Multi-Objective Optimization of Surface Integrity in the Grind-Hardening Process
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript presents a multi-objective optimization study of the grind-hardening process of the 42CrMo steel. The input variables tested by the authors were workpiece speed (vw), radial depth of cut (ae), and grinding wheel speed (vs). The output parameter evaluated was the surface integrity, analyzed in terms of surface roughness (Ra parameter), burr size, and effective hardened layer depth. The topic of the manuscript is interesting, in my opinion. Also, the manuscript is relatively well-organized. Nevertheless, revisions must be carried out before considering publication. My comments are addressed as follows:
1. The abstract lacks contextualization.
2. Revise the citation format of references. The brackets are missing.
3. I honestly disagree with the strategy of presenting an introduction using “Research background” and “Current status of research on surface integrity in grinding operation” topics. I suggest presenting an “Introduction” only. Additionally, the manuscript contextualization and literature review are poor. The authors must present the concept regarding the grind-hardening process in detail, including its importance. Furthermore, I suggest presenting more references that cover the grind-hardening process specifically, and/or more references covering subsurface alteration due to grinding.
4. Figure 1. To avoid the repetition of the term “surface quality”, I suggest changing the second one to “Subsurface quality”. Additionally, what is “Surface organization”? I suggest revising Figure 1.
5. First paragraph of topic 3.1. Please, revise the first words. In addition, the information regarding grind-hardening should be presented in the introduction section.
6. Was the grinding wheel dressed before each test? I suggest presenting the dressing parameters.
6. First paragraph of page 4. Information regarding the 42CrMo steel lack literature support.
7. On line 113, the authors wrote: “[…] Then, the surface grinder was used to fine-grind the surface and side of the workpiece. […]”. This is confusing. The authors must specify the workpiece geometry and its surface that was submitted to the grinding operation more clearly.
8. I suppose that the grinding method was peripheral grinding. If so, the “grinding depth” should be the radial depth of cut (ae). Please, consider checking this detail.
9. Figure 5 is not necessary in my opinion.
10. The authors use the term “grinding line speed”. I suggest using grinding wheel speed, or wheel speed.
11. Figure 7. Was there any hardness reduction observed at the “hardness change transition layer”? I’m asking this because, to the best of my knowledge, the presence of a tempered region beneath the hardened layer is not so uncommon.
12. Table 4. Workpiece speed (vw) is presented twice. Please, revise.
13. Topic 4. In general, the discussions of the results lack literature support. I suggest including references to support the discussions.
14. Table 6 is confusing. I suggest improving its presentation. Additionally, some explanations regarding the table could be added to the manuscript to improve the understanding.
15. Table 8. It also needs improvements in its presentation. Furthermore, the discussion on lines 381-388 must include comments regarding the errors concerning burrs size (S) and the effective hardened layer (h).
16. The conclusion topic could be improved by adding comments regarding the errors in the validation results, especially considering the ones for the S and h output parameters.
17. I suggest removing lines 408-410.
18. References. Please, revise references 8 and 15. They lack the publication year.
Author Response
Dear editor and reviewers,
Thank you very much for your kind letter, along with the reviewers’ constructive comments concerning our manuscript (coatings-3064316). We have thoroughly considered all the comments and revised our manuscript substantially.
The revised portions were marked in red in the revised manuscript.
Once again, thank you very much for your comments and suggestions.
We have tried our best to modify and improve the quality of our manuscript. These changes do not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ work greatly, and hope that those corrections will meet the requirement.
We hope the quality of our manuscript would meet the publication standard of Coatings with these modifications and improvements based on your suggestions and the reviewers’ comments. Once again, we acknowledge that your comments and constructive suggestions are rather valuable in improving the quality of our paper.
Please see the attachment.
Best wishes,
Sincerely yours,
Chunyan Wang
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis submission coatings-3064316 describes the multi-objective optimization of surface integrity in under grind hardening process. Its subject is interesting; however, some remarks should be done:
1. Authors do not followed rules for presenting literature sources (symbols [ ]) and do not checked typos,
2. Figure 1 should be changed dividing it into some areas; Authors need to be aware that when dealing with surface integrity characteristics, they should be described correctly,
3. It be difficult understand differences between typical grinding and hard grinding under high temperatures (section 3). In my opinion, in this cause only scorching and big defects of the surface layer can be achieved,
4. The Authors wrote, that it is imperative to optimize both the heat generation during grinding and the heat transfer to the workpiece surface. But how one can do it? by testing? by calculating? And, in general, is this process is named the Creep feed grinding? And if so, it is a contemporary process, not a process of the 1930s.,
5. “The hardness of the high hardening zone of the grind-hardened layer was always between 620-700 HV”; It is only words, where does the research confirmation came from?
6. Burrs images should be clarified,
7. Microstructures, heat affected zones and so on should be described,’
8. What does it mean "half martensite" area?
9. What statistical control was used and also soft type?
10. What optimization type was used; only words were used in submission but where are numbers?
11. All research units should be described,
12. Ra is only one of roughness parameters; for what others were not measured? Ra values give poor information.
Author Response
Dear reviewer,
Thank you very much for your kind letter, along with the reviewers’ constructive comments concerning our manuscript (coatings-3064316). We have thoroughly considered all the comments and revised our manuscript substantially.
The revised portions were marked in red in the revised manuscript.
Once again, thank you very much for your comments and suggestions.
We have tried our best to modify and improve the quality of our manuscript. These changes do not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ work greatly, and hope that those corrections will meet the requirement.
We hope the quality of our manuscript would meet the publication standard of Coatings with these modifications and improvements based on your suggestions and the reviewers’ comments. Once again, we acknowledge that your comments and constructive suggestions are rather valuable in improving the quality of our paper.
Please see the attachment.
Best wishes,
Sincerely yours,
Chunyan Wang
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper studies the influence of the parameters in a grind-hardness process in a CrMo steel by using both Experimental design and Multi-response optimization analysis. Results show that the models should not be based on the roughness of the samples since this parameter generates a greater error in the model predictions. Also, the authors found that the grinding depth is the parameter with the greatest influence on the depth of the effective hardened layer and surface roughness. The paper is well structured easy to read and pretty interesting for the community. I have only some minor suggestions mainly with the reference formatting:
-Line 23 correct data 1941
-Please, correct the reference and put all between the Square brackets []
-Lines 41, 49, 52, 69, 73 include the number reference after et al.
-Figure 1. There are two squares with name surface quality – if they are the same should be joined in one, but maybe if they are differents change the names.
-Please in Table 3 could you add a column with the symbol of each parameter? This is going to help in the easy lecture.
-Line 123 - 1.9 mm10?
-Table 4 please translate the Chinese word
-I believe that you need to re-write the line 181. In Fig. 8b the grinding line speed influences the surface roughness. A value of around 30 m/s seems to be optimum to reduce the Ra.
-The value of the fixed parameter must be informed in Fig. 8 and Fig. 9. For example, what was the speed of the grinding line in Figure 8a? and also for the rest of the figures.
-Paragraphs lines 183 to 192 and 200 to 220 need some references to reinforce the several affirmations about the mechanisms.
-Paragraph 200 to 220 – You are talking about temperature, but was it measure? if it was, should be reported.
Fig. 11 – please remove the lines in the Table.
Author Response
Dear reviewers,
Thank you very much for your kind letter, along with the reviewers’ constructive comments concerning our manuscript (coatings-3064316). We have thoroughly considered all the comments and revised our manuscript substantially.
The revised portions were marked in red in the revised manuscript.
Once again, thank you very much for your comments and suggestions.
We have tried our best to modify and improve the quality of our manuscript. These changes do not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ work greatly, and hope that those corrections will meet the requirement.
We hope the quality of our manuscript would meet the publication standard of Coatings with these modifications and improvements based on your suggestions and the reviewers’ comments. Once again, we acknowledge that your comments and constructive suggestions are rather valuable in improving the quality of our paper.
Please see the attachment.
Best wishes,
Sincerely yours,
Chunyan Wang
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have answered the comments and improved the manuscript accordingly. Thus, my recommendation is to accept the manuscript. Please just revise the line 107. The sentence “The text continues here.” should be removed.
Reviewer 2 Report
Comments and Suggestions for AuthorsI have not connents
