Non-magnetic aluminum bronze alloy, non-magnetic aluminum bronze retaining ring and preparation method of non-magnetic aluminum bronze alloy

Abstract

The invention relates to the technical field of copper alloys, in particular to a non-magnetic aluminum bronze alloy, a non-magnetic aluminum bronze retaining ring and a preparation method of the non-magnetic aluminum bronze retaining ring. The invention discloses a preparation method of a non-magnetic aluminum bronze retaining ring. The preparation method comprises the following steps: S1, smelting and casting a non-magnetic aluminum bronze alloy to obtain an aluminum bronze alloy ingot; s2, the aluminum bronze alloy cast ingot is subjected to hot forging treatment, and a sectional material is obtained; and S3, the profile obtained in the step S2 is subjected to solution treatment and aging treatment, and the non-magnetic aluminum bronze retaining ring is obtained. The mechanical property of the aluminum bronze retaining ring is improved by designing deformation and heat treatment processes and adjusting process steps and process parameters, cracks are avoided in the whole preparation process, and large-scale production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloys, and in particular to a non-magnetic aluminum bronze alloy, a non-magnetic aluminum bronze guard ring and a preparation method thereof. Background Art

[0002] The motor rotor retaining ring is an important component in the motor rotor assembly. Its main function is to fix the position of the rotor and prevent the rotor from axial or radial displacement during the operation of the motor. The retaining ring is heat-shrink-fitted on the end ring and is subject to tight fit force, centrifugal force of itself and the end of the winding, bending stress, etc., and the superimposed stress is very high. In order to reduce the temperature rise of the rotor and reduce the fracture of the rotor end, the retaining ring material is required to have high strength, toughness, good thermal conductivity and stress corrosion resistance. At the same time, in order to reduce magnetic leakage and eddy current losses, the retaining ring material must be non-magnetic.

[0003] At present, the commonly used material for retaining rings is high manganese non-magnetic steel. Due to its good mechanical properties, it was once used as the retaining ring material for large generators. However, when there is a corrosive medium (including ordinary water) in the working environment, stress corrosion cracking is prone to occur. Therefore, the development of a non-magnetic metal retaining ring material with high tensile strength, yield strength and corrosion resistance has become the current research direction.

[0004] Aluminum bronze is one of the most ideal non-magnetic metal materials. It has high strength, high hardness, high wear resistance and good corrosion resistance. It also has the characteristics of simple process, low cost and stable structure. Therefore, aluminum bronze is feasible as a retaining ring material; however, problems such as segregation and cracks often occur during the production of aluminum bronze retaining rings, which is not conducive to large-scale production.

[0005] Chinese patent CN106048296A discloses a high-strength and high-toughness Cu-Al-Fe-Ni-RE material for a guard ring and a preparation method thereof. The aluminum bronze guard ring is prepared by a "vacuum melting + pressurized solidification + heat treatment" process. However, this method has the following limitations:

[0006] (1) The deformation during the preparation process is small, the grain size of the alloy prepared later is relatively large, and the strength of the aluminum bronze alloy is relatively low;

[0007] (2) The aging heat treatment temperature is too high, the grain size of the alloy prepared later is too large, and the strength of the aluminum bronze alloy is too low. Summary of the invention

[0008] In order to solve the above technical problems existing in the prior art, the present invention provides a non-magnetic aluminum bronze alloy, a non-magnetic aluminum bronze guard ring and a preparation method thereof.

[0009] The technical solution of the present invention to solve the above technical problems is as follows:

[0010] The first aspect of the present invention is to provide a non-magnetic aluminum bronze alloy, which comprises the following components by weight percentage: Al 10.0-12.0wt%, Fe 6.0-8.0wt%, Ni 6.0-8.0wt%, and the balance is copper and inevitable impurities.

[0011] The above non-magnetic aluminum bronze alloy is used to improve the mechanical properties and corrosion resistance of the alloy by limiting the content of each element. A small amount of iron can be dissolved in the α solid solution of aluminum bronze, but when the iron content is too high, it will cause the needle-shaped FeAl in the β phase. 3 The formation of, thereby reducing the mechanical properties and corrosion resistance of the alloy; the addition of nickel can improve the strength, hardness, thermal stability and corrosion resistance of the aluminum bronze alloy, and nickel can also change the morphology of the α phase in the alloy from needle-like to lamellar, and the performance of the aluminum bronze alloy can be improved by adjusting the nickel content; the increase of Al elements can improve the strength, hardness and wear resistance of the alloy; through the combination of the above three elements and their contents, the performance of the aluminum bronze alloy is improved, and a non-magnetic aluminum bronze alloy that can be used for subsequent deformation and heat treatment is obtained, which can be used for the preparation of high-performance guard rings.

[0012] The second aspect of the present invention is to provide a non-magnetic aluminum bronze guard ring, which is prepared using the non-magnetic aluminum bronze alloy mentioned above.

[0013] Another aspect of the present invention is to provide a method for preparing a non-magnetic aluminum bronze guard ring, comprising the following steps:

[0014] S1, melting and casting the non-magnetic aluminum bronze alloy to obtain an aluminum bronze alloy ingot;

[0015] S2, subjecting the aluminum-bronze alloy ingot to a hot forging treatment to obtain a profile;

[0016] S3, subjecting the profile obtained in step S2 to solution treatment and aging treatment to obtain a non-magnetic aluminum bronze guard ring.

[0017] On the basis of the above technical solution, the present invention can also make the following improvements:

[0018] Furthermore, in step S1, a vacuum melting process is adopted to place the non-magnetic aluminum-bronze alloy in a vacuum melting furnace to obtain an aluminum-bronze alloy ingot.

[0019] The beneficial effect of adopting the above further technical solution is to ensure the stability of the composition and phase in the aluminum bronze alloy ingot.

[0020] Furthermore, in step S2, the hot forging treatment includes roughening and hole expansion.

[0021] The beneficial effect of adopting the above-mentioned further technical solution is: increasing the deformation amount. After roughening and hole expansion, the deformation amount is 60%-80%, thereby improving the mechanical properties of the finished aluminum bronze guard ring. If the deformation amount is too small, the mechanical properties of the finished aluminum bronze guard ring cannot meet the requirements. If the deformation amount is too large, it will cause the generation and expansion of cracks.

[0022] Furthermore, in step S2, the temperature of the thermal calcination treatment is 800-950°C, the holding time is 3-6h, and the final calcination temperature is ≥650°C.

[0023] The beneficial effect of adopting the above-mentioned further technical solution is that by controlling the hot forging temperature and the final forging temperature, the fluidity and variability of the metal billet are improved, thereby reducing the roughness of the product surface and the occurrence of defects such as internal pores. If the final forging temperature is lower than 650°C, the fluidity and variability of the metal billet will deteriorate, resulting in defects such as rough product surface or internal pores.

[0024] Furthermore, in step S3, the temperature of the solution treatment is 850°C-950°C, and the solution treatment time is 1-4h.

[0025] The beneficial effect of adopting the above further technical solution is that as the solution temperature increases within the range of 850-900°C, more K phase-intermetallic compounds (Al-Fe-Ni) dissolve into the matrix, resulting in more matrix alloy elements, and the generated β phase (Cu 3 The more Al-based solid solution), the more martensitic transformation of the β phase occurs during quenching, and the more metastable β' phase is generated, thereby increasing the hardness of the product.

[0026] Furthermore, in step S3, the temperature of the aging treatment is 400°C-450°C, and the time is 8h-12h.

[0027] The beneficial effect of adopting the above further technical solution is that after aging heat treatment, fine (α+γ2) eutectoid structure is decomposed from the β' phase, thereby improving the strength and hardness of the product. As the tempering temperature rises, the precipitation of K phase increases and can be evenly distributed, reaching the maximum at 450℃, with the highest strength and hardness; when the temperature continues to rise, the α phase will gradually increase, and the grains will gradually coarsen, and the hardness will decrease accordingly.

[0028] Furthermore, in step S3, the profile is cooled using brine after the solution treatment.

[0029] The beneficial effect of adopting the above further technical solution is to ensure the overall uniformity of the alloy hardness.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] The present invention adopts a vacuum melting process to make an aluminum bronze alloy ingot with a specific composition ratio, thereby ensuring the stability of the composition and phase in the aluminum bronze alloy ingot, increasing the deformation amount and improving the mechanical properties by performing a hot forging process of roughening and expanding the aluminum bronze alloy ingot, and then performing a solid solution and aging heat treatment to further improve the mechanical properties; by designing a deformation and heat treatment process and adjusting the process steps and process parameters, it is ensured that the mechanical properties of the aluminum bronze guard ring are improved, and no cracks will occur in the entire preparation process, which is conducive to large-scale production;

[0032] Solution heat treatment is a process of heating the alloy to a point where all or the maximum amount of alloying elements such as aluminum, iron, and nickel are dissolved into the matrix to form a saturated or supersaturated solid solution, and then quenching to room temperature to obtain a supersaturated solid solution; aging heat treatment is a process of decomposing the supersaturated solid solution at room temperature or a higher temperature to precipitate a second phase (k phase), which can significantly increase the strength and hardness of the alloy; after solution treatment, a rapid cooling method of brine is used to ensure uniform hardness of the entire retaining ring;

[0033] The aluminum bronze retaining ring prepared by the present invention has a tensile strength of ≥800MPa, a yield strength of ≥550MPa, an elongation of ≥15%, and a hardness of ≥250HB;

[0034] The aluminum bronze guard ring prepared by the present invention has good surface quality, can meet the use requirements of the industry, has a simple process flow, can be subsequently processed after a slight cleaning, reduces the number of working steps, reduces costs, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a phase composition diagram of the edge portion of the aluminum bronze guard ring of Example 1 of the present invention;

[0036] Figure 2 This is a phase composition diagram of the core portion of the aluminum bronze guard ring of Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0038] Example 1

[0039] (1) Preparing an aluminum bronze alloy ingot: mixing raw materials according to the following weight percentages: 10.0 wt% Al, 7.0 wt% Fe, 8.0 wt% Ni, and the balance being copper, and smelting the Cu, Fe, Ni, and Al materials to obtain an aluminum bronze alloy ingot;

[0040] (2) The aluminum-bronze alloy ingot obtained in step (1) is upset into a round rod by a 4000t hydraulic press, and then expanded by a hole expanding machine. The deformation after upsetting and expanding is 80%, the heating temperature is 900°C, the holding time is 5h, and the final forging temperature is ≥650°C.

[0041] (3) After hot forging, the sample was subjected to thermal solution treatment at a temperature of 900°C for 4 h, and then rapidly cooled in brine; subsequently, an aging stabilization treatment was performed at a temperature of 430°C for 10 h.

[0042] Comparative Example 1

[0043] (1) Preparing an aluminum bronze alloy ingot: mixing raw materials according to the following weight percentages: 10.0 wt% Al, 7.0 wt% Fe, 8.0 wt% Ni, and the balance being copper, and smelting the Cu, Fe, Ni, and Al materials to obtain an aluminum bronze alloy ingot;

[0044] (2) The aluminum-bronze alloy ingot obtained in step (1) is upset into a round rod by a 4000t hydraulic press, and then expanded by a hole expanding machine. The deformation after upsetting and expanding is 40%, the heating temperature is 900°C, the holding time is 5h, and the final forging temperature is ≥650°C.

[0045] (3) After hot forging, the sample was subjected to thermal solution treatment at a temperature of 900°C for 4 h, and then rapidly cooled in brine; subsequently, an aging stabilization treatment was performed at a temperature of 430°C for 10 h.

[0046] Comparative Example 2

[0047] (1) Preparing an aluminum bronze alloy ingot: mixing raw materials according to the following weight percentages: 10.0 wt% Al, 7.0 wt% Fe, 8.0 wt% Ni, and the balance being copper, and smelting the Cu, Fe, Ni, and Al materials to obtain an aluminum bronze alloy ingot;

[0048] (2) The aluminum-bronze alloy ingot obtained in step (1) is upset into a round rod by a 4000t hydraulic press, and then expanded by a hole expanding machine. The deformation after upsetting and expanding is 80%, the heating temperature is 900°C, the holding time is 5h, and the final forging temperature is ≥650°C.

[0049] (3) After hot forging, the sample was subjected to thermal solution treatment at a temperature of 960°C for 4 h, followed by rapid cooling in brine; followed by aging stabilization treatment at a temperature of 430°C for 10 h.

[0050] Comparative Example 3

[0051] (1) Preparing an aluminum bronze alloy ingot: mixing raw materials according to the following weight percentages: 10.0 wt% Al, 7.0 wt% Fe, 8.0 wt% Ni, and the balance being copper, and smelting the Cu, Fe, Ni, and Al materials to obtain an aluminum bronze alloy ingot;

[0052] (2) The aluminum-bronze alloy ingot obtained in step (1) is uprooted into a round rod by a 4000t hydraulic press, and then expanded by a hole expanding machine. The deformation amount of uprooting and expanding is 80%, the heating temperature is 900°C, the holding time is 5h, and the final forging temperature is ≥650°C.

[0053] (3) After hot forging, the sample was subjected to thermal solution treatment at a temperature of 900°C for 4 h, followed by rapid cooling in brine; followed by aging stabilization treatment at a temperature of 500°C for 10 h.

[0054] Comparative Example 4

[0055] (1) Preparing an aluminum bronze alloy ingot: mixing raw materials according to the following weight percentages: 10.0 wt% Al, 7.0 wt% Fe, 8.0 wt% Ni, and the balance being copper, and smelting the Cu, Fe, Ni, and Al materials to obtain an aluminum bronze alloy ingot;

[0056] (2) The aluminum bronze alloy ingot obtained in step (1) is directly processed to obtain a guard ring.

[0057] The aluminum bronze guard ring obtained in the embodiment was subjected to mechanical property tests, and the test results are shown in Table 1.

[0058] Table 1 Mechanical properties test results of the aluminum bronze guard ring of the embodiment

[0059]

[0060] Note: The products of Example 1 and Comparative Examples 1-4 do not produce cracks. The present invention avoids the generation of cracks on the basis of ensuring the deformation amount and improving the strength and hardness of the product.

[0061] According to Table 1 and Figure 1-2 The results show that the aluminum bronze guard ring prepared by the present invention improves the tensile strength, yield strength and hardness value while ensuring that no cracks are generated and the elongation meets the requirements, and the preparation process is simple and reliable, which is conducive to large-scale production.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-magnetic aluminum bronze alloy, characterized in that: Calculated by weight percentage, the invention comprises the following components: Al 10.0-12.0wt%, Fe 6.0-8.0wt%, Ni 6.0-8.0wt%, and the balance is copper and inevitable impurities.

2. A non-magnetic aluminum bronze guard ring, characterized in that: The non-magnetic aluminum bronze alloy is prepared by using the non-magnetic aluminum bronze alloy described in claim 1.

3. A method for preparing the non-magnetic aluminum bronze retaining ring according to claim 2, characterized in that: The following steps are involved: S1, melting and casting the non-magnetic aluminum bronze alloy to obtain an aluminum bronze alloy ingot; S2, subjecting the aluminum-bronze alloy ingot to a hot forging treatment to obtain a profile; S3, subjecting the profile obtained in step S2 to solution treatment and aging treatment to obtain a non-magnetic aluminum bronze guard ring.

4. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S1, a vacuum melting process is adopted to place the non-magnetic aluminum-bronze alloy in a vacuum melting furnace to obtain an aluminum-bronze alloy ingot.

5. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S2, the hot forging treatment includes roughening and hole enlarging.

6. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S2, the temperature of the hot calcination treatment is 800-950°C, the holding time is 3-6h, the final calcination temperature is ≥650°C, and the total deformation of roughening and hole expansion is 60-80%.

7. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S3, the temperature of the solution treatment is 850°C-950°C, and the solution treatment time is 1-4h.

8. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S3, the aging treatment temperature is 400°C-450°C, and the time is 8h-12h.

9. The method for preparing the non-magnetic aluminum bronze guard ring according to claim 3, characterized in that: In step S3, the profile is cooled using brine after the solution treatment.

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