Study of the Effect of Carbon on the Contraction of Hypo-Peritectic Steels during Initial Solidification by Surface Roughness
Round 1
Reviewer 1 Report
I Believe that the article could be accepted after some major changes to the article.
General comments:
The article is in need of major language check. There are missing words to form complete sentences and several grammar isues.
In depth suggestions
The different materials can be seen in Table 1, can you verify that the additional elements in the different steel grades won't affect the effects that you are studying?
I would increase the size of Figure 1
On line 125, 140-141 and 151 you have mentioned the temperatures where the phase transformations have occured. Is it possble to draw any conclusions from those temperatures?
On line 128 you have stated Figure 4d, it is 2d isn't it?
An expression on Line 128-129, but also mentioned at other places puzzles me. It is mentioned that the wrinkles has "directionality in a small range", what do you mean by that? Explain! You have to be more careful when explaining the difference between the wrinkles from the upper and lower transformations. It is not easy to see these differences in you images if you do not know what you are looking for.
Line 158 and 3.2 Measurement of Surface roughness
I would put the information regarding your measurements with confocal microscopy measurements in the material and method section. Only results and discussions in this section.
Why is there a difference between the a and b directions when you are measuring? This is linked to your poor explanation of the difference between the wrinkles at high and low temperatures. It would be easier to understand if you explained it more.
Figure 8 shows how the surface roughness is changes as a function of carbon content. How do you correlate the resulting surface roughness to a realistic shrinkage? Which relationships exists? Since you were interested in showing how efficient this method is to simulations, it should be possible to correlate them to an actual shrinkage in per cent.
Author Response
In depth suggestions
1.The different materials can be seen in Table 1, can you verify that the additional elements in the different steel grades won't affect the effects that you are studying?
Re:The additional elements in the different steel grades will affect shrinkage degree of peritectic phase transition.But in this paper, the content of alloying elements is very close,and the relative position of each type of steel remains unchanged in iron-carbon phase diagram accoding to the equivalent carbon content.Therefore,the different alloy contents will not effects the study results.
2.I would increase the size of Figure 1
Re:The size of Figure 1 have been increased.
3.On line 125, 140-141 and 151 you have mentioned the temperatures where the phase transformations have occured. Is it possble to draw any conclusions from those temperatures?
Re:One of the target of the paper is to measure the surface roughness caused by peritectic phase transition directly.Therefore,the temperatures range where the phase transformations occurred is the key factor to estimate the influence of transformations to surface roughness and conclude that the different phase transitions have different effects on the surface roughness.
4.On line 128 you have stated Figure 4d, it is 2d isn't it?
Re:Yes,it is.
5.An expression on Line 128-129, but also mentioned at other places puzzles me. It is mentioned that the wrinkles has "directionality in a small range", what do you mean by that? Explain! You 6.have to be more careful when explaining the difference between the wrinkles from the upper and lower transformations. It is not easy to see these differences in you images if you do not know what you are looking for.
Re:This paper indicated that the surface roughness is mainly influenced by δ→γ transformation and the γ→α, γ→α + Fe3C transformation. However, JiangLiu et al [22] mention of low temperature wrinkling represent the transformation of austenite to proeutectoid ferrite. Because under a cooling rate of 1°C/s ,the the proeutectoid ferrite first grows in the original austenite grain boundary nucleation and grows along the grain boundary.So,the direction of low temperature phase transformation surface roughness is dependented by the grow orientation of proeutectoid ferrite. Therefore,the "directionality in a small range" represent the grow orientation of proeutectoid ferrite.
7.Line 158 and 3.2 Measurement of Surface roughness
I would put the information regarding your measurements with confocal microscopy measurements in the material and method section. Only results and discussions in this section.
Re:The 3.2 Measurement of Surface roughness have been adjust to material and method section.
8.Why is there a difference between the a and b directions when you are measuring? This is linked to your poor explanation of the difference between the wrinkles at high and low temperatures. It would be easier to understand if you explained it more.
Re:This paper indicated that the surface roughness is mainly influenced by δ→γ transformation and the γ→α, γ→α + Fe3C transformation. The roughness which caused by δ→γ transformation has no difference in any direction. But the low temperatures surface roughness is dependented by the grow of proeutectoid ferrite.Therefore the "directionality in a small range" represent the grow orientation of proeutectoid ferrite. Making the measure line perpendicular to the direction of the surface wrinkles (a-method),the value of surface roughness would combine the influence of high and low temperatures transformation. However,when the surface roughness measurement line along to the direction of the low temperatures surface roughness wrinkles,the influence of low-temperature phase transformation on surface roughness can be avoid, the value of surface roughness Ra(δ/γ) can measured directly.
9.Figure 8 shows how the surface roughness is changes as a function of carbon content. How do you correlate the resulting surface roughness to a realistic shrinkage? Which relationships exists? Since you were interested in showing how efficient this method is to simulations, it should be possible to correlate them to an actual shrinkage in per cent.
Re:Abe et al. [31] consider that the surface roughness of metal is positively proportional to the strain and proposed a calculate formulas to describe the relationships between surface roughness and strain.
Rmax=Cmax xdy
Rmax :the maximum surface roughness; Cmax: the non-dimensional constant ;x: plastic strain
dy: the grain size in the vertical direction.
The author tries to establish such a relationship in the study,but the non-dimensional constant still need takes a lot of work to get it.Therefore,the authors have to temporarily refer to the calculation results of Jablonka D M A[11] under similar undercooling conditions. Figure 8a shows the surface roughness is changes as a function of carbon content, Figure 8b shows the relationships bewteen shrinkage and carbon content.The carbon content dependence of the calculated thermal contraction is in good agreement with the measured value of surface roughness Ra (δ/γ).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In the previous work “Materials, 11(4), 571.” The authors have done similar research on low to high carbon steel for Evaluating the Contraction of Hypo-Peritectic Steels during Initial Solidification by Surface Roughness. The two papers have complete similarity in the experimental and characterization methods. The authors should give a detail illustration about this and highlight the present manuscript. They should address what is new they have done in their research. This is the main concern in this manuscript.
All the references are very much old, and this topic has been studied extensively by the other researcher which is not provided in the literature review/introduction section.
The major conclusions lack scientific explanation. There exist grammatical, syntax or word usage errors in the manuscript. The above-written issues could prevent the paper from being published.
Author Response
Comments and Suggestions for Authors
1.In the previous work “Materials, 11(4), 571.” The authors have done similar research on how to high carbon steel for Evaluating the Contraction of Hypo-Peritectic Steels during Initial Solidification by Surface Roughness. The two papers have complete similarity in the experimental and characterization methods. The authors should give a detail illustration about this and highlight the present manuscript. They should address what is new they have done in their research. This is the main concern in this manuscript.
Re:Compared to “Materials, 11(4), 571”this paper used new method measured surface roughness Ra (δ/γ) directly. The experimental steel samples of previous paper is hypo-peritectic steel and several non-peritectic steel. The surface roughness Ra (δ/γ) of hypo-peritectic is simply calculated by formula(1):
R a ( δ → γ ) = R a -（R a ( γ → α ) + R a ( γ → α + Fe 3 C) ) (1)
However, the above methods are not accurate enough because the low temperatures transformation surface roughness of different steel may different. This paper avoid the low temperatures transformation surface roughness, measured surface roughness Ra (δ/γ) directly.
The “Materials, 11(4), 571”have been focused on the innovation of evaluating method, while this paper use the new evaluate method study the effect of carbon on the Contraction. Not only verifies the reliability of the evaluate method, but also improves the measurement precision of the roughness Ra (δ/γ).
2.All the references are very much old, and this topic has been studied extensively by the other researcher which is not provided in the literature review/introduction section.
Re:The author have revision the literature review section,and provided recent development of studies in related fields.
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3.The major conclusions lack scientific explanation. There exist grammatical, syntax or word usage errors in the manuscript. The above-written issues could prevent the paper from being published.
Re:The author revise conclusions section and try to make more scientific explan. For exist grammatical, syntax or word usage errors in the manuscript, the author already Seek help from MDPI English editing.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The outline and main content for this manuscript are good. The authors gave an additional explanation and highlighted the present manuscript. I enjoyed reading the work and believe that the authors have promising results that are worthy of publication. Authors have mentioned that they have already sought help for English check.