Numerical Simulation of Molten Pool Dynamics in Laser Deep Penetration Welding of Aluminum Alloys
, Hongqiao Xu 1, Xiaohong Yang 2,3,*, Xingxing Wang 1, Shuai Li 1, Weimin Long 4 and Jian Zhang 5
Round 1
Reviewer 1 Report
In general, the authors give calculations and describe the processes, but due to the fact that there are no comparisons with experimental data, there is no understanding of the scientific novelty of the results obtained. In my opinion, the authors should discuss
In the Conclusion, the authors also give a brief description of the behavior of the welding zone during simulation, but there is no understanding of the significance of these results for their application.
Figure 2. The image must be presented in a larger size, since it is difficult to evaluate the geometry that the authors provide. In addition, there is no data on the sizes of these areas. Does the size of the selected area correspond to the calculated one? You need to add a scale bar.
Author Response
Detailed Response to Reviewer
Dear Editors and Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript
entitled “Numerical simulation of molten pool dynamics in laser deep penetration
welding of aluminum alloy” (ID: 1748521). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made detailed corrections point by point which we hope meet with approval. Moreover, the edits and changes in this revised manuscript were highlighted in red. The main corrections in the paper and the responds to the reviewer’s comments are listed below :
Responds to the Reviewer 1’s comments:
- In general, the authors give calculations and describe the processes, but due to the fact that there are no comparisons with experimental data, there is no understanding of the scientific novelty of the results obtained. In my opinion, the authors should discuss
Response: Thank you for your valuable advice. The discussion has been added to the paper.The detailed revision can be found in Page 16-18.
- In the Conclusion, the authors also give a brief description of the behavior of the welding zone during simulation, but there is no understanding of the significance of these results for their application.
Response: Thanks for your kind suggestion. Conclusions have been revised and the detailed revision can be found in Page 18. The weld defects of aluminum alloy obtained by laser welding included porosity, spatter, and so on, which would seriously affect the quality of the weld. The dynamic behavior of weld pool had a direct impact on the formation of welding defects. However, the flow field of the keyhole wall under different welding speeds has not been studied during laser deep penetration welding of aluminum alloy. And there was no research on the correlation of the keyhole, welding spatter, and molten pool flow with different welding speeds.
- Figure 2. The image must be presented in a larger size, since it is difficult to evaluate the geometry that the authors provide. In addition, there is no data on the sizes of these areas. Does the size of the selected area correspond to the calculated one? You need to add a scale bar.
Response: Thanks for your kind advice. The scale bar has been added to Figure 2. Cross-sectional observation by optical microscope was done to measure the width and depth of molten pool. In the paper, Figure 2 shows the comparison between the experimental weld seam cross section and the simulated molten pool for a welding speed of 3m/min. The detailed revision can be found in Page 6.
The authors would like to thanks again for the reviewers' useful and valuable views, comments and suggestions on our manuscript, which will make it more understandable and acceptable to readers. We had learned lots of things during the process of revising.
The manuscript has been resubmitted to your journal. We look forward to your positive response. Thank you very much! Best regard!
Corresponding author: Name: Jin Peng. E-mail: [email protected]
;Correspondence author: Xiaohong Yang . mail address: [email protected]
Author Response File: 
Author Response.docx
Reviewer 2 Report
1. Although the comparison between the calculated and experimental results are shown in Sec. 3.1, your mathematical modeling should be more carefully validated. For example, you should show additional experimental molten pool images for different welding speeds (3, 6, 9 m/min). In addition, you should describe how the molten pool shape was determined from the image because the shape appears to extend backward from the red dashed line in Figure 2. Cross-sectional observations by optical microscope or scanning electron microscope should be done to measure the width and depth of molten pool and compare them with the simulated results. Without such validation, subsequent simulated results in Sec. 3.2 and 3.2 will be completely meaningless.
2. In Table 1, why don’t you use temperature-dependent properties? For example, thermal expansion coefficient, convective heat transfer coefficient.
3. I could not better understand the novelty of your research in Abstract and Conclusion. Isn't what you are describing there something that has already been shown in previous studies? How will your research impact the field of welding research and industry? In addition, the introduction should not list the existing studies, but should clearly discuss what is already known and what is not yet known.
Author Response
Detailed Response to Reviewer
Dear Editors and Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript
entitled “Numerical simulation of molten pool dynamics in laser deep penetration
welding of aluminum alloy” (ID: 1748521). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made detailed corrections point by point which we hope meet with approval. Moreover, the edits and changes in this revised manuscript were highlighted in red. The main corrections in the paper and the responds to the reviewer’s comments are listed below :
Responds to the Reviewer 2’s comments:
- Although the comparison between the calculated and experimental results are shown in Sec. 3.1, your mathematical modeling should be more carefully validated. For example, you should show additional experimental molten pool images for different welding speeds (3, 6, 9 m/min). In addition, you should describe how the molten pool shape was determined from the image because the shape appears to extend backward from the red dashed line in Figure 2. Cross-sectional observations by optical microscope or scanning electron microscope should be done to measure the width and depth of molten pool and compare them with the simulated results. Without such validation, subsequent simulated results in Sec. 3.2 and 3.2 will be completely meaningless.
Response: Thank you for your valuable advice. Cross-sectional observation by optical microscope was done to measure the width and depth of molten pool. In the paper, Figure 2 shows the comparison between the experimental weld seam cross section and the simulated molten pool for a welding speed of 3m/min. The detailed revision can be found in Page 6.
Due to the impact of the novel coronavirus pneumonia, it is currently not possible to provide welding seam cross-sections with welding speeds of 6m/min and 9m/min. The weld defects of aluminum alloy obtained by laser welding included porosity, spatter, and so on, which would seriously affect the quality of the weld. The dynamic behavior of weld pool had a direct impact on the formation of welding defects.Therefore, the correctness of molten pool flow field is very important. From the article entitled “Elucidation of Phenomena in High Power Fiber Laser Welding and Development of Prevention Procedures of Welding Defects”, it can be seen that the low and high velocity flow fields of molten pool are shown in Figure 19.
The low-speed and high-speed molten pool flow field in this paper was consistent with the low-speed and high-speed molten pool flow field in Figure 19.
- In Table 1, why don’t you use temperature-dependent properties? For example, thermal expansion coefficient, convective heat transfer coefficient.
Response: Thanks for your kind suggestion. Thermophysical parameters have been added to the paper.The detailed revision can be found in Page 5-6.
- I could not better understand the novelty of your research in Abstract and Conclusion. Isn't what you are describing there something that has already been shown in previous studies? How will your research impact the field of welding research and industry? In addition, the introduction should not list the existing studies, but should clearly discuss what is already known and what is not yet known.
Response: Thanks for your kind advice.The abstract and sonclusions have been revised.And the introduction has been revised.
The authors would like to thanks again for the reviewers' useful and valuable views, comments and suggestions on our manuscript, which will make it more understandable and acceptable to readers. We had learned lots of things during the process of revising.
The manuscript has been resubmitted to your journal. We look forward to your positive response. Thank you very much! Best regard!
Corresponding author: Name: Jin Peng.E-mail: [email protected]; Correspondence: author: Xiaohong Yang . mail address: [email protected]
Author Response File: Author Response.docx
Reviewer 3 Report
In this paper, numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloy was established based on FLUENT 19.0 software. The three-dimensional transient behavior of keyhole, and the flow field of molten pool at different welding speeds were analyzed, and the influence of welding speed on the molten pool of aluminum alloy in laser welding was obtained. This is a very interesting paper, and was quite valuable to other researchers. The manuscript is well stucutured and written in concise English. It is recommended to accept for publication at its current format.
Author Response
Detailed Response to Reviewer
Dear Editors and Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript
entitled “Numerical simulation of molten pool dynamics in laser deep penetration
welding of aluminum alloy” (ID: 1748521). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made detailed corrections point by point which we hope meet with approval. Moreover, the edits and changes in this revised manuscript were highlighted in red. The main corrections in the paper and the responds to the reviewer’s comments are listed below :
Responds to the Reviewer 3’s comments:
- In this paper, numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloy was established based on FLUENT 19.0 software. The three-dimensional transient behavior of keyhole, and the flow field of molten pool at different welding speeds were analyzed, and the influence of welding speed on the molten pool of aluminum alloy in laser welding was obtained. This is a very interesting paper, and was quite valuable to other researchers. The manuscript is well stucutured and written in concise English. It is recommended to accept for publication at its current format. .
Response: Thank you for your advice!
The authors would like to thanks again for the reviewers' useful and valuable views, comments and suggestions on our manuscript, which will make it more understandable and acceptable to readers. We had learned lots of things during the process of revising.
The manuscript has been resubmitted to your journal. We look forward to your positive response. Thank you very much! Best regard!
Corresponding author: Name: Jin Peng .E-mail: [email protected];
Correspondence: author: Xiaohong Yang . mail address: [email protected]
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have made the necessary changes to the manuscript, I believe that the article can be accepted for publication.
Reviewer 2 Report
Thank you for revising your manuscript based on our reviews. It is interesting that the generation of welding spatters were directly related to the fluctuation of the size in the middle of the keyhole. In your subsequent papers, please validate the CFD simulation by comparing the experimental results with different scanning speeds.
