scholarly journals High-Speed X-Ray Transmission and Numerical Study of Melt Flows inside the Molten Pool during Laser Welding of Aluminum Alloy

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Jin Peng ◽  
Liqun Li ◽  
Shangyang Lin ◽  
Furong Zhang ◽  
Qinglong Pan ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Laser Welding ◽  
Welding Speed ◽  
Molten Pool ◽  
High Speed ◽  
Numerical Study ◽  
Flow Behavior ◽  
Front Wall ◽  
X Ray ◽  
Rear Part

By using the X-ray transmission imaging system, melt flows inside a molten pool were studied during laser welding of aluminum alloy at different welding speeds. Then, the correlation between temperature gradients along the direction of weld penetration and melt flows in the rear part of a molten pool was analyzed by using a three-dimensional numerical method. And the presented model was verified by experimental results. The corresponding investigation was carried out to further study the correlation between temperature gradient and melt flow behavior of the molten pool in the plate heated by preheating temperature. The results indicated that, in the rear part of the molten pool, the maximum flow velocity was located at the bottom of the molten pool. The melt metal in the rear molten pool caused by different welding speeds had significantly different flow trends. As the welding speed increased, the absorbed intensity on the keyhole front wall also increased as well as the recoil pressure that could maintain the keyhole opened. Consequently, the increase of the welding speed was more beneficial to improving the stability of the molten pool.

Effect of Welding Speed on Melt Flow Behavior in High Speed Laser Welding Process

2013 ◽  
Vol 40 (5) ◽  
pp. 0503001
Author(s):  
裴莹蕾 Pei Yinglei ◽  
单际国 Shan Jiguo ◽  
任家烈 Ren Jialie
Keyword(s):  
Laser Welding ◽  
Welding Speed ◽  
High Speed ◽  
Flow Behavior ◽  
Welding Process ◽  
Melt Flow ◽  
Laser Welding Process

Investigation of porosity in rotating laser-MIG hybrid welding A6N01 aluminum alloy

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940029
Author(s):  
Yanjie Yin ◽  
Hui Chen ◽  
Xiaoyi Yang ◽  
Shuang He
Keyword(s):  
Aluminum Alloy ◽  
Molten Pool ◽  
High Speed ◽  
Rotation Frequency ◽  
Good Prospect ◽  
Hybrid Welding ◽  
Weld Penetration ◽  
X Ray ◽  
Conventional Laser ◽  
Alloy Weld

In this study, rotating laser was employed to reduce the porosity defect in laser-MIG hybrid welding A6N01 aluminum alloy. The influence of laser rotating frequency and rotating radius on the weld were researched respectively. The images of the molten pool were acquired by the high-speed camera, and X-ray images of the weld were calculated by binarization. The result shows that rotating laser-MIG hybrid welding has a dramatic effect on suppressing the generation of porosity, which indicates the possibility to obtain the A6N01 aluminum alloy weld with few pores. With proper parameters about rotation frequency (50 Hz) and rotation radius (2 mm), the porosity decreased obviously from 8.41% to 5.68%, and there was hardly distinct change in the weld penetration. The keyhole stability of rotating laser-MIG hybrid welding was improved, compared with the conventional laser-MIG hybrid welding. On account of laser beam stirring the metal molten pool, it was beneficial for the pores to escape from the molten pool. The rotating laser-MIG hybrid welding shows a good prospect.

Intense X-Ray Measurement of Transient Hydraulic Phenomena in Molten Pool During Laser Welding Process

2012 ◽  
Author(s):  
Tomonori Yamada ◽  
Takahisa Shobu ◽  
Susumu Yamashita ◽  
Takemitsu Ogawa ◽  
Kenta Sugihara ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Laser Welding ◽  
Phase Change ◽  
Molten Pool ◽  
Welding Process ◽  
In Situ Observation ◽  
Interface Shape ◽  
X Ray ◽  
Laser Welding Process

Spatial temperature distribution during the laser welding process has a huge effect on any residual stress distribution. Therefore, understanding of the transient hydraulic phenomena which affect the temperature distribution in the molten pool is very important. In this work, intense X-ray measurement at the Super Photon ring-8 GeV (SPring-8) facility well carried out to document the transient hydraulic phenomena in the molten pool during the laser welding process. Based on in-situ observation of inside material, the experimental results confirmed that the molten pool shapes, hydraulic condition such as flow velocity, etc.. In the case of laser power is 330W and spot diameter is 1mm, we observed the steady flow which consisted of downward flow and upward flow. The flow velocities were about 19.5 mm/s and 9.0 mm/s, respectively. Moreover, the rate of phase change was obtained from molten pool shape during laser welding. The rate of phase change was not constant during laser welding. Thus the interface shape might change at all time. Therefore, to evaluate the temperature distribution, it is necessary to consider not only convection but also the interface shape. These results indicate that the intense X-ray measurement during laser welding is very effective for the understanding the molten pool phenomena.

scholarly journals Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4211 ◽  
Author(s):  
Anton Naumov ◽  
Iuliia Morozova ◽  
Evgenii Rylkov ◽  
Aleksei Obrosov ◽  
Fedor Isupov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Welding Speed ◽  
Welded Joints ◽  
High Speed ◽  
Structural Characteristics ◽  
Tensile Fracture ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Aluminum Sheets

The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

Research on Stress Calibration Technology on Aluminum of High-Speed Train Body Structure by Nondestructive X-Ray Method Measurement

2011 ◽  
Vol 189-193 ◽  
pp. 734-742
Author(s):  
Hua Ji ◽  
Hui Chen ◽  
Guo Qing Gou ◽  
Da Li ◽  
Yan Liu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Stress Measurement ◽  
Diffraction Method ◽  
Welding Residual Stress ◽  
X Ray Diffraction ◽  
Ray Method ◽  
Electrometric Method ◽  
X Ray ◽  
6082 Aluminum Alloy

X-ray diffraction method has been employed to calibrate the stress of 6082 aluminum alloy which has been widely used among modern industrial products. Based on elastic tensile conditions, by designing rod sample of uniform intensity calibration (RSUIC), the stress measurement by X-ray diffraction method has been verificated by using elastic tensile theory calculation method and electrometric method. The results show that the stress measured by the tensile stress theoretical calculation, electrometric method and X-ray diffraction method was in good accordance with each other. And the matching relation between the surface stress measured by X-ray diffraction and the internal stress is investigated. The research will lay a foundation for the application of iXRD stress instrument for nondestructive measuring the welding residual stress of aluminum alloy.

Numerical study of spatter formation during fiber laser welding of aluminum alloy

2018 ◽  
Vol 31 ◽  
pp. 72-79 ◽  
Author(s):  
Dabin Zhang ◽  
Canli Li ◽  
Xixia Liu ◽  
Yang Cao ◽  
Dongsheng Wu
Keyword(s):  
Aluminum Alloy ◽  
Laser Welding ◽  
Fiber Laser ◽  
Numerical Study ◽  
Fiber Laser Welding
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