless steel lap laser weld pool shape and forecasting the range of process parameters .


Author(s):  
Sohini Chowdhury ◽  
Yadaiah Nirsanametla ◽  
Muralidhar Manapuram

This work focuses on examining the influence of welding parameters under different welding atmospheres and evaluation of keyhole profile during fiber laser welding operation. The experiments are carried out in two different welding atmospheres, namely self-protected atmosphere of Ar gas and open atmospheric conditions. The effect of these two atmospheric conditions on weld profile formation and dimensions, and microstructural evolution for SS 316 plates are examined. In addition, the keyhole profile is evaluated by using a semi-analytical mathematical model, a point-by-point energy balance determination at the keyhole wall, which is mapped with experimentally measured weld macrographs for similar welding conditions. It has been determined that the weld quality is profound in the case of a self-protected atmosphere with respect to aspect ratio, weld defects, and microstructural characterization. Moreover, better weld bead profile and cleaner weld seam on the upper surface is determined in samples welded in a self-protected atmosphere.


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