CN119433364B

CN119433364B - Preparation method of kovar alloy foil

Info

Publication number: CN119433364B
Application number: CN202411557633.2A
Authority: CN
Inventors: 韩钟剑; 马静; 罗文鹏; 苏辉; 汪道儒; 王祥
Original assignee: Xi'an Gangyan Special Alloy Co ltd
Current assignee: Xi'an Gangyan Special Alloy Co ltd
Priority date: 2024-11-04
Filing date: 2024-11-04
Publication date: 2025-06-10
Anticipated expiration: 2044-11-04
Also published as: CN119433364A

Abstract

The invention belongs to the technical field of kovar alloy foil preparation, and aims to solve the problems that in the prior art, the content control difficulty of trace elements is high and the content of harmful trace elements is difficult to further reduce in the kovar alloy foil preparation process. The invention provides a preparation method of a kovar alloy foil, which comprises the steps of placing a kovar alloy raw material into a smelting furnace for smelting, pouring molten metal into a target die to form a steel ingot, heating the steel ingot, forging the steel ingot into a blank, cooling the forged blank, cleaning the surface of the forged blank, dehydrogenating the blank after the surface is cleaned, and carrying out one-time hot rolling treatment and multiple-time cold rolling treatment on the dehydrogenated alloy to obtain the kovar alloy foil with the target thickness. The method ensures that the content of trace elements is accurately controlled during the preparation of the kovar alloy foil, reduces the content of harmful trace elements such as sulfur, avoids the hydrogen embrittlement problem of the kovar alloy, and improves the ductility and toughness of the kovar alloy.

Description

Preparation method of kovar alloy foil

Technical Field

The invention relates to the technical field of preparation of kovar alloy foil, in particular to a preparation method of a kovar alloy foil.

Background

The kovar alloy is a special alloy material with excellent performance, is widely applied to the fields of electronics, aviation, aerospace, precision instruments and the like, and particularly has outstanding importance in occasions needing high stability and low expansion coefficient. With the advancement of technology and the deep application, higher requirements are put on the performance and the preparation process of the kovar alloy foil, especially in the aspects of thickness uniformity, component purity, microstructure and the like of the foil.

The existing preparation method of the kovar alloy foil often has many challenges, such as inaccurate component control, poor structure uniformity caused by simple steel ingot casting and forging processes, easy generation of internal stress and impurity residues during sintering and the like, which directly affect the performance and service life of the final product, especially the content control of trace elements in the preparation process is important for improving the overall performance of the alloy, however, in the preparation process of the kovar alloy, it is unrealistic to completely eliminate some harmful trace elements, taking sulfur (S) as an example, the excessively high sulfur content can lead to remarkable reduction of the corrosion resistance and mechanical performance of the alloy, and according to research, even if the S content in the kovar alloy is very small, the problem of hydrogen embrittlement of the kovar alloy is possibly caused, because the S can promote the hydrogen absorption capacity of the metal, more hydrogen atoms can enter the metal, and because the S reduces the ductility and toughness of the metal, so that the material is easier to break when the material is subjected to the influence of hydrogen embrittlement, meanwhile, the S can promote the diffusion and aggregation of the hydrogen atoms in the metal, thereby further aggravating the problem of the trace elements in the preparation process is difficult to control how the hydrogen embrittlement of the trace elements in the preparation process.

In view of this, there is a need in the art for a new method of preparing kovar foil to address the above-mentioned problems.

Disclosure of Invention

In order to solve the technical problems, namely the problems that the control difficulty of trace element content is high and the harmful trace element content is difficult to further reduce in the preparation process of the kovar alloy foil in the prior art, the invention provides the preparation method of the kovar alloy foil, which aims to accurately control the trace element content in the preparation process of the kovar alloy foil, further reduce the content of the harmful trace element such as sulfur, avoid the hydrogen embrittlement problem of the kovar alloy and improve the ductility and toughness of the kovar alloy.

The invention provides a preparation method of a kovar alloy foil, which comprises the following steps:

S1, placing a kovar alloy raw material into a smelting furnace for smelting, and pouring molten metal into a target mould to form a steel ingot, wherein the mass percentage of trace element S components in the kovar alloy raw material is controlled to be less than or equal to 0.01 percent;

s2, heating the steel ingot prepared in the step S1 and forging the steel ingot into a blank;

S3, cooling the blank forged in the step S2, and cleaning the surface of the blank;

s4, carrying out dehydrogenation treatment on the blank with the cleaned surface in the step S3;

And S5, carrying out one-time hot rolling treatment and multiple-time cold rolling treatment on the alloy subjected to the dehydrogenation treatment in the step S4 to obtain the kovar alloy foil with the target thickness.

In certain preferred embodiments, the composition of the kovar alloy feedstock comprises ：C≤0.015％,P≤0.01％,S≤0.01％,Mn：0.35-0.45％,Si≤0.20％,Cu≤0.10％,Cr≤0.10％,Mo≤0.10％,N i：28.8％-29.2％,Co：17.0-17.3％,Zr：0.1-0.2％,Nb：0.05-0.15％, mass percent balance Fe.

In some preferred embodiments, the smelting temperature is 1600-1700 ℃, smelting is carried out under the protection of argon, the molten metal is kept for 10-15 minutes under the environment of 10-50Pa of vacuum degree before casting, then argon is introduced into the molten metal for blowing and stirring, the argon flow is controlled to be 5-10L/min, the stirring time is 5-8 minutes, the casting temperature is 1550-1600 ℃, the casting speed is 2-5kg/s, and the target mould is subjected to heat preservation treatment in the casting process.

In certain preferred embodiments, step S2 specifically comprises:

heating the steel ingot prepared in the step S1, firstly heating the steel ingot to 550-600 ℃ at a heating rate of 60-80 ℃ per hour for preheating, keeping the temperature for 2-3 hours, then heating to 1150-1200 ℃ at a heating rate of 100-120 ℃ per hour, and controlling the oxygen content in the furnace to be below 0.05% through a furnace gas circulation device in the heating process;

And forging the steel ingot into a required blank shape step by adopting a forging mode with multiple passes and small deformation, wherein the deformation of each pass is controlled between 12% and 18%.

In certain preferred embodiments, step S3 specifically comprises:

slowly cooling the blank in a holding furnace at a cooling speed of 60-80 ℃ per hour;

polishing the blank by mechanical polishing, wherein the polishing pressure is 0.2-0.4MPa, and the polishing speed is 10-15m/min;

Placing the blank into a chemical cleaning tank and cleaning by adopting cleaning liquid for 15-25 minutes, wherein the cleaning liquid is stirred at a stirring speed of 30-50r/min in the cleaning process;

after cleaning, the blank is rinsed with clean water under the rinsing pressure of 0.1-0.3MPa for 3-5 min.

In certain preferred embodiments, step S4 specifically comprises:

Placing the blank with the surface cleaned in the step S3 in a dehydrogenation furnace, and filling argon into the dehydrogenation furnace;

Heating and dehydrogenating the alloy in a dehydrogenation furnace at 1430-1480 ℃ for 2.5-3.5 hours;

after dehydrogenation is completed, the dehydrogenation furnace is powered off, and the alloy is naturally cooled to room temperature in the dehydrogenation furnace.

In certain preferred embodiments, step S4 further comprises:

polishing the dehydrogenated alloy by using a polishing machine, wherein the polishing direction is unchanged all the time;

and polishing the polished alloy by adopting a polishing machine.

In certain preferred embodiments, step S5 specifically comprises:

carrying out hot rolling treatment on the alloy subjected to the dehydrogenation treatment in the step S4, wherein the hot rolling treatment temperature is 410-430 ℃, and the hot rolling time is 70-80 minutes;

and carrying out multiple cold rolling, cleaning and annealing steps on the alloy after hot rolling, wherein the annealing temperature after the first cold rolling is 470-480 ℃, the annealing time is 65-75 minutes, and the cleaning adopts dilute hydrochloric acid.

In certain preferred embodiments, the hot rolled alloy is subjected to three cold rolling, cleaning and annealing steps, in particular:

Delivering the hot rolled alloy into a rolling mill for first rolling, cleaning the rolled alloy by dilute hydrochloric acid, and then carrying out first annealing;

Delivering the alloy subjected to the first annealing into a rolling mill for carrying out second rolling, and washing the rolled alloy with dilute hydrochloric acid and then carrying out second annealing, wherein the annealing temperature is 780-790 ℃ and the annealing time is 60-70 minutes;

And (3) sending the alloy subjected to the second annealing into a rolling mill for third rolling, and carrying out third annealing on the rolled alloy after washing by dilute hydrochloric acid to obtain the kovar alloy foil with the target thickness, wherein the annealing temperature is 530-540 ℃ and the annealing time is 60-70 minutes.

In certain preferred embodiments, step S5 further comprises:

And cleaning the kovar alloy foil subjected to the third annealing by adopting an ultrasonic cleaner for 10-15 minutes, and then polishing.

The invention has the following beneficial effects:

According to the preparation method of the kovar alloy foil, provided by the invention, the factor possibly causing hydrogen embrittlement is reduced from the source by strictly controlling the mass percentage (S is less than or equal to 0.01%) of the trace element S in the kovar alloy raw material, the dehydrogenation treatment procedure is added in the preparation process, the hydrogen possibly existing in the alloy is further removed, the hydrogen content in the alloy is greatly reduced after the dehydrogenation treatment, the toughness and the ductility of the foil are improved, the foil can resist the action of external force more, hydrogen embrittlement fracture is not easy to occur in the use process, the service life of the kovar alloy foil is remarkably prolonged, the forging treatment is carried out after steel ingot casting, the structure of the alloy is fully refined and homogenized, and the uniformity of the structure is further improved through subsequent hot rolling and repeated cold rolling treatment. The invention can meet the production requirement by adopting a common smelting furnace and forging equipment through proper parameter adjustment and maintenance without special high-precision smelting equipment and complex powder treatment equipment, thereby greatly reducing the equipment cost.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and should not be construed as limiting the invention in any way, in which:

FIG. 1 is a flow chart of a method of preparing a kovar alloy foil of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

Based on the problems that the control difficulty of trace elements is high and the harmful trace elements are difficult to further reduce in the preparation process of the kovar alloy foil in the prior art, which is pointed out by the background technology, the invention provides a preparation method of the kovar alloy foil, which aims to accurately control the trace elements in the preparation process of the kovar alloy foil, further reduce the content of the harmful trace elements such as sulfur, avoid the hydrogen embrittlement problem of the kovar alloy and improve the ductility and toughness of the kovar alloy.

As shown in fig. 1, the preparation method of the kovar alloy foil provided by the invention comprises the following steps:

S1, placing a kovar alloy raw material into a smelting furnace for smelting, and pouring molten metal into a target mould to form a steel ingot, wherein the mass percentage of trace element S in the kovar alloy raw material is controlled to be less than or equal to 0.01%, and preferably, other components are ：C≤0.015％,P≤0.01％,Mn：0.35-0.45％,S i≤0.20％,Cu≤0.10％,Cr≤0.10％,Mo≤0.10％,N i：28.8％-29.2％,Co：17.0-17.3％,Zr：0.1-0.2％,Nb：0.05-0.15％, as follows and the balance is Fe;

In the above, the content of manganese (Mn) is controlled to be between 0.35 and 0.45 percent, thereby playing the roles of deoxidizing and desulfurizing, being capable of being combined with sulfur to form high-melting-point manganese sulfide, reducing the harmful influence of sulfur, improving the strength and hardness of the alloy, and not affecting the toughness of the alloy, the content of chromium (Cr) is controlled to be less than or equal to 0.10 percent, the chromium can improve the corrosion resistance and the oxidation resistance of the kovar alloy, at high temperature, the chromium can form a stable chromium oxide film to prevent the alloy from being further oxidized, the content of molybdenum (Mo) is controlled to be less than or equal to 0.10 percent, the molybdenum can improve the strength and the high-temperature performance of the kovar alloy, can be dissolved in an alloy matrix, the interatomic bonding force of the alloy is enhanced, thereby improving the strength and the hardness of the alloy, meanwhile, the recrystallization temperature of the alloy can be improved, and the toughness of the alloy can be still kept better at high temperature, the content of zirconium (Zr) is controlled to be between 0.1 and 0.2 percent, the zirconium mainly plays the role of refining grains in the kovar alloy, the role of inhibiting the growth of the alloy in the solidification process, the alloy can enable the alloy to form a more uniform structure, the corrosion resistance of the alloy to be more stable, the corrosion resistance of the alloy can be improved, and the corrosion resistance of the alloy can be reduced, and the corrosion resistance of the alloy can be better than 15 percent, and the corrosion resistance of the alloy can be better to be controlled to have the toughness and stable to be more stable to the alloy.

In addition, the inventor discovers that the nickel (N i) and cobalt (Co) with the contents can form a stable austenite structure together, so that the alloy has good toughness and plasticity at room temperature, the nickel enlarges an austenite phase region, the cobalt improves the heat stability and strength of the alloy, and the nickel and the cobalt are matched with each other, so that the comprehensive mechanical property of the alloy is enhanced. The synergistic effect is more obvious, the alloy can keep better strength and hardness, deformation and softening are not easy to occur, when the sulfur content is controlled at a lower level (less than or equal to 0.01%), manganese can be combined with sulfur to form high-melting-point manganese sulfide, the harmful influence of sulfur is reduced, the occurrence of hot shortness phenomenon is prevented, the synergistic effect is beneficial to improving the mechanical property and the processing property of the alloy, the defects caused by sulfur are reduced, zirconium (Zr) and niobium (Nb) can mutually promote in the aspect of refining grains, the zirconium can inhibit the growth of grains in the solidification process in the alloy, so that the structure is more uniform and compact, the strength and the toughness of the alloy are improved, niobium forms stable compounds with elements such as carbon, nitrogen and the like, the adverse influence of the alloy performance is reduced, meanwhile, the grains can be refined, the mechanical property and the processing property of the alloy are further enhanced, the refined grains can enable the alloy to be easier to deform in the subsequent forging and rolling processes of the alloy, the dimensional accuracy and the surface accuracy are improved, the service life of the alloy is prolonged, and the corrosion resistance of the alloy is also improved.

Preferably, in the step S1, the smelting temperature is 1600-1700 ℃, smelting is carried out under the protection atmosphere of argon gas to prevent alloy oxidization and suction, high-quality molten metal is provided for subsequent working procedures, H13 steel is selected as a die, fine grinding and polishing treatment is carried out on the inner surface of the die to ensure that the surface roughness Ra is between 0.8 and 1.6 mu m, the surface smoothness of a steel ingot is ensured, stress concentration points in subsequent processing are reduced, a layer of high-temperature resistant release agent such as boron nitride coating is coated on the inner wall of the die, the thickness of the coating is controlled to be between 0.05 and 0.1mm, the demolding of the steel ingot is facilitated, the adhesion between the steel ingot and the die can be reduced, the possibility of surface defects is reduced, and the method such as air blowing stirring or vacuum treatment can be adopted for fully degassing the smelted molten metal. For example, firstly, the metal liquid is kept for 10-15 minutes under the environment with the vacuum degree of 10-50Pa, then argon is introduced into the metal liquid for blowing stirring, the argon flow is controlled to be 5-10L/min, the stirring time is 5-8 minutes, the hydrogen content in the metal liquid is reduced as much as possible, the generation of hydrogen embrittlement is prevented, the casting temperature is controlled to be in a proper range and is generally slightly higher than the liquidus temperature of alloy, for kovar alloy, the casting temperature is controlled to be 1550-1600 ℃, the metal liquid is ensured to have good fluidity, but the high fluidity leads to aggravation of inspiration and oxidization, the metal liquid smoothly flows into a mould during casting, the casting speed is controlled to be 2-5kg/s by adopting a bottom casting mode, the splashing and turbulence are avoided, the air and impurities are prevented from being involved, and in the casting process, the mould is subjected to heat preservation measures, such as adopting heat preservation materials (such as aluminum silicate fiber) to wrap the outside the mould, the thickness of the heat preservation layer is controlled to be 30-50mm, the cooling speed of steel ingot is slowed down, the internal structure of the steel ingot is more uniform, and the internal stress caused by uneven cooling is reduced;

preferably, the step S2 specifically includes:

Heating the steel ingot prepared in the step S1, firstly heating the steel ingot to 550-600 ℃ at a heating rate of 60-80 ℃ per hour for preheating, keeping the temperature for 2-3 hours, and then heating to a forging temperature range at a heating rate of 100-120 ℃ per hour, wherein the forging heating temperature is controlled to 1150-1200 ℃; in the heating process, the furnace atmosphere is ensured to be uniform, the oxygen content in the furnace is controlled below 0.05 percent through a furnace gas circulation device to prevent the ingot from being partially oxidized or decarburized, a multi-pass forging mode with small deformation is adopted to gradually forge the ingot into a required blank shape, the deformation of each pass is controlled between 12 and 18 percent, for example, rough forging is firstly carried out to forge the ingot shape approximately to the shape of a blank, the rough forging passes are 3 to 5 times, then finish forging is carried out for a plurality of times, the finish forging passes are 5 to 8 times, the structure is gradually thinned and the dimensional accuracy is improved, in the forging process, the forging direction and the deformation sequence are controlled to ensure that the blank can be fully deformed in different directions, for example, axial forging is firstly carried out, then radial forging is carried out, the reduction of each forging is controlled between 10 and 20mm, the good forging effect can be ensured at all parts of the blank, the striking force and the frequency of forging equipment are controlled, the hydraulic press is adopted to forge the blank with a hydraulic press for a large volume, the blank with the hydraulic press pressure is controlled between 100 and 150MPa, the mechanical hammer is used for a small volume, the forging force is controlled between the forging force and 500 kN for a large striking force is controlled between 500 min and 50/500 m, and the striking force of the blank is avoided, meanwhile, proper frequency can ensure the stable forging process;

Preferably, step S3 specifically includes:

After forging, the blank is cooled, preferably by adopting a slow cooling mode, such as placing the blank in a heat preservation furnace to cool slowly along with the furnace, wherein the cooling speed is controlled to be about 60-80 ℃ per hour, or the blank is wrapped by heat preservation materials such as asbestos and the like to cool, the thickness of the heat preservation materials is controlled to be 20-30mm, so that the cooling speed is reduced, and residual stress and tissue non-uniformity caused by too fast cooling are reduced; the method comprises the steps of carrying out surface cleaning by combining mechanical polishing and chemical cleaning, firstly, carrying out preliminary polishing removal on oxide skin on the surface of a blank by using tools such as a grinding wheel or a steel wire brush, controlling the polishing pressure to be between 0.2 and 0.4MPa, controlling the polishing speed to be between 10 and 15m/min, then placing the blank into a chemical cleaning tank for cleaning, selecting a solution containing a proper amount of acid and corrosion inhibitor such as dilute hydrochloric acid (with the concentration of 8-10%) or sulfuric acid solution (with the concentration of 6-8%), wherein the addition amount of the corrosion inhibitor is 0.8-1% of the mass of the acid solution, determining the cleaning time to be generally 15-25 minutes according to the thickness and the pollution degree of the oxide skin on the surface of the blank, continuously stirring the cleaning liquid at the stirring speed of 30-50r/min to ensure uniform cleaning and prevent excessive corrosion on the surface of the blank, washing the blank, carrying out washing by using clear water after washing, carrying out washing the blank for 3-5 minutes at the washing pressure of 0.5 to 0.5 MPa, removing residual cleaning liquid and impurities on the surface, then carrying out drying treatment at the temperature of 90-110 ℃ for 1.5-2 hours, ensuring that the surface is clean, preparing for subsequent flaw detection and processing procedures, comprehensively detecting the cleaned blank by adopting various flaw detection methods to ensure the internal quality of the blank, for example, firstly detecting whether the blank has flaws such as cracks and looseness by using an ultrasonic flaw detector, wherein the frequency of ultrasonic flaw detection is generally between 2.5 and 4MHz according to the size and the material of the blank, detecting the large-volume blank by adopting a plurality of probes and a plurality of angles, controlling the spacing between the probes to be between 50 and 80mm to ensure the full detection coverage, then performing magnetic powder flaw detection, detecting the micro-defects on the surface and the near surface of the blank, uniformly spraying magnetic powder suspension on the surface of the blank after magnetizing the blank, ensuring the concentration of the magnetic powder to be 10 to 20g/L, observing the aggregation condition of the magnetic powder, judging whether the defects exist, controlling the magnetizing current and the magnetic field strength to be within a proper range when the magnetic powder flaw detection is performed, analyzing and evaluating the flaws found by the flaw detection by the ultrasonic flaw detection, and if the surface micro-defect size is less than 2mm, repairing the flaw by adopting a polishing and repair method, and the repair method if the internal size is more than 5mm, and the defect is required to be repaired to be more seriously, and the defect is required to be repaired is more seriously;

preferably, step S4 specifically includes:

Placing the blank with the cleaned surface in the step S3 in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating and dehydrogenating the alloy in the dehydrogenation furnace at 1430-1480 ℃ for 2.5-3.5 hours, turning off a power supply of the dehydrogenation furnace after the dehydrogenation is completed and naturally cooling the alloy to room temperature in the dehydrogenation furnace;

S5, performing primary hot rolling treatment and multiple cold rolling treatment on the alloy subjected to the dehydrogenation treatment in the step S4 to obtain a kovar alloy foil with the target thickness;

Preferably, step S5 specifically includes:

Carrying out hot rolling treatment on the alloy subjected to the dehydrogenation treatment in the step S4, wherein the hot rolling treatment temperature is 410-430 ℃, the hot rolling time is 70-80 minutes, and the blank is further deformed through hot rolling, so that the structure performance is improved, and the preparation is carried out for the subsequent cold rolling process; the method comprises the steps of carrying out multiple cold rolling, cleaning and annealing on the alloy after hot rolling, wherein the annealing temperature after the first cold rolling is 470-480 ℃, the annealing time is 65-75 minutes, the cleaning adopts dilute hydrochloric acid for cleaning, the special explanation is that the texture in the alloy after hot rolling is converted into weaker random diffuse texture, and the special texture variant with the crystal face index of 100 and the crystal direction index of 110 is optimal in terms of comprehensive mechanical property and anisotropism, and obviously reduces the plastic anisotropism while ensuring the strength of the material compared with the annealing parameter settings with the annealing temperature range with the excessively high temperature (leading to the oversize of crystal grain size and the reduction of the strength and hardness of the material) and the annealing temperature range with the excessively low temperature (leading to incomplete crystallization, dislocation and substructure, leading to the reduction of plasticity, the deterioration of toughness and the increase of crack growth) after the hot rolling;

The method comprises the steps of cold rolling, cleaning and annealing the hot rolled alloy for three times, specifically, the hot rolled alloy is sent to a rolling mill for first rolling, the rolled alloy is cleaned by dilute hydrochloric acid and then annealed for the first time, the alloy after the first annealing is sent to the rolling mill for second rolling, the rolled alloy is cleaned by dilute hydrochloric acid and then annealed for the second time, wherein the annealing temperature is 780-790 ℃ and the annealing time is 60-70 minutes, the alloy after the second annealing is sent to the rolling mill for third rolling, the rolled alloy is cleaned by dilute hydrochloric acid and then annealed for the third time to obtain the kovar alloy foil with the target thickness, the annealing temperature is 530-540 ℃ and the annealing time is 60-70 minutes, and the kovar alloy foil after the third annealing is cleaned by an ultrasonic cleaner for 10-15 minutes and then polished.

After the repeated experiments by the inventor, Analysis and comparison show that S has certain surface activity in the alloy, and when the S content is higher (more than 0.01%), the S is enriched on the surface of the alloy liquid to a higher degree; in the smelting and pouring process, the alloy liquid contacts with surrounding atmosphere, S can change the physical and chemical properties of the alloy liquid surface, so that hydrogen is easier to adsorb on the alloy liquid surface, the S atoms and hydrogen molecules can form a certain weak chemical bond or physical adsorption effect, the dissolution and adsorption probability of hydrogen in the alloy liquid are increased, compared with the S content which is controlled below 0.01%, the enrichment degree of the S in the alloy liquid surface is obviously reduced, the adsorption capacity of the alloy liquid surface to hydrogen is weakened, the amount of hydrogen entering the alloy liquid is reduced, in addition, the structure and property of an oxide film on the alloy surface can be influenced when the S content is higher, the alloy can react with oxygen in air to form an oxide film in the high-temperature smelting process, more defects and pores can exist in the oxide film containing the S, the defects provide permeation channels for the hydrogen, the hydrogen can diffuse into the alloy more easily through the channels, the hydrogen content in the alloy is increased, when the S content is controlled below 0.01%, the formed oxide film is more uniform and even, the adsorption capacity of the hydrogen can not enter the alloy liquid, the oxygen content can be effectively blocked by the oxygen in the vacuum treatment, the oxygen can not influence the vacuum treatment can be reduced, the oxygen in the vacuum treatment can be effectively removed, the vacuum treatment can be carried out, the oxygen can not generate the vacuum treatment can be carried out, the oxygen can be further, the degassing effect is better, the vacuum treatment can be carried out, the degassing effect is better, and other impurities can be removed, and the like can be better removed, and the like, the compounds are not easy to volatilize and discharge in a vacuum environment, so that the removal efficiency of hydrogen is affected; in the process of blowing and stirring, S can chemically react with argon, partial argon is consumed, meanwhile, the generated product can be wrapped around the hydrogen bubbles, the rising and discharge of the hydrogen bubbles are prevented, the degassing effect is poor, the hydrogen content in the alloy is finally high, when the S content in the raw material is controlled below 0.01%, interference factors in the degassing process are reduced, vacuum treatment can effectively remove the hydrogen in the alloy liquid, because excessive S related compounds prevent volatilization of the hydrogen, when blowing and stirring, the argon can be more smoothly contacted with the alloy liquid, the hydrogen dissolved in the alloy liquid is brought out, the degassing efficiency is improved, the hydrogen content in the alloy can be better controlled, in the subsequent processing processes such as forging and rolling, the atoms in the alloy can be moved and rearranged, when the S content in the raw material is high, the alloy is easier to produce stress concentration and micro defects in the processing process, defect positions can become aggregation points of the hydrogen, the hydrogen can be more effectively removed, the hydrogen can be prevented from being aggregated at the defect positions, the hydrogen content can not be more than excessive S content, the hydrogen content in the alloy is better in the processing process, the defect positions can be more evenly influenced, the hydrogen content in the alloy is better than 0.01%, the alloy is better in the processing process, the defect is better in the processing process, the hydrogen is better in the alloy is more evenly distributed, the alloy is better than 0.01%, the alloy is better in the alloy, the alloy is better in the processing process, the alloy is better in the alloy, the quality is better in the processing process, and has better effects of the alloy is better than 0% and has better effects, and better effects, when the effect can be better effects can be better and better, and have better effects can be better quality, can react with gas generated in the dehydrogenation process or other elements in the alloy to form stable compounds which can inhibit the removal of hydrogen, for example, S can form stable hydride with hydrogen in the alloy, so that the dehydrogenation process can achieve the same dehydrogenation effect at a higher temperature for a longer time, conversely, when the S content is controlled below 0.01%, the dehydrogenation process is smoother, and under the same dehydrogenation treatment condition (such as dehydrogenation temperature and time), the hydrogen in the alloy can be removed more effectively, the hydrogen content is reduced to a lower level, and the quality and performance stability of the kovar alloy foil are improved.

The technical scheme of the invention is further described below by combining a plurality of embodiments:

Example 1

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are ：C＝0.015％,P＝0.01％,S＝0.01％,Mn＝0.35％,Si＝0.20％,Cu＝0.10％,Cr＝0.10％,Mo＝0.10％,N i＝28.8％,Co＝17.0％,Zr＝0.1％,Nb＝0.05％, mass percent and the balance is Fe;

Placing the kovar alloy raw material into a smelting furnace, smelting at 1600 ℃, adopting argon protection atmosphere in the smelting process, adopting H13 steel as a mould, carrying out fine grinding and polishing treatment on the inner surface of the mould to enable the surface roughness Ra to reach 0.8 mu m, coating boron nitride paint on the inner wall of the mould to enable the thickness of the coating to be 0.05mm, firstly keeping the smelted molten metal in the environment with the vacuum degree of 10Pa for 10min for preliminary vacuum treatment, then introducing argon into the molten metal for blowing and stirring, controlling the flow rate of the argon to be 5L/min, controlling the stirring time to be 5min, controlling the casting temperature to be 1550 ℃, adopting a bottom pouring mode, controlling the casting speed to be 2kg/s, wrapping the outer part of the mould by aluminum silicate fiber, and controlling the thickness of a heat preservation layer to be 30mm;

Heating a steel ingot to 550 ℃ at a heating rate of 60 ℃ per hour for preheating, keeping the temperature for 2 hours, heating to 1150 ℃ at a heating rate of 100 ℃ per hour for forging, performing rough forging for 3 times and then finish forging for 5 times, wherein the forging equipment is a hydraulic press, the pressure is controlled to be 100MPa, performing axial forging in the forging process, controlling the rolling reduction of each forging to be 10mm, performing radial forging, controlling the rolling reduction of each forging to be 10mm, and after the forging is finished, placing the blank in a heat preservation furnace for slow cooling along with the furnace, wherein the cooling speed is controlled to be 60 ℃ per hour;

Firstly polishing and removing oxide skin on the surface of a blank by using a grinding wheel, wherein the polishing pressure is 0.2MPa, the polishing speed is 10m/min, then placing the blank into a chemical cleaning tank, cleaning liquid is dilute hydrochloric acid (concentration is 8%), corrosion inhibitor (0.8% of the mass of acid liquor) is added, the cleaning time is 15 minutes, the stirring speed is 30r/min in the cleaning process, after cleaning, the blank is washed by clean water, the flushing pressure is 0.1MPa, the flushing time is 3 minutes, finally drying at 90 ℃ for 1.5 hours, firstly using an ultrasonic flaw detector to detect the blank, the ultrasonic flaw detection frequency is 2.5MHz, and for a large-volume blank, the multi-probe and multi-angle flaw detection are adopted, the probe spacing is controlled at 50mm, then carrying out magnetic powder flaw detection, the magnetic powder concentration is 10g/L, the magnetizing current is 500A, the magnetic field strength is 2000Gs, if the surface tiny flaw (the flaw size is less than 2 mm), repairing is adopted, if the internal bigger flaw (the flaw size is more than 5mm or the flaw depth exceeds 10% of the blank thickness) is found, the blank is scrapped, and the repaired part is detected again;

Placing the cooled blank in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating to 1430 ℃ for dehydrogenation treatment, and naturally cooling to room temperature along with the furnace after dehydrogenation, polishing the alloy after dehydrogenation treatment by a polisher, wherein the polishing direction is unchanged all the time;

The alloy after dehydrogenation treatment is subjected to hot rolling treatment at the temperature of 410 ℃ for 70 minutes, the alloy after hot rolling is subjected to three times of cold rolling, cleaning and annealing, the alloy after hot rolling is annealed at 470 ℃ for 65 minutes after the first cold rolling, is annealed at 780 ℃ for 60 minutes after the second cold rolling, is annealed at 530 ℃ for 60 minutes after the third cold rolling, and the kovar alloy foil with the target thickness is obtained, and the foil after the third annealing is cleaned by an ultrasonic cleaner for 10 minutes and then is polished.

Example two

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are ：C＝0.01％,P＝0.005％,S＝0.005％,Mn＝0.4％,Si＝0.15％,Cu＝0.08％,Cr＝0.08％,Mo＝0.08％,N i＝29％,Co＝17.15％,Zr＝0.15％,Nb＝0.1％, mass percent and the balance is Fe;

Placing the kovar alloy raw material into a smelting furnace, smelting at 1650 ℃ under the protection of argon, finely grinding and polishing the inner surface of a die made of H13 steel to enable the surface roughness Ra to reach 1.2 mu m, coating boron nitride paint on the inner wall of the die to enable the thickness of the coating to be 0.08mm, firstly keeping the smelted molten metal in the environment with the vacuum degree of 30Pa for 12 minutes for preliminary vacuum treatment, then introducing argon into the molten metal for blowing and stirring, controlling the flow rate of the argon to be 8L/min, the stirring time to be 6 minutes, controlling the casting temperature to be 1580 ℃, adopting a bottom casting mode, controlling the casting speed to be 3kg/s, wrapping the outer part of the die by aluminum silicate fiber, and controlling the thickness of an insulating layer to be 40mm;

Heating a steel ingot to 580 ℃ at a heating rate of 70 ℃ per hour for preheating, keeping the temperature for 2.5 hours, heating to 1180 ℃ at a heating rate of 110 ℃ per hour for forging, performing rough forging for 4 times and then finish forging for 6 times, wherein the forging equipment is a hydraulic press, the pressure is controlled to 120MPa, performing axial forging in the forging process, controlling the forging reduction to 15mm each time, performing radial forging, controlling the forging reduction to 15mm each time, and wrapping a blank with an asbestos heat-insulating material for cooling after the forging is finished, wherein the thickness of the heat-insulating material is 25mm, and the cooling speed is controlled to 70 ℃ per hour;

Firstly polishing and removing oxide skin on the surface of a blank by using a steel wire brush, wherein the polishing pressure is 0.3MPa, the polishing speed is 12m/min, then placing the blank into a chemical cleaning tank, cleaning liquid is dilute sulfuric acid (concentration is 7%), corrosion inhibitor (0.9% of the acid liquor mass) is added, cleaning time is 20 minutes, stirring speed is 40r/min in the cleaning process, cleaning is carried out after cleaning, the cleaning pressure is 0.2MPa, the cleaning time is 4 minutes, finally drying at 100 ℃ for 1.8 hours, firstly using an ultrasonic flaw detector to detect the blank, the ultrasonic flaw detection frequency is 3MHz, adopting a multi-probe and multi-angle flaw detection for a large-volume blank, controlling the probe spacing to be 60mm, then carrying out magnetic powder flaw detection, the magnetic powder concentration is 15g/L, the magnetizing current is 600A, the magnetic field strength is 2500Gs, repairing is carried out by adopting a repair welding method if the surface tiny flaw (the flaw size is less than 2 mm), and carrying out scrapping detection on the repaired blank if the internal large flaw (the flaw size is more than 5mm or the flaw depth exceeds 10% of the blank thickness) is found;

Placing the cooled blank in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating to 1450 ℃ for dehydrogenation treatment, and naturally cooling to room temperature along with the furnace after dehydrogenation is completed, polishing the alloy after dehydrogenation treatment by a polisher, wherein a cross polishing mode is adopted (namely, polishing is carried out for a certain time along one direction and then polishing is carried out for the same time along the vertical direction) during polishing;

The alloy after dehydrogenation treatment is subjected to hot rolling treatment at 420 ℃ for 75 minutes, the alloy after hot rolling is subjected to three times of cold rolling, cleaning and annealing, the alloy after hot rolling is annealed at 475 ℃ for 70 minutes after the first cold rolling, is annealed at 785 ℃ for 65 minutes after the second cold rolling, is annealed at 535 ℃ for 65 minutes after the third cold rolling, and the kovar alloy foil with the target thickness is obtained, and the foil after the third annealing is cleaned for 12 minutes by an ultrasonic cleaner and then is polished.

Example III

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are ：C＝0.008％,P＝0.003％,S＝0.003％,Mn＝0.42％,Si＝0.12％,Cu＝0.06％,Cr＝0.06％,Mo＝0.06％,N i＝29.1％,Co＝17.2％,Zr＝0.18％,Nb＝0.12％, mass percent and the balance is Fe;

Placing the kovar alloy raw material into a smelting furnace, smelting at 1680 ℃ under the protection of argon, adopting H13 steel as a mould, finely grinding and polishing the inner surface of the mould to enable the surface roughness Ra to reach 1.4 mu m, coating boron nitride paint on the inner wall of the mould to enable the thickness of the coating to be 0.09mm, firstly keeping the smelted molten metal in the environment with the vacuum degree of 40Pa for 13 minutes for preliminary vacuum treatment, then introducing argon into the molten metal for blowing and stirring, controlling the flow rate of the argon to be 9L/min, controlling the stirring time to be 7 minutes, controlling the casting temperature to be 1590 ℃, adopting a bottom casting mode, controlling the casting speed to be 4kg/s, wrapping the outer part of the mould by aluminum silicate fiber, and controlling the thickness of an insulating layer to be 45mm;

Heating a steel ingot to 590 ℃ at a heating rate of 75 ℃ per hour for preheating, keeping the temperature for 2.8 hours, heating to 1190 ℃ at a heating rate of 115 ℃ per hour for forging, performing rough forging for 4 times and then finish forging for 7 times, wherein the forging equipment is a hydraulic press, the pressure is controlled to 130MPa, performing axial forging in the forging process, controlling the forging reduction to 18mm each time, performing radial forging, controlling the forging reduction to 18mm each time, and wrapping a blank with an asbestos heat-insulating material for cooling after the forging is finished, wherein the thickness of the heat-insulating material is 28mm, and the cooling speed is controlled to 75 ℃ per hour;

Firstly polishing and removing oxide skin on the surface of a blank by using a grinding wheel, wherein the polishing pressure is 0.35MPa, the polishing speed is 13m/min, then placing the blank into a chemical cleaning tank, cleaning liquid is dilute hydrochloric acid (concentration is 9%), corrosion inhibitor (0.95% of the mass of acid liquor) is added, cleaning time is 22 min, stirring speed is 45r/min in the cleaning process, after cleaning, cleaning is carried out by using clean water, the flushing pressure is 0.25MPa, the flushing time is 4 min, finally drying at 105 ℃ for 1.9 h, firstly using an ultrasonic flaw detector to detect the blank, the ultrasonic flaw detection frequency is 3.5MHz, and for a large-volume blank, a plurality of probes and a plurality of angles of flaw detection are adopted, the probe spacing is controlled at 70mm, then carrying out magnetic powder flaw detection, the magnetic powder concentration is 18g/L, the magnetic field strength is 700A, the magnetic field strength is 2800Gs, if the surface tiny flaw (the flaw size is less than 2 mm), repairing is carried out by adopting a polishing method, if the internal large flaw (the flaw size is more than 5mm or the flaw depth exceeds 10% of the thickness of the blank), and then carrying out flaw detection again after repairing;

Placing the cooled blank in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating to 1460 ℃ for dehydrogenation treatment, naturally cooling to room temperature along with the furnace after dehydrogenation, polishing the dehydrogenated alloy by adopting a polishing machine, polishing the polished alloy by adopting a spiral polishing path (from center to outside) by adopting a polishing machine, and periodically replacing polishing liquid in the polishing process to ensure the polishing effect;

The alloy after dehydrogenation treatment is subjected to hot rolling treatment at 425 ℃ for 78 minutes, the alloy after hot rolling is subjected to three times of cold rolling, cleaning and annealing, the alloy after hot rolling is annealed at 478 ℃ for 72 minutes after the first cold rolling, is annealed at 788 ℃ for 68 minutes after the second cold rolling, is annealed at 538 ℃ for 68 minutes after the third cold rolling, and the kovar alloy foil with the target thickness is obtained, and the foil after the third annealing is cleaned by an ultrasonic cleaner for 13 minutes and then is polished.

Example IV

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are ：C＝0.005％,P＝0.002％,S＝0.002％,Mn＝0.45％,Si＝0.1％,Cu＝0.05％,Cr＝0.05％,Mo＝0.05％,N i＝29.2％,Co＝17.3％,Zr＝0.2％,Nb＝0.15％, mass percent and the balance is Fe;

Placing the kovar alloy raw material into a smelting furnace, smelting at 1700 ℃, adopting an argon protection atmosphere in the smelting process, adopting H13 steel as a mould, carrying out fine grinding and polishing treatment on the inner surface of the mould to ensure that the surface roughness Ra reaches 1.6 mu m, coating boron nitride paint on the inner wall of the mould to ensure that the thickness of the coating is 0.1mm, carrying out preliminary vacuum treatment on the smelted molten metal in an environment with the vacuum degree of 50Pa for 15 minutes, then introducing argon into the molten metal for blowing and stirring, controlling the flow rate of the argon to be 10L/min, controlling the stirring time to be 8 minutes, controlling the casting temperature to be 1600 ℃, adopting a bottom pouring mode, controlling the casting speed to be 5kg/s, wrapping the outer part of the mould by aluminum silicate fiber, and controlling the thickness of a heat preservation layer to be 50mm;

heating a steel ingot to 600 ℃ at a temperature rising rate of 80 ℃ per hour for preheating, keeping the temperature for 3 hours, then heating to 1200 ℃ at a temperature rising rate of 120 ℃ per hour for forging, performing rough forging for 5 times and then finish forging for 8 times, wherein the forging equipment is a hydraulic press, the pressure is controlled to 150MPa, performing axial forging in the forging process, controlling the rolling reduction of each forging to 20mm, performing radial forging, controlling the rolling reduction of each forging to 20mm, and after the forging is completed, placing the blank in a heat preservation furnace for slow cooling along with the furnace, wherein the cooling speed is controlled to 80 ℃ per hour;

Firstly polishing and removing oxide skin on the surface of a blank by using a steel wire brush, wherein the polishing pressure is 0.4MPa, the polishing speed is 15m/min, then placing the blank into a chemical cleaning tank, cleaning liquid is dilute sulfuric acid (concentration is 8%), corrosion inhibitor (defect size is less than 2 mm) is added, cleaning time is 25 minutes, stirring speed is 50r/min in the cleaning process, cleaning is carried out by using clean water, the flushing pressure is 0.3MPa, the flushing time is 5 minutes, finally drying at 110 ℃ for 2 hours, firstly carrying out flaw detection on the blank by using an ultrasonic flaw detector, the ultrasonic flaw detection frequency is 4MHz, carrying out multi-probe and multi-angle flaw detection on a large-volume blank, the probe spacing is controlled at 80mm, then carrying out magnetic powder flaw detection, the magnetic powder concentration is 20g/L, the magnetizing current is 800A, the magnetic field strength is 3000Gs, if the surface micro defects (defect size is less than 2 mm) are found, then carrying out repair by adopting a repair welding method, and carrying out flaw detection on the repaired part again if the internal large defects (defect size is more than 5mm or defect depth exceeds 10% of the blank thickness);

Placing the cooled blank in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating to 1480 ℃ for dehydrogenation treatment, and naturally cooling to room temperature along with the furnace after dehydrogenation, polishing the alloy after dehydrogenation treatment by a polisher, dividing the surface of the blank into a plurality of areas for polishing in sequence, polishing the alloy after polishing by a polisher, and adjusting polishing parameters according to the surface condition of the blank in the polishing process;

The alloy after dehydrogenation treatment is subjected to hot rolling treatment at 430 ℃ for 80 minutes, the alloy after hot rolling is subjected to three times of cold rolling, cleaning and annealing, the alloy after hot rolling is annealed at 480 ℃ for 75 minutes after the first cold rolling, the alloy is annealed at 790 ℃ for 70 minutes after the second cold rolling, the alloy is annealed at 540 ℃ for 70 minutes after the third cold rolling, the kovar alloy foil with the target thickness is obtained, and the foil after the third annealing is cleaned for 15 minutes by an ultrasonic cleaner and then is polished.

Example five

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are ：C＝0.012％,P＝0.008％,S＝0.008％,Mn＝0.38％,Si＝0.18％,Cu＝0.09％,Cr＝0.09％,Mo＝0.09％,N i＝28.9％,Co＝17.1％,Zr＝0.12％,Nb＝0.08％, mass percent and the balance is Fe;

Placing the kovar alloy raw material into a smelting furnace, smelting at 1630 ℃ under the protection of argon, adopting H13 steel as a mould, finely grinding and polishing the inner surface of the mould to ensure that the surface roughness Ra reaches 1 mu m, coating boron nitride paint on the inner wall of the mould to ensure that the thickness of the coating is 0.06mm, firstly, keeping the smelted molten metal in the environment with the vacuum degree of 20Pa for 11 minutes for preliminary vacuum treatment, then introducing argon into the molten metal for blowing and stirring, controlling the flow rate of the argon to be 6L/min, controlling the stirring time to be 6 minutes, controlling the casting temperature to be 1560 ℃, adopting a bottom pouring mode, controlling the casting speed to be 3kg/s, wrapping the outer part of the mould by aluminum silicate fiber, and controlling the thickness of the heat preservation layer to be 35mm;

Heating a steel ingot to 560 ℃ at a heating rate of 65 ℃ per hour for preheating, keeping the temperature for 2.2 hours, then heating to 1160 ℃ at a heating rate of 105 ℃ per hour for forging, performing rough forging for 3 times and then finish forging for 6 times, wherein the deformation of each pass is controlled to be 13%, the pressure of the forging equipment is controlled to be 110MPa, in the forging process, performing axial forging, the rolling reduction of each forging is controlled to be 12mm, then performing radial forging, the rolling reduction of each forging is controlled to be 12mm, and after the forging is completed, wrapping a blank by using an asbestos heat-insulating material for cooling, wherein the thickness of the heat-insulating material is 22mm, and the cooling speed is controlled to be 65 ℃ per hour;

Firstly polishing and removing oxide skin on the surface of a blank by using a grinding wheel, wherein the polishing pressure is 0.25MPa, the polishing speed is 11m/min, then placing the blank into a chemical cleaning tank, cleaning liquid is dilute hydrochloric acid (the concentration is 8.5%), corrosion inhibitor (0.85% of the acid liquor mass) is added, the cleaning time is 18 min, the stirring speed is 35r/min in the cleaning process, after the cleaning, the cleaning pressure is 0.15MPa, the cleaning time is 3.5 min, finally drying at 95 ℃ for 1.6 h, firstly performing flaw detection on the blank by using an ultrasonic flaw detector, the ultrasonic flaw detection frequency is 2.8MHz, performing multi-probe multi-angle flaw detection on a large-volume blank, the probe spacing is controlled at 55mm, then performing magnetic powder flaw detection, the magnetic powder concentration is 12g/L, the magnetizing current is 550A, the magnetic field strength is 2200Gs, if the surface micro defects (the defect size is less than 2 mm) are found, repairing by adopting a polishing method, and if the internal large defects (the defect size is more than 5mm or the defect depth exceeds 10% of the blank thickness) are found, performing flaw detection again;

Placing the cooled blank in a dehydrogenation furnace, filling argon into the dehydrogenation furnace, heating to 1440 ℃ for dehydrogenation treatment, and naturally cooling to room temperature along with the furnace after dehydrogenation is completed, polishing the alloy after dehydrogenation treatment by a polisher, polishing the alloy after polishing by a reciprocating polishing mode (back and forth repeated polishing), and controlling the polishing temperature by a polisher in the polishing process;

The alloy after dehydrogenation treatment is subjected to hot rolling treatment at 415 ℃ for 72 minutes, the alloy after hot rolling is subjected to three times of cold rolling, cleaning and annealing, the alloy after hot rolling is annealed at 472 ℃ for 68 minutes after the first cold rolling, is annealed at 782 ℃ for 62 minutes after the second cold rolling, is annealed at 532 ℃ for 62 minutes after the third cold rolling, and the kovar alloy foil with the target thickness is obtained, and the foil after the third annealing is cleaned by an ultrasonic cleaner for 11 minutes and then is polished.

Comparative example one

Preparing a kovar alloy raw material, wherein the components of the kovar alloy raw material are similar to those of the embodiment, but the trace element S is not strictly controlled, the mass percentage of S is 0.02 percent (which is less than or equal to 0.01 percent than that of the embodiment), and the other main components are ：C＝0.012％,P＝0.008％,Mn＝0.38％,Si＝0.18％,Cu＝0.09％,Cr＝0.09％,Mo＝0.09％,N i＝28.9％,Co＝17.1％,Zr＝0.12％,Nb＝0.08％, and the balance is Fe;

placing the kovar alloy raw material into a common smelting furnace for smelting, wherein the smelting temperature is 1600 ℃, the common nitrogen protective atmosphere is adopted, the common die material is selected, the internal surface of the die is rough in grinding and polishing treatment, the surface roughness Ra is about 2 mu m, no special release agent is used for directly casting, the metal liquid is only subjected to simple blowing and degassing, no vacuum treatment is carried out, the casting temperature is 1550 ℃, the casting mode is upward injection (different from the bottom injection of the embodiment), the casting speed is higher, and the die has no heat preservation measure;

The surface cleaning only adopts simple mechanical polishing, then flaw detection is directly carried out, chemical cleaning is not carried out, an ultrasonic flaw detector is only used for flaw detection, and flaw detection frequency is fixed to be 3MHz;

Putting the blank into a dehydrogenation furnace, carrying out dehydrogenation treatment at 1400 ℃ for 2.5 hours, and filling argon in the dehydrogenation process;

the hot rolling treatment temperature is 410 ℃, the hot rolling time is 65 minutes, the cold rolling times are two, the annealing temperature after the first cold rolling is 450 ℃, the annealing time is 50 minutes, the annealing temperature after the second cold rolling is 510 ℃, the annealing time is 50-60 minutes, and the third cold rolling and the corresponding annealing treatment are not carried out.

Comparative example two

Preparing a kovar alloy raw material, wherein the kovar alloy raw material comprises the following components of C=0.015%, P=0.01%, S=0.015% (slightly higher than the embodiment), mn=0.35%, S i =0.20%, cu=0.10%, cr=0.10%, mo=0.10%, N i =28.8%, co=17.0%, zr=0.1%, nb=0.05% and the balance of Fe;

the preparation of the mold is similar to that of the embodiment, but in the casting process, degassing treatment is insufficient, only short blowing stirring is carried out, the argon flow is 4L/min, the stirring time is 4 minutes, the casting temperature is 1600 ℃, the casting speed is 4.5kg/s, bottom casting is adopted, but the thickness of a heat insulation layer of the mold is thinner, and the thickness of the heat insulation layer of the mold is about 25mm;

In the heating process, the preheating temperature is 530 ℃, the heat preservation time is 1.5 hours, the rate of heating to the forging temperature is 90 ℃ per hour, the forging temperature is 1150 ℃, the deformation of each pass is 20%, the rough forging pass is 3 times, the finish forging pass is 4 times, the forging equipment is a small hydraulic press, the pressure is controlled at 100MPa, and the cooling speed is higher after forging by adopting an air cooling mode;

During surface cleaning, the polishing pressure is 0.2MPa, the polishing speed is 10m/min, the chemical cleaning liquid is dilute hydrochloric acid (concentration is 7%), the addition amount of the corrosion inhibitor is 0.7% of the mass of the acid liquor, the cleaning time is 13 minutes, the stirring speed is 25r/min, in flaw detection, the ultrasonic flaw detection frequency is 3.5MHz, the probe spacing is 60mm, the magnetic powder concentration is 15g/L during magnetic powder flaw detection, the magnetizing current is 600A, and the magnetic field strength is 2500Gs;

Placing the blank into a dehydrogenation furnace, wherein the dehydrogenation temperature is 1440 ℃ and the dehydrogenation time is 2.5 hours;

The hot rolling treatment temperature is 420 ℃, the hot rolling time is 65 minutes, the cold rolling is twice, the annealing temperature after the first cold rolling is 470 ℃, the annealing time is 70 minutes, the annealing temperature after the second cold rolling is 770 ℃, the annealing time is 60 minutes, and the third cold rolling and the corresponding annealing treatment are not carried out.

Comparative example three

The step of putting the blank into a dehydrogenation furnace for dehydrogenation is reduced compared with the second comparative example, namely:

The kovar alloy foils prepared in examples one to five and comparative examples one to three were measured for hydrogen content (ppm), tensile strength (MPa), yield strength (MPa), elongation (%), hardness (HV), surface roughness (μm), thickness uniformity (μm) and performance parameter comparison, respectively, as follows.

And (3) measuring hydrogen content:

A LECORH-600 type hydrogen analyzer is adopted, 1g of sample is cut from the kovar alloy foil prepared in each example and comparative example, the sample is cut into small pieces by a cutting tool so as to ensure that the sample can completely enter a reaction furnace of the analyzer, the sample is placed into a clean and dry quartz boat, the hydrogen analyzer is calibrated by using a sample with standard hydrogen content (such as a kovar alloy standard sample with known hydrogen content), the standard sample is placed into an instrument according to the requirement of an instrument operation manual, the parameters of the instrument are measured, the measured value is adjusted to be consistent with the known hydrogen content of the standard sample, the boat with the sample is placed into a sample inlet of the hydrogen analyzer, the instrument is started, the sample is automatically sent into a high-temperature reaction furnace by the instrument, the hydrogen is released at high temperature along with carrier gas, the hydrogen content is recorded and calculated by the instrument, and the measurement result is displayed in units of ppm (parts per million).

Tensile and yield strength determination:

adopting I nstron5982 series electronic universal tester, according to the requirements of1 st part of metal material tensile test: room temperature test method of national standard GB/T228.1-2010, for the kovar alloy foil material, making into dumbbell-shaped test sample, the length of gauge length is 50mm, the width is 10mm (properly regulated according to the actual thickness of foil material), the thickness is the actual thickness of foil material, then polishing the surface of test sample by sand paper to remove oxide layer and defect, ensuring smooth surface, regulating the collet spacing of the test material tester to proper position to adapt to sample length, setting test speed to 3mm/min, starting force sensor and displacement sensor of test sample, and making zero clearing operation, ensuring accuracy of initial data, respectively clamping both ends of test sample in upper and lower chucks of test sample machine, ensuring that the test sample is clamped and perpendicular to collet axis, starting test sample, automatically recording tensile force and elongation of test sample, drawing stress-strain curve, when the test sample is broken, recording maximum tensile force value F _b, calculating to be sigma 3554/A, in which the yield stress is obviously equal to the standard stress of 2. _y＝F_y, when the test sample is broken, wherein the yield stress is obviously equal to the standard stress of the standard stress is 2% when the standard stress is found out that the standard stress is 2. _y＝F_y, the yield stress is applied to the standard stress of the standard stress, the standard is applied to the standard stress is 2, the calculation is performed by finding the corresponding force value on the stress-strain curve.

Elongation measurement:

And measuring the ratio of the elongation of the gauge length after the sample is broken to the original gauge length in the tensile test process by adopting I nstron5982 series of electronic universal testers, namely the elongation. That is, during the tensile test for measuring the tensile strength, the elongation of the gauge length of the test specimen is recorded at the same time, after the test specimen is broken, the broken test specimen is butted together, the total length L _f of the gauge length after the breaking is measured by using a gauge (such as a vernier caliper), and the calculation formula of the elongation delta is delta= (L _f-L₀)/L₀ x 100%, wherein L ₀ is the original gauge length of the test specimen (selected as 50 mm).

Hardness measurement:

cutting a kovar alloy foil into a 10mm multiplied by 10 mm-sized sample by adopting an MHV-1000Z automatic turret micro Vickers hardness tester, wherein the thickness is the actual thickness of the foil, polishing and polishing the surface of the sample to ensure the accuracy of hardness measurement, setting the test force of 0.4kgf (1 kgf=9.8N), setting the loading time and the holding time of the hardness tester to be 15s, holding time to be 15s, placing the sample on a workbench of the hardness tester, adjusting the focal length to enable the pressure head to be clearly aligned with the surface of the sample, starting the hardness tester, pressing the pressure head into the surface of the sample under the action of the test force, removing the test force after the test force is maintained, measuring the two diagonal lengths d ₁ and d ₂ of the indentation by using a microscope, calculating the Vickers hardness value HV to be HV= 1.8544F/d ², wherein F is the test force (N), d= (d ₁+d₂)/2 is the average length (mm) of the diagonal line of the indentation, calculating the average value, taking the average value at 8 different positions of the surface as the hardness value of the sample.

Surface roughness measurement:

a flat area is cut from the kovar alloy foil to be used as a measurement sample by adopting a Taylor-Hopkinson SurtronicS-128 type surface roughness meter, the area is 50mm multiplied by 50mm, and the surface of the sample is ensured to be clean and free of impurities such as dust, greasy dirt and the like so as not to influence the measurement result. The surface roughness measurement instrument is calibrated using a standard roughness template. The standard template is placed on a measurement table and a calibration operation is performed to match the instrument measurements with the known roughness values of the standard template. The sample is placed on the measuring table horizontally, and is well fixed, so that the sample is prevented from moving in the measuring process. The measuring probe is gently placed on the surface of the sample, and the measuring instrument is started. The probe performs a scanning measurement at a certain speed and travel on the sample surface. The instrument automatically records the measurement data and calculates the surface roughness parameters, and the surface roughness values of the foil are obtained by measuring the surface roughness values of the foil 5 times at different positions of the surface of the sample.

Thickness uniformity measurement:

The method comprises the steps of selecting a whole square kovar alloy foil with a side length of 100mm as a measuring object by using a German Mark MAHRMI L L IMARC model 1208 thickness gauge, ensuring that the foil is flat and has no folds and deformation, selecting a measuring point every 20mm on the square foil with the side length of 100mm, selecting 25 points in total, enabling a micrometer screw to be in vertical contact with the surface of the foil when the micrometer screw is used, lightly rotating a micro cylinder to enable the micrometer screw to be just in contact with the surface of the foil, reading a numerical value on the micrometer screw after hearing a click sound, recording the numerical value as the thickness value of the point, placing a measuring probe on the selected measuring point according to the operation instruction of an instrument when the film thickness gauge is used, automatically displaying the thickness value of the point by the instrument, and calculating the average value of the thickness values of all the measuring points Calculating the thickness t _i and the average value of each measuring pointDeviation of (2)Thickness uniformity is expressed in units of μm as maximum deviation value max (|Δt _i |), i.e. thickness uniformity = max (|Δt _i |), where i = 1, 2.

Comparative analysis was performed by the respective performance parameters determined in the above examples one to five and comparative examples one to three.

In terms of hydrogen content:

The hydrogen content of the first to fifth examples is in the range of 1.93-2.56ppm, the whole is in a lower level, the method is beneficial to strict control of links such as raw materials, smelting, pouring and the like in the preparation process, for example, argon protective atmosphere is adopted in smelting to prevent alloy oxidization and air suction, sufficient degassing treatment is carried out in pouring, for example, the second example is carried out in an environment with the vacuum degree of 30Pa for 12 minutes, then argon is introduced to carry out blowing stirring, the hydrogen content in the metal liquid is effectively reduced, the hydrogen content of the first and second examples is respectively 4.85ppm and 3.91ppm, which is obviously higher than that of the first example, the control of trace element S in the first comparative example is relatively loose (S=0.02% and is higher than that of 0.01% in the examples), the protective atmosphere and degassing measures in smelting and pouring are not perfect as in the examples, more hydrogen possibly enter the alloy, the process before the second comparative example is different from the first example in the degassing treatment, for example is not sufficient in the air suction treatment, the hydrogen content is 4.85ppm and 3.91ppm respectively, which is obviously higher than that of the alloy in the first example, and the most of the alloy is not dehydrated, and the hydrogen content in the second example is greatly reduced, which is the hydrogen content of the alloy is not affected by the dehydrogenation foil, and the hydrogen content is greatly reduced in the most serious conditions than that of the dehydrogenating method has been shown in the alloy.

In terms of mechanical properties (tensile strength, yield strength, elongation):

Examples one to five exhibited better performance in terms of tensile strength, yield strength and elongation; the tensile strength is 520-550MPa, the yield strength is 480-505MPa, and the elongation is 28-35%; the method is characterized in that a reasonable forging process, such as a forging mode with multiple passes and small deformation (the deformation of each pass is controlled between 12% and 18%) is adopted in the preparation process, so that the structure is gradually refined, and the mechanical property of the material is improved; the method has the advantages of uniform control of furnace atmosphere in the heating process, prevention of local oxidation or decarburization of steel ingots, contribution to improvement of strength and toughness of materials, 460MPa of tensile strength, 420MPa of yield strength, 20% of elongation, 485MPa of tensile strength, 440MPa of yield strength, 23% of elongation, obvious poorer mechanical properties compared with the embodiment group, and the like mainly because of defects in raw material composition control, smelting and casting process, forging process and the like, for example, the internal surface treatment of a mold in the first comparative example is rough, no special release agent is used, the casting mode is upward injection and no heat preservation measures are adopted, the heating rate is high, the number of passes is small, the deformation amount is large, the equipment striking force and frequency are unstable and the like in the forging process, the factors lead to non-uniform material structure and more defects, so that the mechanical properties are reduced, the mechanical properties of the third comparative example are worst, the tensile strength is only 450MPa, the yield strength is 410MPa, the elongation is 18%, besides the problems similar to the first comparative example and the second comparative example are solved, the hydrogen content in the dehydrogenation treatment step leads to high hydrogen content in the material to form the brittle materials in the internal materials, resulting in a substantial decrease in tensile strength, yield strength and elongation.

In terms of hardness:

the hardness values of the first to fifth examples are in a reasonable range from 145 to 152HV, the hardness values are stable and are in a reasonable range because the fine control from raw material selection to each process step in the whole preparation process ensures the uniformity and compactness of the tissue structure of the material, so that the hardness performance is good, for example, the mechanical polishing and chemical cleaning combined method is adopted for surface cleaning in the blank treatment process, the preparation is carried out for the subsequent flaw detection and processing procedures, the influence of the surface defects on the hardness measurement is reduced, meanwhile, the reasonable heat treatment process (such as multiple cold rolling and annealing treatments) is also helpful for adjusting the hardness of the material, the hardness of the first and second comparative examples are respectively 130HV and 135HV and are lower than that of the first example, the defects in the process control such as unstable smelting temperature, unreasonable forging process and the like in the comparative example possibly cause the tissue structure of the material to be uneven, the hardness is influenced, the hardness of the third comparative example is 125HV, the lowest in all groups is the lowest, the problem that the first and second comparative example is not only existed, the high hydrogen content has the negative effect on the hardness of the material, and the lattice structure of the material is reduced.

In terms of surface roughness:

the surface roughness of the first to fifth examples is 0.052-0.085 mu m, the surface quality is better, the surface roughness Ra is controlled in a lower range by focusing on the use of mold surface treatment and release agent in the preparation process, such as fine polishing and polishing treatment of the inner surface of the mold, and meanwhile, the high-temperature resistant release agent is smeared on the inner wall of the mold, thereby reducing the adhesion between steel ingots and the mold, reducing the possibility of surface defects, further improving the surface roughness of the material in the subsequent processing process, such as polishing treatment after cold rolling, and the like, the surface roughness of the first comparative example is 0.157 mu m, the second comparative example is 0.129 mu m, the third comparative example is 0.136 mu m, the control of links such as mold preparation, casting process and subsequent surface treatment in the comparative example is not as strict as in the examples, for example, the inner surface polishing and polishing treatment of the mold in the first comparative example is rough, the surface quality of the steel ingots is directly influenced, further, the surface roughness of the foil after the subsequent processing is higher, the second comparative example and the third comparative example has similar problems in that the surface roughness and the similar quality to the second comparative example can not influence the surface roughness in the similar process, and the surface roughness is greatly influenced by the addition of the surface roughness and the similar surface quality.

In terms of thickness uniformity:

The thickness uniformity of the first to fifth embodiments is better, the deviation is between +/-1.5 and +/-3 mu m, in the rolling process, the uniform deformation of the material in the thickness direction is ensured by precisely controlling the hot rolling and cold rolling process parameters such as hot rolling temperature, time, cold rolling times, annealing treatment and the like, meanwhile, the dimensional accuracy and the tissue uniformity of the blank are effectively controlled in the blank treatment and forging process, a good basis is provided for the subsequent rolling, so that the thickness uniformity of the kovar alloy foil is ensured, the thickness uniformity deviation of the first comparison is +/-6 mu m, the second comparison is +/-5 mu m, the third comparison is +/-6.5 mu m, which is obviously inferior to the embodiment group, the defect of the first comparison in the rolling process and the previous blank treatment process causes the poor thickness uniformity, for example, the first comparison has the conditions that the control of the forging process is not strict, the die has no heat preservation measures and the like, the internal structure of the blank is uneven, the thickness deviation is easy to occur in the rolling process, the second comparison and the third comparison has similar problems, and the uniformity of the thickness uniformity of the third comparison is difficult to ensure due to the defect of the uniformity of the dehydrogenation material in the rolling process.

It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.

The embodiments of the present invention are described in a progressive manner, and the same and similar parts of the embodiments are all referred to each other, and each embodiment is mainly described in the differences from the other embodiments. In particular, for system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, as relevant to see a section of the description of method embodiments.

It will be appreciated by persons skilled in the art that the foregoing discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosure is limited to these examples, that combinations of features in the above embodiments or in different embodiments may also be implemented in any order and that many other variations of the different aspects of one or more embodiments of the invention as described above exist within the spirit of the disclosure, which are not provided in detail for clarity.

While the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of those embodiments will be apparent to those skilled in the art in light of the foregoing description.

The present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the present invention. Accordingly, any omissions, modifications, equivalents, improvements, and the like, which are within the spirit and principles of the one or more embodiments of the invention, are intended to be included within the scope of the present disclosure.

Claims

1. A method for preparing a kovar alloy foil, characterized in that the preparation method comprises:

S1: placing a kovar alloy raw material in a smelting furnace for smelting, and pouring the smelted metal liquid into a target mold to form a steel ingot, wherein the mass percentage of the trace element S component in the kovar alloy raw material is controlled to be: S≤0.01%, the smelting temperature is 1600-1700°C, and the smelting is carried out under an argon protective atmosphere. Before pouring, the metal liquid is kept in an environment with a vacuum degree of 10-50Pa for 10-15 minutes for preliminary vacuum treatment, and then argon is introduced into the metal liquid for blowing and stirring, the argon flow rate is controlled at 5-10L/min, and the stirring time is 5-8 minutes; the pouring adopts a bottom pouring method, the pouring temperature is 1550-1600°C, and the pouring speed is 2-5kg/s; the target mold is subjected to heat preservation treatment during the pouring process;

S2: heating the steel ingot prepared in step S1, first preheating the steel ingot to 550-600°C at a heating rate of 60-80°C/h, keeping the temperature for 2-3 hours, and then heating the steel ingot to a forging temperature range of 1150-1200°C at a rate of 100-120°C/h, and controlling the oxygen content in the furnace to be below 0.05% through a furnace gas circulation device during the heating process; gradually forging the steel ingot into the desired blank shape by a multi-pass small deformation forging method, and controlling the deformation of each pass to be between 12% and 18%;

S3: Cooling the blank forged in step S2 and then cleaning its surface, wherein the surface cleaning is performed by combining mechanical grinding and chemical cleaning;

S4: placing the blank after surface cleaning in step S3 in a dehydrogenation furnace, and filling the dehydrogenation furnace with argon gas; allowing the dehydrogenation furnace to heat and dehydrogenate the alloy, the dehydrogenation temperature is 1430-1480° C., and the dehydrogenation time is 2.5-3.5 hours; after the dehydrogenation is completed, the dehydrogenation furnace is turned off and the alloy is naturally cooled to room temperature in the dehydrogenation furnace;

S5: hot rolling the alloy after the dehydrogenation treatment in step S4, the hot rolling treatment temperature is 410-430°C, and the hot rolling time is 70-80 minutes; the hot rolled alloy is subjected to multiple cold rolling, cleaning and annealing steps to a kovar alloy foil of target thickness, wherein the annealing temperature after the first cold rolling is 470-480°C, the annealing time is 65-75 minutes, and the cleaning is carried out with dilute hydrochloric acid.

2. The method for preparing the Kovar alloy foil according to claim 1 is characterized in that the components of the Kovar alloy raw material include, by mass percentage: C≤0.015%, P≤0.01%, S≤0.01%, Mn: 0.35-0.45%, Si≤0.20%, Cu≤0.10%, Cr≤0.10%, Mo≤0.10%, Ni: 28.8%-29.2%, Co: 17.0-17.3%, Zr: 0.1-0.2%, Nb: 0.05-0.15%, and the balance is Fe.

3. The method for preparing the Kovar alloy foil according to claim 1, characterized in that step S3 specifically comprises:

Place the blank in a holding furnace and slowly cool it down with the furnace at a cooling rate of 60-80℃/h;

The blank is polished by mechanical polishing, the polishing pressure is 0.2-0.4MPa, and the polishing speed is 10-15m/min;

The blank is placed in a chemical cleaning tank and cleaned with a cleaning solution for 15-25 minutes. During the cleaning process, the cleaning solution is stirred at a stirring speed of 30-50 r/min.

After cleaning, the blank is rinsed with clean water at a flushing pressure of 0.1-0.3MPa and a flushing time of 3-5 minutes.

4. The method for preparing the Kovar alloy foil according to claim 1, characterized in that step S4 further comprises:

The alloy after dehydrogenation treatment is ground by a grinding machine, wherein the grinding direction remains unchanged;

The polishing machine is used to polish the alloy after grinding.

5. The method for preparing the Kovar alloy foil according to claim 1, characterized in that the hot-rolled alloy is subjected to three steps of cold rolling, cleaning and annealing, specifically:

The hot-rolled alloy is sent to a rolling mill for the first rolling, and the rolled alloy is washed with dilute hydrochloric acid and then annealed for the first time;

The alloy after the first annealing is sent to a rolling mill for a second rolling, and the rolled alloy is washed with dilute hydrochloric acid and then annealed for a second time, wherein the annealing temperature is 780-790°C and the annealing time is 60-70 minutes;

The alloy after the second annealing is sent to the rolling mill for the third rolling. The rolled alloy is washed with dilute hydrochloric acid and then annealed for the third time to obtain a Kovar alloy foil of target thickness, wherein the annealing temperature is 530-540°C and the annealing time is 60-70 minutes.

6. The method for preparing the Kovar alloy foil according to claim 5, characterized in that step S5 further comprises:

The Kovar alloy foil after the third annealing is cleaned with an ultrasonic cleaner for 10-15 minutes and then polished.