Hot Deformation Constitutive Equation and Plastic Instability of 30Cr4MoNiV Ultra-High-Strength Steel

Round 1

Reviewer 1 Report

In the presented work, the hot deformation behavior of 30Cr4MoNiV UHS steel was studied by isothermal compression tests. The research was carried out using the Gleeble-3500 thermal simulation machine. Interesting dependencies were obtained for this ultra-high-strength steel. It can be said that the study was well done in a classic style without much comment.The paper could be accept in present form.

Author Response

Dear reviewer,
Thank you for your earnest comments and advice on Hot deformation constitutive equation and plastic instability of 30Cr4MoNiV ultra-high-strength steel (Metals-1194672). Those comments are all valuable and very helpful for revising and improving our paper, as well as important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. The revisions are marked in red in the manuscript. The replies for the reviewer and the editor are as follows.

Author Response File: Author Response.pdf

Reviewer 2 Report

The topic of the work is very interesting and in my opinion the manuscript on deformation of ultra-high-strength steel should be published. The article is supported by numerous studies, and their results are presented in clear charts and diagrams. My comments are below:
1. Abstract is very legible and clearly presents the content of the work
2. The summary is correct. The authors cite other works in a thoughtful manner. There are no unnecessary collective citations, which deserves a good word.
3. Authors should read the journal's requirements for entering equipment manufacturers in parentheses
4. Does the chemical composition of the steel come from an attestation or was it tested in a laboratory? There is no such information. The exact chemical composition is given, not the ranges of individual elements. Hence my question.
5. The results are supported by conclusions 

Author Response

Dear reviewer,
Thank you for your earnest comments and advice on Hot deformation constitutive equation and plastic instability of 30Cr4MoNiV ultra-high-strength steel (Metals-1194672). Those comments are all valuable and very helpful for revising and improving our paper, as well as important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. The revisions are marked in red in the manuscript. The replies for the reviewer and the editor are as follows.

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors in a well described manuscript consider the analysis of plastic instability in a specific UHS steel. This type of approaches has been extensively published considering different type of materials, as the authors indicate in the Introduction section. Nevertheless, the work is nicely presented with a good description of the methodology included in the work. The discussion/conclusions are also well defined. Based on this, this referee considers that this manuscript is acceptable with some minor revisions, detailed as follows:

• In table 1, it is recommended to define the chemical composition with only 2 decimals (no 4).
• The reheating cycle considers only 3 min holding time (line 110). Taking into account that this short time will have very small effect in the dissolution on previous carbides, it should be convenient to include the microstructural characteristics of the as-received material or just after quenching before deformation application. 
• There is a mistake in the text of Fig. 8: the symbol corresponds to strain rate, but it is strain (ε=0.3, for example) 

Author Response

Dear reviewer,
Thank you for your earnest comments and advice on Hot deformation constitutive equation and plastic instability of 30Cr4MoNiV ultra-high-strength steel (Metals-1194672). Those comments are all valuable and very helpful for revising and improving our paper, as well as important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. The revisions are marked in red in the manuscript. The replies for the reviewer and the editor are as follows.

Author Response File: Author Response.pdf

Reviewer 4 Report

This is an interesting work which could by published in Metals. The study of the hot deformation behavior of 30Cr4MoNiV steel is a fundamental topic for multiple technological applications. The study has been carried out the state of the art methods. Conclusions are sound. However, I do have several minor suggestions aimed to improve the paper.

1. Minimize the abbreviation and technical nomenclature used in the abstract. The abstract should be as much plain as possible to attract readers.
2. In the introduction after “The plastic deformation under the combined action of heat and force can undoubtedly have a significant impact on the structure of the material and ultimately determine its service performance.” It should be stated that “Plastic deformation is extremely sensitive to external factor like temperature and pressure” citing relevant works; for instance: S. Anzellini et al. Crystals 2021, 11(4), 452; Errandonea, D. et al. Phys. B Condens. Matter 2005, 355, 116–125; and S G MacLeod et al. 2021 J. Phys.: Condens. Matter 33, 154001. After that continue with “The plastic deformation under the combined …”.
3. Many parameters; for instance, power dissipation and instability parameter, are not defined. Please define them or give references. Not everybody is familiar with them.
4. Provide the accuracy of temperature measurements. +/- 1ºC?
5. How was the chemical composition determined? By chemical analysis? Or it is given by the vendor of the material?
6. Can peak stresses given in Table 2 determined with two decimal digits?
7. The two parameters given in the argument of the exponential function if equation 9 are correlated and can be replaced by only one parameter.
8. Does it make sense to make a seventh order polynomial fit to the results of Fig. 5? Probably a lower order polynomial is enough. The seventh order can lead to mathematical artifacts.
9. In Fig. 7, R should be R squared.
10. Equation should be removed from conclusions.

Author Response

Dear reviewer,
Thank you for your earnest comments and advice on Hot deformation constitutive equation and plastic instability of 30Cr4MoNiV ultra-high-strength steel (Metals-1194672). Those comments are all valuable and very helpful for revising and improving our paper, as well as important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. The revisions are marked in red in the manuscript. The replies for the reviewer and the editor are as follows.

Author Response File: Author Response.pdf