A method for preparing a two-stage organization non-magnetic bearing alloy

Abstract

The application discloses a preparation method of a two-stage microstructure non-magnetic bearing alloy, which comprises the following steps: one-time cold drawing of a non-magnetic bearing alloy rod, one-time high-temperature solid solution, two-time cold drawing, two-time high-temperature solid solution, ultra-high frequency induction heating and oil bath. The non-magnetic bearing alloy prepared by the method has excellent comprehensive performance, has a two-stage microstructure composed of a surface layer high-strength microstructure (0.35mm-0.45mm in depth) and a core high-toughness microstructure, the tensile strength of the alloy is 2250MPa-2310MPa, the elongation is 23.6%-26.4%, the impact toughness is 427.2 J / cm 2 -450.1J / cm 2 , and the rotary bending fatigue strength is 1252MPa-1271MPa.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plastic processing and heat treatment of metal materials, and particularly relates to a preparation method of a two-stage structure non-magnetic bearing alloy. BACKGROUND

[0002] Bearing bears complex alternating load in mechanical equipment, and is called as "joint of high-end equipment". As a large country of research and production of bearing materials, China has several categories of bearing materials, such as high-carbon chromium bearing steel, carburizing bearing steel, high-temperature bearing steel, medium-carbon bearing steel and non-magnetic bearing steel. Non-magnetic bearing steel is very important as a branch of bearing materials, and plays a key role in important fields such as aerospace and national defense industry. In recent years, the application space of non-magnetic bearing steel in the field of medical devices and other civilian fields is also getting larger and larger.

[0003] 00Cr40Ni55Al3 is a kind of nickel-based non-magnetic alloy, which has the characteristics of non-magnetic, wear-resistant, corrosion-resistant and high-temperature-resistant. The processing performance of the alloy is excellent under solid solution condition, and after aging treatment, the surface hardness is as high as 62HRC due to the precipitation hardening effect of γ´ phase and α-Cr phase in the structure, which can meet the performance requirements of bearing materials under the service conditions of non-magnetic, vacuum and self-lubrication at high temperature of 300℃ to 500℃. However, due to the high surface hardness of the alloy after aging treatment, the plasticity is poor, the charpy impact toughness is less than 20J / cm 2 , and the rotating bending fatigue strength is less than 1000MPa, which cannot meet the increasingly stringent technical requirements of key non-magnetic bearings in aerospace. Achieving the balance between strength and toughness of non-magnetic alloy will become a key measure to further improve the fatigue performance of the material and realize good application in the field of non-magnetic bearings.

[0004] The traditional methods for achieving the balance between strength and toughness of bearing steel mainly include:

[0005] (1) Microstructure refinement: according to the Hall-Petch formula, the strength, plasticity and toughness of the steel can be improved by greatly refining the grains and second phases such as carbides; typical technical means include cyclic quenching, recrystallization heat treatment and multi-directional upsetting.

[0006] (2) Surface strengthening: the plasticity of the steel is improved by reducing the carbon content in the matrix, and then the surface layer is strengthened by surface carburizing, nitriding or carbonitriding, so that the surface layer has a higher content of strengthening elements than the core, and the surface layer has high strength and high hardness, and the core has high plasticity; typical representatives include M50NiL and CSS-42L.

[0007] (3) Induction quenching: the surface layer of the steel is fully quenched by the skin effect of high-frequency induction heating, and the strength decreases and the plasticity increases from the surface layer to the core.

[0008] The technical means of the above-mentioned typical bearing steel strength and toughness balance can well realize the substantial improvement of the fatigue performance of the steel material, but since the 00Cr40Ni55Al3 non-magnetic alloy is a nickel-based alloy, the strengthening mechanism thereof is different from that of the traditional bearing steel, mainly relying on the precipitation strengthening of the second phase such as intermetallic compound and alpha-Cr, and there is no solid-state matrix phase change, which cannot realize the refinement of the structure through phase change, and cannot realize the martensite transformation through quenching, and the fatigue strength of the 00Cr40Ni55Al3 non-magnetic bearing alloy cannot be improved by simply using the traditional technical means. Therefore, it is urgent to adopt innovative technical means to realize the good balance of the strength and toughness of the non-magnetic bearing alloy 00Cr40Ni55Al3, and then obtain excellent fatigue performance. SUMMARY

[0009] The purpose of the present application is to provide a preparation method of a two-stage structure non-magnetic bearing alloy, which has a two-stage microstructure composed of a surface layer high-strength structure (depth 0.35mm-0.45mm) and a core high-toughness structure, and can simultaneously obtain high strength and high toughness, and the rotating fatigue strength is also significantly improved.

[0010] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0011] A preparation method of a two-stage structure non-magnetic bearing alloy, comprising one-time cold drawing of a non-magnetic bearing alloy bar, one-time high-temperature solid solution, two-time cold drawing, two-time high-temperature solid solution, ultra-high frequency induction heating, and oil bath.

[0012] Further, the one-time cold drawing of the present application: the non-magnetic bearing alloy bar is subjected to 5-8 passes of cold drawing processing, and the total cold drawing surface reduction is 36%-68%. By subjecting the non-magnetic bearing alloy bar to large deformation cold drawing processing, the microstructure of the non-magnetic bearing alloy can be fiberized, and a large amount of deformation energy can be stored in the matrix structure, which can lay a foundation for obtaining uniform and fine microstructure on the one hand, and promote the resolubilization of the large particle second phase alpha-Cr in the bar in the subsequent solid solution process on the other hand, thereby reducing the pinning of the grain boundary.

[0013] Further, the one-time high-temperature solid solution of the present application: the cold-drawn non-magnetic bearing alloy bar obtained by one-time cold drawing is heated to 1180℃-1250℃, and held for 60 minutes-120 minutes, and then water-cooled to room temperature. This operation can make the second phase such as alpha-Cr in the cold-drawn material fully resolubilize, and at the same time realize the recrystallization of the cold-deformed fibrous matrix structure and the uniform growth of the grain structure.

[0014] Further, the secondary cold-drawing of the present application: the solid solution state non-magnetic bearing alloy bar obtained by primary solid solution is processed by one pass cold-drawing, and the cold-drawing surface reduction is 6%~12%. By taking a smaller deformation, the cold deformation of the near-surface layer of the bar is realized, while the core region has almost no significant deformation. The difference in the structure is that the surface layer has fibrous structure, and the core has coarse equiaxed grains.

[0015] Further, the secondary high-temperature solid solution of the present application: the cold-drawing state non-magnetic bearing alloy bar obtained by secondary cold-drawing is heated to 1180℃~1250℃, and is kept for 30 minutes~60 minutes, and is water-cooled to room temperature. By taking short-time high-temperature solid solution, the recrystallization of the surface layer fibrous cold-deformation structure can be realized without grain growth, while the coarse equiaxed grains in the core are further grown, and thus the double-level structure of the surface layer fine grains and the core coarse grains is obtained.

[0016] Further, the ultra-high frequency induction heating of the present application: the solid solution state non-magnetic bearing alloy bar obtained by secondary high-temperature solid solution is placed in a high-frequency induction heating system for ultra-high frequency induction heating, the frequency is 1200KHz~2000kHz, the heating temperature is 550℃~700℃, and the holding time is 10 seconds~15 seconds. By means of the skin effect (δ=500×f-0.5, δ is the heating layer, and f is the frequency) of the ultra-high frequency induction heating, the aging hardening of the surface layer structure of a certain depth is realized, while the structure of the core still maintains the solid solution state coarse grain structure. This step forms the final double-level microstructure.

[0017] Further, the oil bath of the present application: the non-magnetic bearing alloy bar obtained after the ultra-high frequency induction heating is rapidly immersed in a quenching oil pool and cooled to room temperature. The purpose of this operation is to reduce the thermal stress generated due to the temperature difference between the surface layer and the core.

[0018] The non-magnetic bearing alloy of the present application is 00Cr40Ni55Al3, and the mass fraction of the chemical elements satisfies: C≤0.03%, Si≤0.15%, Mn≤0.15%, Cr: 39.00%~41.00%, Al: 2.75%~3.15%, and the balance is Ni and inevitable impurities.

[0019] As a preferred, the chemical composition and mass percentage of the non-magnetic bearing alloy of the present application are: C: 0.011%, Si: 0.048%, Mn: 0.012%, Cr: 40.09%, Al: 2.98%, Ni: 56.85%, and the balance is inevitable impurities.

[0020] The non-magnetic bearing alloy prepared by the method of the present application has a double-level microstructure composed of surface layer high-strength structure and core high-toughness structure; and the depth of the surface layer high-strength structure is 0.35mm~0.45mm.

[0021] The tensile strength of the non-magnetic bearing alloy prepared by the method is 2250MPa-2310MPa, the elongation is 23.6%-26.4%, the impact toughness is 427.2 J / cm 2 -450.1J / cm 2 , and the rotating bending fatigue strength is 1252MPa-1271MPa.

[0022] The beneficial effects of the technical scheme of the application are as follows:

[0023] Based on the basic principles of recrystallization kinetics and second phase precipitation kinetics, the two-stage microstructure non-magnetic bearing alloy regulation and control technology is innovatively designed by combining cold working, high-temperature solid solution and ultra-high frequency induction quenching, and the obtained non-magnetic bearing alloy has excellent comprehensive performance, has a two-stage microstructure composed of a high-strength surface layer (depth 0.35mm-0.45mm) and a high-toughness core, the tensile strength of the alloy is 2250MPa-2310MPa, the elongation is 23.6%-26.4%, the impact toughness is 427.2 J / cm 2 -450.1J / cm 2 , and the rotating bending fatigue strength is 1252MPa-1271MPa. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a metallographic photo of the two-stage microstructure non-magnetic bearing alloy of Example 1 (magnification 13 times);

[0025] Figure 2 It is a metallographic photo of the high-strength microstructure of the two-stage microstructure non-magnetic bearing alloy of Example 1 (magnification 500 times);

[0026] Figure 3 It is a metallographic photo of the high-toughness microstructure of the two-stage microstructure non-magnetic bearing alloy of Example 1 (magnification 500 times). DETAILED DESCRIPTION

[0027] The application will be further described in detail below in combination with examples.

[0028] The non-magnetic bearing alloy rods used in each example are prepared by adopting the "vacuum induction + vacuum consumable" smelting φ300mm*700mm specification ingot, and the chemical composition is: C: 0.011%, Si: 0.048%, Mn: 0.012%, Cr: 40.09%, Al: 2.98%, Ni: 56.85%, and the balance is inevitable impurities. In each example, it will not be repeated. Example 1

[0029] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operation is as follows:

[0030] (1) One cold drawing: the non-magnetic bearing alloy rod is subjected to 5 passes of cold drawing, and the total cold drawing surface reduction is 36%;

[0031] (2) One high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1180℃, kept for 60 minutes, and water-cooled to room temperature;

[0032] (3) Two cold drawing: the solid-solution non-magnetic bearing alloy rod obtained in step (2) is subjected to 1 pass of cold drawing, and the cold drawing surface reduction is 6%;

[0033] (4) Two high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1180℃, kept for 30 minutes, and water-cooled to room temperature;

[0034] (5) Ultra-high frequency induction heating: the solid-solution non-magnetic bearing alloy rod obtained in step (4) is placed in a high-frequency induction heating system, subjected to ultra-high frequency induction heating, the frequency is 1200KHz, the heating temperature is 550℃, and the holding time is 10 seconds;

[0035] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool and cooled to room temperature.

[0036] The tensile strength, elongation, charpy impact toughness, and rotary bending fatigue strength of the two-stage structure non-magnetic bearing alloy prepared in this embodiment are shown in Table 1. Example 2

[0037] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operation is as follows:

[0038] (1) One cold drawing: the non-magnetic bearing alloy rod is subjected to 8 passes of cold drawing, and the total cold drawing surface reduction is 68%;

[0039] (2) One high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1250℃, kept for 120 minutes, and water-cooled to room temperature;

[0040] (3) Two cold drawing: the solid-solution non-magnetic bearing alloy rod obtained in step (2) is subjected to 1 pass of cold drawing, and the cold drawing surface reduction is 12%;

[0041] (4) Two high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1250℃, kept for 60 minutes, and water-cooled to room temperature;

[0042] (5) Ultra-high frequency induction heating: the solid solution state non-magnetic bearing alloy rod obtained in step (4) is placed in a high frequency induction heating system, and ultra-high frequency induction heating is performed, the frequency is 2000 kHz, the heating temperature is 700 ℃, and the holding time is 15 seconds;

[0043] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool and cooled to room temperature.

[0044] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 3

[0045] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operations are as follows:

[0046] (1) One cold drawing: the non-magnetic bearing alloy rod is subjected to 7 passes of cold drawing, and the total cold drawing area reduction is 50%;

[0047] (2) One high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1200 ℃, held for 90 minutes, and water-cooled to room temperature;

[0048] (3) Two cold drawing: the solid solution state non-magnetic bearing alloy rod obtained in step (2) is subjected to 1 pass of cold drawing, and the cold drawing area reduction is 10%;

[0049] (4) Two high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1200 ℃, held for 45 minutes, and water-cooled to room temperature;

[0050] (5) Ultra-high frequency induction heating: the solid solution state non-magnetic bearing alloy rod obtained in step (4) is placed in a high frequency induction heating system, and ultra-high frequency induction heating is performed, the frequency is 1800 kHz, the heating temperature is 600 ℃, and the holding time is 13 seconds;

[0051] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool and cooled to room temperature.

[0052] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 4

[0053] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operations are as follows:

[0054] (1) One cold drawing: the non-magnetic bearing alloy bar is subjected to 5 passes of cold drawing processing, and the total cold drawing surface reduction is 68%;

[0055] (2) One high temperature solid solution: the cold-drawn non-magnetic bearing alloy bar obtained in step (1) is heated to 1180℃, and kept for 120 minutes, and then water-cooled to room temperature;

[0056] (3) Two cold drawing: the solid-solution non-magnetic bearing alloy bar obtained in step (2) is subjected to 1 pass of cold drawing processing, and the cold drawing surface reduction is 6%;

[0057] (4) Two high temperature solid solution: the cold-drawn non-magnetic bearing alloy bar obtained in step (3) is heated to 1180℃, and kept for 60 minutes, and then water-cooled to room temperature;

[0058] (5) Ultra-high frequency induction heating: the solid-solution non-magnetic bearing alloy bar obtained in step (4) is placed in a high-frequency induction heating system, and subjected to ultra-high frequency induction heating, the frequency is 1200KHz, the heating temperature is 700℃, and the holding time is 15 seconds;

[0059] (6) Oil bath: the non-magnetic bearing alloy bar obtained in step (5) is rapidly immersed in a quenching oil pool and cooled to room temperature.

[0060] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the two-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 5

[0061] The non-magnetic bearing alloy bar is sequentially subjected to one cold drawing, one high temperature solid solution, two cold drawing, two high temperature solid solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operation is as follows:

[0062] (1) One cold drawing: the non-magnetic bearing alloy bar is subjected to 8 passes of cold drawing processing, and the total cold drawing surface reduction is 36%;

[0063] (2) One high temperature solid solution: the cold-drawn non-magnetic bearing alloy bar obtained in step (1) is heated to 1250℃, and kept for 60 minutes, and then water-cooled to room temperature;

[0064] (3) Two cold drawing: the solid-solution non-magnetic bearing alloy bar obtained in step (2) is subjected to 1 pass of cold drawing processing, and the cold drawing surface reduction is 12%;

[0065] (4) Two high temperature solid solution: the cold-drawn non-magnetic bearing alloy bar obtained in step (3) is heated to 1250℃, and kept for 30 minutes, and then water-cooled to room temperature;

[0066] (5) Ultra-high frequency induction heating: the solid-solution non-magnetic bearing alloy bar obtained in step (4) is placed in a high-frequency induction heating system, and subjected to ultra-high frequency induction heating, the frequency is 2000kHz, the heating temperature is 550℃, and the holding time is 10 seconds;

[0067] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool to cool to room temperature.

[0068] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 6

[0069] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultrahigh frequency induction heating, and oil bath treatment, and the specific operations are as follows:

[0070] (1) One cold drawing: the non-magnetic bearing alloy rod is subjected to 5 passes of cold drawing, with a total cold drawing area reduction of 50%;

[0071] (2) One high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1250°C, held for 90 minutes, and water-cooled to room temperature;

[0072] (3) Two cold drawing: the solid-solution state non-magnetic bearing alloy rod obtained in step (2) is subjected to one pass of cold drawing, with a cold drawing area reduction of 10%;

[0073] (4) Two high-temperature solid solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1180°C, held for 45 minutes, and water-cooled to room temperature;

[0074] (5) Ultrahigh frequency induction heating: the solid-solution state non-magnetic bearing alloy rod obtained in step (4) is placed in a high-frequency induction heating system for ultrahigh frequency induction heating, with a frequency of 1800 kHz, a heating temperature of 550°C, and a holding time of 15 seconds;

[0075] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool to cool to room temperature.

[0076] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 7

[0077] The non-magnetic bearing alloy rod is sequentially subjected to one cold drawing, one high-temperature solid solution, two cold drawing, two high-temperature solid solution, ultrahigh frequency induction heating, and oil bath treatment, and the specific operations are as follows:

[0078] (1) One cold drawing: the non-magnetic bearing alloy rod is subjected to 8 passes of cold drawing, with a total cold drawing area reduction of 50%;

[0079] (2) First high temperature solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1180℃, and kept for 90 minutes, and then water-cooled to room temperature;

[0080] (3) Second cold-drawing: the solution-treated non-magnetic bearing alloy rod obtained in step (2) is cold-drawn for one pass, and the cold-drawing surface reduction is 12%;

[0081] (4) Second high temperature solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1250℃, and kept for 45 minutes, and then water-cooled to room temperature;

[0082] (5) Ultra-high frequency induction heating: the solution-treated non-magnetic bearing alloy rod obtained in step (4) is placed in a high frequency induction heating system, and subjected to ultra-high frequency induction heating, the frequency is 2000 kHz, the heating temperature is 600℃, and the holding time is 10 seconds;

[0083] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool and cooled to room temperature.

[0084] The tensile strength, elongation, charpy impact toughness and rotary bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in this example are shown in Table 1. Example 8

[0085] The non-magnetic bearing alloy rod is sequentially subjected to first cold-drawing, first high temperature solution, second cold-drawing, second high temperature solution, ultra-high frequency induction heating, and oil bath treatment, and the specific operations are as follows:

[0086] (1) First cold-drawing: the non-magnetic bearing alloy rod is cold-drawn for 5 passes, and the total cold-drawing surface reduction is 36%;

[0087] (2) First high temperature solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (1) is heated to 1250℃, and kept for 120 minutes, and then water-cooled to room temperature;

[0088] (3) Second cold-drawing: the solution-treated non-magnetic bearing alloy rod obtained in step (2) is cold-drawn for one pass, and the cold-drawing surface reduction is 12%;

[0089] (4) Second high temperature solution: the cold-drawn non-magnetic bearing alloy rod obtained in step (3) is heated to 1250℃, and kept for 60 minutes, and then water-cooled to room temperature;

[0090] (5) Ultra-high frequency induction heating: the solution-treated non-magnetic bearing alloy rod obtained in step (4) is placed in a high frequency induction heating system, and subjected to ultra-high frequency induction heating, the frequency is 1200 kHz, the heating temperature is 600℃, and the holding time is 15 seconds;

[0091] (6) Oil bath: the non-magnetic bearing alloy rod obtained in step (5) is quickly immersed in a quenching oil pool and cooled to room temperature.

[0092] The tensile strength, elongation, charpy impact toughness and rotating bending fatigue strength of the dual-stage structure non-magnetic bearing alloy prepared in the embodiment are shown in Table 1.

[0093] Table 1 Properties of non-magnetic bearing alloys in various embodiments

[0094]

[0095] The low-magnification microstructure morphology of the dual-stage structure non-magnetic bearing alloy prepared in Embodiment 1 is shown in FIG. 1, which is composed of high-strength surface layer and high-toughness core. Figure 1 As shown in FIG. 2, the high-magnification microstructure morphology of the high-strength surface layer of the dual-stage structure non-magnetic bearing alloy is composed of ultra-fine grains below 10 μm and nanoscale second phase precipitates. Figure 1 As shown in FIG. 3, the high-magnification microstructure morphology of the high-toughness core of the dual-stage structure non-magnetic bearing alloy is composed of solid solution grains of 30 μm to 60 μm and residual second phase precipitates of 5 μm to 10 μm. Figure 2 Figure 3

[0096] Figures 1-3 The strength and toughness mechanism of the dual-stage structure non-magnetic bearing alloy prepared by the method of the present application is explained, that is, the high-strength surface layer obtains high-strength structure by the composite strengthening mechanism of "grain refinement + second phase precipitation" to realize high strength of the surface layer, and the core obtains higher toughness by forming "coarse grains + residual large-grained second phase" solid solution structure. The dual-stage structure of high-strength surface layer and high-toughness core is beneficial to the prepared non-magnetic bearing alloy to have high strength and high toughness, and further to have good fatigue strength.

[0097] The metallographic photos of the dual-stage structure non-magnetic bearing alloys in the remaining embodiments, the high-strength structure in the dual-stage structure and the high-toughness structure in the dual-stage structure are the same as those in Embodiment 1, and are not repeated.

[0098] The above embodiments are only used to illustrate but not to limit the technical solutions of the present application. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or partial replacement should be covered in the scope of the claims of the present application.​​

Claims

1. A method for preparing a bipolar nonmagnetic bearing alloy, characterized in that, This includes one-time cold drawing, one-time high-temperature solution treatment, two-time cold drawing, two-time high-temperature solution treatment, ultra-high frequency induction heating, and oil bath for non-magnetic bearing alloy bars; The ultra-high frequency induction heating: the solid solution non-magnetic bearing alloy rod obtained by secondary high temperature solid solution is placed in the high frequency induction heating system for ultra-high frequency induction heating, with a frequency of 1200kHz~2000kHz, a heating temperature of 550℃~700℃, and a holding time of 10 seconds~15 seconds. The non-magnetic bearing alloy is 00Cr40Ni55Al3, and its chemical element mass fractions meet the following requirements: C≤0.03%, Si≤0.15%, Mn≤0.15%, Cr: 39.00%~41.00%, Al: 2.75%~3.15%, with the balance being Ni and unavoidable impurities; The dual-level structure consists of a high-strength surface layer and a high-toughness core layer.

2. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The first cold drawing: The non-magnetic bearing alloy bar is subjected to 5 to 8 cold drawing processes, with a total cold drawing surface shrinkage rate of 36% to 68%.

3. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The first high-temperature solution treatment involves heating the cold-drawn non-magnetic bearing alloy bar obtained from the first cold drawing to 1180℃~1250℃, holding it at that temperature for 60 minutes~120 minutes, and then water-cooling it to room temperature.

4. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The secondary cold drawing: The solution-treated non-magnetic bearing alloy bar obtained from the first solution treatment is subjected to one cold drawing process, with a cold drawing surface shrinkage rate of 6% to 12%.

5. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The secondary high-temperature solution treatment involves heating the cold-drawn non-magnetic bearing alloy bar obtained from the secondary cold drawing to 1180℃~1250℃, holding it at that temperature for 30 minutes~60 minutes, and then water-cooling it to room temperature.

6. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The oil bath: The non-magnetic bearing alloy bar obtained after ultra-high frequency induction heating is rapidly immersed in a quenching oil bath to cool to room temperature.

7. The method for preparing a bipolar nonmagnetic bearing alloy according to claim 1, characterized in that, The non-magnetic bearing alloy prepared by the method has a tensile strength of 2250 MPa to 2310 MPa, an elongation of 23.6% to 26.4%, and an impact toughness of 427.2 J / cm. 2 ~450.1 J / cm 2 Rotational bending fatigue strength is 1252MPa~1271MPa.

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