New Equipment and Method for Refining the Solidified Grain Structure

Round 1

Reviewer 1 Report

Dear authors,

Congratulations for this paper, your methodology seems to be very promising and that should have required a lot of work.

I have a number of remarks, that could be listed as weaknesses of the paper :

1) you clearly proved the refining effect of your original method but it is in a metallurgical system where refining is already possible by traditional methodologies

2) you did not prove the absence of macrosegregation by specific measurements, even though it is expected due to the symmetries of the flow you are forcing into the melt

3) the labels in the figures (a,b,c,...) are explained in the text and not in the legends, so the author has to browse the text to find the details

Best regards

Author Response

Dear Reviewer,

 

Thank you very much for your kind help regarding the handling of our manuscript for publication in Metals. Here we give an answer to all your questions and comments.

 

Yours sincerely,

 

András Roósz, corresponding author

 

 

Review's #1

 

 

Dear authors,

Congratulations for this paper, your methodology seems to be very promising and that should have required a lot of work.

I have a number of remarks, that could be listed as weaknesses of the paper :

1) you clearly proved the refining effect of your original method but it is in a metallurgical system where refining is already possible by traditional methodologies

 

No effective grain refinement materials are known in the case of the steels and Cu-based alloys. It is especially very difficult to find such a material in the case of steels due to their very high melt temperatures. Some materials that would be suitable as far as their melting point is concerned can, however, significantly worsen the mechanical properties. Also, there is some product from aluminium in which the grain refinement materials are harmful (i.e., the press ingot).

 

2) you did not prove the absence of macrosegregation by specific measurements, even though it is expected due to the symmetries of the flow you are forcing into the melt

 

In 4.3.2. we show it.

 

3) the labels in the figures (a,b,c,...) are explained in the text and not in the legends, so the author has to browse the text to find the details

 

In the revised manuscript, we have shown the applicability by some detailed experiments.

 

 

Reviewer 2 Report

1) The paper is not well orgnized as a researh paper, which look like a patent  application. 

2) It has been well know that the stirring by EMS can break down the crystal dendrite and refine the solidificaiton structure. EMS by  travelling  magnetic field discussed in the paper is also not a new method or instrumentation.    

Author Response

Dear Reviewer,

 

Thank you very much for your kind help regarding the handling of our manuscript for publication in Metals. Here we give an answer to all your questions and comments.

 

Yours sincerely,

 

András Roósz, corresponding author

 

 

Review's #2

1) The paper is not well orgnized as a researh paper, which look like a patent  application. 

 

This paper shows a new type of TMF inductor patented, but similar can not be found in the literature. And in the new version, we have shown the applicability by some detailed experiments.

 

2) It has been well know that the stirring by EMS can break down the crystal dendrite and refine the solidificaiton structure. EMS by  travelling  magnetic field discussed in the paper is also not a new method or instrumentation.    

Indeed, the break of the dendrite arms by the strong melt flow and the effect of the stirring by traveling magnetic field is known. But, with our equipment, we can produce the most significant shearing stress to develop where the flow is perpendicular to the solidification front by causing part of the metallic melt layers touching each other to flow in an opposite direction. In the literature, we did not find similar equipment and method.

 

 

Reviewer 3 Report

the present manuscript presents a novel method for the grain refinement by using a magnetic inductor developed by the authors to induce a stirring flow inside the molten metal during the solidifcation. the topic is interesting and the solution proposed by the authors is captivating. the equipment and the operating principle are thorouglhy described, which is very good point. However, the paper is weak from a scientific point of view: a very few test cases are reported and the presented results are poor and not conclusive. Based on what has been reported in the manuscirpt, the validity of the proposed solution is questionable. Significant improvements are needed i terms of experiments to be conducted, data (especially quantitative) and results to be reported in the manuscript, adn their critical discussion. other comments are reported in the pdf file

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

 

Thank you very much for your kind help regarding the handling of our manuscript for publication in Metals. Here we give an answer to all your questions and comments.

 

Yours sincerely,

 

András Roósz, corresponding author

 

 

Review's #3

he present manuscript presents a novel method for the grain refinement by using a magnetic inductor developed by the authors to induce a stirring flow inside the molten metal during the solidifcation. the topic is interesting and the solution proposed by the authors is captivating. the equipment and the operating principle are thorouglhy described, which is very good point. However, the paper is weak from a scientific point of view: a very few test cases are reported and the presented results are poor and not conclusive. Based on what has been reported in the manuscirpt, the validity of the proposed solution is questionable. Significant improvements are needed i terms of experiments to be conducted, data (especially quantitative) and results to be reported in the manuscript, adn their critical discussion. other comments are reported in the pdf file

In the revised manuscript, we have shown the applicability by some detailed experiments.

 

Reviewer 4 Report

1. The second part of the article describes various methods of grain refinement and raises corresponding questions. I don't think this part needs to be described in too much detail, it can be refined and integrated with the introduction.
2. For the grain size analysis in Figure 14, where were these images taken within the samples? Side or heart? And few grains are present in the images, I am skeptical that these single images are truly representative of the entire sample.
3. How were the magnetic induction selected for this paper? If it was based off of another paper, were other experimental parameters consistent with the other papers?
4. It is mentioned in this paper that compared with no magnetic stirring, the crystal grains have been refined after adopting this method. But compared with other magnetic stirring methods, whether the grains of this method are finer.
5. Please check and correct the grammatical errors in the text.

Author Response

Dear Reviewer,

 

Thank you very much for your kind help regarding the handling of our manuscript for publication in Metals. Here we give an answer to all your questions and comments.

 

Yours sincerely,

 

András Roósz, corresponding author

 

 

Review's #4

 

1. The second part of the article describes various methods of grain refinement and raises corresponding questions. I don't think this part needs to be described in too much detail, it can be refined and integrated with the introduction.

 

We think it is necessary to review the fundamentals of the different grain refinement methods because we would like to show the benefits of our method (like no grain refinement material, no any oxide in the workpiece the macrosegregation can be eliminated).

 

1. For the grain size analysis in Figure 14, where were these images taken within the samples? Side or heart? And few grains are present in the images, I am skeptical that these single images are truly representative of the entire sample.

 

The microstructure of the samples in the original version (Fig. 14.) characterizes the whole sample. In the revised version of the manuscript, we changed the experiments. In Figs. 17. and 18. we show the microstructure (dendritic and grain structures) of the samples that characterize the whole sample.

 

1. How were the magnetic induction selected for this paper? If it was based off of another paper, were other experimental parameters consistent with the other papers?

 

As we mentioned in point 2, we changed the shown experiments. During our CETSOL  HUNGARY (Columnar-to-Equiaxed Transition in SOLidification Processing) project, we prepared many more experiments with the new type of TMF facility. From these experiments, we selected some representatives to show the facility's ability. These results are original, and we did not publish those in another paper. These are only in the report of the project.

 

1. It is mentioned in this paper that compared with no magnetic stirring, the crystal grains have been refined after adopting this method. But compared with other magnetic stirring methods, whether the grains of this method are finer.

 

In the literature can be found many experiments in which the authors investigated the effect of magnetic stirring on the grain and dendritic structure, indeed. But, it is not too easy to compare with the results of the other type of experiments because we did not find any systematic experiments where the alloy (Al – 7% Si), the sample geometry, and the magnetic induction was the same or similar. In some papers, magnetic induction is characterized by the current density only. The collection and the analysis of the results of the other type of stirring will be the task of another paper, if it is possible at all.

 

1. Please check and correct the grammatical errors in the text.

 

The MDPI English Edited Office checked the English grammar.