JPH11156503A - Production method of ferrite system stainless steel plate with no rolling surface defect and with excellent ridgingness, and wire for b adding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stainless steel plate without rolling surface defects and with excellent ridging property by inserting a B adding wire, wherein the material including B is wrapped with a coating material, in a center unsolified portion in a mold being continuous cast, fusion solvent it, and adding a specific volume of B to the center part of a cast piece. SOLUTION: A mother steel is composed of, at weight percentage, 0.08% or less C, 0.05-1.0% Si, 0.05-1.0% Mn, 0.001-0.2% acid soluble aluminum, 0.06% or less N, 10-23% Cr and Fe which substantially constitutes the residue. The mother molten steel is cast continuously, and the B adding wire is inserted in the unsolified part of the mother molten steel located in the center of the mold, and is melted and is dissolved, and 30-300 ppm of B is added. The position where B is added is set to be a central part which is deeper than the position which 10-35% of total thickness from the surface of the cast piece. An outer cover 1 of the B adding wire is the austenitic stainless steel, of which the melting point is lower than that of the mother molten steel, and a core 2 of the central part is a mixture of one kind or more of B containing alloy, ferro boron, Fe carbonic boron, and Cr carbonic boron.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a ferritic stainless steel sheet represented by SUS430 steel, and more particularly, to a method for producing a ferritic stainless steel sheet having no rolled surface eaves and excellent ridging properties, and the addition of B used therein. It relates to a wire for use.

[0002]

2. Description of the Related Art Ferritic stainless steel sheets are widely used for kitchen appliances and other household goods, building materials, home appliances, and automobile parts, because they can easily realize high smoothness by clear color tone and cold rolling. . However, cold rolling of ferritic stainless steel sheet causes RMS
It has been recognized that irregularities of 1 μm or less are generated in (root mean square roughness) and the smoothness is impaired. In addition, it has been recognized that when press forming or tensile processing is applied, wrinkles of unevenness are generated parallel to the rolling direction, and in extreme cases, they are deformed into a corrugated sheet shape. These irregularities are generally called ridging and are considered to be fatal defects unique to ferritic stainless steel sheets. Ridging impairs color tone and smoothness, making it difficult to perform a polishing treatment to recover the color tone and smoothness. In addition, depending on parts, it may affect functional problems such as lowering adhesion.

Although the cause of ridging is not always clear, it is generally considered as follows. That is, one coarse crystal grain at the time of casting is subjected to working heat treatment such as hot rolling or annealing to be recrystallized and refined. However, since most of the refined grains have almost the same crystal orientation, it is necessary to regard them as forming pseudo-coarse grains corresponding to the original coarse grains in terms of texture. Is done. Therefore, the deformation behavior is the same as that of the ultra-coarse-grained thin steel sheet, and the difference in the deformation behavior of each pseudo-coarse-grained grain appears on the surface as unevenness.

In the conventional ridging countermeasures, concrete measures have been generally implemented based on the following three types of ideas based on this estimation mechanism. Of course, in many cases, the effects have been increased by superimposing each of the components, instead of implementing them alone. (1) Refinement of solidified crystal grains that are the source of pseudo coarse grains (2) Texture randomization of pseudo coarse grains (3) Decomposition of pseudo coarse grains The idea of (1) is pseudo This is related to the refinement of coarse grains. For example, as disclosed in Japanese Patent Application Laid-Open No. 50-123294, electromagnetic stirring aimed at equiaxed columnar crystals, and refinement of solidified crystal grains were aimed at. Rapid solidification by introducing solidified crystal nuclei or lowering the casting temperature has been implemented as a specific measure. According to the idea of (2), JP-A-57-70
As disclosed in Japanese Patent Publication No. 234, the recrystallization is promoted in the manufacturing process, and the hot rolling temperature (heating, finishing, winding temperature, etc.), the rolling reduction, the annealing temperature, etc. are adjusted to be repeated a plurality of times. Use of intergranular precipitates and γ phase to add widening deformation in addition to elongation deformation during hot rolling, adding an intermediate annealing step during cold rolling to increase the number of cold rolling recrystallizations And optimization of hot rolling lubrication. In (3),
As disclosed in JP-A-6-81036,
A component change intended to introduce a transformation and a special heat process have been proposed.

[0005]

However, the method (1) has an advantage in that it can be dealt with only at the time of casting and has little interference with the subsequent steps. There were drawbacks, such as a tendency to cause casting troubles such as breakouts. Method (2) is
Since this method can be implemented after the rolling step, it has an advantage that it can be easily adapted to the condition of the slab, but it is extremely difficult to design the manufacturing process because many steps affect each other in a complicated manner. For example, if you try to increase the number of recrystallizations, you have to increase the number of steps, if you try to promote recrystallization in one step, the recrystallization in other steps becomes insufficient, the thickness of the slab and the final product Since the optimum process differs depending on the thickness, there is a degree of freedom in the process design, and a situation arises in which the process must be changed for each slab. Moreover,
Recrystallization alone is not enough to randomize the texture, making it necessary to use precipitates and devising a rolling method, which complicates both components and manufacturing technology. It had many drawbacks, including the potential for increased costs. The method (3) is extremely effective in destroying the cast structure because it utilizes transformation as in the case of carbon steel. However, the composition and the heat process are limited, and most commonly used in ferritic stainless steel sheets. SUS4
It is not applicable to 30 steels, so it is a solution only applicable to special steel types. In addition, since the transformation phase is generally hard, deterioration of mechanical properties such as ductility and workability cannot be avoided.

As described above, these methods are effective, but are insufficient, degrade other characteristics, are extremely difficult to control, or are disadvantageous in terms of cost. However, it has not been possible to eliminate the ridging phenomenon at a practical level. In view of this situation, a ferritic stainless steel sheet with improved ridging properties that does not deteriorate mechanical properties such as ductility and workability, and that has a simple manufacturing process and is relatively easy to implement technically. As a manufacturing method, the following manufacturing method is disclosed in Japanese Patent Application No. Hei.
-170489 filed.

The gist of the manufacturing method is that γ precipitates at a high temperature.
The phase was dispersed in the ferrite grains, and a shear deformation was introduced at the center of the sheet thickness by utilizing the difference in high-temperature deformability from the ferrite phase, thereby attempting to destroy the solidified structure. For this reason, it is very effective to disperse and precipitate the γ phase in the grains by adding B, which is easy to segregate at the ferrite grain boundaries and is a ferrite forming element. However, if a large amount of B is added, low-melting-point boride is generated from conventional knowledge, causing hot-grained intergranular cracking, resulting in frequent occurrence of rolling surface defects. Therefore, without adding B to the surface layer,
By adding B only to the central part of the sheet thickness, a ferritic stainless steel excellent in surface properties and ridging properties is manufactured.

[0008] However, adding B only to the center of the sheet thickness is generally costly and not practical. For example, it is technically easier to achieve with a clad steel sheet by the rolling method or the casting method.However, in the rolling method, large costs are inevitable for assembling the slab and refining the interface. The method of adding B to the center at the time of casting also requires special work inside the mold, refining of the interface or
Special equipment such as a heavy nozzle is required, and large costs are inevitable. For this reason, the method for producing a ferritic stainless steel having improved surface properties and ridging properties is disadvantageous in terms of cost.

In view of such circumstances, the present invention provides a method of manufacturing a ferritic stainless steel sheet which has a simple working process and requires no special equipment, and as a result, has a low manufacturing cost, has no rolled surface eaves, and has excellent ridging properties. And B to provide an optimal wire.

[0010]

As a method of providing a component difference between the central portion of the plate thickness and the surface layer portion, there is a method of cladding in a solid phase or a liquid phase as described above. However, in the case of the steel according to the present invention, the component difference between the plate thickness center portion and the surface layer portion is only B,
The difference between the concentrations does not necessarily have to be large. In order to provide a slight concentration difference, it is not always necessary to adopt a method by cladding established as a conventional technique.

Therefore, the present inventors have recalled that B is injected only into the central part by utilizing the diffusion including the stirring in the liquid phase. That is, if the slab surface layer portion corresponding to the thickness of the predetermined product plate surface layer portion is solidified during continuous casting, then a wire wrapped with a material containing B with a coating material that is melted by molten steel from the upper part of the mold is injected. In the liquid phase portion, the substance containing B dissolves and immediately diffuses into the entire liquid phase portion, that is, the central layer of the slab. However, there is only diffusion in the solid phase portion in accordance with the diffusion rate in the solid phase. Naturally, the diffusion in the solid phase is much slower than the diffusion in the liquid phase, so that B is not actually diffused into the solid phase portion of the surface layer and the solidification is completed without containing B. Therefore, according to this method, it is possible to add the element only to the inner layer of the slab without requiring any special equipment or process.

Regarding the wire to be added and inserted into the mold, first, the outer shell is melted by the latent heat inside the mold,
The dissolution rate is not very rapid, and the material constituting the core material in the center does not dissolve at the intended depth, and the wire must maintain a suitable strength at the intended depth. Also, the core material at the center portion, of course, contains B, but is quickly melted by the latent heat inside the mold, and B is sufficiently homogenized at a higher dissolution rate than the outer skin. And, as a whole, it is necessary that the constituent elements other than B do not affect the components of the mother molten steel and are hardly segregated.

It has been confirmed that the above-mentioned method of adding B at the center can be actually implemented at the time of casting a ferritic stainless steel. The present invention has been made by developing a wire using a B compound such as ferro-B as the core material of the portion, and the gist thereof is as follows. (1) In a base molten steel containing 10 to 23% of Cr by weight%,
A wire wrapped with a coating material that melts a substance containing B in molten steel is inserted into the unsolidified portion in the mold or immediately below the mold during continuous casting, and B is melted and solid-dissolved. A method for producing a ferritic stainless steel sheet having no rolled surface eaves and excellent ridging properties, characterized by adding -300 ppm.

(2) The slab center to which B is added is a center portion deeper than a position which is 10 to 35% of the total thickness from the surface of the slab. A method for producing a ferritic stainless steel sheet having excellent ridging properties without a rolled surface eaves. (3) The base molten steel is, by weight%, C: 0.08% or less, S
i: 0.05 to 1.0%, Mn: 0.05 to 1.0%,
(1) or (2), wherein acid-soluble Al: 0.001 to 0.2%, N: 0.06% or less, Cr: 10 to 23%, and the balance Fe and unavoidable impurities. A method for producing a ferritic stainless steel sheet having excellent ridging properties without the above-mentioned rolled surface eaves.

(4) The mother molten steel further comprises one or more of Ni: 2% or less, Mo: 3% or less, and Cu: 1% or less by weight. 3. The method for producing a ferritic stainless steel sheet having no rolled surface eaves and excellent ridging properties according to 3).

(5) The outer shell is a metal material having a lower melting point than the ferritic stainless steel to which B is to be added,
The core material of the central portion is made of one or a mixture of a B-containing alloy and a B-containing compound, wherein B is used for producing a ferritic stainless steel having no rolled surface eaves and excellent ridging properties. Wire. (6) The outer skin is austenitic stainless steel,
A ferrite excellent in ridging property without a rolled surface eaves, characterized in that the core material at the center is made of one or a mixture of B-containing alloy, ferroboron, Fe-boride, and Cr-boride. B-adding wire used for the production of stainless steel.

(7) The austenitic stainless steel of the outer skin is expressed by weight%, C: 0.08% or less, Si: 0.05
To 2.0%, Mn: 0.05 to 2.0%, N: 0.0
6% or less: Cr: 10 to 20% Ni: 4 to 10%, and the balance is Fe and unavoidable impurities. The ferritic stainless steel according to (6), which has no rolled surface eaves and has excellent ridging properties. Wire for B addition used in the production of

(8) The wire according to any one of (5) to (7), wherein the wire wrapped with the coating material that melts the substance containing B in molten steel is the wire according to any one of (5) to (7).
(4) The method for producing a ferritic stainless steel sheet according to any one of (4), which does not have a rolled surface eaves and has excellent ridging properties.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a coating which melts with molten steel from the upper part of a mold after solidification of a slab surface portion corresponding to a thickness of a surface layer portion to which B is not added in a predetermined product plate during continuous casting. The gist of the present invention is to inject a wire wrapped with a material containing B in a material. In the liquid phase portion, the substance containing B dissolves and immediately diffuses into the entire liquid phase portion, that is, the central layer of the slab. However, there is only diffusion in the solid phase portion in accordance with the diffusion rate in the solid phase. Naturally, the diffusion in the solid phase is much slower than the diffusion in the liquid phase, so that B is not actually diffused into the solid phase portion of the surface layer and the solidification is completed without containing B.

According to this method, it is possible to add the element only to the inner layer of the slab relatively easily without requiring any special equipment or process, which is very advantageous in terms of cost. The thickness of the surface layer portion to which B is not added can be controlled by changing the type and thickness of the coating material of the wire that is melted by molten steel. Although the present invention does not specify the details of the steelmaking equipment, if the influence of the convection of molten steel in the mold is significant, the method of adding the wire is limited, so that the convection is performed by an electromagnetic brake or a similar method. Is preferably reduced.

Next, the limiting conditions of the present invention will be described. If the Cr content of the base molten steel is less than 10%, the basic corrosion resistance of a stainless steel plate is insufficient, so the lower limit was set. On the other hand, if it exceeds 23%, the ductility and the workability are reduced, and it cannot be used for a processing purpose which causes a problem of ridging. As disclosed in Japanese Patent Application No. Hei 9-170489, the B content in the center of the slab added by the solid solution of the wire is less than 30 ppm, since no ridging improvement effect is observed.
Even if the addition exceeds 0 ppm, the effect of improving the ridging due to the fine dispersion of the γ phase is saturated and the cost is disadvantageous. Therefore, the addition is carried out at 30 to 300 ppm.

In the above (2), the portion of the slab center layer portion to which B is added is 10 to 3 times of the total slab thickness from the surface of the slab.
The inner layer is deeper than the 5% position. Japanese Patent Application No. 9-17
As disclosed in Japanese Patent No. 0489, B is less than 30 ppm in a surface layer portion having a thickness of 10% or less, and 30 ppm or more B is necessary in a central portion having a thickness of 35% or more in a steel plate after rolling. Therefore, the boundary between the addition and the non-addition of B was set at a position of 10 to 35% of the slab thickness.

Regarding the component limitation shown in the above (3),
If C exceeds 0.08%, the ductility becomes poor, so the upper limit was set. If the content of Si is less than 0.05%, there is a risk that the deoxidization becomes insufficient and a large amount of nonmetallic inclusions remain. Since it is possible to reliably perform deoxidation by other methods, there is no problem if it is less than 0.05% in that case, but since the cost to reduce to that level is required,
The lower limit was set. On the other hand, if the content exceeds 1.0%, not only is the material hardened and the workability of the final product deteriorates, but also the hot workability deteriorates, so the upper limit was set.

When Mn is less than 0.05%, S, which is an unavoidable impurity, is insufficiently fixed and causes surface flaws. However, if it exceeds 1.0%, the furnace material at the time of refining is deteriorated and disadvantageous in cost, so the upper limit is set to 2%. If the acid-soluble Al content is less than 0.001%, the deoxidation becomes insufficient, and a large amount of nonmetallic inclusions remain to deteriorate workability and corrosion resistance. However, if it exceeds 0.2%, ductility deteriorates, so the upper limit was set.

If N exceeds 0.06%, the precipitation of Cr nitride increases and the workability and corrosion resistance are deteriorated. In the above (4), the element to be further added is N
i is an element that increases the γ potential, but needs to be added to the surface portion in consideration of the fact that corrosion resistance exerts an effect mainly on the surface side. Therefore, if a large amount is added, the γ-potential of the surface layer portion is increased, and a large amount of a γ-potential lowering element (Cr, Si, Al, Mo, etc.) is required, and the ductility is greatly reduced. 2.0% was made the upper limit.

Mo, on the other hand, is an element which lowers the γ potential, but when added in large amounts, any of them becomes hard and deteriorates ductility, so the upper limit is 3%. Cu is N
Like i, it is an element that raises the γ potential, but must be added to the surface part in view of the fact that corrosion resistance mainly exerts an effect on the surface side. Therefore, if a large amount is added, the γ potential in the surface layer portion is increased, and γ
Potential lowering element (Cr, Si, Al, Mo, etc.)
Since the addition of a large amount of N is required and the ductility is greatly reduced, the upper limit is made 1.0%.

In the steel produced by the production method of the present invention, texture randomization occurs in the surface layer and the central part by different mechanisms,
Ridging is improved. In the surface layer, even if the composition is not particularly controlled and the structure is not controlled, the texture is sufficiently randomized by the shear deformation at the time of hot rolling, and the ridging property is improved. On the other hand, since the shear deformation due to rolling cannot be expected at the center, a relatively large amount of hard γ phase is present in the α phase during rolling, and microscopic shear deformation is applied by utilizing the difference in hardness. Thus, randomization in a collective manner is performed, and the ridging property is improved. At this time, if B is contained in the central portion, the γ phase is finely dispersed in the ferrite grains, so that a microscopic shearing effect is exerted on the entire ferrite grains.
Further, since B is added only to the central layer, no surface flaw at the time of hot rolling caused by boron is generated.

The wire for adding B has a sectional shape as schematically shown in FIG. In FIG. 1, 1 is an outer skin, and 2 is a core material at the center. Since the core material at the center of the wire is for adding B, it needs to contain B, and needs to be melted by the latent heat of molten steel. for that purpose,
B-containing alloys such as Ferro-B are suitable. Further, in the normal temperature region, a boride which often exists as a precipitate in steel is used. Among them, borides of Fe and Cr which are already contained in the intended ferritic stainless steel, do not form a special compound even when they are dissolved, and have no problem in components are selected. Specifically, there are Fe ₃ (C, B) and Cr ₂₃ (C, B) ₆ . In addition to this, although relatively expensive, other borides such as Cr ₇ (C, B) ₃ can be used, and a mixture of these can be used without any problem. These borides have good wettability with molten steel and a high dissolution rate in molten steel. Also, when an alloy is used instead of nonmetallic powder as the core material, the contact area with the molten steel becomes small, and depending on the amount of latent heat, that is, the speed of drawing the slab, if the diffusion of the solid solution element is insufficient or severe, Care must be taken because there is a concern that the wire remains undissolved, but the workability of the wire is improved and the operability at the time of adding the mold is improved.

The outer sheath of the wire has a melting point lower than the melting point of the mother molten steel, and it is necessary that the composition of the mother molten steel does not significantly change even if it is melted. In addition, it is indispensable that the core material powder and the like at the center part are retained, and that bending and the like are easy and operability at the time of adding a mold is not hindered. As a material satisfying the above requirements, stainless steel is suitable. In particular, C
An austenitic stainless steel having a large r content is a more preferable material for the outer skin because there is no concern that the Cr amount is reduced due to the melting of the outer shell and the corrosion resistance is deteriorated, and the bending workability is very good. The present invention is not limited to austenitic stainless steel according to standards such as the so-called JIS, but is included in the present invention as long as the main room-temperature crystal structure is an austenitic phase.

The reason for limiting the components related to the wire of the present invention defined in the above (7) is that if C exceeds 0.08%, the workability of the wire is deteriorated and the operability of the adding operation is impaired. The upper limit was set. If the content of Si is less than 0.05%, there is a risk that a large amount of nonmetallic inclusions may remain due to insufficient deoxidation, and there is a risk that the workability of the surface layer of the ferritic stainless steel to be added and inserted is deteriorated. Since deoxidation can be reliably performed by other methods, there is no problem if it is less than 0.05% in this case, but the cost for reducing the level to that level is required, so the lower limit was set. on the other hand,
When the content exceeds 2.0%, not only the workability of the surface layer of the ferritic stainless steel to be added and inserted is deteriorated, but also the hot workability of the steel itself is deteriorated.

If the content of Mn is less than 0.05%, the fixing of S, which is an unavoidable impurity, becomes insufficient, causing surface flaws. To degrade the corrosion resistance
The lower limit was set. However, if a large amount is added, the furnace material at the time of refining deteriorates and the cost becomes disadvantageous, so the upper limit is set to 2%.

If the content of Cr is less than 10%, the basic corrosion resistance of stainless steel is insufficient, and rust occurs at the time of wire handling, the O content in the ferritic stainless steel base molten steel increases, and the corrosion resistance of the ferritic stainless steel decreases. The lower limit was set for deterioration. On the other hand, if it exceeds 20%, the ductility and workability of the surface layer of the ferritic stainless steel to which the additive is inserted are reduced, so the upper limit is set.

If Ni is less than 4%, the austenitic phase of the austenitic stainless steel of the outer skin becomes unstable,
The lower limit was set because the bendability deteriorated and the operability such as mold insertion was significantly deteriorated. On the other hand, if it exceeds 10%, the austenite potential after melting increases, and there is a concern that the γ-phase remains even after cold-rolling annealing and the workability is reduced.

If N exceeds 0.06%, a large amount of Cr nitride precipitates after melting and the corrosion resistance deteriorates. As described above, since the wire according to the present invention does not use any special elements, there is no need to generate special precipitates, alloys, and intermetallic compounds for the mother molten steel,
When casting ferritic stainless steel, B can be efficiently added to the center of the ferrite stainless steel, and since it is a stainless steel shell, it has good bendability and corrosion resistance, and is handled during mold insertion and wire production. Is extremely easy and there is no problem due to rust or the like. Therefore, in the manufacturing method according to any one of the above (1) to (4), a wire wrapped with a coating material that melts a substance containing B in molten steel as described in any one of the above (5) to (7). By using the described wire, it is possible to provide a more preferable method for producing a ferritic stainless steel sheet having no rolled surface eaves and excellent ridging properties.

[0035]

<Example 1> When continuously casting ferritic stainless steel molten steel having the chemical composition shown in Table 1, SUS304 was used.
A wire filled with ferro-B was inserted into a steel pipe from the top of the mold to produce a slab 190 mm thick. This slab is hot-rolled to 4 mm by a usual method, descaled without performing hot-rolled sheet annealing or without performing hot-rolled sheet annealing, cold-rolled to 0.5 mm, and 925 ° C.
A final annealing of -5 min was performed. The ridging property was determined by cutting out a JIS-5 test piece from the final cold-rolled annealed sheet, pulling it in the rolling direction by 20%, and evaluating the height of the striped undulation generated in the direction perpendicular to the rolling direction.

[0036]

[Table 1]

Table 2 also shows the B content in the surface layer and the central portion, the occurrence of flaws in the hot-rolled sheet, and the ridging property of the cold-rolled annealed sheet. The ferritic stainless steel produced by the method of the present invention had no surface flaws at the time of hot rolling and had very small cracks at the ends. The cold-rolled steel sheet has a ridging height of 20μ.
m. However, no. Even in the case where B was added to the central layer as in Comparative method 5, the ridging improvement effect was small when the added amount was less than 30 ppm. In addition, No. The steel sheet in which B was added to the total sheet thickness according to the comparative method 6 had good ridging properties of less than 20 μm, but had many surface flaws after hot rolling and poor cracks at the edges. No. As in the method of Comparative Example 7, those without the addition of B had good surface flaws after hot rolling, but had poor ridging properties.

[0038]

[Table 2]

Example 2 C: 0.33% by weight,
Si: 0.22%, Mn: 0.25%, Cr: 16.3
%, Soluble Al: 0.022%, N: 0.0107%,
When continuously casting a ferritic stainless steel molten steel comprising the balance of Fe and unavoidable impurities, a wire having the structure shown in Table 2 was added and inserted into a mold to produce a cast piece. After that, hot rolling, annealing, and cold rolling are performed in the usual manner,
A 0.5 mm cold-rolled annealed plate was manufactured. The ridging property of the cold-rolled annealed sheet was evaluated based on the height of a striped undulation generated in a direction perpendicular to the rolling direction by pulling a JIS-5 test piece in the rolling direction by 20%.

No. The cast slabs to which the wires of the present invention of 1 to 4 were added and succeeded in adding B only to the center layer,
It was possible to achieve the goal as a wire for insertion insertion in a continuous casting mold used for improving ridging of ferritic stainless steel. However, no. When the outer skin of No. 4 was Cu, the Cr concentration of the molten steel in the surface layer portion was slightly reduced as compared with the base molten steel.

However, no. In the wire of No. 5, the outer skin was not completely melted in the mold, a cluster-like undissolved ferro-B community was observed in addition to a part of the steel pipe inserted and added by a cast slab, and even in the final product, an inclusion-like high B Low Cr communities remained. No. The same applies to the wire of No. 6, and the unmelted SS4
A massive ferro-B phase and bubbles remained with the 00 steel.

[0042]

According to the method of the present invention, a method for producing a ferritic stainless steel sheet excellent in ridging properties without a rolled surface eaves at low cost, and a B-adding wire capable of performing the production method more easily and reliably. For applications where austenitic stainless steel containing a large amount of expensive Ni had to be used for reasons of surface properties only in spite of the fact that it was not necessary from the viewpoint of corrosion resistance, inexpensive ferritic stainless steel was used. It is possible to apply.

[Brief description of the drawings]

FIG. 1 is a schematic view of a cross-sectional shape of an addition insertion wire according to the present invention.

[Explanation of symbols]

 1 ... outer skin 2 ... core material

Claims (8)

[Claims] 1. A method of wrapping a base molten steel containing 10 to 23% by weight of Cr with a coating material that melts a B-containing substance in a molten steel in a central unsolidified portion in or immediately below a mold during continuous casting. A method for producing a ferritic stainless steel sheet having no rolled surface eaves and excellent ridging properties, characterized by adding 30 to 300 ppm of B to the center of the slab by inserting a melted wire into a molten solid solution. 2. The rolled surface according to claim 1, wherein the center of the slab to which B is added is a center deeper than a position which is 10 to 35% of the total thickness from the surface of the slab. A method for producing a ferritic stainless steel sheet with no eaves and excellent ridging properties. C .: 0.08% or less by weight of mother molten steel, 0.05 to 1.0% of Si, 0.05 to 1.0% of Mn, and 0.05 to 1.0% of acid-soluble Al. 001 to 0.2%, N: 0.06% or less, Cr: 10 to 23%, and the balance is Fe and unavoidable impurities. Method for producing ferritic stainless steel sheet with excellent quality. 4. The mother molten steel further contains one or more of Ni: 2% or less, Mo: 3% or less, and Cu: 1% or less by weight%. The method for producing a ferritic stainless steel sheet having excellent ridging properties without a rolled surface eaves as described in 1 above. 5. The outer shell is a metal material having a lower melting point than the ferritic stainless steel to which B is to be added, and the core material at the center is made of a B-containing alloy or a mixture of one or more B-containing compounds. A B-adding wire for producing a ferritic stainless steel having no rolled surface eaves and excellent ridging properties. 6. The outer skin is austenitic stainless steel, and the core material at the center is a B-containing alloy, ferroboron, F
e, which is composed of one or a mixture of two or more of boride chromium and chromium boride, which is used for producing a ferritic stainless steel having no rolled surface eaves and excellent ridging properties.
Additive wire. 7. The austenitic stainless steel of the outer skin is expressed by weight%, C: 0.08% or less, Si: 0.05 to 2.0%, Mn: 0.05 to 2.0%, N: 0. 7. The ferritic stainless steel according to claim 6, wherein the ferrite stainless steel has no rolling surface eaves and has excellent ridging properties, wherein the content is 0.6% or less, Cr: 10 to 20%, Ni: 4 to 10%, and the balance is Fe and inevitable impurities. Wire for B addition used in the production of 8. A wire according to any one of claims 5 to 7, wherein the wire wrapped with a coating material that melts a substance containing B in molten steel is the wire according to any one of claims 5 to 7. A method for producing a ferritic stainless steel sheet having excellent ridging properties without the above-mentioned rolled surface eaves.