Beryllium bronze alloy bar for aerospace and preparation method

Abstract

The invention discloses a beryllium bronze alloy bar for aerospace and a preparation method, and belongs to the field of copper-based alloys. The preparation method comprises the steps that a beryllium bronze alloy cast ingot is heated to 500-800 DEG C and then subjected to heat preservation for 1-10 h, the heated cast ingot is forged for the first time, the final forging temperature is larger than or equal to 500 DEG C, and a first bar billet is obtained; the first bar blank is heated to 500-800 DEG C and then subjected to heat preservation for 1-12 h, the heated first bar blank is subjected to extrusion forming, and a second bar blank is obtained; the second bar blank is heated to 500-800 DEG C and then subjected to heat preservation for 1-10 h, the heated second bar blank is forged for the second time, the final forging temperature is larger than or equal to 500 DEG C, and a third bar blank is obtained; the third bar blank is heated to 500-800 DEG C and then subjected to heat preservation for 1-10 h, the heated third bar blank is subjected to hot rolling, the finish rolling temperature is larger than or equal to 500 DEG C, and a fourth bar blank is obtained; and the fourth bar blank is machined after being subjected to heat treatment, and the beryllium bronze alloy bar is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper-based alloys, and particularly relates to a beryllium bronze alloy rod for aerospace and a preparation method thereof. BACKGROUND

[0002] The beryllium bronze alloy rod is widely used in the fields of aviation, aerospace, electronics, electrical appliances, communication, etc. Through the combination of multiple processes such as extrusion, forging and hot rolling, the beryllium bronze alloy rod with fine and uniform grains, high performance of mechanical properties and hardness, and pure and dense internal structure and few defects can be prepared, which can stably play the advantages of high strength, high elasticity, good wear resistance and fatigue resistance, etc. in more severe experimental conditions or use environments. The beryllium bronze alloy rod is applied to high-precision electronic equipment, aerospace components, high-performance wires and connectors, etc.

[0003] However, the existing preparation process of the beryllium bronze alloy has the following problems:

[0004] (1) Single process: relying on single rolling or hot working, the grain refinement is insufficient, and the uniformity of the structure is poor.

[0005] (2) Performance limitation: low consistency of mechanical properties, and weak control ability of internal defects (such as pores and inclusions).

[0006] (3) Insufficient adaptability: unable to meet the differentiated needs of different scenes through process adjustment. SUMMARY

[0007] To solve the above technical problems, the application provides a beryllium bronze alloy rod for aerospace and a preparation method thereof. Through the synergistic effect of forging, extrusion and hot rolling, the grain refinement and homogenization, segregation and pore-free of the beryllium bronze alloy rod are realized, and the diversified needs of aviation and aerospace are met.

[0008] The first aspect of the application provides a preparation method of a beryllium bronze alloy rod for aerospace, which comprises the following steps:

[0009] Step S1, obtaining a beryllium bronze alloy ingot, heating the ingot to 500-800 DEG C and keeping for 1-10 h, and performing first forging on the heated ingot for 1-20 times, with a final forging temperature of greater than or equal to 500 DEG C, to obtain a first rod blank;

[0010] Step S2, heating the first rod blank to 500-800 DEG C and keeping for 1-12 h, and performing extrusion forming on the heated first rod blank to obtain a second rod blank;

[0011] Step S3, heating the second rod blank to 500-800 DEG C and keeping for 1-10 h, and performing second forging on the heated second rod blank for 1-20 times, with a final forging temperature of greater than or equal to 500 DEG C, to obtain a third rod blank.

[0012] Step S4, after the third billet is heated to 500-800℃ and kept for 1-10h, the third billet after heating is hot-rolled for 1-20 passes, the deformation of each pass is ≤20%, the final rolling temperature is ≥500℃, and a fourth billet is obtained;

[0013] Step S5, the fourth billet is machined after heat treatment, and a beryllium bronze alloy rod is obtained.

[0014] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, the heat treatment of the fourth billet in step S5 includes: the fourth billet is sequentially subjected to solid solution, water cooling and aging.

[0015] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, the temperature of the solid solution is 500-900℃, and the time is 1-10h.

[0016] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, the temperature of the aging is 300-400℃, and the time is 1-10h.

[0017] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, in step S1, the composition and mass percentage of the beryllium bronze ingot are as follows:

[0018] Be: 1.6-2.2%, Ni: 0.1-0.7%, the balance being Cu and inevitable impurities.

[0019] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, the inevitable impurities include: Fe, Al, Si and Pb.

[0020] According to the preparation method of the beryllium bronze alloy rod according to the first aspect of the present application, the mass percentage of Fe, Al, Si and Pb is not more than 0.4%.

[0021] The second aspect of the present application proposes an aerospace beryllium bronze alloy rod, which is prepared by the preparation method described above.

[0022] The scheme proposed by the present application has the following technical effects:

[0023] The present application improves the organization of the raw material through the synergistic effect of forging, extrusion and hot rolling, fully breaks the casting organization, eliminates defects such as pores, shrinkage and dendritic crystals formed during the smelting process, ensures the continuity of the fiber organization, forms a dense organization, improves the comprehensive performance of the rod, refines the grain, and meets the diversified needs of aerospace.

[0024] In addition, the average grain size of the beryllium bronze alloy rod obtained by the method is ≤100 μm, and the maximum grain size is ≤200 μm.

[0025] In addition, the ultrasonic detection reflection wave of the beryllium bronze alloy rod obtained by the method is ≤60%. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] The first aspect of the embodiment provides a preparation method of a beryllium bronze alloy rod for aerospace. Multi-directional plastic deformation is realized by forging (upsetting and elongating) and rolling to promote dynamic recrystallization of grains, so that the average grain size is ≤100 μm. At the same time, multi-stage heating and deformation are used to eliminate casting defects such as pores and composition segregation, so that the ultrasonic detection reflection wave is ≤60%.

[0028] The preparation method comprises:

[0029] In step S1, a beryllium bronze alloy ingot is obtained, and the ingot is heated to 500-800 ℃ and kept for 1-10 h. The heated ingot is subjected to first forging for 1-20 times, and the final forging temperature is ≥500 ℃, to obtain a first rod blank.

[0030] The first forging in the embodiment breaks the casting dendrites and preliminarily refines the grains, providing a uniform blank for subsequent extrusion. The forging at 500-800 ℃ can avoid β→α phase change cracks, and the multi-time reheating forging can realize recrystallization annealing and eliminate work hardening.

[0031] Preferably, in the step S1, the heating temperature is 600-700 ℃, and the time is 5-8 h.

[0032] Preferably, in the step S1, the number of upsetting and elongating in the first forging is 3-10 times.

[0033] In some embodiments, in the step S1, the composition and mass percentage of the beryllium bronze alloy ingot are as follows:

[0034] Be: 1.6-2.2%, Ni: 0.1-0.7%, the balance being Cu and inevitable impurities.

[0035] The Be content is optimized to balance the strength and plasticity of the beryllium bronze alloy, and the addition of Ni enhances the solid solution and aging hardening effect of the alloy, and low impurities ensure the electrical conductivity and corrosion resistance of the alloy.

[0036] In some embodiments, the inevitable impurities include Fe, Al, Si, and Pb.

[0037] In some embodiments, the mass percentage of each of Fe, Al, Si, and Pb is not greater than 0.4%.

[0038] In step S2, the first bar blank is heated to 500-800°C and held for 1-12h, and then the heated first bar blank is extruded to obtain a second bar blank.

[0039] The extrusion forming in this embodiment eliminates pores by using three-way compressive stress and forms fibrous structure to improve the density of the alloy. Extrusion forming at 500-800°C can prevent overburning.

[0040] Preferably, in the step S2, the heating temperature is 600-700°C, and the time is 5-8h.

[0041] In step S3, the second bar blank is heated to 500-800°C and held for 1-10h, and then the heated second bar blank is forged for 1-20 times, and the final forging temperature is ≥500°C, to obtain a third bar blank.

[0042] The second forging in this embodiment further breaks up coarse grains and promotes dynamic recrystallization to improve the uniformity of the structure. Forging at 500-800°C can avoid cracks, and multiple re-heating forging can achieve secondary recrystallization to refine grains and eliminate work hardening.

[0043] Preferably, in the step S3, the heating temperature is 600-700°C, and the time is 5-8h.

[0044] Preferably, in the step S3, the upsetting and elongation in the first forging is performed for 3-10 times.

[0045] In step S4, the third bar blank is heated to 500-800°C and held for 1-10h, and then the heated third bar blank is hot rolled for 1-20 passes, and the deformation amount of each pass is ≤20%, and the final rolling temperature is ≥500°C, to obtain a fourth bar blank.

[0046] The hot rolling in this embodiment eliminates anisotropy by multi-directional rolling, and the pass design controls dimensional accuracy and refines grains to a sub-micron level. Hot rolling at 500-800°C can retain the recrystallization driving force, and controlling the deformation amount of each pass to ≤20% can avoid cracks.

[0047] Preferably, in the step S4, the heating temperature is 600-700℃, and the time is 5-8h.

[0048] Preferably, in the step S4, the deformation per pass is ≤15%.

[0049] Step S5, after the heat treatment of the fourth billet, machining is performed to obtain a beryllium bronze alloy rod.

[0050] In some embodiments, in the step S5, the heat treatment of the fourth billet comprises: sequentially performing solid solution, water cooling and aging on the fourth billet.

[0051] In some embodiments, the temperature of the solid solution is 500-900℃, and the time is 1-10h.

[0052] Preferably, the temperature of the solid solution is 600-800℃, and the time is 5-8h.

[0053] In some embodiments, the temperature of the aging is 300-400℃, and the time is 1-10h.

[0054] Preferably, the temperature of the aging is 330-370℃, and the time is 5-8h.

[0055] The effect of the solid solution in this embodiment is to homogenize the components, the effect of the water cooling after the solid solution is to freeze the high-temperature structure, and finally the strengthening phase is precipitated through aging to improve the hardness and strength of the alloy.

[0056] In some embodiments, in the step S5, a lathe, a centerless lathe or other machining equipment is used for machining to obtain a finished rod of a required specification.

[0057] When the centerless lathe is used for finishing, the surface roughness Ra is ≤0.8μm, and the dimensional tolerance is ±0.5mm.

[0058] The second aspect of this embodiment proposes an aerospace beryllium bronze alloy rod, which is prepared by the preparation method described above.

[0059] Embodiment 1

[0060] Step S1, obtain a beryllium bronze alloy ingot, heat the ingot to 650℃ and keep for 6h, perform the first forging on the heated ingot for 10 times, and the final forging temperature is ≥550℃, to obtain a first billet. The composition and mass percentage of the beryllium bronze alloy ingot are as follows: Be: 1.8%, Ni: 0.4%, the balance being Cu and unavoidable impurities; the unavoidable impurities include: Fe, Al, Si and Pb, each with a mass percentage of not more than 0.4%.

[0061] Step S2, the first rod blank is heated to 650℃ and kept for 7h, and the first rod blank after heating is subjected to extrusion forming to obtain a second rod blank.

[0062] Step S3, the second rod blank is heated to 650℃ and kept for 6h, and the second rod blank after heating is subjected to 10 times of second forging, and the final forging temperature is greater than or equal to 550℃ to obtain a third rod blank.

[0063] Step S4, the third rod blank is heated to 650℃ and kept for 6h, and the third rod blank after heating is subjected to 10 passes of hot rolling, and the deformation amount of each pass is less than or equal to 15%, and the final rolling temperature is greater than or equal to 550℃ to obtain a fourth rod blank.

[0064] Step S5, the fourth rod blank is sequentially subjected to solid solution, water cooling, aging and machining to obtain a beryllium bronze alloy rod. The solid solution temperature is 700℃, and the time is 5h; the aging temperature is 350℃, and the time is 5h.

[0065] Example 2

[0066] Step S1, a beryllium bronze alloy ingot is obtained, the ingot is heated to 500℃ and kept for 10h, and the ingot after heating is subjected to 5 times of first forging, and the final forging temperature is greater than or equal to 500℃ to obtain a first rod blank. The composition and mass percentage of the beryllium bronze alloy ingot are as follows: Be: 1.6%, Ni: 0.1%, and the balance is Cu and unavoidable impurities; the unavoidable impurities include Fe, Al, Si and Pb, each with a mass percentage of not more than 0.4%.

[0067] Step S2, the first rod blank is heated to 500℃ and kept for 12h, and the first rod blank after heating is subjected to extrusion forming to obtain a second rod blank.

[0068] Step S3, the second rod blank is heated to 500℃ and kept for 10h, and the second rod blank after heating is subjected to 5 times of second forging, and the final forging temperature is greater than or equal to 500℃ to obtain a third rod blank.

[0069] Step S4, the third rod blank is heated to 500℃ and kept for 10h, and the third rod blank after heating is subjected to 5 passes of hot rolling, and the deformation amount of each pass is less than or equal to 20%, and the final rolling temperature is greater than or equal to 500℃ to obtain a fourth rod blank.

[0070] Step S5, the fourth rod blank is sequentially subjected to solid solution, water cooling, aging and machining to obtain a beryllium bronze alloy rod. The solid solution temperature is 500℃, and the time is 10h; the aging temperature is 300℃, and the time is 10h.

[0071] Example 3

[0072] Step S1, obtain a beryllium bronze alloy ingot, heat the ingot to 800 DEG C and keep for 2 hours, perform first forging on the heated ingot for 20 times, and the final forging temperature is greater than or equal to 600 DEG C, to obtain a first bar blank. The composition and mass percentage of the beryllium bronze alloy ingot are as follows: Be: 2.2%, Ni: 0.7%, the balance being Cu and inevitable impurities; the inevitable impurities include Fe, Al, Si and Pb, each of which has a mass percentage of less than or equal to 0.4%.

[0073] Step S2, heat the first bar blank to 800 DEG C and keep for 3 hours, and perform extrusion forming on the heated first bar blank, to obtain a second bar blank.

[0074] Step S3, heat the second bar blank to 800 DEG C and keep for 2 hours, and perform second forging on the heated second bar blank for 20 times, and the final forging temperature is greater than or equal to 600 DEG C, to obtain a third bar blank.

[0075] Step S4, heat the third bar blank to 800 DEG C and keep for 2 hours, and perform hot rolling on the heated third bar blank for 20 passes, and the deformation of each pass is less than or equal to 20%, and the final rolling temperature is greater than or equal to 600 DEG C, to obtain a fourth bar blank.

[0076] Step S5, sequentially perform solid solution, water cooling, aging and machining on the fourth bar blank, to obtain a beryllium bronze alloy bar. The solid solution temperature is 900 DEG C, and the time is 2 hours; the aging temperature is 400 DEG C, and the time is 2 hours.

[0077] It is tested that the beryllium bronze alloy bars obtained in Examples 1-3 have no scratches and cracks on the surface, the ultrasonic detection reflection wave is less than or equal to 60%, the average grain size is less than or equal to 100 mu m, and the maximum grain size is less than or equal to 200 mu m.

[0078] In summary, the scheme provided in the present application has the following technical effects:

[0079] The present application improves the raw material organization through the synergistic effect of forging, extrusion and hot rolling, fully breaks the casting organization, eliminates defects such as pores, shrinkage holes and dendritic crystals formed in the smelting process, ensures the continuity of the fiber organization, forms a dense organization, improves the comprehensive performance of the bar, refines the grain, and meets the diversified needs of aerospace.

[0080] In addition, the average grain size of the beryllium bronze alloy bar obtained by the present application is less than or equal to 100 mu m, and the maximum grain size is less than or equal to 200 mu m.

[0081] In addition, the ultrasonic detection reflection wave of the beryllium bronze alloy bar obtained by the present application is less than or equal to 60%.

[0082] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing beryllium bronze alloy rods for aerospace, characterized in that: The preparation method comprises: Step S1, obtaining a beryllium bronze alloy ingot, heating the ingot to 500-800° C. and then keeping the temperature for 1-10 hours, performing a first forging on the heated ingot for 1-20 times, with a final forging temperature of ≥500° C., to obtain a first billet; Step S2, heating the first rod blank to 500-800° C. and keeping the temperature for 1-12 hours, and extruding the heated first rod blank to obtain a second rod blank; Step S3, heating the second rod blank to 500-800° C. and keeping the temperature for 1-10 hours, performing a second forging on the heated second rod blank for 1-20 times, with the final forging temperature being ≥500° C., to obtain a third rod blank; Step S4, heating the third bar blank to 500-800° C. and then keeping the temperature for 1-10 hours, hot rolling the heated third bar blank for 1-20 passes, with a deformation of each pass ≤ 20% and a final rolling temperature ≥ 500° C., to obtain a fourth bar blank; Step S5: heat-treating and then machining the fourth rod blank to obtain a beryllium bronze alloy rod.

2. The method for preparing beryllium bronze alloy rod according to claim 1, characterized in that: In the step S5, heat treating the fourth rod blank includes: performing solid solution treatment, water cooling and aging on the fourth rod blank in sequence.

3. The method for preparing beryllium bronze alloy rod according to claim 2, characterized in that: The temperature of the solid solution is 500-900° C., and the time is 1-10 hours.

4. The method for preparing beryllium bronze alloy rod according to claim 2, characterized in that: The aging temperature is 300-400° C., and the aging time is 1-10 hours.

5. The method for preparing beryllium bronze alloy rod according to claim 1, characterized in that: In step S1, the composition and mass percentage of the beryllium bronze alloy ingot are as follows: Be: 1.6-2.2%, Ni: 0.1-0.7%, and the balance is Cu and inevitable impurities.

6. The method for preparing beryllium bronze alloy rod according to claim 5, characterized in that: The unavoidable impurities include Fe, Al, Si and Pb.

7. The method for preparing beryllium bronze alloy rod according to claim 6, characterized in that: The mass percentages of Fe, Al, Si and Pb are all no greater than 0.4%.

8. A beryllium bronze alloy bar for aerospace, characterized in that: The beryllium bronze alloy rod is prepared by the preparation method according to any one of claims 1 to 7.