WO2024087545A1

WO2024087545A1 - Device and method for producing carbon-nitrogen synergistic ultrahigh-nitrogen steel by means of multi-furnace pressure casting

Info

Publication number: WO2024087545A1
Application number: PCT/CN2023/089784
Authority: WO
Inventors: 刘吉猛; 王书桓; 赵定国; 宋琼; 张福成
Original assignee: 华北理工大学; 燕山大学
Priority date: 2022-10-24
Filing date: 2023-04-21
Publication date: 2024-05-02
Also published as: CN115592096B; CN115592096A

Abstract

A device for producing a carbon-nitrogen synergistic ultrahigh-nitrogen steel by means of multi-furnace pressure casting. The device comprises a pressurizable steel ladle (22), a pressurizable casting chamber (13) located at the bottom of the steel ladle, and a casting mold (14) provided inside the casting chamber. A tap hole at the bottom of the steel ladle is provided with a three-layer slide gate I (9), and a furnace lid II (18) at the top of the casting chamber is provided with a three-layer slide gate II (11); a high-pressure-resistant pipeline I (20) is connected to a lower sliding plate of the three-layer slide gate I, and a high-pressure-resistant pipeline II (19) is connected to an upper sliding plate of the three-layer slide gate II; and the high-pressure-resistant pipeline I and the high-pressure-resistant pipeline II are connected by means of a multi-furnace conversion joint (10). Further provided is a method for producing a carbon-nitrogen synergistic ultrahigh-nitrogen steel by means of multi-furnace pressure casting. By using the device, high-nitrogen alloy homogenization of molten steel is achieved in the pressurizable steel ladle by performing bottom-blowing nitrogen stirring and increasing the nitrogen pressure; and pressurizing solidification is performed in the casting chamber, and the escaping of nitrogen is inhibited. The pressurizable steel ladle and the pressurizable casting chamber are separately designed, and pressurizing casting of different casting materials in multiple furnaces can be achieved by means of multiple pressurizable casting chambers and multi-furnace conversion joints, thereby improving the production efficiency of a special steel type. The cast ultrahigh-nitrogen steel has a high nitrogen content and uniform components, and can satisfy the corrosion-resistant usage requirements in special environments such as train rails, railroad frogs and ocean engineering.

Description

A device and method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting

Technical Field

The invention belongs to the technical field of ultra-high nitrogen steel casting, and relates to a device and method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting.

Background technique

The application field of ultra-high nitrogen steel has become more and more extensive, especially in wear-resistant steel, steel for train tracks and steel for marine engineering. However, with the development of industry and the needs of the working environment, more stringent requirements are placed on materials. Ultra-high nitrogen steel is divided into high nitrogen high manganese steel and high nitrogen marine engineering steel according to its different uses. Ordinary high manganese steel contains higher carbon, which enhances wear resistance, but has poor corrosion resistance. Reducing the carbon element in high manganese steel, adding nitrogen, and utilizing the carbon-nitrogen synergistic enhancement mechanism can not only improve the wear resistance of the material, but also make it have good corrosion resistance. Marine engineering steel generally uses non-corrosion-resistant ordinary carbon steel, which has a short service life and high replacement cost. Although stainless steel is partially used, the mechanical properties of conventional stainless steel are low and cannot meet the requirements of the complex marine environment.

At present, the industrial production generally contains nitrogen-containing high manganese steel with a nitrogen content of less than 0.2% and nitrogen-containing marine engineering steel with a nitrogen content of less than 0.4%. The effect of nitrogen on improving material performance is not obvious. The main reason is that under normal conditions, nitrogen has to pass through a δ-Fe zone with a particularly low nitrogen solubility during the solidification of molten steel, resulting in low nitrogen content in this type of steel during solidification and prone to defects such as solidification porosity.

At present, there are two main methods to increase the nitrogen content in high nitrogen steel. One is to increase the solidification rate of molten steel, shorten the solidification time of the delta ferrite formation zone during the solidification process, and reduce the escape of nitrogen; the other is to increase the surrounding atmospheric pressure during the solidification of molten steel to form a high-pressure solidification atmosphere. High pressure can reduce the delta ferrite formation area during the solidification process, and even make the delta ferrite area disappear.

Among them, the main ways to increase the solidification rate of molten steel are to add cold steel to the molten steel, use directional solidification or increase the heat exchange between the molten steel and the mold. However, high nitrogen steel generally has a relatively high manganese content, the molten steel shrinks greatly during solidification, and has poor heat dissipation. Excessively high cooling rates can easily lead to increased internal stress in the material and even internal cracks.

However, the main purpose of pressure casting is to provide a suitable environmental pressure during the solidification process of molten steel so that nitrogen can be better dissolved in the steel to increase the nitrogen solubility in high-nitrogen steel; and pressure casting can not only increase the nitrogen content, but also reduce the segregation of nitrogen components, improve the uniformity of material organization, and greatly improve the performance and application range of the material.

Therefore, how to provide a device and method for producing carbon-nitrogen synergistic ultra-high nitrogen steel by multi-furnace pressure casting that can both increase the nitrogen content in high nitrogen steel and improve material properties is a technical problem that technical personnel in this field urgently need to solve.

Summary of the invention

In view of this, the present invention provides a device and method for producing carbon-nitrogen synergistic ultra-high nitrogen steel by multi-furnace pressure casting, which can not only effectively utilize the carbon-nitrogen synergistic mechanism to reduce the carbon in the steel, increase and stabilize the nitrogen content in the steel, and reduce component segregation, but also realize the casting and solidification of ultra-high nitrogen steel with different casting molds in multiple furnaces under pressurized conditions, which is suitable for the industrial production of various castings and improves product performance.

In order to achieve the above object, the present invention provides the following technical solutions:

A multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel, the device comprising a ladle, a casting chamber located at the bottom of the ladle, and a casting mold arranged inside the casting chamber; wherein:

The top of the ladle is provided with a furnace cover, a stopper rod control mechanism is provided inside and a three-layer sliding gate is opened at the bottom of the steel outlet; the upper slide plate of the three-layer sliding gate is connected to the gate at the bottom of the ladle, and the lower slide plate is connected to a high-pressure resistant pipe;

The top of the casting chamber is provided with a furnace cover 2, and the furnace cover 2 is provided with a three-layer sliding water gate 2; The upper slide plate of the three-layer sliding nozzle 2 is connected to the high-pressure resistant pipe 2, and the lower slide plate is connected to the pressure-resistant casting long nozzle;

The casting mold is a cavity structure formed by upper and lower double molds. The top of the casting mold is provided with a plurality of risers and a pouring port, and the pouring port is located below the pressure-resistant casting long nozzle.

Optionally, a furnace cover hanging ring is provided in the center of the furnace cover 1, and a nitrogen pressurizing hole, a pressure relief valve and a pressure gauge are provided on the furnace cover 1.

Optionally, the stopper rod control mechanism can control the lifting and lowering of the stopper rod; and the stopper rod control mechanism includes a base fixedly connected to the inside of the furnace cover, a bracket parallel to the stopper rod Y direction, and a clamp that can be electrically controlled to move in the bracket Y direction.

It should be noted that the stopper rod control mechanism is easy to implement in the field of mechanical control, that is, a linear displacement device in the Y direction. The stopper rod only needs to move up and down, and the displacement is very small to control the flow of molten steel.

Optionally, a bottom blowing hole is provided at the bottom of the ladle, and the ladle and the furnace cover are surrounded by sealing bolts to form a closed furnace chamber.

Furthermore, the ladle is supported by a hollow support platform, and the casting chamber is located at the bottom of the hollow support platform.

Optionally, the furnace cover 2 is provided with a pressure gauge and a pressure relief valve, and the side wall of the casting chamber is provided with pressurized vacuum inlet and outlet holes; and the furnace cover 2 and the casting chamber are surrounded by sealing bolts to form a closed furnace cavity.

Optionally, the high-pressure resistant pipeline 1 is connected to the high-pressure resistant pipeline 2 via a multi-furnace conversion joint.

In addition, the present invention also claims a method for producing carbon-nitrogen synergistic ultra-high nitrogen steel by multi-furnace pressure casting, which is a method for producing carbon-nitrogen synergistic ultra-high nitrogen steel using the above-mentioned device, specifically comprising the following steps:

1) adding the molten steel containing supersaturated nitrogen into the ladle, sealing the ladle with a furnace cover, stirring with bottom blowing nitrogen through the ladle bottom blowing hole and pressurizing with nitrogen through the nitrogen pressurizing hole, The pressure is controlled within the range of 0-6MPa;

2) placing the casting mold into the casting chamber, evacuating the casting chamber to below 10 Pa by pressurizing the vacuum inlet and outlet holes, washing the furnace with nitrogen once, and then vacuumizing and pressurizing with nitrogen until the specified pressure is reached;

3) hoisting the ladle onto the hollow support platform above the casting chamber, and connecting the high-pressure resistant pipe 1 and the high-pressure resistant pipe 2 through a multi-furnace conversion joint;

4) opening the middle slide plate of the three-layer sliding gate 2 to make the pressure in the high-pressure resistant pipeline the same as that in the casting chamber;

5) Open the middle slide of the three-layer sliding gate and control the stopper rod to rise for casting;

6) After the casting is completed, the stopper rod is controlled to descend to seal the water inlet of the ladle, the middle slide plates of the three-layer sliding water inlet 1 and the three-layer sliding water inlet 2 are closed respectively, the multi-furnace conversion joint is opened, the pressure in the casting chamber is always paid attention to so as to perform appropriate pressure replenishment operation, and the ladle is hoisted above another casting chamber for casting of the next casting mold;

7) Maintaining a constant pressure in the casting chamber until the molten steel is completely solidified, opening the pressure relief valve to release air to normal pressure, and then opening the upper cover of the casting chamber, lifting out the casting mold and opening it, thereby obtaining carbon-nitrogen synergistic ultra-high nitrogen steel.

It should be noted that pressurization can increase the dissolved nitrogen content during the casting process, and vacuuming and furnace cleaning can improve the purity of the material.

Furthermore, the composition of the carbon-nitrogen synergistic ultra-high nitrogen steel mainly produced using the above-mentioned casting device is: C 0~0.8%, Si 0~0.5%, Cr 4~20%, Mn 11~20%, N 0.3~1.4%, S 0~0.02%, P 0~0.02%, and the rest is iron.

It can be seen from the above technical solutions that, compared with the prior art, the device and method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting provided by the present invention has the following excellent effects:

The present invention mainly comprises a pressurized ladle, a multi-furnace pressurized casting chamber, a conversion and connection device between the multiple furnaces, and a cast carbon-nitrogen synergistic ultra-high nitrogen steel special steel. In the pressurized ladle, bottom blowing nitrogen stirring and nitrogen pressure are adopted to realize high nitrogen alloy homogenization of molten steel. Pressurized solidification is carried out in the casting chamber to inhibit nitrogen escape, improve element segregation, and greatly enhance the wear resistance and corrosion resistance of the special steel with reduced carbon and increased nitrogen. In addition, the present invention designs the pressurized ladle and the pressurized casting chamber separately. Through multiple pressurized casting chambers and conversion and connection devices, pressurized casting of different casting materials in multiple furnaces can be realized, thereby greatly improving the production efficiency of the special steel.

The ultra-high nitrogen steel cast by the present invention has a high nitrogen content and a uniform composition, and can meet the corrosion-resistant use requirements in special environments such as train tracks, frogs, and marine engineering.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a schematic diagram of the structure of a multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel.

FIG. 2 is a microstructural morphology of nitrogen-containing or high-nitrogen high-manganese steel with a nitrogen content of 0.18% (a) at normal pressure solidification and a nitrogen content of 0.54% (b) at pressurized solidification.

Among them, in Figure 1:

1-furnace cover one; 2-nitrogen pressurizing hole; 3-pressure relief valve; 4-furnace cover lifting ring; 5-pressure gauge; 6-stopper rod control mechanism; 7-sealing bolt; 8-stopper rod; 9-three-layer sliding gate one; 10-multi-furnace conversion joint; 11-three-layer sliding gate one; 12-hollow support platform; 13-casting chamber; 14-casting mold; 15-casting mouth; 16-riser; 17-pressurized vacuum inlet and outlet holes; 18-furnace cover two; 19-high-pressure resistant pipeline two; 20-high-pressure resistant pipeline one; 21-bottom blowing hole of ladle; 22-ladle.

Detailed ways

The technical solutions in the embodiments of the present invention will be described below in combination with the embodiments of the present invention and the accompanying drawings. The present invention is clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

The embodiment of the present invention discloses a device and method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting.

In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

The technical solution of the present invention will be further described below in conjunction with specific embodiments.

Example 1

The carbon-nitrogen coordinated ultra-high nitrogen steel casting device of the present invention is used to cast ultra-high nitrogen steel, and the casting production method is as follows:

1. Add the molten steel containing supersaturated nitrogen into the ladle, cover and seal the ladle, then stir with bottom-blown nitrogen and pressurize the nitrogen to 0.6 MPa and keep the pressure constant.

2. Place the mold into the casting chamber, evacuate the casting chamber to below 10Pa, stop evacuating, fill with nitrogen to normal pressure, evacuate the casting chamber to below 10Pa again, stop evacuating, and pressurize the casting chamber with nitrogen until the pressure reaches 1.2MPa.

3. Hang the ladle onto the support frame above the casting chamber and connect the two high-pressure resistant pipes with a multi-furnace conversion joint.

4. Open the middle slide of the three-layer sliding gate 2 to make the pressure inside the high-pressure resistant pipe the same as that in the casting chamber.

5. Open the middle slide of the three-layer sliding gate and control the stopper rod to rise to carry out casting operations.

6. After casting is completed, control the stopper rod to descend to seal the ladle water inlet and close the three-layer sliding water inlet. Middle slide, close the middle slide of the three-layer sliding gate 2, open the multi-furnace conversion joint between the two high-pressure resistant pipes, always pay attention to the pressure situation in the casting chamber, perform appropriate pressure replenishment operations, and hoist the ladle to the top of another casting chamber for casting of the next mold.

7. Maintain the pressure in the casting chamber at a constant 1.2 MPa until the molten steel is completely solidified. Open the pressure relief valve to release the air to normal pressure, then open the upper cover of the casting chamber, lift out the casting mold, and open the casting mold to obtain ultra-high nitrogen steel. The nitrogen content of the ultra-high nitrogen steel is measured to be 0.38%.

Example 2

1. Add the molten steel containing supersaturated nitrogen into the ladle, cover and seal the ladle, stir with bottom nitrogen, pressurize the nitrogen to 0.7MPa and keep the pressure constant.

2. Place the mold into the casting chamber, evacuate the casting chamber to below 10Pa, stop evacuating, fill with nitrogen to normal pressure, evacuate the casting chamber to below 10Pa again, stop evacuating, and pressurize the casting chamber with nitrogen until the pressure reaches 1.5MPa.

6. After the casting is completed, control the stopper rod to descend to seal the ladle water inlet, close the middle slide of the three-layer sliding water inlet 1, close the middle slide of the three-layer sliding water inlet 2, open the multi-furnace conversion joint between the two high-pressure resistant pipes, always pay attention to the pressure in the casting room, perform appropriate pressure replenishment operations, and hoist the ladle to another The next mold is poured above one casting chamber.

7. Maintain the pressure in the casting chamber at a constant 1.5 MPa until the molten steel is completely solidified. Open the pressure relief valve to release the air to normal pressure, then open the upper cover of the casting chamber, lift out the casting mold, and open the casting mold to obtain ultra-high nitrogen steel. The nitrogen content of the ultra-high nitrogen steel is measured to be 0.54%.

Example 3

2. Place the mold into the casting chamber, evacuate the casting chamber to below 10Pa, stop evacuating, fill with nitrogen to normal pressure, evacuate the casting chamber to below 10Pa again, stop evacuating, and pressurize the casting chamber with nitrogen until the pressure reaches 1.3MPa.

6. After the casting is completed, control the stopper rod to descend to seal the ladle water inlet, close the middle slide of the three-layer sliding water inlet one, close the middle slide of the three-layer sliding water inlet two, open the multi-furnace conversion joint between the two high-pressure resistant pipes, always pay attention to the pressure in the casting chamber, perform appropriate pressure replenishment operations, and hoist the ladle to the top of another casting chamber for casting of the next mold.

7. Keep the pressure in the casting chamber constant at 1.3MPa until the molten steel is completely solidified, and open the pressure relief valve to release air. After reaching normal pressure, the upper cover of the casting chamber is opened, the casting mold is lifted out, and the marine steel can be obtained by opening the casting mold. The nitrogen content of the marine steel is measured to be 1.1%.

Among them, the composition of the carbon-nitrogen synergistic ultra-high nitrogen steel cast by the above-mentioned device and method is shown in Table 1 below:

Table 1

Moreover, the microstructure morphology of the atmospheric solidified high manganese steel with a nitrogen content of 0.18% is shown in FIG2a, and the microstructure of the pressurized solidified high manganese steel with a nitrogen content of 0.54% is shown in FIG2b. The tensile properties are shown in Table 2.

Table 2

Under normal pressure conditions, the nitrogen content of the high manganese steel is generally less than 0.18%, and the nitrogen content of the marine steel is generally less than 0.4%. It can be seen from Table 1 that the nitrogen content of the ultra-high nitrogen steel produced by casting with the pressurized device is very high. Under the conditions of pressure casting and pressurized solidification, the nitrogen content reaches 0.38%, 0.54% and 1.1% respectively. Increasing the nitrogen content in the steel can not only improve the corrosion resistance of the material, but also improve its mechanical properties.

It can be seen from Figures 2a and 2b that increasing the nitrogen content in the steel can refine the cast grains. And from Table 2, compared with ordinary high manganese steel containing 0.18% nitrogen, the yield strength of high manganese steel containing 0.54% nitrogen is increased by 16.02%, the tensile strength is increased by 6.00%, the elongation after fracture is increased by 14.63%, and the shrinkage after fracture is increased by 16.87%, achieving a comprehensive improvement in mechanical properties.

The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but It is to be consistent with the widest scope consistent with the principles and novel features disclosed herein.

Claims

A multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel, characterized in that the device comprises a ladle (22), a casting chamber (13) located at the bottom of the ladle (22), and a casting mold (14) arranged inside the casting chamber (13); wherein:

The top of the ladle (22) is provided with a furnace cover (1), a stopper rod control mechanism (6) is provided inside, and a three-layer sliding gate (9) is opened at the bottom of the steel outlet; the upper slide plate of the three-layer sliding gate (9) is connected to the gate at the bottom of the ladle (22), and the lower slide plate is connected to a high-pressure resistant pipe (20);

A furnace cover 2 (18) is provided on the top of the casting chamber (13), and a three-layer sliding gate 2 (11) is provided on the furnace cover 2 (18); the upper slide plate of the three-layer sliding gate 2 (11) is connected to the high-pressure resistant pipe 2 (19), and the lower slide plate is connected to the long pressure-resistant casting gate;

The casting mold (14) is a cavity structure formed by upper and lower double molds. The top of the casting mold (14) is provided with a plurality of risers (16) and a pouring port (15), and the pouring port (15) is located below the pressure-resistant casting long nozzle.
According to the multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel as described in claim 1, it is characterized in that a furnace cover hanging ring (4) is provided in the center of the furnace cover (1), and a nitrogen pressurizing hole (2), a pressure relief valve (3) and a pressure gauge (5) are provided on the furnace cover (1).
According to the multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel according to claim 1, it is characterized in that the stopper rod control mechanism (6) can control the lifting and lowering of the stopper rod (8); and the stopper rod control mechanism (6) includes a base fixedly connected to the inside of the furnace cover (1), a bracket parallel to the Y direction of the stopper rod (8), and a clamp that can be electrically controlled to move in the Y direction of the bracket.
According to the multi-furnace pressure casting device for producing carbon-nitrogen synergistic ultra-high nitrogen steel as described in claim 1, it is characterized in that a bottom blowing hole (21) is provided at the bottom of the ladle (22), and the ladle (22) and the furnace cover (1) are surrounded by sealing bolts (7) to form a closed furnace chamber.
A method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting according to claim 1 or 4 The device is characterized in that the ladle (22) is supported by a hollow support platform (12), and the casting chamber (13) is located at the bottom of the hollow support platform (12).
According to the multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel as described in claim 1, it is characterized in that a pressure gauge and a pressure relief valve are provided on the second furnace cover (18), and a pressurized vacuum inlet and outlet hole (17) is opened on the side wall of the casting chamber (13); and the second furnace cover (18) and the casting chamber (13) are surrounded by sealing bolts to form a closed furnace cavity.
According to the multi-furnace pressure casting device for producing carbon-nitrogen coordinated ultra-high nitrogen steel as described in claim 1, it is characterized in that the high-pressure resistant pipeline one (20) is connected to the high-pressure resistant pipeline two (19) through a multi-furnace conversion joint (10).
A method for producing carbon-nitrogen coordinated ultra-high nitrogen steel by multi-furnace pressure casting, characterized in that the method for producing ultra-high nitrogen steel using the device as claimed in claim 1 specifically comprises the following steps:

1) adding the molten steel containing supersaturated nitrogen into the ladle (22), sealing the ladle (22) with a furnace cover (1), blowing nitrogen through the ladle bottom blowing hole (21) for stirring, and pressurizing through the nitrogen pressurizing hole (2), wherein the pressure is controlled within the range of 0-6 MPa;

2) placing the casting mold (14) into the casting chamber (13), evacuating the casting chamber (13) to below 10 Pa through the pressurized vacuum inlet and outlet holes (17), then flushing the furnace with nitrogen once, and then applying nitrogen pressure after evacuation until a specified pressure is reached;

3) hoisting the ladle (22) onto the hollow support platform (12) above the casting chamber (13), and connecting the high-pressure resistant pipe 1 (20) and the high-pressure resistant pipe 2 (19) via a multi-furnace conversion joint (10);

4) opening the middle slide plate of the three-layer sliding gate second (11) to make the pressure in the high-pressure resistant pipeline the same as that in the casting chamber (13);

5) Open the middle slide of the three-layer sliding gate (9) and control the stopper rod (8) to rise. casting;

6) After the casting is completed, the stopper rod (8) is controlled to descend to seal the water inlet of the ladle (22), the middle slide plates of the three-layer sliding water inlet 1 (9) and the three-layer sliding water inlet 2 (11) are closed respectively, the multi-furnace conversion joint (10) is opened, and the pressure in the casting chamber (13) is always paid attention to so as to perform appropriate pressure replenishment operations, and the ladle (22) is hoisted above another casting chamber for casting of the next casting mold;

7) Maintaining a constant pressure in the casting chamber (13) until the molten steel is completely solidified, opening the pressure relief valve to release air to normal pressure, and then opening the upper cover of the casting chamber (13), lifting out the casting mold (14) and opening it, thereby obtaining carbon-nitrogen synergistic ultra-high nitrogen steel.
The method for producing carbon-nitrogen synergistic ultra-high nitrogen steel by multi-furnace pressure casting according to claim 8 is characterized in that the components of the produced carbon-nitrogen synergistic ultra-high nitrogen steel are as follows in terms of mass percentage:

C 0～0.8%, Si 0～0.5%, Cr 4～20%, Mn 11～20%, N 0.3～1.4%, S 0～0.02%, P 0～0.02%, and the rest is iron.