Comparative Evaluation of Coated Carbide and CBN Inserts Performance in Dry Hard-Turning of AISI 4140 Steel Using Taguchi-Based Grey Relation Analysis

Round 1

Reviewer 1 Report

This paper is a good presentation of investigating the several factors in dry hard turning of a hardenable Cr-Mo steel. The parameters include cutting speed, feed, depth, and nose radii. The authors have tried to make a comprehensive range of parameters for their analysis. However, the way to present such an amount of parameter variables makes the reader confused. The paper can be published after making modifications as below:

1. Table 1 is an extremely large table that belongs to the overview of former literature in this field. I believe that you don't need to present so intensively and I suggest modifying Table 1 to make it shorter. For example, it's not necessary to add all results of each paper in long sentences. It's better to summarize the results of each work in the introduction and summarize various parameters in the table only. I highly recommend making Table 1 shorter.

2. You have mentioned the surface roughness of samples after machining. It would be beneficial to present one example of the raw data and add it to the end of Materials and Methods when you describe the surface roughness data analysis.

3. Due to the size of the graphs, the y and x-axis numbers are too small in Fig. 2, 3, 4, and 6. It makes the figures easier to see for the reader if you increase their font.

4. Finally, the authors have summarized their findings on the effect of various parameters in the Conclusion part. However, the data lacks some reason why these results have been obtained. For example, you have reported that the best surface quality was obtained using a CBN insert with 0.28mm and with a high cutting speed and low feeding rate. But you didn't explain that why these parameters affect getting the best surface quality. Does it have anything to do with the microstructure? hardness? This lack of explanation about "Why?" exists in your conclusion. It would be better to have a more deep explanation of the phenomenon resulting in these effects.

Overall English of the manuscript seems acceptable.

Author Response

The response to the reviewer's comments is attached.

Author Response File: Author Response.doc

Reviewer 2 Report

Notes in the attachment.

Comments for author File: Comments.pdf

Author Response

The response to the reviewer's comment is attached.

Author Response File: Author Response.doc

Round 2

Reviewer 1 Report

I appreciate the attempts of the authors to apply modifications to your manuscript. Your work is suitable for publication and contains a good review of former literature in this field.

The English content of your manuscript is appropriate.

Reviewer 2 Report

The authors have made corrections to the article. Thank you.