Recrystallization Mechanism and Processing Map of 18CrNiMo7-6 Alloy Steel during Hot Deformation

Round 1

Reviewer 1 Report

The obtaining of the constitutive equations and determining the optimal deformation conditions are necessary for the development of deformation technologies for the steel. The authors of the paper "Recrystallization Mechanism and Processing Map of 18CrNiMo7-6 Alloy Steel during Hot Deformation" present an experimental investigation of the hot deformation behavior of NiCrMo steel. The authors determine the stable and unstable deformation range using the processing maps. However, the presented results should be significantly improved accordingly to the following comments:

1. The main problem of the paper is that the authors did not consider the influence of friction and adiabatic heating during the deformation. The friction between the sample’s edges and the dies such as adiabatic heating during the deformation may significantly influence the true stress – true strain curves [10.1016/j.jallcom.2018.08.010, 10.1134/S0031918X14080031, 10.1179/026708301101510843]. The stress-strain curves are presented in Figure 2. There are no microstructural reasons for increases in the stress after about 0.4. The increase is due to friction. As a result, all coefficients in the constitutive model and constructed processing maps are incorrect. The authors should recalculate the stress-strain curves considering friction and adiabatic heating and reconstruct the constitutive model and processing maps.
2. The arrowed in Figure 5d objects seem to not be "cracks just grain boundaries. It is recommended to provide a more quality image or remove this figure.
3. Minor correction:

- The number of digits in the model’s coefficients should be decreased accordingly to the statistical error of their determination.

Author Response

Please see the attachment

Dear Editors and Experts

      

       We had received referees reports from three experts. And the experts had left us many fantastic suggestions. We revised the manuscript on the advice of the experts. The following is the specific content of our revision.

 

Suggestions 1:

The main problem of the paper is that the authors did not consider the influence of friction and adiabatic heating during the deformation. The friction between the sample’s edges and the dies such as adiabatic heating during the deformation may significantly influence the true stress – true strain curves. The stress-strain curves are presented in Figure 2. There are no microstructural reasons for increases in the stress after about 0.4. The increase is due to friction. As a result, all coefficients in the constitutive model and constructed processing maps are incorrect. The authors should recalculate the stress-strain curves considering friction and adiabatic heating and reconstruct the constitutive model and processing maps.

Response：

(1) Adiabatic and friction coefficient correction were introduced before the flow stress curve was drawn. Section 3.1 (Correction of friction and temperature) was added to describe the principles of adiabatic and friction coefficient correction.

(2) We revised the flow stress curve in Section 3.2 and added the friction and temperature correction flow curves in Fig.2.

(3) In Section 3.3, we recalculated various parameters in the constitutive equation and established the constitutive equation again 

(4) Since the value of flow stress changed after correction, the processing maps we drew earlier are incorrect t, we recalculated and drew new processing maps. 

 

Suggestions 2：

The arrowed in Figure 5d objects seem to not be "cracks just grain boundaries. It is recommended to provide a more quality image or remove this figure.

Response：

       We had removed Fig.5d.

 

Suggestions 3:

The number of digits in the model’s coefficients should be decreased accordingly to the statistical error of their determination.

Response：

       The number of model coefficients is unified as 2 significant digits.

 

Suggestions 4:

       The "Introduction" section ends with a statement of what has been done in the work. I recommend expanding the "Introduction" section and completing it with the formulation of the goal and the rationale for scientific novelty.

Response：

       A description of the necessity of research and a brief description of the results obtained in this paper have been added.

 

Suggestions 5:

Figures 1,3,4,5,7,9 are presented in low quality. You need to increase the resolution of photos and drawings.

Response：

       The previous pictures were generated by screenshots, so they presented in low quality, we had exported the pictures between drawing software in a way that be higher definition pictures.

 

Suggestions 6:

       The article is not framed in a template, there is no line numbering. This complicates the peer review process. It is difficult to point out errors and shortcomings in the text.

Response：

       We reformatted the manuscript and added line numbers.

 

Suggestions 7:

The article twice mentions a Figure 4. The first Figure 4 is framed unsuccessfully. It is difficult to understand and see what is written on the axes. The drawing looks ugly.

Response：

       The first Fig.4 was merged into Fig.3 and the 3D graphic was removed. In addition, a line chart was used to describe the peak stress.

 

Suggestions 8:

       In the article, in some places the temperature is indicated as 1050 °C, and in some places, for example, Fig. 2 as 1,050 ° Need to fix to 1050 °С.

Response：

       The above problems have been corrected and other similar problems that may appear in the manuscript have been checked. In addition, the unit symbol display may be incorrect due to encoding, which we have converted to UTF-8.

 

Suggestions 9:

On the dimensional scale (Fig.7 and 8) indistinguishable numbers. You need to increase the numbers on the scale.

Response：

We increased the number on the scale in Fig.8. And in the table of misorientation angles shown in Fig.7, three colored lines represent grain boundaries at different angles.

 

Suggestions 10:

«The alloy was thin plate specimen with size of 8mm × 5mm × 3mm». What machining was used to make these specimens?

Response：

“Thin plate specimen of alloy 8mm × 5mm × 3mm, processed by molybdenum wire cutting machine.” In the actual processing process, the thickness of the cutting gap and the electrolytic loss of grinding need to be taken into account, and there is a slight deviation in the actual specimen size. 

 

Suggestions 11:

In Fig. 9(a),  mark to "twining" . However, P9, No discuss or explain. 

Response：

       An explanation of “twining” is increased in line 258,

reference is “Nucleation and microtexture development under dynamic recrystallization of copper”[doi:10.1016/s0921-5093(01)01336-3].

 

Suggestions 12:

       Both Abstract and Conclusions part, should be clearing, hard to p Important information.

Response：

       The part of the abstract is revised to make the content of the abstract more consistent with the full article.

 

I am very grateful to the experts for their advice and have made corresponding modifications. And I sincerely look forward to receiving advice and reply again.

 

Kind regards,

Yikui Xie

Shanghai Unversity

 

Reviewer 2 Report

The article is devoted to a topical issue, namely, the study of the conditions of hot deformation and recrystallization of the 18CrNiMo7-6 alloy. The article has all the signs of competent scientific work and will be of interest to readers. However, now there are shortcomings in the work that worsen the overall impression of it.

1. The "Introduction" section ends with a statement of what has been done in the work. I recommend expanding the "Introduction" section and completing it with the formulation of the goal and the rationale for scientific novelty.
2. Figures 1,3,4,5,7,9 are presented in low quality. You need to increase the resolution of photos and drawings.
3. The article is not framed in a template, there is no line numbering. This complicates the peer review process. It is difficult to point out errors and shortcomings in the text.
4. The article twice mentions a Figure 4. The first Figure 4 is framed unsuccessfully. It is difficult to understand and see what is written on the axes. The drawing looks ugly.
5. In the article, in some places the temperature is indicated as 1050 °C, and in some places, for example, Fig. 2 as 1,050 ° Need to fix to 1050 °С.
6. On the dimensional scale (Fig.7 and 8) indistinguishable numbers. You need to increase the numbers on the scale.
7. «The alloy was thin plate specimen with size of 8mm × 5mm × 3mm». What machining was used to make these specimens?

Author Response

Please see the attachment

Dear Editors and Experts  

       We had received referees reports from three experts. And the experts had left us many fantastic suggestions. We revised the manuscript on the advice of the experts. The following is the specific content of our revision.

 

Suggestions 1:

The main problem of the paper is that the authors did not consider the influence of friction and adiabatic heating during the deformation. The friction between the sample’s edges and the dies such as adiabatic heating during the deformation may significantly influence the true stress – true strain curves. The stress-strain curves are presented in Figure 2. There are no microstructural reasons for increases in the stress after about 0.4. The increase is due to friction. As a result, all coefficients in the constitutive model and constructed processing maps are incorrect. The authors should recalculate the stress-strain curves considering friction and adiabatic heating and reconstruct the constitutive model and processing maps.

Response：

(1) Adiabatic and friction coefficient correction were introduced before the flow stress curve was drawn. Section 3.1 (Correction of friction and temperature) was added to describe the principles of adiabatic and friction coefficient correction.

(2) We revised the flow stress curve in Section 3.2 and added the friction and temperature correction flow curves in Fig.2.

(3) In Section 3.3, we recalculated various parameters in the constitutive equation and established the constitutive equation again 

(4) Since the value of flow stress changed after correction, the processing maps we drew earlier are incorrect t, we recalculated and drew new processing maps. 

 

Suggestions 2：

The arrowed in Figure 5d objects seem to not be "cracks just grain boundaries. It is recommended to provide a more quality image or remove this figure.

Response：

       We had removed Fig.5d.

 

Suggestions 3:

The number of digits in the model’s coefficients should be decreased accordingly to the statistical error of their determination.

Response：

       The number of model coefficients is unified as 2 significant digits.

 

Suggestions 4:

       The "Introduction" section ends with a statement of what has been done in the work. I recommend expanding the "Introduction" section and completing it with the formulation of the goal and the rationale for scientific novelty.

Response：

       A description of the necessity of research and a brief description of the results obtained in this paper have been added.

 

Suggestions 5:

Figures 1,3,4,5,7,9 are presented in low quality. You need to increase the resolution of photos and drawings.

Response：

       The previous pictures were generated by screenshots, so they presented in low quality, we had exported the pictures between drawing software in a way that be higher definition pictures.

 

Suggestions 6:

       The article is not framed in a template, there is no line numbering. This complicates the peer review process. It is difficult to point out errors and shortcomings in the text.

Response：

       We reformatted the manuscript and added line numbers.

 

Suggestions 7:

The article twice mentions a Figure 4. The first Figure 4 is framed unsuccessfully. It is difficult to understand and see what is written on the axes. The drawing looks ugly.

Response：

       The first Fig.4 was merged into Fig.3 and the 3D graphic was removed. In addition, a line chart was used to describe the peak stress.

 

Suggestions 8:

       In the article, in some places the temperature is indicated as 1050 °C, and in some places, for example, Fig. 2 as 1,050 ° Need to fix to 1050 °С.

Response：

       The above problems have been corrected and other similar problems that may appear in the manuscript have been checked. In addition, the unit symbol display may be incorrect due to encoding, which we have converted to UTF-8.

 

Suggestions 9:

On the dimensional scale (Fig.7 and 8) indistinguishable numbers. You need to increase the numbers on the scale.

Response：

We increased the number on the scale in Fig.8. And in the table of misorientation angles shown in Fig.7, three colored lines represent grain boundaries at different angles.

 

Suggestions 10:

«The alloy was thin plate specimen with size of 8mm × 5mm × 3mm». What machining was used to make these specimens?

Response：

“Thin plate specimen of alloy 8mm × 5mm × 3mm, processed by molybdenum wire cutting machine.” In the actual processing process, the thickness of the cutting gap and the electrolytic loss of grinding need to be taken into account, and there is a slight deviation in the actual specimen size. 

 

Suggestions 11:

In Fig. 9(a),  mark to "twining" . However, P9, No discuss or explain. 

Response：

       An explanation of “twining” is increased in line 258,

reference is “Nucleation and microtexture development under dynamic recrystallization of copper”[doi:10.1016/s0921-5093(01)01336-3].

 

Suggestions 12:

       Both Abstract and Conclusions part, should be clearing, hard to p Important information.

Response：

       The part of the abstract is revised to make the content of the abstract more consistent with the full article.

 

I am very grateful to the experts for their advice and have made corresponding modifications. And I sincerely look forward to receiving advice and reply again.

 

Kind regards,

Yikui Xie

Shanghai Unversity

Reviewer 3 Report

1） In Fig. 9(a),  mark to "twining" . However, P9, No discuss or explain. 

2) Both  Abstract and  Conclusions part, should be clearing, hard to p Important information.

Author Response

Please see the attachment

Dear Editors and Experts

       We had received referees reports from three experts. And the experts had left us many fantastic suggestions. We revised the manuscript on the advice of the experts. The following is the specific content of our revision.

 

Suggestions 1:

The main problem of the paper is that the authors did not consider the influence of friction and adiabatic heating during the deformation. The friction between the sample’s edges and the dies such as adiabatic heating during the deformation may significantly influence the true stress – true strain curves. The stress-strain curves are presented in Figure 2. There are no microstructural reasons for increases in the stress after about 0.4. The increase is due to friction. As a result, all coefficients in the constitutive model and constructed processing maps are incorrect. The authors should recalculate the stress-strain curves considering friction and adiabatic heating and reconstruct the constitutive model and processing maps.

Response：

(1) Adiabatic and friction coefficient correction were introduced before the flow stress curve was drawn. Section 3.1 (Correction of friction and temperature) was added to describe the principles of adiabatic and friction coefficient correction.

(2) We revised the flow stress curve in Section 3.2 and added the friction and temperature correction flow curves in Fig.2.

(3) In Section 3.3, we recalculated various parameters in the constitutive equation and established the constitutive equation again 

(4) Since the value of flow stress changed after correction, the processing maps we drew earlier are incorrect t, we recalculated and drew new processing maps. 

 

Suggestions 2：

The arrowed in Figure 5d objects seem to not be "cracks just grain boundaries. It is recommended to provide a more quality image or remove this figure.

Response：

       We had removed Fig.5d.

 

Suggestions 3:

The number of digits in the model’s coefficients should be decreased accordingly to the statistical error of their determination.

Response：

       The number of model coefficients is unified as 2 significant digits.

 

Suggestions 4:

       The "Introduction" section ends with a statement of what has been done in the work. I recommend expanding the "Introduction" section and completing it with the formulation of the goal and the rationale for scientific novelty.

Response：

       A description of the necessity of research and a brief description of the results obtained in this paper have been added.

 

Suggestions 5:

Figures 1,3,4,5,7,9 are presented in low quality. You need to increase the resolution of photos and drawings.

Response：

       The previous pictures were generated by screenshots, so they presented in low quality, we had exported the pictures between drawing software in a way that be higher definition pictures.

 

Suggestions 6:

       The article is not framed in a template, there is no line numbering. This complicates the peer review process. It is difficult to point out errors and shortcomings in the text.

Response：

       We reformatted the manuscript and added line numbers.

 

Suggestions 7:

The article twice mentions a Figure 4. The first Figure 4 is framed unsuccessfully. It is difficult to understand and see what is written on the axes. The drawing looks ugly.

Response：

       The first Fig.4 was merged into Fig.3 and the 3D graphic was removed. In addition, a line chart was used to describe the peak stress.

 

Suggestions 8:

       In the article, in some places the temperature is indicated as 1050 °C, and in some places, for example, Fig. 2 as 1,050 ° Need to fix to 1050 °С.

Response：

       The above problems have been corrected and other similar problems that may appear in the manuscript have been checked. In addition, the unit symbol display may be incorrect due to encoding, which we have converted to UTF-8.

 

Suggestions 9:

On the dimensional scale (Fig.7 and 8) indistinguishable numbers. You need to increase the numbers on the scale.

Response：

We increased the number on the scale in Fig.8. And in the table of misorientation angles shown in Fig.7, three colored lines represent grain boundaries at different angles.

 

Suggestions 10:

«The alloy was thin plate specimen with size of 8mm × 5mm × 3mm». What machining was used to make these specimens?

Response：

“Thin plate specimen of alloy 8mm × 5mm × 3mm, processed by molybdenum wire cutting machine.” In the actual processing process, the thickness of the cutting gap and the electrolytic loss of grinding need to be taken into account, and there is a slight deviation in the actual specimen size. 

 

Suggestions 11:

In Fig. 9(a),  mark to "twining" . However, P9, No discuss or explain. 

Response：

       An explanation of “twining” is increased in line 258,

reference is “Nucleation and microtexture development under dynamic recrystallization of copper”[doi:10.1016/s0921-5093(01)01336-3].

 

Suggestions 12:

       Both Abstract and Conclusions part, should be clearing, hard to p Important information.

Response：

       The part of the abstract is revised to make the content of the abstract more consistent with the full article.

 

I am very grateful to the experts for their advice and have made corresponding modifications. And I sincerely look forward to receiving advice and reply again.

 

Kind regards,

Yikui Xie

Shanghai Unversity

 

Round 2

Reviewer 1 Report

The authors have made necessary changes in the manuscript. The paper may be accepted for publication.