Heat treatment deformation control and performance improvement method for beryllium bronze disc spring

Abstract

The invention discloses a beryllium bronze disc spring heat treatment deformation control and performance improvement method which comprises the steps that a beryllium bronze TBe2 disc spring is clamped through a heat treatment anti-deformation tool, the heat treatment anti-deformation tool comprises an upper die, a lower die, a screw and a nut, and the beryllium bronze TBe2 disc spring is clamped between the upper die and the lower die and fixed through the screw and the nut; the heat treatment anti-deformation tool clamping the beryllium bronze TBe2 belleville spring is subjected to heat treatment, the temperature is increased to 220 + / -10 DEG C in 35-45 min, heat preservation is conducted for 1 / 2 t, the temperature is increased to 330 + / -10 DEG C in 15-25 min, heat preservation t is conducted, argon or high-purity nitrogen is filled for cooling, t = (1.5-2) * D * K, D is the effective thickness size of the tool, and K is the shape coefficient. Therefore, the disc spring is prevented from deforming in the heat treatment process, the heat treatment performance is improved, the quality of parts is improved, and the use requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of beryllium bronze, in particular to a method for controlling the heat treatment deformation and improving the performance of beryllium bronze disc springs. Background Art

[0002] Beryllium bronze TBe2 material is a non-ferrous bronze with high hardness, high strength limit, high elastic limit, good wear resistance, cold resistance, corrosion resistance, good thermal conductivity and good electrical conductivity. Because it also has excellent properties such as non-magnetic and non-sparking upon impact, it is widely used in precision instruments, the electronics industry and the aerospace industry.

[0003] After solution heat treatment, the structure of beryllium bronze is supersaturated α solid solution + a very small amount of uniformly distributed β phase, which has good plasticity and is convenient for machining and forming parts. Its properties are soft and ductile, and it is easy to carry out processing such as punching, pressing, bending, rolling, stretching and elongation. Therefore, after the beryllium bronze plates, strips, rods, wires and other profiles are solution-treated and accepted by the factory, they can generally be directly processed and formed, and then age heat treatment is carried out to obtain good hardness and elasticity.

[0004] However, for thin-walled beryllium bronze TBe2 disc springs, especially those with a wall thickness ≤ 2 mm, they are extremely prone to deformation during age heat treatment, making the height of the product unable to meet the requirements. Moreover, after using the conventional heat treatment system, the elasticity of the disc spring is insufficient and the elastic force is low, resulting in a very low qualified rate of the product. Summary of the Invention

[0005] The present invention provides a method for controlling the heat treatment deformation and improving the performance of beryllium bronze disc springs to prevent the disc springs from deforming during heat treatment, and to improve their heat treatment performance, thereby improving the quality of parts to meet the use requirements.

[0006] In a first aspect, there is provided a method for controlling the heat treatment deformation and improving the performance of beryllium bronze disc springs, including:

[0007] Using a heat treatment deformation prevention tooling to clamp the beryllium bronze TBe2 disc spring. The heat treatment deformation prevention tooling includes an upper die, a lower die, screws and nuts. The beryllium bronze TBe2 disc spring is clamped between the upper die and the lower die and fixed by the screws and nuts;

[0008] Performing heat treatment on the heat treatment deformation prevention tooling clamped with the beryllium bronze TBe2 disc spring. The system is: heating to 220 ± 10 °C in 35 - 45 min and holding for 1 / 2t, heating to 330 ± 10 °C in 15 - 25 min and holding for t, and cooling with argon or high-purity nitrogen, where t = (1.5 - 2) × D × K, D is the effective thickness dimension of the tooling, and K is the shape factor.

[0009] In combination with the first aspect, in some implementations of the first aspect, the lower die includes a first horizontal end face and a central column, and the upper die includes a second horizontal end face and a central hole; a beryllium bronze TBe2 disc spring is sleeved on the central column, the central column is inserted into the central hole, and the upper die and the lower die are locked and fixed by screws and nuts passing through the first horizontal end face and the second horizontal end face, so that the distance of the beryllium bronze TBe2 disc spring in the axial direction is limited.

[0010] In combination with the first aspect, in some implementations of the first aspect, the heat treatment anti-deformation tooling clamps multiple beryllium bronze TBe2 disc springs simultaneously, and the number does not exceed 20.

[0011] In combination with the first aspect, in some implementations of the first aspect, the heat treatment regime is: rising to 220°C in 40 min and holding for 1 / 2t, rising to 330°C in 20 min and holding for t.

[0012] In a second aspect, a heat treatment anti-deformation tooling is provided. The heat treatment anti-deformation tooling is applied to the heat treatment process of beryllium bronze TBe2 disc springs. The heat treatment anti-deformation tooling includes an upper die, a lower die, screws, and nuts. The lower die includes a first horizontal end face and a central column, and the upper die includes a second horizontal end face and a central hole; a beryllium bronze TBe2 disc spring is sleeved on the central column, the central column is inserted into the central hole, and the upper die and the lower die are locked and fixed by screws and nuts passing through the first horizontal end face and the second horizontal end face, so that the distance of the beryllium bronze TBe2 disc spring in the axial direction is limited.

[0013] In combination with the second aspect, in some implementations of the second aspect, the heat treatment anti-deformation tooling clamps multiple beryllium bronze TBe2 disc springs simultaneously, and the number does not exceed 20.

[0014] Compared with the prior art, the solution provided by the present invention at least includes the following beneficial technical effects:

[0015] The present invention designs a special anti-deformation heat treatment tooling. At the same time, through a large number of process tests, a special heat treatment process method for aging heat treatment of TBe2 disc springs with tooling is found. It not only controls the deformation of TBe2 disc springs during aging heat treatment, but also ensures the properties such as hardness and elasticity of the disc springs after heat treatment. Thus, the quality and performance of the parts are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a special anti-deformation heat treatment tooling.

[0017] Description of the reference numerals: 1 - lower die; 2 - upper die; 3 - screw; 4 - nut DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] As Figure 1 shown, the present invention provides a special heat treatment deformation prevention tooling, the material of which is 1Cr18Ni9Ti. The heat treatment deformation prevention tooling includes an upper die 2, a lower die 1, screws 3, and nuts 4. The beryllium bronze TBe2 disc spring is clamped between the upper die 2 and the lower die 1 and fixed by the screws 3 and nuts 4.

[0020] Among them, the lower die 1 includes a first horizontal end face and a central column, and the upper die 2 includes a second horizontal end face and a central hole. The beryllium bronze TBe2 disc spring is sleeved on the central column, the central column is inserted into the central hole, and the upper die 2 and the lower die 1 are locked and fixed by the screws 3 and nuts 4 passing through the first horizontal end face and the second horizontal end face, so that the distance of the beryllium bronze TBe2 disc spring in the axial direction is limited. In order to improve efficiency, the tooling can clamp multiple products for heat treatment at the same time, but the number should not exceed 20 pieces.

[0021] When the beryllium bronze TBe2 disc spring is heat-treated with the tooling, due to the thinness of the product, but the large size of the tooling, using the traditional heat treatment method, the holding time is insufficient, and the product performance is not ideal after directly heating to the aging temperature, unable to meet the use requirements.

[0022] In view of this, the present invention provides a process method for aging heat treatment of beryllium bronze TBe2 disc spring with tooling. After heat treatment, the hardness and elasticity of the product can be greatly improved, so as to meet the design and use requirements. The specific heat treatment system is: heating to 220°C in 40 min and holding for 1 / 2t, heating to 330°C in 20 min and holding for t, cooling with argon or high-purity nitrogen, where t = (1.5 - 2) × D × K, D is the effective thickness dimension of the tooling, and K is the shape factor. Measure the dimensions of the product before and after heat treatment with the tooling and compare them with the heat treatment of the product without the tooling to verify the effectiveness of the special tooling for heat treatment deformation prevention.

[0023] Example 1

[0024] The present invention designs 20 beryllium bronze TBe2 disc springs as test pieces. The product size requirements are: 5.7 ± 0.2, the Vickers hardness requirement is HV340 - 393, and the elastic force value requirement is > 5000N.

[0025] First, the dimensions of the product were measured before and after heat treatment without and with the anti-deformation tooling. Taking the height as an example, the results are shown in Table 1. The first 5 groups of test pieces with tooling in Table 1 adopted the traditional heat treatment aging system: holding temperature 320±10°C, holding time: 90 - 120 min, air cooling or gas-filled cooling; the last 5 groups of test pieces adopted the heat treatment aging system provided by the present invention: heating to 220°C in 40 min and holding for 140 min, heating to 330°C in 20 min and holding for 280 min, cooling with argon or high-purity nitrogen. (Note: heating to 220°C in 40 min and holding for 1 / 2t, heating to 330°C in 20 min and holding for t, cooling with argon or high-purity nitrogen, where t=(1.5 - 2)×D×K, D is the effective thickness dimension of the tooling, K is the shape factor. In this test, the effective thickness D of the tooling is 138 mm, and the shape factor K is 1.3 min / mm)

[0026] Table 1 Height (mm) of test pieces before and after heat treatment

[0027]

[0028] It can be seen from Table 1 that:

[0029] (1) Without the tooling, the height change of the product before and after heat treatment is large. After heat treatment, its height exceeds 5.7±0.2 mm, not meeting the dimensional requirements;

[0030] (2) With the tooling, the height of the product before and after heat treatment is small, and after heat treatment, its height still meets the dimensional requirements of 5.7±0.2 mm. This special tooling can effectively prevent the deformation of beryllium bronze TBe2 disc springs during the heat treatment process.

[0031] After heat treatment, the hardness and elastic force values were measured as shown in Table 2.

[0032] Table 2 Hardness and elastic force values after heat treatment

[0033]

[0034] It can be seen from Table 2 that:

[0035] (1) Adopting the traditional heat treatment system: holding temperature 320±10°C, holding time: 90 - 120 min, air cooling or gas-filled cooling, the hardness value after heat treatment is low, barely qualified, and the force value is low, far less than 5000 N;

[0036] (2) Adopting the innovative heat treatment method of the present invention, the hardness value of the product after heat treatment is significantly improved, and the elastic force value after heat treatment is greatly increased, both reaching above 5000 N, which can meet the product use requirements.

[0037] Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims of the present invention.

Claims

1. A method for controlling deformation and improving performance of beryllium bronze disc spring during heat treatment, characterized in that: include: The beryllium bronze TBe2 disc spring is clamped by a heat treatment anti-deformation tool. The heat treatment anti-deformation tool includes an upper die, a lower die, screws, and nuts. The beryllium bronze TBe2 disc spring is clamped between the upper die and the lower die and fixed by screws and nuts. The heat treatment anti-deformation fixture holding the beryllium bronze TBe2 disc spring is heat treated according to the following conditions: heating to 220±10℃ for 35-45min and keeping temperature for 1 / 2t, heating to 330±10℃ for 15-25min and keeping temperature for t, and cooling with argon or high-purity nitrogen, wherein t=(1.5-2)×D×K, D is the effective thickness of the fixture, and K is the shape coefficient.

2. The method according to claim 1, characterized in that The lower die includes a first horizontal end face and a center column, and the upper die includes a second horizontal end face and a center hole; the beryllium bronze TBe2 disc spring is sleeved on the center column, and the center column is inserted into the center hole. The upper die and the lower die are locked and fixed by screws and nuts passing through the first horizontal end face and the second horizontal end face, so that the axial distance of the beryllium bronze TBe2 disc spring is limited.

3. The method according to claim 1, characterized in that The heat treatment anti-deformation fixture clamps multiple beryllium bronze TBe2 disc springs at the same time, and the number does not exceed 20.

4. The method according to claim 1, characterized in that Heat treatment system: 40min to 220℃ and keep warm for 1 / 2t, 20min to 330℃ and keep warm for t.

5. A heat treatment anti-deformation tool, characterized in that: The heat treatment anti-deformation tooling is applied to the heat treatment process of beryllium bronze TBe2 disc springs. The heat treatment anti-deformation tooling includes an upper die, a lower die, screws, and nuts. The lower die includes a first horizontal end face and a center column, and the upper die includes a second horizontal end face and a center hole. The beryllium bronze TBe2 disc spring is sleeved on the center column, and the center column is inserted into the center hole. The upper die and the lower die are locked and fixed by screws and nuts passing through the first horizontal end face and the second horizontal end face, so that the axial distance of the beryllium bronze TBe2 disc spring is limited.

6. The heat treatment anti-deformation tooling according to claim 5, characterized in that: The heat treatment anti-deformation fixture clamps multiple beryllium bronze TBe2 disc springs at the same time, and the number does not exceed 20.

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