The Microstructure and Property of a Titanium-Carbon Steel Clad Plate Prepared Using Explosive Welding
Round 1
Reviewer 1 Report
The writing of English should be improved, I suggest the authors get editing help from someone with full professional proficiency in English. Meanwhile, some spelling mistakes should be carefully checked. For example, Vickers; (Line 234) Ge70
Welding window, impact angle, and explosion ratio must be calculated and reported.
Tables 1 and 2 should be merged.
Figure 2a has no special scientific value and can be omitted.
Possible intermetallic compounds in the interface should be investigated and compared with other references.
The number of samples tested for tensile and shear strength and the tolerance value of the results must be given.
In Figure 7 a sample schematic and test method should be provided.
Line 203 “shearing strength (τb) was 175 MPa and 200 MPa“, What is the condition of shear strength 175 and 200?
Line 215- In the text, 300 micrometers should be given instead of 300 millimeters?
Is the tensile test sample scale correct in Figure 8a? Sample length should be written in millimeters.
In Figure 8b, column 1 is for tensile strength and column 2 is for yield strength. (Incorrectly introduced in the diagram)
Table 3 Ecorr units should be mV (millivolts).
In Conclusions 5, the absolute value of Ecorr value should be considered and expressed.
The literature review is not sufficient and authors must review and cite more papers in the field and especially newly published ones. Doing this, reviewing the following refs could be helpful:
[a] Materials Research, 20, 2017, 291-302
[b] International Journal of Pressure Vessels and Piping, 188, 2020, 104216.
Author Response
Thank you for your advice. I have learned a lot form them. Now, I have revised the paper, including the English writing and spelling mistake. Also, I have revised according to other review advice:
The writing of English should be improved, I suggest the authors get editing help from someone with full professional proficiency in English. Meanwhile, some spelling mistakes should be carefully checked. For example, Vickers; (Line 234) Ge70
Answer:I have revised the paper with the help of the person with professional proficiency in English. And I also check and correct carefully spelling mistakes in my paper.
Welding window, impact angle, and explosion ratio must be calculated and reported.
Answer:I have supplied these data in the paper.
Tables 1 and 2 should be merged.
Answer: I have Merged the table1 and table2
Figure 2a has no special scientific value and can be omitted.
Answer:Figure 2a shows the size and appearance of the clad plate. I want to keep Figure 2a.
Possible intermetallic compounds in the interface should be investigated and compared with other references.
Answer:According to the references [7-11,14]，the intermetallics could be FeTi or Fe2Ti, but in this paper, the elements maps show that It is almost Fe in the molted block, and a few Ti distribute uniformly in the block. The result is different with the references[7-11,14]. It could be related with the parameters of explosive welding. And it will be investigated in my subsequent future research.
The number of samples tested for tensile and shear strength and the tolerance value of the results must be given.
Answer: I added the number of specimens in the paper (in line 98-99). The number and tolerance value of the samples for tensile and shearing test would meet the requirement of ASTM B 898 standard [15]. I showed them in the paper (line 97-99).
In Figure 7 a sample schematic and test method should be provided.
Line 203 “shearing strength (τb) was 175 MPa and 200 MPa“, What is the condition of shear strength 175 and 200?
Answer:In ASTM B 898 standard [15], the requirement of sample Shearing test were carried out at room temperature. The shearing speed was 0.2 mm/min. I have added them in the paper (line 98-101). The shearing strength(175 MPa and 200 MPa) of the clad plate is higher than that for the requirement of ASTM B898 specification (τb≥137.9 MPa is acceptable). I showed them in line 207-210.
Line 215- In the text, 300 micrometers should be given instead of 300 millimeters?
Answer: 300 micrometers have be given in stead of 300 millimeters in the paper (in line 221)
Is the tensile test sample scale correct in Figure 8a? Sample length should be written in millimeters .
Answer: The length of tensile test sample scale have be written in millimeters (line 250).
In Figure 8b, column 1 is for tensile strength and column 2 is for yield strength. (Incorrectly introduced in the diagram)
Answer: I have revised the Figure 8 and b
Table 3 Ecorr units should be mV (millivolts).
Answer:I have revised the Ecorr units (line 256)
In Conclusions 5, the absolute value of Ecorr value should be considered and expressed.
Answer:I have revised and used the absolute value of Ecorr
The literature review is not sufficient and authors must review and cite more papers in the field and especially newly published ones. Doing this, reviewing the following refs could be helpful:
[a] Materials Research, 20, 2017, 291-302
[b] International Journal of Pressure Vessels and Piping, 188, 2020, 104216.
Answer:I revised and cited tow references(Refs.16-17) in my paper.
Reviewer 2 Report
Please make sure the formatting is right. The text fonts seem to be different from the MDPI template.
I would suggest using the full name SA516 Gr70) for the carbon steel whenever you mention it - also in the abstract, etc. same with the Ti - maybe Ti-Gr1
"Hardness test showed..." make sure you stick to one time...
Quickly name the requirements of ASTM B989 in once sentence
Line 40 - Ref. 9-29 - I feel 1-3 references should be sufficient - 20 References or 66% of all the references in this work seems a bit excessive, ideally use review papers.
I am also not sure I agree with the overall statement - solid state welding is often used to join steel and titanium - explosion welding is most certainly a great methods, but why it is better than diffusion bonding/brazing is for instance not explained.
Here is a review that discusses diffusion bonding and TLP bonding of stainless steels with other materials including titanium (https://doi.org/10.3390/met10050613) - this could for instance be another suitable method. At my institute in Singapore we cannot do explosion welding - there is simply no space - so for us diffusion bonding is the only option.
Line 43 - this is not "low cost" - it can reduce costs yes since it might be cheaper than pure Ti, but it is not "low cost" if I compare this to Al or just carbon steel
1 is a detonator
Fig 2 is great - maybe just place them next to each other to save some space and get them all together on one page.
For how long was the material annealed at 550-650 C? and in what atmosphere?
Try to get Fig 4 on one page - maybe by placing the spot analysis next to the microstructure image. Again the results look great - can just be presented nicer.
Line 180 - "hardness" - look through all this and search for typos and language issues...
Did you experience any deformation of the whole plate? or some bending? Please elaborate.
Figure 8 a and b can also be put next to one another. Is that all from 1 sample or did you do more samples and take an average? What about uncertainties?
Author Response
Reviewer2
Thank you for your advice. I have learned a lot form them. Now, I have revised my paper as follow:
I would suggest using the full name SA516 Gr70) for the carbon steel whenever you mention it - also in the abstract, etc. same with the Ti - maybe Ti-Gr1
Answer: I have revised the name of metals in the paper.
"Hardness test showed..." make sure you stick to one time...
Answer: I have revised the mistakes in line 15
Quickly name the requirements of ASTM B989 in once sentence
Line 40 - Ref. 9-29 - I feel 1-3 references should be sufficient - 20 References or 66% of all the references in this work seems a bit excessive, ideally use review papers.
Answer: I reduced the references. Now only 23 references in my paper.
I am also not sure I agree with the overall statement - solid state welding is often used to join steel and titanium - explosion welding is most certainly a great methods, but why it is better than diffusion bonding/brazing is for instance not explained.
Here is a review that discusses diffusion bonding and TLP bonding of stainless steels with other materials including titanium (https://doi.org/10.3390/met10050613) - this could for instance be another suitable method. At my institute in Singapore we cannot do explosion welding - there is simply no space - so for us diffusion bonding is the only option.
Answer: Comparing with diffusion bonding/brazing methods, explosive welding would avoid the formation of lots of brittle Fe-Ti series intermetallic compounds owing to the restricted solubility between Fe and Ti. These brittle Fe-Ti intermetallic compounds will weaken the joint strength. I added the reason in the paper (line 40-43). And there are some clad materials manufacturing factories in Xi’an, China. They product the clad materials by using explosive welding. I have some Joint cooperation with them. Thus I could do the experiments in the production spot of these factories. If you are interested in explosive welding, Welcome to our university, and experiments or technique communicates are all OK. (My e-mail: [email protected])
Line 43 - this is not "low cost" - it can reduce costs yes since it might be cheaper than pure Ti, but it is not "low cost" if I compare this to Al or just carbon steel
Answer: I replaced the “low cost” by “ reduce costs” in line 46-47.
1 is a detonator
Answer: I revised the Figure 1 caption and main text (line 78-79).
Fig 2 is great - maybe just place them next to each other to save some space and get them all together on one page.
Answer: I revised the Figure 2 (line 130)
For how long was the material annealed at 550-650 C? and in what atmosphere?
Answer: 1hour and in atmosphere. I added the experimental condition in my paper (line 119)
Try to get Fig 4 on one page - maybe by placing the spot analysis next to the microstructure image. Again the results look great - can just be presented nicer.
Answer: I revised Figure 4 (line170-176).
Line 180 - "hardness" - look through all this and search for typos and language issues...
Answer: I revised spelling mistakes (line 183-203).
Did you experience any deformation of the whole plate? or some bending? Please elaborate.
Answer: Yes. After explosive welding, the plate would deform. And the deformation of the plate is related to the thickness of base plate and the height of explosive. The clad plate should be heat treated. After that, flattening should be performed on the clad plate. For example, the clad plate (TC4/304L, thickness: 1/4mm) deformed strongly (Figure below ). Max. the flatness reached to 40mm. After flattening, Max. the flatness was 30mm. However, the plate would be cut to small blocks (100×100mm) before supplied to customer, and flatness had no harmful effect on the application of the clad plate. Also, the titanium carbon steel clad plate in this paper deformed by using explosive welding (Figure 2a in my paper). The clad plate was heat treated and flattened. After that, the flatness of the plate is under 8mm/m. Thus, it meets the application requirement of customer (the pictures shown in the attachment).
Figure TC4/304L clad plate before and after
Figure 8 a and b can also be put next to one another. Is that all from 1 sample or did you do more samples and take an average? What about uncertainties?
Answer: I revised Figure8. The clad plate is the sale product. Thus the tests should be carried out according to the ASTM B 898 standard. In the standard, one sample for tensile test and one for shearing test. If the test results are not acceptable, double samples should be needed. The tests results meet the requirements of the standard. Thus I took one sample for tensile test and one for shearing test.
Author Response File: 
Author Response.pdf
Round 2
Reviewer 1 Report
The revised manuscript is acceptable for publication.
Reviewer 2 Report
Excellent - all issues raised have been addressed - this manuscript can now be accepted for publication.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The paper exhibits an interesting study about the processing of Ti-carbon steel plates by explosive welding. There are some points that must be checked by the authors:
- An extensive English language revision is required, once several words are misspelled, including some physical units. See the annotated manuscript;
- Indicate if the proportion of the elements displayed in Table 1 and 2 are in at% or wt%;
- Page 6 line 157: "... shearing tests are 175 MPa and 200 MPa ...". State clearly what kind of mechanical property it refers to;
- Page 6 line 158: "... requirement of ASTM B898 specification...". Insert the value described in the text. It could be better for the readers;
- Figure 8: The results should be compared with Gr1 and Gr70 samples, in the same way as the electrochemical results;
- I believe that more results are required to support the conclusions made. Thus, EDS chemical mapping, as well as Vickers microhardness and shear mechanical test of the interface, could provide interesting results and strengthen the study.
Comments for author File: Comments.pdf
Author Response
- I have revised the English language problems, such as misspell, physical units and figures according to the annotated manuscript.
- The proportion of the elements in Table1 is wt%, and I have revised in my paper.
- The shearing test was conducted to evaluate the bonding quality of the clad plate. After shearing test, shearing strength (τb) was obtain. I revised and stated the mechanical property in my paper. Also, I revised and inserted the value in the requirement of ASTM B898 specification
- According to ASTM B898 specification, the values of tensile test result are Rp0.2b≥260MPa, Rm≥485MPa, A≥17%. I have inserted the specification requirement in my paper. Thus, the tensile test results might be compared with the specification requirements. I have stated it in my paper. I also supply EDS element mapping and Vickers microhardness tests to support the conclusions in my paper. However the shearing test sample surface was destroyed, the fatigue test of shearing test sample could not be conducted. And I would supply fatigue test of shearing test sample in the future research.
Reviewer 2 Report
- Authors can provide application of these dissimilar joints. Authors have explained about the application of titanium, but this sandwich joint application should be specified
- Authors can share bend test results to further project the soundness of the joints
- What about intermetallics at the interface.
Author Response
Dear reviewer, thank you for your advises. I have revised my paper as follow:
- I have suppliedthe sandwich joint application in Introduction part.
- In ASTM B898 specification, shearing test result was supplied to evaluate the bonding quality of the caldded plate. So I just carried out the shearing test. The clad plate was supplied to the purchaser. I have not enough sample for bending test. But I would carried out the bending test in future research.
- According to the references [7-11,14]，the intermetallicscould be FeTi or Fe2Ti, but in this paper, the elements maps show that It is almost Fe in the molted block, and a few Ti distribute uniformly in the block. Thank you for your advises, it will be investigated in my subsequent future research.
Reviewer 3 Report
The work is devoted to the critical and urgent problem of producing a bimetallic compound of steel and titanium alloy. The manuscript is of high quality, but there are some comments:
1. A proofreading is needed. The authors should carefully review the manuscript's text to improve the English and correct typos, such as in line 44, "After welding, the he microstructure...".
2. The authors should improve the introduction. It would be desirable to see an analysis of current advances in titanium-based bimetallic components production, as well as a detailed description of the problems that need to be solved, including those in this manuscript.
3. In the results, you state that the presence of molten regions does not affect the properties of the sample. Have you evaluated the fatigue behavior of such a clad plate or its impact toughness? Maybe it has been done by other researchers? Probably, the material may behave differently when the loading conditions change.
Author Response
Dear reviewer, thank you for your advises. I have revised my paper as follow:
- I revised carefully mypaper and corrected the misspe
- I have improved the introduction of the paper.
- Base on the production experiences, I state that the noncontinuousmolten does no affect the bonding properties of the sample. Also, some references show the similar results[9-11, 14]. I have add the references in the paper. Thank you for your advises, in the future research, I will investigate the fatigue behavior and impact toughness of the cladded plate.
Reviewer 4 Report
The properties of the Ti-steel material are very promising. However, there are numerous papers already published on the same topic. There are also commercial suppliers of these materials (e.g https://www.samaterials.com/titanium-clad-materials/1442-titanium-clad-carbon-steel.html
or
https://m.made-in-china.com/product/Titanium-Carbon-Steel-Clad-Steel-Sheet-694611242.html). Authors have to declare what is the prime novelty of the reviewed manuscript.
There are also minor language problems, which have to be corrected, e.g. "the he microstructure", "Parallel arrangement were (was) employed for the experiment...", "The cross-sections of specimens were grounded" (ground or grinded, because "grounded" means something completely different).
Author Response
- Recently, the interface microstructure and mechanical properties of titanium clad materials have been investigated by some studies[9-15]. However, until now few works have been carried out on the corrosion resistance of the titanium materials before and after explosive welding. For this purpose, in this paper, corrosion resistance of the cladded material were investigatedand compared with original titanium materials. There is some difference according to the test results.
- Iam sorry for the misspelling. I have corrected the problems.
Round 2
Reviewer 1 Report
The modifications made in the manuscript attended to the earlier issues indicated by this reviewer.
Just pay attention in page 2, change "g/com3" for g/cm3".
I consider the paper suitable for publishing in the Journal.
Author Response
Thank you for your advises. I have revised the "g/com3" to " g/cm3".
Reviewer 4 Report
The paper still contains a lot of mistypes and language problems, even in the newly added part. When we consider that "Metals" is a highly ranked journal, this is not acceptable.
Also the justification for the aim is not sufficient. The corrosion properties of such cladded material will be very similar as of the material on the surface itself, nothing surprising. It is known also in the case of other cladded materials. Such materials are already applied in the industry, so it is nothing new. Even after the added explanation, I see no added value of this paper.
Author Response
Thank you for you advises. I check this paper carefully again, and revised the misspelling. During the explosive welding, the huge impact pressure could effect the substructure of the titanium layer in claded plate. Thus, the Ecorr value of titanium is more negative and icorr is 1 order of magnitude lower than that of the titanium layer of clad plate. But the effect can not be investigated by SEM and EDS. So I will investigate the cladded plate by other method (such TEM) in the future study.
