阅读说明：本技术 一种2600MPa级超高强度钢及其制备方法 (2600 MPa-grade ultrahigh-strength steel and preparation method thereof ) 是由 刘雄军 王立杰 蒋虽合 吕昭平 王辉 吴渊 蔡明� 袁伟 于 2021-07-08 设计创作，主要内容包括：本发明属于金属材料制备领域,涉及一种2600MPa级超高强度钢及其制备方法。该超高强度钢的化学成分按重量百分比计为：Ni：10％～18％,Co：4％～16％,Mo：3～9％；Al：0.5～6％,余量为铁和不可避免的杂质。根据成分配料冶炼,经锻压,固溶及冷轧热处理工艺(退火、时效),制备得到组织均匀,高密度B2-NiAl金属间化合物为主要强化相及纳米Mo团簇共同强化的马氏体高强钢,本发明的超高强度钢,抗拉强度≥2600MPa、屈服强度≥2250MPa,在飞机起落架、机翼大梁、发动机壳体和高精密传动主承力构件等高端装备上有广泛的应用前景。(The invention belongs to the field of metal material preparation, and relates to 2600 MPa-level ultrahigh-strength steel and a preparation method thereof. The ultrahigh-strength steel comprises the following chemical components in percentage by weight: ni: 10% -18%, Co: 4% -16%, Mo: 3-9%; al: 0.5-6%, and the balance of iron and inevitable impurities. The high-strength steel is prepared by smelting according to component ingredients and through forging, solid solution and cold rolling heat treatment processes (annealing and aging), the martensite high-strength steel with uniform tissues and the high-density B2-NiAl intermetallic compound serving as a main strengthening phase and strengthened together by nano Mo clusters, the tensile strength is more than or equal to 2600MPa, the yield strength is more than or equal to 2250MPa, and the high-strength steel has wide application prospects in high-end equipment such as aircraft landing gears, wing girders, engine housings, high-precision transmission main bearing members and the like.)

1. The 2600MPa ultrahigh-strength steel is characterized by comprising the following chemical components in percentage by weight: ni: 10% -18%, Co: 4% -16%, Mo: 3-9%; al: 0.5-6%, and the balance of iron and inevitable impurities.

2. The 2600MPa ultra high strength steel according to claim 1, wherein said unavoidable impurities comprise: p is less than or equal to 0.003 percent, S is less than or equal to 0.05 percent, N is less than or equal to 0.03 percent, and O is less than or equal to 0.04 percent.

3. The 2600MPa ultra high strength steel of claim 1, further comprising the following chemical composition, in weight percent: nb is less than or equal to 0.2 percent, B is less than or equal to 0.02 percent, Si is less than or equal to 0.1 percent, W is less than or equal to 3 percent, Mn is less than or equal to 4 percent, Ti: 0.4-2%, Cu: less than or equal to 4 percent and C less than 0.01 percent.

4. The 2600MPa ultra-high strength steel of claim 3, wherein said 2600MPa ultra-high strength steel has an alloy content that is: 2-14 wt% of Al + Mn + Cu + Ti, and 30-50 wt% of Ni + Mo + Co + Cu.

5. The 2600MPa ultra high strength steel of claim 1 or 4, further comprising the following chemical components in weight percent: ta is less than or equal to 0.4 percent, Y is less than or equal to 0.6 percent, or one element or a plurality of rare earth elements in La series and Ac series, the total amount is 0-0.6 percent.

6. Method for the preparation of the ultra high strength steel 2600MPa according to any one of claims 1 to 5, in particular comprising the following steps:

s1) weighing the raw materials according to the design components, smelting, and then continuously casting to form a blank or casting to form an ingot;

s2) carrying out solution treatment on the ingot obtained in the step S1) at the temperature of 1000-1300 ℃ for 1-24 h, and then air-cooling to room temperature;

s3) carrying out hot rolling on the cast ingot treated by the S2) at a certain reduction, and carrying out cold rolling treatment to obtain a plate;

s4) carrying out solid solution and recrystallization treatment on the plate obtained in the step S3) at the temperature of 800-1250 ℃ for 5-90 minutes, and then quenching;

s5) carrying out aging treatment on the plate obtained in the step S4) at 400-700 ℃ for 1-72h to obtain the ultrahigh-strength steel.

7. The method of claim 6, wherein the smelting in S1) is performed by a converter, an electric furnace, magnetic levitation or an electric arc furnace.

8. The method according to claim 6, wherein the reduction in S3) is: 4-20% of each pass, and the total deformation amount is 25-75%.

9. The method as claimed in claim 6, wherein the 2600MPa grade ultra-high strength steel has a tensile strength of 2600MPa or more and a yield strength of 2250MPa or more.

10. The 2600 MPa-grade ultrahigh-strength steel prepared by the method of any one of claims 6 to 9 is applied to preparation of landing gears, wing girders, engine housings and high-precision transmission main bearing members of airplanes.

Technical Field

The invention belongs to the field of metal material preparation, and particularly relates to 2600 MPa-level ultrahigh-strength steel and a preparation method thereof.

Background

With the development of the aerospace industry and implementation of national strategies of 'carbon peak reaching and carbon neutralization', the requirement for lightweight of high-end equipment structural parts is more and more urgent, the requirement for strength of ultrahigh-strength steel is higher and higher, and meanwhile, excellent welding performance is required. In the currently applied ultrahigh-strength steels, the AerMet series ultrahigh-strength steel developed by Carpenter company in the United states has the best comprehensive performance, wherein the tensile strength of the AerMet100 steel is about 2000MPa, and steels of AerMet310 and AerMet340 with higher strength are developed on the basis. However, the practical tensile strength of the AerMet340 steel is only 2379MPa, and the urgent requirement of lightweight of a structural part of high-end equipment cannot be met. Therefore, the development of ultra-high strength steel with higher strength is imminent, and is one of the key challenges facing the field of material science. Weldability is one of the key performance indicators for ultra-high strength steel applications. The existing aeromet series ultra-high strength steels have a common disadvantage: the C content is more than 0.23 wt%, resulting in deterioration of the weldability. The sensitivity to cracks after welding tends to be greater, so that the performance of the weldment is poorer, and the welded structural member is not easy to manufacture. Therefore, the development of ultra-high strength steel with low carbon content is urgently needed to meet the urgent demand of high-end equipment structural members for high-performance steel materials.

Disclosure of Invention

The invention discloses 2600 MPa-grade ultrahigh-strength steel and a preparation method thereof, which aim to solve any of the technical problems and other potential problems in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows: a2600 MPa grade ultra-high strength steel, the 2600MPa grade ultra-high strength steel having chemical compositions in weight percent; ni: 10% -18%, Co: 4% -16%, Mo: 3-9%; al: 0.5-6%, and the balance of iron and inevitable impurities.

Further, the inevitable impurities include: p is less than or equal to 0.003 percent, S is less than or equal to 0.05 percent, N is less than or equal to 0.03 percent, and O is less than or equal to 0.04 percent.

Further, the 2600 MPa-grade ultrahigh-strength steel also comprises the following chemical components in percentage by weight: nb is less than or equal to 0.2 percent, B is less than or equal to 0.02 percent, Si is less than or equal to 0.1 percent, W is less than or equal to 3 percent, Mn is less than or equal to 4 percent, Ti: 0.4-2%, Cu: less than or equal to 4 percent and C less than 0.01 percent.

Further, the alloy content in the 2600 MPa-grade ultrahigh-strength steel needs to meet the following requirements: 2-14 wt% of Al + Mn + Cu + Ti, and 30-50 wt% of Ni + Mo + Co + Cu.

Further, the 2600 MPa-grade ultrahigh-strength steel also comprises the following chemical components in percentage by weight: ta is less than or equal to 0.4 percent, Y is less than or equal to 0.6 percent, or one element or a plurality of rare earth elements in La series and Ac series, the total amount is 0-0.6 percent.

Another object of the present invention is to provide a method for preparing the above 2600MPa grade ultra-high strength steel, which specifically comprises the following steps:

s1) weighing the raw materials according to the design components, smelting, and then continuously casting to form a blank or casting to form an ingot;

s2) carrying out solution treatment on the ingot obtained in the step S1) at the temperature of 1000-1300 ℃ for 1-24 h, and then air-cooling to room temperature;

s3) carrying out hot rolling on the cast ingot treated by the S2) at a certain reduction, and carrying out cold rolling treatment to obtain a plate;

s4) carrying out solid solution and recrystallization treatment on the plate obtained in the step S3) at the temperature of 800-1250 ℃ for 5-90 minutes, and then quenching;

s5) carrying out aging treatment on the plate obtained in the step S4) at 400-700 ℃ for 1-72h to obtain the ultrahigh-strength steel.

Further, the smelting in the step S1) adopts a converter, an electric furnace, magnetic suspension or an electric arc furnace.

Further, the rolling reduction in S3) is: 4-20% of each pass, and the total deformation is 25-75%.

Furthermore, the tensile strength of the 2600 MPa-level ultrahigh-strength steel is more than or equal to 2600MPa, and the yield strength is more than or equal to 2250 MPa.

The 2600 MPa-grade ultrahigh-strength steel prepared by the method is applied to preparation of landing gears, wing girders, engine housings and high-precision transmission main bearing members.

The invention has the advantages and beneficial effects that: due to the adoption of the technical scheme, the tensile strength of the ultrahigh-strength steel prepared by the method is more than or equal to 2600MPa, and the yield strength is more than or equal to 2250 MPa. Compared with the traditional ultrahigh-strength steel, the steel grade adopts a high-density ultrafine precipitated phase B2-NiAl and Mo cluster compounding mode to strengthen the high-strength steel and obtain ultrahigh strength. The strengthening phase B2-NiAl has a completely coherent interface and a similar elastic modulus with the matrix, so that the strengthening phase B2-NiAl has a good elastic limit. Because the steel grade has little carbon or no carbon, the steel grade also has excellent welding performance on the premise of keeping the ultrahigh strength. In addition, the steel grade has a certain content of Al, so that the weight of the material can be reduced, and the Al and N can form compact AlN to strengthen the surface of the steel. In conclusion, the steel is ultrahigh-strength steel with highest strength at present, has ultrahigh strength, excellent weldability and processability, and is expected to meet the urgent requirement of lightweight high-end equipment structural parts.

Drawings

Fig. 1 is a schematic drawing of the tensile curve of ultra-high strength steels obtained in examples 2 and 4 of the present invention.

FIG. 2 is a schematic diagram of the distribution of three elements, Ni, Al and Mo, tested by APT in example 1 of the present invention.

FIG. 3 shows B observed by a transmission electron microscope in example 1 of the present invention₂Schematic representation of the NiAl precipitated phases.

Detailed Description

The technical solution of the present invention is further explained with reference to the accompanying drawings and specific embodiments.

The 2600 MPa-grade ultrahigh-strength steel comprises the following chemical components in percentage by weight; ni: 10% -18%, Co: 4% -16%, Mo: 3-9%; al: 0.5-6%, and the balance of iron and inevitable impurities.

The inevitable impurities include: p is less than or equal to 0.003 percent, S is less than or equal to 0.05 percent, N is less than or equal to 0.03 percent, and O is less than or equal to 0.04 percent.

The 2600 MPa-grade ultrahigh-strength steel further comprises the following chemical components in percentage by weight: nb is less than or equal to 0.2 percent, B is less than or equal to 0.02 percent, Si is less than or equal to 0.1 percent, W is less than or equal to 3 percent, Mn is less than or equal to 4 percent, Ti: 0.4-2%, Cu: less than or equal to 4 percent and C less than 0.01 percent.

The alloy content in the 2600 MPa-grade ultrahigh-strength steel needs to meet the following requirements: 2-14 wt% of Al + Mn + Cu + Ti, and 30-50 wt% of Ni + Mo + Co + Cu.

The 2600 MPa-grade ultrahigh-strength steel further comprises the following chemical components in percentage by weight: ta is less than or equal to 0.4 percent, Y is less than or equal to 0.6 percent, or one element or a plurality of rare earth elements in La series and Ac series, the total amount is 0-0.6 percent.

Another object of the present invention is to provide a method for preparing the above 2600MPa grade ultra-high strength steel, which specifically comprises the following steps:

s1) weighing the raw materials according to the design components, smelting, and then continuously casting to form a blank or casting to form an ingot;

s2) carrying out solution treatment on the ingot obtained in the step S1) at the temperature of 1000-1300 ℃ for 1-24 h, and then air-cooling to room temperature;

s3) carrying out hot rolling on the cast ingot treated by the S2) at a certain reduction, and carrying out cold rolling treatment to obtain a plate;

s4) carrying out solid solution and recrystallization treatment on the plate obtained in the step S3) at the temperature of 800-1250 ℃ for 5-90 minutes, and then quenching;

s5) carrying out aging treatment on the plate obtained in S4) at 400-700 ℃ for 1-72h to obtain the super-high strength steel.

And the smelting in the S1) adopts a converter, an electric furnace, magnetic suspension or an electric arc furnace.

The reduction amount in S3) is: 4-20% of each pass, and the total deformation amount is 25-75%.

The tensile strength of the 2600 MPa-grade ultrahigh-strength steel is more than or equal to 2600MPa, and the yield strength is more than or equal to 2250 MPa.

The 2600 MPa-grade ultrahigh-strength steel prepared by the method is applied to preparation of landing gears, wing girders, engine housings and high-precision transmission main bearing members of airplanes.

Example 1:

the raw materials are weighed according to the mixture ratio of the table 1, and smelting and casting are carried out in a high vacuum argon atmosphere electric arc melting furnace. And carrying out solution treatment on the prepared cast ingot at 1200 ℃ for 12h, and then quenching. And cold-rolling the quenched sample by 70% to obtain a plate with a proper thickness, and then processing the plate at the temperature of 1000 ℃ for 80 minutes and at the temperature of 650 ℃ for 60 hours to obtain the sample. The processed samples were subjected to a tensile test on a stretcher to obtain the properties of tables 2 and 4. The samples were examined by APT and TEM, and it was found that NiAl and Mo clusters were present in APT as shown in fig. 2. From the TEM, as shown in fig. 3, we can see that a large amount of NiAl exists.

TABLE 1UHS-1 chemical composition (wt%)

Composition (I)

C

Ni

Mo

Co

Al

Nb

La

Si

By weight%

0

17.69

5

8.10

2.56

0.1

0.002

0.003

Composition (I)

Mn

P

S

Fe

Weight (D)

0.05

0.004

0.003

Balance of

TABLE 2UHS-1 mechanical Properties

σbMPa	σ0.2MPa	％
			2608

Example 2:

the materials were weighed according to the ratios in table 3 and smelted and cast in a converter. And carrying out solution treatment on the prepared cast ingot at 1100 ℃ for 20h, and then quenching. Cold rolling the quenched sample to 50% of a plate with a proper thickness, treating at 800 ℃ for 60 minutes, at 500 ℃ for 72 hours, and subjecting the processed sample to a tensile test on a stretcher to obtain the performance.

TABLE 3UHS-2 chemical composition (wt%)

Composition (I)

C

Ni

Mo

Co

Al

Nb

La

Si

By weight%

0

18.00

9

16

6.00

0.1

0.002

0.003

Composition (I)

Mn

P

S

Fe

Weight (D)

0.05

0.004

0.003

Balance of

TABLE 4UHS-2 mechanical Properties

σbMPa	σ0.2MPa	％
			2608	2290	3.7

Example 3:

the materials were weighed according to the ratios in table 5 and were smelted and cast in a high vacuum argon atmosphere arc melting furnace. And carrying out solution treatment on the prepared cast ingot at 1000 ℃ for 24h, and then quenching. The quenched sample was cold rolled to 75% to a suitable thickness sheet, further treated at 1200 ℃ for 30 minutes at 700 ℃ for 50 hours, and the processed sample was subjected to tensile test on a stretcher to obtain properties.

TABLE 5UHS-3 chemical composition (wt%)

Composition (I)	C	Ni	Mo	Co	Al	Nb	La	Si
									By weight%	0	10	3	4	0.5	0.1	0.002	0.003
Composition (I)	Mn	P	S	Cu	Fe
									Weight (D)	0.05	0.004	0.003	0.6	Balance of

TABLE 6UHS-3 mechanical Properties

Example 4:

the materials were weighed according to the ratios in table 7 and were smelted and cast in a high vacuum argon atmosphere arc melting furnace. And carrying out solution treatment on the prepared cast ingot at 1300 ℃ for 10h, and then quenching. The quenched sample was cold-rolled to 40% to a suitable thickness sheet, further treated at 1000 ℃ for 30 minutes and at 400 ℃ for 68 hours, and the processed sample was subjected to a tensile test on a stretcher to obtain properties and a tensile curve as shown in fig. 1.

TABLE 7UHS-4 chemical composition (wt%)

Composition (I)

C

Ni

Mo

Co

Al

Nb

La

Si

By weight%

0

14

6

11

3.25

0.1

0.002

0.003

Composition (I)

Mn

P

S

Fe

Weight (D)

0.05

0.004

0.003

Balance of

TABLE 8UHS-4 mechanical Properties

σbMPa	σ0.2MPa	％
			2635

Example 5:

the materials were weighed according to the ratios in table 9 and were cast in a high vacuum argon arc melting furnace. And carrying out solution treatment on the prepared cast ingot at 1050 ℃ for 8h, and then quenching. The quenched sample was cold rolled to 30% thickness into a plate of appropriate thickness, further treated at 1250 ℃ for 95 minutes, at 400 ℃ for 72 hours, and the processed sample was subjected to a tensile test on a stretcher to obtain properties.

TABLE 9UHS-5 chemical composition (wt%)

Composition (I)

C

Ni

Mo

Co

Al

Nb

Si

By weight%

0

16

7

14.5

4

0.1

0.003

Composition (I)

Mn

P

S

Fe

Weight (D)

0.05

0.004

0.003

Balance of

TABLE 10UHS-5 mechanical Properties

σbMPa	σ0.2MPa	％
			2602

Example 6:

according to the weight ratio of Ni: 14%, Co: 10%, Mo: 9 percent; al: 3%, Nb is less than or equal to 0.2%, B: 0.02%, Si is less than or equal to 0.1%, W: 3 percent, Mn is less than or equal to 4 percent, La is less than or equal to 0.1 percent, Ti: 2%, Cu: 4 percent, C less than 0.01 percent, and the balance of iron and inevitable impurities. Weighing the materials according to the proportion, and smelting and casting in a high vacuum argon atmosphere magnetic suspension smelting furnace. And carrying out solution treatment on the prepared cast ingot at 1100 ℃ for 20h, and then quenching. The quenched sample is cold-rolled to 50% to a plate with a proper thickness, and then treated at 800 ℃ for 60 minutes and 500 ℃ for 72 hours.

The 2600 MPa-grade ultrahigh-strength steel and the preparation method thereof provided by the embodiment of the application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.