Improved Microstructure of 316LN Stainless Steel Performed by Ultrasonic Surface Rolling

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper addresses an important topic, as optimizing deep rolling processes for roller bearings is a current focus of research. However, the introduction is rather brief and lacks sufficient context and references. In particular, it would be valuable to compare ultrasonic surface rolling with hydrostatic deep rolling, since both techniques share certain similarities. In the field of roller bearings, deep rolling and turn-rolling are well-established processes; see for example: https://doi.org/10.1108/ILT-07-2018-0254. But it can also regard ongoing research like deep rolling for Tailored Forming machine elements, I think there is some more research to be included. 

Furthermore, the test matrix and the residual stress results presented early in the paper are misplaced. These should be moved to the Methods section (for the experimental procedure) and the Results section (for the achieved residual stresses), respectively.

Regarding language and clarity, some phrasing needs improvement. For instance:

• Page 3, line 78:

  • Original: “AutoMATE II X-ray diffractometer was employed to detect surface residual stress. It employed the fixed 𝛹0 method for scanning, with the 𝛹0 angle selection provided by the device's default settings, comprising a total of 7 values.”

  • Suggested: “The AutoMATE II X-ray diffractometer was used to measure surface residual stress. It utilized the fixed 𝛹₀ method for scanning, with the 𝛹₀ angles automatically selected according to the device’s default settings, comprising a total of seven values.”

• Line 87:

  • Original: “it is necessary to grind them sequentially tuusing sandpapers”

  • Suggested: “it is necessary to grind them sequentially using sandpapers.”

Figure 2 is visually appealing, but the scale bars—especially in Figure 2i—are too small and should be enlarged for clarity.

In the Results section, the paper presents microhardness measurements over depth as well as SEM and EBSD images. However, the discussion of residual stresses—introduced early as a key focus—is not followed up sufficiently. This aspect needs to be addressed in more detail to align with the paper’s stated goals.

Finally, the conclusion is too brief. It would benefit from a broader discussion and synthesis of the findings to ensure a well-rounded ending to the paper.

Summary: This is a promising paper on an important and relevant topic. However, it currently loses focus by placing too much emphasis on SEM/EBSD images while neglecting the residual stress results that are initially highlighted as central. Improving structure, depth of analysis, and linguistic clarity will significantly enhance its impact.

Comments on the Quality of English Language

In some parts the english language needs improvement. I put some examples in my comments to the authors. 

Author Response

1. Introduction Enhancement

Comment:

"The introduction is brief and lacks context. Suggest comparing ultrasonic surface rolling (USRP) with hydrostatic deep rolling, and cite more foundational studies (e.g., DOI:10.1108/ILT-07-2018-0254)."

Response:

We have expanded the introduction by:

1. Adding a technical comparison between USRP and hydrostatic deep rolling (Lines 37):

   "Ultrasonic rolling is different from hydraulic deep rolling. While hydrostatic deep rolling relies on fluid pressure to induce deformation, USRP combines static force with ultrasonic vibrations (20–40 kHz), enabling deeper stress penetration and finer grain refinement. Both techniques improve fatigue resistance, but USRP achieves higher dislocation density due to its high-frequency impacts."

2. Adding a technical comparison of the influence of residual stress changes on fatigue life(Lines 47):

Florian Pape. proposed a novel bearing fatigue life prediction model that considers subsurface compressive residual stresses, focusing on the surface properties of rolling contact machine elements. Bearings were machined using hard turning, hard turning followed by deep rolling, and a combined turn-rolling process to study the effect of residual stress changes on fatigue life. The results showed that processing methods involving deep rolling significantly reduced surface roughness and introduced beneficial compressive stresses, increasing the L10 fatigue life of bearings by a factor of 2.5, thereby providing an effective approach to improving resource efficiency.

3. Citing additional references, including:

   The recommended bearing study (DOI:10.1108/ILT-07-2018-0254) on turn-rolling. et al.

2. Structural Reorganization

Comment:

"Residual stress data in Section 1 should be moved to Methods/Results."

Response:

We sincerely appreciate your thoughtful suggestion regarding the organization of the residual stress data. While we fully recognize the merit of relocating this information to the Methods/Results sections for improved structural clarity, we have chosen to retain Table 1 in the Introduction for the following technical and pedagogical reasons:

Conceptual Framing: The orthogonal array results serve as critical motivation for the study by immediately demonstrating the parameter-response relationships that justify our experimental approach. Presenting this data upfront helps readers better appreciate the Taguchi method's rationale before encountering the technical details of implementation.

Consistency with Literature. Similar structural approaches are adopted in: Zhao et al. (Results in Physics, 2017) . Tan et al. (J. Mater. Eng. Perform., 2019)

3. Language Clarity

Specific Edits:

1. Line 78 (X-ray diffraction):

   Revised to: “The AutoMATE II X-ray diffractometer was used to measure surface residual stress. It utilized the fixed ?₀ method for scanning, with the ?₀ angles automatically selected according to the device’s default settings, comprising a total of seven values.”

2. Line 87 (Sample prep):

   Corrected typo: "sequentially using sandpapers".

3. Figure 2i:

  The entire Figure 2 has been enlarged to improve the clarity of Figure 2i.

4. Results & Discussion Improvements

Comment:

"Residual stress analysis is underdeveloped vs. SEM/EBSD focus."

Response:

1. Section 3.3 has been added, with a focus on the analysis of residual stress.
2. Expanded conclusion now discusses:

Conclusion 3 and Conclusion 4 have been added.

 “(3) When the rolling experiment parameters of the sixth group are selected (lathe speed of 140 r/min, rolling amount of 0.03 mm, feed rate of 0.15 mm/r, and number of rolling passes of 5, the surface residual compressive stress reaches its maximum value, approximately 1453.43 MPa. At this time, relatively speaking, not only can a relatively fast processing rate be achieved, but also the maximum residual stress and a good pro-cessing effect can be obtained.”

“(4) The surface roughness of specimens after ultrasonic surface rolling processing (USRP) can be reduced by up to 85%, demonstrating the potential application of USRP in nuclear pipeline systems where surface roughness would otherwise accelerate corrosion.”

5. Terminology Consistency

Comment:

"Why use 'TC' instead of 'TB' for twin boundaries?"

Response:

Corrected to standard "TB" throughout.

6. English Language Polishing

All passive-voice constructions (e.g., "was polished") were standardized.

Reviewer 2 Report

Comments and Suggestions for Authors

The article is devoted to the study of the effect of ultrasonic rolling of the surface of a round sample made of 316LN stainless steel on improving the microstructure and increasing the microhardness of the surface. The article contains the results of experimental studies of surface treatment using the Taguchi method. The article may be of interest to readers.

Notes:

1. It is advisable to give a brief description of the idea of the Taguchi method, since not all readers are familiar with this method.
2. On page 6 (and further in the text of the article) there is a description of sample No. 26 (text and figure 3) and a reference to table No. 1 is indicated, but table 1 does not contain sample No. 26. It is necessary to bring it into line.
3. In references to literature, it is advisable to expand the geography of the authors, similar studies were conducted all over the world.

Author Response

Comment 1:

"It is advisable to give a brief description of the idea of the Taguchi method, since not all readers are familiar with this method."

Response:

We agree with the reviewer’s suggestion and have added a concise explanation of the Taguchi method in the Introduction section. The revised text reads: "The Taguchi method is a statistical approach designed to optimize process parameters with minimal experimental trials. It employs orthogonal arrays to systematically vary parameters  and analyzes signal-to-noise (S/N) ratios to identify optimal conditions. This method is cost-effective and accounts for parameter interactions, making it ideal for industrial applications where resource efficiency is critical."

Comment 2:

"On page 6 (and further in the text of the article), there is a description of sample No. 26 (text and Figure 3) and a reference to Table 1 is indicated, but Table 1 does not contain sample No. 26. It is necessary to bring it into compliance."

Response:

We apologize for this oversight. Sample No. 26 represents the optimal parameter set derived from Taguchi analysis (220 rad/min, 0.11 mm rolling space, 0.2 rad/min feed rate, 5 passes), which was validated post-orthogonal experiments. To avoid confusion:

1. Table 1 has been updated to include Sample No. 26 (highlighted in bold) with its SRCS value (−1252 MPa, consistent with the highest S/N ratio in Taguchi results).
2. Figure 3 and related text now explicitly state that No. 26 is the optimized case, distinct from the L25 orthogonal array trials.

Revised Table 1 Excerpt:

Experimental No.	Lathe speed (rad/min)	Amount of rolling (mm)	Feed rate (rad/min)	Rolling passes	SRCS (MPa)
26	220	0.11	0.2	5	-1252

 

Comment 3:

"In references to literature, it is advisable to expand the geography of the authors, similar studies were conducted all over the world."

Response:

We have expanded the literature review to include key international studies on USRP and gradient materials, ensuring global relevance. Covering regions such as Hong Kong, China; Germany; the United States; India; Turkey, etc.

 

1. Bernoulli, D., Cao, S. C., Lu, J., & Dao, M. Enhanced repeated frictional sliding properties in 304 stainless steel with a gradient nanostructured surface. Surface & Coatings Technology, (2018).339, 14-19. https://doi.org/10.1016/j.surfcoat.2018.01.081
2. Pape, F., Maiss, O., Denkena, B., & Poll, G. Enhancement of roller bearing fatigue life by innovative production processes. Industrial Lubrication and Tribology, (2019). 71(3), 370-377. https://doi.org/10.1108/ILT-07-2018-0254
3. Jayalakshmi, M., Huilgola, P., Bhat, B. R., & Bhat, K. U. Insights into formation of gradient nanostructured (GNS) layer and deformation induced martensite in AISI 316 stainless steel subjected to severe shot peening. Surface & Coatings Technology, (2018). 344, 295-302. https://doi.org/10.1016/j.surfcoat.2018.03.028
4. Ghosh, S., Bibhanshu, N., Suwas, S., & Chatterjee, K. Surface mechanical attrition treatment of additively manufactured 316L stainless steel yields gradient nanostructure with superior strength and ductility. Materials Science & Engineering A, (2021). 820, 141540. https://doi.org/10.1016/j.msea.2021.141540
5. Ralls, A. M., Baldwin, C., She, Y., Wang, X., Jiang, Y., & Menezes, P. L. Assessing the tribo-corrosion resistance of surface nanostructured stainless-steel. Surface & Coatings Technology, (2024).483, 130755. https://doi.org/10.1016/j.surfcoat.2024.130755

Reviewer 3 Report

Comments and Suggestions for Authors

The paper is devoted to investigating the affect of ultrasonic surface rolling processing on the microstructure and hardness parameters of 316LN stainless steel. The authors have performed wide variation of rolling parameters (Lathe speed, amount of rolling, feed rate, rolling passes) and investigated the grain structure and hardness. The optimal combination of rolling parameters was selected. The paper provides detailed data, it is very well organized. 

However some mistakes or typos are to be corrected to improve the paper perception.

1) Line 19 "passes rolling passes" - please check, probably just "rolling passes"

2) Line 22 LAGBs abbreviation is introduced for the first time without explaining the meaning

3) The lines "Average S/N-1", "Average S/N-2", etc. are not discussed in the text neither even explained.

4) Lines 64 and 65. Please specify the sequence of operations. Usually the oil and impurities are cleaned first by the acetone and then the oxide layer ie removed. This sequence is inversed in the description given at lines 64-65.

5) Please provide more detailed description of how the cross section was prepared and measured. How was the sample cut? How was it positioned for different measurement?

6) Lines 123-125 the following sentence is badly organized "The most significant alterations occurred in the PV and RMS values, with reductions of 85.0% and 53.78% for No.15, respectively".

What does "respectively" refer to? I believe it is better to use the following:

"The most significant alterations occurred in the PV and RMS values for No.15, with reductions of 85.0% and 53.78% , respectively"

7) Line 127 "This occured...". What does "This" refer to? The previous sentence (Lines 125-127) includes two statements:

First is a a significant alteration in the workpiece's surface profile following URSP treatment

Second is that the distinctive features of peaks and troughs remain incompletely eradicated.

It is better to specify which of two is discussed in the next sentence, or maybe the both.

8) Why are the twin boundaries are abbreviated as TCs not TBs?

Finally I believe the paper can be published as soon as the authors provide the requested comments of improvements.

Comments on the Quality of English Language

1) Line 31 "failure modes come from often the combination" - please check, probably it should be "failure modes often come from the combination"

2) Line 64 "was shown in Table 2" - usually "...is shown..." is used

3) Lines 88, 92, 93. Usually passive voice is used when describing the sample preparation. For ex. "was polished", "was etched". The sentence like "And then polished them" is a very bad style.

4) Line 108 "were quantitatively described the characteristic alterations" - please check, probably it should be "quantitatively described the characteristic alterations"

 

Author Response

1. Language and Typographical Corrections

Comment 1: Line 19 "passes rolling passes" - please check

Response: Corrected to "rolling passes" (Line 19).

Comment 2: Line 22 LAGBs abbreviation introduced without explanation

Response: We have added definition: "low-angle grain boundaries (LAGBs, misorientation <15°)" (Line 22).

Comment 3: "Average S/N-1", "Average S/N-2" not explained

Response: Added in Section 1.3: "The signal-to-noise (S/N) ratios were calculated for each parameter combination, where S/N-1 corresponds to surface roughness optimization and S/N-2 to microhardness maximization."

Comment 4: Lines 64-65 sequence of cleaning operations unclear

Response: Revised to:"Specimens were sequentially cleaned in acetone (10 min ultrasonic bath) to remove oils, then etched in aqua regia (HCl:HNO₃ 3:1) for 30 s to eliminate oxides."

Comment 5: Cross-section preparation details insufficient

Response: Added in Section 2.1: "Cross-sections were prepared by wire-EDM cutting perpendicular to the rolling direction, mounted in conductive resin, and polished to 0.05 μm finish. Measurements were taken along the depth axis at 50 μm intervals."

2. Technical Clarifications

Comment 6: Lines 123-125 sentence restructuring

Response: Revised to: "For sample No.15, the most significant alterations occurred in PV (85.0% reduction) and RMS (53.78% reduction) values."

Comment 7: Line 127 "This" reference unclear

Response: Clarified as: "This incomplete eradication of surface features occurs because..."

Comment 8: Twin boundaries abbreviation

Response: Standardized to "TB" throughout the manuscript.

3. English Language Polishing

All suggested improvements were implemented:

1. Line 31: Revised to" Failure modes often come from synergistic effects "
2. Line 64: Corrected to "is shown in Table 2"
3. Lines 88-93: The sample preparation process was described using passive voice constructions.
4. Line108: Corrected to“were used to quantify described the characteristic alterations in surface morphology”

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The reply is fine, the manuscript is mainly fine. You may refer the study about deep rolling to: Pape et al. .... and remove Florian. 

and I suggest to modify the sentence "Failure modes often come from synergistic effects of environment, material properties, and residual stress" page 1 line 32 to: 

"Failure modes are often influenced by synergistic effects of environment, material properties, and residual stresses" --- as each can be positive as negative.

 

 

Author Response

Response to Reviewer Comments

 

Manuscript ID: metals-3557799

Title: Improved microstructure of 316LN stainless steel performed by ultrasonic surface rolling

Authors: Likun Jiang, Xingwang Feng, Huanchun Wu, Meng Zhao, Guosheng Su, Bin Yang*

Dear Reviewer,

Thank you for your valuable comments and constructive suggestions on our manuscript. We have carefully addressed all the issues raised, and the detailed responses are provided below.

1. Reference Revision

As suggested, we have removed the citation of “Florian”.

2. Sentence Modification

We fully agree with your suggestion regarding the phrasing of the synergistic effects. The original sentence: "Failure modes often come from synergistic effects of environment, material properties, and residual stress."has been revised to: "Failure modes are often influenced by synergistic effects of environment, material properties, and residual stresses."

We appreciate your insightful feedback, which has significantly improved the precision of our manuscript. Please let us know if any further revisions are required. 

Sincerely,

Bin Yang

On behalf of the authors

Author Response File: Author Response.pdf