Measurement and Model-Based Control of Solidification in Continuous Casting of Steel Billets

Round 1

Reviewer 1 Report

The laser vibrometer system focus on the physics of vibrations of a solid with some liquid core, the spectrum depends on the fraction of this liquid core, which allows to identify the crater end position in a strand of a CC machine. This reviewer saw this technology in reports, it was inspiring to found the industry application in the billet caster. The expression and the discussion were very good, several minor problems:

1.  For the analysis of FFT vibrometer data, the interval is 1s. How to evaluate this value, seem big for the FFT process?

2. There are significant differences in the transformed signal before and after the descaling system in Figure 6. What is the reason?

Author Response

Dear reviewer,

thanks for your evaluation and comments to our manuscript. You have raised two questions:

1. For the analysis of FFT vibrometer data, the interval is 1s. How to evaluate this value, seem big for the FFT process?

2. There are significant differences in the transformed signal before and after the descaling system in Figure 6. What is the reason?

Thus, we have amended the 2nd paragraph on page 9 as follows:

"The pre-processing has been performed by FFT of the raw vibrometer signal over measurement intervals of 1 second. Due to the mainly stationary casting conditions during the measurements, intervals of 1 to 60 seconds with frequency resolutions of 1 Hz to 1/60 Hz, respectively, are quite reasonable. This pre-processing step revealed significant differences in the transformed signal. However, these seemed to arise mainly from different characteristics of the positions themselves, e.g. due to the water jet of the descaling system evaporating on the strand surface (see Figure 6)."

We hope that the additional information clarifies your questions.

Best regards

Martin Schlautmann

Reviewer 2 Report

A mixture model on the continuous casting process was introduced in this work. A lot of data were collected and analyzed. This project is interesting and meaningful. Some suggestions are listed as follows.

1.       Please show some quantitative results in the abstract, such as the prediction of breakouts and surface defects, or some other important data.

2.       The section titles need modification: 2. Methodology (There is no material); 3. Results and Discussion; 4. Conclusions (A summary is necessary).

3.       In caption 3.3.1, a title No. 1/2/3 reused, preferably replaced by (1)/(2)/(3) or A/B/C.

Author Response

Dear reviewer,

thanks for your evaluation and comments to our manuscript. You have raised three issues:

1. Please show some quantitative results in the abstract, such as the prediction of breakouts and surface defects, or some other important data.

We have amended the last sentence in the abstract as follows:
"The application of the newly installed measurement and model-based information systems at ESF revealed significant improvements of their billet casting process in terms of halved strand breakout rates and correspondingly increased productivity."

With this amendment the abstract has the maximum allowed number of 200 words.

2. The section titles need modification: 2. Methodology (There is no material); 3. Results and Discussion; 4. Conclusions (A summary is necessary).

We have downloaded the template for the manuscript from the MDPI-website for the Applied Sciences journal. And this template contained the sections with titles as used in our manuscript. “Methodology” is called “Materials and Methods”. According to the template, a section “Conclusion” is not mandatory but can be added to the manuscript if the discussion is unusually long or complex. Our discussion section contains a summary of the performed work and achieved results, thus we skipped the conclusion section. 

3. In caption 3.3.1, a title No. 1/2/3 reused, preferably replaced by (1)/(2)/(3) or A/B/C.

We have replaced the enumerations 1/2/3 in subchapters of chapter 3 by (1)/(2)/(3).

We hope that the additional information clarifies your issues.

Best regards
Martin Schlautmann