Impact of the Process Parameters, the Measurement Conditions and the Pre-Machining on the Residual Stress State of Deep Rolled Specimens
Round 1
Reviewer 1 Report
In this research work a study on the residual stresses of specimens submitted to deep rolling is presented. The study is performed on an AISI 4140 steel that has been previously submitted to thermal treatment. The study has been done by using X-Ray diffraction, and in some cases the measurements have been done in two different laboratories using different types of X-Ray diffractometers. The results presented in the paper are original and they deserve to be published. I indicate some mistakes that can be corrected in order to improve the quality of the manuscript.
1. Lines, 151, 234, 237, 282, 295, 471. In these cases the word “chapter” is used instead of “section”.
2. Figure 4 b. The caption “ surface distribution in x direction (mm)”, is it OK?
3. Figure 5 b. The caption “ surface distribution in x direction (mm)”, is it OK?
4. Figure 7 b. The caption “ surface distribution in x direction (mm)”, is it OK?
5. Line 483. It is said: “ In this paper was discussed..” In my opinion it must be: “In this paper it was discussed…”
Author Response
Response to Reviewer 1 Comments
Dear reviewer,
Thank you very much for considering our manuscript. Enclosed, you will find the answers to your comments.
Point 1: Lines, 151, 234, 237, 282, 295, 471. In these cases the word “chapter” is used instead of “section”.
Response 1: The suggested correction will be done.
Point 2: Figure 4 b. The caption “surface distribution in x direction (mm)”, is it OK?
Response 2: The caption “surface distribution in x direction (mm)” refers the direction of the measurement path, which for the surface residual stress measurements (Figures 4, 5, 6 and 7) was defined perpendicular to the DR trace, i.e. in x direction (see Figure 2 b)). The residual stress direction (longitudinal or transverse to the DR trace) was plotted as Figure a) – longitudinal and Figure b) transverse. Therefore, we consider the caption is proper.
Point 3: Figure 5 b. The caption “ surface distribution in x direction (mm)”, is it OK?
Response 3: See response 2
Point 4: Figure 7 b. The caption “ surface distribution in x direction (mm)”, is it OK?
Response 4: See response 2
Point 5: Line 483. It is said: “ In this paper was discussed..” In my opinion, it must be: “In this paper it was discussed…”
Response 5: The suggested correction will be done.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In the article entitled "Impact of the process parameters, the measurement conditions and the pre-machining on the residual stress state of deep rolled specimens" the Authors investigated the influence of surface preparation combined with deep rolling process on residual stresses in the material near surface region. The article is written in a very good way and guide the readers. The results are shown very clearly and discussed accurately.
In my opinion this article is worth ublishing after very minro corrections, as follows:
1. Page 2, line 91: Please give more detail information what kind of polymer was used for quenching.
2. Page 3, line 108: Please replace word "grinded" by "ground".
3. Please describe more accurately the motivation of your work. It is clear from the article, that surface preparation influences residual stresses, however there is no single information what is the consequence of high residual stress in the material and why it is important to investigate this issue.
Considering all above mentioned observation I reccomend to publish this article after minor corrections.
Author Response
Response to Reviewer 2 Comments
Dear reviewer,
Thank you very much for considering our manuscript. Enclosed, you will find the answers to your comments.
Point 1: Page 2, line 91: Please give more detail information what kind of polymer was used for quenching.
Response 1: In the available material certificate, there is no indication of the type of polymer used during quenching.
Point 2: Page 3, line 108: Please replace word "grinded" by "ground".
Response 2: The suggested correction will be done.
Point 3: Please describe more accurately the motivation of your work. It is clear from the article, that surface preparation influences residual stresses, however there is no single information what is the consequence of high residual stress in the material and why it is important to investigate this issue.
Response 3:
In the introduction section, line 36, the following text will be added:
“The main advantage of deep rolling when compared with e.g. the even commonly applied shot peening process, is that along the induced cold worked layer, deep rolling generates deeper compressive residual stress (RS) field and achieves a smoother surface in contrary to shot peening. The controlled generation of compressive residual stresses is crucial for the fatigue strength of the treated material, as compressive residual stresses can prevent crack initiation and can retard crack propagation.”
Additionally, the importance of compressive residual stresses was commented already in section 3.4, lines 400-406 as follows:
“It is important to point that the information for the RS depth distribution is in general crucial for the prediction of the fatigue behavior of the treated parts and cannot be substituted only by surface RS profiles determination. The so-called stress impact depth is an important characterization parameter, as the presence of deeper, not only high as amount, compressive RS can serve for retarding the propagation of existing cracks and can prevent cracks formation even by the presence of tensile RS on the surface. The definition “crack arrest/closure” describes this phenomenon [18].”
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors have conducted a detailed study on finding the impact of process parameters, measurement conditions and pre-machining on residual stress of DR rolled specimens. Overall, the study looks interesting.
Here are some points need to be improved/modified:
Page 1 line 24: 'analyze/analyse' instead of 'analyses'
Page 2 line 90: 53.5% instead 53,5%
Page 2 line 92: Please share the reason behind austenitizing at 860C. Several studies showed it can be done in a range of temperatures.
Page 2 line 91: Please mention what polymer was used and its temperature while quenching.
Page 6: Please explain why two different scanning ranges were used for Seifert XRD system? The scanning ranges are ~13 degrees or 20 degree but same 120 sec time were used for data collection. How can you confirm that didn't impact the data? On the other hand, for Panalytical system, the data collection time was significantly more. Was that because of different detector used in those two systems?
Figure 8(a): What is the potential reason behind the steeper increase in residual stress for M12-p20 and P11-p20 specimens compared to the other two? This observed in both directions (8a and 8b).
Author Response
Response to Reviewer 3 Comments
Dear reviewer,
Thank you very much for considering our manuscript. Enclosed, you will find the answers of your comments.
Point 1: Page 1 line 24: 'analyze/analyse' instead of 'analyses'
Response 1: The suggested correction will be done.
Point 2: Page 2 line 90: 53.5% instead 53,5%
Response 2: The suggested correction will be done.
Point 3: Page 2 line 92: Please share the reason behind austenitizing at 860C. Several studies showed it can be done in a range of temperatures.
Response 3: For under-eutectoid steels (the used AISI 4140 is such one, with 0.44 % carbon), the standard hardening procedure includes heating the material at 30 °C to 50 °C above the AC3 point. For steel AISI 4140 (42CrMo S4), DIN EN 10083-3:2006 standard (page 28, table 11 — heat treatment) advise a heating range of 820 °C - 860 °C. The used material was a standard one and there was no particular intense of choosing the heating temperature of 860 °C.
Point 4: Page 2 line 91: Please mention what polymer was used and its temperature while quenching.
Response 4: In the available material certificate, there is no indication of the type of polymer used during quenching.
The cross section of the square bars, from which the specimens were milled, has dimensions of 25 mm x 25 mm. For this material size, there is no need for quenching in heated polymer, as there is no danger of inhomogeneous cooling down and the following crack formations.
Point 5: Page 6: Please explain why two different scanning ranges were used for Seifert XRD system? The scanning ranges are ~13 degrees or 20 degree but same 120 sec time were used for data collection. How can you confirm that didn't impact the data? On the other hand, for Panalytical system, the data collection time was significantly more. Was that because of different detector used in those two systems?
Response 5: Initially, the larger scanning range of 2θ 141° - 161° was used and later it was optimised to 2θ 147° - 159.5 °. The narrower scanning range delivered enough diffraction background so that a reasonable peak to background ratio was available. Comparison measurements with both scanning ranges confirmed in this case, that narrowing the scanning range does not affect the results.
The scanning time for both diffractometers differed due to different detectors used. Although, the quality and the intensity of the diffraction peaks for both systems were comparable.
Point 6: Figure 8(a): What is the potential reason behind the steeper increase in residual stress for M12-p20 and P11-p20 specimens compared to the other two? This observed in both directions (8a and 8b).
Response 6: In Figure 8a), the near-surface stress ingredients of the specimens M12, M15 and P8 are very similar. In Figure 8b), all stress ingredients but this of P11 are also very similar. There is a discrepancy of the measured stresses on the surface, which leads to redistribution of the near-surface stress field. The major difference between M12/P11 and M15/P8 in both longitudinal and transverse directions is the stress impact depth. For the specimens M15/P8 treated with higher DR pressure (40 MPa), the stress impact depth increases with 0.25 mm – 0.30 mm compared to this of specimens M12/P11 (treated with DR pressure of 20 MPa). This tendency is typical for DR. The higher DR pressure leads to higher contact pressure between tool and work-piece during processing. The higher contact pressure results in thicker plastically deformed zone, which prevents the redistribution of the stresses after releasing the DR pressure, thus expanding the residual stress impact zone deeper into the material.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
I am satisfied with author's reply. It will be good if the authors can include their comments related to my queries point 5 and 6. The readers also might have similar questions and it might be good if those are mentioned in the manuscript as well.
I think the authors just answered the queries (point 5 and 6) but didn't include their comments in the manuscript (since I don't see any highlight).
Author Response
Response to Reviewer 3 Comments
Dear reviewer,
Thank for your closer look at our manuscript. Enclosed, you will find the answers to your comments.
Point 1: I am satisfied with author's reply. It will be good if the authors can include their comments related to my queries point 5 and 6. The readers also might have similar questions and it might be good if those are mentioned in the manuscript as well.
I think the authors just answered the queries (point 5 and 6) but didn't include their comments in the manuscript (since I don't see any highlight).
Page 1 line 24: 'analyze/analyse' instead of 'analyses'
Response 1:
- Question 5 - the following text was added (lines 215 - 221):
The 2θ measurement range was optimized during the measurements and even the narrowest 2θ range delivered enough diffraction background, so that a reasonable peak to background ratio was available. Comparison measurements with all scanning ranges confirmed in this case, that narrowing the 2θ measurement range does not affect the results. The measurement time for both diffractometers differed due to different detectors used. Although, the quality and the intensity of the diffraction peaks for both systems were comparable.
- Question 6 - the following text was added (lines 447 - 451):
Typically for DR, the application of higher DR pressure leads to raising the stress impact depth in both longitudinal and transverse directions. The higher DR pressure leads to higher contact pressure between tool and work piece during processing. The higher contact pressure results in thicker plastically deformed zone, which prevents the redistribution of the stresses after releasing the DR pressure, thus expanding the residual stress impact zone deeper into the material.
- Page 1 line 24: 'analyze/analyse' instead of 'analyses' – the correction was done.
Author Response File: Author Response.pdf
