Smelting method of 10CrNiCu steel for naval vessels and 10CrNiCu steel for naval vessels

Abstract

The embodiment of the invention provides a smelting method of 10CrNiCu steel for a naval vessel and the 10CrNiCu steel for the naval vessel. According to the smelting method provided by the invention, a KR-BOF-LF refining + RH refining-CC continuous casting process route is adopted, and a continuous casting slab with excellent surface quality and internal quality can be obtained by controlling parameters and the content of each element component in the steel production process, so that the relatively harsh quality requirement of a 10CrNiCu product is met, and the production cost is reduced. The inclusions A, B, C and D of the middle steel plate material are controlled to be not more than 1.0, and the DS is not more than 2.0; the center of the plate blank is segregated, the center porosity does not exceed C1.5, and the equiaxed crystal rate is 15% or above.

Description

Technical Field

[0001] The present application belongs to the field of steel, and in particular, relates to a smelting method of 10CrNiCu naval vessel and marine steel and 10CrNiCu naval vessel and marine steel. Background Art

[0002] As global energy and natural resources become increasingly scarce, more and more countries are exploring low-temperature waters, so the demand and requirements for ship steel in low-temperature waters are increasing day by day. 10CRNICU ship steel is a high-strength hull structural steel with good weldability, corrosion resistance and high toughness mechanical properties. Its use in hull structures is expanding.

[0003] The improvement of ship performance indicators has put forward higher requirements on the performance of ship steel. The steel plate material needs to have high toughness at extremely low temperatures, the material needs to have high smelting cleanliness, light central segregation of the ingot, high equiaxed crystal ratio and other good internal qualities. Summary of the invention

[0004] The embodiments of the present application provide a smelting method for 10CrNiCu naval vessel steel and 10CrNiCu naval vessel steel, which can produce continuous casting slabs with excellent surface quality and internal quality to meet the more stringent quality requirements of 10CrNiCu products.

[0005] In the first aspect, the embodiment of the present application provides a smelting method of 10CrNiCu ship and marine steel, comprising the following steps: subjecting molten iron to KR treatment and then transferring it to a converter for smelting to obtain converter molten steel, wherein the iron-water ratio in the charge of the converter is not less than 0.80; tapping the converter molten steel to an LF refining furnace for deoxidation and alloying smelting to obtain a first refined molten steel, wherein the tapping temperature of the converter molten steel meets 1680-1700°C; transferring the first refined molten steel to an RH refining furnace for vacuum smelting to obtain a second refined molten steel; casting the second refined molten steel to obtain 10CrNiCu ship and marine steel, wherein the 10CrNiCu ship and marine steel comprises a molten steel having a mass of 100%; and a molten steel having a mass of 100%; wherein the molten steel has ... The following components are measured by content: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, 0.65wt%≤Cr≤0.75wt%; the rest are iron and other inevitable impurities.

[0006] According to an embodiment of the first aspect of the present application, when the molten iron is subjected to KR treatment, the temperature of the molten iron is not lower than 1280°C, and after the molten iron is subjected to KR treatment, the S content does not exceed 0.005%, and the post-slag cleanliness is not lower than 85%.

[0007] According to an embodiment of the first aspect of the present application, Ni, Fe alloys and scrap steel are added during smelting in the converter, Cr and Cu alloys are added when the molten steel from the converter is tapped, and the Ni, Cr and Cu alloys are adjusted to above 85% of the target composition when the molten steel from the converter is tapped.

[0008] According to an embodiment of the first aspect of the present application, a slag blocking + slag retaining operation is adopted when the molten steel in the converter is tapped, and the end point P does not exceed 0.012%.

[0009] According to the embodiment of the first aspect of the present application, in the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, the temperature during the transfer needs to meet the requirement of 1620-1635°C.

[0010] According to the embodiment of the first aspect of the present application, in the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, it circulates for 8 to 12 minutes at a vacuum degree of ≤100 Pa, and then 0.25 to 0.35 Kg / T of lanthanide rare earth alloy is added and circulated for 3 to 5 minutes.

[0011] According to the embodiment of the first aspect of the present application, in the step of casting the second refined molten steel, the casting speed is controlled at 1.1-1.3 m / min, the wide surface of the first cold strength crystallizer is controlled at 3800-4200 L / min, the narrow surface of the crystallizer is 550-650 L / min, and the second cold strength specific water volume is 0.55-0.75 m 3 / t, adopts three-stage dynamic light pressing mode, and the three-stage pressing amount is 3.0-4.5mm.

[0012] In the second aspect, an embodiment of the present application provides a 10CrNiCu naval vessel steel, including the following components in mass percentage: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, 0.65wt%≤Cr≤0.75wt%; the rest are iron and other inevitable impurities.

[0013] According to the embodiment of the second aspect of the present application, the center segregation and center porosity of the slab of 10CrNiCu ship and marine steel do not exceed C1.5, and the equiaxed crystal ratio meets 15% or more.

[0014] Compared with the prior art, the embodiments of the present application have at least the following beneficial effects:

[0015] The smelting method of 10CrNiCu naval vessel steel in the embodiment of the present application adopts the KR-BOF-LF refining + RH refining - CC continuous casting process route. By controlling the parameters in the steel production process and the content of each element component, a continuous casting slab with excellent surface quality and internal quality can be obtained to meet the relatively stringent quality requirements of 10CrNiCu products, so that the inclusions A, B, C, and D of the steel plate material in 10CrNiCu are controlled not to exceed 1.0, and the DS inclusions are not more than 2.0; the center segregation and center porosity of the slab do not exceed C1.5, and the equiaxed crystal rate is above 15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Features, advantages, and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0017] Figure 1 is a low-power microscopic schematic diagram of the 10CrNiCu ship and marine steel of Example 1 of the present application;

[0018] Figure 2 This is a low-magnification microscopic diagram of the 10CrNiCu ship and marine steel of Comparative Example 1 of the present application;

[0019] Figure 3 It is a low-magnification microscopic schematic diagram of the 10CrNiCu ship and marine steel of comparative example 2 of the present application. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0021] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0022] The inventors of the present application provide a smelting method for 10CrNiCu naval vessel steel and oriented silicon steel, which can control the inclusions of A, B, C, and D types in the steel plate material to not exceed 1.0, and the DS type inclusions to not exceed 2.0; the center segregation and center porosity of the slab do not exceed C1.5, and the equiaxed crystal ratio is above 15%.

[0023] In a first aspect, the present application provides a smelting method of 10CrNiCu ship steel, comprising the following steps:

[0024] After KR treatment, the molten iron is transferred into a converter for smelting to obtain converter steel liquid, wherein the iron-to-water ratio in the charge of the converter is not less than 0.80;

[0025] The molten steel from the converter is tapped into the LF refining furnace for deoxidation and alloying to obtain the first refined molten steel, wherein the tapping temperature of the molten steel from the converter meets 1680-1700°C;

[0026] transferring the first refined molten steel into an RH refining furnace for vacuum smelting to obtain a second refined molten steel;

[0027] The second refined molten steel is cast to obtain 10CrNiCu naval vessel steel, which includes the following components in mass percentage: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, 0.65wt%≤Cr≤0.75wt%; the rest are iron and other inevitable impurities.

[0028] The smelting method of 10CrNiCu naval vessel steel in the embodiment of the present application adopts the KR-BOF-LF refining + RH refining -CC continuous casting process route, and controls the parameters in the steel production process and the content of each element component, so that the inclusions A, B, C, and D of the steel plate material are controlled not to exceed 1.0, and the DS inclusions are not more than 2.0; the center segregation and center porosity of the slab do not exceed C1.5, and the equiaxed crystal ratio is above 15%.

[0029] Among them, KR stands for molten iron desulfurization station, BOF stands for converter, LF stands for refining furnace, RH stands for vacuum cycle degassing, and CC stands for continuous casting.

[0030] According to the smelting method of 10CrNiCu naval vessel steel provided in the embodiment of the present application, rare earth oxidation metallurgy is used to control inclusions, vacuum refining degassing treatment and continuous casting billet quality control segregation, and the KR-BOF-LF+RH-CC process route is used to produce continuous casting slabs with excellent surface and internal quality to meet the relatively stringent quality requirements of 10CRNICU products.

[0031] Firstly, the molten iron is KR desulfurized, and the S content of the molten iron added to the converter does not exceed 0.005%; secondly, the converter adopts a molten iron ratio of not less than 0.80, and the converter smelting ensures the hit rate of C, P and temperature endpoint, the P content does not exceed 0.010%, and the converter alloys Ni, Cr, Cu, etc. are adjusted in place; the production processes of using rare earth oxides to smelt high-cleanliness molten steel, continuous casting with low superheat stable casting and dynamic light reduction, etc.; the continuous casting slab is produced within C1.5, and the equiaxed crystal rate of the slab reaches 15%. The production process ensures the quality of 10CRNICU ship steel slabs, which provides a guarantee for product quality.

[0032] In the production and manufacturing scheme provided in this application, by rationally selecting the chemical composition and production process smelting, the mechanism of action of each low temperature and high toughness alloy component is as follows:

[0033] C: It is an essential element to ensure strength. It has a significant effect on improving the strength of steel through solid solution strengthening and precipitation strengthening, and also improves the hardenability of steel. However, the C content has a negative impact on the toughness and weldability of steel. Considering the cost and product quality, the C content is controlled at 0.07-0.11%.

[0034] Mn: It is an essential element to ensure the strength and toughness of steel. Mn is a good deoxidizer, but MnS inclusions have a great impact on the toughness of the material. At the same time, Mn is an element that is easy to segregate. Considering the product quality, the C content is controlled at 0.70-0.90%.

[0035] P: is an element that has a great adverse effect on low-temperature impact toughness. It segregates in the center of the ingot and aggregates at the grain boundaries, which damages the low-temperature toughness. The P content in the material smelted by the present invention is controlled to be no higher than 0.015%.

[0036] Cr, Ni, Cu: Not only can they improve the strength, hardness and seawater corrosion resistance of steel, but Ni can also increase hardenability, expand the austenite region, refine grains, and improve toughness. At the same time, it can inhibit surface thermal cracks caused by Cu content and promote the precipitation of Cu atomic clusters.

[0037] In some embodiments, when the molten iron is subjected to KR treatment, the temperature of the molten iron is not less than 1280° C., and after the molten iron is subjected to KR treatment, the S content does not exceed 0.005%, and the post-slag cleanliness is not less than 85%.

[0038] In some embodiments, Ni-Fe alloy and scrap steel are added during smelting in the converter, Cr and Cu alloys are added when the molten steel is tapped from the converter, and Ni, Cr, and Cu alloys are adjusted to above 85% of the target composition when the molten steel is tapped from the converter.

[0039] Ni-Fe alloy is added during smelting to adjust the composition according to the product composition, and scrap steel is added to adjust the thermal balance of converter smelting.

[0040] In some embodiments, slag blocking + slag retention operation is adopted when the molten steel in the converter is tapped, and the end point P does not exceed 0.012%.

[0041] Converter slag is an oxidizing slag. The final slag of converter smelting is not only highly oxidizing, but also brings smelting difficulties to subsequent refining operations (because refining requires reducing slag to deoxidize, desulfurize, remove inclusions, etc. to improve the cleanliness of molten steel); at the same time, the content of P, S, etc. in the slag is very high, and slag blocking operation is necessary for converter steelmaking. For high-grade steel grades with high requirements for P, S and other elements, slag retention operation is required to make up for the defects of slag blocking operation.

[0042] In some embodiments, in the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, the temperature during the transfer needs to meet 1620-1635°C.

[0043] The temperature during the transfer is in the range of 1620-1635℃, the main purpose of which is to maintain the temperature of the molten steel in the subsequent RH process smelting operation. Because if the molten steel temperature is not enough in the RH process, Al must be added to increase the temperature, resulting in the heat release of the reaction between Al and O to increase the temperature of the molten steel. At the same time, the reaction between Al and O will increase the inclusion of Al2O3 in the molten steel, which also wastes production costs. Secondly, the temperature of the molten steel in RH is too high, and the molten steel smelting time out of RH needs to be extended to reduce the temperature of the molten steel and ensure the temperature of the molten steel in continuous casting.

[0044] In some embodiments, in the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, the steel is circulated for 8 to 12 minutes at a vacuum degree of ≤100 Pa, and then 0.25 to 0.35 Kg / T of lanthanide rare earth alloy is added and circulated for 3 to 5 minutes.

[0045] Vacuum degree ≤100pa is a parameter to ensure RH process. Higher vacuum degree affects RH operation. Circulation time is 8-12min to ensure uniform composition of RH molten steel. Add 0.35Kg / T lanthanide rare earth alloy and circulate for 3-5min. Rare earth alloy is used to control inclusions in molten steel. 3-5min is required to ensure that the alloy is melted and evenly distributed in the molten steel.

[0046] According to the embodiment of the first aspect of the present application, in the step of casting the second refined molten steel, the casting speed is controlled at 1.0-1.3 m / min, the first cold strength crystallizer wide surface is controlled at 3800-4200 L / min, the crystallizer narrow surface is 550-650 L / min, and the second cold strength is 0.55-0.75 m 3 / t, adopts three-stage dynamic light pressing mode, and the three-stage pressing amount is 3.0-4.5mm.

[0047] Pouring speed, primary cooling (crystallizer cooling), secondary cooling (segment cooling), and light reduction reduction rate are key process parameters for continuous casting, ensuring that the surface of the cast continuous casting slab is free of crack defects and the internal quality segregation is good.

[0048] The smelting method in the embodiment of the present application may further include a rolling step, and the rolling step may be performed using process parameters in the prior art, which will not be described in detail in this application.

[0049] In the second aspect, an embodiment of the present application provides a 10CrNiCu naval vessel steel, including the following components in mass percentage: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, 0.65wt%≤Cr≤0.75wt%; the rest are iron and other inevitable impurities.

[0050] By controlling the content of each element component, 10CrNiCu ship and marine steel can obtain continuous casting slabs with excellent surface and internal quality to meet the more stringent quality requirements of 10CrNiCu products.

[0051] In some embodiments, the center segregation and center porosity of the slab of 10CrNiCu ship and marine steel do not exceed C1.5, and the equiaxed crystal ratio meets 15% or more.

[0052] Example

[0053] The following examples describe the disclosure of the present application in more detail, and these examples are for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present application are apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the instruments used in the examples are commercially available.

[0054] Example 1

[0055] This embodiment provides a smelting production method based on 10CrNiCu ship and marine steel, and the specific implementation process includes:

[0056] S1. Molten steel composition in the middle package: C: 0.09wt%, Si: 0.38wt%, Mn: 0.82wt%, P: 0.009wt%, S: 0.002wt%, Als: 0.026wt%, N: 0.0035wt%, Ti:

[0057] 0.0153wt%, Nb: 0.0187wt%, Ni: 0.65wt%, Cu: 0.62wt%, Cr: 0.712wt%, and the rest are iron and inevitable elements.

[0058] S2. Adopt KR-BOF-LF+RH-CC production process. KR hot metal S is 0.002%, and 182 tons of converter hot metal and 45 tons of scrap steel are added. The final temperature of converter steel tapping is 1695℃, the final P is 0.008%, and the C is 0.045%.

[0059] S3.LF makes reducing white slag, controls the slag basicity at 5.5, adjusts the molten steel composition and temperature, switches to RH vacuum degassing, switches to a temperature of 1625°C, and a vacuum degree lower than 100pa. After circulating for 9 minutes, the amount of rare earth added is 0.25Kg / T, and the circulation is continued for 4 minutes. The rare earth element content in the molten steel is 0.0012%, the [0] content is 0.0015%, and the [H] content is 1.2ppm.

[0060] S4. Casting speed 1.20m / min, casting superheat 16℃, dynamic soft pressure reduction 4.5mm for the ingot, first cold strength crystallizer wide side control 4000L / min, crystallizer narrow side 580L / min, second cold strength 0.65m 3 / t. The thickness of the ingot is 230mm, the center segregation of the ingot does not exceed C1.0, and the equiaxed grains are 16%.

[0061] S5. Molten steel inclusions: B1.0, C0.5, D1.0, Ds1.5, Figure 1 It is a low-magnification microscopic schematic diagram of the 10CrNiCu ship and marine steel of Example 1 of the present application.

[0062] Example 2

[0063] This embodiment provides a smelting and manufacturing method based on a 10CrNiCu ship and marine steel, and the specific implementation process includes:

[0064] S1. Molten steel composition in the middle package: C: 0.08wt%, Si: 0.428wt%, Mn: 0.85wt%, P: 0.0085wt%, S: 0.002wt%, Als: 0.032wt%, N: 0.0038wt%, Ti:

[0065] 0.0123wt%, Nb: 0.0217wt%, Ni: 0.67wt%, Cu: 0.65wt%, Cr: 0.742wt%, and the rest are iron and inevitable elements.

[0066] S2. Adopt KR-BOF-LF+RH-CC production process. KR hot metal S is 0.002%, and 185 tons of converter hot metal and 44 tons of scrap steel are added. The final temperature of converter steel tapping is 1695℃, the final P is 0.007%, and the C is 0.045%.

[0067] S3.LF makes reducing white slag, controls the slag basicity at 5.8, adjusts the molten steel composition and temperature, switches to RH vacuum degassing, switches to a temperature of 1625°C, a vacuum degree lower than 100pa, and after circulating for 10min, adds 0.30Kg / T of rare earth, and circulates for 3min. The rare earth element content in the molten steel is 0.0017%, the [0] content is 0.0010%, and the [H] content is 1.2ppm.

[0068] S4. Casting speed 1.25m / min, casting superheat 15℃, dynamic soft pressure reduction 4.5mm for casting, first cold strength crystallizer wide surface control 4100L / min, crystallizer narrow surface 580L / min, second cold strength specific water volume 0.72m 3 / t. The thickness of the ingot is 230 mm, the center segregation of the ingot is C0.5, and the equiaxed grains are 18%.

[0069] S5. Molten steel inclusions: B0.5, D1.0, Ds1.5

[0070] Example 3

[0071] This embodiment provides a smelting production method based on 10CrNiCu ship and marine steel, and the specific implementation process includes:

[0072] S1. Composition of molten steel in the middle package: C: 0.07wt%, Si: 0.42wt%, Mn: 0.75wt%, P: 0.008wt%, S: 0.002wt%, Als: 0.030wt%, N: 0.0035wt%, Ti: 0.0148wt%, Nb: 0.0165wt%, Ni: 0.59wt%, Cu: 0.55wt%, Cr: 0.735wt%. The rest are iron and unavoidable elements.

[0073] S2. Adopt KR-BOF-LF+RH-CC production process. KR hot metal S is 0.002%, and 183 tons of converter hot metal and 46 tons of scrap steel are added. The final temperature of converter steel tapping is 1685℃, the final P is 0.008%, and the C is 0.040%.

[0074] S3.LF makes reducing white slag, controls the slag basicity at 6.2, adjusts the molten steel composition and temperature, switches to RH vacuum degassing, switches to a temperature of 1630°C, a vacuum degree lower than 100pa, and after a 9-minute cycle, adds 0.32Kg / T of rare earth, cycles for 3 minutes, and the rare earth element content of the molten steel is 0.0020%, the [0] content is 0.0010%, and the [H] content is 1.2ppm.

[0075] S4. Casting speed 1.25m / min, casting superheat 15℃, dynamic soft pressure reduction 4.5mm for the billet, first cold strength crystallizer wide side control 3900L / min, crystallizer narrow side 580L / min, second cold strength 0.72m 3 / t. The thickness of the ingot is 230 mm, the center segregation of the ingot is C0.5, and the equiaxed grains are 20%.

[0076] S5. Molten steel inclusions: B0.5, D1.0, Ds1.5

[0077] Comparative Example 1

[0078] This comparative example provides a conventional high-quality 10CrNiCu marine steel smelting method, and the specific implementation process includes:

[0079] S1. Molten steel composition in the middle package: C: 0.07wt%, Si: 0.35wt%, Mn: 0.88wt%, P: 0.012wt%, S: 0.003wt%, Als: 0.026wt%, N: 0.0036wt%, Ti:

[0080] 0.0173wt%, Nb: 0.0207wt%, Ni: 0.67wt%, Cu: 0.65wt%, Cr: 0.702wt%, and the rest are iron and inevitable elements.

[0081] S2. Adopt KR-BOF-LF+RH-CC production process. KR hot metal S is 0.002%, and 172 tons of converter hot metal and 58 tons of scrap steel are added. The final temperature of converter steel tapping is 1685℃, the final P is 0.011%, and the C is 0.045%.

[0082] S3.LF makes reducing white slag, controls the slag basicity at 5.0, adjusts the molten steel composition and temperature, switches to RH vacuum degassing, the vacuum degree is lower than 100pa, and after circulating for 12 minutes, the [0] content is 0.0015%, and the [H] content is 1.2ppm.

[0083] S4. Casting speed 1.35m / min, casting superheat 25℃, dynamic soft pressure reduction 4.5mm for the ingot, first cold strength crystallizer wide side control 4200L / min, crystallizer narrow side 600L / min, second cold strength 0.75m 3 / t. The thickness of the ingot is 230 mm, the center segregation of the ingot is C2.5, and the equiaxed grains are 9%.

[0084] S5. Molten steel inclusions: A1.5, B1.5, C0.5, D2.5, Ds3.0, Figure 2 It is a low-magnification microscopic schematic diagram of the 10CrNiCu ship and marine steel of comparative example 1 of the present application.

[0085] Comparative Example 2

[0086] This comparative example provides a conventional high-quality 10CrNiCu marine steel smelting method, and the specific implementation process includes:

[0087] S1. Molten steel composition in the middle package: C: 0.085wt%, Si: 0.42wt%, Mn: 0.92wt%, P: 0.014wt%, S: 0.003wt%, Als: 0.0285wt%, N: 0.0041wt%, Ti:

[0088] 0.0163wt%, Nb: 0.0227wt%, Ni: 0.64wt%, Cu: 0.67wt%, Cr: 0.682wt%, and the rest are iron and inevitable elements.

[0089] S2. Adopt KR-BOF-RH-CC production process. KR hot metal S is 0.002%, and 175 tons of converter hot metal and 40 tons of scrap steel are added. The final temperature of converter steel tapping is 1705℃, the final P is 0.011%, and the C is 0.05%.

[0090] S3.RH vacuum degassing, vacuum degree is less than 100pa, RH oxygen blowing is 73m3, after circulation for 12min, the [0] content is 0.0022%, and the [H] content is 1.2ppm.

[0091] S4. Casting speed 1.40m / min, casting superheat 25℃, dynamic soft pressure reduction 4.5mm for the ingot, first cold strength crystallizer wide side control 4200L / min, crystallizer narrow side 600L / min, second cold strength 0.75m 3 / t. The thickness of the ingot is 230 mm, the center segregation of the ingot is C2.0, and the equiaxed grains are 10%.

[0092] S5. Molten steel inclusions: A1.5, B2.5, C1.5, D2.5, Ds3.0, Figure 3 It is a low-magnification microscopic schematic diagram of the 10CrNiCu ship and marine steel of comparative example 2 of the present application.

[0093] The test data of the embodiments and comparative examples are shown in Table 1:

[0094] Table 1 Test data

[0095]

[0096] See also Figure 1 As shown in Table 1, the inclusions of A, B, C, and D types of inclusions in the steel plate material prepared in the embodiment of the present application are controlled not to exceed 1.0; the center segregation and center porosity of the slab do not exceed C1.5, the equiaxed crystal ratio is above 15%, and the quality is good.

[0097] The above is only a specific implementation method of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of the present application.

Claims

1. A smelting method for 10CrNiCu ship steel, characterized in that: The steps include: After KR treatment, the molten iron is transferred into a converter for smelting to obtain converter steel liquid, wherein the iron-to-water ratio in the charge of the converter is not less than 0.80; The molten steel from the converter is tapped into the LF refining furnace for deoxidation and alloying to obtain the first refined molten steel, wherein the tapping temperature of the molten steel from the converter meets 1680-1700°C; transferring the first refined molten steel into an RH refining furnace for vacuum smelting to obtain a second refined molten steel; Casting the second refined molten steel to obtain 10CrNiCu naval vessel steel, wherein the 10CrNiCu naval vessel steel comprises the following components in percentage by mass: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, and 0.65wt%≤Cr≤0.75wt%; The rest is iron and other inevitable impurities.

2. The smelting method of 10CrNiCu ship steel according to claim 1, characterized in that: When the molten iron is subjected to KR treatment, the temperature of the molten iron is not less than 1280° C. After the molten iron is subjected to KR treatment, the S content does not exceed 0.005%, and the post-slag cleanliness is not less than 85%.

3. The smelting method of 10CrNiCu ship steel according to claim 1, characterized in that: During smelting in the converter, Ni, Fe alloy and scrap steel are added, Cr, Cu alloy are added when the converter molten steel is tapped, and Ni, Cr, Cu alloy are adjusted to above 85% of the target composition when the converter molten steel is tapped.

4. The smelting method of 10CrNiCu naval vessel steel according to claim 1 or 3, characterized in that: When the molten steel in the converter is tapped, slag blocking + slag retaining operation is adopted, and the end point P does not exceed 0.012%.

5. The smelting method of 10CrNiCu ship steel according to claim 1, characterized in that: In the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, the temperature during the transfer needs to meet 1620-1635°C.

6. The smelting method of 10CrNiCu ship steel according to claim 1, characterized in that: In the step of transferring the first refined molten steel into the RH refining furnace for vacuum smelting, the molten steel is circulated for 8 to 12 minutes at a vacuum degree of ≤100 Pa, and then 0.25 to 0.35 kg / T of lanthanide rare earth alloy is added and circulated for 3 to 5 minutes.

7. The smelting method of 10CrNiCu ship steel according to claim 1, characterized in that: In the step of casting the second refined molten steel, the casting speed is controlled at 1.1-1.3 m / min, the first cold strength crystallizer wide surface is controlled at 3800-4200 L / min, the narrow surface is 550-650 L / min, the second cold strength is 0.55-0.65 m 3 / t, adopts three-stage dynamic light pressing mode, and the three-stage pressing amount is 3.0-4.5mm.

8. A 10CrNiCu ship steel, characterized in that: The invention comprises the following components in percentage by mass: 0.07wt%≤C≤0.11wt%, 0.35wt%≤Si≤0.50wt%, 0.70wt%≤Mn≤0.90wt%, P≤0.015wt%, S≤0.003wt%, 0.018wt%≤Als≤0.035wt%, N≤0.0045wt%, Ti≤0.018wt%, 0.015wt%≤Nb≤0.025wt%, 0.50wt%≤Ni≤0.70wt%, 0.50wt%≤Cu≤0.70wt%, 0.65wt%≤Cr≤0.75wt%; The rest is iron and other inevitable impurities.

9. The 10CrNiCu ship and marine steel according to claim 8, characterized in that: The center segregation and center porosity of the slab of the 10CrNiCu ship and marine steel do not exceed C1.5, and the equiaxed crystal ratio meets 15% or more.

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