CN108929984B

CN108929984B - Stainless steel and manufacturing method thereof

Info

Publication number: CN108929984B
Application number: CN201710386033.8A
Authority: CN
Inventors: 邵聪
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-05-26
Filing date: 2017-05-26
Publication date: 2021-07-27
Anticipated expiration: 2037-05-26
Also published as: CN108929984A

Abstract

The invention discloses stainless steel and a manufacturing method thereof, relates to the technical field of metal smelting, and aims to solve the problem of poor stability of austenitic stainless steel in the prior art. The stainless steel includes: the chemical components by mass percent are as follows: c, carbon C: 0.02 to 0.08%, Si: 0.2-1.0%, Mn: 2.0-4.0%, Cr: 17.0-18.5%, Ni: 8.0-10.0%, N: 0.12-0.20%, Cu: 1.00-2.00%, molybdenum Mo: 2.1 to 3.3%, niobium Nb: 0.10 to 0.20%, boron B: 0.0015-0.0025%, calcium Ca: 0.0080-0.0120%, less than or equal to 0.0040% of oxygen O, and the balance of Fe and inevitable impurities.

Description

Stainless steel and manufacturing method thereof

Technical Field

The invention relates to the technical field of metal smelting, in particular to stainless steel and a manufacturing method thereof.

Background

Austenitic stainless steels are the most widely used stainless steel materials, and the class includes 300 series and 200 series, and the crystal structure of the materials is the FCC face-centered cubic structure. The fully annealed austenitic stainless steel has the characteristic of being nonmagnetic or non-magnetic. Stainless steel components used in the fields of machinery, electronics, medical treatment, and communications are often required to operate under magnetic, electric, or signal conditions, and thus require components to maintain a completely nonmagnetic characteristic to avoid interfering with signal collection or propagation.

The main steel types of austenitic stainless steels commonly used are: SUS304 series, including SUS304 and low carbon SUS 304L; SUS316 series having higher corrosion resistance, including SUS316 and low-carbon SUS 316L; the nickel saving austenitic stainless steel S20100 series comprises 201 and 202. These grades account for more than 90% of the production and use proportions of austenitic stainless steels. In addition, there are super austenitic stainless steels such as SUS904L and 254SMO, which are high in Cr and Ni, and these materials have high corrosion resistance and are also expensive and expensive. These materials are all nonmagnetic austenitic structures in the fully annealed state. Studies have shown that 304, 201, 316, etc. are the most widely used austenitic stainless steels in which the austenite phase is metastable. Under the combined action of temperature or stress, strain or multiple factors, such as mechanical or deformation processing, long-term stress and the like, the austenite phases can be rapidly transformed into martensite phases, including hcp martensite phase of hexagonal close-packed or alpha 'martensite phase of body-centered cubic BCC structure, and the alpha' martensite phase is magnetic conductive, so that the non-magnetic (non-magnetic) property of the austenitic stainless steel is destroyed, and the material cannot work under the transmission condition of the magnetic field, the electric field or the electromagnetic wave.

Disclosure of Invention

The invention aims to provide stainless steel and a manufacturing method thereof, which are used for solving the problem of poor stability of austenitic stainless steel in the prior art.

In one aspect, the present invention provides a stainless steel comprising: the chemical components by mass percent are as follows: c, carbon C: 0.02 to 0.08%, Si: 0.2-1.0%, Mn: 2.0-4.0%, Cr: 17.0-18.5%, Ni: 8.0-10.0%, N: 0.12-0.20%, Cu: 1.00-2.00%, molybdenum Mo: 2.1 to 3.3%, niobium Nb: 0.10 to 0.20%, boron B: 0.0015-0.0025%, calcium Ca: 0.0080-0.0120%, less than or equal to 0.0040% of oxygen O, and the balance of Fe and inevitable impurities.

Optionally, the chemical composition satisfies the following relationship:

Ms＝1305-61.6Ni-41.7Cr-33.3Mn-27.8Si-1667(C+N)≤-350℃

and Md30/50 is 580-C-2 Si-16Mn-23Ni-300N-26Cu-10Mo is less than or equal to-115 ℃;

wherein Ms is the highest temperature at which the stainless steel starts to undergo martensitic transformation during cooling, and Md is the highest temperature at which the stainless steel deformation induces martensitic transformation.

Optionally, the chemical composition of the stainless steel meets the conditions that (Cr + Mo +1.5Si)/(Ni +30N +30C +0.25Cu +0.5Mn) is less than or equal to 1.30, and the stainless steel is a full austenite structure at room temperature.

Optionally, the chemical composition of the stainless steel satisfies the following relationship: PREN is Cr +3.3Mo +16N is more than or equal to 27.0, Nb is C is more than or equal to 2.5, and Ca is O is more than or equal to 2.0; wherein the PREN is the pitting resistance equivalent of the stainless steel.

Optionally, the pitting potential of the stainless steel is more than or equal to 500mV, and the pitting weight loss rate of FeCl3 is less than or equal to 0.60g/m 2. h.

Optionally, the stainless steel is cooled to liquid nitrogen-196 ℃ without martensitic transformation, and deformed by 10% at room temperature without martensitic transformation.

In another aspect, the present invention also provides a method for manufacturing the stainless steel, including: smelting according to the chemical components to obtain molten steel, wherein the solubility of nitrogen in the smelting material is more than or equal to the content of nitrogen; reducing the molten steel, wherein the oxygen content is controlled to be less than or equal to 0.0040 percent in the reduction treatment; adding Ca lines or Si-Ca lines into the molten steel after reduction treatment, and controlling the content of Ca: 0.0080-0.0.0120% and the Ca is O more than or equal to 2.0, so that the inclusion in the molten steel is not more than 1.5 grade; casting the molten steel into a casting blank or a bar, wherein the superheat degree is less than or equal to 35 ℃ during casting; forging or hot rolling the casting blank or the bar at the heating temperature of 1160-1250 ℃; and annealing and pickling the forged blank or the bar, wherein the annealing temperature is 1050-1080 ℃.

Optionally, the smelting according to the chemical components to obtain molten steel comprises: adding ferrochrome, ferronickel and waste steel into an electric furnace for melting to obtain molten steel; and pouring the molten steel into an AOD furnace, and performing blowing for removing C, removing S, increasing N and controlling N in the AOD furnace, wherein oxygen blowing and decarburization are performed during smelting, and the carbon content is controlled to be 0.02-0.08%.

The stainless steel and the manufacturing method thereof provided by the invention comprehensively utilize elements such as C, N, Mn, Ni, Cu, Cr and the like to obtain an austenite phase with high stability, and inhibit the occurrence of a thermally induced martensite phase at low temperature or induce martensite transformation under a stress strain condition. The material remains nonmagnetic after low temperature application, processing or forming or stress.

Drawings

FIG. 1 is a flow chart of a method of making stainless steel according to an embodiment of the present invention;

FIG. 2 is a schematic metallographic structure of the sample of example 5 of the present invention after annealing treatment and 30min of heat preservation at room temperature;

FIG. 3 is a schematic diagram of the metallographic structure of the sample obtained in example 5 of the present invention after annealing treatment and heat preservation at-196 deg.C for 30 min.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

As shown in fig. 1, an embodiment of the present invention provides a stainless steel, including:

the chemical components by mass percent are as follows: c, carbon C: 0.02 to 0.08%, Si: 0.2-1.0%, Mn: 2.0-4.0%, Cr: 17.0-18.5%, Ni: 8.0-10.0%, N: 0.12-0.20%, Cu: 1.00-2.00%, molybdenum Mo: 2.1 to 3.3%, niobium Nb: 0.10 to 0.20%, boron B: 0.0015-0.0025%, calcium Ca: 0.0080-0.0120%, less than or equal to 0.0040% of oxygen O, and the balance of Fe and inevitable impurities.

The stainless steel provided by the invention comprehensively utilizes elements such as C, N, Mn, Ni, Cu, Cr and the like to obtain an austenite phase with high stability, and inhibits the occurrence of a thermally induced martensite phase at low temperature or induces martensite phase transformation under a stress strain condition. The material remains nonmagnetic after low temperature application, processing or forming or stress.

Specifically, conventional SUS304 has a thermal martensite start temperature (Ms) of-91.5 ℃ and a stress-induced martensite transformation Md30/50 temperature of 29 ℃; the above two temperature distributions of SUS316 were-157 ℃ and-51 ℃. It can be seen that the thermal martensitic transformation start temperature is higher than the liquid nitrogen temperature, so that there is a risk of the martensitic phase being produced when cooling to low temperatures. In particular, the temperature at which martensitic transformation starts will be higher under the effect of stress or strain.

The invention gives consideration to the non-magnetic property and high corrosion resistance of the material, and compared with the conventional 304 and 316 and the existing non-magnetic stainless steel, the invention has the following advantages: (1) aiming at the requirement of high corrosion resistance environment, the corrosion resistance is improved by comprehensively adjusting N, Mo, Cr and the like, and the content of elements such as Mn and the like which are not beneficial to the corrosion resistance is controlled, wherein the pitting corrosion resistance equivalent PREN of the material is more than or equal to 27.0; (2) meanwhile, carbon is fixed through Nb microalloying, the molten steel is further purified through Ca treatment by controlling the O content in the steel, so that the material has corrosion resistance superior to SUS 316; the material has excellent corrosion resistance, the pitting potential is more than or equal to 500 millivolts (mV), and the pitting weight loss rate is lower than half of SUS 316. (3) The Ms temperature of the material is far lower than the liquid nitrogen temperature, the Md temperature is lower than-110 ℃, the material is cooled to liquid nitrogen-196 ℃ without martensite phase transformation, and the material still keeps a full austenite structure; the material also keeps a fully austenitic structure after the machining deformation of 10 percent or the cutting machining, and the material keeps the nonmagnetic characteristic of a fully annealed state. In the fields of medical treatment, electronics, communication devices and the like, under the conditions of low temperature and the need of cold forming or processing or stress bearing of parts, no magnetism or magnetic conduction is generated, so that no interference is generated on signals. (4) The content of noble metal elements such as Ni, Mo and the like in the material is close to that of SUS316, so that the material has higher cost performance.

Specifically, in designing the above components, the following are mainly considered:

C. n (carbon, nitrogen): carbon and nitrogen are strong austenite forming elements and can replace nickel to a certain extent, so that the austenite formation is promoted, the austenite structure is stabilized, and the Ms and the Md30/50 temperature are obviously reduced. However, when the carbon content is too high, chromium-rich carbides are easily formed, resulting in intergranular corrosion; if the nitrogen content is too high, solidification pores are likely to be generated. Embodiments of the invention may control C: 0.005-0.05%, N: 0.15 to 0.25 percent. Meanwhile, in order to reduce intergranular poor Cr caused by Cr carbide precipitation, Nb: 0.10-0.20% and controlling Nb to be more than or equal to 2.5, wherein Nb and C are combined to form fine NbC, and the corrosion resistance is not adversely affected. In order to avoid material scrap caused by solidification of pores, the solubility of nitrogen is required to be higher than the content of nitrogen, the superheat degree during casting is controlled to be less than or equal to 35 ℃, and pores are avoided through rapid solidification.

Si (silicon): silicon is a ferrite-forming and stabilizing element used for deoxidation during smelting, and accelerates the precipitation of intermetallic phases when the silicon content is too high. Therefore, the content of silicon in the steel is designed to be 0.2-1.0%.

Mn (manganese): manganese is an austenite forming and stabilizing element, and can replace nickel to a certain extent by utilizing manganese to obtain an austenite structure, and the manganese also reduces Ms and Md temperatures and improves the stability of austenite; meanwhile, the solubility of nitrogen can be obviously improved by adding manganese. However, Mn decreases corrosion resistance. Therefore, the content of Mn in the steel is controlled to be 2.0-4.0%.

Cr (chromium): chromium is the most important element for obtaining the corrosion resistance of steel, and higher chromium needs to be added for ensuring good corrosion resistance. However, chromium is a main ferrite forming element, and too high chromium leads to high chromium equivalent of the material, imbalance of nickel-chromium equivalent ratio and occurrence of a magnetic ferrite phase after the material is solidified. The invention controls the ratio of (Cr + Mo +1.5Si)/(Ni +30N +30C +0.25Cu +0.5Mn) to be less than or equal to 1.30. Comprehensively considered, the Cr content in the steel is controlled to be 17.0-18.5%.

Cu (copper): copper is an austenite forming and stabilizing element that can improve the plasticity and corrosion resistance of stainless steel in reducing acids. Too high Cu content is liable to cause hot rolling edge cracking. Therefore, the Cu content in the steel is controlled to be 1.00-2.00%.

Nb (niobium): niobium can improve the purity of molten steel, more importantly, the structure is effectively refined, and fine NbC is separated out by combining with C, N, the adverse effect of carbide formed by combining C and Cr on corrosion resistance is eliminated, and the content is controlled as follows: nb: 0.10-0.20% and controlling Nb to C to be more than or equal to 2.5.

Ca (calcium), O (oxygen): ca improves the purity of the molten steel, can be combined with O in the steel by utilizing higher activity of the Ca, reduces the oxygen level of the material, and improves the mechanical properties of the material, such as corrosion resistance, toughness and the like; o is introduced into the steel raw material or the decarburization process, the content of O is high, the corrosion resistance and the material toughness are reduced, if O is too low, the control difficulty is large, the cost is high, and the content is controlled as follows: ca: 0.0080-0.0120%, less than or equal to 0.0040% of O, and more than or equal to 2.0% of Ca, under the condition, the inclusion in the steel can be effectively controlled not to be more than 1.5 grade.

B (boron): the addition of B is mainly to strengthen the grain boundary binding force in the hot rolling process and improve the hot processing performance of the material; meanwhile, the purity of the molten steel can be improved by B, and the hot working performance and the corrosion resistance are also improved. However, too high a content of B forms compounds of B, which severely reduces the plasticity and toughness of the material. Therefore, the content of B in the invention is controlled to be 0.0015-0.0025%.

Optionally, the chemical composition of the stainless steel further satisfies the following relationship:

Ms＝1305-61.6Ni-41.7Cr-33.3Mn-27.8Si-1667(C+N)≤-350℃；

Accordingly, as shown in fig. 1, an embodiment of the present invention further provides a method for manufacturing a stainless steel provided in the foregoing embodiment, including:

s11, smelting according to the chemical components to obtain molten steel, wherein the solubility of nitrogen in the smelting material is more than or equal to the actual nitrogen content;

s12, reducing the molten steel, wherein the oxygen content is controlled to be less than or equal to 0.0040% in the reduction treatment;

s13, adding Ca lines or Si-Ca lines into the molten steel after reduction treatment, and controlling the content of Ca: 0.0080-0.0.0120% and the Ca is O more than or equal to 2.0, so that the inclusion in the molten steel is not more than 1.5 grade;

s14, casting the molten steel into a casting blank or a bar, wherein the superheat degree is less than or equal to 35 ℃ during casting;

s15, forging or hot rolling the casting blank or the bar, wherein the heating temperature is 1160-1250 ℃;

s16, annealing and acid washing the forging stock or the bar material, wherein the annealing temperature is 1050-1080 ℃.

The stainless steel manufactured by the method comprehensively utilizes elements such as C, N, Mn, Ni, Cu, Cr and the like to obtain an austenite phase with high stability, and inhibits the occurrence of a thermally induced martensite phase at low temperature or induces martensite transformation under a stress strain condition. The material remains nonmagnetic after low temperature application, processing or forming or stress.

Optionally, in step S11, smelting according to the chemical components to obtain molten steel may specifically include:

adding ferrochrome, ferronickel and waste steel into an electric furnace for melting to obtain molten steel;

and pouring the molten steel into an AOD (argon oxygen decarburization) furnace, and carrying out blowing of removing C, removing S, increasing N and controlling N in the AOD furnace, wherein oxygen blowing and decarburization are carried out during smelting, and the carbon content is controlled to be 0.02-0.08%.

The invention is further illustrated by the following examples and figures.

Table 1 shows the compositions of the steels of the examples and comparative examples of the present invention, and table 1 also shows the Ms temperature and the cr-ni equivalence ratio of the steels of the examples and comparative examples of the present invention, which can characterize the stability of austenite; table 2 shows key process parameters and properties of steels for examples of the invention and comparative examples. Comparative example 1 is austenitic stainless steel SUS304 which is most commonly used, and comparative example 2 is austenitic stainless steel SUS316 which is widely used and has excellent corrosion resistance.

The embodiment of the invention takes the production flow of casting after smelting by an electric furnace-AOD and then forging into a bar, a flat steel or hot rolling into a plate coil as an example: adding ferrochrome, ferronickel, waste steel and the like into an electric furnace for melting, pouring molten steel into an AOD furnace after melting down, and performing blowing for removing C, removing S, increasing N and controlling N in the AOD furnace, wherein oxygen is blown for decarburization during smelting, the carbon content is controlled to be 0.02-0.08%, and then, reduction and deoxidation are performed, and the oxygen content in the molten steel is controlled to be less than or equal to 0.0040%. Adding a B wire and a Ca wire (or a Ca-Si wire) before tapping, and controlling the ratio of B: 0.0015-0.0025%, Ca: 0.0080-0.0120%. The components in the steel simultaneously meet the conditions that the ratio of Nb to C is more than or equal to 2.5 and the ratio of Ca to O is more than or equal to 2.0, and then the components are stirred softly to promote the components to be uniform and then cast. The superheat degree is controlled to be less than or equal to 35 ℃ during casting so as to avoid cracks caused by grain growth and air hole defects caused by nitrogen precipitation. The heating temperature in the forging or hot rolling process is controlled to be 1160-1250 ℃, and the temperature range can obtain excellent hot processing performance and avoid edge cracks. The annealing temperature after forging or hot rolling is 1050-1080 ℃, and the material is fully recovered and recrystallized.

And detecting the content of the magnetic conduction martensite phase in different materials by using a magnetometer. The mechanical properties are all taken from finished bars or plates, processed and detected by adopting JIS 13B standard. The mechanical properties of the inventive steels and the comparative steel grades are given in table 2. The pitting potential of the material is detected by GB/T17897-1999, and the detection conditions are as follows: 30 +/-1 ℃; solution: 3.5 percent of NaCl, and deoxidizing for more than 0.5 hour by more than 99.9 percent of high-purity nitrogen; sample preparation: grinding surface-1200 # sandpaper; parameters are as follows: the sweep was performed at a sweep rate of 20mV per minute until the current value increased to 0.1 mA. Analyzing the pitting weight loss rate by using a GB/T17897-1999 stainless steel ferric trichloride pitting corrosion test method, wherein the test conditions are as follows: 35 +/-1 ℃; solution: 100g of FeCl3 is dissolved in 0.05mol/L dilute hydrochloric acid; sample preparation: grinding the raw surface except the original surface to 600# abrasive paper, and removing grease by absolute ethyl alcohol; experiment time: and (5) 24 h. The specific test results are shown in Table 2. As can be seen from the results in Table 2, the pitting potentials of the examples 1-10 of the invention are more than 500mV, which are significantly higher than 315mV of 304 and 405mV of 316; meanwhile, under the same conditions, the pitting weight loss of the materials of the examples 1 to 10 of the invention is lower than 0.60g/m2 & h, and is obviously lower than 5.00g/m2 & h of 304 and 1.20g/m2 & h of 316, which shows that the materials have excellent corrosion resistance. The excellent corrosion resistance of the material is mainly derived from the improvement of corrosion resistance of Cr, Mo, N and the like and the control of elements unfavorable for corrosion resistance of O, Mn and the like, and meanwhile, the Ca treatment and the stabilization of Nb on carbon can avoid the precipitation of chromium carbide is also an important reason for the excellent corrosion resistance of the embodiment of the invention.

Further, Table 2 shows that the Ms temperature of inventive examples 1-10 is lower than-350 ℃ and that the Ms temperature of comparative examples 1 and 2 is-92 ℃ and-157 ℃. After the materials of examples 1-10 of the invention and the materials of comparative examples 1 and 2 were cooled for 30min at the temperature of liquid nitrogen, the contents of hot martensite phases in the materials are shown in Table 2. The austenite structures of the materials of examples 1 to 10 which still maintain 100% after being cooled by liquid nitrogen (fig. 2 is a structural schematic diagram of the metallographic structure after being annealed and then being kept at room temperature for 30min in example 5 of the present invention, and fig. 3 is a structural schematic diagram of the metallographic structure after being annealed and then being kept at liquid nitrogen temperature for 30min in example 5 of the present invention) show that the austenite stability of the material of the present invention is significantly higher than that of the conventional SUS304 in comparative example 1 and that of the SUS316 in comparative example 2. Table 2 also shows that comparative examples 1 and 2 will also produce some amount of martensite phase after room temperature deformation or room temperature processing, while the materials of examples 1-10 of the present invention still maintain 100% austenite phase, further illustrating that the austenite of the material of the present invention has higher stability and can still maintain fully austenitic structure at low temperature or after forming and processing. Generally, the invention provides the austenitic stainless steel with relatively low cost, the material has the characteristic of high stability of the structure, the full austenitic structure is still kept after low temperature, stress or strain and processing, and the nonmagnetic characteristic of the material is maintained; on the other hand, the material is endowed with excellent corrosion resistance through the matching of alloy elements and the control of inclusions. The material is expected to be widely applied in the fields of electronics, communication, medical treatment and the like with higher requirements on tissue stability.

Table 1 units: weight percent of

TABLE 2

TABLE 2

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.

Claims

1. A stainless steel, comprising:

the chemical components by mass percent are as follows: c, carbon C: 0.02 to 0.08%, Si: 0.2-1.0%, Mn: 2.0-4.0%, Cr: 17.0-18.5%, Ni: 8.0-10.0%, N: 0.12-0.20%, Cu: 1.00-2.00%, molybdenum Mo: 2.1 to 3.3%, niobium Nb: 0.10 to 0.20%, boron B: 0.0015-0.0025%, calcium Ca: 0.0080-0.0120%, less than or equal to 0.0040% of oxygen O, and the balance of Fe and inevitable impurities;

the chemical components satisfy the following relationship:

Ms＝1305-61.6Ni-41.7Cr-33.3Mn-27.8Si-1667(C+N)≤-350℃

wherein Ms is the highest temperature at which the stainless steel starts to generate martensitic transformation in the cooling process, and Md is the highest temperature at which the stainless steel is deformed to induce martensitic transformation; the chemical components of the stainless steel meet the condition that (Cr + Mo +1.5Si)/(Ni +30N +30C +0.25Cu +0.5Mn) is less than or equal to 1.30, and the stainless steel is a fully austenitic structure at room temperature;

the stainless steel is cooled to liquid nitrogen-196 ℃ without martensitic transformation, and deformed by 10% at room temperature without martensitic transformation.

2. The stainless steel of claim 1, wherein the stainless steel has a chemical composition satisfying the following relationship: PREN is Cr +3.3Mo +16N is more than or equal to 27.0, Nb is C is more than or equal to 2.5, and Ca is O is more than or equal to 2.0;

wherein the PREN is the pitting resistance equivalent of the stainless steel.

3. The stainless steel according to claim 2, wherein the stainless steel has a pitting potential of 500mV or more and a pitting weight loss rate of FeCl3 of 0.60g/m 2-h or less.

4. A method of manufacturing a stainless steel according to any of claims 1-3, comprising:

smelting according to the chemical components to obtain molten steel, wherein the solubility of nitrogen in the smelting material is more than or equal to the content of nitrogen;

reducing the molten steel, wherein the oxygen content is controlled to be less than or equal to 0.0040 percent in the reduction treatment;

adding Ca lines or Si-Ca lines into the molten steel after reduction treatment, and controlling the content of Ca: 0.0080-0.0.0120% and the Ca is O more than or equal to 2.0, so that the inclusion in the molten steel is not more than 1.5 grade;

casting the molten steel into a casting blank or a bar, wherein the superheat degree is less than or equal to 35 ℃ during casting;

forging or hot rolling the casting blank or the bar at the heating temperature of 1160-1250 ℃;

annealing and acid washing are carried out on the forged blank or the bar, wherein the annealing temperature is 1050-1080 ℃.

5. The method for manufacturing the stainless steel according to claim 4, wherein the smelting according to the chemical components to obtain molten steel comprises:

and pouring the molten steel into an AOD furnace, and performing blowing for removing C, removing S, increasing N and controlling N in the AOD furnace, wherein oxygen blowing and decarburization are performed during smelting, and the carbon content is controlled to be 0.02-0.08%.