Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States
, Yalong Zhang 1,2, Haipeng Liu 4 and Zhibing Wu 1,2Round 1
Reviewer 1 Report
Dear Authors,
Thank you for providing an improved version of your paper, now much more consistent.
Although deeply improved, there are minor amendments necessary to do in order to improve the overall quality of your paper. The comments can be found below:
- In the Bstract, line 23, you refer "...the wear less...Do you intend to refer the mass lost in the sample?
- In 3.1 and 3.3, don't be so sucint in the sections' name (CoF, WSR). Please use The extended name.
- You must change the term "Stable state" by "Steady state" when you are referring to friction.
- In line 329, please revise The sentence starting in "...and the surface materials are easily to be formed...".
- In The Introduction, please improve the explanation about the carbites formation, namely M2C and M5C2.
Good luck.
Kind regards
Author Response
Response to Reviewer 1 Comments
Comments and Suggestions for Authors
Dear Authors,
Thank you for providing an improved version of your paper, now much more consistent.
Point 1: Although deeply improved, there are minor amendments necessary to do in order to improve the overall quality of your paper. The comments can be found below:
Response: Dear reviewer, thank you for your valuable time, patient review and positive comments. We have carefully checked and revised the contents that need to be clarified in the manuscript.
Point 2: In the Abstract, line 23, you refer "...the wear loss...Do you intend to refer the mass lost in the sample?
Response: It is "volumetric wear loss", we have revised “wear rate” in the Abstract.
Point 3: In 3.1 and 3.3, don't be so succinct in the sections' name (CoF, WSR). Please use The extended name.
Response: Dear reviewer, we have corrected the abbreviations to the extended name in the revised manuscript.
Point 4: You must change the term "Stable state" by "Steady state" when you are referring to friction.
Response: In Section 3.1.1, we have changed the term "Stable state" by "Steady state".
Point 5: In line 329, please revise The sentence starting in "...and the surface materials are easily to be formed...".
Response: Dear reviewer, we have rephrased this sentence as "Furthermore, the lower hardness reduces the work hardening tendency, and the surface materials is prone to directional flow under the action of shear force, which indirectly reduces the WSR.".
Point 6: In The Introduction, please improve the explanation about the carbides formation, namely M2C and M5C2.
Response: We have added an explanation of the effects of carbide formation on wear resistance in the Introduction. Such as:
“Similarly, large amounts of alloying elements in alloy steels promote the precipitation of certain types of carbides (such as M2C and M5C2), which shows a positive effect on improving wear resistance [13, 14].”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear Authors,
the subject of this work is very interesting. However, the manuscript has a serious error that needs to be corrected before being published. Please refer to the suggestions in the attachment and make any appropriate changes.
Best regards,
Reviewer
Comments for author File: Comments.pdf
Author Response
Response to Reviewer 2 Comments
Dear Authors,
Point 1: the subject of this work is very interesting. However, the manuscript has a serious error that needs to be corrected before being published. Please refer to the suggestions below and make changes at work.
Response: Dear reviewer, thank you for your valuable time, patient review, positive and helpful comments. We have carefully checked and revised the contents that need to be clarified in the manuscript.
Point 2: Line 2 - The work doesn’t apply to fretting wear. Please read the comment - line 118. Please correct it.
Response: Dear reviewer, thank you very much for your comments. Firstly, micro-slip and high-frequency vibration are the main characteristics of fretting wear. The SRV testing machine ensures the contact between the upper and lower samples by applying pressure in the normal direction. At the same time, the swing arm is driven by the high-frequency vibration friction driven by an reciprocating motor. The SRV oscillating friction and wear tester is a professional test rig designed by Optimol company in Germany in 1975 to evaluate the fretting wear properties of materials. After decades of development, it has developed to the fifth generation of products.
Fretting wear is a typical synergic wear form due to small amplitude vibrations between mutually compressed metal surfaces. There are usually four wear mechanisms in fretting wear exist simultaneously: adhesive wear, abrasive wear, fatigue wear and corrosion/oxidative wear. Therefore, each of wear mechanisms contributes different degrees to fretting wear under different material states.
At present, many researchers around the world have reported their research on fretting wear behaviors of various materials based on SRV tester, and showed that the excellent stability and reliability of SRV test results. Such as the following references：
- Amanov, A.; Umarov, R. The effects of ultrasonic nanocrystal surface modification temperature on the mechanical properties and fretting wear resistance of Inconel 690 alloy, Appl. Surf. Sci. 2018, 441, 515-529.
- Wang, M.; Wang, Y.; Liu, H.; Wang, J.; Yan, F. Interrelated effects of temperature and load on fretting behavior of SAF 2507 super duplex stainless steel, Tribol. Int. 2019, 136, 140-147.
- Kumar Dubey, M.; Bijwe, J.; Ramakumar, S. S. V. PTFE based nano-lubricants, Wear 2013, 306, 80-88.
- Rustamov, I., Zhang, G., Skotnikova, M., Wang, Y., & Wang, Z. Fretting Wear behavior and damage mechanisms of Inconel X-750 alloy in dry contact condition, J. Tribol-T ASME 2019, 141.
Secondly, according to the generally accepted theory of three-body wear mechanism, typical fretting wear will develop in four stages as shown in the Reference figure 1 below:
In stage â‘ , the surfaces of the two contact pairs are in direct contact, and the asperities on tribo-pair surface are embedded into each other. Since the contact area is small, the coefficient of friction is low. In stage â‘¡, the surfaces of the two contact pairs are still in direct contact, but the coefficient of friction increases gradually due to the adhesion of tribo-pair surface. After entering the stage â‘¢, the asperity begins to peel off and form the wear debris, the two-body contact turns into three-body contact, the adhesive wear is inhibited, and the coefficient of friction gradually decreases. When entering the stage â‘£, the formation and discharge of wear debris continuously, to achieve a steady dynamic balance.
Therefore, it can be seen from Figure 4 in the manuscript, the wear development trend of each material state is completely consistent with the "three-body contact" theory of fretting wear.
Reference figure 1. The relationship between the CoF of fretting wear and fretting test time.
In summary, in this paper, 25CrNi2MoVE steel is taken as the research target, and the correlations of wear behaviors and microstructure, grain properties and carbide precipitates of torsion shaft for special field vehicles under different tempering states is systematically studied and discussed by using the SRV â…£ tester. Moreover, it can be seen from Figure 4 in the manuscript that the test results was consistent with the fretting wear theory. Therefore, we think it is appropriate to call fretting wear in the manuscript.
Point 3: Line 83 - Why such accuracy of result (e.g. for N, P, O...)? Why was oxygen added to the chemical composition? Please correct it.
Response: Dear reviewers, the contents of each element of 25CrNi2MoVE steel shown in Table 3 strictly follow the quality certificate provided by a commercial manufacturer, as shown in Reference figure 1 below. Because the content of each element in different batches of raw steel is different, we decided to adopt the reported content of the batch of raw steel we used in our paper after comprehensive consideration. Among them, the oxygen element presented in Table 3 is the impurity element introduced in the smelting process of steel. As shown in Reference figure 2, the oxygen content in 25CrNi2MoVE steel should not be higher than 0.0035%.
Reference figure 2. The quality certificate of raw 25CrNi2MoVE steel provided by a commercial manufacturer.
Point 4: Line 111 - Why 20 kV and not more?
Response: Based on the EDS analyses with many times, we found that the acceleration voltage of 15~25 kV had little effect on the detection of element types in 25CrNi2MoVE steel, and repetitive qualitative analysis results could be obtained under the acceleration voltage of about 20 kV.
Point 5: Line 118 - This test can not be called a fretting test.
Fretting wear is the abrasive and corrosive wear consisting in destruction of the surface layer. The process consists in the formation of local material losses in machine elements that are subjected to vibrations or slight slips arising as a result of these elements rotating or reciprocating movement or their movement under the influence of cyclic loads, as well as the intense influence of corrosive environment.
Response: Dear reviewer, thank you very much for your comments. As mentioned above, we think it is appropriate to call fretting wear, and sincerely hope you can consider it.
Point 6: The mechanically damaged element is therefore attacked by corrosion, which reduces its strength and leads to increased damage.
So where can the corrosive effects of the environment be seen?
Please correct it.
Response: Dear reviewer, thanks for your comments, this is an interesting topic. We think that the corrosion wear in the fretting you mentioned is not the “corrosive effects of the environment”, but the oxidative corrosion caused by local increased temperature during the fretting wear. This has been mentioned in many research reports, and sometimes they equate corrosion wear with oxidative wear, or directly call it oxidative wear. Such as:
- Karanjai, M.; Kumar, B. M.; Sundaresan, R.; Basu, B.; Mohan, T. R.; Kashyap, B. P. Fretting wear study on Ti–Ca–P biocomposite in dry and simulated body fluid, Sci. Eng. A 2008, 475, 299-307.
- van Dijk, P.; van Meijl, F. A design solution for fretting corrosion. In Electrical Contacts-1996. Proceedings of the Forty-Second IEEE Holm Conference on Electrical Contacts, Joint with the 18th International Conference on Electrical Contacts IEEE 1996, 375-382. .
- Hoeppner, D. W.; Chandrasekaran, V. Fretting in orthopaedic implants: a review, Wear 1994, 173, 189-197.
- Conner, B. P.; Hutson, A. L.; Chambon, L. Observations of fretting fatigue micro-damage of Ti–6Al–4V, Wear 2003, 255, 259-268.
- Ren, W.; Wang, P.; Fu, Y.; Pan, C.; Song, J. Effects of temperature on fretting corrosion behaviors of gold-plated copper alloy electrical contacts, Int. 2015, 83, 1-11.
In addition, the dry friction test condition was applied in this study, so the effect of corrosion environment on the experimental results was avoided. The sources of environmental corrosion effects are various, such as acid substances brought by deteriorated lubricating oil and salts in seawater, etc. However, these factors are complicated and will bring uncertain interferences to the study of the effect of tempering states on the wear behaviors of torsion shaft material. Also, these fretting wear studies under specific corrosion conditions will be our next work.
Point 7: Line 133 - This test can not be called a fritting test. Please correct it.
Response: Dear reviewer, as mentioned above, we think it is appropriate to call fretting wear, and sincerely hope you can consider and accept it.
Point 8: Line 298 - Fig. 10 e,f,g - The result for carbon can't be reliable. Please explain this. Please correct it.
Response: Dear reviewer, thanks again for your valuable and constructive comment. We knew that the EDS results are qualitative analysis. After consulting many teachers and professional technicians in our country, we agreed with your opinion. We ignored the carbon pollution in the SEM equipment, which caused the deviation of the quantitative analysis results of carbon elements. Therefore, we decided to delete the description of the quantitative analysis in the manuscript and the element content table in Figure 10e-g, leaving only the energy spectrum curve as the basis for the qualitative analysis of Mo and Cr element. The correction mainly in Section 3.3.1 and Section 3.4, which had little influence on the obtained conclusions.
Point 9: Line 473 - Fig. 13 b - 2.23um dimension was incorrectly marked in relation to the photo scale - 50um. Fig. 13 c,d - Do You think the results for carbon by EDS are reliable? Please correct it.
Response: According to your comments, we have re-measured the ploughing, the maximum width is about 5.4 μm, and the result has been revised in the manuscript. Due to the inaccurate quantitative analysis of carbon element, we decided to delete the element content table in Fig. 13c, d and we just retained the energy spectrum curve for qualitative analysis of oxygen element.
Author Response File: Author Response.pdf
Reviewer 3 Report
The topic of this work “ Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States” is very interesting and may attract the research community.
Despite of this some issue needs to be clarified.
The introduction is very brief.
In which industry and application do you want to use these fundamental research.
There are not details how the Fretting Wear is overcome and measured in literature
Which is the fundamental question that you want to solve through this research ?
Only 16 references in introduction make your research poor
Please use a citation after this “Eldis” not at the end of phrase
In which base were selected the parameters from Table 3
It be possible to introduce a colour bar legend for Figure 6 to understand how deep is the wear ?
Indeed it is appreciated that you measured average surface roughness Ra as an indicator for wear but for my experience the Rz is the best to indicate the wear progress
You plotted a nice Figure 10, 11 with the microstructure but there is not any explanation for the sample preparation in method and materials part
There is some indication of wear in Figure 13 a but please put some arrows for other caption in order to indicate the wear mechanism
Author Response
Response to Reviewer 3 Comments
Comments and Suggestions for Authors
Point 1: The topic of this work “ Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States” is very interesting and may attract the research community.
Response: Dear reviewer, thank you very much for your patient review and constructive comments. We have carefully checked and revised the contents that need to be clarified in the manuscript.
Despite of this some issue needs to be clarified.
Point 2: The introduction is very brief.
Response: Dear reviewer, thanks for your constructive comments, we have improved the Introduction, which have been marked in yellow background in the revised manuscript.
Point 3: In which industry and application do you want to use these fundamental research.
Response: Torsion shaft is an important elastic component in the suspension system of special field vehicles. In working conditions, the torsion shaft will be subjected to greater shear stress along the axis and transverse direction. Coupled with the violent vibration during the operation of the vehicle, it is easy to induce the fretting wear of the shaft end and promote the breaking of the torsion shaft. Therefore, this work discusses the fretting wear characteristics of typical torsion shaft materials of special field vehicle under different tempering heat treatment conditions. At present, there are few similar studies. Therefore, the research conclusions would have great significance for reducing the wear failure of key transmission components of vehicles under the increasing operation intensity. Furthermore, many current studies in the research area of tribology have focused on advanced composite materials, such as high entropy alloys, titanium alloys, and gradient alloys. However, the cost-efficient production of modern high strength steels still make them a very competitive option for the wear-applications. For a considerable period of time, the development of novel alloy steels suitable for different and increasingly harsh working conditions is still needed. In this paper, a novel high strength alloy 25CrNi2MoVE steel is taken as the research target, and the direct correlations between microstructure, carbide precipitation and fretting behavior is studied. Based on the analysis of wear mechanisms, the theoretical basis can be referenced for the development of other new wear-resistant and high-strength steels.
Point 4: There are not details how the Fretting Wear is overcome and measured in literature.
Response: Fretting wear is unavoidable for the torsion shaft, so the material can only obtain the best wear resistance by adjusting the heat treatment process. As mentioned in the manuscript, we obtained the optimal tempering process with minimum fretting wear volumetric wear rate and coefficient of friction (that is, tempering at 350℃ after quenching) through the experimental conclusions.
We have presented the measurement details of fretting wear in Section 2.3 of the manuscript, such as
“At least three fretting tests were carried out in each material state and used to calculate the steady coefficient of friction (CoF).”
“Before and after fretting wear test, the sample was cleaned and dried in 50% petroleum ether alcohol solution. A universal 3D profilemeter (UP series, Retc-instruments, USA) was used to measure the profile of wear scar, and the length (x), width (y), depth (z) were obtained with the accompanying Gwyddion software (Version 2.44, Czech metrology institute, Czech Republic). ”
“The depth, length and width of the wear scar measured at least three times were used to evaluate the Kv value.”
Point 5: Which is the fundamental question that you want to solve through this research ?
Response: Dear reviewer, as mentioned above, this work mainly takes the novel high strength 25CrNi2MoVE steel used in the torsion shaft of special field vehicles as the research target. This manuscript clarifies the effect of different tempering conditions on the fretting wear resistance of the torsion shaft. Meanwhile, based on analyzing the correlation among microstructure, carbide precipitation, fretting behavior and wear mechanism under each tempering state, the theoretical basis can be provided for the development of new wear-resistant steel and reducing the adverse effect of fretting wear as far as possible.
Point 6: Only 16 references in introduction make your research poor.
Response: We have improved the Introduction and added some references [13-14] and [16-19]; there are now 22 references in the Introduction.
Point 7: Please use a citation after this “Eldis” not at the end of phrase.
Response: Dear reviewer, we have made corrections in the Line 113.
Point 8: In which base were selected the parameters from Table 3.
Response: The SRV oscillating reciprocating friction and wear tester is the mainstream test device to study fretting wear in the world. Meanwhile, according to a large number of our experimental results, the status of tester is the very stable under the frequency of 20 Hz, and the test results obtained are reliable and repeatable. Similarly, preloading 5 N and running for 5 min is also to obtain stable test results. As shown in Figure 4 in the manuscript, after continuous wear for 30 min under the condition of 45 N normal load, the samples under most tempering states can be guaranteed to enter the steady wear stage. These similar optimization test parameters have been reported in many of our researches, such as:
- Duan, Y.; Qu, S.; Li, X. Effect of quench-tempering conditions prior to nitriding on microstructure and fretting wear mechanism of gas nitrided X210CrW12 steel, Coat. Tech. 2019, 360, 247-258.
- Li, G.; Qu, S. G.; Pan, Y. X.; Li, X. Q. Effects of the different frequencies and loads of ultrasonic surface rolling on surface mechanical properties and fretting wear resistance of HIP Ti–6Al–4V alloy, Surf. Sci. 2016, 389, 324-334.
- Lai, F.; Qu, S.; Lewis, R.; Slatter, T.; Fu, W.; Li, X. The influence of ultrasonic surface rolling on the fatigue and wear properties of 23-8N engine valve steel, J. Fatigue 2019, 125, 299-313.
Therefore, the test parameters in Table 3 were selected for our research after comprehensive consideration.
Point 9: It be possible to introduce a colour bar legend for Figure 6 to understand how deep is the wear ?
Response: Dear reviewer, we have added the colour bar in Figure 6.
Point 10: Indeed it is appreciated that you measured average surface roughness Ra as an indicator for wear but for my experience the Rz is the best to indicate the wear progress.
Response: Based on your suggestion, we have adjusted the roughness indicator from Ra to Rz, and we have obtained a similar conclusion. These changes have been highlighted in Section 2.4 and 3.1.3.
Point 11: You plotted a nice Figure 10, 11 with the microstructure but there is not any explanation for the sample preparation in method and materials part.
Response: Dear reviewer, as mentioned in Section 2.2, all of the samples were polished and etched with 4% Nital solution to reveal the metallographic structure features.
Point 12: There is some indication of wear in Figure 13 a but please put some arrows for other caption in order to indicate the wear mechanism.
Response: Based on your suggestion, we have added the arrow annotations in Figure 13e-n. As shown in below figure：
Figure 13. SEM morphologies and energy spectra of worn surface: Magnification of AR state (a) at 400× and (b) at 1600×; EDS spectrum of (c) spot 4 (unworn surface) and (d) spot 5 (transferred debris); Magnification of (e) N850, (f) NT200, (g) NT350, (h) NT550, (i) NT850, (j) NQ850, (k) NQT200, (l) NQT350, (m)NQT550 and (n)NQT850 state.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Dear Authors,
the presented arguments and changes introduced to manuscript are sufficient to publish the work. Nevertheless, in line 105 - Table 1, the data source (steel producer) should be completed.
Best regards,
Reviewer
Author Response
Response to Reviewer 2 Comments
Dear Authors,
Point 1: The presented arguments and changes introduced to manuscript are sufficient to publish the work. Nevertheless, in line 105 - Table 1, the data source (steel producer) should be completed.
Response: Dear reviewer, we sincerely thank you for your constructive comments on our manuscript and your affirmation of our revision. According to you suggestion, we have added manufacturer information that provides chemical composition data, as shown in Line 100.
Best regards.
Shengguan Qu
Fuqiang Lai
Author Response File: 
Author Response.docx
Reviewer 3 Report
The authors made the nececsary correction, therefore, the paper shpuld be considered for publication
Author Response
Response to Reviewer 3 Comments
Comments and Suggestions for Authors
Point 1: The authors made the necessary correction, therefore, the paper should be considered for publication
Response: Dear reviewer, we sincerely thank you for your constructive comments on our manuscript and your affirmation of our revision.
Best regards.
Shengguan Qu
Fuqiang Lai
Author Response File: Author Response.docx
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
Dear Authors,
The work is interesting and indicate the high scientific soundness of authors.
Requires minor changes according to the notes below:
Line 81: Table 1 - Please rank elements according to their importance for 25CrNi2MoVE alloy.　
What measuring method has the chemical composition been determined?
Line109: Why 20 kV and not more?
Line268: Fig. 8e,f,g - Do You think the EDS results for carbon are reliable?
Line415: Fig. 11b - 2.23um dimension was incorrectly marked in relation to the photo scale.
Fig. 11c,d - Do You think the EDS results for carbon are reliable?
Best regards, Reviewer
Reviewer 2 Report
Dear Authors,
Congratulations on your work which is very well written and organized. The issue is not new, just the material is different from other studies. However, your study is mainly focused on how the heat treatments affect the microstructure, and on how the microstructure affects the wear behaviour. Thus, other important issues in surface science are being forgotten, namely the surface state. In the surface photos it is possible to observe intense roughness. However, this issue is not treated during your work. Moreover, the wear is treated just as fretting wear. However, as you tell in your work, there are debris resulting from the movement and contact. Thus, 3-body abrasion should be considered. Moreover, the peaks of the asperities surface will result in debris, whose affect the wear mechanisms. Thus, your work must be redesign in order to include these analysis.
There are other minor concerns in your work, but the concerns above referred are enough to identificar serious flaws those cannot be ignores and avoid my recommendation to publish the paper in the current form.
Thus, I'm encouraging you to deeply improve your work in these Master's before ner submission.
kind regards,
Reviewer 3 Report
Paper title:
Effects of microstructure evolution on fretting wear behaviors of 25CrNi2MoVE steel under different tempering states
This paper investigates the evolution of the microstructure and fretting wear behaviors of 25CrNi2MoVE torsion shaft steel and their influence on the wear mechanisms as a function of tempering temperature
The problem statement is well described, and the experimental set-up is detailed.
Comments:
The results presented in figure 3 (coefficient of friction results) need to be justified. The link between the microstructure of the different states and the wear mechanisms is not clear in the manuscript
