An investigation of the Temperature Distribution of a Thin Steel Strip during the Quenching Step of a Hardening Process
Round 1
Reviewer 1 Report
The LBB bath was used with laminar flow in model. It is question if real flowing around edges of sheet is laminar or turbulent. This can be reason why the result of model and real temperature field of sheet is different. It may be discussed to improved clarify this research.
Author Response
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Author Response.pdf
Reviewer 2 Report
The mathematical model and numerical simulations are at a high level. The simulation results are completed by validation experiments using an infrared thermal imaging camera.
1/ Some experimental data are needed. What is an austenitizing temperature, austenitizing time, ccoling rates, liqiud bath temperature, strip thicknes, etc. ?
2/ How the liquid bath affects a surface and corrosion resistance of the stanless steel ?
3/ Some references and related discussion are needed to compare the obtained results to numerical results on similar approaches in the literature.
4/ The conclusions 4 and 5 are too long.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
1. Clearly state the novelty aspects of the paper;
2. The presented results are based on real process conditions at Voestalpine. It means that the results were therefore presented in relation to a given design of heat treatment equipment. The authors did not analyze the test results for possible changes in the design of these devices so as to eliminate the occurrence of significant differences in the temperature distribution. Such analysis is necessary for the general application and not only for the process being studied.
The authors took a very brief look at the effect of differentiation of the temperature distribution on the shape of the strips. It is known that thermal processes lead to the formation of internal stresses in the sheets and often to the defects of strips. It is interesting how this temperature distribution will affect the stress distribution in the sheets. There is a lack of such analysis in the paper.
3. Current conclusions are rather a summary and not conclusions from research. In the current version the conclusions present a repetition of the obtained results. There is no interpretation of these results from the application point of view. There is a necessary to modify them.
4. Paper includes a few flaws, for instance: ”Flastness” instead of Flatness in Introduction section, or „The Temperature” instead of The temperature in section 4.3.
5. English must be checked.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Numerical analysis (laminar fluid flow and heat transfer) of continuous hardening process, which is mainly used to produce important stainless steel thin strip parts, is performed in this work. The explanation of the process is lucid as wells as numerical results and comparison with infrared thermal imaging results.
Here are some point for improvements of the manuscript :
Authors provided size of meshes in the mesh refinement study, can they also provide CPU times for each mesh, the computational architecture they have used, and if they have used any parallel capabilities of the COMSOL software
Figure 2 is not clear. Different colors should be used to distinguish position of strip and gliding material in the 3D domain.
Quantitatively numerical results match measurement from infrared thermal imaging, but qualitatively they don’t at the edge of the strip. Some suggestion for improvement of numerical model should be discussed, not necessary done in this work, such as :
Are constant values for convective heat transfer appropriate, or some calculation on calculated field variables should be embedded ?
How Re number was calculated (wrt to which dimension) ? Could it be locally turbulence effects and can they be modeled with some high level turbulence models such as k-Eps ?
How boundary conditions can be improved ?
Anything else ?
Numerical modeling of metal processes on elevated temperature has been extensively done, particularly for continuous casting of steel, that includes microstructure, heat transfer as well as physics coupling including nonlinear thermos-mechical behavior in solid parts, that authors refer to as possible extension thermomechanical analysis of strip. So, the authors should cite some of those works too:
Rappaz, M, Modelling of microstructure formation in solidification processes, International Materials Reviews Volume 34, Issue 1, 1989, Pages 93-124
Choudhary, S.K., Mazumdar, D Mathematical Modelling of Heat Transfer Phenomenain Continuous Casting of Steel., ISIJ InternationalVolume 33, Issue 7, 1993, Pages 764-774
Koric, S., Hibbeler, L.C., Liu, R., Thomas, B.G., Multiphysics model of metal solidification on the continuum level, Numerical Heat Transfer, Part B: Fundamentals 58(6), pp. 371-392
Author Response
Please, see separate document.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
In my opinion, the article should be transparent to all readers and refer to general knowledge rather than narrowing down to one technology. Therefore, I think that on the basis of the results obtained for this line, the authors should propose general guidelines, and at least indicate what can be improved. In my opinion, the improvement of the conclusions is crucial. These conclusions are a repetition of statements from the results of the research. The responces provided by the authors indicate that they have completely disregarded my comments. Therefore, I can not accept this paper in the present form. I can reconsider again after major revision.
Author Response
The conclusion has now been rewritten in accordance with the reviewer’s comments. More specifically, general guidelines for how the methodology can be applied for continuous heat treatment processes have been provided. Furthermore, suggested improvements to add a low Reynolds turbulence model if higher accuracy is necessary as well as coupling with thermal stresses to capture the buckling of the strip itself.
Author Response File: Author Response.pdf
Round 3
Reviewer 3 Report
I accept the paper after modifications.
