Advanced Porosity Control of CP780 Galvanized Steel During Gas Metal Arc Welding with Pulsed Arc

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper studies the problem of porosity control in welding galvanized steel CP780 by gas metal arc welding with pulsed arc (GMAW-P). The relevance is due to the widespread use of CP780 in the automotive industry, where strength, light weight and corrosion resistance are important. However, zinc coating promotes the formation of pores due to zinc evaporation during welding. The aim of the work is to optimize the welding parameters to minimize porosity. Experiments were carried out using Taguchi L9 orthogonal array to analyze the effects of peak current, pulse time and pulse frequency. The results showed that porosity is significantly reduced at a peak current of 313 A, a frequency of 10 Hz and a pulse time of 10 ms. Microstructural analysis revealed the presence of different phases in the heat-affected zone. A predictive model for predicting porosity with a high coefficient of determination (R2 = 99.97%) is developed. The importance of the work lies in the proposal of optimal welding parameters for improving the quality of welded joints of CP780 galvanized steel, which is important for the automotive industry.
There are a number of comments on the review that require revision:
1. The introduction well substantiates the relevance of using CP galvanized steels in the automotive industry. However, this section can be strengthened by providing specific examples of car parts or units where the use of such steels is most promising, and where the problem of porosity during welding is the greatest difficulty.
2. Lines 268-280. In the section devoted to the assessment of the porosity of welded joints using X-ray images, the description of defects is too general. A more rigorous classification of defects based on international standards (e.g. ISO 6520-1) should be used, and not only the presence but also the type, size, shape and location of defects should be indicated. 3. It is necessary to consider the influence of the shape and size of the pores on the mechanical properties of the welded joint, and to indicate which types of pores are most dangerous in terms of strength and durability.
4. It is also necessary to consider the interaction of various parameters (e.g., peak current and pulse frequency) and their influence on the temperature of the weld pool, the rate of metal crystallization, and the process of gas removal.
5. Lines 304-332. The analysis of the macro- and microstructure of welded joints requires more description. It is necessary to indicate the sizes of the heat-affected zones (HAZ), the structure of the weld metal and HAZ, as well as the presence and distribution of various phases (bainite, martensite, ferrite, residual austenite). In addition, it is necessary to consider the influence of the welding parameters on the structure of the metal and its properties.
6. Lines 519-542. The description of the mathematical model for predicting porosity requires more specificity. It is necessary to indicate the type of regression equation, the values ​​of the coefficients for various parameters, as well as the statistical characteristics of the model (e.g., standard error, confidence interval).
7. Lines 508–517. In the analysis of variance (ANOVA) section, you must specify the chosen significance level (e.g., α = 0.05) and justify its choice. This parameter determines the probability of a type I error (rejection of a true null hypothesis) and affects the reliability of the analysis results.

Author Response

We appreciate your attention and support.

A response letter is prepared with all the Reviewer 1 comments and questions.

Regards

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract is an important section to attract readers to the paper. However, the current abstract does not sufficiently present the necessity of this study. Please add a sentence to clarify the research need.

 

The material used in this study is commercial CP steel. However, the experimental procedure does not provide information on where or how this material was manufactured. In addition, its physical properties are not presented. Please provide detailed information regarding the material.

 

When pores exist in welds, they can cause structural failure due to stress concentration. Therefore, welding should be performed without pores as a basic principle. Please clarify the reason for analyzing pores. Without sufficient justification, it is difficult to accept the purpose of this analysis.

 

The captions of Figures 5 and 6 do not provide enough explanation to fully understand the figures. Please enhance the captions.

 

Figure 7 shows the microstructure of the weld. However, the black boundary line is difficult to identify. Please change it to a bright dotted line to make it more recognizable for readers.

 

The section numbering jumps from 3.1 to 3.4. Please check and revise accordingly. Also, check the subsequent section numbers.

 

What does "3.6 Arc" mean? Please revise it properly.

 

The caption of Table 10 is unclear. It appears to be incomplete. Please check and revise it.

 

It is unclear what Figure 14 is showing and what was confirmed through it. Please enhance the figure and caption to clearly explain its purpose and content.

 

Although this study presents many results, the discussion is insufficient. Please strengthen the discussion section.

 

The results section only lists the findings without proper discussion. Please reduce the results to fewer than four paragraphs and add a proper discussion. This will help in constructing a more suitable conclusion.

Comments on the Quality of English Language

A comprehensive revision of the language is necessary to enhance the overall quality of the paper.

Author Response

We appreciate your attention and support.

A response letter is prepared with all the Reviewer 2 comments and questions.

Regards

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors provided detailed responses to all my reviewer comments, demonstrating an understanding of the issues raised. The article has been revised.

Author Response

We appreciate your comments and recommendations.

We are glad that you found our research and manuscript ready to be accepted and published.

Regards

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract has not been improved.
The abstract still lacks clarity and focus. It does not effectively summarize the objectives, methods, results, and significance of the study. A complete rewrite is necessary to properly convey the core message of the work.

Material information is missing.
There is still no specific information about the materials used in the study. This is a critical omission. Please provide detailed descriptions, including composition, source, and any relevant properties.

Sentence structure disrupts paragraph flow.
Although revisions were made, the addition of new sentences has disrupted the logical flow of the paragraph. The section should be reorganized to maintain coherence and a consistent narrative.

Figure caption remains unclear.
The revised caption still does not help the reader understand the figure. Captions should be self-explanatory and clearly describe what is being shown and why it matters in the context of the study.

Properly revised.
This section has been appropriately revised and is now acceptable.

Properly revised.
This point has also been adequately addressed.

Properly revised.
No further revisions are necessary for this item.

Porosity explanation remains insufficient.
The explanation of porosity is still vague. It must be clarified whose or what type of porosity is being discussed (e.g., total, effective, micro, etc.). The text should be revised so that readers can fully understand the context and implications.

Properly revised.
This section is now acceptable.

Not improved; lacks proper discussion.
The discussion section remains underdeveloped. It appears that the author may have confused the discussion and conclusion sections. This section must interpret results within the context of previous research. Avoid using translation software—comprehension and original synthesis are required.

Not revised.
No changes were made despite previous comments. This section still needs significant improvement.

Author Response

REVIEWER 2

Reviewer(s)' Comments to Author:

 

The reviewer has agreed to some comments and observations from the previous round of revision. There are some comments still we will discuss and address herein.

 

1. The abstract has not been improved. The abstract still lacks clarity and focus. It does not effectively summarize the objectives, methods, results, and significance of the study. A complete rewrite is necessary to properly convey the core message of the work.

= We appreciate your comment. What we focused on in the abstract was in mentioning the goal of our research, which is critical for industrial applications such as automotive and agriculture. By evaluating and analyzing the welding parameters of the GMAW-Pulsed process (peak current (I_p), pulse time (t_p), and pulse frequency (f)) we were able to observe good effects and performance of the welding through the HAZ.

 

2. Material information is missing. There is still no specific information about the materials used in the study. This is a critical omission. Please provide detailed descriptions, including composition, source, and any relevant properties.

= Material information is provided in section 2, Table 1 and Table 2. As we previously mentioned, due to the confidentiality agreement we have with our industrial partners, we can’t detail too much information about the material. CP780 is a commercially available material from a few sources, mainly in Asia and Europe. Since the material is being developed by these suppliers to improve its weldability and other material attributes, we can’t specify more information about it.

 

3. Sentence structure disrupts paragraph flow. Although revisions were made, the addition of new sentences has disrupted the logical flow of the paragraph. The section should be reorganized to maintain coherence and a consistent narrative.

= We appreciate your observation. We have modified the main manuscript, and gave a better flow for readers to understand better.

 

4. Figure captions remain unclear. The revised caption still does not help the reader understand the figure. Captions should be self-explanatory and clearly describe what is being shown and why it matters in the context of the study.

= We appreciate your observation. The explanation of the figures is based on the main manuscript. The captions are general descriptions of what we show to the readers. Once you read the text, can relate to the figures/charts and understand better.

 

5. Porosity explanation remains insufficient. The explanation of porosity is still vague. It must be clarified whose or what type of porosity is being discussed (e.g., total, effective, micro, etc.). The text should be revised so that readers can fully understand the context and implications.

= We appreciate your observation. In the industrial argot, which is the type of research  we do and apply, porosity is porosity according to the ASTM standards and the general practices (which we can’t share with you or the general public, also due to confidentiality). Text was revised and updated accordingly respecting these aspects I previously mentioned here.

 

6. Not improved; lacks proper discussion. The discussion section remains underdeveloped. It appears that the author may have confused the discussion and conclusion sections. This section must interpret results within the context of previous research. Avoid using translation software—comprehension and original synthesis are required.

= We appreciate your observation. We modified the main manuscript, and revised this section, per your request, also moving some aspects of the conclusions so it could be better understood by the readers. We are not using any translation software, just the industrial argot I previously mentioned.

 

7. Not revised. No changes were made despite previous comments. This section still needs significant improvement.

= We modified the main manuscript, and revised this section, per your request, also moving some aspects of the conclusions so it could be better understood by the readers. We do not use any translation software, just the industrial argot I previously mentioned