Improving the Wear Resistance of Ledeburitic Tool Steels by a Combination of Semi-Solid and Cryogenic Processing
Round 1
Reviewer 1 Report
The article has a scientific character. The article deals with the wear properties and microstructure of X210Cr12 steel after cryogenic and thermomechanical treatment. The Authors applied correct research methods and used the appropriate measuring equipment. The content of the work is logically written. The manuscript contains 16 figures and 4 tables. Figures and tables aren't properly prepared. Authors cited 31 literature sources.
The authors presented an interesting work, but it requires improvements to be of satisfactory quality.
General remarks
1. Specify the data of the apparatus in the article in the following order: device designation, manufacturer's name, city, country.
2. In general, improve the discussion of the results obtained
3. Give your conclusions in the form of points
Detailed comments
1. Figure 1a - indicate the individual phases on the drawing
2. Figure 3 list the heating and cooling rates in the figure
3. Figure 4 - indicate the individual phases on the drawing and provide the average grain diameters in the description below
4. Figure 5, 6 - indicate the individual phases on the drawing
5. Table 4 Add grain sizes after individual treatments in the table, and also enter the measurement uncertainty in the results
6. Figure 15, 16 Add error bars
Author Response
Dear reviewer,
thank you very much for your helpful comments and suggestions. Responses to the comments are embedded for each point; see below.
- Specify the data of the apparatus in the article in the following order: device designation, manufacturer's name, city, country.
Data were added to the text for each instrument.
- In general, improve the discussion of the results obtained
I tried to improve the discussion of the results achieved. The changes are listed in the text.
- Give your conclusions in the form of points
The conclusion was rewritten into points.
Detailed comments
- Figure 1a - indicate the individual phases on the drawing
The phases were marked in the figure.
- Figure 3 list the heating and cooling rates in the figure
The heating and cooling rates were added to the figure.
- Figure 4 - indicate the individual phases on the drawing and provide the average grain diameters in the description below
The phases were marked in the figure. The grain size was added to the text related to the image.
- Figure 5, 6 - indicate the individual phases on the drawing
The phases were marked in the figure.
- Table 4 Add grain sizes after individual treatments in the table, and also enter the measurement uncertainty in the results
The grain size was added to the table as well as the uncertainty in the results.
- Figure 15, 16 Add error bars
Error bars were added, and the figures were replaced in the text.
Reviewer 2 Report
This paper reported the wear resistance improving of a Ledeburitic tool steel by semi-solid forming and cryogenic process heat treatment.
1. The detailed composition of test steel should be added(line 89-line 90)
2. Tables (such as Table 2 , Table 3) should be modified、Variables should be italicized.
3. English writing could be improved.
Author Response
Dear reviewer,
thank you for your review and comments.
- The table has been added to the text.
- Tables 2 and 3 have been modified.
- The article has been corrected by a native speaker.
Reviewer 3 Report
Dear authors,
the present paper describes a very interesting method of semi-solid processing of ledeburitic tool steel with the ambition of a positive impact on materials properties, particularly wear resistance. The scientific quality of your work would strongly benefit from considering the following aspects:
1. page 2, line 50: The carbides you refer to are not "primary" but rather "eutectic".
2. page 2, line 52: A semi-solid state alone does not provide thixotropic behavior. In addition, a proper pre-processing of the material is necessary to obtain a full separation of liquid and solid during semi-solid processing.
3. page 2, line 24: "processing processes" should be replaced by "processing methods" and on page 1, line 40: "hardfacing" written without "e".
4. page 2, lines 69-77: DCT stands for deep cryogenic treatment. In addition, I do highly recommend to be more careful with statements on DCT directly taken (and accepted as true) from literature. Particularly, formation of (nano) carbides during DCT is not plausible due to insufficient carbon diffusivity, even though tempering time at DCT temperature does exert a measureable influence on properties.
5. page 4, lines 135-143: More details must be provided on the deformation including the resulting degree of deformation. The statement "... were deformed from all sides" is not clear to the reader.
6. page 4, lines 149-155: The font size seams to be too small, furthermore it is not clear, why you tempered at 300°C. This temperature is not common for X210Cr12.
7. Some characters and indices are not subscripted, please check the whole document. page 6, line 208: the µm instead of um.
8. page 7, line 229: supercooling or undercooling instead of subcooling
9. Fig. 6: Micrographs are too dark and of low contrast, please improve.
10. page 12, line 395: "Indenter" seams to be the wrong expression.
11. Table 4 (plus text accordingly): The soft-annealed initital state is not the proper condition to compare your semi-solid results with. Instead, the conventionally heat treated (1080/oil + 200 or 300°C/air) state of X210Cr12 must be the reference. Furthermore, you should include a table with the full chemical compositions of X210Cr12, Hardox 450 and Hardox 600 plus the corresponding alloy costs per kg (and if possible the specific CO_2 or energy footprints of each of them).
12. The major detracting point of you work refers to the conclusions. Of course, every scientist is interested in highlighting the positive and successful aspects of his work. However, if you propose that your semi-solid processed X210Cr12 is a potential solution for liners or crushers, significant gain in performance and costs must be considered. The difference in wear resistance, particularly in sand-blasting, are not as high as I would have expected. Furthermore I doubt that your approach will be competitive against Hardox considering the tremendous effort spent into semi-solid processing and DCT. Communicating this in an honest manner would improve the quality of your work.
Author Response
Dear reviewer,
thank you very much for your helpful comments and suggestions. Responses to the comments are embedded for each point; see below.
- page 2, line 50: The carbides you refer to are not "primary" but rather "eutectic".
The designation was changed in the text.
- page 2, line 52: A semi-solid state alone does not provide thixotropic behavior. In addition, a proper pre-processing of the material is necessary to obtain a full separation of liquid and solid during semi-solid processing.
Yes, you are right. It is necessary to get a suitable solid particle shape in addition to the required melt ratio.
The text was edited to:
Due to the presence of melt and with the appropriate size and shape of the solid particles, the material exhibits thixotropic behaviour, which allows producing shape complex parts in one forming step, to form even more difficult to form materials and to use lower forming forces than in conventional forming technologies [13-16].
- page 2, line 24: "processing processes" should be replaced by "processing methods" and on page 1, line 40: "hardfacing" written without "e".
Thank you. Changed in text.
- page 2, lines 69-77: DCT stands for deep cryogenic treatment. In addition, I do highly recommend to be more careful with statements on DCT directly taken (and accepted as true) from literature. Particularly, formation of (nano) carbides during DCT is not plausible due to insufficient carbon diffusivity, even though tempering time at DCT temperature does exert a measureable influence on properties.
Thank you for your comment. The text was modified.
- page 4, lines 135-143: More details must be provided on the deformation including the resulting degree of deformation. The statement "... were deformed from all sides" is not clear to the reader.
A drawing of the forming process was added to the text.
- page 4, lines 149-155: The font size seams to be too small, furthermore it is not clear, why you tempered at 300°C. This temperature is not common for X210Cr12.
Thank you for the comment. The font was actually smaller in this paragraph. Corrected.
The tempering temperature was selected based on recommendations from material data sheets, literature and experience.
The following text was added to the manuscript for clarification:
The temperature of 300 °C was chosen based on information from the material data sheets [26,27] and temperatures reported in the literature [27]. Since an attempt was made to reduce the very high hardness obtained after semi-solid processing, a temperature of 300 °C was used, which resulted in lower hardness values.
https://steelselector.sij.si/steels/OCR12.html
https://www.finemetal.ro/wp-content/uploads/2020/09/1.2080-CP10V-X210Cr12.pdf
Jovičević-Klug, P., Jovičević-Klug, M., Sever, T., Feizpour, D., & Podgornik, B. (2021). Impact of steel type, composition and heat treatment parameters on effectiveness of deep cryogenic treatment. Journal of Materials Research and Technology, 14, 1007–1020. https://doi.org/10.1016/j.jmrt.2021.07.022
Jirková, H., David, A., & Bohuslav, M. (2010). Unconventional structure of X210Cr12 steel obtained by thixoforming. Journal of Alloys and Compounds, 504(SUPPL. 1), S500–S503. https://doi.org/10.1016/j.jallcom.2010.02.137
- Some characters and indices are not subscripted, please check the whole document. page 6, line 208: the µm instead of um.
Thank you for finding the typo. The document was checked and the errors were corrected.
- page 7, line 229: supercooling or undercooling instead of subcooling
It was changed to undercooling
- Fig. 6: Micrographs are too dark and of low contrast, please improve.
The images were changed.
- page 12, line 395: "Indenter" seams to be the wrong expression.
It was changed to a pin.
- Table 4 (plus text accordingly): The soft-annealed initital state is not the proper condition to compare your semi-solid results with. Instead, the conventionally heat treated (1080/oil + 200 or 300°C/air) state of X210Cr12 must be the reference. Furthermore, you should include a table with the full chemical compositions of X210Cr12, Hardox 450 and Hardox 600 plus the corresponding alloy costs per kg (and if possible the specific CO_2 or energy footprints of each of them).
The chemical compositions of X210Cr12, Hardox 450 and 600 were added to the text. The results of the conventionally processed sample from the sandblast test were also added. Conventional processing was carried out based on data obtained from the material sheets. The obtained structure and hardness value were also added to the articles.
Unfortunately, I am currently unable to complete the carbon footprint and other information. This research has focused on further research into semi-solid processing technologies, and research will continue to focus on simplifying the process and reducing the overall processing effort.
- The major detracting point of you work refers to the conclusions. Of course, every scientist is interested in highlighting the positive and successful aspects of his work. However, if you propose that your semi-solid processed X210Cr12 is a potential solution for liners or crushers, significant gain in performance and costs must be considered. The difference in wear resistance, particularly in sand-blasting, are not as high as I would have expected. Furthermore I doubt that your approach will be competitive against Hardox considering the tremendous effort spent into semi-solid processing and DCT. Communicating this in an honest manner would improve the quality of your work.
Thank you so much for your comment. I have modified the conclusion.
Of course, I realize the greater time and economic demands of semi-solid processing. This research should show one of the other possibilities to obtain a material with higher wear resistance. This research will be continued to produce a much larger semi-product from which a larger number of parts can be produced. This could lead to at least a partial reduction in costs.
Round 2
Reviewer 3 Report
No further comments.
