Residual Stress and Bead Profile Analysis of Pulsed Nd:YAG Laser Lap Welding

2013 ◽  
Vol 284-287 ◽  
pp. 915-918
Author(s):  
Tsung Pin Hung ◽  
Chao Ming Hsu ◽  
Ah Der Lin ◽  
Jao Hwa Kuang
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Nd:Yag Laser ◽  
Pulsed Laser ◽  
Welding Process ◽  
Surface Flux ◽  
Pulsed Nd:Yag Laser ◽  
Finite Element Software ◽  
Laser Lap Welding ◽  
Lap Welding

The weld bead temperature distribution and shape during pulsed Nd:YAG laser lap welding are studied. A volumetric heat source model is derived to include the surface flux and the keyhole heat transfer effects in the pulsed laser lap welding process. The proposed pulsed laser heat transfer mode is employed in a simulation with the commercial finite element software Marc. The numerically computed results of the weld pool dimensions are compared with the experimental results. The comparison shows a good agreement between the simulated and measurement results, indicating that the proposed model is feasible. The results reveal that the pulse duration and spot pitch have considerable influence on the temperature field distribution and the residual stress distribution.

The Influence of Welding Parameters on Heat Transfer Efficiency of Hybrid Pulsed Nd: YAG/GTAW Welding

2015 ◽  
Vol 1088 ◽  
pp. 807-813
Author(s):  
Miao Xia Xie ◽  
Lin Jie Zhang
Keyword(s):  
Heat Transfer ◽  
Nd:Yag Laser ◽  
Welding Process ◽  
Transfer Efficiency ◽  
304 Stainless Steel ◽  
Welding Parameters ◽  
Hybrid Welding ◽  
Pulsed Nd:Yag Laser ◽  
Heat Transfer Efficiency ◽  
Cross Section Area

In this work, effects of major welding parameters, such as laser power, defocus distance of laser beam, inter-heat sources distance and welding speed, on weld geometry were investigated for pulsed Nd:YAG laser/GTAW hybrid welding of 304 stainless steel. Heat transfer efficiency of pulsed Nd:YAG laser/GTAW hybrid welding process was quantitativly analyzed based on rosenthal equation. Furthermore, melting efficiency was determined from the measured welding seams cross section area.

scholarly journals Interfacial Characteristics of Dissimilar Ti6Al4V/AA6060 Lap Joint by Pulsed Nd:YAG Laser Welding

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 71 ◽  
Author(s):  
Xin Xue ◽  
António Pereira ◽  
Gabriela Vincze ◽  
Xinyong Wu ◽  
Juan Liao
Keyword(s):  
Laser Welding ◽  
Nd:Yag Laser ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Mechanical Resistance ◽  
Lap Joint ◽  
Important Indicator ◽  
Pulsed Nd:Yag Laser ◽  
Pulsed Nd:Yag Laser Welding ◽  
Interfacial Characteristics

This paper focuses on the interfacial characteristics of dissimilar Ti6Al4V/AA6060 lap joint produced by pulsed Nd:YAG laser beam welding. The process-sensitivity analysis of welding-induced interface joining quality was performed by using the orthogonal design method. Microstructural tests such as scanning electron microscopy and energy dispersive X-ray spectroscopy were used to observe the interfacial characteristics. The mechanism of interfacial crack initiation, which is an important indicator of joint property and performance, was assessed and analyzed. The preferred propagation paths of welding cracks along the interfaces of different intermetallic layers with high dislocation density were analyzed and discussed in-depth. The results indicate that discontinuous potential phases in the micro-crack tip would mitigate the mechanical resistance or performance of the welded joint, while the continuous intermetallic layer can lead to a sound jointing performance under pulsed Nd:YAG laser welding process.

Influences of Overall and Local PWHT on Residual Stresses in the Under-Matching Welded Joints

2015 ◽  
Author(s):  
Yuwen Qian ◽  
Jianping Zhao
Keyword(s):  
Residual Stress ◽  
Welded Joint ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Engineering Practice ◽  
Transverse Stress ◽  
Longitudinal Stress ◽  
Finite Element Software ◽  
The Common ◽  
Postweld Heat

The under-matching welded joint is commonly used in engineering practice and the postweld heat treatment (PWHT) is the common method to reduce the residual stress in the welded joint, while the research on the under-matching welded joint after PWHT is few. The finite element software-ABAQUS is used to simulate the welding process and PWHT process of the under-matching welded joint which is the combination of CF62 (base metal) and 316L (weld) in this paper. The discussion of the influences of both overall and local PWHT on the residual stress in the under-matching welded joint is based on the experimental verification. And the influences of the two methods are compared to propose the better PWHT method to the under-matching welded joint. The results show that both overall and local PWHT can reduce the residual stress in the under-matching welded joint significantly, especially the lower transverse stress than the longitudinal stress. The distribution of the residual stress in the under-matching welded joint after the local PWHT is a little more uniform than that after the overall PWHT. The local PWHT is recommended to the under-matching welded joint in this paper.

scholarly journals Welding of Aluminum Using a Pulsed Nd:YAG Laser

10.14311/1295 ◽  
2010 ◽  
Vol 50 (6) ◽  
Author(s):  
M. Nerádová ◽  
P. Kovačócy
Keyword(s):  
Laser Welding ◽  
Optical Microscopy ◽  
Nd:Yag Laser ◽  
Pure Aluminum ◽  
Pulsed Laser ◽  
Hardness Measurement ◽  
Pulsed Nd:Yag Laser ◽  
Pulsed Laser Welding

This paper deals with pulsed laser welding of aluminum using an Nd:YAG laser with wavelength 1.06 μm. Technically pure aluminum (95.50 wt. %) was used as the welded material. Eighteen welds (penetration passes) were fabricated in the experiment. Optical microscopy was used to assess the influence of changes in the parameters of the pulsed laser on the quality and geometry of the penetration passes of aluminum and on the hardness measurement through the interface of the welds. The results show that the geometry of the penetration passes was influenced above all by the position of the beam focus.

scholarly journals Estimation formula for residual stress from the blind-hole drilling method

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401878740 ◽  
Author(s):  
Chi-Liang Kung ◽  
Ah-Der Lin ◽  
Po-Wei Huang ◽  
Chao-Ming Hsu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Parameter Group ◽  
Blind Hole ◽  
Finite Element Software ◽  
Inconel 690 ◽  
Stress Components

In this study, the accuracy of blind-hole method on weld residual stress estimation is investigated. A modified parameter group has also proposed to improve the accuracy. The thermal-elastic-plastic finite element model is employed to build up the residual stress distribution and the blind-hole process. The MSC Marc finite element software package is used to simulate the welding process and the welding residual stress and strain distributions around the weld of two inconel 690 alloy plates filled with I-52 GTAW filler. Then the process of the traditional blind hole is simulated by employing the inactive elements. The data of the residual strain variations of strain gages located around the blind hole is introduced into the blind-hole method to estimate the original residual stress components at the hole center. The effects of drilling depth, drilling size, gage radius, gage position, and the distance on the accuracy of estimated residual stress have also been studied and discussed. Based on the residual stress components simulated from the welding process, a modified stress parameter group has also been proposed to improve the accuracy of blind-hole method. Numerical results indicate that the accuracy of estimated residual stress can be improved significantly by employing the proposed blind-hole parameters.

Comparison of Experimental and Numerical Analysis Data for BMI Mock-Up With Dissimilar Metal Welds

2008 ◽  
Author(s):  
Seung-Cheon Yu ◽  
Yoon-Suk Chang ◽  
Young-Jin Kim ◽  
Sung-Woo Kim ◽  
Seong-Sik Hwang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Welding Process ◽  
Analysis Data ◽  
Test Method ◽  
Heat Transfer Analysis ◽  
Numerical Analyses ◽  
Primary Coolant ◽  
Control Rod ◽  
Dissimilar Metal

During the last decade, several defects due to primary water stress corrosion cracking (PWSCC) have been reported at bottom-mounted instrumentation (BMI) and control rod drive mechanism nozzles. The exact locations were dissimilar metal weld parts which are greatly important because the cracking could lead to leakage of primary coolant. The PWSCC of BMI mock-up’s penetration with dissimilar metal welds was examined by using doped steam test method by Korea Atomic Energy Research Institute. In this work, numerical analyses are performed for the same environment condition with the doped steam test. With respect to the numerical analyses, heat transfer analyses are carried out based on thermal conduction. The welding paths are simulated by using lumped path method for conservative evaluation and model change (remove/rebirth) method. Then residual stress analyses are conducted using the heat transfer analysis results, in which annealing effect of welding process simulation is considered for resetting the plastic deformation. However, the plastic behaviour of steels during phase transformations is not considered with experimental data. In addition, the consequence of weld residual stress that is known as the cause of PWSCC is being investigated.

scholarly journals Numerical simulation and experimental verification of laser multi-section welding

2020 ◽  
Author(s):  
Jia Liu ◽  
Tao Jiang ◽  
Yan Shi ◽  
Hongyin Zhu ◽  
Yuchi Dai
Keyword(s):  
Numerical Simulation ◽  
Duty Cycle ◽  
Average Power ◽  
Welding Process ◽  
Element Model ◽  
Simulation Software ◽  
Experimental Results ◽  
Welding Method ◽  
Laser Lap Welding ◽  
Lap Welding

Abstract Aiming at the problems of large welding deformation and spatter in resistance spot welding of traditional lube oil cooler plate, a new welding method: laser multi-section welding is proposed. The major processes here involved were a finite element model of pulsed laser lap welding established using SYSWELD simulation software, and the laser welding process of different welding methods. Study the influence of different welding methods on welding quality, Optimize the parameters of average power and duty cycle according to the comparative analysis of experimental results and numerical simulation Experimental results indicate: When the new 6-sections welding method is adopted, the resulting welded joint has the most uniform heat input, the largest welding fusion area, the tensile properties of the welded joints were significantly improved, however, there are still pores. By changing the duty cycle, air holes can be effectively eliminated to further improve the quality of the joint.

Numerical Simulation of Cr12MoV Steel during Quenching Process

2014 ◽  
Vol 989-994 ◽  
pp. 751-754
Author(s):  
Wei Zhang ◽  
Zhou De Qu ◽  
Xiao Hu Deng ◽  
Xing Wang Duan
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Heat Transfer Coefficient ◽  
Surface Heat ◽  
Finite Element Software ◽  
Quenching Process ◽  
Surface Heat Transfer Coefficient ◽  
Nonlinear Surface

The excessive residual stress induced by quenching in steels will easily result in distortion and failure of parts. In order to obtain the more suitable quenchant, quenching process of Cr12MoV steel with different mediums involving water and oil are simulated, respectively. In present paper, the influence of nonlinear surface heat transfer coefficient, thermodynamic parameters and latent heat are considered comprehensively. The distribution of temperature, microstructure, hardness and residual stress after quenching for Cr12MoV steel are simulated by DEFORM finite element software. According to the results mentioned above, the variations of each field of the steel are analyzed.

Nd:YAG laser lap welding of coated aluminium alloys

1997 ◽  
Author(s):  
T. Forsman ◽  
J. Powell ◽  
C. Magnusson
Keyword(s):  
Nd:Yag Laser ◽  
Aluminium Alloys ◽  
Laser Lap Welding ◽  
Lap Welding
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