Effect of Warm Rolling Temperature on the Microstructure and Texture of Microcarbon Dual-Phase (DP) Steel

Round 1

Reviewer 1 Report

In this paper, the authors study the influence of rolling temperature on the formation of slip strips in AHSS steel. The state of the art and experimental approach are well presented and explained. However, the lack of clarity in the structure of the discussion is regrettable. The conclusion is clearer but it is then difficult to see the logical path between this part and the previous one. Finally, the sentence structures used are difficult to understand. For example, the sentence "Predominant work hardening showed a sharp increase in the dislocation density, the completely breakage of the pearlite group in the hot-rolled microstructure, and the complete elongation of the ferrite grain" (line 199 to 201) is difficult to understand. The captions of the figures are also very short and do not allow the reader to read the figure independently of the text. As a result, the structure of the text and the English wording need to be reviewed.

Author Response

I am very grateful to your comments for the manuscript. According with you and other reviewer’s comments and suggestions, we amended the relevant part in manuscript, which are valuable in improving the quality of our manuscript. some notes as follows: 1. your comments is black font, and the reply is green 2. in the manuscript, the part that has been modified used red font 3. the reply please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript metals-746707-v1 has been submitted to the Metals journal for peer review as a research article. The title of this manuscript is:

“Effect of Warm Rolling Temperature on the Microstructure and Texture of Micro-carbon Dual-Phase (DP) Steel”

Motivation of this study is to investigate the influence of the warm rolling temperature on the microstructure and texture of C-Cr-Nb DP steel. The study has been carried on by advanced characterization techniques, including transmission electron microscopy, scanning electron microscopy and electron back-scatter diffraction. Microstructures and crystallographic textures of samples at different processing steps are measured and analyzed. Experimental procedure is rather clear and follows a logic order. Nevertheless, the manuscript is not well written. Experimental results are not exhaustively analyzed. Discussions are ambiguity and confuse. The current manuscript need to be substantially improved before it can be published. Detailed comments and suggestions are given as following:

• Line 13: Authors need to define or remind their definition of the “fraction and width of the deformation bands” before they can use this term through-out the manuscript.
• Line 14-15: There is an expressional error in the statement “The deformation band exhibited … when rolled at 450 °C.” Deformation band is a microstructural feature in deformed samples. On the other hand, what was rolled is a steel sample. Authors need to check and correct all similar ambiguous statements in this manuscript.
• Line 17-18: “ … the {112}<110> and {001}<110> are the main texture, and the γ-fiber exhibited the strongest intensity …” is a confusing statement. Readers will not understand what is the preferential orientation on this sample, the {112}<110> and {001}<110> orientations or the γ-fiber.
• Line 18-19: “After annealing, the density of the γ recrystallization texture first increased and then decreased with the increase of rolling temperature” is a confusing statement.
• Line 17-24: Readers will not understand what authors want to describe with this paragraph “As for the warm rolled texture… the deep drawing property.”
• Line 34: “… γ texture …” and all other crystallographic orientations need to be clearly defined before using in this manuscript.
• Line 42-58: Authors describe the dynamic strain aging (DSA) and its impacts on microstructure and texture of steel. Nevertheless, this phenomena is not further mentioned or applied the manuscript. Then readers would have a question on the role of the DSA on the current study.
• Line 72: “The hot rolled specimens were heated to a rolling temperature …” To which temperature did authors mean?
• Line 75: “… the SK-10-13H heat treatment system …” is unknown to general readers. Authors need to describe the system more than just put its name to the manuscript.
• Line 79: What do authors mean with “The microstructure and texture in the sample surface thickness regions …”?
• Line 90: Microstructure feature captured by SEM is not easy to observe in this manuscript. To investigate deformation microstructures, micrographs of etched samples obtained by optical microscope might be more suitable.
• Line 91: Since authors observed microstructures on the RD-ND plane, then I would say they measured the “thickness” rather than the “width” of deformation bands.
• Line 93: There is no clear evidence for “The block pearlite was broken during rolling …”
• Line 91-101: Authors described differences in microstructures rolled at various temperatures. Nevertheless, without quantitative measurement, all explanation will be subjective.
• Line 119: Authors did not mention how they conducted the texture measurements and which method they used to calculate the orientation distribution functions.
• Line 125-126: What do authors mean with the statement “The intensity of the γ-fiber after warm rolling was stronger than when rolled at room temperature except at 550 °C.”?
• Line 128: What are the γ-, α- and λ- fibers?
• Line 129: Is the {111}//ND a correct notation?
• Line 153-154: “Strong γ-fiber as well as strong {001}<110> and {001}<100> content were observed at room temperature”, in fact is not visible from the corresponding figure.
• Line 155: What do authors mean with “slight disappearance”?
• Line 163: Readers do not see “The {111} texture content first increased and then decreased …” as mentioned by authors.
• Line 190: What do authors mean with “… significantly higher texture factors …”?
• Line 194: All figures are too small to observe.
• Line 197-198: What do authors mean with “The temperature range of warm rolling is between room temperature and recrystallization temperature.”?
• Line 204: What are the “extremely high temperatures”?
• Line 207: Martensite forms during quenching but not “in the subsequent annealing process at 450°C” as authors mentioned.
• Line 225: What are the “slips between the dislocations”?
• Line 230: What is “The transition band between the {111} and <112> grains”?
• Line 231: “Precipitate interaction with the dislocation was more likely to occur at higher temperatures …” Why does precipitate not interact with dislocation at lower or room temperature, according to authors?
• Line 250-251: “However, the recrystallization texture was slowly formed at room temperature …” Does it mean recrystallization still occurs at room temperature but with a slow rate?
• Line 273: There is no evidence for “… a more uniform ferrite and martensite after annealing …”

 

Author Response

I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some of your questions were answered below. some notes as follows: 1. Your comments are in black font, and the reply in green 2. In the manuscript, the modified part is in red

Please see the attachment

 

Author Response File: Author Response.pdf

Reviewer 3 Report

The submitted paper considers the investigation of microstructure evolution of micro-carbon dual phase steel. Based on microstructure observations, deformation mechanisms were analyzed for the manufacturing process which include rolling and annealing steps. The paper is well written and is recommended to be printed.

 Some questions:

• In line 107, “the martensite grain size was large”, if the grain size of different phases (ferrite/martensite) were measured? Can you add the estimation results to the paper?

• In Figure 8, some colors (yellow, light blue/green) are difficult to see. Could you exchange them?

• In Table 1, the material composition is presented. Could you comment till which increase/decrease of Carbon concentration the defined deformation mechanisms during manufacturing process are equal. What changes can be expected with increase/decrease of carbon?

Author Response

I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some notes as follows: 1. Your comments are in black font, and the reply in green 2. In the manuscript, the modified part is in red 

A more detailed reply please see the attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

This is an interesting study looking into the rolling texture and microstructure evolution at different rolling temperatures. However, I feel the material could be presented more clearly and the introduction could be expanded. Below you will find my comments to your work. 

 

General comments:

• Change "solution C" to "C in solid solution".
• Use specimen or sample, not both interchangeably
• Add manufacturing name and/or references to all software and hardware used.
• Regarding description of textures based on the plots in Figure 4 and 6. Reference the figure more in the text. Describe which figure (a,b,c etc) as well as just mentioning the temperature. Make it easier to read the figures with the text.
• Make sure the results from the figures are properly described in the text.

Specific comments:

• Line 17: "the main texture" --> "the main texture components"
• Sentence on line 28/29: Meaning unclear. use warm rolling to improve both strength and drawing properties? Or comparing rolled steels with drawn steels?
• Sentence on line 34-36: Rewrite, hard to read and meaning unclear. Maybe split into two.
• Line 36/37: Han et al.
• Line 41: "IF" --> "IF steels", "low carbon (LC) steel" --> "low carbon (LC) steels"
• Line 49: remove "by"
• Line 53: remove "to"
• Line 60: "the evolution of the microstructure" --> "the microstructure evolution"
• Final paragraph in the introduction can be improved. More specific on your main object of the study, on how your work relate warm rolling and deep drawing.
• In introduction, define the texture fibers gamma, alpha and lambda
• Line 65: "rare earth" --> "rare earth (RE) elements"
• Sentence on line 66/67: Unclear, rewrite. What is the metal forged or just casted? What are these dimensions? Is it the crucible or the the final the dimensions of the casted specimen?
• Paragraph starting on line 69:
  • The first 4 sentences starts with "The...", rewrite
•  Paragraph starting on line 69:
  • Add specimen preparation for SEM micrographs and EBSD in addition to TEM.
  • Final sentence is to long. Split up and rewrite, add that the electrolyte is used for electropolishing. 
• Section 3.1:
  • add numerical value to width of deformation bands
  • Figure 2 caption: HR-RT-WR undefined
  • Remove bottom bar of SEM micrographs (FIgure 2 and 3) and create a scalebar instead.
• Sentence line 127-130: Very long, rewrite.
• line 131: 22% of the gamma fiber present at 450C? Clarify
• line 151 caption: and missing between the two orientations for Figure 5a
• line 175: highest --> strongest
• line 217: What resistance, resistance to change?
• Paragraph starting 225: describe figures more. What is seen in the figures and how does it relate to the text? 
• line 239: statement on the end. What is this based on? Need to refer to your results or citation.
• Paragraph 245: Vary language, many sentences have the same structure and start the same. However, Therefore, however, however...
• Sentence line 246-250: Too long, rewrite
• line 249: remove surrounding, redundant
• line 263: temperature --> specimen at, than --> compared to the specimen
• line 264: Figure 11c is referred to in the next sentence
• Conlusions
  • 1) Rewrite to be more clear and concise. 
  • 2) Vary language, all three sentences start the same: the...
  • 4) why is re-dissolution underlined?

 

Author Response

I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some notes as follows: 1. Your comments are in black font, and the reply in green 2. In the manuscript, the modified part is in red  A more detailed reply please see the attachment

Author Response File: Author Response.pdf

Reviewer 5 Report

The paper is clear and well written

My once concern is about the references section: the majority of them are old references. I suggest to add some more more recent reference.

Author Response

I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript.some notes as follows: 1. Your comments are in black font, and the reply in green 2. In the manuscript, the modified part is in red A more detailed reply please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The manuscript metals-746707-v2 has been resubmitted to the Metals journal for peer review after major revision and correction.

As compared to the previous one, this second version of the manuscript is substantially improved. Authors have shown significant efforts on analyze research results better and present the manuscript in a clearer way. The manuscript, however, has not been ready to be published. Language and grammar in this paper need to be through-out and more carefully checked. Scientific terms and notations must be validated so that misunderstanding could be completely eliminated. Studied results need to be better presented so that discussion and conclusion on the investigation are more robust and objective.

More specifically, authors show microstructures of warm rolled samples at different temperatures obtained by SEM as the first evidence for the occurrence of dynamic strain aging. However, as previously commented, micrographs shown in Figure 2 is not well contrasted for visualization. Thickness measurement of deformation bands in these micrographs is rather arbitrary. In the same manner, microstructures are given in Figure 3 without any indication on how readers could differentiate between ferrite and martensite, deformed and recovery/recrystallized microstructure.

Crystallographic texture is presented as the key feature in this manuscript, but there is no information on how authors measured the texture, how they compare and calculate fraction of different texture components, or at least the area of the measurement … Additionally, if the ratio between volume fractions of the γ-fiber and α- and λ-fibers is at its maximum of 1.0 at 450 °C, as authors indicated, then the γ-fiber is not really the most preference texture component. On the other hand, to have “the optimized deep drawing properties”, it is necessary to obtain a homogeneous γ-fiber texture in the material. However, as can be observed in Figure 6d and Figure 7b, intensities of the {111}<112>  and the {112}<110> orientations are both two time higher than that of the {111}<110> orientation. Therefore, readers will not be convinced by “the optimized deep drawing properties” with this inhomogeneous texture.

Author Response

I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some of your questions were answered below. some notes as follows: 1. Your comments are in green bold font, and the reply in black 2. In "final version-manuscript", the modified part is in red Please see the attachment

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

The manuscript is significantly improved now. Its quality already reaches the level for a publishable document. Just a minor recommendation that authors need to check and correct all Miller indices which are used in the documents. Notation for crystallographic planes is different for axes. For examples, in line  89-90, the right notations should be <110>//RD, <111>//ND and <100>//RD, instead of {110}, {111} and {110}.

Author Response

Dear Reviewer,

Thanks again for your review of the manuscript. According to your comments, the

authors have carefully checked and made some modifications in manuscript (track

version), which is respectively in lines 89-90,144,232,279 and 281. Please review it.

some notes as follows: 1. In "track version-manuscript", the modified part is in red

Please see the attachment.

Any questions please contact me asap! Thank you so much for your kindly help!

Best wishes

Corresponding author: Zhigang Wang

 

Author Response File: Author Response.pdf