KR20110071516A - Martensitic stainless steels containing high carbon content and method of manufacturing the same - Google Patents

Abstract

PURPOSE: A high carbon martensite stainless steel and a manufacturing method thereof are provided to remarkably reduce the size of primary carbide formed at the coagulating structure by applying a strip casting method. CONSTITUTION: A method for manufacturing high carbon martensite stainless steel comprises the next step. Stainless molten steel containing C of 0.40~0.80% and Cr of 11~16% is supplied from a turndish through a nozzle to a steel pool to cast a stainless thin plate. A hot rolled strip is manufactured at a reduction ratio of 5~40% from the stainless thin plate using an inline roller such that primary carbide in the hot rolled strip micro-structure becomes 10μm. Martensitic stainless steel is composed of Si of 0.1~1. 0%, Mn of 0.1~1. 0%, Ni of 0~1.0%, N of 0~0.1%, S of 0~0.04%, P of 0~0.05%, residual Fe and other impurities.

Description

Martensitic stainless steels containing high carbon content and method of manufacturing the same

The present invention relates to a high carbon martensitic stainless steel and a method for manufacturing the same, and more particularly, to manufacturing a high carbon martensitic stainless steel containing 0.4 to 0.8% carbon and 11 to 16% chromium using a strip casting process. The present invention relates to a high carbon martensitic stainless steel with a reduced primary carbide size and a method of manufacturing the same.

In general, high carbon martensitic steels containing 0.40% or more by weight of carbon are used for razor blades and knives because of their excellent corrosion resistance, hardness and wear resistance. As such, when using a razor blade drawn using high-carbon martensitic stainless steel used for razor blades, the razor blade is used in contact with moisture in the shaving process.

In addition, such razor blades are also stored in a humid atmosphere and therefore require corrosion resistance. However, such an environment is too harsh for high carbon steel to be used and usually martensitic stainless steel containing about 13% of chromium is mainly used. Razor blades made of martensitic stainless steels contain about 12% or more of chromium, a matrix of martensite, by weight, resulting in a dense formation of thin chromium oxide on the surface of the razor blade. It serves to inhibit corrosion.

On the other hand, shaving is a process of cutting a beard by closely attaching a blade to a material, and above all, high hardness is required to cut a high strength beard. The high hardness level required by the razor blade is achieved by the martensite matrix of the steel. Martensite tissue is a very hard microstructure that is produced when the hot austenite is cooled rapidly. The higher the content of carbon dissolved in the high temperature austenite phase, the higher the carbon dissolved in martensite and the higher the martensite hardness. Therefore, in order to produce a razor blade steel having a high hardness, as much carbon as possible should be added to the steel.

Usually, 420 series martensitic stainless steels are mainly used for razor blades which satisfy the above requirements in terms of corrosion resistance and hardness. These steels contain 0.45 to 0.70% carbon by weight, up to 1% manganese, up to 1% silicon, and 12 to 15% chromium, among others, based on about 0.65% and about 13% chromium. Is commonly used a lot.

On the other hand, the blade thickness is generally 0.2 mm or less. Therefore, a very thin high carbon martensitic stainless steel having a thickness of 0.2 mm or less is used as an initial material for producing a razor blade. This initial material has a microstructure composed of ferrite matrix and fine chromium carbide evenly distributed. At this time, the distribution of fine chromium carbides enables the rapid re-solubilization of carbon into the hot austenite phase in the subsequent hardening process, thereby controlling the martensite transformed by cooling to have sufficient hardness to be used as a razor blade. It is an argument.

In addition, the size of the chromium carbide of the initial material can be defined as the number of chromium carbides per unit area, and when observed at a high magnification of 10,000 times, more than 50 chromium carbides having a size of 0.1 µm or more should be present in an area of 100 µm ² . . The initial material is slit to the appropriate width, coiled and then subjected to several subsequent steps to produce a razor blade. Subsequent processes include a hardening process that heats and maintains a high temperature austenite zone and then cools it to give high hardness, a sharpening process of the razor blade, and a coating process to impart wear resistance and lubricity. And a welding process for mounting the blade to the razor.

In addition, the initial material of the thin material (0.2 mm or less in thickness) used to manufacture the razor blade should be free of coarse chromium carbide in the microstructure, for the following reasons. When coarse chromium carbide is present, coarsening of coarse chromium carbide occurs at the edge portion of the blade during the subsequent process of sharpening the blade, resulting in a dull edge of the blade edge. This phenomenon is called edge tear-out, which is the main cause of injury to the skin during shaving. In addition to coarse chromium carbide, coarse inclusions also cause edge dropout. In terms of edge drop, the maximum size of chromium carbide is 10 mm. Coarse chromium carbide having a size of 10 µm or more present in the initial material and acting as a major cause of edge dropping is coarse primary carbide produced during casting. This coarse primary carbide is distinguished from the fine chromium carbide that occurs during the hot or heat treatment of the alloy. Coarse primary carbides are produced by segregation that occurs between dendrite arms during the solidification process of high carbon martensitic steels. Since segregation of carbon and chromium is a natural phenomenon occurring during solidification, formation of primary carbide cannot be avoided, but its size should be minimized during the solidification process to prevent edge dropping.

This edge drop problem is not only a razor blade, but also an important quality factor that determines blade quality in general ceramic applications. As described above, in order to manufacture a razor blade having a high hardness, as much carbon as possible can be added to the steel, but the higher the carbon content, the coarse primary carbide is formed during solidification, making it difficult to manufacture a high quality razor blade.

For this reason, conventionally known Japanese Patent No. 61034161 proposes an alloy component system having a carbon content of 0.40 to 0.55% in order to minimize edge dropout by primary carbide. In particular, the ingot casting method generally used in the manufacture of razor blade steel has a disadvantage in that initial carbide is formed coarse because segregation is severely generated. Because of these drawbacks, in order to re-primary the primary carbides or to make them smaller, hot processing such as additional heat treatment and forging in the ingot is essential.

Therefore, in order to manufacture high quality razor blades, a method of suppressing the formation of coarse primary carbides during casting is desired. In particular, it is necessary to develop an economical casting method that can effectively reduce the size of the primary carbide in the microstructure without lowering the carbon content compared to conventional razor blade steel.

The present invention has been devised in accordance with the above requirements, and newly utilized the strip casting method for the purpose of replacing the existing ingot casting method mainly used for manufacturing high carbon martensitic steel. The present invention has an object of presenting a method for economically manufacturing high carbon-containing martensitic stainless steel while significantly inhibiting coarse primary carbides produced during solidification, which is a major disadvantage of the conventional ingot production method. .

In order to achieve the above object, the present invention provides a pair of rolls rotating in opposite directions and an edge dam installed to form molten steel pools on both sides thereof and a meniscus shield for supplying inert nitrogen gas to the molten steel pool upper surface. In the strip casting apparatus including, by weight by weight, molten stainless steel containing C: 0.40 to 0.80%, Cr: 11 to 16% is supplied from the tundish to the molten steel pool through a nozzle to cast the stainless steel sheet, and the casting Made of high carbon martensitic stainless steel to make primary carbide less than 10㎛ in the hot rolled strip microstructure by manufacturing hot rolled strip by casting ingot rolled sheet at 5 ~ 40% using inline roller. It provides a manufacturing method.

Further, in the present invention, the martensitic stainless steel is Si: 0.1 to 1.0, Mn: 0.1 to 1.0, Ni: more than 0 and less than 1.0, N: more than 0.1 and less, S: more than 0 and less than 0.04, P: Provided is a method for producing a high carbon martensitic stainless steel consisting of Fe and other than 0.05 or less and the balance of Fe and other unavoidable impurities.

Further, in the present invention, the hot rolled strip may be subjected to batch annealing in a temperature range of 700 to 950 ° C. under a reducing gas atmosphere to produce high carbon martensitic stainless steel.

In addition, in the present invention, the above-mentioned annealing is preferably performed in a range of 1 to 3 times.

In addition, in the present invention, the hot-annealed strip subjected to the annealing may be subjected to pickling after shot blasting.

In addition, in the present invention, the depth of the decarburized layer in the pickled hot rolled strip may be 20 μm or less directly below the surface scale.

In addition, in the present invention, the hot rolled strip may be subjected to subsequent cold rolling, and in this case, it is preferable that the one-time cold rolling rate is 70% at maximum.

In addition, in the present invention, the cold rolled strip may be subjected to annealing of five times or less in a reducing gas atmosphere.

In addition, in the present invention, when the carbide is observed at a magnification of 10,000 times, the hot rolled strip may have 50 or more chromium carbides having a size of 0.1 μm or more per 100 μm 2.

According to yet another aspect of the present invention, a pair of rolls rotating in opposite directions and an edge dam provided to form molten steel pools on both sides thereof and a meniscus shield for supplying inert nitrogen gas to the molten steel pool upper surface are provided. In the strip casting apparatus comprising a, by weight%, C: 0.40 ~ 0.80%, Cr: 11-16% containing stainless molten steel from the tundish to the molten steel pool through a nozzle to cast a stainless steel sheet, High-carbon martensitic stainless steel that makes primary carbide less than 10㎛ in hot-rolled strip microstructure by manufacturing hot-rolled strip using cast in-line roller at 5 ~ 40% reduction rate after casting Can provide river

As described above, the present invention is characterized by applying a strip casting method of manufacturing a hot rolled coil directly from molten steel manufactured by a steelmaking process. Strip casting can innovatively reduce the size of primary carbides formed in solidified tissue, which can be very useful for producing high quality razor blades. In particular, since the hot rolled coil is manufactured directly from molten steel as well as the quality of the razor blade, the manufacturing process of the hot rolled coil is simple compared to the existing ingot casting method, and thus the manufacturing cost is very low.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention and other matters required by those skilled in the art will be described in detail with reference to the accompanying drawings. However, the present invention may be embodied in various different forms within the scope of the claims, and thus the embodiments described below are merely exemplary, regardless of expression.

In describing the present embodiment, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. It should be noted that the same elements in the drawings are represented by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In addition, the thickness and size of each layer in the drawings may be exaggerated for convenience and clarity, and may differ from actual layer thicknesses and sizes.

1 is a schematic diagram of a conventionally known stripcasting installation. This strip casting process produces hot rolled strips of thin metal directly from molten steel, eliminating the hot rolling process, and is a new steel processing process that can drastically reduce manufacturing costs, equipment investment costs, energy consumption, and pollution gas emissions. As shown in FIG. 1, a twin roll sheet caster used in a general strip casting process receives molten steel in a ladle 1, flows into a tundish 2 along a nozzle, and flows into a tundish 2. The silver is supplied through the molten steel injection nozzle 3 between the edge dams 5 provided at both ends of the casting roll 6, that is, between the casting rolls 6 to start solidification. At this time, the molten portion between the rolls to protect the molten surface with the meniscus shield (4) in order to prevent oxidation and inject the appropriate gas to properly control the atmosphere. The thin plate 8 is manufactured and drawn while rolling out the roll nip 7 where both rolls meet, and then rolled through the rolling mill 9 and then wound up in the winding facility 10 through a cooling process.

At this time, an important technique in the twin roll sheet metal casting process for directly manufacturing a sheet having a thickness of 10 μm or less from molten steel is supplying molten steel through an injection nozzle between inner water-cooled twin rolls rotating at opposite speeds at a high speed to obtain a thin sheet having a desired thickness. It is manufactured so that there is no crack and the error rate is improved.

The present invention relates to a method for producing high strength martensitic stainless steel using a strip casting process, in particular high carbon martensitic stainless steel containing 0.40 to 0.80% carbon and 11 to 16% chromium as the main component by weight%. Since the production by using the strip casting method, by reducing the size of the primary carbide formed in the casting structure to 10㎛ or less, it is characterized in that the high-carbon martensitic stainless steel for razor blade having excellent blade quality.

Strip casting process, a feature of the present invention, is a manufacturing method of minimizing segregation generated during casting by applying a very fast cooling rate to a cast plate while directly casting a liquid steel into a sheet having a thickness of 1 to 5 mm. In the present invention, a hot rolled coil was manufactured using a twin roll strip caster. Twin-roll strip casters are characterized by casting molten steel between twin-drum rolls and side dams rotating in opposite directions and releasing a large amount of heat through the roll surface to be cooled. At this time. On the surface of the roll, a solidification cell is formed at a high cooling rate, and a thin hot rolled sheet of 1 to 5 mm is manufactured by inline rolling continuously performed after casting.

(Example)

Hereinafter, the present invention will be described by way of examples.

The base material used in the present invention is a high carbon martensitic stainless steel, C: 0.4 ~ 0.8%, Cr: 11 ~ 16% range is used. In the present invention, when the range of C is 0.4% or less, a lot of primary carbides are not generated in the strip or ingot, but the hardness is not preferable. In addition, when the content is 0.8% or more, it may be difficult to suppress the production of primary carbide even if produced by strip casting. Therefore, the present invention proposes C: 0.4 to 0.8% and Cr: 11 to 16% as an optimum range.

In addition, the martensitic stainless steel according to the embodiment of the present invention is Si: 0.1 to 1.0, Mn: 0.1 to 1.0, Ni: more than 1.0 or less, N: more than 0.1 or less, S: more than 0.04 in weight% Hereinafter, P: greater than 0.05 and the remainder are alloys related to the component system composed of Fe and other unavoidable impurities.

In the present embodiment, the microhistological characteristics of the steel produced by applying the hot rolled strip produced by the continuous casting method and the strip casting method were compared. Table 1 shows the components of the steel produced by the continuous casting method and the strip casting method. First, in order to compare the microstructure of a material cast by strip casting with a material manufactured by an ingot casting method, a general razor blade steel was manufactured as an ingot, and its components are shown as Comparative Examples of Table 1 (# 1). Ingots were prepared with a weight of 50 kg by vacuum induction melting. The ingots were reheated at a temperature of 1200 ° C., hot rolled into 3.5 mm thick plates, and water cooled immediately after hot rolling. And using a twin roll strip caster to produce a steel of various components in a hot rolled sheet. Each cast 100 tons. The component is shown in Table 2. Using strip casting method, 100 tons of material cast between water-cooled rolls are hot rolled immediately after casting in an in-line roller at high temperature, and continuously rolled into a hot rolled coil having a thickness of 1 to 5 mm. Was prepared.

Steel components manufactured by ingot casting ID C Si Mn P S Cr Ni N primary
carbide
(≥10 μm) Remarks #One 0.67 0.30 0.66 0.002 0.001 13.1 0.05 0.03 has exist Comparative example

Steel components manufactured by strip casting ID C Si Mn P S Cr Ni N primary
carbide
(≥10 μm) Remarks #2 0.65 0.26 0.45 0.019 0.001 12.9 0.39 0.03 none Inventive Example # 3 0.64 0.41 0.61 0.022 0.001 13.7 0.29 0.02 none Inventive Example #4 0.72 0.42 0.68 0.023 0.002 13.4 0.37 0.04 none Inventive Example # 5 0.87 0.25 0.32 0.021 0.001 14.3 0.07 0.02 has exist Comparative example # 6 0.67 0.42 0.64 0.023 0.004 13.4 0.12 0.04 none Inventive Example # 7 0.46 0.40 0.32 0.018 0.002 14.1 0.15 0.02 none Inventive Example #8 0.49 0.55 0.90 0.022 0.002 12.8 0.15 0.03 none Inventive Example # 9 0.67 0.30 0.71 0.021 0.002 12.4 0.01 0.03 none Inventive Example # 10 0.56 0.34 0.38 0.018 0.002 14.5 0.28 0.02 none Inventive Example

The cross-sectional structure of the ingot of the comparative example (# 1) of Table 1 which is the normal component steel cast by vacuum induction melting | dissolution is shown in FIG. And FIG. 3 shows the water cooled microstructure after hot rolling of the component steel according to Comparative Example (# 1). As clearly seen in the microstructure of the ingot of FIG. 2, it shows that coarse primary carbides are irregularly formed between the grains. These coarse primary carbides are not completely re-employed into the matrix even during reheating performed at a temperature of 1200 ° C., so that they remain in the microstructure after hot rolling and are arranged in the rolling direction. This can be confirmed in FIG. 3.

FIG. 4 is a low magnification cross-sectional structure of a 2.1 mm thick hot rolled coil (Tables 2 and # 6) made of strip casting and having similar components as the component steels of the present invention (Tables 1 and # 1) cast into ingots. 5 and 6 show columnar crystal microstructures developed at the surface layer and equiaxed crystal microstructures developed at the center of the thickness of the coil manufactured by strip casting. From the ingot tissues shown in FIGS. 2 and 3 and the stripcasting tissues shown in FIGS. 5 and 6, the size of primary carbides can be compared. That is, when manufactured by the existing ingot casting method can be clearly observed that the coarse primary carbide was formed at 1000 times magnification, in the hot rolled coil manufactured by applying the strip casting shown in Figs. The coarse primary carbide observed in the coagulation structure of 2 and the hot rolled plate of FIG. 3 is not observed in the microstructure of 1000 times magnification. This clearly shows the technical effect of the present invention that in the production of high carbon-containing martensitic stainless steel, the formation of coarse primary carbides can be innovatively suppressed during casting by using the strip casting method. On the other hand, the size of the primary carbide observable with an optical microscope of 1000 times magnification in the hot rolled plate was investigated. These results are summarized in Table 1 and Table 2.

Another advantage of using strip casting in the casting of high carbon martensitic stainless steel is that the manufacturing cost is reduced due to the reduced process compared to the conventional ingot casting method. In order to manufacture high-carbon martensitic hot rolled coils by ingot casting, subsequent hot working processes such as ingot and hot rolling are required. This additional process is a major factor in increasing the manufacturing cost of ingot manufacturing. In addition, the heat treatment process including the cooling of the material and the elevated temperature, which are essential for the subsequent hot working process such as the hot rolling and the hot rolling, should be performed very slowly due to the fear of cracking due to thermal shock, and the material transfer between the processes. Work must also be done carefully at high temperatures, which is very disadvantageous in terms of productivity. The strip casting method has a great advantage of being able to manufacture high-carbon martensitic stainless steel at low cost since the hot rolled coil is manufactured directly without undergoing a separate hot working process including the above-mentioned coalescence.

Inventive steel 6 (# 6) shown in Table 2 as a 2.1 mm thick hot rolled coil manufactured by a strip casting process was subjected to a batch annealing for a long time in a batch heat treatment furnace. At this time, the hot rolled coil was slowly heated to an annealing temperature of 700 ~ 950 ℃ in a reducing atmosphere, and maintained at that temperature for a long time and then slowly cooled in the furnace again. This annealing heat treatment can be carried out at least once to as many as three times. Of course, the greater the number of annealing treatments, the more homogeneous the material can be, which can lead to additional manufacturing costs. The heat treatment in this process converts martensite and residual austenite, which constitute the microstructure of the hot rolled coil, into ferrite and chromium carbide. The hardness of the hot-annealed tissue after this process was about 220 Hv. The annealed hot rolled coil was subjected to shot blasting, and the scale and the decarburized layer of the surface were removed with a pickling solution composed of a mixture of sulfuric acid and sulfuric acid / nitric acid at a temperature of about 70 ° C. At this time, the depth of the decarburized layer was formed at about 20 μm or less directly below the surface scale, and was easily removed by pickling. In general, the ingot manufactured by the ingot manufacturing method is inevitable to heat treatment of the ingot at a high temperature in order to alleviate segregation of the alloying elements generated during casting. Additional work may be required. Although the decarburized layer exists in the coil made by strip casting, the exposure time to the high temperature of 1000 ° C. or more is short within only 5 minutes before cooling after casting, so that the decarburized layer is slightly generated. Therefore, since the hot rolled coil manufactured by the strip casting process can be easily removed from the decarburized layer by pickling, additional coil grinding can be omitted to remove the decarburized layer.

On the other hand, cold rolling was performed on the invention steel (# 6) of Table 2 as a hot-rolled coil after pickling. As described above, since the initial material for producing the blade has a thickness of 0.02 mm or less, a significant cold reduction is required to reduce the thickness of the initial material to the target thickness from the 2.1 mm thick hot-annealed coil. In particular, the razor blade steel is hardened during cold rolling due to the fine carbide present in the microstructure and has a large decrease in ductility. During cold rolling, up to 70% of cold rolling was performed during one cold rolling in order to cold roll to the target thickness while preventing breakage due to edge crack generation. Edge trimming and intermediate annealing were then performed. At this time, the intermediate annealing was performed for a time within 5 minutes at a temperature of about 750 ℃. Cold rolling and intermediate annealing were repeated several times to roll to the final target thickness. In this manner, a cold rolled thin coil having a thickness of 0.075 mm was manufactured. In this case, it is economical to limit the total number of annealing to obtain the cold rolled sheet within 5 times including the number of annealing performed on the hot rolled strip. In the present invention, using an annealing number of less than five times in this way it was possible to further increase the economics in the equivalent quality.

7 and 8 show the microstructure of the coil cold rolled to a thickness of 0.075mm. In the manufactured coil, carbides having a size of 10 μm or more did not exist, and most carbides were uniformly distributed in a size of 0.1 to 1.5 μm. This can be seen through FIG. 8. On the other hand, it can be seen that an advantageous microstructure is formed to prevent edge dropout. In addition, the number of carbides of 0.1 μm or more measured in FIG. 8 is about 120 EA / 100 μm ² , and it can be seen that the microstructures are suitable for producing blades.

As described above, the present invention, by using the strip casting method, compared to the razor blade steel produced by the ingot casting method, by innovatively suppressing the formation of coarse primary carbide, it is possible to economically manufacture high quality razor blades do. While the invention has been described in terms of specific embodiments of razor blade applications, the scope of the invention is not limited to razor blade applications but includes the scope of the claims.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. The scope of the above-described invention is defined in the following claims, which are not bound by the description of the specification, and all modifications and variations belonging to the equivalent scope of the claims will belong to the scope of the present invention.

1 shows a schematic diagram of a typical stripcasting process.

Figure 2 is a tissue photograph showing that coarse primary carbides are formed at the grain boundaries of the cross-sectional microstructure of the ingot cast by the ingot casting method.

FIG. 3 is a texture photograph showing that primary carbides existing in grain boundaries of ingots remain in the hot-rolled sheet microstructure as a microstructure after the hot rolling of the ingot cast by the ingot casting method.

4 is a low magnification cross-sectional microstructure of a hot rolled sheet material which is cast by strip casting and continuously inline rolled at a high temperature after the main structure, showing equiaxed crystals formed at the center of thickness and columnar crystals formed at the surface layer. Figure of organization picture to show.

5 is an organization photograph showing an enlarged columnar region of FIG. 4;

6 is an enlarged tissue photograph of an isometric region of FIG. 4.

7 is a tissue photograph showing a low magnification cross-sectional microstructure of a cold rolled material of a 75 mm thick fabricated product.

FIG. 8 is a tissue photograph showing a high magnification cross-sectional microstructure of a cold rolled material of a thin material manufactured to a thickness of 75 mm. FIG.

(Explanation of symbols for the main parts of the drawing)

1: ladle 2: tundish

3: injection nozzle 4: meniscus shield

5: edge dam 6: casting roll

7: roll nib 8: cast

9: IRM (Roller) 10: Coil Winding Equipment

Claims (20)

In a strip casting apparatus comprising a pair of rolls rotating in opposite directions and an edge dam installed on both sides thereof to form a molten steel pool and a meniscus shield for supplying inert nitrogen gas to the molten steel upper surface. By weight, molten stainless steel containing C: 0.40 to 0.80% and Cr: 11 to 16% is supplied from a tundish to the molten steel pool through a nozzle to cast stainless steel sheets, and the cast stainless steel sheets are cast inline A method for producing a high carbon martensitic stainless steel in which a hot carbide strip is produced at a reduction ratio of 5 to 40% using a roller so that primary carbide is 10 µm or less in the hot rolled strip microstructure. The method of claim 1, The martensitic stainless steel has a weight percent of Si: 0.1 to 1.0, Mn: 0.1 to 1.0, Ni: greater than 0 and less than 1.0, N: greater than 0.1 and less, S: greater than 0 and less than 0.04, P: greater than 0 and less than 0.05 and The balance is a method for producing high carbon martensitic stainless steel consisting of Fe and other unavoidable impurities. The method of claim 1, The hot-rolled strip is subjected to annealing (batch annealing) in a temperature range of 700 ~ 950 ℃ under a reducing gas atmosphere to produce a hot-carbon martensitic stainless steel. The method of claim 3, wherein The above annealing is a method for producing high carbon martensitic stainless steel carried out in a range of 1 to 3 times. The method of claim 3, wherein The hot-annealed strip is subjected to pickling after the shot blasting process of high carbon martensitic stainless steel. The method of claim 5, The method of manufacturing a high carbon martensitic stainless steel having a depth of the decarburized layer in the pickled hot rolled strip is 20㎛ or less directly below the surface scale. The method according to any one of claims 1 to 6, Cold rolling of the hot-rolled strip, the method of manufacturing a high carbon martensitic stainless steel having a single cold rolling reduction of up to 70%. The method of claim 7, wherein The cold rolled strip is a method of manufacturing high carbon martensitic stainless steel in which the annealing is performed no more than five times under reducing gas atmosphere. The method according to claim 1 or 2, The hot rolled strip is a method for producing high carbon martensitic stainless steel in which 50 or more chromium carbides having a size of 0.1 μm or more are present per 100 μm ² when the carbide is observed at a magnification of 10,000 times. The method of claim 7, wherein The annealing is carried out within 5 times in a reducing gas atmosphere to produce a high carbon martensitic stainless steel. In a strip casting apparatus comprising a pair of rolls rotating in opposite directions and an edge dam installed on both sides thereof to form a molten steel pool and a meniscus shield for supplying inert nitrogen gas to the molten steel upper surface. By weight, molten stainless steel containing C: 0.40 to 0.80% and Cr: 11 to 16% is supplied from a tundish to the molten steel pool through a nozzle to cast stainless steel sheets, and the cast stainless steel sheets are cast inline A high carbon martensitic stainless steel that produces a hot rolled strip at a rolling reduction of 5 to 40% using a roller so that primary carbides are less than 10 µm in the hot rolled strip microstructure. The method of claim 10, The martensitic stainless steel has a weight percent of Si: 0.1 to 1.0, Mn: 0.1 to 1.0, Ni: greater than 0 and less than 1.0, N: greater than 0.1 and less, S: greater than 0 and less than 0.04, P: greater than 0 and less than 0.05 and Martensite stainless steel consisting of Fe and other unavoidable impurities The method of claim 10, The hot rolled strip is a high carbon martensitic stainless steel produced by performing annealing in a temperature range of 700 ~ 950 ℃ under a reducing gas atmosphere. The method of claim 13, The above annealing is carried out in a range of 1 to 3 times high carbon martensitic stainless steel. The method of claim 13, The hot-annealed hot rolled strip is a high carbon martensitic stainless steel subjected to pickling after shot blasting. The method of claim 15, A high carbon martensitic stainless steel having a depth of the decarburized layer in the pickled hot rolled strip is 20 μm or less directly below the surface scale. The method according to any one of claims 10 to 16, Cold rolling of the hot-rolled strip, high cold martensitic stainless steel having a single cold reduction rate of up to 70%. The method of claim 17, The cold rolled strip is a high carbon martensitic stainless steel that is subjected to annealing of five times or less in a reducing gas atmosphere. The method of claim 10 or 12, The hot-rolled strip is 10,000 times magnification carbide is chromium carbide 100㎛ ² high carbon martensitic present in more than 50 per stainless steel having the above 0.1㎛ size when observed by the. The method of claim 17, The annealing of the high carbon martensitic stainless steel is carried out within five times under a reducing gas atmosphere.

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