Improving the Surface Properties of an API 5L Grade B Pipeline Steel by Applying the Boriding Process. Part I: Kinetics and Layer Characterization

Round 1

Reviewer 1 Report

1. When establishing the dynamic curve of the boriding process, only 3 experimental points were selected for boriding time. Using this regression analysis, the number of experimental points was a little small, at least 5 points.

2. Figure 3 shows the morphology of the boriding layer, and the B element surface distribution analysis is recommended, aiming to prove that the boriding layer is composed of the Fe2B phase.

3. It is recommended to further treat Figure 9 by placing the XRD curve at different times of the same boriding temperature into one graph. Because, Figure 9 is not clear, can not compare.

4. In the "surface performance" statement in the first conclusion, the proposal is clearly stated as "The Hardness and the elastic modulus".

Author Response

Reviewer 1

1. When establishing the dynamic curve of the boriding process, only 3 experimental points were selected for boriding time. Using this regression analysis, the number of experimental points was a little small, at least 5 points.
2. Authors consider that the reviewer refers to Fig 6 & 7. It means that the reviewer recommends including in experiment two additional treatment times. Having more data points can give more accurate information about the changes in the layer thickness histogram. However, Fig. 6 & 7 only pretend to illustrate how the mean, standard deviation and histogram shape tend to change over time. Besides, adding two more points in the experiment will not add significant information that provokes modifying the conclusions of the research work. So, the authors disagree with carrying out arduous experimental work that is of little value to the paper.
3. Figure 3 shows the morphology of the boriding layer, and the B element surface distribution analysis is recommended, aiming to prove that the boriding layer is composed of the Fe2B phase.
4. Authors agree with the reviewer in which the B element surface distribution analysis could prove the composition of the boride layer, however, the XRD analysis showed in section 3.4, provide enough information about the chemical composition of the layers and its crystalline structure.
5. It is recommended to further treat Figure 9 by placing the XRD curve at different times of the same boriding temperature into one graph. Because, Figure 9 is not clear, cannot compare.
6. Authors have updated the Figure 9. Now is divided into 4 figures to facilitate the visibility.
7. In the "surface performance" statement in the first conclusion, the proposal is clearly stated as "The Hardness and the elastic modulus".
8. As suggested by the reviewer, the first conclusion was modified as: “It is possible to enhance the surface properties such as hardness and young modulus of a pipeline steel API 5L Grade B by a thermochemical process called packed powder boriding”.

ALL THE SENTENCES ADDED IN THE MANUSCRIPT ARE IN RED TO FACILITATE THE REVIEW

Author Response File: Author Response.docx

Reviewer 2 Report

Reviewer Comment

Manuscript Number: coatings-2150608

Journal: coatings

Dear Editor,

This paper deals the “Improving the surface properties of an API 5L grade B pipeline 2 steel by applying the boriding process. Part I: Kinetics and 3 layer characterization.

The following is a report on the above manuscript, I recommend reconsideration of the manuscript after minor Revision.

1.      The scientific content of the manuscript is good.

2.      The title must reform.

3.      Please revise "Keywords".

4.      the novelty of the work has not been demonstrated appropriately in the introduction section.

5.      In the introduction section, the number of recent references (2016 – 2021) is limited. The following references should be included in the manuscript.

-A. Ejbouh, A. Ech-chebab, M. Galai, R. Lachhab, H. Benqlilou, M. Ebn Touhami, Effects of fly ash and simulation of the natural hot and dry climate of the Moroccan desert region on the durability of prestressed concrete cylinder pipes, J. Pipeline Syst. Eng. Pract. 13 (4) (2022) 04022029.

-A. Ech-chebab, A. Ejbouh, M. Galai, S. Hassi, T. Belhaj, M.E. Touhami, The individual and combined effect of olive stone biomass ash with coal fly ash on the durability of water treatment tank concrete exposed to ferric chloride, Chem. Afr. (2022) 1–18.

-A. Ech-chebab, A. Ejbouh, M. Galai, S. Hassi, K. Berrami, M.E. Touhami, Assessing the fly ash effect on the durability of reinforced concrete of water treatment tanks exposed to coagulating ferric chloride by an electrochemical process, J. Bio- Tribo Corros. 7 (2) (2021) 1–17.

-A. Ejbouh, A. Ech-chebab, M. Galai, S. Hassi, H. Benqlilou, M.E. Touhami, Calcined clay process for durability performance of concrete pipe in simulated semi-arid area in Morocco, Mater. Today. Proc. (2022).

-Galai, Mouhsine, Mohamed Rbaa, Moussa Ouakki, Lei Guo, Khadija Dahmani, Khalid Nouneh, Samir Briche, Brahim Lakhrissi, Nadia Dkhireche, and Mohamed Ebn Touhami. "Effect of alkyl group position on adsorption behavior and corrosion inhibition of new naphthol based on 8-hydroxyquinoline: Electrochemical, surface, quantum calculations and dynamic simulations." Journal of Molecular Liquids 335 (2021): 116552.

-Dahmani, K., M. Galai, A. Elhasnaoui, B. Temmar, A. El Hessni, and M. Cherkaoui. "Corrosion resistance of electrochemical copper coating realized in the presence of essential oils." Der PharmaChemica 7 (2015): 566.

-Ouakki, Moussa, Mouhsine Galai, Zakaria Benzekri, Zakia Aribou, Elhachmia Ech-chihbi, Lei Guo, Khadija Dahmani et al. "A detailed investigation on the corrosion inhibition effect of by newly synthesized pyran derivative on mild steel in 1.0 M HCl: Experimental, surface morphological (SEM-EDS, DRX& AFM) and computational analysis (DFT & MD simulation)." Journal of Molecular Liquids 344 (2021): 117777.

6.      RESULTS and DISCUSSION section. The authors gave discussion, but the discussion was not adequate and was not compared with similar discussion and results that were published by other authors.

7.      All figure captions should provide with all the necessary information. The author should present the figures with high resolution

Author Response

Reviewer 2

Dear Editor,

This paper deals the “Improving the surface properties of an API 5L grade B pipeline steel by applying the boriding process. Part I: Kinetics and layer characterization.

The following is a report on the above manuscript, I recommend reconsideration of the manuscript after minor Revision.

1. The scientific content of the manuscript is good.
2. The title must reform.
3. Authors consider that the title shows the information displayed in this manuscript
4. Please revise "Keywords".
5. Authors consider that the keywords included in the paper are enough and correct because they capture the essence of the research.
6. the novelty of the work has not been demonstrated appropriately in the introduction section.
7. To emphasize the novelty of the research work, the authors add the following paragraph in the introduction section:

“Typically, API 5L series or equivalent materials are steels that contain Cu and Cr to enhance the corrosion resistance; P and S as impurities; and Si and Mn that tend to increase the hardness, yield strength, and ultimate tensile strength [¹³]. Therefore, studying the kinetics and growth of the boride layers in steels under the interaction of these alloy elements is a novelty that could lead to an interesting industrial application.”

5. In the introduction section, the number of recent references (2016 – 2021) is limited. The following references should be included in the manuscript.

-A. Ejbouh, A. Ech-chebab, M. Galai, R. Lachhab, H. Benqlilou, M. Ebn Touhami, Effects of fly ash and simulation of the natural hot and dry climate of the Moroccan desert region on the durability of prestressed concrete cylinder pipes, J. Pipeline Syst. Eng. Pract. 13 (4) (2022) 04022029.

-A. Ech-chebab, A. Ejbouh, M. Galai, S. Hassi, T. Belhaj, M.E. Touhami, The individual and combined effect of olive stone biomass ash with coal fly ash on the durability of water treatment tank concrete exposed to ferric chloride, Chem. Afr. (2022) 1–18.

-A. Ech-chebab, A. Ejbouh, M. Galai, S. Hassi, K. Berrami, M.E. Touhami, Assessing the fly ash effect on the durability of reinforced concrete of water treatment tanks exposed to coagulating ferric chloride by an electrochemical process, J. Bio- Tribo Corros. 7 (2) (2021) 1–17.

-A. Ejbouh, A. Ech-chebab, M. Galai, S. Hassi, H. Benqlilou, M.E. Touhami, Calcined clay process for durability performance of concrete pipe in simulated semi-arid area in Morocco, Mater. Today. Proc. (2022).

-Galai, Mouhsine, Mohamed Rbaa, Moussa Ouakki, Lei Guo, Khadija Dahmani, Khalid Nouneh, Samir Briche, Brahim Lakhrissi, Nadia Dkhireche, and Mohamed Ebn Touhami. "Effect of alkyl group position on adsorption behavior and corrosion inhibition of new naphthol based on 8-hydroxyquinoline: Electrochemical, surface, quantum calculations and dynamic simulations." Journal of Molecular Liquids 335 (2021): 116552.

-Dahmani, K., M. Galai, A. Elhasnaoui, B. Temmar, A. El Hessni, and M. Cherkaoui. "Corrosion resistance of electrochemical copper coating realized in the presence of essential oils." Der PharmaChemica 7 (2015): 566.

-Ouakki, Moussa, Mouhsine Galai, Zakaria Benzekri, Zakia Aribou, Elhachmia Ech-chihbi, Lei Guo, Khadija Dahmani et al. "A detailed investigation on the corrosion inhibition effect of by newly synthesized pyran derivative on mild steel in 1.0 M HCl: Experimental, surface morphological (SEM-EDS, DRX& AFM) and computational analysis (DFT & MD simulation)." Journal of Molecular Liquids 344 (2021): 117777.

1. The authors agree with these suggestions. The following sentences were included that refers to the papers recommended:

“Steel pipelines can be corroded externally or internally []. Even if the transmitted fluid contains inhibitors [].”

6. RESULTS and DISCUSSION section. The authors gave discussion, but the discussion was not adequate and was not compared with similar discussion and results that were published by other authors.
7. Recently, the authors upload to Coatings Journal (MDPI) the second part of the present research work and it is titled: “Improving the surface properties of an API 5L grade B pipeline steel by applying the boriding process. Part II: On the changes in the mechanical properties”. This paper will include one section with a deeper discussion of all the research work (Part I and Part II). However, the authors agree to include a discussion that compares results from other research works. The following subsection is added to the manuscript:

“3.7 Analysis of the results

First of all, one important result is that the boride layer formed over API 5L grade B steel is only composed of Fe₂B. This result is typically unusual for carbon steels and ductile iron, because these materials tend to facilitate the formation of a biphasic layer (Fe₂B + FeB). Due to the mechanical characteristics of the Fe₂B layer, the formation of this layer is more desirable because it is less brittle [53, 54, 55]. Boron reacts with Fe₂B at the B-Fe₂B interface, producing FeB depending on the alloy elements of the substrate, the temperature, and the treatment time [²⁸]. Fe₂B is much more stable than FeB, and the growth of Fe₂B takes place earlier. Therefore, it seems that the formation of Fe₂B is ideal to protect the oil and gas pipeline composed of API 5L grade B steel because it does not require a large amount of activation energy, it is not too brittle, and it increases the hardness and wear resistance.

In other research works [28,25], the mean value of layer thickness is used to model layer growth. This research shows that the mode could reduce the error obtained when we model the growing layer. This point could be helpful in developing more reliable contour diagrams.

Due to the changes provoked in the substrate grain size, it is necessary to consider studying the changes in the mechanical properties. However, this point will be studied and presented later, in the second part of this research work.”

7. All figure captions should provide with all the necessary information. The author should present the figures with high resolution.
8. The authors agree with the comments. In the new version of the manuscript, the resolution of the figure is improved

ALL THE SENTENCES ADDED IN THE MANUSCRIPT ARE IN RED TO FACILITATE THE REVIEW

Author Response File: Author Response.docx

Reviewer 3 Report

·       The current work uses a thermochemical method known as packed powder boriding to improve the surface qualities of a pipeline made of steel with an API 5L Grade B designation. The work is good but still needs some improvement to be published. Here, major comments need to be answered and resolved in the manuscript.

1)      The abstract is too general, so readers cannot grasp the content quickly. In the "abstract " section, indicating specific/numerical values for the properties would be more informative.

2)      Figure 1 Boriding process flow chart, should be represented with readable font

3)      The authors did not mention the coating particles' B4C specifications and size, TEM, .etc.. please provide the manuscript with more details about the main component in the current work.

4)      Line 141, “[:27, 28].” Wrong citation method.

5)      Figure 3 shows  “ Cross section of the samples exposed to the different treatment conditions, “ which method is used to make the section in the processed sample. , also what is the reference used in this process to show the coating layer

6)      Figure 4. need a high-resolution figure instead

7)      Tables 14 and 15  missed the unit of the grain size

8)      The authors must provide the manuscript with Optical microscopy images of at least 50 um magnification for each case before and after coating.

9)      The hardness behavior should be graphically represented in the manuscript

Author Response

Reviewer 3

Comments and Suggestions for Authors

• The current work uses a thermochemical method known as packed powder boriding to improve the surface qualities of a pipeline made of steel with an API 5L Grade B designation. The work is good but still needs some improvement to be published. Here, major comments need to be answered and resolved in the manuscript.

1)      The abstract is too general, so readers cannot grasp the content quickly. In the "abstract " section, indicating specific/numerical values for the properties would be more informative.

The authors agree with the reviewer; some results were added to the abstract to provide more information to the readers.

2)      Figure 1 Boriding process flow chart, should be represented with readable font

According to the reviewer suggestion, Figure 1 was improved

3)      The authors did not mention the coating particles' B4C specifications and size, TEM, .etc.. please provide the manuscript with more details about the main component in the current work.

According to the reviewer suggestion, new information was added to the experimental procedure section as follows: “After cleaning, the samples were introduced into a stainless-steel crucible with the boriding agent containing 5% wt. of B4C as boron donor, 5% wt. of KBF4 as activator, and 90% wt. of SiC as diluent, with a powder size of 50 ?m, Hef-Durferrit (DURFERRIT, GmbH, Mannheim, Germany

4)      Line 141, “[:27, 28].” Wrong citation method.

Authors agree in correcting this issue.

5)      Figure 3 shows  “ Cross section of the samples exposed to the different treatment conditions, “ which method is used to make the section in the processed sample. , also what is the reference used in this process to show the coating layer

According to the reviewer’s suggestion, new information was added to the manuscript to clarify the used method to make the section in the processed samples, as follow:

“One face of each square samples was processed by metallographic process to obtain a cross section for layers examination”

Additionally, Figure 3 was improved to show the reference used for the layers thickness measurement.

6)      Figure 4. need a high-resolution figure instead

Figure 4 was improved in the manuscript

7)      Tables 14 and 15 missed the unit of the grain size

In these tables the grain size is in ASTM number (not dimensional number) conforming the standard ASTM E112 “Standard Test Methods for Determining Average Grain Size”

8)      The authors must provide the manuscript with Optical microscopy images of at least 50 um magnification for each case before and after coating.

The authors are not sure what the reviewer mean when says “50 µm magnification”. Reviewers Probably refers to 50X magnification. In that case, the authors want to comment that the micrographs were taken to 20X magnification because the boride layers formed to 1000 ºC for 6h were to large so, they don't fit in an image taken at 50X

9)      The hardness behavior should be graphically represented in the manuscript

A new image was added to show graphically the behavior of the hardness and elastic modulus of the boride layers (Figure 10).

ALL THE SENTENCES ADDED IN THE MANUSCRIPT ARE IN RED TO FACILITATE THE REVIEW

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

The authors have made the necessary changes, and I recommend the manuscript for publication