Diffusion welding of beryllium copper and tool steel

Abstract

The application belongs to the technical field of connection of metal materials, and discloses a diffusion welding method of beryllium copper and tool steel. ‑3 The application discloses a diffusion welding method of beryllium copper and tool steel, which comprises the following steps: (1) polishing and polishing the welding surface of the beryllium copper and the tool steel, and then cleaning; (2) assembling the beryllium copper and the tool steel in a package; (3) sending the assembled package into a vacuum degassing furnace, setting the temperature to 300-350 DEG C, and performing vacuumization on the package in the process, until the vacuum degree reaches 1*10 ‑3 Pa; (4) assembling the degassed package into a hot isostatic pressing device, and then performing hot isostatic pressing, using a protective gas as a pressure medium, setting the hot pressing temperature to 600-650 DEG C, setting the pressure to 100-130 Mpa, and setting the holding and pressure maintaining time to 2-4 h; (5) after the hot isostatic pressing is completed, furnace cooling is performed, then the package is cut open, and the beryllium copper-tool steel diffusion welding finished product is obtained. The beryllium copper-tool steel diffusion welding finished product prepared by the application has a high welding surface bonding rate and good tensile strength.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of connection of metal materials, and relates to a diffusion welding method for beryllium copper and tool steel. BACKGROUND

[0002] Beryllium is a rare metal, and has the advantages of low density, high specific strength and specific heat capacity, and good thermal conductivity. Beryllium copper alloy, which is a non-ferrous alloy elastic material with excellent comprehensive performance, has a chemical formula of BeCu, and is mainly used for manufacturing connectors, shell fragments, switches and other electronic and electrical device components, and is used in the fields of aerospace vehicles, automobiles, computers, national defense and mobile communication.

[0003] The connection of beryllium copper and tool steel is one of the difficulties of nuclear industrial engineering materials. Since beryllium has poor ductility, great brittleness and poor compatibility with stainless steel, it is easy to react with many other metals to form brittle intermetallic compounds at high temperatures, and pores and cracks are easy to be generated in welding, which leads to great difficulty in connecting beryllium copper and tool steel.

[0004] Patent CN114473163A proposes a welding method for beryllium copper. First, the welding surface is cleaned and placed horizontally on a resistance welding device, and a layer of high-temperature-resistant coating is applied to the beryllium copper welding surface. Then, the electrode of the resistance welding device is used to contact the welding part, a temperature of 1500 DEG C to 2000 DEG C is applied, so that both welding parts reach the melting point temperature, the two welding parts are moved to contact and complete welding. Finally, in order to ensure the original performance of beryllium copper, after the welding part is cooled, heat treatment needs to be performed again, and stamping treatment is performed after heat treatment. This method needs resistance welding, heat treatment and stamping treatment, and the steps are complicated, batch production is difficult, and the success rate of welding cannot be completely guaranteed. Secondly, the resistance welding temperature is high, which is easy to cause damage to the welding base material. Even if heat treatment is performed again, it is difficult to ensure that the welded part restores to the performance before welding.

[0005] Patent CN106271013A invented a copper and copper alloy and steel low vacuum diffusion welding method, the copper / copper alloy and steel to be welded surface polishing, cleaning after butt joint assembly, laying film remover or containing film remover between the butt joint surface, assembly to get the connecting piece, the film remover is B, Li, B2O3, KF, LiF, AlF3, CaF2, etc. Or at least one of the borate; The connecting piece is placed between the upper and lower pressure heads of the diffusion welding furnace, and a pre-pressure of 1.0~1.5Mpa is applied, the diffusion welding furnace is vacuumized to the vacuum degree in the furnace is not higher than 800Pa, then heating starts, when the temperature in the furnace reaches 600~850℃, the axial back pressure of 4~10Mpa is applied to the connecting piece, and the pressure is kept for 6~30min; After the diffusion welding of the connecting piece is completed, the pressure is removed, and the furnace is cooled. This invention can realize the diffusion connection of copper / copper alloy and steel under the condition of low vacuum and low welding temperature, and there is no element volatilization in the welding process. However, it is necessary to add film remover, and the welded sample is placed between the upper and lower pressure heads of the diffusion welding furnace, only one product can be welded at a time, the production efficiency is low, and the low vacuum of 800Pa cannot meet the diffusion welding requirements of all copper alloys, such as beryllium copper, which is prone to generate pores and intermetallic compounds during welding. SUMMARY

[0006] In view of the above problems existing in the prior art, the purpose of the present application is to provide a diffusion welding method for beryllium copper and tool steel.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0008] A diffusion welding method for beryllium copper and tool steel, comprising the following steps:

[0009] (1) polishing and polishing the beryllium copper and tool steel welding surface flat, and then washing;

[0010] (2) assemble the beryllium copper and tool steel into a package;

[0011] (3) send the assembled package into a vacuum degassing furnace, and set the temperature to 300~350℃, and vacuumize the package during the process;

[0012] (4) assemble the degassed package into a hot isostatic pressing device, and then perform hot isostatic pressing, using protective gas as pressure medium, hot pressing temperature is 600~650℃, pressure is 100~130Mpa, and holding time is 2~4h;

[0013] (5) after hot isostatic pressing, cool down with the furnace, then take out the furnace, cut open the package, and get the beryllium copper-tool steel diffusion welded product.

[0014] Preferably, in step (1), the beryllium copper and tool steel welding surface is polished and polished flat by mechanical polishing.

[0015] Preferably, the cleaning method of step (1) is: first pickling, and then cleaning the welding surface with an organic solvent; further preferably, the acid solution for pickling is dilute hydrochloric acid or dilute sulfuric acid with a mass concentration of 8-18%, and the organic solvent is acetone or alcohol, and the cleaning method of the organic solvent is ultrasonic cleaning.

[0016] Preferably, in step (3), the heating rate is 5-10℃ / min.

[0017] Preferably, in step (3), the holding time is 3-5h.

[0018] Preferably, in step (3), the vacuum degree is 2×10 -3 ~1×10 -4 pa.

[0019] Preferably, in step (4), the protective gas is inert gas or nitrogen.

[0020] Preferably, in step (4), the heating rate is 2-5℃ / min.

[0021] Preferably, in step (2), the package cover comprises a bottom plate, an outer side plate, a support plate, graphite paper, a cover plate and a degassing pipe, the bottom plate is installed at the bottom of the outer side plate, the cover plate is installed at the top of the outer side plate, a through hole is arranged on the cover plate, the degassing pipe is installed at the through hole, and the support plate and the graphite paper are arranged in the accommodating space formed by the bottom plate, the outer side plate and the cover plate.

[0022] Further preferably, the assembly process is as follows: the bottom plate and the outer side plate are assembled to form a package cover semi-finished product with an open end, graphite paper is padded on the side wall and the bottom of the package cover semi-finished product, and then the support plate, the graphite paper, the beryllium copper and the tool steel are sequentially placed as a circulating unit, wherein the order of the beryllium copper and the tool steel in the circulating unit can be adjusted, and the last circulating unit is placed, then the support plate and the graphite paper are sequentially placed, finally the cover plate is used to seal and fix the opening of the package cover semi-finished product, and the degassing pipe is installed at the through hole of the cover plate, and the assembly is completed.

[0023] Further preferably, the topmost graphite paper is flush with the opening of the package cover semi-finished product.

[0024] Further preferably, the installation methods of the bottom plate and the outer side plate, the top plate and the outer side plate, and the top plate and the degassing pipe are all welding fixation.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] (1) The vacuum degassing and hot isostatic pressing diffusion welding process adopted by the present application can ensure that the product preparation process is in an infinitely close-to-vacuum state, so that a large pressure difference is formed inside and outside the sleeve, and the beryllium copper and tool steel inside the sleeve are uniformly subjected to a large pressure, so that the two are tightly combined. The hot isostatic pressing process uses inert gas medium to pressurize, so that the welding part is uniformly stressed and is not prone to deformation, and the diffusion welding temperature can also be reduced. The beryllium copper-tool steel diffusion welded product finally prepared has a high bonding rate of the welding surface and good tensile strength.

[0027] (2) The hot isostatic pressing process adopted by the present application has a large space, can batch weld, and the welded sample does not need to be processed and can be directly used, so the efficiency is high and the cost is low.

[0028] (3) The present application adopts a sleeve heating vacuum degassing process, which can effectively remove water vapor, oxygen and other substances in the sleeve, so that an ultra-low pressure vacuum is formed inside the sleeve, and intermetallic oxides, hydrides and other harmful substances are avoided on the welding surface.

[0029] (4) The diffusion welding temperature of the present application is 600-650℃, which can effectively avoid the softening of the welding base material due to heating, thereby avoiding problems such as deformation, grain growth and recrystallization of the welded sample. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and are used together with embodiments of the present application to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0031] Figure 1 is a schematic diagram of the assembly structure of the present application;

[0032] Among them: 1-cover plate, 2-tool steel, 3-beryllium copper, 4-support plate, 5-graphite paper, 6-gas removal pipe, 7-outer plate, 8-bottom plate. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the drawings and preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0034] Unless otherwise defined, all professional terms used herein have the same meaning as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0035] Example 1

[0036] The present embodiment discloses a diffusion welding method of beryllium copper and tool steel, comprising the following steps:

[0037] (1) Welding surface treatment, the beryllium copper and tool steel welding surface is polished flat by mechanical polishing, and then the welding surface is washed clean by 15% dilute hydrochloric acid, so that the welding surface has good diffusion welding conditions;

[0038] (2) Referring to Figure 1 , a package is prepared, the package including a bottom plate 8, an outer side plate 7, a support plate 4, graphite paper 5, a cover plate 1 and a degassing pipe 6, the bottom plate 8 is installed at the bottom of the outer side plate 7, the cover plate 1 is installed at the top of the outer side plate 7, a through hole is arranged on the cover plate 1, the degassing pipe 6 is installed at the through hole, and the support plate 1 and the graphite paper 5 are arranged in the accommodating space formed by the bottom plate 8, the outer side plate 7 and the cover plate 1. The assembly process is as follows: the bottom plate 8 and the outer side plate 7 are assembled to form a package semi-finished product with an open end, the graphite paper 5 is arranged on the side wall and the bottom of the package semi-finished product, then the support plate 4, the graphite paper 5, the beryllium copper 3 and the tool steel 2 are sequentially arranged, then the support plate 4, the graphite paper 5 and the graphite paper 5 at the top are sequentially placed, the graphite paper 5 at the top is flush with the opening of the package semi-finished product, finally the opening of the package semi-finished product is sealed and fixed by using the cover plate 1, and the degassing pipe 6 is installed at the through hole of the cover plate 1, the assembly is completed, and the installation modes of the bottom plate 8 and the outer side plate 7, the cover plate 1 and the outer side plate 7 and the cover plate 1 and the degassing pipe 6 are all welding fixation;

[0039] (3) The assembled package is sent into a vacuum degassing furnace, the temperature is raised to 300℃ at a rate of 5℃ / min, and the temperature is kept for 5h, in the process, the package is vacuumized, until the vacuum degree reaches 1.0×10 -3 Pa;

[0040] (4) The package after degassing is loaded into a hot isostatic pressing device, and then hot isostatic pressing is performed, argon is used as a pressure medium, the hot pressing temperature is 600℃, the pressure is 100Mpa, the temperature and pressure keeping time is 4h, and the temperature rising rate is 5℃ / min;

[0041] (5) After furnace cooling, the package is taken out of the furnace, the package is cut open after being taken out of the furnace, the welding sample is taken out, the surface is treated clean, and a beryllium copper-tool steel diffusion welded product is obtained.

[0042] The tensile strength of the welding sample is measured by using a universal electronic tensile testing machine, and the welding surface bonding rate is measured by using an ultrasonic flaw detector, and the detection data are shown in Table 1.

[0043] Example 2

[0044] The embodiment discloses a diffusion welding method of beryllium copper and tool steel, including the following steps:

[0045] (1) Welding surface treatment, the beryllium copper and tool steel welding surface is polished flat by mechanical polishing, and then the welding surface is washed clean by 15% dilute hydrochloric acid, so that the welding surface has good diffusion welding conditions;

[0046] (2) Referring toFigure 1 , prepare a package, the package includes the bottom plate 8, the outer side plate 7, the support plate 4, the graphite paper 5, the cover plate 1 and the degassing pipe 6, the bottom plate 8 is installed at the bottom of the outer side plate 7, the cover plate 1 is installed at the top of the outer side plate 7, the cover plate 1 is provided with a through hole, the degassing pipe 6 is installed at the through hole, the support plate 1 and the graphite paper 5 are padded in the containing space formed by the bottom plate 8, the outer side plate 7 and the cover plate 1. The assembly process is as follows: assemble the bottom plate 8 and the outer side plate 7 to form a package semi-finished product with one end opening, pad the graphite paper 5 on the side wall and the bottom of the package semi-finished product, then pad the support plate 4, the graphite paper 5, the beryllium copper 3 and the tool steel 2 in sequence, then place the support plate 4, the graphite paper 5 and the graphite paper 5 at the top in sequence, the topmost graphite paper 5 is flush with the opening of the package semi-finished product, finally seal and fix the opening of the package semi-finished product by using the cover plate 1, and install the degassing pipe 6 at the through hole of the cover plate 1, complete the assembly, and the installation modes of the bottom plate 8 and the outer side plate 7, the cover plate 1 and the outer side plate 7 and the cover plate 1 and the degassing pipe 6 are all welding fixation;

[0047] (3) the assembled package is sent into a vacuum degassing furnace, the temperature is increased to 330 DEG C, the temperature increasing rate is 8 DEG C / min, and the temperature is kept for 4h, in the process, the package is vacuumized, until the vacuum degree reaches 1.0*10 -3 Pa;

[0048] (4) the package after degassing is assembled into a HiP device, then hot isostatic pressing is carried out, argon is used as pressure medium, the hot pressing temperature is 620 DEG C, the pressure is 115Mpa, and the temperature keeping and pressure keeping time is 3h, and the temperature increasing rate is 3 DEG C / min;

[0049] (5) after furnace cooling, the package is taken out, the package is cut open after being taken out, the welded sample is taken out, the surface is treated clean, and the beryllium copper-tool steel diffusion welded product is obtained.

[0050] The tensile strength of the welded sample is measured by using a universal electronic tensile testing machine, and the bonding rate of the welded surface is measured by using an ultrasonic flaw detector, and the detection data are shown in Table 1.

[0051] Example 3

[0052] The embodiment discloses a diffusion welding method of beryllium copper and tool steel, which comprises the following steps:

[0053] (1) the welding surface is treated, the beryllium copper and tool steel welding surface is polished flat by mechanical polishing, then the welding surface is washed clean by using 15% dilute hydrochloric acid, so that the welding surface has good diffusion welding conditions;

[0054] (2) refer to Figure 1, the preparation package cover, the package cover includes the bottom plate 8, the outer side plate 7, the support plate 4, graphite paper 5, the cover plate 1 and the degassing pipe 6, the bottom plate 8 is installed at the bottom of the outer side plate 7, the cover plate 1 is installed at the top of the outer side plate 7, the cover plate 1 is provided with through hole, the through hole is installed degassing pipe 6, support plate 1, graphite paper 5 pad is in the containing space formed by the bottom plate 8, the outer side plate 7, the cover plate 1. Assembly process is specifically as follows: the bottom plate 8 and the outer side plate 7 are assembled, the package cover semi-finished product with one end opening is formed, the graphite paper 5 is padded in the side wall and the bottom of the package cover semi-finished product, then the support plate 4, the graphite paper 5, the beryllium copper 3, the tool steel 2 are sequentially padded, then the support plate 4, the graphite paper 5 are sequentially placed, the topmost graphite paper 5 is flush with the opening of the package cover semi-finished product, finally the opening of the package cover semi-finished product is sealed and fixed using the cover plate 1, and the degassing pipe 6 is installed at the through hole of the cover plate 1, the assembly is completed, and the installation mode of the bottom plate 8 and the outer side plate 7, the cover plate 1 and the outer side plate 7 and the cover plate 1 and the degassing pipe 6 is all welding fixed;

[0055] (3) the assembled package cover is sent into a vacuum degassing furnace, the temperature is increased to 350 DEG C, the temperature increasing rate is 10 DEG C / min, and the temperature is kept for 3 h, in the process, the package cover is vacuumized, until the vacuum degree reaches 1.0×10 -3 Pa;

[0056] (4) the package cover after degassing is assembled into a HiP device, then hot isostatic pressing is carried out, argon is used as pressure medium, the hot pressing temperature is 650 DEG C, the pressure is 130 Mpa, and the temperature keeping and pressure keeping time is 2 h, and the temperature increasing rate is 2 DEG C / min;

[0057] (5) after furnace cooling, the package cover is taken out, the package cover is cut open, the welded sample is taken out, the surface is treated clean, and the beryllium copper-tool steel diffusion welded finished product is obtained.

[0058] The tensile strength of the welded sample is measured by using a universal electronic tensile testing machine, and the welding surface bonding rate is measured by using an ultrasonic flaw detector, and the detection data are shown in Table 1.

[0059] As shown in the data in Table 1, the beryllium copper-tool steel diffusion welded finished product prepared by the present application has a higher welding surface bonding rate and good tensile strength.

[0060] Table 1

[0061]

[0062] The above is only the preferred embodiment of the present application, and is not used to limit the present application, and the present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A diffusion welding method for beryllium copper and tool steel, characterized in that, Includes the following steps: (1) Grind and polish the welded surfaces of beryllium copper and tool steel until smooth, then clean them; (2) The beryllium copper and tool steel are packed into the sleeve for assembly; (3) The assembled package is sent into a vacuum degassing furnace, and the temperature is set to 300~350℃. During this process, the package is evacuated to a vacuum degree of 2×10. -3 ~1×10 -4 pa; (4) Place the degassed package into a hot isostatic pressing equipment and then perform hot isostatic pressing. The protective gas is used as the pressure medium. The hot pressing temperature is 600~650℃, the pressure is 100~130Mpa, and the heat and pressure holding time is 2~4h. (5) After hot isostatic pressing is completed, the furnace is cooled down and then taken out of the furnace. The cladding is cut open to obtain the beryllium copper-tool steel diffusion welded finished product.

2. The diffusion welding method as described in claim 1, characterized in that, In step (1), the welding surfaces of beryllium copper and tool steel are mechanically ground and polished to a smooth finish.

3. The diffusion welding method as described in claim 1, characterized in that, The cleaning method in step (1) is as follows: first pickling, and then ultrasonic cleaning of the welding surface using organic solvent.

4. The diffusion welding method as described in claim 1, characterized in that, In step (3), the heating rate is 5~10℃ / min and the holding time is 3~5h.

5. The diffusion welding method as described in claim 1, characterized in that, In step (4), the heating rate is 2~5℃ / min.

6. The diffusion welding method according to any one of claims 1 to 5, characterized in that, In step (2), the package includes a bottom plate, an outer plate, a support plate, graphite paper, a cover plate, and a degassing pipe. The bottom plate is installed at the bottom of the outer plate, and the cover plate is installed at the top of the outer plate. The cover plate has a through hole, and the degassing pipe is installed at the through hole. The support plate and graphite paper are placed in the accommodating space formed by the bottom plate, the outer plate, and the cover plate.

7. The diffusion welding method as described in claim 6, characterized in that, The assembly process is as follows: Assemble the base plate and outer side plate to form a semi-finished sleeve with one end open. Place graphite paper on the side wall and bottom of the semi-finished sleeve. Then, place the support plate, graphite paper, beryllium copper, and tool steel in a cycle unit in sequence. The order of beryllium copper and tool steel in the cycle unit can be changed. After the last cycle unit is placed, place the support plate and graphite paper in sequence. Finally, use a cover plate to seal and fix the opening of the semi-finished sleeve, and install a degassing pipe at the through hole of the cover plate to complete the assembly.

8. The diffusion welding method as described in claim 7, characterized in that, The top graphite paper is flush with the opening of the semi-finished packaging.

9. The diffusion welding method as described in claim 7, characterized in that, The bottom plate and outer side plate, the top plate and outer side plate, and the top plate and degassing pipe are all installed by welding.

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