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Open AccessArticle
Peer-Review Record

Research on Mechanical Properties of 210Cr12 Shaft Surface Processed with Rolling

Coatings 2020, 10(7), 611; https://doi.org/10.3390/coatings10070611
Reviewer 1: Jose Antonio Travieso-Rodriguez
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Coatings 2020, 10(7), 611; https://doi.org/10.3390/coatings10070611
Received: 15 April 2020 / Revised: 24 June 2020 / Accepted: 24 June 2020 / Published: 28 June 2020

Round 1

Reviewer 1 Report

This paper presents a study on a manufacturing process widely used in industry to improve the surface and mechanical properties of the materials in which it is used. I have some comments that I would like clarified before recommending whether or not it can be published in this journal.

  1. By the way of putting the “and” at the end of the corresponding author, there seems to be another author. I recommended to put: Peiquan Guo1*
  2. It would be nice to specify the standard that is used to name the materials. Chinese standards are not those used in all countries.
  3. Based on which criteria, variables and their values have been chosen?
  4. Why have variables such as the previous surface state, not been taken into account in this study?
  5. Which are the geometric characteristics of the roller?
  6. On line 116, I think it would be interesting to put Chrome instead of Cr at the beginning of the second sentence.
  7. Table 2 shows the mean of the 5 values taken on the different specimens, don’t it? If it is like this, I think is also necessary to declare the errors or the typical deviation of these values.
  8. Table 2 and Figures 4 and 5, show the same information. I think that one of them (i.e. Table 2), is not necessary. But in figures 4 and 5 it is also necessary to put the error bars. The same happen with Table 3 and figures 7 and 8; and Table 4 and figure 9.
  9. In cases of curves of graphs 4 and 5, it would be interesting to know the numerical fitting level. For example, the curve for 2 cycles in figure 4 fits worse than all the others. The same for Figures 7 and 8.
  10. In lines 154-156, a new element is introduced in the analysis (the cost of the process), to make a decision, but it is not explicitly stated how costs influence. In other words, there is no cost comparison for each process, nor is it stated how those costs are calculated.
  11. In figure 7, curves for 1 and 2 cycles does not seems similar to the rest of the curves. Can you explain why do you think it happens? In principle Residuals stresses and hardness have some relation, and in case of residuals stresses the fit of the curves that you have presented are very similar.
  12. On line 198, you declare that the Ra of initial pieces is 3.079 μ I think that in the same line of the previous comments, if it is the mean value of different measurements, error have to be declare.
  13. There is something very important in this kind of study demonstrate by many recent studies, like the ones listed below. The roughness in the pieces before rolling is very important factor, so if this parameter changes for the different specimens it could be a problem. So, how can the authors justify not having taken this parameter into account as a process variable?
  • Jerez-Mesa, Ramón, et al. "Comprehensive analysis of surface integrity modification of ball-end milled Ti-6Al-4V surfaces through vibration-assisted ball burnishing." Journal of Materials Processing Technology 267 (2019): 230-240.
  • Jerez-Mesa, Ramón, et al. "Topological surface integrity modification of AISI 1038 alloy after vibration-assisted ball burnishing." Surface and Coatings Technology349 (2018): 364-377.
  1. The last comment is about the novelty of this paper. How could you differentiate your study of the rest recently published about almost the same topic?

Author Response

    Thank you very much for your comments and suggestions. We have studied the valuable comments from you carefully, and tried our best to revise the manuscript. The point to point responds to the  comments are listed as following:

Comment 1: By the way of putting the “and” at the end of the corresponding author, there seems to be another author. I recommended to put: Peiquan Guo1*

Response 1: Thank you for your careful work. We have added the “and” at the end of the corresponding author.

Comment 2: It would be nice to specify the standard that is used to name the materials. Chinese standards are not those used in all countries.

Response 2: Thank you for your advice, we have corrected the name of materials, and put 210Cr12 instead of Cr12.

Comment 3: Based on which criteria, variables and their values have been chosen?

Response 3: We are very sorry for our incorrect writing, we have rewritten the sentences, please see the lines from 138 to 142.

Comment 4: Why have variables such as the previous surface state, not been taken into account in this study?

Response 4: In this study, the initial residual stress on the specimen surface is tensile stress of 52 MPa.

Comment 5: Which are the geometric characteristics of the roller?

Response 5: The geometric characteristics of the roller is described in line 105: “The roller is made up of material GCr15 with diameter 35mm and 2.5mm long.”

Comment 6:On line 116, I think it would be interesting to put Chrome instead of Cr at the beginning of the second sentence.

Response 6: Thank you for your careful work. We have put Chrome instead of Cr at the beginning of the second sentence.

Comment 7: Table 2 shows the mean of the 5 values taken on the different specimens, don’t it? If it is like this, I think is also necessary to declare the errors or the typical deviation of these values. 

Response 7: We are very sorry for our incorrect writing, we have rewritten the values, please see the lines from 123 to 125.

Comment 8: Table 2 and Figures 4 and 5, show the same information. I think that one of them (i.e. Table 2), is not necessary. But in figures 4 and 5 it is also necessary to put the error bars. The same happen with Table 3 and figures 7 and 8; and Table 4 and figure 9.

Response 8: Thank you very much,  in order to illustrate residual stress's change with the increase of contact stress or with the change of number of rolling pass cycles, so we use Table 2 and Figures 4 and 5.

Comment 9: In cases of curves of graphs 4 and 5, it would be interesting to know the numerical fitting level. For example, the curve for 2 cycles in figure 4 fits worse than all the others. The same for Figures 7 and 8.

Response 9: In figure 4 the coefficient adjusted R-Squared of 1 cycle, 2 cycles, 3 cycles, 5 cycles and 8 cycles, were 0.96629, 0.90568, 0.8801, 0.89718 and 0.96044, respectively. In Figure 7 the coefficient adjusted R-Square of 1 cycle, 2 cycles, 3 cycles, 5cycles and 8 cycles, were 0.62073, 0.89093, 0.97115, 0.99903 and 0.92324, respectively. In figure 8, the coefficient adjusted R-Square of 1 cycle, 2 cycles, 3 cycles, 5 cycles and 8 cycles, were 0.76298, 0.87179, 0.59006, 0.83579 and 0.80512, respectively.

Comment 10: In lines 154-156, a new element is introduced in the analysis (the cost of the process), to make a decision, but it is not explicitly stated how costs influence. In other words, there is no cost comparison for each process, nor is it stated how those costs are calculated.

Response 10: Thank you very much.  Shot peening and rolling are effective ways for strengthening part's surface. Shot peening requires a lot of pellets, and the shot peened surface usually need to be cleaned.

Comment 11: In figure 7, curves for 1 and 2 cycles does not seems similar to the rest of the curves. Can you explain why do you think it happens? In principle Residuals stresses and hardness have some relation, and in case of residuals stresses the fit of the curves that you have presented are very similar.

Response 11: At the beginning of the rolling,the applied force smoothes out the irregularities of the surface by forcing the metal to spread and flow plastically from the peaks of the asperities to fill the valleys, after rolling the surface were charged, so the  curves for 1 and 2 cycles does not seems similar to the rest of the curves.

Comment 12: On line 198, you declare that the Ra of initial pieces is 3.079 μ I think that in the same line of the previous comments, if it is the mean value of different measurements, error have to be declare.

Response 12: We are very sorry for our incorrect writing, the Ra is not the mean value of different measurements.

Comment 13: There is something very important in this kind of study demonstrate by many recent studies, like the ones listed below. The roughness in the pieces before rolling is very important factor, so if this parameter changes for the different specimens it could be a problem. So, how can the authors justify not having taken this parameter into account as a process variable?Jerez-Mesa, Ramón, et al. "Comprehensive analysis of surface integrity modification of ball-end milled Ti-6Al-4V surfaces through vibration-assisted ball burnishing." Journal of Materials Processing Technology 267 (2019): 230-240.Jerez-Mesa, Ramón, et al. "Topological surface integrity modification of AISI 1038 alloy after vibration-assisted ball burnishing." Surface and Coatings Technology349 (2018): 364-377.

Response 13: Thank you very much, we have rewritten the sentence, please see the lines from 226 to 228.

Comment 14: The last comment is about the novelty of this paper. How could you differentiate your study of the rest recently published about almost the same topic?

Response 14: In this paper, the rolling test of 210Cr12 axle is carried out, the rules and mechanism of rolling strengthening of this kind of material are revealed, and the rolling strengthening process parameters of 210Cr12 axle parts are put forward, which provides theoretical basis and technical support for the practical application of surface rolling strengthening technology.

    Overall, thank you for the professional review work on our article! Thanks for the positive reviews on our articles. Thank you very much.

Reviewer 2 Report

The article entitled „Research on Mechanical Properties of Cr12 Shaft's Surface Processed with Rolling” is interesting due to the processing of this type of alloys by burnishing and  it is an important aspect of the process of producing elements from this type of material.

However, the form and method of preparing materials for publication is very chaotic. The burnishing process is a very unstable process, because it depends on many factors that may be change, in this case it is necessary to carefully describe all the factors affecting the values of the results obtained, therefore the article requires thorough rewording.

The main drawback is the results mixed with the settings of measurement and sample preparing (line159, 160).

I kindly suggest set in order the article according to the scheme: detailed description of the process and its parameters, description of the samples and their characteristics, including parameters of previous turning, description of measuring devices and theirs setting parameters, research results.

The manner of preparation and conduct of tests should be described in detail, and in particular: the condition of the samples. In the article is presented that the samples were forged (line 94) or quenched and tempered (line 156). These processes have a significant impact on the metallographic structure of the material, in particular on the size, shape and arrangement of grains, and the physical properties of the material. The article should contain precise information on what the sample material structure looks like and what its physical properties are, as this has a significant impact on the machining results.

Measuring equipment should be described in terms of the method and conditions of measurement, the description should be included data about the range of measurement uncertainty (lack for all devices). In addition, the setting values of measurement devices are missing , e.g. for roughness measurements it is not known about: sampling length, evaluation length, type of filter, e.t. as well as the standards by which the measurements were made.

Measurements of micro-hardness stresses and roughness both on the surface and inside the material should be also made for the sample before processing and presented in the work. All results should be supplemented with range of data spread or standard deviation. For roughness, the Ra parameter is an average parameter and is of limited use in determining the effects of machining. In this case, the geometric surface structure is better assessed by comparing the surface profile before and after processing.

Contact stresses have been calculated according to the Hertz formula (line 109). The formula and input data by which these stresses have been calculated should be included in the paper. It is important because these stresses depend on many factors, among others the shape and dimensions of the rollers. Moreover, the article should include a detailed drawing of the burnishing roller, as its shape and dimensions have a significant impact on the results of the burnishing process.

The article should also specify the place of measurements on the sample. This is due to the fact that for soft materials, a "wave" of outflowing material forms in front of the roller and moving with roller, which causes changes to the properties of the machined surface to along the burnishing path.

The conclusions in their current form are very illegible.

The important achievements may be highlight by writing them in points.

The text should be checked by the person for whom English is native language.

Detail remarks:

Title: The process has presented in the article in the literature is determined as a burnishing or low plasticity cold rolling. This also applies keywords.

Figure 1. The drawing is too simple and does not include significant phenomena occurring during burnishing. It may be supplemented among others with a zone of changes in: the hardness , stress, plastic deformation, elastic deformation, etc.

Line 64. What formula? The text should be supplemented by this formula.

Line 64-66. The sentence is incomprehensible.

Line 69. Mieczyslaw it is first name.

Line 104. 4mm - This is probably incorrect value.

Fig 3. This device is commonly known and no carry on any significant information, I suggest replace it to drawing of burnishing roller.

Tables 2-4 and figures 4-9 should be supplemented to standard deviation or range of spread of measurement results.

Line 164. The depth of stresses determined as 0.2, what did criteria this value based on?

Author Response

    Thank you very much for your comments and suggestions. We have studied the valuable comments from you carefully, and tried our best to revise the manuscript. The point to point responds to the comments are listed as following:

Comment 1: Title: The process has presented in the article in the literature is determined as a burnishing or low plasticity cold rolling. This also applies keywords. 

Response 1: Thank you for your careful work. We have rewritten the keywords, and put rolling instead of rolling process.

Comment 2: Figure 1. The drawing is too simple and does not include significant phenomena occurring during burnishing. It may be supplemented among others with a zone of changes in: the hardness, stress, plastic deformation, elastic deformation, etc.

Response 2: The principle of rolling for surface strengthening is shown in Fig. 1, so we think it is an important figure.

Comment 3: Line 64. What formula? The text should be supplemented by this formula.

Response 3: Thank you for your careful work. We have rewritten the sentences, please see the lines from 64 to 65.

Comment 4: Line 64-66. The sentence is incomprehensible.

Response 4: We are very sorry for our incorrect writing. We have rewritten the sentences, please see the lines from 65 to 69.

Comment 5: Line 69. Mieczyslaw it is first name.

Response 5: Thank you for your careful work. We have corrected the error.

Comment 6: Line 104. 4mm - This is probably incorrect value.

Response 6:  Thank you for your careful work. We have rewritten the sentences: The roller is made up of material GCr15 with diameter 35mm and 2.5mm long.

Comment 7: Fig 3. This device is commonly known and no carry on any significant information, I suggest replace it to drawing of burnishing roller.

Response 7: The iXRD stress analyser and specimen are shown in Fig. 3, so we think it is an important figure.

Comment 8: Tables 2-4 and figures 4-9 should be supplemented to standard deviation or range of spread of measurement results.

Response 8: We are sorry for not describing the errors, we have rewritten the values, please the lines from 126 to128, and the lines from 180-182.

Comment 9: Line 164. The depth of stresses determined as 0.2, what did criteria this value based on?

Response 9: Thank you for your careful work. We have rewritten the sentences, please see the lines from 174 to175.

    Overall, Thank you again for the valuable suggestions to improve the quality of our manuscript. Thank you very much.

Reviewer 3 Report

The article deals with the effects of rolling parameters on surface residual stress, microhardness, surface roughness. 

However some suggestion should be taken into account to improve the quality of the paper: 

1) fig 6 and 7 are not clear and paragraph break simbol is present in the picture

2) how many specimens have been tested?

3) no error or standard deviation is reported in the results (both in tables and figures) 

4) It would be interesting to investigate the surface microstructures of the rolled surface at different contact stresses and number of rolling passes

Author Response

    Thank you very much for your comments and suggestions. We have studied the valuable comments from you carefully, and tried our best to revise the manuscript. The point to point responds to the comments are listed as following:

Comment 1: fig 6 and 7 are not clear and paragraph break simbol is present in the picture.

Response 1: Thank you for your careful work. We have corrected the figures.

Comment 2: how many specimens have been tested?

Response 2: 5 specimens have been tested.

Comment 3: no error or standard deviation is reported in the results (both in tables and figures).

Response 3: We are very sorry for our incorrect writing, we have rewritten the values, please the lines from 126 to128, and the lines from 180-182.

Comment 4: It would be interesting to investigate the surface microstructures of the rolled surface at different contact stresses and number of rolling passes.

Response 4: Thank you for your careful work. We have rewritten the conclusion, please see the lines from 254-255. 

    Overall, Thank you again for the valuable suggestions to improve the quality of our manuscript. Thank you very much.

Round 2

Reviewer 1 Report

Thank you for answer all the comments.

Author Response

Thank you very much again. Thanks for the patience and help to improve the quality of our manuscript. Thank you.

Reviewer 2 Report

Thank you for responding to the review. After reviewing this answer, I found that it contained only answers for detailed remarks, whereas  lack the answers for general comments.

The results presented in the paper from a general point of view are typical for burnishing process and there are commonly known. In this form do not bring anything new in science.

However, the essence of this article should be detail research for a specific material. In this case, the researches must be very carefully described in terms of how they are conducted as well as the results obtained (accuracy, dispersion , etc.). Failure to comply with these conditions means that it is impossible to verify the results presented, what it means, these results are not of  useful at all. The remarks which I presented in the previous review aimed to supplement the presented research results to the level at which these could be useful for other researchers. Unfortunately, the article text has not been sufficiently corrected in this respect.

Author Response

    We are very sorry for the lack of answers for general comments, we have studied the general comments( round 1) and review report ( round 2) carefully, and according to the suggestions, we carefully revised the manuscript again, the errors were corrected, the other changes in the manuscript were highlighted using red colored text. 

    Overall, thank you for the professional review work on our article! Thanks for the positive reviews on our articles. Thank you very much.

Round 3

Reviewer 2 Report

The presented Hertz model is a two-dimensional model and the values calculated apply an range of elastic deformation. However, plastic deformation dominates during burnishing process. In this case the outline of the burnishing roll could be helpful to determinate the stresses in the crush zone may be specify more precisely.

There is still no information about the dispersion of research results at work. This is important information regarding the stability of the burnishing process. It can be seen on the charts that some points deviate significantly from the curve. Due to the lack of the above information, it is difficult to say whether this results from a large dispersion of results or occur additional phenomena and this causes lack of a proper fit of the curve to the process.

On line 222, the sampling length (it called also as  a cut-off length) is the wrong value. According to the ISO standard these values may be ..., 0.25, 0.8, 2.5, .... Moreover, the evaluation length can be included one or more sampling lengths.

Author Response

    Thank you very much for your comments and suggestions. We have studied the valuable comments from you carefully, and tried our best to revise the manuscript.

    1. We added an two-dimensional map of the roller, please see the Fig.2.

    2. In this paper, Fig.4 reveals the relationship between residual stresses and contact stresses, Fig.5 reveals the relationship between residual stresses and the number of rolling pass cycles, Fig.7 reveals the relationship between microhardness and the contact stresses, Fig.8 reveals the relationship between microhardness and the number of rolling pass cycles, and these figures were only used to illustrate the changing trend rather than predictions.

    3. We are very sorry for our incorrect writing, we have rewritten the values, please see the lines from 223 to 224.

    Overall, thank you for the professional review work on our article! Thanks for the positive reviews on our articles. Thank you very much.

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