Improving Shipbuilding Steel Grade Quality at Stages of Smelting, Secondary Refining, and Continuous Casting
Round 1
Reviewer 1 Report
Pavel Kovalyov, Sergey Ryaboshuk and Aristotel Issagulov, Svetlana Kvon, Vitaly Kulikov
should be:
Pavel Kovalyov, Sergey Ryaboshuk, Aristotel Issagulov, Svetlana Kvon and Vitaly Kulikov
…in the range of 0,89-0,91 kg of…
should be:
…in the range of 0.89-0.91 kg of…
At the end of the introduction, please clearly describe the objectives of the work.
Figure 1 is not really clear.
The authors stated: “Vertical columns indicate the quantities, type and time of the added materials (deoxidizing, alloying, slag-forming agents)”.
Please specify in the text: deoxidizing, allowing and slag-forming agents.
Please precise also the amount of the “liquid steel” used for this investigation.
“…modification with calcium-containing reagents,…”
Please specify these calcium-containing reagents: (Ferro Calcium Silicon?)
Similar remark for other additives (Al, Ni, Mn).
It is difficult to identify the additive noted between FeSi and Mn (see the legend of Figure 1). Please check and modify.
Figure 2. Nonmetallic inclusion of the Al2O3-MgO-CaO system with 30% MgO…
Please give the type of analysis used to determine “30 % MgO in the Al2O3-MgO-CaO system”.
…aluminate compounds of 12CaO·7Al2O3 type with the CaS content up to 4% that,…
How did the authors identify this compound:12CaO·7Al2O3?
The authors gave many recommendations, but it is difficult to understand from “which raw data” these recommendations are issued.
The conclusion should be changed. It is roughly “copy & paste” of the second paragraph of the abstract (see below).
Abstract (second paragraph):
“It is shown that the main trends of improving the metallurgical quality of finished sheet products made of shipbuilding steel grades is to ensure the metallurgical heredity of continuous casting of billets that consists in providing the lowest possible degree of metal contamination by nonmetallic inclusions, harmful impurities and gases, forming a uniform fine-grained ingot structure, minimizing the central segregation heterogeneity as well as preventing formation of surface defects and defects in the macrostructure.”
Conclusion:
“Thus, the main trends of improving the metallurgical quality of finished sheet products made of shipbuilding steel grades is to ensure the metallurgical heredity of the CCB that consists in ensuring the lowest possible degree of metal contamination with nonmetallic inclusions, harmful impurities and gases, forming a homogeneous fine-grained ingot structure, minimizing the central segregation heterogeneity, and preventing formation of surface defects and defects in the macrostructure.”
At the whole, the work is more like a technical report than a research paper.
Author Response
Response to Reviewer’s 1 Comments
Point 1: Pavel Kovalyov, Sergey Ryaboshuk and Aristotel Issagulov, Svetlana Kvon, Vitaly Kulikov
should be:
Pavel Kovalyov, Sergey Ryaboshuk, Aristotel Issagulov, Svetlana Kvon and Vitaly Kulikov
Response 1: Pavel Kovalyov, Sergey Ryaboshuk, Aristotel Issagulov, Svetlana Kvon and Vitaly Kulikov
Point 2:…in the range of 0,89-0,91 kg of…
should be:
…in the range of 0.89-0.91 kg of…
Response 2: Corrected
Point 3: At the end of the introduction, please clearly describe the objectives of the work.
Response 3: The objective of this study is developing measures to improve the quality of shipbuilding steel grades such as S355G10, S420G2, S460G2 by adjusting the additives of aluminum and silicocalcium and adjusting the composition of the refining slags.
Point 4: Figure 1 is not really clear.
The authors stated: “Vertical columns indicate the quantities, type and time of the added materials (deoxidizing, alloying, slag-forming agents)”.
Please specify in the text: deoxidizing, allowing and slag-forming agents.
Please precise also the amount of the “liquid steel” used for this investigation.
Response 4: aluminum was used as a deoxidizing agent (secondary when discharging, then in the form of chaff) and ferrosilicon; the alloying agents were metallic manganese (Mn = 95%), ferromolybdenum (Mo = 60%), metallic nickel and ferroniobium; slag-forming lime.
The melting mass was 360t.
Point 5: “…modification with calcium-containing reagents,…”
Please specify these calcium-containing reagents: (Ferro Calcium Silicon?)
Similar remark for other additives (Al, Ni, Mn).
Response 5: Ferrocalcium was used as a calcium-containing reagent.
It is indicated above, in p. 4.
Point 6: It is difficult to identify the additive noted between FeSi and Mn (see the legend of Figure 1). Please check and modify
Response 6: The Figure has been corrected. This additive is CaO.
Point 7: Figure 2. Nonmetallic inclusion of the Al2O3-MgO-CaO system with 30% MgO…
Please give the type of analysis used to determine “30 % MgO in the Al2O3-MgO-CaO system”.
Response 7: The calculation of the content of oxide and sulfide components in the composition of each inclusion was performed based on the X-ray microanalysis data and the corresponding stoichiometric ratios between the elements. Verifying the phase composition was carried out using isothermal sections of triple state diagrams.
Point 8: …aluminate compounds of 12CaO·7Al2O3 type with the CaS content up to 4% that,…
How did the authors identify this compound:12CaO·7Al2O3?
Response 8: This note has been answered above. The composition of inclusions is based on the X-ray microanalysis the corresponding stoichiometric ratios between the elements.
Point 9: The conclusion should be changed. It is roughly “copy & paste” of the second paragraph of the abstract (see below).
Abstract (second paragraph):
“It is shown that the main trends of improving the metallurgical quality of finished sheet products made of shipbuilding steel grades is to ensure the metallurgical heredity of continuous casting of billets that consists in providing the lowest possible degree of metal contamination by nonmetallic inclusions, harmful impurities and gases, forming a uniform fine-grained ingot structure, minimizing the central segregation heterogeneity as well as preventing formation of surface defects and defects in the macrostructure.”
Conclusion:
“Thus, the main trends of improving the metallurgical quality of finished sheet products made of shipbuilding steel grades is to ensure the metallurgical heredity of the CCB that consists in ensuring the lowest possible degree of metal contamination with nonmetallic inclusions, harmful impurities and gases, forming a homogeneous fine-grained ingot structure, minimizing the central segregation heterogeneity, and preventing formation of surface defects and defects in the macrostructure.”
Response 9: Based on the comprehensive studies carried out, it was established that in order to improve the quality of shipbuilding steel grades of the S355G10, S420G2, S460G2 types in the course of its vacuuming, the amount of aluminum and silicocalcium added should be in the range 0.89-0.91 kg of aluminum per 1 kg of silicocalcium. For effective assimilation of inclusions it is recommended to strive to use refining slags close to the following composition: 50,00-55,00% CaO; 5,50-6,50% SiO2; 6,60-7,00% MgO; 31,00-33,00% Al2O3;<1% FeO.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
'three pilot melts': why these three? some experimental plan behind?
From line 144 on you state that based on your results you determine an optimal flow chart. For this paper your conlcusions should be drawn out of your results in a way that the reader can follow the reasoning therefore. Meaning that you should also include the necessary results for your argumentation.
line 30: 'exactly'
line 66-76, line 101-110: adjust line spacing
line 74: 'their introduction into'
line 103: 'of the production of'
line 113, 144: 'analysis of the production process'
You have '2017' or '2018' in the captions of the figures. Is there some meaning behind?
line 155, 156: 'If possible, the time of .. should be minimized.'
line 158: 'the faster the steel'
line 169: 'before introducing'
line 179, 180: 'stages of casting ladle-tundish ladle, as well as tundish ladle-mold.'
Author Response
Response to Reviewer’s 2 Comments
Point 1: 'three pilot melts': why these three? some experimental plan behind?
Response 1: We took part in the technological support of the production of the process of three pilot melts in the conditions of oxygen-converter production. Based on the previous laboratory studies there were determined the modes of producing the melts.
Point 2: From line 144 on you state that based on your results you determine an optimal flow chart. For this paper your conclusions should be drawn out of your results in a way that the reader can follow the reasoning therefore. Meaning that you should also include the necessary results for your argumentation.
Response 2: The chart is a graph of the melt temperature changing in the course of processing against the background of the material additives being applied at various stages. Vertical columns indicate the quantities, type and time of the analysis of the process of adding materials: aluminum was used as a deoxidizing agent (secondary when discharged, then in the form of chaff) and ferrosilicon; alloying agents were: metallic manganese (Mn = 95%), ferromolybdenum (Mo = 60%), metallic nickel and ferroniobium; slag-forming lime.
Point 3: line 30: 'exactly'
Response 3: line 29 (line 30 in the remark). The technological complexity of the process of obtaining high-quality shipbuilding steel is caused by the close interrelation of all technological conversions including the smelting of intermediate products, metal finishing and secondary, out-of-furnace refining, casting on continuous casting machines, roughing and finishing rolling of continuously cast billets (CCB) with exactly following the specified thermo-mechanical treatment that completes the process of obtaining rolled products.
Point 4: line 66-76, line 101-110: adjust line spacing
Response 4: adjusted the line spacing.
Point 5: line 74: 'their introduction into'
Response 5: line 71-72 (line 74 in the remark). The technology of deoxidizing and modifying steel, including their introduction into steel , the sequence and method of their introducing into the steel melt, should ensure the most complete removal of deoxidation products from the liquid metal, as well as the minimum content of nonmetallic inclusions in the finished metal [14-16].
Point 6: line 103: 'of the production of'
Response 6: line 107 (line 103 in the remark). In the present work, in order to develop technological recommendations aimed at improving the quality of shipbuilding steel grades of the S355G10, S420G2, S460G2 types, we took part in the technological support of the production of three pilot melts under the conditions of oxygen-converter production.
Point 7: line 113, 144: 'analysis of the production process'
Response 7:. line 115 (line 113 in the remark). Vertical columns indicate the quantities, type and time of the analysis of the process of adding materials: aluminum was used as a deoxidizing agent (secondary when discharged, then in the form of chaff) and ferrosilicon; alloying agents were: metallic manganese (Mn = 95%), ferromolybdenum (Mo = 60%), metallic nickel and ferroniobium; slag-forming lime.
line 164 ( line 144 in the remark).
Thus, based on analysis of the production process of three pilot melts of shipbuilding steel, as well as the results of the metallographic analysis of metal contamination and X-ray microanalysis of nonmetallic inclusions, the following optimal flow chart for the production of shipbuilding steel grades was determined.
Point 8: You have '2017' or '2018' in the captions of the figures. Is there some meaning behind?
Response 8: 2017 and 2018 denote the years of taking pictures and making diagrams.
Point 9: line 155, 156: 'If possible, the time of .. should be minimized.'
Response 9: line 175-176 ( line 155,156 in the remark). If possible, the time of steel discharging from the converter should be minimized (5-6 min).
Point 10: line 158: 'the faster the steel'
Response 10: line 178 (line 158 in the remark).As soon as possible, steel is purged with argon after the metal is discharged from the converter. In this case, the faster the steel begins to be purged with argon after the metal is discharged, the more favorable conditions are formed for the removal of nonmetallic inclusions.
Point 11: line 169: 'before introducing'
Response 11: line 183 (line 169 in the remark).The final aluminum deoxidation should be performed shortly before introducing the modifier into the metal. In addition, a more uniform introducing of alloying materials (FeNb, FeMo, Cu) should be ensured in the course of secondary refining with a single injected portion not exceeding 350 kg.
Point 12: line 179, 180: 'stages of casting ladle-tundish ladle, as well as tundish ladle-mold.'
Response 12: line 199-200 (line 179,180 in the remark). To minimize the effect of the metal secondary oxidation it is recommended to increase the tightness of the casting elements stages of casting ladle-tundish ladle, as well as tundish ladle-mold.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Figure 1 shows the flow chart of the secondary refining of shipbuilding steel, the melt mass 360t.
should be:
Figure 1 shows the flow chart of the secondary refining of shipbuilding steel, the melt mass was 360 tons.
…according to MRSA…
Please write full name of MRSA.
Author Response
Response to Reviewer’s 1 Comments
Point 1: Figure 1 shows the flow chart of the secondary refining of shipbuilding steel, the melt mass 360t.
should be:
Figure 1 shows the flow chart of the secondary refining of shipbuilding steel, the melt mass was 360 tons.
Response 1: Corrected
Point 2: according to MRSA…
Please write full name of MRSA.
Response 2: MRSA means X-ray microanalysis.
Author Response File: Author Response.pdf
Reviewer 2 Report
line 17: 'which makes it'
line 69: 'their introduction into'
line 77: which steel grades in detail are produced in the pilot melts?
line 111: spaces: 'Mn = 95%', 'Mo = 60%'
line 140, 151: What is the meaning of '2017' resp. '2018'? Year of the production of the pilot melt? Year when the picture for Fig. 2 was taken?
line 161: 'necessary, micro-alloying additives are added.'
line 163: Why '5-6 min'? Out of which observation, analysis this time spam is deduced?
line 171 'uniform introduction'
line 181: 'Al2O3, are'
line 182: spaces: [Al] < 0.01%'
line 187 f: From which observation the intensities of argon for purging are deduced?
Author Response
Responses to Reviewer’s 2 Comments
Point 1: line 17: 'which makes it'
Response 1: corrected
Point 2: line 69: 'their introduction into'
Response 2: The technology of deoxidizing and modifying steel, including their introduction into steel, the sequence and method of their introduction into the steel melt, should ensure the most complete removal of deoxidation products from the liquid metal, as well as the minimum content of nonmetallic inclusions in the finished metal [14-16].
Point 3: line 77: which steel grades in detail are produced in the pilot melts?
Response 3: In the pilot melts there are produced steels of S355G10, S420G2, S460G20 grades.
Point 4: line 111: spaces: 'Mn = 95%', 'Mo = 60%'
Response 4: line 112 (line 111 in the remark). Corrected.
Point 5: line 140, 151: What is the meaning of '2017' resp. '2018'? Year of the production of the pilot melt? Year when the picture for Fig. 2 was taken?
Response 5: line 142, 154 (line 140, 151 in the remark). 2017, 2018 denote the years of carrying out the studies
Point 6: line 161: 'necessary, micro-alloying additives are added.'
Response 6: line 164 (line 161 in the remark). If necessary, micro-alloying additives are added.
Point 7: line 163: Why '5-6 min'? Out of which observation, analysis this time spam is deduced?
Response 7: line 166 (line 163 in the remark). To minimize as possible the time of discharging steel from the converter for prevention of oxidation and decreasing the temperature of discharging. The production experience shows that the optimal time is 5-6 minutes. To reduce the time is technically impossible.
Point 8: line 171 'uniform introduction'
Response 8: line 177 (line 171 in the remark). In addition, a more uniform introduction of alloying materials (FeNb, FeMo, Cu) should be ensured in the course of secondary refining with a single injected portion not exceeding 350 kg.
Point 9: line 181: 'Al2O3, are'
Response 9: line 187 (line181 in the remark). Corrected.
Point 10: line 182: spaces: [Al] < 0.01%'
Response 10: line 188 (line 182 in the remark).Corrected.
Point 11: line 187: From which observation the intensities of argon for purging are deduced?
Response 11: line 195 (line 187 in the remark). These values have been obtained from the empirical observations when developing the technology of smelting the steel grades mentioned above.
Author Response File: Author Response.pdf
