Experimental and Simulation Analysis of Effects of Laser Bending on Microstructures Applied to Advanced Metallic Alloys

Round 1

Reviewer 1 Report

The manuscript "Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys" has been reviewed.

It deals with experiments and modelling of laser beam forming technology applied on steel and aluminum alloy. The work is interesting despite not new. The novelty, as the main goal, must be more explicit and better highlighted in abstract, introduction and conclusions.

It can be reconsidered after the following major revisions:

INTRODUCTION

Bibliography is not up to date. Please add more recent papers about laser effects on the microstructure and the mechanical properties. The article "Mechanical behavior of Nd:YAG laser welded aluminum alloys" (10.1016/j.prostr.2020.10.017) must be added to the bibliography.

Please check reference format (not apex!). 

Line 41 [2-9]: 8 references one shot is unacceptable. Please Split out!

Line 43 [10-16]: 7 references one shot is unacceptable. Please Split out!

Line 47: " a wide range... have been", change with has been.

Fig. 2, 4 and 5. Please increase readibility.

Line 180: pearlite is not a phase but a mix of two phases (ferrite and cementite).

Line 211: too many spaces.

Par. Stress analysis. It is not clear if the analysis is based on high-precision peaks (increased resolution of the goniometer to 0.005° 2T) or simply a zoom of the diffraction patterns.

Furthermore a peak shift can be ascribed to strain, and successively converted in equivalent stress. Please explain better and add considerations about it!

Line 243. It seems that stresses are extimated (modelling?) or calculated (experimental). Please explain better.

Line 247. For AISI 304 0.5 GPa??? 3 times than RP0,2??? Are your Sure? Please check!

Line 284. Change from compressive to tensile stress means bending on the opposite side? Please clarify this aspect.

REFERENCES (ALL) are not in compliance with the journal requirements. Please follow strictly author's instructions.

Author Response

Revised manuscript “Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys”, submitted to Metals.

The authors thank the valuable comments of the reviewer. The changes in the revised version of this article, which were made according to the reviewer’s comments, are highlighted in red in the manuscript.

Reviewer #1:

The manuscript "Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys" has been reviewed.

It deals with experiments and modelling of laser beam forming technology applied on steel and aluminum alloy. The work is interesting despite not new. The novelty, as the main goal, must be more explicit and better highlighted in abstract, introduction and conclusions.

Authors’ answer: Our main original contribution is the correlation of simulation and experimental results of bending angle together with temperature and microstructure profiles along the thickness of the metal sheets. This point is included in abstract, introduction and conclusions.

It can be reconsidered after the following major revisions:

INTRODUCTION

Bibliography is not up to date. Please add more recent papers about laser effects on the microstructure and the mechanical properties. The article "Mechanical behavior of Nd:YAG laser welded aluminum alloys" (10.1016/j.prostr.2020.10.017) must be added to the bibliography.

Authors’ answer: A wide and deep literature review was performed to elaborate the manuscript. Indeed, more than 80% of the works cited in the introduction were published after 2011. Although the referred paper is not 100 % within the focus of our manuscript, i.e., LBF for bending, it was included in the introduction as part of the works that deal with laser treatments on Al alloys.

Please check reference format (not apex!).

Authors’ answer: Reference format was changed to fit the requirements of the Journal.

Line 41 [2-9]: 8 references one shot is unacceptable. Please Split out!

Authors’ answer: The corresponding phrase and references were changed to works that deal with LBF bending only.

Line 43 [10-16]: 7 references one shot is unacceptable. Please Split out!

Authors’ answer: The corresponding phrase and references were changed to works that deal with LBF on AISI304 only.

Line 47: " a wide range... have been", change with has been.

Authors’ answer: Corrections were done.

Fig. 2, 4 and 5. Please increase readibility.

Authors’ answer: Text size was increased in Figures 2, 4 and 5.

Line 180: pearlite is not a phase but a mix of two phases (ferrite and cementite).

Authors’ answer: “phases” has been replaced by “constituents”.

Line 211: too many spaces.

Par. Stress analysis. It is not clear if the analysis is based on high-precision peaks (increased resolution of the goniometer to 0.005° 2T) or simply a zoom of the diffraction patterns.

Authors’ answer: Resolution of peaks measurement was 0.02° and fitted profile 0.01°, whereas the peak shifts in all the samples were found to be greater than 0.06°.

Furthermore a peak shift can be ascribed to strain, and successively converted in equivalent stress. Please explain better and add considerations about it!

Authors’ answer: The following text was included in order to clarify this point: “The stresses developed in the bending area were estimated on the base of XRD peak’s shifts using Hook’s law and Reuss model. The former correlates the deformation of the interatomic spacing with the stress trough the Young’s modulus and the Poisson ratio, while the latter assumes constant stress in all grains of the polycrystal.”

Line 243. It seems that stresses are extimated (modelling?) or calculated (experimental). Please explain better.

Authors’ answer: The following text was included in order to clarify this point: “The stresses developed in the bending area were estimated on the base of XRD peak’s shifts using Hook’s law and Reuss model. The former correlates the deformation of the interatomic spacing with the stress trough the Young’s modulus and the Poisson ratio, while the latter assumes constant stress in all grains of the polycrystal.”

Line 247. For AISI 304 0.5 GPa??? 3 times than RP0,2??? Are your Sure? Please check!

Authors’ answer: Yes, we are sure, please pay attention that stress values of Table 4 do not correspond to residual stresses. The following text was included in order to clarify this point: “These stresses are estimated with respect to the initial state of the samples, i.e., before the LBF treatment, and therefore cannot be interpreted as residual stresses.”

Line 284. Change from compressive to tensile stress means bending on the opposite side? Please clarify this aspect.

Authors’ answer: No, since stresses estimated due to XRD peak’s shifts are representative of a local volume in the micro range, and do not represent the macro stress of the sheet, which indeed is responsible for the bending direction. The following text was included in order to clarify this point: “It is worth to note that these stresses are representative of volume in the micro range, and do not represent the macro stress of the sheet, which indeed is responsible for the bending direction.”

REFERENCES (ALL) are not in compliance with the journal requirements. Please follow strictly author's instructions.

Authors’ answer: Reference format was changed to fit the requirements of the Journal.

Author Response File: Author Response.pdf

Reviewer 2 Report

Evaluation of the work "Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys"

“specific applications” please provide details which one !

“To this…. (XRD).” Is repeated in abstract …so no need to repeat it couples of time in the same paper

You indicate some of this research was extensively studied but you put down only 19 references..so I suggest to have a compressive introduction

The references should be inserted as per journal style .

Please be consistent with citation style

Please numerate the section accordingly as now is difficult to follow

Not clear details about boundary condition of the numerical model

The microstructure characterization is rather crude in this work, cause only by optical microscopy is not possible to obtain much information

As there is no evidence clear in this work about “be attributed to grain growth” it will be good to put a citation

Where are details of simulated bending angle ???“simulations results”

The conclusions are very brief and do not shows exactly the achievements of this work

In the references, it is required to indicate the title of the works  

Author Response

Revised manuscript “Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys”, submitted to Metals.

The authors thank the valuable comments of the reviewer. The changes in the revised version of this article, which were made according to the reviewer’s comments, are highlighted in red in the manuscript.

Reviewer #2:

Evaluation of the work "Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys"

“specific applications” please provide details which one !

Authors’ answer: Some industries potentially interested in LBF are detailed.

“To this…. (XRD).” Is repeated in abstract …so no need to repeat it couples of time in the same paper

Authors’ answer: The definition of the abbreviation XRD was removed from introduction.

You indicate some of this research was extensively studied but you put down only 19 references..so I suggest to have a compressive introduction

Authors’ answer: The corresponding phrases and references were changed to works that deal with specific areas and applications of LBF for bending.

The references should be inserted as per journal style. Please be consistent with citation style.

Authors’ answer: Reference format was changed to fit the requirements of the Journal.

Please numerate the section accordingly as now is difficult to follow.

Authors’ answer: Sections of the manuscript were numerated as 1, 2, 3, etc. Subsections were numerated as 1.1, 2.2, 3.1, etc.

Not clear details about boundary condition of the numerical model

Authors’ answer: A detailed description of the model (including governing equations, boundary conditions, etc.) has been reported in references 3 and 9 and, therefore, it has not been included in the present work.

The microstructure characterization is rather crude in this work, cause only by optical microscopy is not possible to obtain much information.

Authors’ answer: Microstructure was characterized by standard technics of metallographic preparation for optical inspection, glow discharge optical emission spectroscopy (GDOES) for chemical analysis, and X-ray diffraction (XRD) for phase identification. All the corresponding results were analyzed in the results section and integrated in the discussion section. Further analyses such as EBSD cloud not be performed, but is considered for future investigations on grain growth.

As there is no evidence clear in this work about “be attributed to grain growth” it will be good to put a citation

Authors’ answer: The following references were included to clarify this point.

• Suárez, S.; Ramos-Moore, E.; Mücklich, F. A high temperature X-ray diffraction study of the influence of MWCNTs on the thermal expansion of MWCNT/Ni composites. Carbon N. Y. 2013, 51, 404–409, doi:10.1016/j.carbon.2012.09.002.
• Suárez, S.; Ramos-Moore, E.; Lechthaler, B.; Mücklich, F. Grain growth analysis of multiwalled carbon nanotube-reinforced bulk Ni composites. Carbon N. Y. 2014, 70, doi:10.1016/j.carbon.2013.12.089.

Where are details of simulated bending angle ???“simulations results”

Authors’ answer: The bending angle prediction was the main focus of previous works by the authors and, therefore, details of its computation are cited and not fully provided in this work.

The conclusions are very brief and do not shows exactly the achievements of this work

Our main original contribution is the correlation of simulation and experimental results of bending angle together with temperature and microstructure profiles along the thickness of the metal sheets. This point is included in abstract, introduction and conclusions.

In the references, it is required to indicate the title of the works 

Authors’ answer: Reference format was changed to fit the requirements of the Journal.

In addition, the use of the English language and style were revised throughout the manuscript.

Authors’ answer: English revision was performed using advanced grammar tools.

Author Response File: Author Response.pdf

Reviewer 3 Report

The problem raised in the article is urgent due to the need to get a complete picture of how LBF affects the properties of two advanced materials: IF-steel and aluminium alloy AA6013. The studies were carried out against regarding the reference material: AISI 304 stainless steel. There are the following comments:

1.    Sheets of the supplied materials had different initial thicknesses 1.0 mm, 0.7 mm and 1.6 mm.Did this affect the properties of materials after Laser Beam Forming? 
   Figure 3 should indicate the direction of rolling.
2.  How the LBF treatment influenced on the morphology and parameters of the microstructure? How much has the grain size grown? Has the morphology of the structure changed?
3.  Describe the Reuss method in more detail. what formulas were used for this calculation?
4.  How the Scanning velocity was chosen? Why the samples were scanned at a speed of 5 mm/s and 10 mm/s?
5.  Please, comment table 4.

Author Response

Revised manuscript “Experimental and Simulation Analysis of Effects of Laser Beam Forming on Microstructure Applied to Advanced Metallic Alloys”, submitted to Metals.

The authors thank the valuable comments of the reviewer. The changes in the revised version of this article, which were made according to the reviewer’s comments, are highlighted in red in the manuscript.

Reviewer #3:

The problem raised in the article is urgent due to the need to get a complete picture of how LBF affects the properties of two advanced materials: IF-steel and aluminium alloy AA6013. The studies were carried out against regarding the reference material: AISI 304 stainless steel. There are the following comments:

1. Sheets of the supplied materials had different initial thicknesses 1.0 mm, 0.7 mm and 1.6 mm. Did this affect the properties of materials after Laser Beam Forming?

Figure 3 should indicate the direction of rolling.

Authors’ answer: The thickness does not directly affect the material properties after LBF; they are mainly influenced by the change in microstructure which depends on the energy input during the process.

On the other hand, the rolling direction was not indicated since, according to [3] in which the planar anisotropy degree was assessed with samples cut in three different orientations (0º, 45º and 90º) with respect to the rolling direction, no apparent influence of the sample direction was observed on the resulting bending angle for the three studied materials. Therefore, the sample orientation was found to not have a relevant role in this process.

2. How the LBF treatment influenced on the morphology and parameters of the microstructure? How much has the grain size grown? Has the morphology of the structure changed?

Authors’ answer: The treatment induces mainly grain growth and melting in the case of high surface temperatures. This was qualitatively concluded and therefore further studies using EBSD will be devoted to quantify and better describe the grain growth processes. Surface morphology of the affected areas was modified after melting in the case of the IF sample only. As shown in Figure 4, no phase transitions of the main matrices were observed after the LBF treatments.

3. Describe the Reuss method in more detail. what formulas were used for this calculation?

Authors’ answer: The following text was included in order to clarify this point: “The stresses developed in the bending area were estimated on the base of XRD peak’s shifts using Hook’s law and Reuss model. The former correlates the deformation of the interatomic spacing with the stress trough the Young’s modulus and the Poisson ratio, while the latter assumes constant stress in all grains of the polycrystal.”

4. How the Scanning velocity was chosen? Why the samples were scanned at a speed of 5 mm/s and 10 mm/s?

Authors’ answer: The laser operating parameters were chosen in such a way as to provide enough input energy to effectively bend the sheet after a few laser beam passes. The window of operating parameters for the laser beam given by 100-200 W of power and 5-10 mm/s of scanning velocity was appropriate to that end.

5. Please, comment table 4.

Authors’ answer: New text was included in order to clarify and highlight the results of Table 4.

In addition, the use of the English language and style were revised throughout the manuscript.

Authors’ answer: English revision was performed using advanced grammar tools.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Accept as it is

Reviewer 2 Report

Thank you