Influence of Electrolytic Hydrogen Charging and Effusion Aging on the Rotating Bending Fatigue Resistance of SAE 52100 Steel

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

My comments are attached. 

Comments for author File: Comments.pdf

Author Response

Please see the enclosed Word-file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript investigates the influence of hydrogen embrittlement on the rotating bending fatigue performance of quenched and tempered SAE 52100 (100Cr6) bearing steel. While the topic aligns with the scope of the CMD the current version of the manuscript has several significant shortcomings that preclude its acceptance. The experimental dataset is limited and insufficient to support the general conclusions. Only two figures contain primary data, which is inadequate for a fatigue study involving multiple variables such as heat treatment conditions, hydrogen charging, and ageing time. Second, the study confirms well-known trends—namely, that hydrogen degrades fatigue life and that annealing can partially recover performance—without offering any significant novelty in materials, methodology, or mechanistic understanding.

Author Response

Please see the enclosed Word-file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This article gives an insight on how SAE 52100 steel cracking by bending stress is influenced by annealing. It gives a valuable input on different hydrogen induced failures related to this kind of steel.

Some comments

The article suffers from speculations that could be substantiated by extending the material analyses.

1. Charging depth of H could be recorded by the use of GDOE, SNMS or SIMS
2. Apart from fracture analyses FIB /SEM would better prove the assumed hypothesis of inter – respectively trans granular fracture
3. FIB/SEM further could prove the impact of electrolytic charging, whether of/not pores have been created subsurface.
4. For specimen B it is obvious that the microstructure is different compared to original SAE 52100 (e.g. sizes of carbides)

 

Line 43         

Is it really low potential energy ? Locally stress and hence the chemical potential near to vacancies, dislocations and NMI is supposed to be high.

 

Line 80

How is the assumed relation between hydrogen impact and hardness

 

Line 97

Can you explain why this prevents chemical attack

 

Line 104/105

Why not proven by SNMS, SIMS or GDOES

 

Line 109/110

A picture would be helpful

Comments for author File: Comments.pdf

Author Response

Please see the enclosed Word-file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors did not include any additional experiments in the revised manuscript. For example, the dimensions of the fatigue test samples remain unclear. Moreover, none of the experimental data include error bars, suggesting that each experiment may have been performed only once. Considering that this is not a letter-type paper, the overall amount of work presented is insufficient to justify acceptance in its current form.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks for revising. Paper is fine for being published.

Author Response

Thank you very much again for your review.

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

I have no further comments.