The Effect of Flow Lines on the Mechanical Properties in Hot-Rolled Bearing Steel
Round 1
Reviewer 1 Report
- The title of the article is incorrect because "... anisotropy of mechanical properties ..." has not been proven
- Tab.1. The gas contents are missing (Nitrogen, Oxygen)
- Fig.1 c: The orientation of the samples for the etched surface is inappropriate. The best observation of structural development would be when the surface was observed across the thickness of the sample.
- The whole chapter 3.1 has a very untrustworthy character, because the orientation of the sample for metallographic observation is inappropriate.
- Line 187: The evaluation of plastic properties via elongation is not accurate. A better evaluation of plastic properties is by help of reduction of area. What was the reduction of area for the observed states?
- Fig.11: The observation resulting from Fig.11 cannot provide an answer to the recrystallization process. Question: has the structure been recrystallized? Can the authors have confirmed the recrystallization progress?
- Line 259: The authors' statement "carbides affect grain deformation and rotation, as shown in Figure 11g." is not supported by the EBSD observation. The evaluation of the grain rotation from Fig. 11g without scientific confirmation is not acceptable.
- Authors have to add microstructural observations along the sample thickness.
Author Response
Response to reviewer #1
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article contributes with an experimental characterisation of the microstructure and tensile properties of a hot-rolled bearing steel. The article is generally well written and the topic interesting, which both suggest possible publication. Below some major comments regarding specific points and others minor comments mainly focused on the clarity of the manuscript or misprints.
Figure 1a It seems that the specimen geometry used in tensile tests is different from the geometry prescribed by international standards (ISO). Please justify this point and explain whether the particular geometry used may have some effect on the results of tensile tests;
Line 114-115 the text introduces the concept of dark flow-line zone and light flow-line zone, but it is not clear whether these are properties and definitions used generally in the literature, or they are simply definitions introduced by the Authors. In the latter case, the definition must be explained to avoid ambiguity;
Figure 3 the single images are too small, please increase and reorganise the layout of this figure;
Figure 5 In a black/white print, the colours used for the two data are virtually indistinguishable. Please increase the contrast so that the bars of different data appear more clearly;
Line 185-187 It seems that the conclusion mentioned in these lines appears to have general validity for metallic materials (i.e. 90° properties are lower than 0° properties). The Authors should link they conclusion to other studies from the literature, also not necessarily related to bearing steels
Figure 8 please increase the figure size;
Line 195 and 337 The text says that 0° samples are ductile, whereas 90° are brittle. This statement is rather questionable is one looks at Figure 8, in which both types of specimen have elongation >30 (such a large elongation cannot identify a brittle material). A different explanation should be given in the text in place of “brittle”;
Figure 9 It is rather hard to understand which figure refer to 0° and which to 90°. For more clarity, these angle values should also be places in the images;
Sec 4.2.1 It seems that the three equations (1), (2), (3) are never applied in the rest of the text. Therefore, they should be deleted, unless they are used somewhere with the experimental data presented in the previous sections of the paper;
Line 404 to 431 This text section must be completed by the Authors;
Minor issues
Line 95 “The samples with flow lines of size of 5x5x10 mm” sounds strange or ambiguous. Do the Authors mean that there are flow lines of 5x5, or they refer to the geometry? Please rephrase the sentence;
Line 103 “…the examination, The samples…” must be “…the examination, the samples…”
Line 114 “The flow lines of the samples are consisted of the…” is “The flow lines of the samples consisted of the…”
Lines 192-194 Maybe a misprint is present in the angles, because 0° is written twice despite the sentence uses “whereas” to contrast two situations. Please check;
Author Response
Response to reviewer #2
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors did not comment on the remark concerning the reduction of the area as a parameter for the evaluation of plastic properties of material.
Author Response
Response to reviewer #1
Author Response File: Author Response.pdf
