A method for producing a steel for enamel

Abstract

The application relates to a preparation method of enamel steel, and belongs to the technical field of steel preparation; the method comprises the following steps: carrying out KR pretreatment on molten iron; carrying out converter smelting on the KR pretreated molten iron to obtain converter molten steel; carrying out LF refining treatment and VD refining treatment on the converter molten steel, wherein the VD refining treatment comprises first refining treatment and second refining treatment, the bottom blowing flow of the first refining treatment is greater than that of the second refining treatment; carrying out titanium and sulfur adjustment on the molten steel after the VD refining treatment is broken, so that the content of titanium and sulfur elements reaches a target value, and then carrying out soft blowing and continuous casting to obtain the enamel steel; the enamel steel is prepared by adopting a KR-BOF-LF-VD process, a new preparation path of the enamel steel is provided, and the problem that the production mode of the enamel steel is relatively single at present is solved.

Description

Technical Field

[0001] This application relates to the field of steel preparation technology, and in particular to a method for preparing enamel steel. Background Technology

[0002] Applying enamel enamel to the surface of steel plates prevents rusting, prevents the formation of an oxide layer when heated, and resists corrosion from various liquids. Enameled products are not only safe and non-toxic but also easy to clean. Currently, the mainstream production method for enamel steel is relatively simple, employing the KR-BOF-LF-RH process. Summary of the Invention

[0003] This application provides a method for preparing enamel steel, thereby providing a new preparation path for enamel steel and solving the problem that the current production methods for enamel steel are relatively limited.

[0004] This application provides a method for preparing enamel steel, the method comprising:

[0005] KR pretreatment was performed on the molten iron;

[0006] The molten iron after KR pretreatment is smelted in a converter to obtain converter steel.

[0007] The molten steel from the converter is subjected to LF refining and VD refining. The VD refining includes a first refining and a second refining. The bottom blowing flow rate of the first refining is greater than the bottom blowing flow rate of the second refining.

[0008] The molten steel after the VD refining process is subjected to titanium and sulfur adjustment to ensure that the content of titanium and sulfur elements reaches the target value. Then, it is subjected to soft blowing and continuous casting to obtain enamel steel.

[0009] As an optional implementation, the bottom-blowing flow rate of the first refining process is 150–200 NL / min; and / or

[0010] The first refining process takes 12–14 minutes; and / or

[0011] The bottom-blowing flow rate for the second refining process is 30–50 NL / min; and / or

[0012] The second refining process takes 4 to 6 minutes.

[0013] As an optional implementation, the sulfur content of the molten iron after KR pretreatment is 0.04% to 0.085% by mass fraction.

[0014] As an optional implementation, the phosphorus content of the molten steel in the converter is <0.010% and the carbon content is 0.03% to 0.08% by mass fraction.

[0015] As an optional implementation, the temperature of the molten steel in the converter is 1630–1650°C.

[0016] As an optional implementation, the method includes: adding quicklime to the slag washed from the converter smelting; and / or

[0017] Aluminum particles are added to the slag surface after the converter smelting.

[0018] As an optional implementation, the amount of quicklime added is 900–1100 kg / t; and / or

[0019] The amount of aluminum granules added is 90-110 kg / t.

[0020] As an optional implementation, ferrotitanium is added to the molten steel in the converter during the LF refining process; and / or

[0021] The amount of ferrotitanium added is 600-700 kg / t.

[0022] As an optional implementation, the sum of the contents of MnO and FeO in the final slag of the LF refining treatment is not greater than 1% by mass fraction.

[0023] As an optional implementation, the flow rate of the soft blower is 30-50 NL / min.

[0024] The technical solutions provided in this application have the following advantages compared with the prior art:

[0025] The method provided in this application, which uses the KR-BOF-LF-VD process to prepare enamel steel, offers a new preparation path for enamel steel and solves the problem of the relatively singular production method of enamel steel at present. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1A flowchart illustrating the method provided in an embodiment of this application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0031] like Figure 1 As shown in the embodiment of this application, a method for preparing enamel steel is provided, the method comprising:

[0032] S1. Perform KR pretreatment on molten iron; it should be noted that KR pretreatment does not involve desulfurization, but only pre-slag removal.

[0033] The purpose of pre-slag removal is to increase the sulfur content in the molten iron and reduce the use of sulfur wire in the VD process.

[0034] In some embodiments, the sulfur content of the molten iron after KR pretreatment is 0.04% to 0.085% by mass fraction.

[0035] The sulfur content in the molten iron after KR pretreatment is controlled to be between 0.04% and 0.085% to ensure that the sulfur content in the molten iron is within a reasonable level for the process. If the content is too high, the sulfur content in the VD process will exceed the limit. If the content is too low, the sulfur content in the VD process will be too high, increasing the cost.

[0036] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel;

[0037] In some embodiments, the phosphorus content of the molten steel in the converter is <0.010% and the carbon content is 0.03% to 0.08% by mass fraction, and the temperature of the molten steel in the converter is 1630 to 1650°C.

[0038] Controlling the phosphorus content in the molten steel in the converter to <0.010% and the carbon content to 0.03% to 0.08% is to meet the steel composition requirements. If the content is too high, the adverse effect is that the composition is out of specification; if it is too low, the adverse effect is that the composition is out of specification.

[0039] Controlling the temperature of molten steel in the converter to 1630-1650℃ is to ensure that the temperature of molten steel entering the LF furnace is at a reasonable level. If the temperature is too high or too low, it will have adverse effects on the stability and cycle of LF furnace production.

[0040] In some embodiments, quicklime is added to the slag wash after converter smelting; aluminum particles are added to the slag surface after converter smelting. The amount of quicklime added is 900-1100 kg / t; the amount of aluminum particles added is 90-110 kg / t.

[0041] The purpose of quicklime is to prevent oxidation and desulfurization of molten steel by submerged arc slag formation. The addition amount of quicklime is controlled at 600-700 kg / t to reduce desulfurization in slag washing furnace. If the addition amount is too large, the adverse effect is excessive desulfurization in slag washing. If the addition amount is too small, the adverse effect is that the molten steel will be exposed and oxidized.

[0042] The function of aluminum granules is deoxidation and desulfurization. The amount of aluminum granules added is controlled at 90-110 kg / t to remove oxygen from the molten steel and prevent excessive desulfurization. If the amount added is too large, the adverse effect is excessive desulfurization, and if it is too small, the adverse effect is that the molten steel has strong oxidizing properties and the steel quality will be problematic.

[0043] It should be noted that after the converter smelting is completed, the normal turnover package will have its siphon sand added twice to ensure that the ladle opens automatically.

[0044] S3. The converter steel is subjected to LF refining and VD refining treatment. The VD refining treatment includes a first refining treatment and a second refining treatment. The bottom blowing flow rate of the first refining treatment is greater than the bottom blowing flow rate of the second refining treatment.

[0045] In some embodiments, ferrotitanium is added to the molten steel in the LF refining process; the amount of ferrotitanium added is 600-700 kg / t. It should be noted that the ferrotitanium is added in the later stage of the LF refining process, specifically after 40 minutes of LF refining, in two batches.

[0046] The role of ferrotitanium is to adjust the titanium content in molten steel. The addition of quicklime is controlled at 600-700 kg / t to reduce desulfurization in the LF furnace. If the addition amount is too high, the adverse effect is excessive desulfurization in the LF furnace. If it is too low, the adverse effect is that the molten steel is exposed to oxidation and the heating efficiency is low.

[0047] In some embodiments, the sum of the contents of MnO and FeO in the final slag of the LF refining process is not greater than 1% by mass fraction.

[0048] Controlling the sum of MnO and FeO content to no more than 1% is to ensure that the oxidizing properties of molten steel are within the required process level. An excessively high value would result in strong oxidizing properties of the molten steel, making it impossible to guarantee the quality of the steel.

[0049] Specifically, in this embodiment, 600-700 kg of high-titanium iron is added in two batches during the later stage of LF refining, and the temperature is increased after the addition to promote the melting of the titanium iron.

[0050] In some embodiments, the bottom-blowing flow rate of the first refining process is 150-200 NL / min; the time of the first refining process is 12-14 min; the bottom-blowing flow rate of the second refining process is 30-50 NL / min; and the time of the second refining process is 4-6 min.

[0051] The bottom blowing flow rate of the first refining process is controlled at 150-200 NL / min and the time is 12-14 min in order to remove hydrogen and nitrogen elements from the molten steel. If the value is too large, the adverse effect is a large drop in the temperature of the molten steel; if the value is too small, the adverse effect is that the hydrogen and nitrogen elements are not in harmony.

[0052] The bottom blowing flow rate of the first refining process is controlled at 30-50 NL / min and the time is 4-6 min in order to promote the floating of inclusions. If the value is too large or too small, the adverse effect is that it will not promote the floating of inclusions.

[0053] Specifically, in this embodiment, the VD refining process adopts the "13+5 mode", with a total deep vacuum time of 18 minutes, a high argon flow rate of 150-200 NL / min for the first 13 minutes, and a low argon flow rate of 30-50 NL / min for the last 5 minutes.

[0054] S4. The molten steel after the VD refining process is subjected to titanium and sulfur adjustment to ensure that the content of titanium and sulfur elements reaches the target value. Then, soft blowing and continuous casting are performed to obtain enamel steel.

[0055] Specifically, in this embodiment, the molten steel after the VD refining process is sampled, and titanium and sulfur wires are added according to the elemental content of the sample to adjust the titanium and sulfur content to the target values. Then, soft blowing is performed for 15 minutes, observing the ladle surface. The soft blowing flow rate is controlled at 30-50 NL / min, adjusted according to the actual effect.

[0056] In some embodiments, the flow rate of the soft blower is 30–50 NL / min.

[0057] The flow rate of soft blowing is controlled at 30-50 NL / min to promote the floating of inclusions. If the value is too high or too low, the adverse effect is that it will not promote the floating of inclusions.

[0058] The enamel steel prepared by the method provided in this application has similar properties to the enamel steel prepared by the prior art. It can be seen that the method provided in this application can successfully prepare enamel steel, providing a new preparation method for enamel steel.

[0059] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0060] Example 1

[0061] A method for preparing enamel steel, the method comprising:

[0062] S1. The molten iron undergoes KR pretreatment; KR pretreatment does not include desulfurization, only pre-slag removal. The sulfur content at the end of KR is 0.081%.

[0063] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel; the final phosphorus content of the converter is 0.00784%, the final carbon content of the converter is 0.034%, and the final temperature of the converter is 1645℃; 992 kg of fine lime and 100 kg of aluminum particles are added to the slag washing material after the furnace; normal turnover ladle, sand is added twice to guide sand, and the ladle opens automatically.

[0064] S3. The molten steel from the converter is subjected to LF refining and VD refining treatment; the sum of the final slag (MnO+FeO) after LF refining treatment is 0.97%, and the VD refining treatment adopts the "13+5 mode", with a total deep vacuum time of 18 minutes, a large argon flow rate of 150NL / min for the first 13 minutes, and a small argon flow rate of 30NL / min for the last 5 minutes.

[0065] After the S4.VD refining process, a process sample was taken, and the titanium wire was finely adjusted to 100m and the sulfur wire to 150m to bring the elemental composition to the target range. Then, soft blowing and continuous casting were carried out. The soft blowing time was 15min and the soft blowing flow rate was controlled at 30NL / min to obtain enamel steel.

[0066] Example 2

[0067] A method for preparing enamel steel, the method comprising:

[0068] S1. The molten iron undergoes KR pretreatment; KR pretreatment does not include desulfurization, only pre-slag removal. The sulfur content at the end of KR is 0.057%.

[0069] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel; the final phosphorus content of the converter is 0.00899%, the final carbon content of the converter is 0.030%, and the final temperature of the converter is 1650℃; 994 kg of small-particle lime and 100 kg of aluminum particles are added to the slag washing material after the furnace; normal turnover ladle, sand is added twice to guide sand, and the ladle opens automatically.

[0070] S3. The converter steel is subjected to LF refining and VD refining treatment; the sum of the final slag (MnO+FeO) after LF refining is 0.39%, and the VD refining treatment adopts the "13+5 mode", with a total deep vacuum time of 18 minutes, a large argon flow rate of 200NL / min for the first 13 minutes, and a small argon flow rate of 50NL / min for the last 5 minutes.

[0071] After the S4.VD refining process, a process sample was taken, and the titanium wire was finely adjusted to 50m and the sulfur wire to 250m to bring the elemental composition to the target range. Then, soft blowing and continuous casting were carried out. The soft blowing time was 15min and the soft blowing flow rate was controlled at 32NL / min to obtain enamel steel.

[0072] Example 3

[0073] A method for preparing enamel steel, the method comprising:

[0074] S1. The molten iron undergoes KR pretreatment; KR pretreatment does not include desulfurization, only pre-slag removal. The sulfur content at the end of KR is 0.081%.

[0075] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel; the final phosphorus content of the converter is 0.00784%, the final carbon content of the converter is 0.034%, and the final temperature of the converter is 1645℃; 992 kg of fine lime and 100 kg of aluminum particles are added to the slag washing material after the furnace; normal turnover ladle, sand is added twice to guide sand, and the ladle opens automatically.

[0076] S3. The converter steel is subjected to LF refining and VD refining. The sum of the final slag (MnO+FeO) after LF refining is 0.97%. The VD refining adopts the "13+5 mode", with a total deep vacuum time of 18 minutes. The first 13 minutes have a large argon flow rate of 120NL / min, and the last 5 minutes have a small argon flow rate of 20NL / min.

[0077] After the S4.VD refining process, a process sample was taken, and the titanium wire was finely adjusted to 100m and the sulfur wire to 150m to bring the elemental composition to the target range. Then, soft blowing and continuous casting were carried out. The soft blowing time was 15min and the soft blowing flow rate was controlled at 30NL / min to obtain enamel steel.

[0078] This process carries the risk of excessive inclusions and non-compliance with flaw detection in enamel steel.

[0079] Example 4

[0080] A method for preparing enamel steel, the method comprising:

[0081] S1. The molten iron undergoes KR pretreatment; KR pretreatment does not include desulfurization, only pre-slag removal. The sulfur content at the end of KR is 0.081%.

[0082] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel; the final phosphorus content of the converter is 0.00784%, the final carbon content of the converter is 0.034%, and the final temperature of the converter is 1645℃; 992 kg of fine lime and 100 kg of aluminum particles are added to the slag washing material after the furnace; normal turnover ladle, sand is added twice to guide sand, and the ladle opens automatically.

[0083] S3. The converter steel is subjected to LF refining and VD refining treatment; the sum of the final slag (MnO+FeO) after LF refining treatment is 0.97%, and the VD refining treatment adopts the "13+5 mode" with a total deep vacuum time of 18 minutes, a large argon flow rate of 230NL / min for the first 13 minutes, and a small argon flow rate of 80NL / min for the last 5 minutes.

[0084] After the S4.VD refining process, a process sample was taken, and the titanium wire was finely adjusted to 100m and the sulfur wire to 150m to bring the elemental composition to the target range. Then, soft blowing and continuous casting were carried out. The soft blowing time was 15min and the soft blowing flow rate was controlled at 30NL / min to obtain enamel steel.

[0085] This process carries the risk of excessive inclusions and non-compliance with flaw detection in enamel steel.

[0086] Example 5

[0087] A method for preparing enamel steel, the method comprising:

[0088] S1. The molten iron undergoes KR pretreatment; KR pretreatment does not include desulfurization, only pre-slag removal. The sulfur content at the end of KR is 0.081%.

[0089] S2. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel; the final phosphorus content of the converter is 0.00784%, the final carbon content of the converter is 0.034%, and the final temperature of the converter is 1645℃; 992 kg of fine lime and 100 kg of aluminum particles are added to the slag washing material after the furnace; normal turnover ladle, sand is added twice to guide sand, and the ladle opens automatically.

[0090] S3. The converter steel is subjected to LF refining and VD refining treatment; the sum of the final slag (MnO+FeO) after LF refining treatment is 1.3%, and the VD refining treatment adopts the "13+5 mode" with a total deep vacuum time of 18 minutes, a large argon flow rate of 150NL / min for the first 13 minutes, and a small argon flow rate of 30NL / min for the last 5 minutes.

[0091] After the S4.VD refining process, a process sample was taken, and the titanium wire was finely adjusted to 100m and the sulfur wire to 150m to bring the elemental composition to the target range. Then, soft blowing and continuous casting were carried out. The soft blowing time was 15min and the soft blowing flow rate was controlled at 30NL / min to obtain enamel steel.

[0092] This process carries the risk of excessive inclusions and non-compliance with flaw detection in enamel steel.

[0093] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0094] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the orientation shown in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to."

[0095] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this document, "and / or" describes the association between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0096] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing enamel steel, characterized in that, The method includes: The molten iron is subjected to KR pretreatment, which does not involve desulfurization but only pre-slag removal. The sulfur content of the molten iron after KR pretreatment is 0.04%~0.085% by mass fraction. The molten iron after KR pretreatment is smelted in a converter to obtain converter steel. The molten steel from the converter is subjected to LF refining and VD refining. The VD refining process includes a first refining process and a second refining process. The bottom blowing flow rate of the first refining process is 150~200 NL / min, and the time of the first refining process is 12~14 min. The bottom blowing flow rate of the second refining process is 30~50 NL / min, and the time of the second refining process is 4~6 min. The molten steel after the VD refining process is subjected to titanium and sulfur adjustment to ensure that the content of titanium and sulfur elements reaches the target value. Then, it is subjected to soft blowing and continuous casting to obtain enamel steel. In the LF refining process, ferrotitanium is added to the molten steel in the converter; the timing of the addition of ferrotitanium is 40 minutes after the LF refining process, and the amount of ferrotitanium added is 600~700 kg / t. By mass fraction, the sum of the contents of MnO and FeO in the final slag of the LF refining process is not greater than 1%; The flow rate of the soft blower is 30~50 NL / min.

2. The method for preparing enamel steel according to claim 1, characterized in that, The phosphorus content in the molten steel from the converter is less than 0.010% and the carbon content is 0.03% to 0.08% by mass fraction.

3. The method for preparing enamel steel according to claim 1, characterized in that, The temperature of the molten steel in the converter is 1630~1650℃.

4. The method for preparing enamel steel according to claim 1, characterized in that, The method includes: adding quicklime to the slag washed material after converter smelting; and / or Aluminum particles are added to the slag surface after the converter smelting.

5. The method for preparing enamel steel according to claim 4, characterized in that, The amount of quicklime added is 900~1100 kg / t; and / or The amount of aluminum granules added is 90~110 kg / t.

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