Effect of Lubricating Oil and Wiper on Super-High Strength 7055 Aluminum Alloy Ingots

Round 1

Reviewer 1 Report

Overall remarks. : Good works perform. I would however recommand 3 majors points :

1. referencing to similar work performed 10 years ago, such as "Influence of a wiper on residual stresses in AA7050 rolling plate ingots" from J.M. Drezet and Th. Pirling. (see attached pdf)

2. Precise positionning of the wiper in your process. Please describe the distance between the wipe position and the graphite ring.

3. Phases analysis : The analysis of the phase presented and discussed in figure 6 is missing. Is it Fe-containing particles ? If yes, the discussion about dissolution of it is probably not correct. Fe-phase would probabely not be dissolved during homogeneisation. Or is it not Fe-Phase particles ?

Specific correction

Line 25-26 : Sentance is missing a verb. I would suggest "with low density, high strength, (...) corrosion resistance have bee developped in 1990-2000.

Line 30 : I would suggest to add "hot.cracking" into the liste of defect.

Line 37 : Daily does not seems appropriate here

Line 55 : 501.1°C - The 0.1°C does not look significant here. Were does this value come ? Modelling ? Please consider range of value/error 

Line 62 : Please define what is a wiper and add references to it.

Line 82 : The melting temperature - Are you refering here to the "liquid metal temperature in the melting furnace "?

Lin2 84 : hot-tearind risks (instead of "the")

Line 87 : Is it not avoid instead of "void" ?

Line 88 : Please rework the sentances. Not clear that you are refering to Fe dilution from the tools.

Line 100 : Would sugget to precise type of thermocouples used

Line 114 : Please precise the type of spectrometer and the measurment error expected

Line 122 : Please precise and comment the measurment error of the ALSCAN tester (usually pretty high)

Line 129 : Figure 2 : I would recommand using error bars on the graphs

Line 138 : Please precise that table 2 represent composition analysis AFTER homogeniezation. Note : For the shake of scientific interrest, it would be interresting to compare composition profile as-cast (with and without wiper) and after HO samples.

Line 173 : "was" instead of "did"

Line 178 : I assume you like to say "was" instead of "did not" (The specific case describe here is with the wiper, right ?)

Line 190 : "Heat-up" : Is it really a heating effect or a "slower cooling" effect ?

Line 200 : "have dissolved" : Are you sur that the grain-boundaries phases are only "dissolvable" phase ? I am expecting here also some Fe-Constitiant phase, undissolvable but with some alpha to beta transition. Phase analyisis would be necessary to comment and discussed this.

Line 225/226 : Please rework the last sentances "This advantage can reach homogenizing effect through ingot's heat". Not crystal clear and may be wrongly interpreted depending on phase analysis. I would recommend a more generic "and reduced micro-segregation during casting".

 

Comments for author File: Comments.pdf

Author Response

Please see attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

 

Thank you for submitting your paper. The work done here draws attention to a significant subject chill casting of Al alloys. I have found the paper to be interesting. However, several issues need to be addressed properly before the paper is being considered for publication. My comments including major and minor concerns are given below:

Please consider reviewing the abstract and highlight the novelty, major findings, and conclusions. I suggest reorganizing the abstract, highlighting the novelties introduced. The abstract should contain answers to the following questions:

What problem was studied and why is it important?

What methods were used?

What conclusions can be drawn from the results? (Please provide specific results and not generic ones).

The abstract must be improved. It should be expanded. Please use numbers or % terms to clearly shows us the results in your experimental work.

Please consider reporting on studies related to your work from mdpi journals.

The introduction is too short, and authors need to expand it, mention in details past studies similar to this work, what they did and what were their main findings and critically evaluate their results against each then mention how does your work brings new knowledge and difference to the field.

The authors should remove all bulk citations, unless given full credit afterwards. The authors should check for this issue elsewhere in the manuscript.

Combine any small paragraphs of 5 lines or less with other paragraphs to improve the readability of the manuscript.

In materials and methods section, the authors should add the standard used in the tests carried out in this study.

Authors are encouraged to add images/graphs for the materials in raw form, the fabricated samples for the mechanical tests and equipment/setup used in the study. After all, this is an experimental study, and it is important to add graphical images to clearly show the readers what was done in this work.

How many samples was tested under same conditions? how many variable testing ranges were used?

Change 2. Experimental procedures to 2. Materials and methods.

In the whole manuscript, simply use Al7055 instead of writing 7055 aluminum alloy every time.

Table 1 needs a reference on the caption if not measured by the authors.

Figure 2 add error bars.

Figure 3 the scale bar (ruler) is not clear.

Figure 3 add some arrows and text to clearly show the readers what to look at in the manuscript.

Line 177 does not read well, please check grammar and writing style.

Line 192-193 did the authors measure the stress? Or is this a speculation? In either way the authors need to support this claim with references.

Line 196 change to “the tendency of ingot to crack” or something similar as the current line does not read well.

Figure 6 same comment as for figure 3.

Figure 3 the image on the right side is not clear (it is blurry).

Authors should show the cooling sysetm used in the study in the materials and methods section.

The authors should mention the limitations of their study especially for using thermocouples.

Line 148 “and yield” what yield?

The results are merely described and is limited to comparing the experimental observation and describing results. The authors are encouraged to include a more detailed results and discussion section and critically discuss the observations from this investigation with existing literature.

Conclusion can be expanded or perhaps consider using bullet points (1-2 bullet points) from each of the subsections.

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Manuscript review Study on direct-chill casting super high strength 7055 aluminum alloy ingots by Xiangjie Wang, Yajun Xu, Lingfei Yang, Chengcheng Chen, Zhaoxi Song, Jianzhong Cui.

 

Super high strength 7055 aluminum alloy ingots during direct-chill (DC) casting are investigated in this work.

There are a number of things to note about the work:

1. The title of the article should be changed. To do this, the authors need to decide on the purpose of the work. Because now it does not correspond to a scientific article.

2. There is no reference to the source of literature No. 5 in the text.

3. In the final part of the introduction, the authors indicate that an electromagnetic field was used in the smelting. However, there is no justification for the need for its use in the text of the introduction. I encourage authors to use the overview on this topic: https://0-www-scopus-com.brum.beds.ac.uk/record/display.uri?eid=2-s2.0-85124347081&origin=resultslist&sort=plf-f

4. Line 84 - the authors write about electromagnetic mixing. However, there is no information about the equipment used for this and the characteristics of the field in the text.

5. In fig. 1. It is not indicated how the electromagnetic field was introduced.

6. Two schemes were used in the experiments: without oil-lubrication hot-top casting process and wipers and without. Accordingly, fig. 1 must be supplemented with a diagram of the second processing option. Show how the electromagnetic field is applied, where oil-lubricant, wipers.

7. The composition indicated in Table 1 which ingot refers to?

8. A similar question on the results of chemical analysis after homogenization (Table 2) - why are there no comparative data on an ingot cast under other conditions?

9. Fig. 3 add a length marker to the photo of the structures (remove the black ruler).

10. Line 177-178 Misprint. The authors describe the temperature distribution during melting with wipers, but it is written what happened to them.

11. The results of the study are shown superficially. For example, the authors talk about improving the quality of the surface, but there is no confirmation of these results. When describing differences in microstructure (Section 3.5), the concepts of more/less are used. Obviously, it is necessary to add numerical comparisons of grain sizes, fractions of grain boundary phases, etc.

12. In the discussion, there is no comparison of the results with the literature data, the authors only state the results.

I believe that the work requires serious revision and cannot be recommended for publication.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

There is no word "defection" authors need to replace this word with correct one "defect"

Figure 6 add some arrows and text to clearly show what are we looking at in these microscopic images. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks to the authors for the corrections made to the text of the manuscript. I think that in this form it can be published.

Author Response

We appreciate for Editor and reviewers’ warm work, and thanks for your approval. We will never give up the chance to improve the quality of our manuscript.