Modeling Thermomechanical Stress with H13 Tool Steel Material Response for Rolling Die under Hot Milling
Round 1
Reviewer 1 Report
The authors should make an effort to compare their approach to those already published.
The authors mentioned tribological factors: did the authors take into account of the coefficient of friction? The authors wrote : page 3 : '... heat loss due to radiation and convection and heat gain due to friction are often neglected because the significance upon the temperature change are small at given rotational time rate, relative to the other parameters.' Yes, but from a mechanical standpoint, the friction is important because it leads to shear stress in the rolls.
The modeling is only considering elastic deformation even though the authors proposed the equation 20... this expression being that of an elastic deformation.
The equation 21 assumes that the total deformation is equal to zero, which thus, in this particular case, enabled to calculate an plastic deformation corresponding to a material with an elastic-perfectly plastic behavior, i.e., no hardening.
The authors could rewrite the sentence page 8: 'The circumferential stress is equal in magnitude to the yield stress during plastic deformation (elastic-perfectly plastic material)'
Where does the equation 32 come from?
Remarque: a linear relation to describe the variation of the UTS and yield strength seems to overestimate the room temperature properties... and thus probably the residual stresses.
The applied conditions leading to the results of simulations presented in Figures 3 and 7 are missing.
Are the authors sure about the unit in Figures 13 a) and b)???
Why do the authors use the term progressive damage in page 20 lines 1-2, while no results are shown! Indeed which damage model was used: Gurson damage model?
Page 20 : 'The plastic damage occurring on rolling die surface have been characterized as a function of temperature and loading history.' Where are these results presented?
English:
Page 1 : excited???
Page 3 : the following sentence should be rewritten : 'In terms of the geometrical configuration and the analysis is done by considering infinite-width of the rolling die, the rolling die is rotating at constant angular speed and subjected to a constant heat flux q0, convective cooling (with constant heat transfer coefficient hw) over sector q, over the angular sector a and g is the relative angular distance between the two regions above indicated.'
Page 5 : Although analysis of 3D problem is possibles...
Page 6 : 'Regarding the procedure of measurement were data recording see [18,19].'????
Page 7 : Somehow, it seems dual mechanism damages.????
Page 12 : Normal and shear loading on the rolling die’s surface... die’s???
Page 13 : numerical (not numeric), experimental (i missing) also in Figure 7
Page 14: Hooke's law (not Hooks hooke's constitutive...)
Author Response
Many thanks for your constructive comments. Regarding the response of the comments file is attached find it.
With Regards,
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript presents a model for the thermomechanical stresses in H13 die milling. The model is laregely numerical. Details about the experimental verification of the model would improve manuscript. The equations must be grouped tighter and only the high level ones should be presented.
Author Response
Many thanks for your constructive comments. Regarding the response of the comments file is attached find it.
With Regards,
Author Response File: Author Response.pdf
Reviewer 3 Report
In the article entitled “Modeling Thermo-Mechanical Stress with H13 Tool Steel Material Response for Rolling Die under Hot Milling” a model that consists of five sub-models is presented. The first sub-model describes the temperature distribution on the rolling die surface by accounting for the effects of different process parameters such as the initial temperature of the slab, reduction ratio and the rolling speed. The second and third models describe the thermal cyclic stress and the elasticity deformation of mechanical stress, respectively. The fourth sub-model describes TM stress generation through inheriting numerical approaches. The last sub-model is developed for the H13 tool material response at high temperature. The model includes new proposed constitutive equations for temperature distribution, thermal cyclic stress under the application of continuous cast process, etc. To verify the model, finite element simulation and experimental data are considered. The results show good agreement between finite element simulation and experimental data.
The paper is interesting and can be accepted for publication.
However, some editing of the English language and style is required.
Author Response
Many thanks for your constructive comments. Regarding the response of the comments, a file is attached find it.
With Regards,
Author Response File: Author Response.pdf
Reviewer 4 Report
The article discusses the modeling thermo-mechanical stress for rolling die under hot milling.
Unfortunately, the reviewer cannot recommend this article for publication in its current form. Below are the comments of the reviewer.
According to the reviewer, at least the first two phrases in the Abstract are redundant. Abstract should convey the main meaning of the article (tasks - solution path - results) in a concentrated form. In the Abstract there is no point in communicating information, which, as a rule, is well known to specialists.
The proposed modeling is based on a number of assumptions that need to be clearly defined (for example, the material of gain due and hot slab are assumed to be isotropic, coolant flow constant over time (although in fact this is not the case).
Also, there are chemical interactions (for example, oxidation), diffusion processes, and a number of other factors. Perhaps they can be neglected, but in this case at least, their insignificant influence on the process should be justified.
“comparison between the numeric and finite element simulation” - Strictly speaking, the finite element method is also a numerical method.
Figure 7 - by what method are the "experimental" values obtained? Where is the description of this method? Everything is so well matched (especially experimental and calculated values) ... very beautiful ... but is it reliable? If the experimental data do not belong to the authors, it is necessary to indicate this also in the caption inscription.
Not sure if Table 1 is needed (this data is well known and publicly available)
Unfortunately, the lack of experimental confirmation of the adequacy of the developed models significantly reduces the value of the results obtained. In essence, the results of two variants of numerical modeling are compared (the finite element method and the method proposed by the authors). The results obtained are also compared with the experimental data of other authors.
Since the proposed numerical model itself is built on a large number of assumptions (and simplifications), it cannot be accepted without a clear and uniform test of its adequacy to the real experimental data. The authors refer to the complexity and high cost of experiments. This is true, but, unfortunately, cannot justify the absence of experimental verification.
Author Response
Many thanks for your constructive comments. Regarding the response of the comments, the file is attached find it.
With Regards,
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Could you write the equation (9) on a single line?
In my first review, I wrote: The authors could rewrite the sentence page 8: 'The circumferential stress is equal in magnitude to the yield stress during plastic deformation (elastic-perfectly plastic material)'
This sentence appears in page 9 (first sentence). Indeed, the figure 4 clearly shows an elastic-perfectly plastic behaviour between point C and point D. (The behaviour between the point A and B reflect the variation of the yield strength with the temperature).
But this Figure 4b is probably on schematic diagram only. So please indicate it in the legend.
Also Figure 4 only show the mechanical stress-strain behaviour and there is no damage in Figure 4: Thermal damage behavior under cyclic load. (a) Stress phenomena during heating and cooling, (b) Stress and strain closed loop for a point on the rolling die surface
In the previous review (Reviewer Comment Point Seven)
7. Remarque: a linear relation to describe the variation of the UTS and yield strength seems to overestimate the room temperature properties... and thus probably the residual stresses.
If you look at the Figure 13, particularly that of the yield strength, you can see that the experimental points tend to follow a polynomial function rather a linear curve. This means that a T = 25oC, the estimated yield strength is overestimated if you used a linear variation of the yield strength with the temperature (the residual stresses being measured at room temperature).
In the previous review (Reviewer Comment Point Ten)
10. Why do the authors use the term progressive damage in page 20 lines 1-2, while no results are shown! Indeed which damage model was used: Gurson damage model?
Response: In fact, some terminologies have a meaning in context. The result of progressive damage (cyclic contact damage) are clear represented in Figure 15 and 16 depending on the a given number of cyclic loads. In short, it is not about Gurson damage modeling or crack propagation, etc.
But shall the reader understand that the damage is defined as the ratio N/Nf? and that you assume a linear damage rule? Sorry, it is not clear how the damage is defined in your manuscript. You wrote:
Results show progressive damage and failure in the material based on a continuum damage mechanics approach and linear
elastic fracture mechanics, in which case damage initiation and evolution are characterized by the accumulated inelastic stress energy per stabilized cycle.
In Figures 15 & 16, the reader can only see Stress and temperature. If you use the continuum damage mechanics approach, you should have a D parameter in your constitutive equation, and if you calculate it, please show its variation with time (on number of cycle). If you use elastic fracture mechanics, it should appear as a crack length...
In the previous review (Reviewer Comment Point Eleven)
11. Page 20 : 'The plastic damage occurring on rolling die surface have been characterized as a function of temperature and loading history.' Where are these results presented?
Indeed you don't mention Figure 16 in the text...
English:
Introduction
page 1 : ... metal to metal contact whose motions interdependent.
... and they must be ground... (grounded)
Author Response
Regard the response to reviewer comments, the file is attached find it.
Author Response File: Author Response.pdf
Reviewer 4 Report
Since the authors have done a great job of changing the article, now this work is much more acceptable for publication. At the same time, the reviewer maintains his recommendations on the need to thoroughly check the adequacy of the model. This will need to be done in the subsequent works of the authors. There, however, this article can be recommended for publication, as it represents a fairly fresh look at the modeling questions of thermo-mechanical stress for rolling die under hot milling.
Author Response
Regard the response to reviewer comments, the file is attached find it.
Many Thanks for your Time.
Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
The manuscript is acceptable for publication.
