Physical Modelling of the Ball-Rolling Processes
Round 1
Reviewer 1 Report
In the article entitled “Physical Modeling of the Ball-rolling Processes” the state of the problem of physical modeling of the hot-working processes with plasticine as the model material is presented. The comparison of the test results regarding shape and manufacturing accuracy as well as force parameters confirmed the validity of using physical modeling in the investigation of the process of cross- and helical rolling of balls.
This paper, although lacks originality, presents some well-done experimental work and useful conclusions and can be accepted for publication.
Author Response
Thank you for the positive assessment of the article.
Reviewer 2 Report
The authors presented a physical model of ball-rolling processes, which resort to plasticine as model material and scaled models for the forming tools, as an alternative to finite-element modeling and analysis.
The manuscript is suitable to be published in Metals after addressing the following remarks:
(i) English should be revised
(ii) 2 - Materials and Models: the constitutive model should be described; the constants of the model concerning black and white plasticine and steel grades should be indicated in a table, instead of equations.
(iii) The authors mention the advantage of the physical model over FEM-based numerical analysis. What if another type of material was used instead of C40 or C45 steel? Would it require a new physical model of the process?
Author Response
i) The article was subjected to a re-examination, as a result of which linguistic mistakes were corrected.
ii) As suggested by the Reviewer, the constants describing constitutive equations were listed in Tables in the article.
iii) Using another grade of steel for the model testing will require obtaining similarity coefficients between the model material and the chosen steel grade, which is not overly labour-consuming.
Reviewer 3 Report
This manuscript represents the experimental and numerical analysis of hot metal forming using plasticine. Real cross rolling and helical rolling forming were used to confirm the results. The structure of the paper is well organized and the overall paper tells a logical story with a concrete conclusion. It is suitable for publication in Metals after minor revision. Reference section should be improved with published works related to experimental and numerical analysis of metal forming (computational plasticity), as for example:
[1] M.A. Caminero, Experimental Study of the Evolution of Plastic Anisotropy in 5754 Al-Mg Cold Rolled Sheets, Experimental Techniques 39 (2015), 35-42
[2] M. Miñano, M.A. Caminero, F.J. Montáns, On the numerical implementation of the Closest Point Projection algorithm in anisotropic elasto-plasticity with nonlinear mixed hardening, Finite Elements in Analysis and Design 121 (2016) 1-17
Author Response
Out of the suggested publications the authors selected one, which was compliant with the subject matter of the article.
Reviewer 4 Report
The manuscript presents an interesting subject of producing spherical balls. The authors focus on the production of steel and plasticine balls. The manuscript has a small amount of modelling and experimental results with only a small contribution to knowledge.
Author Response
Please find the detailed response in the attachment.
Author Response File: 
Author Response.pdf
Reviewer 5 Report
In equation (6), the term epsilon (effective strain) was integrated between 0 and 1. The term epsilon is the effective strain, as defined in Eqs.(1) et (2), isn't it. Why did you integrate up to 1, while critical values were found equal to 0.786 and 1.134 (line 121) for white and black plasticines, respectively?
References:
The names of the reference 1 are wrong: Q.X. Wang, Q.P. Wang, J.M. Xiao
The manuscript requires English editing. For example: Modeling (American English) is used in the title and in the text while we can found modelling (British English) in lines 17, 100, 105 and 314. Some sentences could be corrected:
line 8 : article's objective -> objective of the article
line 33 : In said process ???
line 44 : An example of this are the works created in Japan...???
line 66 : that guarantees obtaining a forging of the expected geometry ???
line 67 : ... used plasticine in obtaining the parameters of the forging process which guarantees the right shape ???
line 115 : The model material was also subject to testing that... ???
line 126 : coefficient of friction
line 128 : It was presumed that ... the value of the coefficient of friction equaled 0.8.
line 170 : ... the ball rotation axis...
line 196 : The aim of the guiding device is to keep... (indeed you should better used the past tense...)
line 209 : ... due to them being 1:2.5...???
Author Response
The values from 0 to 1 are the values of strain. Equation 6 was applied in order to obtain the similarity coefficient between the steel and plasticine flow curves. The values mentioned by the Reviewer are the limit values of the Cockroft-Latham integral, not identical with the values used in equation 6. In the case of uniaxial tension they are similar to the values of the maximum strain in this process. The subject of the analysis were, however, processes of cross and skew rolling , where the values of strain are different. Thus, it was arbitrarily decided that in the process of obtaining the similarity coefficients flow curves to strain ranging from 0 to 1 will be used.
Thank you for indicating the mistake in the name description in References.
The article was subjected to a re-examination, as a result of which linguistic mistakes were corrected.
Round 2
Reviewer 2 Report
Accept
Reviewer 3 Report
Accepted in present form
Reviewer 5 Report
This version of the manuscript can be accepted for publication.
