Influence of Deposition Patterns on Distortion of H13 Steel by Wire-Arc Additive Manufacturing
Round 1
Reviewer 1 Report
Dear Authors,
I have reviewed paper titled "Influence of Deposition Patterns on Distortion of H13 Steel by Wire Arc Additive Manufacturing", which has been sent to Metals journal as a proposal for publishing.
The paper presents important and valuable investigations in the field of the additive manufacturing.My suggestions, which may be helpful for the Authors, are listed below.
General remarks:
- You have presented only 18 references. I propose, to extend this lis, which will provide to increasing the visibility of your work. I recommend to present positions published in 2020 and 2021 - now, you do not have any reference from these years.
- Please support equations with reference.
Introduction:
- I propose to add some information about the usage of the parts produced by WAAM process.
- In traditional welding processes, the paramters have crutial impact on the distortion (e.g. 10.22190/FUME200520044T ). Please discuss the influence of the process parameters on the distortion in WAAM.
Materials and Methods:
- Table 2 - the source of presented values is missing. Analysis (if yes, which method), manufacturer data or standard (if yes, thee number is required) - please add relevant information,
- Table 2 - the content of carbon in both material are much different. Please clarify for potential readers, why this wire has been chosen. What was the aim by using this wire? Why this kind of filler materials are used for substrates? This should be clear for all readers, not only experts in welding engineering.
- Table 3 - the description is required. Why these parameters were used? Have they been chosen during preliminary investigations, previous investigations, from literature of manufacturer requirements?
- Line 98 - which type of thermocouples have you used, K type? Please add relevant information.
Results:
- This part of your work is very strong. The results are clear and easy to understand. I have no suggstions here.
Discussion:
- This part requires modification. I cannot find any scientific discussion with other scientiests. Please compare your results with other papers. Mark the advantages observed in your experiments.
Conclusions:
- Please support your conclusions with values from experiments.
Author Response
Dear Authors,
I have reviewed paper titled "Influence of Deposition Patterns on Distortion of H13 Steel by Wire Arc Additive Manufacturing", which has been sent to Metals journal as a proposal for publishing.
The paper presents important and valuable investigations in the field of the additive manufacturing. My suggestions, which may be helpful for the Authors, are listed below.
General remarks:
- You have presented only 18 references. I propose, to extend this lis, which will provide to increasing the visibility of your work. I recommend to present positions published in 2020 and 2021 - now, you do not have any reference from these years.
√ Thanks for your suggestions. We reviewed and cited some literatures published in 2020 and 2021.
- Please support equations with reference.
√ The equations in 4.2 could be supported by the literature “Ueda, Y., Murakawa, H., Ma, N. Introduction to Welding Mechanics. Welding Deformation and Residual Stress Prevention”, doi:10.1016/b978-0-12-394804-5.00001-3, Page 17-29.
The reference has been cited as [25]. We hope that it might help the manuscript understandable.
Introduction:
- I propose to add some information about the usage of the parts produced by WAAM process.
√ We have added the relevant information as your suggestion in Page 1.
- In traditional welding processes, the parameters have crutial impact on the distortion (e.g. 10.22190/FUME200520044T). Please discuss the influence of the process parameters on the distortion in WAAM.
√ We have reviewed and cited the paper by Jacek Tomków et al. on angular distortion. The influence of process parameters on distortion in WAAM was discussed in Page 2.
Materials and Methods:
- Table 2 - the source of presented values is missing. Analysis (if yes, which method), manufacturer data or standard (if yes, the number is required) - please add relevant information,
√ The source of the H13 wire and Q345 substrate are both commercially available. The values listed in Table 2 can be obtained in the lists provided by factory. Relevant information was added in Page 3.
- Table 2 - the content of carbon in both materials are much different. Please clarify for potential readers, why this wire has been chosen. What was the aim by using this wire? Why this kind of filler materials are used for substrates? This should be clear for all readers, not only experts in welding engineering.
√ The usage of the H13 part produced by WAAM technology was introduced according to your advice in Page 1, which was highlighted in red.
There are two main considerations for choosing Q345 as substrate.
(1) Reduce production costs. In engineering application, the functional component produced by WAAM are the deposited parts and the substrate should be removed after deposition. The cost of H13 plate is about 7 times higher than Q345 plate.
(2) H13 weld bead can be well formed on Q345 plates. Except for Q345 and H13 plates, we also tried Q235 and 321 stainless steel. We found severe welding spattering and discontinuous weld bead when Q235 and 321 stainless steel were used. While the weld formation on Q345 was similar with that on H13. So Q345 was chosen as the substrate.
A sentence has been added in Page 3.
- Table 3 - the description is required. Why these parameters were used? Have they been chosen during preliminary investigations, previous investigations, from literature of manufacturer requirements?
√ The parameters used in this study were chosen from preliminary investigations. Considering the weld formation, production efficiency and defects in the parts, these parameters were finally selected.
A sentence was added in Page 3.
- Line 98 - which type of thermocouples have you used, K type? Please add relevant information.
√ Type-K thermocouples with a diameter of 0.5 mm were used in this study. Relevant information was added in Line 105.
Results:
- This part of your work is very strong. The results are clear and easy to understand. I have no suggestions here.
√ Many thanks for the encouraging comments from reviewer.
Discussion:
- This part requires modification. I cannot find any scientific discussion with other scientists. Please compare your results with other papers. Mark the advantages observed in your experiments.
√ Thanks for modification suggestions. We have modified this part as your advice.
Discussion from other scientists and comparison with other papers were added in Page12. Advantages observed in our experiments were added in Page 9.
Conclusions:
- Please support your conclusions with values from experiments.
√ Thanks for your suggestion. We have modified the conclusion as your advice.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper reports the analysis of distortion on a WAAM'ed H13 steel. This represents a quite interesting topic; however, given the structure of the paper it could be referring to whichever kind of metal alloy rather than to a tool steel.
Actually the material is introduced in few lines (88 to 94). After that there is no recall of any characteristic related to the material, neither mechanical nor microstructural.
The paper is therefore judged to be not relevant to a journal like "Metals" but to a more specific journal devoted to materials processing.
Author Response
The paper reports the analysis of distortion on a WAAM'ed H13 steel. This represents a quite interesting topic; however, given the structure of the paper it could be referring to whichever kind of metal alloy rather than to a tool steel.
Actually the material is introduced in few lines (88 to 94). After that there is no recall of any characteristic related to the material, neither mechanical nor microstructural.
The paper is therefore judged to be not relevant to a journal like "Metals" but to a more specific journal devoted to materials processing.
√ Dear professor, thanks for your comments on our study. This study focused on the distortion of H13 steel during the WAAM process. There is a great temperature gradient in the process of WAAM, which makes the materials produce different thermal expansion and so that different strain. During the heating process, the thermal strain evolved in the materials:
ε=α·ΔT
Take aluminum and steel as examples, the coefficient of thermal expansion for aluminum and steel are 2.0×105 ℃-1 and 1.3×105 ℃-1 respectively, and melting point are 650 ℃ and 1435 ℃ respectively. There will be a greater thermal strain in steel than that in aluminum, so that larger distortion in steel.
A sentence was added in Page 9.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper presents results about the distortion in WAAM of H13 steel regarding different processing strategies. Distortion in WAAM affects the part accuracy significantly and is therefore a problem which should be investigated. Temperature data were captured by thermocouples and the distortion was measured with a special measuring device during processing. The findings about distortion during processing thus show new results about the main influence on the final distortion. In general, the paper is well structured, the used methods were chosen properly, and the results are well-presented. Minor revision is necessary. The reviewer recommends the publication if following points are considered.
- The authors should show the machine set-up used for the experiments for better understanding of the experiments.
- In general, the authors should also show some images of the parts resulting from the different strategies in the results part.
- In Figure 5 the authors should mark the different layers to increase the understanding of the temperature curve during processing.
- In section 3.3, it is not clear what the authors mean with ‘Post-process distortion’. Please clarify. It is also not clear why the distortion in Figure 6 goes up to 16 mm but not in Figure 7.
- Section 4.4 is another experiment in the discussion part. It should be stated in the results part. Furthermore, it is not clear which deposition strategy has been used in this experiment.
- The scientific conclusions of the paper are not clearly formulated and concentrated mainly on the results. The main conclusion seems to be that the out-in strategy and additional cooling lead to the least distortions. The authors should formulate their conclusion more clearly.
Author Response
The paper presents results about the distortion in WAAM of H13 steel regarding different processing strategies. Distortion in WAAM affects the part accuracy significantly and is therefore a problem which should be investigated. Temperature data were captured by thermocouples and the distortion was measured with a special measuring device during processing. The findings about distortion during processing thus show new results about the main influence on the final distortion. In general, the paper is well structured, the used methods were chosen properly, and the results are well-presented. Minor revision is necessary. The reviewer recommends the publication if following points are considered.
- The authors should show the machine set-up used for the experiments for better understanding of the experiments.
√ We have added the figure of machine set-up for the experiments. Thanks for your suggestions.
- In general, the authors should also show some images of the parts resulting from the different strategies in the results part.
√ We have added the images of the parts produced by different strategies.
- In Figure 5 the authors should mark the different layers to increase the understanding of the temperature curve during processing.
√ Thanks for your good suggestion. We have marked the different layers in Fig.5 with dotted line.
- In section 3.3, it is not clear what the authors mean with ‘Post-process distortion’. Please clarify. It is also not clear why the distortion in Figure 6 goes up to 16 mm but not in Figure 7.
√ (1) Post-process distortion means that after the part is deposited and cools down to room temperature, the distortion of substrate is measured according to the method as shown in Fig.2. The comprehensive distance from each data point to fitted plane could be calculated by formula (3) to obtain the S value, which was applied to evaluate the distortion of the substrate.
(2) The reason for the different distortion between Fig.6 and Fig.7 is the change in the measurement area. The position of in situ distortion measurement is about 3mm near the free edge of the substrate, as shown in Fig.1 and Fig.3; the area for post-process distortion measurement was shown in Fig.2, the point of maximum distortion is 25 mm away from the free edge of the substrate. The closer the free end is, the greater the amount of distortion.
- Section 4.4 is another experiment in the discussion part. It should be stated in the results part. Furthermore, it is not clear which deposition strategy has been used in this experiment.
√ Dear professor, thanks a lot for your kind suggestion. It is reasonable for stating the water cooling experiments in the results part. Distortion can be reduced by path optimization and cooling condition, and both of them could be analyzed by the inherent strain method. Purpose of the cooling experiment was conducted to expand the application of inherent strain analysis in the field of additive manufacturing. So we think it might be more appropriate to state the cooling experiments in section 4.4. Sequence pattern was used in the water cooling experiment because of distinct distortion, the clarification was added in Page 12.
- The scientific conclusions of the paper are not clearly formulated and concentrated mainly on the results. The main conclusion seems to be that the out-in strategy and additional cooling lead to the least distortions. The authors should formulate their conclusion more clearly.
√ Thanks for your suggestion. We have modified the conclusion as your advice.
Author Response File: Author Response.pdf
Reviewer 4 Report
I give you vauale and mandatory suggestions to make a better manuscript, read the file carefully
Comments for author File: Comments.pdf
Author Response
We have here a serious and honest work, in which after applying a novel additive technique the authors wonder about residual stresses and ways to solve it. Recently there was a work in MDPI by Aurrekoetxea in Materials 2020, 13(6), 1445 about the residual stresses in large part, including the additive ones, you missed it. The method couples the effects of bulk residual stresses, machining stresses resulting from cutting loads on the surface and raw geometry of the blanks, and presents no size limitations. Experimental results confirm the capability of the proposed method to measure bulk residual stresses effectively and its practicality for industrial implementation. However a very good method is by Stoney equation, I read it in paper about coatings
https://doi.org/10.1080/10426914.2014.973582 to check the stresses on surface layers.
- In this particular design with a comb-like shape, showed in Fig. 1, vertical displacement of stress measurement sheet was related with his curvature, thickness and level of stresses by way of Stoney’s equation taking into account Poisson and film thickness limits.
- Your is an alternative, but you must discuss the topic better, including the above alternative, because this is absolutely related with your Figure 3…by the way, well concept to check distortions.
Figure 1, three thermocouples (TC1-TC3) were installed at the under-side of the substrate to record the temperature history. In order to investigate the influence of deposition patterns on distortion of substrate, four kinds of scanning patterns: sequence Deposition layers: you used 4 patterns, DOI 10.1007/s00170-014-6057-3 presented similar ideas when five –axis is let. Do you think five-axis can change your approach, please discuss it.
Methods and grammar are OK, the discussion of state of the art can be improved, good application and ideas. The work in Scripta Materalia is related with the main idea?
Dear professor, I’m very grateful to your comments for the manuscript. According with your advice, we amended the relevant parts in manuscript. Some of your questions were answered below.
(1) Recently there was a work in MDPI by Aurrekoetxea in Materials 2020, 13(6), 1445 about the residual stresses in large part, including the additive ones, you missed it.
√ We have reviewed and cited the paper by Aurrekoetxen et al. on bulk stress characterization.
(2) Yours is an alternative, but you must discuss the topic better, including the above alternative, because this is absolutely related with your Figure 3…by the way, well concept to check distortions.
√ We have reviewed and cited the paper by S. Rodríguez-Barrero et al. Their work on the dummy to calculate coating internal stress was very inspiring.
(3) You used 4 patterns, DOI 10.1007/s00170-014-6057-3 presented similar ideas when five –axis is let. Do you think five-axis can change your approach, please discuss it.
√ We have reviewed and cited the paper by Amaia Calleja et al. on the complex parts produced by 5-axis laser cladding process. I think the four deposition patterns proposed in our paper can be deposited by five-axis system. The structure of the parts fabricated by Amaia Calleja is more complex than that in our study, the 5-axis system is flexible enough for our study to produce the parts.
(4) The discussion of state of the art can be improved, good application and ideas. The work in Scripta Materalia is related with the main idea?
√ Some key factors (such as power, scanning speed and peak temperature, et al.) affecting the distortion in additive manufacturing were discussed in the work published in Scripta Materialia. They proposed that the thermal distortion was related to strain parameter as formula (9) and (10).
We can see that ε0 decreases with the increasing of inertia of moment of substrate (I). Through calculating we found that the moment of inertia of Case 4 (Out-In pattern) is larger over 11 % than Case 1 (Sequence pattern) after the deposition of each pass. The smaller distortion in Case 4 could be explained by the increasing of inertia of moment. So we think the work in Scripta Materialia is related with the idea of reduction in distortion.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Authors,
Your efforts are appritiate. The paper has been seriously improved. The description of methodology has been modified. Also, the scientific discussion has been added. In my opinion this paper could be published in this state.
Best regards,
Reviewer
Reviewer 2 Report
Despite the observation requested, no deepening on the microstructural or mechanical characteristics of the WAAM processed materials are provided. Having added one sentence on page 9, as stated, is not judged to be satisfactory.
