Method for reducing TiN inclusion defects on surface of Ti-containing ferritic stainless steel

Abstract

The invention discloses a method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel, which comprises the following steps: optimally controlling steelmaking components, refining furnace process parameters and continuous casting and coping process parameters, controlling the TiN product in the components in the refining process to be less than a constant NTiN, controlling the Al content of a refining furnace after Al adjustment to be 0.003-0.006%, and controlling the relative silicon return amount RSi after Al adjustment to be greater than or equal to 20%, the method comprises the following steps: controlling the weak stirring time to be greater than or equal to 20 minutes before a refining furnace is discharged from the furnace, controlling the standing time to be greater than or equal to 10 minutes after the weak stirring is finished, controlling the steel casting temperature during continuous casting to be LT + 40 DEG C to LT + 55 DEG C, and executing a full repair process with the grinding rate being greater than or equal to 2.0 percent on the first casting blank and the second casting blank of each casting time of continuous casting, so that the purity of the Ti-containing ferritic stainless steel is regulated and controlled, and the yield of the Ti-containing ferritic stainless steel is improved. According to the method, the phenomenon that a crystallizer'forms a fish 'in the pouring process of the molten steel of the Ti-containing ferritic stainless steel is reduced, the occurrence rate of TiN inclusion defects on the surface of the Ti-containing ferritic stainless steel is reduced from the source, and the yield of Ti-containing ferritic stainless steel products is remarkably increased.

Description

Technical Field

[0001] The invention belongs to the technical field of stainless steel production, and in particular relates to a method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel. Background Art

[0002] Ferritic stainless steel is a material with good corrosion resistance and oxidation resistance. It has the advantages of high strength, good processability, and weldability. At the same time, due to its low alloy composition and significant economic advantages, it is widely used in building panels, rail transportation, home appliances, kitchen and bathroom, and other fields.

[0003] Conventional ferritic stainless steels have high C and N content, resulting in poor weldability and intergranular corrosion resistance. Simply reducing C and N levels to improve intergranular corrosion resistance and weldability is costly and lacks industrial application value. Therefore, adding the stabilizing element Ti to ferritic stainless steels has become an important technical approach to addressing these performance weaknesses.

[0004] Ti has a strong affinity for elements such as C and N. Under suitable conditions, Ti-containing stainless steel preferentially forms Ti C and N compounds, thereby reducing the precipitation of C and N elements and Cr C and N compounds in the solid solution, thereby improving the material's welding performance and intergranular corrosion resistance. However, due to the high melting point of TiN (1900°C), as the temperature of the molten steel decreases during the continuous casting process, TiN in the Ti-stabilized stainless steel melt tends to precipitate with inclusions such as A12O3 or MgO·A12O3 as the core, and gathers at the meniscus, reacting not only with FeO in the protective slag component, but also with SiO2 to release nitrogen, stirring the molten steel and causing the local molten steel temperature in the crystallizer to drop to form solidified steel blocks, forming "fish" in the crystallizer, resulting in a large number of TiN inclusion defects on the surface of the final products such as stainless steel plates and thin plates, such as Figure 1 As shown in Figure 2. Based on statistical calculations from actual production lines, the incidence of TiN inclusion defects on the surface of finished Ti-containing ferritic stainless steel products is currently around 45%. Surface defects on stainless steel plates not only increase the amount of regrinding required and impact the product yield, but in severe cases can directly lead to product rejection and significant losses. Summary of the Invention

[0005] In order to solve the above technical problems existing in the prior art, the present invention provides a method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel, comprising:

[0006] (1) Optimize and control steelmaking composition

[0007] The TiN product in the refining process of Ti-containing ferritic stainless steel is controlled to be less than the constant N TiN , where the TiN product is calculated as shown in Equation 1, and the constant NTiN The calculation is shown in formula 2:

[0008] TiN product = ωt%Ti×ωt%N×104 Formula 1

[0009] N TiN =1.25×ωt%Gr+1.5×ωt%Ni+0.55×ωt%Mn+7 Equation 2

[0010] (2) Optimize and control refining furnace process parameters

[0011] (2.1) The Al content in the refining furnace is controlled to be 0.003-0.006% after Al adjustment, and the relative silicon content R after Al adjustment Si Controlled at ≥20%, where the relative silicon return amount R Si The calculation is shown in formula 3:

[0012] R Si =(ωt%Si after Al adjustment - ωt%Si before Al adjustment) / ωt%Si before Al adjustment Formula 3

[0013] (2.2) The weak stirring time before the refining furnace is taken out of the furnace is controlled to be ≥20min, and the calming time after the weak stirring is controlled to be ≥10min;

[0014] (3) Optimize and control continuous casting and grinding process parameters

[0015] (3.1) The pouring temperature during continuous casting is controlled at LT+40°C to LT+55°C, where LT is the theoretical liquidus temperature of Ti-containing ferritic stainless steel;

[0016] (3.2) The first and second ingots of each continuous casting run shall be fully repaired, and the repair rate shall be controlled to be ≥2.0%.

[0017] Furthermore, in the above method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel, in optimizing and controlling the process parameters of the refining furnace, if the R Si If it is lower than 20%, continue to adjust Al until R Si Not less than 20%.

[0018] The method of reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel of the present invention has the following advantages and beneficial effects:

[0019] The present invention adopts the technical means of optimizing and controlling the steelmaking composition, refining furnace process parameters, continuous casting and grinding process parameters, and controls the TiN product in the refining process composition to be less than the constant N TiN , the Al content after Al adjustment in the refining furnace is controlled to 0.003-0.006% and the relative silicon content after Al adjustment R SiThe purity of Ti-containing ferritic stainless steel is controlled at ≥20%, the weak stirring time before the refining furnace is discharged is controlled at ≥20 minutes, and the calming time after the weak stirring is controlled at ≥10 minutes, the pouring temperature of steel during continuous casting is controlled at LT+40℃~LT+55℃, and the first and second ingots of each continuous casting are subjected to a full repair process with a repair rate of ≥2.0%, thereby achieving the purity control of Ti-containing ferritic stainless steel, reducing the occurrence of "fishing" phenomenon in the crystallizer during the pouring of Ti-containing ferritic stainless steel, and fundamentally reducing the incidence of TiN inclusion defects on the surface of Ti-containing ferritic stainless steel, and significantly improving the yield rate of Ti-containing ferritic stainless steel products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is the morphology of TiN inclusion defects on the surface of Ti-containing ferritic stainless steel. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] The present invention aims to provide a method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel. By optimizing and controlling the steelmaking composition, refining furnace (LF furnace) process parameters, continuous casting and grinding process parameters, the purity of the Ti-containing ferritic stainless steel can be controlled, and the occurrence of "fishing" in the crystallizer during the pouring of molten steel of the Ti-containing ferritic stainless steel can be reduced, thereby fundamentally reducing the incidence of TiN inclusion defects on the surface of the Ti-containing ferritic stainless steel.

[0024] Specifically, the method of reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel of the present invention comprises:

[0025] (1) Optimize and control steelmaking composition

[0026] Reasonable control of the Ti and N content in the refining process is an effective way to reduce TiN inclusion defects on the surface of the finished product. Therefore, in the present invention, the TiN product in the refining process of Ti-containing ferritic stainless steel is controlled to be less than the constant N TiN , where the TiN product is calculated as shown in Equation 1, and the constant N TiN It is related to the material equilibrium phase structure and alloy element content. In the present invention, the constant N TiN The calculation is shown in formula 2:

[0027] TiN product = ωt%Ti×ωt%N×10 4 Formula 1

[0028] N TiN =1.25×ωt%Gr+1.5×ωt%Ni+0.55×ωt%Mn+7 Equation 2

[0029] (2) Optimize and control refining furnace process parameters

[0030] (2.1) TiN inclusion defects are closely related to the purity of molten steel. The higher the oxygen content of molten steel, the greater the possibility of TiN inclusion defects in the finished product. However, due to equipment and operation limitations, it is usually impossible to directly measure the oxygen content of molten steel in the refining furnace. It is necessary to adjust the amount of Al added to reduce the oxygen content of molten steel, and to reversely infer the oxygen content of molten steel by detecting the change in Si content in molten steel. Therefore, in the present invention, the oxygen content of the refining furnace is controlled by adjusting Al, including: controlling the Al content of the refining furnace to 0.003-0.006% after Al adjustment, and the relative silicon content R after Al adjustment. Si Controlled at ≥20%, if R Si If it is lower than 20%, continue to adjust Al until R Si Not less than 20%, wherein the relative amount of silicon back R Si The calculation is shown in formula 3 (unit: %):

[0031] R Si =(ωt%Si after Al adjustment - ωt%Si before Al adjustment) / ωt%Si before Al adjustment Formula 3

[0032] (2.2) To prevent TiN from precipitating from inclusions in the molten steel during subsequent continuous casting, it is necessary to increase the soft stirring and calming time in the refining furnace to allow the inclusions to fully float, thereby reducing the inclusion level during the continuous casting process. Therefore, in the present invention, the weak stirring time before the refining furnace is discharged is controlled to ≥20 minutes, and the calming time after the weak stirring is controlled to ≥10 minutes.

[0033] (3) Optimize and control continuous casting and grinding process parameters

[0034] The main reason for the occurrence of mold fish is that the temperature of the molten steel drops during the continuous casting process, and the TiN in the molten steel precipitates with inclusions as the core and gathers at the meniscus. Therefore, the occurrence of TiN fish can be reduced to a certain extent by increasing the steel pouring temperature during the continuous casting process. At the same time, due to the increase in the steel pouring temperature, the first and second billets of each casting are still prone to fish defects due to the large temperature drop, and they need to undergo full surface grinding. In summary, in the present invention, the steel pouring temperature during continuous casting is controlled to LT+40℃~LT+55℃, where LT is the theoretical liquidus temperature of Ti-containing ferritic stainless steel; the first and second billets of each casting in continuous casting are subjected to a full grinding process, and the grinding rate is controlled to be ≥2.0%.

[0035] The method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel of the present invention is described in detail below in combination with specific embodiments of the present invention and comparative examples of the prior art.

[0036] Example 1

[0037] The product smelting route of Example 1 of the present invention is molten iron-converter-AOD-LF-CCM. The specific implementation process of the method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel in Example 1 includes:

[0038] (1) Optimize and control steelmaking composition

[0039] The chemical composition of Ti-containing ferritic stainless steel entering the refining furnace is as follows by weight: C: 0.016%, N: 0.013%, Si: 0.32%, Mn: 1.72%, P: 0.028%, S: 0.003%, Cr: 11.27%, Ni: 0.75%. The constant N is calculated according to formula 2. TiN =23.16. To meet the requirements of formula 1, the upper limit of the Ti content ωt%Ti should be 0.178. Therefore, Ti is added to the molten steel fed into the refining furnace until the maximum Ti content in the molten steel is 0.178%. In Example 1, Ti is added to the molten steel fed into the refining furnace until the actual Ti content in the molten steel is 0.173%. Therefore, in Example 1, the actual TiN product = ωt%Ti×ωt%N×10 4 =0.173×0.013×10 4 =22.49, less than the constant N TiN =23.16.

[0040] (2) Optimize and control refining furnace process parameters

[0041] (2.1) The Al content in the refining furnace was adjusted to 0.004%. The Si content was measured to return from 0.32% to 0.39% after the adjustment. The relative silicon content R after the adjustment was calculated according to formula 3. Si It is 21.88%, which meets the requirement of not less than 20%, and no further adjustment of Al is made;

[0042] (2.2) The weak stirring time before the refining furnace is taken out of the furnace is 23 minutes, and the calming time after the weak stirring is 12 minutes.

[0043] (3) Optimize and control continuous casting and grinding process parameters

[0044] According to the specific steel type involved in Example 1, the theoretical liquidus temperature LT of the Ti-containing ferritic stainless steel can be obtained to be 1510°C. The pouring temperature during continuous casting is controlled to 1553°C, and the first and second ingots of the casting are fully repaired, with a repair rate of 2.3%.

[0045] The ingot prepared in Example 1 was subjected to subsequent hot rolling, annealing, pickling and other processes to produce a total of 7 hot-rolled coils of Ti-containing ferritic stainless steel, without any inclusion defects. That is, according to Example 1 of the present invention, the incidence of TiN-type inclusion defects on the surface of the finished Ti-containing ferritic stainless steel product was 0%.

[0046] Example 2

[0047] The product smelting route of Example 2 of the present invention is molten iron-converter-AOD-LF-CCM. The specific implementation process of the method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel in Example 2 includes:

[0048] (1) Optimize and control steelmaking composition

[0049] The chemical composition of Ti-containing ferritic stainless steel entering the refining furnace is as follows by weight: C: 0.024%, N: 0.017%, Si: 0.29%, Mn: 1.78%, P: 0.027%, S: 0.002%, Cr: 11.12%, Ni: 0.70%. The constant N is calculated according to formula 2. TiN =22.93. To meet the requirements of formula 1, the upper limit of the Ti content ωt%Ti should be 0.135. Therefore, Ti is added to the molten steel fed into the refining furnace until the maximum Ti content in the molten steel is 0.135%. In Example 2, Ti is added to the molten steel fed into the refining furnace until the actual Ti content in the molten steel is 0.13%. Therefore, in Example 2, the actual TiN product = ωt%Ti×ωt%N×10 4 =0.13×0.017×10 4 =22.1, less than the constant N TiN =22.93.

[0050] (2) Optimize and control refining furnace process parameters

[0051] (2.1) The Al content in the refining furnace was adjusted to 0.003%. The Si content was measured to return from 0.29% to 0.32% after the Al adjustment. The relative silicon content R after the Al adjustment was calculated according to formula 3.Si is 10.34%, due to the relative amount of silicon R Si If the Al content is lower than 20%, continue to adjust Al to 0.004%. At this time, the measured Si content returns to 0.35%. The relative silicon content R after Al adjustment is calculated according to formula 3. Si It is 20.69%, which meets the requirement of no less than 20%, and no further adjustment of Al is made;

[0052] (2.2) The weak stirring time before the refining furnace is taken out of the furnace is 25 minutes, and the calming time after the weak stirring is 12 minutes.

[0053] (3) Optimize and control continuous casting and grinding process parameters

[0054] According to the specific steel type involved in Example 2, the theoretical liquidus temperature LT of the Ti-containing ferritic stainless steel can be obtained to be 1510°C. The pouring temperature during continuous casting is controlled to 1555°C, and the first and second ingots of the casting are fully repaired, with a repair rate of 2.2%.

[0055] The ingot prepared in Example 2 was subjected to subsequent hot rolling, annealing, pickling and other processes to produce a total of 9 hot-rolled coils of Ti-containing ferritic stainless steel, without any inclusion defects. That is, according to Example 2 of the present invention, the incidence of TiN-type inclusion defects on the surface of the finished Ti-containing ferritic stainless steel product was 0%.

[0056] Comparative Example 1

[0057] The product smelting route of Comparative Example 1 of the prior art is molten iron - converter - AOD - LF - CCM. The chemical composition of the product entering the refining furnace is, by weight, C: 0.027%, N: 0.016%, Si: 0.33%, Mn: 1.69%, P: 0.025%, S: 0.002%, Cr: 11.25%, Ni: 0.74%, Ti: 0.178%, and Al: 0.001%. In Comparative Example 1, no additional control is performed on Ti, and the constant N is calculated according to Formula 2 of the present invention. TiN The TiN product is 23.10, and the TiN product calculated according to formula 1 of the present invention is 28.48. Obviously, the TiN product in comparative example 1 is much larger than that of N TiN .

[0058] In Comparative Example 1, Al content was not adjusted in the refining furnace and was maintained at 0.001%. The weak stirring time before the refining furnace was removed from the furnace was 19 minutes, and the calming time after the weak stirring was 8 minutes. Based on the specific steel type involved in Comparative Example 1, the theoretical liquidus temperature LT of the Ti-containing ferritic stainless steel was 1510°C, the pouring temperature during continuous casting was 1545°C, and the ingot was not ground.

[0059] The ingots prepared in Comparative Example 1 were subjected to subsequent hot rolling, annealing, pickling and other processes to produce a total of 8 hot-rolled coils of Ti-containing ferritic stainless steel, of which 6 were scrapped due to inclusion defects. That is, through the implementation of Comparative Example 1, the incidence rate of TiN inclusion defects on the surface of the finished Ti-containing ferritic stainless steel products was 75%.

[0060] Comparative Example 2

[0061] The product smelting route of Comparative Example 2 of the prior art is molten iron - converter - AOD - LF - CCM. The chemical composition of the product entering the refining furnace is, by weight, C: 0.019%, N: 0.018%, Si: 0.32%, Mn: 1.76%, P: 0.026%, S: 0.002%, Cr: 11.31%, Ni: 0.72%, Ti: 0.12%, and Al: 0.001%. In Comparative Example 2, no additional control is performed on Ti, and the constant N is calculated according to Formula 2 of the present invention. TiN The TiN product is 23.18, and the TiN product calculated according to formula 1 of the present invention is 21.6. The TiN product in comparative example 2 is less than N TiN .

[0062] In Comparative Example 2, Al content was not adjusted in the refining furnace, and the Al content was maintained at 0.001%. The weak stirring time before the refining furnace was removed from the furnace was 21 minutes, and the calming time after the weak stirring was 11 minutes. According to the specific steel type involved in Comparative Example 2, the theoretical liquidus temperature LT of the Ti-containing ferritic stainless steel was 1510°C, the pouring temperature during continuous casting was 1555°C, and the ingot was not ground.

[0063] The ingots prepared in Comparative Example 2 were subjected to subsequent hot rolling, annealing, pickling and other processes to produce a total of 8 hot-rolled coils of Ti-containing ferritic stainless steel, of which 3 coils were scrapped due to inclusion defects. That is, through the implementation of Comparative Example 2, the incidence rate of TiN inclusion defects on the surface of the finished Ti-containing ferritic stainless steel products was 37.5%.

[0064] Comparative Example 3

[0065] The product smelting route of Comparative Example 3 of the prior art is molten iron - converter - AOD - LF - CCM. The chemical composition of the product entering the refining furnace is as follows by weight: C: 0.016%, N: 0.015%, Si: 0.31%, Mn: 1.75%, P: 0.023%, S: 0.002%, Cr: 11.17%, Ni: 0.74%, Ti: 0.125%. In Comparative Example 3, no additional control is performed on Ti, and the constant N is calculated according to Formula 2 of the present invention. TiN is 23.03, and the TiN product calculated according to formula 1 of the present invention is 18.75. In comparative example 3, the TiN product is less than N TiN .

[0066] In comparative example 3, Al was adjusted to 0.003% in the refining furnace. After the adjustment, the Si content was measured to be back to 0.39%. The relative silicon content R after the adjustment was calculated according to formula 3 of the present invention. Si It is 25.81%, which is greater than 20%.

[0067] In Comparative Example 3, the weak stirring time before the refining furnace is discharged is 16 minutes, and the calming time after the weak stirring is 8 minutes. According to the specific steel type involved in Comparative Example 3, the theoretical liquidus temperature LT of the Ti-containing ferritic stainless steel can be obtained to be 1510°C, the pouring temperature during continuous casting is 1554°C, and the ingot is not ground.

[0068] The ingots prepared in Comparative Example 3 were subjected to subsequent hot rolling, annealing, pickling and other processes to produce a total of 9 hot-rolled coils of Ti-containing ferritic stainless steel, of which 2 coils were scrapped due to inclusion defects. That is, through the implementation of Comparative Example 3, the incidence rate of TiN inclusion defects on the surface of the finished Ti-containing ferritic stainless steel products was 22.22%.

[0069] The following table summarizes the process parameters and the incidence of surface TiN inclusion defects of Examples 1-2 of the present invention and Comparative Examples 1-3 of the prior art:

[0070] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 TiN product 22.49 22.1 28.48 21.6 18.75 <![CDATA[N TiN ]]> 23.16 22.93 23.10 23.18 23.03 Al content after Al adjustment / % 0.004 0.004 0.001(not adjusted) 0.001(not adjusted) 0.003 <![CDATA[Relative return silicon quantity R after adjusting Al Si / %]]> 21.88 20.69 0 0 25.81 Weak stirring time / min 23 25 19 21 16 Sedation time / min 12 12 8 11 8 Steel pouring temperature / ℃ LT+43℃ LT+45℃ LT+35℃ LT+45℃ LT+44℃ Grinding rate / % 2.3 2.2 0 0 0 Defect incidence / % 0 0 75 37.5 22.22

[0071] In summary, the method of reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel of the present invention adopts the technical means of optimizing and controlling steelmaking composition, refining furnace process parameters, continuous casting and grinding process parameters, and controls the TiN product in the refining process composition to be less than the constant N TiN , the Al content after Al adjustment in the refining furnace is controlled to 0.003-0.006% and the relative silicon content after Al adjustment R Si The purity of the Ti-containing ferritic stainless steel is controlled at ≥20%, the weak stirring time before the refining furnace is discharged is controlled at ≥20 minutes, and the calming time after the weak stirring is controlled at ≥10 minutes. The pouring temperature of the steel during continuous casting is controlled at LT+40°C to LT+55°C. In addition, a full repair process with a repair rate of ≥2.0% is performed on the first and second ingots of each continuous casting. This achieves purity control of the Ti-containing ferritic stainless steel and reduces the occurrence of "fishing" in the crystallizer during the pouring of the Ti-containing ferritic stainless steel. As a result, the incidence rate of TiN inclusion defects on the surface of the Ti-containing ferritic stainless steel is reduced from 45% in the prior art to 0%, significantly improving the yield rate of the Ti-containing ferritic stainless steel products.

[0072] It should be noted that, unless otherwise specified, the noun terms herein have the meanings commonly understood by those skilled in the art. Moreover, when a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple range description features are provided, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0073] It should also be noted that, in this article, the term "comprise" or any other variation thereof is intended to cover non-exclusive inclusion, so that an article or device that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements that are inherent to such article or device.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the present invention.

Claims

1. A method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel, characterized in that: include: (1) Optimize and control steelmaking composition The TiN product in the refining process of Ti-containing ferritic stainless steel is controlled to be less than the constant N TiN , where the TiN product is calculated as shown in Equation 1, and the constant N TiN The calculation is shown in formula 2: TiN product = ωt%Ti×ωt%N×10 4 Formula 1 N TiN = 1.25 × ωt% Gr + 1.5 × ωt% Ni + 0.55 × ωt% Mn + 7 Equation 2 (2) Optimize and control refining furnace process parameters (2.1) The Al content in the refining furnace is controlled to be 0.003-0.006% after Al adjustment, and the relative silicon content R after Al adjustment Si Controlled at ≥20%, where the relative silicon return amount R Si The calculation is shown in formula 3: R Si =(ωt%Si after Al adjustment - ωt%Si before Al adjustment) / ωt%Si before Al adjustment Formula 3 (2.2) The weak stirring time before the refining furnace is taken out of the furnace is controlled to be ≥20min, and the calming time after the weak stirring is controlled to be ≥10min; (3) Optimize and control continuous casting and grinding process parameters (3.1) The pouring temperature during continuous casting is controlled at LT+40°C to LT+55°C, where LT is the theoretical liquidus temperature of Ti-containing ferritic stainless steel; (3.2) The first and second ingots of each continuous casting run shall be fully repaired, and the repair rate shall be controlled to be ≥2.0%.

2. The method for reducing TiN inclusion defects on the surface of Ti-containing ferritic stainless steel according to claim 1, characterized in that: In optimizing and controlling the process parameters of the refining furnace, if the R Si If it is lower than 20%, continue to adjust Al until R Si Not less than 20%.

Images