Change in Time of the Value of Dry and Lubricated Friction Coefficients for Surfaces Generated by Different Processing Methods

Round 1

Reviewer 1 Report

The paper describes an empirical study of the time evolution of the friction of a range of surfaces generated by different processing methods under dry and lubricated conditions. The topic of the paper will be of interest to readers of the journal. However, the weakness of the paper is that the nature of the lubrication has not been considered. For example, the onset of hydrodynamic lubrication depends on the relative heights of the asperities and the lubricating film. I have the following additional comments:

·       The term wet friction is used throughout the paper. The authors should use lubricated friction.

·       The term modelling is used throughout the paper. It is actually a non-linear correlation of the data.

·       Lines 31-67 and 140-146 are trivial for readers of the journal. I suggest that they are deleted.

·       It is not obvious that the finite element modelling adds to understanding the data.

·       Line 360: hardness should be quoted in SI units.

·       Line 478-480: The following statement is made: As previously mentioned, the time variation of the size of the friction coefficient can be correlated with the time variation of the value of the roughness parameter Ra. I could not find any data that substantiated this statement.

·       Line 513: The following statement is made: The friction coefficient μ is the main size used…. The term parameter would be more appropriate than size.

Author Response

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Thank you!

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to the Author:

In this paper, the research investigates the impact of different processing methods on the friction performance of mechanical parts, and determined the test results of the experiment through an empirical mathematical model. I refuse to recommend publication of the manuscript until it is revised. The revisions are noted below:

1.      In the introduction, you need to connect the state of the art to your paper goals to inform readers of the research background accurately, and you should add relevant references in the first paragraph to enrich the background.

2.      In section 2.1, the article elaborates on the influence of roughness parameter Ra on the friction process, and the author can further explain the influence of different processing techniques and parameters on roughness parameter Ra.

3.      In section 2.2, the experimental methods and parameters could be described in more detail, as different experimental parameters such as cylinder radius and F_n significantly impact the experimental results.

4.      The author can merge pictures 8 and 9 for the convenience of the reader.

5.      Please provide the specific parameter design in the simulation process in the attachment, so that readers can copy your experimental process.

6.      The very latest references about the tribological properties (e.g., Composites Part B 263 (2023) 110833; Tribology International 181 (2023) 108295) may be of interest to the authors for citations.

7.      In the discussion, a more detailed discussion should be conducted on the impact of H20-type hydraulic oil on the friction process under wet friction conditions, in order to compare it with dry friction conditions.

Moderate editing of English language required

Author Response

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Thank you!

Author Response File: Author Response.docx

Reviewer 3 Report

Authors suggested that the experimental research, by considering account the possible influence exerted by several factors on the evolution over time  of the size of the friction coefficient. The article is very interesting. 

1) Revise the title. Title is too long.

2) In the framework of the experimental research, the results of which are presented in this paper, the outer cylindrical surfaces of  some test steel samples were obtained by different processing methods, such as turning, grinding, ball and diamond tips burnishing, and vibroburnishing.

Check the language. Clarify the points.

3) Conclusions are very long.  Focus on relevance conclusion. 1.       All conclusions must be convincing statements on what was found to be novel, impactful based on strong support of the data/results/discussion.

4) Add citations to the first paragraph of introduction section.

5) Provide citation for equation 1, 2

6) Justify for the point  "there is an increase in the size of  the friction coefficient µ, later the intensity of the increase in the size of the friction coefficient µ decreases."

7)  Check for typo through out the manuscript.

8) Authors concluded that "The experimentalresults revealed an increase in the value of the friction coefficient, under conditions of wet friction, by 48-205 %" How this data has been computed?

9) Reference style should be checked throughly.

Author Response

Please find attached the answers. 

Thank you!

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

None

None

Reviewer 2 Report

Thanks for a positive response. All the questions have been satisfactorily addressed, so an acceptance of this promising work is recommended

Reviewer 3 Report

This revised manuscript can be accepted for publication.