Investigation of the Surface Integrity of Q345 Steel After Nd:YAG Laser Cleaning of Oxidized Mining Parts
, Jianfeng Li 1,2, Xiujie Jia 1,2, Xing Wang 1,2, Yuan Ren 1,2 and Yuansheng Zhou 3Round 1
Reviewer 1 Report
The paper entitled Investigation on the Surface Integrity of Q345 Steel after Nd:YAG Laser Cleaning for Oxided Mining Parts, by Ma et al., is well written and structured. From my point of view, the paper shows properly the most relevant researches in this field in the Introduction, the materials and methods and results. However, some major revisions are needed:
- Be careful about the position of the Figure titles and the figures, because they should be in the same page. See Figure 5 and 10.
- The roughness parameters for the original surfaces (dirt component and matrix component) should be included in the Figure 4.This comment can be extended to the other parameters measured (microscopic morphology and micro hardness).
- Line 153. From Figure 5, I cannot see that the excessive power caused the substrate melting. Please, clarify it.
- Line 163. Do you mean matrix?
- Regarding roughness results explanation, for me it is not clear that the roughness variation is due to the existence or extraction of oxide. Maybe, they are related to substrate damages. At this point, the authors should only describe the roughness variations and then, using SEM, they should add a proper explanation. I think, they are hypothesizing about the reasons of the roughness variations too early.
- Figure 8, the images should be bigger and also they should have scale. In the current format, it is not possible to identify the peculiarities shown by the authors. They must make a new figure 8 with stereomicroscopy images.
Author Response
Dear reviewers:
Thank you for commenting on our manuscript entitled “Investigation of the Surface Integrity of Q345 Steel After Nd:YAG Laser Cleaning of Oxidized Mining Parts” (Manuscript ID: coatings-856299).
We have studied the comments carefully and have made corrections which we hope meet with approval. All the changes are marked in red in the revised manuscript.The answers to your comments are listed in the attachment.
Sincerely
Liming Wang
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript by Ma et al. describes a method for rust removal from steel surfaces. This topic has been covered several times already in the past several years. For this reason I was expecting something novel from this manuscript, or at least a very robust scientific analysis of the method. Sadly, I was left very disappointed in both aspects. The main scientific failure of the article (beyond its lack of relevance) pertains to the complete absence of analysis of the laser pulse duration.
The abstract of any research paper is its most visible section, the part that will be read most often. In the case of this manuscript, the abstract itself contains unacceptable inaccuracies and scientific nonsense.
Beginning from the first sentence in line 14: "Iron-based materials" is neither scientifically nor technologically relevant term.
"are prone to generate oxides in working environment" - If the authors meant to say that iron alloys oxidize, they certainly failed to do that correctly. And furthermore, there are iron alloys that do not oxidize.
The authors then describe some of the parameters used in the laser processing, completely ignoring the most important ones: pulse length, wavelength of the beam, and energy per pulse.
From line 21: "Based on those processing parameters, the surface roughness was reduced to 0.719μm, the surface hardness and corrosion resistance were increased about 41.0% and 52.8%, respectively." Which roughness are the authors talking about? RMS (Rq) or linear roughness (Ra)? Both are equally often used in science. Equally puzzling is the statement about hardness - it is well known that hardness can be measured in several different ways and gives different meanings to the word. This is why it has to be explicitly stated which hardness was measured: indentation, scratch, or rebound hardness? And even indentation hardness can be measured in many different ways, yielding very different results: Brinell, Vickers, Rockwell, Janka, Meyer, Barcoli, and so on.
Line 23: "What’s more, it proved the impact effect of laser in the cleaning process and verified two cleaning mechanisms, i.e., ablation effect and thermal stress effect. " - This sentence is unintelligible and completely unsuited for a scientific article. Also, never use contractions in scientific writing!
From now on I will not correct grammatical, typographical, or stylistic (for instance, "etc" must be followed by a period) mistakes. I can say, however, that the article will have to be completely re-written and checked by a professional proof-reader before a new submission is attempted. The proof-reading is not the objective of peer review.
Line 64: "Nd:YAG laser has a higher beam quality than other lasers" - This statement has no scientific value: what exactly constitutes "beam quality", how is it measured? And what are those "other lasers" to which the authors compare Nd:YAG?
Line 67: "For the mining machinery parts, the degree of corroded on the surface is higher, the composition of the rusty oxides are more complicated, and the binding force between the matrix and the oxide layer is greater." - This sentence needs to explain in what way, and why, are these statements true.
Line 69: "there are relatively little researches on such pollutants." - Which pollutants? More context needed.
Line 71: "excessive energy may cause damage to the matrix and affect some key performance of parts" - What is intended by "matrix", and what kind of damage is caused?
Line 80: the "laser torch" needs to be described in detail, since it is responsible for shaping the energy profile of the beam.
Line 82: "The laser is a solid-state laser with a flat-topped laser energy" - The author must provide the energy profile of the laser beam. These profiles are never perfectly flat.
Lines 91, 92, 102 and others: "dirt" is not a scientific term.
KHZ is not a unit of measure for frequency. The correct unit is kHz. There are many instances of this mistake.
Line 92 mentions X-ray diffraction analysis, but the article does not seem to contain any data from such measurements.
Experimental and Analytical Methods section: the authors do not mention the exact pulse duration, although it is known that this parameter is crucial for the phenomena occurring during material ablation. In fact, the paper as whole does not take pulse duration into account in any way. This is a critical failure of their work.
Line 126 - the symbol for platinum is Pt.
Line 311 - "A 3.5% sodium chloride solution was prepared to simulate the environment in which corrosion occurred" - why was sodium chloride chosen for environmental simulation? The paper is specifically targeting mining, so a salt mine seems to be the only place where such large concentrations of NaCl would be present.
Line 316 - What is "degree of difficulty of corrosion"?
Line 317 - What is intended by "liveness of the sample"? Note that "liveness" is not even an English word!
Line 364 - What does it mean "the removal effect is relatively the best"? Relative to what?
Author Response
Dear reviewers:
Thank you for commenting on our manuscript entitled “Investigation of the Surface Integrity of Q345 Steel After Nd:YAG Laser Cleaning of Oxidized Mining Parts” (Manuscript ID: coatings-856299).
We have studied the comments carefully and have made corrections which we hope meet with approval. All the changes are marked in red in the revised manuscript.The answers to your comments are listed in the attachment.
Sincerely
Liming Wang
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have improved considerably the paper following my commnets. The paper can be published in the current format.
Author Response
Dear reviewer:
Thank you for commenting on our manuscript entitled “Investigation of the Surface Integrity of Q345 Steel After Nd:YAG Laser Cleaning of Oxidized Mining Parts” (Manuscript ID: coatings-856299).
We are very appreciated the reviewer's comments and suggestions. From the revision process, the quality of the article has been significantly improved. Thank you very much.
Sincerely
Liming Wang
[email protected]
Author Response File: 
Author Response.docx
Reviewer 2 Report
The quality in style and grammar has increased in the present version of the manuscript, and the relevance has likewise improved, but the paper is still unacceptable for publication, unless some changes are made:
"to remove oxides for reuse." This sentence needs a rewrite. The reader should not have to guess what the authors intention was.
"The composition of mining mechanical deposits is complex" Again, entirely unclear. I guess some words need to be moved around somehow, but as is, the sentence is nonsensical.
"due to its bad working environment." The word "bad" is not a relevant scientific category. Please do elaborate in what way is the environment "bad".
A similar comment relates to "the microstructure of the sample surface enhanced". You must qualify what it is meant by "enhanced".
"excessive energy is capable of easily destroying surface integrity, such as the surface roughness (Ra), microstructure, element content, microhardness (HV), and corrosion resistance." This sentence says that surface roughness correlates to surface integrity - more rougness equals to more integrity. Please rewrite the sentence to make it sensible.
"A force of 300-g was applied during the measurement of the hardness tester" Please specify the type of hardness test executed. Was this a Vickers hardness test? If so, why don't the authors write/state as much? This is actually the same issue I had with the first version of the manuscript, and it baffles me that I have to ask the authors to explicitly state the actual hardness measurement method, after I have already explained that the method of measurement is crucial. I would urge the authors to also explain why did they use a Vickers hardness test (which is what I am guessing happened, but of course I cannot be entirely sure).
"when the repetition rate was too high, the cleaning effect was
bad, which proved the existence of an impact effect of the pulse on the materials surface during the laser cleaning process" - Again, what is the meaning of "bad", in scientific or technical terms? Additionally, it is unclear what this entire sentence means, since this "impact effect" is also unclear. This has to be explained clearly, as it seems to be a crucial part of the manuscript.
In some places the word "bad" can be easily replaced with "poor", such as in "and the corrosion resistance was bad.", but in the examples above, the sentences need to be rewritten.
"the hardness layer produced by the surface layer under the action of compressive stress was denser" - What exactly is this "hardness layer"?
Author Response
Dear reviewer:
Thank you for commenting on our manuscript entitled “Investigation of the Surface Integrity of Q345 Steel After Nd:YAG Laser Cleaning of Oxidized Mining Parts” (Manuscript ID: coatings-856299).
We are very appreciated the reviewer's comments and suggestions. We have studied the comments carefully and have made corrections which we hope meet with approval. All the changes are marked in red in the revised manuscript.The answers to your comments are listed in the attachment.
Sincerely
Liming Wang
[email protected]
Author Response File: Author Response.docx
