Surface Damage Analysis on the Application of Abrasion and Slurry Erosion in Targeted Steels Using an Erosion Test Rig

Round 1

Reviewer 1 Report

Dear Authors,

Important point to consider in order to improve the manuscript's quality.

Do not enter the materials' names as A B C R. Should include the exact name of the material.

Remove the fresh words from fresh martensite from Table 2.

Fig. 2. Maintain the exact experiment figure rather than modifying it.

How do you determine the test parameters? Prove it using the optimization method. Justify your reasons for going above and below the optimal value.

Figure 3 should be clear and maintain a high-resolution image with large size to understand all of the components.

Draw and analyze the wear rate and resistance, as well as the COF, in relation to the input values.

Author Response

Important point to consider in order to improve the manuscript's quality.

The authors are grateful for the valuable suggestions. The manuscript has been adjusted and changes have been indicated. In this writing we also state our position on individual remarks.

• Do not enter the materials' names as A B C R. Should include the exact name of the material.

The present work was carried out within the framework of a project that is bound by Intellectual Property constraints. The materials present in this investigation are proprietary and further information cannot be disclosed.

• Remove the fresh words from fresh martensite from Table 2.

Thank you for the suggestion, the Table 2 was updated accordingly.

• 2. Maintain the exact experiment figure rather than modifying it.

Figure 2 shows a 3D model of the test set-up and the most important parts of it (disc with mounted specimen in the pot and specimen configuration angles similarly as in the exact experiment described). Figure 3 shows the actual test setup.

• How do you determine the test parameters? Prove it using the optimization method. Justify your reasons for going above and below the optimal value.

Pre-tests confirmed the optimal operation parameters. Based on experience from pre-tests, the fragmentation of the Al₂O₃ was not significant after 20 hours of operation, and there was also no significant dry-out of the slurry to change the ratio. Testing velocity was set to match the range of a targeted agricultural application (soil plough dragged with 8-12 km/h) and testing time was set to provide enough wear for sufficient ranking.

• Figure 3 should be clear and maintain a high-resolution image with large size to understand all of the components.

Thank you for the notice, Figure 3 has been updated.

• Draw and analyze the wear rate and resistance, as well as the COF, in relation to the input values.
  A new figure (Figure 4) and explanatory text inserted to the manuscript. “The mass decreased linearly in the function of sliding distance and specimen placement in case of all specimens. Samples mounted on radius 105 mm resulted in severe mass loss in the case of all tested materials, as can be seen in Figure 4. This high mass loss on radius 105 mm was unexpected as the wear severity is supposed to increase with higher speed operation. The second most severe wear was observed on the specimen mounted on radius 65 mm. Even though all of the specimens were aligned 45° to the abrasive particle flow, their orientation had a more significant effect on the wear of these materials. The slurry pot samples mounted to face the centre shaft (centre of rotation), namely on radii 65 and 105 mm suffered more severe wear. Hence, the effect of specimen orientation (angle of attack) had a more significant role in the wear severity than the dif-ference in the radius (higher testing speed). The severe wear on the specimen oriented to-wards the centre shaft could be explained by the effect of the centrifugal force on the slurry. The centrifugal force pushes the abrasive particles in a radial direction to the in-side-oriented specimen surfaces, resulting in more severe material removal.”

Author Response File: Author Response.docx

Reviewer 2 Report

This study investigated the wear resistance of steel under slurry abrasion and erosion conditions. The angle and velocity was considered to explore the wear mechanisms. It was significant to develop advanced shaft for future erosion applications.

However, there are some problems to be clear before accept.

1.      For erosion, material property is a key point. For abrasion, abrasive particle size, velocity, shape, angle, time and others all had an influence on the wear rate of steel. Why you only studied the angle 45°？Theoretically, small impacting angle will produce cutting effect and big angle will produce impact effect.

2.      The abrasive mechanisms need to be corrected along abrasive (maybe only mechanical effect) and erosive (should be had chemical effect). You should provide such evidence to support your mechanism analysis and discussion.

3.      Some spell mistakes should be corrected, for example, sulrry in Figure 1, should slurry.

Author Response

This study investigated the wear resistance of steel under slurry abrasion and erosion conditions. The angle and velocity was considered to explore the wear mechanisms. It was significant to develop advanced shaft for future erosion applications.

However, there are some problems to be clear before accept.

Thank you very much for your constructive advices. The suggested corrections have been adapted in the manuscript and changes have been indicated. In this writing we also state our position on individual remarks.

1. For erosion, material property is a key point. For abrasion, abrasive particle size, velocity, shape, angle, time and others all had an influence on the wear rate of steel. Why you only studied the angle 45°？Theoretically, small impacting angle will produce cutting effect and big angle will produce impact effect.

Figure 5 shows the “Mass loss [%/100 km] normalized with sliding distance in the function of the angle to the abrasive flow of a) material A on radius 125 and 105 mm and b) material B on radius 85 and 65 mm.” The wear severity of specimens with radii of 65, 85, and 125 mm was ranked as follows: 30°<60°<45°. In this case, the lowest wear corresponded to a specimen oriented 30° to the medium flow, whereas the greatest corresponded to 45°. However, in the instance of a radius of 105 mm, the alignment sequence was 60°<45°<30° as wear severity increased.

2. The abrasive mechanisms need to be corrected along abrasive (maybe only mechanical effect) and erosive (should be had chemical effect). You should provide such evidence to support your mechanism analysis and discussion.

Thank you for the comment. From the contact during the operation the wear mechanism could be theoretically already suspected, however the post mortem characteristic wear damage provides verification for the mechanism. High-speed video recordings highlighted the varied contact conditions that caused the wear mechanism to shift from abrasion to slurry erosion. Slurry abrasion was seen at the bottom of the specimen as a result of pure sliding conditions, while pitting was observed at the top of the specimen as a result of fatigue from particle impact (Figure 6, 7). 3D surface studies (Figure 8) demonstrated a decrease in wear rate while transitioning from the abraded zone, which witnessed polishing and minor hardness, to the pitting zone.

3. Some spell mistakes should be corrected, for example, sulrry in Figure 1, should slurry.

The authors are grateful for the notice. The whole document is reviewed and spelling mistakes are corrected, Figure 1 also updated.

Author Response File: Author Response.docx