Production process for preventing grain growth of titanium-steel clad plate

Abstract

The present application belongs to the technical field of titanium steel composite plate, in particular, relates to a production process for preventing grain growth of titanium steel composite plate, comprising roughening the lower side of the titanium plate and the upper side of the steel plate by adopting sand blasting process; spraying additives on the upper side of the steel plate and the lower side of the titanium plate, the additives comprising boron powder and a binding agent, laying graphite foil on the upper side of the steel plate after spraying the additives, stacking the titanium plate after spraying the additives on the steel plate, clamping the graphite foil between the upper side of the steel plate and the lower side of the titanium plate to make a composite plate blank; sealing the edge of the composite plate blank with sealing material; heating the composite plate blank in a heating furnace, rolling and cooling the heated composite plate blank, straightening the composite plate blank in a straightening machine, and cutting the edges of the straightened composite plate blank to obtain a titanium steel composite plate, the production process avoids excessive growth of the grain at the bonding surface of the titanium steel composite plate, and improves the bonding strength and shear strength of the titanium steel composite plate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium steel composite plate, and particularly relates to a production process for preventing grain growth of a titanium steel composite plate. BACKGROUND

[0002] In modern industrial production, titanium steel composite plates have excellent comprehensive performance, such as the corrosion resistance of titanium materials and the high strength of steel materials. As one of the commonly used methods for producing titanium steel composite plates, the hot rolling process has the advantages of high production efficiency and relatively low cost. For example, the invention disclosed in the invention patent with the patent number CN102794299B discloses a rolling method for titanium steel composite plates, which comprises the following steps: selecting a titanium steel composite plate with a titanium plate as the upper layer and a steel plate as the lower layer, cleaning the outer surface of the selected titanium steel composite plate, coating a layer of anti-oxidation paint on the surface of the titanium plate as an anti-oxidation layer to obtain a pretreated titanium steel composite plate, heating and homogenizing the pretreated titanium steel composite plate, and rolling the homogenized titanium steel composite plate on a hot rolling mill while simultaneously descaling and cooling the titanium steel composite plate by using high-pressure water.

[0003] However, in the production process of hot-rolled titanium steel composite plates, the interface problem has always been a key factor restricting the performance improvement and wide application of the titanium steel composite plates. In particular, the grain growth phenomenon easily occurs at the interface, which brings many adverse effects. The abnormal growth of grains at the interface will lead to a decrease in the interface bonding strength, and in the subsequent use process, the interface of the composite plate is prone to delamination, cracking and other defects, which seriously affects the reliability and service life of the product. Moreover, the uneven grain structure also causes the mechanical properties and corrosion resistance of the composite plate to be unevenly distributed, which reduces the overall performance stability of the material. In addition, due to the difficulty in effectively controlling the grain growth problem, the product quality of the hot-rolled titanium steel composite plates fluctuates greatly, which increases the waste rate in the production process and increases the production cost. This is undoubtedly a problem that needs to be solved urgently for modern industry that pursues efficient and high-quality production. Therefore, how to inhibit the grain growth at the interface of the hot-rolled titanium steel composite plate and improve the interface quality and the comprehensive performance of the composite plate has become a research hotspot and a key technical problem in the field, and therefore, a new production process for preventing grain growth of a titanium steel composite plate is urgently needed to inhibit the grain coarsening at the interface of the titanium steel composite plate and improve the comprehensive performance through interface modification, rolling process synergistic regulation and other means. SUMMARY

[0004] In view of the above problems, the application provides a production process for preventing grain growth of a titanium steel composite plate, which solves the problems that the abnormal growth of grains at the interface of the titanium steel composite plate in the existing hot-rolled titanium steel composite plate technology leads to a decrease in the interface bonding strength, and the grain growth problem is difficult to effectively control, which causes the product quality of the titanium steel composite plate to fluctuate greatly.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is as follows: A production process for preventing grain growth of titanium-steel composite plate, comprising the following steps:

[0006] Step one, selecting titanium plate with thickness of 0.5-5mm as upper layer and steel plate with thickness of 3-20mm as lower layer;

[0007] Step two, placing the titanium plate and the steel plate in step one into a cleaning tank containing degreasing agent for cleaning, and then cleaning by using high-pressure water gun;

[0008] Step three, roughening the lower side of the titanium plate and the upper side of the steel plate by using sand blasting process;

[0009] Step four, spraying additive on the upper side of the steel plate and the lower side of the titanium plate, wherein the additive comprises boron powder and binder;

[0010] Step five, laying graphite foil on the upper side of the steel plate after spraying additive in step four, and stacking the titanium plate after spraying additive in step four on the steel plate, so as to make the upper side of the steel plate and the lower side of the titanium plate sandwich the graphite foil to form a composite plate blank;

[0011] Step six, sealing the edge part of the composite plate blank by using sealing material;

[0012] Step seven, heating the composite plate blank by using heating furnace, and the heating temperature of the composite plate blank is 700-950℃;

[0013] Step eight, rolling the heated composite plate blank, and the rolling pass is at least three, the first rolling pass reduction is 10%-20%, the reduction of subsequent passes is gradually reduced, the reduction of the second last pass is 7%-10%, and the reduction of the last pass is 5%-7%, the first rolling speed is 0.5-1m / s, the rolling speed of subsequent passes is gradually increased, and the highest rolling speed is less than 2m / s;

[0014] Step nine, cooling the rolled composite plate blank, straightening the composite plate blank by using straightening machine, and obtaining titanium-steel composite plate by edge cutting treatment of the straightened composite plate blank.

[0015] Further, the roughness of the upper side of the steel plate and the lower side of the titanium plate in the roughening treatment in step three is 6.3-25μm.

[0016] Further, the addition amount of boron powder in the additive is 0.01%-0.1% of the total mass of the titanium plate and the steel plate.

[0017] Further, the binder is nickel-based binder.

[0018] Further, the mass ratio of the boron powder to the nickel-based binder is 1:5.

[0019] Further, the graphite foil in the step five has a purity of greater than 99%, and a thickness of 0.1-0.3 mm.

[0020] Further, the sealing material adopts a ceramic fiber sealing belt.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] After the bonding surface of the titanium plate and the steel plate is cleaned and sandblasted, a protective layer is formed on the bonding surface in the form of a sprayed additive, so as to prevent the bonding strength from being reduced due to oxidation of the bonding surface of the titanium plate and the steel plate.

[0023] Meanwhile, the graphite foil with a purity of greater than 99% and a thickness of 0.1-0.3 mm is laid between the steel plate and the titanium plate, so as to prevent titanium and steel from directly contacting and excessively reacting at high temperature, and to play a buffering and lubricating role in the rolling process, so as to facilitate the titanium plate and the steel plate to be better combined together.

[0024] In addition, during the heating process, the nickel-based binder can have a certain degree of diffusion reaction with titanium and steel. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] A production process for preventing grain growth of a titanium-steel composite plate includes the following steps:

[0027] Step one, a titanium plate with a thickness of 0.5-5 mm is selected, and the titanium plate can be one of TA1, TA2, TC4, TC6 and TC10. Step two, a steel plate with a thickness of 3-20 mm is selected, and the steel plate can be one of Q235, Q345, 302, 304 and 304L.

[0028] Step two, the titanium plate and steel plate in step one are put into a cleaning tank containing degreasing agent, the temperature of the degreasing agent in the cleaning tank is controlled at 40-60℃, the soaking time is 15-30 minutes, then high-pressure water gun is used for cleaning, the water pressure is controlled at 5-10Mpa.

[0029] Step three, the lower side of the titanium plate and the upper side of the steel plate are roughened by sandblasting process, the corundum sand with particle size of 40-60 mesh is selected for sandblasting, the roughness of the upper side of the roughened steel plate and the upper side of the titanium plate is 6.3-25μm, the treated titanium plate and steel plate are transferred to a clean environment.

[0030] Step four, an additive is sprayed on the upper side of the steel plate and the lower side of the titanium plate, a protective layer is formed by the sprayed additive to prevent the combination of the titanium plate and the steel plate from being oxidized to reduce the bonding strength, the additive includes boron powder and a binder, the binder is preferably a nickel-based binder, during the heating process, the nickel-based binder can have a certain degree of diffusion reaction with titanium and steel, nickel atoms will diffuse into the matrix of titanium and steel, and part of the elements in titanium and steel will also diffuse into the nickel-based binder, this diffusion will form a gradually transitional area at the interface, thereby forming a metallurgical bonding effect, thereby increasing the bonding surface strength, the mass ratio of the boron powder to the nickel-based binder is 1:5, the additive amount of the boron powder in the additive is 0.01%-0.1% of the total mass of the titanium plate and the steel plate, the binder is attached to the surface of the roughened steel plate and titanium plate by cold spraying.

[0031] Step five, the upper side of the steel plate after spraying the additive in step four is laid with graphite foil, first, the graphite foil is subjected to appearance inspection to ensure that the surface is flat, free of wrinkles, damage and obvious impurity particles.

[0032] Check if the thickness of the graphite foil meets the requirements, the thickness should be between 0.1-0.3mm, use a micrometer to measure multiple points on the graphite foil, at least 9 points according to a 3x3 grid distribution per square meter, ensure that the thickness deviation is within ±0.02mm, cut the graphite foil to a slightly larger size than the titanium plate and steel plate, this ensures that the graphite foil can completely cover the bonding surface of the titanium plate and steel plate, and has a certain margin for subsequent adjustment, starting from the center of the graphite foil, use a soft rubber scraper or a special smoothing tool to gently smooth the graphite foil towards the edge, making the graphite foil tightly adhere to the surface of the titanium plate, during the smoothing process, pay attention to keep the angle of the scraper or tool with the surface of the graphite foil at 30°-45°, and apply uniform pressure, the pressure is controlled at 0.1-0.2MPa, to avoid scratching the graphite foil or causing local deformation of the graphite foil, stack the titanium plate sprayed with additive in step four on the steel plate, ensure that the steel plate is accurately stacked, the deviation is controlled within ±0.5mm, the upper side of the steel plate and the lower side of the titanium plate sandwich the graphite foil, cut off the excess graphite foil on the edges of the steel plate and titanium plate to make a composite plate blank, under the high temperature and high pressure conditions of heating and rolling, titanium atoms and iron atoms have enough energy to diffuse, through the thermal motion of atoms, the activity of titanium atoms and iron atoms is enhanced, they can overcome a certain resistance and realize mutual approach and diffusion, thereby forming a certain degree of metallurgical bonding at the interface, the graphite foil mainly slows down the reaction speed between titanium and steel, preventing them from excessive bonding at high temperature, rather than completely stopping the reaction, it provides a relatively controllable environment for atomic diffusion, making the composite process more stable and uniform, at the same time, because the graphite foil is a brittle material, it is crushed during rolling, forming a uniform bonding area after each rolling pass, the lubricating effect of the graphite foil also helps the titanium plate and steel plate to better adhere during rolling, increasing the opportunity for atomic interaction.

[0033] Step six, seal the edge part of the composite plate blank with sealing material, the sealing material uses ceramic fiber sealing tape, which seals the edge part of the composite plate blank through multi-layer winding.

[0034] Step seven, heat the composite plate blank in a heating furnace, the heating furnace can use a gas radiation tube heating furnace or an electric heating furnace. After placing the blank in the heating furnace, slowly heat it to 700-950℃ at a heating rate of 5-15℃ / min. During the heating process, the temperature control system in the furnace monitors and adjusts the temperature of each area in the furnace in real time, ensuring that the blank is heated uniformly, and the temperature deviation is controlled within ±10℃. During the heating process, appropriate protective gas such as nitrogen or argon is introduced, the flow rate of the protective gas is controlled at 5-10m³ / h, the furnace is kept in a slightly positive pressure state, the entry of oxygen is reduced, the risk of oxidation is reduced, and the abnormal growth of grains is inhibited.

[0035] Step eight, the composite plate blank after heating is rolled, the rolling pass is at least three, the first rolling pass reduction is 10%-20%, the subsequent pass reduction is gradually reduced, the second last pass reduction is 7%-10%, the last pass reduction is 5%-7%, the first rolling speed is 0.5-1m / s, the subsequent rolling pass rolling speed is gradually increased, the highest rolling speed is less than 2m / s, in order to prevent the blank from heating during rolling, the spray cooling method can be used, the water mist is uniformly sprayed on the surface of the composite plate, the water mist pressure is controlled at 0.2-0.4MPa, the cooling time and the cooling water amount are accurately controlled, so that the temperature of the composite plate is kept in the appropriate rolling temperature range, and the grain growth is effectively inhibited.

[0036] In the process of heating and rolling, due to the existence of boron powder in the bonding interface of the composite plate blank, boron atoms have a small atomic radius, and in the process of heating and rolling of the titanium steel composite plate to 700-950℃, the boron atoms will dissolve in the matrix and tend to segregate at the grain boundary. The grain boundary is a region where the atomic arrangement is irregular in the crystal, and has a high energy. The segregation of boron atoms at the grain boundary is equivalent to setting many small obstacles on the grain boundary. When the grain attempts to migrate through the grain boundary to achieve growth, these segregated boron atoms will hinder the movement of the grain boundary, making the migration of the grain boundary difficult, thereby effectively inhibiting the growth of the grain, so that the grain needs to overcome a larger energy barrier during growth, thereby limiting the growth rate and size of the grain. The segregation of boron atoms at the grain boundary also changes the energy state and interface characteristics of the grain boundary. On the other hand, the presence of boron atoms reduces the surface energy of the grain boundary. The grain boundary energy is one of the important factors driving the growth of the grain. The reduction of the grain boundary energy means that the driving force for the growth of the grain is reduced, thereby slowing down the growth rate of the grain. At the same time, the segregation of boron atoms changes the electronic structure and atomic arrangement of the grain boundary, increasing the stability of the grain boundary, which further hinders the migration of the grain boundary, making it difficult for the grain to grow by moving through the grain boundary. In addition, boron atoms may also form chemical bonds or special atomic clusters with other atoms near the grain boundary, which will also affect the properties of the grain boundary, further enhancing the inhibition of grain growth.

[0037] Step nine, the rolled composite plate blank is cooled. For the composite plate with a total thickness of less than 10mm, air cooling can be used to cool in the natural environment, and the cooling speed is controlled at 10-20℃ / min. For the composite plate with a total thickness of more than 10mm, air cooling is used, and the cooling speed is controlled at 15-30℃ / min by a fan. The composite plate blank is straightened by a straightening machine, and the straightened composite plate blank is edge trimmed to obtain a titanium steel composite plate.

[0038] The following is compared by three groups of examples and one group of comparative examples. The experimental data of examples and comparative examples are obtained by GB / T8547-2019 "Titanium-steel composite plate" and GB / T6396 "Test method for mechanical and technological properties of composite steel plate". Example one

[0039] Material selection: TA2 titanium plate with a thickness of 1mm is selected as the upper layer, and 302 steel plate with a thickness of 5mm is selected as the lower layer.

[0040] Additive spraying: the mass ratio of boron powder to nickel-based binder is 1:5, and the boron powder addition amount is 0.01% of the total mass of titanium plate and steel plate.

[0041] Composite plate blank heating: put into the electric heating furnace, heat up to 800℃ at a speed of 10℃ / min, and pass in appropriate amount of argon protection.

[0042] Rolling: four passes are carried out, the first pass reduction rate is 12%, the speed is 0.6m / s; the second pass reduction rate is 10%, the speed is 1.1m / s; the third pass reduction rate is 8%, the speed is 1.3m / s; the fourth pass reduction rate is 6%, the speed is 1.6m / s.

[0043] Example one experimental data:

[0044] Bonding strength: 155MPa, which meets the requirement of GB / T8547-2019 that the bonding strength is greater than or equal to 140MPa.

[0045] Shear strength: 183MPa, which meets the relevant test of GB / T6396 standard.

[0046] Tensile strength: it meets the corresponding standard requirement of 302 steel composite plate, and there is no obvious deformation or separation at the bonding position of titanium layer and steel layer, which meets the relevant test of GB / T6396 standard.

[0047] Bending test: when the bending radius is 2 times the plate thickness, the sample bending part has no cracks, delamination and other defects, which meets the GB / T8547-2019 standard. Example two

[0048] Material selection: TC6 titanium plate with a thickness of 3mm is selected as the upper layer, and Q345 steel plate with a thickness of 12mm is selected as the lower layer.

[0049] Additive spraying: the boron powder addition amount is 0.05% of the total mass, and the mass ratio of boron powder to nickel-based binder is still 1:5.

[0050] Composite plate blank heating: use gas radiation tube heating furnace, heat up to 900℃ at a speed of 12℃ / min, and pass in nitrogen protection.

[0051] Rolling: Five passes were carried out, the first pass reduction rate was 16%, the speed was 0.8 m / s; the second pass reduction rate was 13%, the speed was 1.2 m / s; the third pass reduction rate was 10%, the speed was 1.4 m / s; the fourth pass reduction rate was 8%, the speed was 1.5 m / s; the fifth pass reduction rate was 6%, the speed was 1.7 m / s.

[0052] Example two experimental data:

[0053] Bonding strength: 168 MPa, which meets the requirement of GB / T8547-2019 that the bonding strength is greater than or equal to 140 MPa.

[0054] Shear strength: 193 MPa, which meets the relevant test of GB / T6396 standard.

[0055] Tensile strength: It meets the standard requirement of Q345 steel composite plate, the titanium steel is well bonded, and it meets the relevant test of GB / T6396 standard.

[0056] Bending test: When the bending radius is 2 times the plate thickness, the sample has no cracks, delamination and other defects, which meets the standard of GB / T8547-2019. Example three

[0057] Material selection: TC10 titanium plate with a thickness of 4 mm was selected as the upper layer, and 304L steel plate with a thickness of 18 mm was selected as the lower layer.

[0058] Additive spraying: The addition amount of boron powder was 0.1% of the total mass, and the mass ratio of boron powder to nickel-based binder was 1:5.

[0059] Composite plate blank heating: Put it into an electric heating furnace, heat it to 920℃ at a speed of 15℃ / min, and protect it by passing in argon.

[0060] Rolling: Four passes were carried out, the first pass reduction rate was 18%, the speed was 0.9 m / s; the second pass reduction rate was 14%, the speed was 1.3 m / s; the third pass reduction rate was 11%, the speed was 1.5 m / s; the fourth pass reduction rate was 7%, the speed was 1.8 m / s.

[0061] Example three experimental data:

[0062] Bonding strength: 162 MPa, which meets the requirement of GB / T8547-2019 that the bonding strength is greater than or equal to 140 MPa.

[0063] Shear strength: 188 MPa, which meets the relevant test of GB / T6396 standard.

[0064] Tensile strength: It meets the standard of 304L steel composite plate, the titanium steel interface is stable, and it meets the relevant test of GB / T6396 standard.

[0065] Bending test: when the bending radius is 2 times the thickness of the plate, the sample has no cracks, delamination and other defects, meeting the GB / T8547-2019 standard.

[0066] Comparative example:

[0067] Material selection: TA2 titanium plate with a thickness of 1 mm is selected as the upper layer, and 302 steel plate with a thickness of 5 mm is selected as the lower layer.

[0068] Additive spraying: no additive containing boron powder is sprayed, and no nickel-based binder and graphite foil are used.

[0069] Rolling: the rolling pass and reduction rate speed are the same as those of example 1.

[0070] Experimental data:

[0071] Bonding strength: 125 MPa, lower than the requirement of 140 MPa in GB / T8547-2019.

[0072] Shear strength: 150 MPa, lower than the data of example.

[0073] Tensile strength: although it meets the basic requirements of 302 steel, there are obvious signs of deformation at the titanium-steel bonding site, which does not meet the requirements of GB / T6396 standard for good bonding.

[0074] Bending test: when the bending radius is 2 times the thickness of the plate, the sample has obvious cracks and delamination, which does not meet the GB / T8547-2019 standard.

[0075] From the experimental data of example one, example two and example three, it can be seen that the titanium-steel composite plate obtained by using the process for preventing and controlling the grain growth of titanium-steel composite plate in the present application has higher bonding strength, shear strength and other properties than the national standard data when various types and models of titanium plates and steel plates are sprayed with boron-containing powder and nickel-based binder and graphite foil.

[0076] Comparing example one with example two and example three, it can be seen from the experimental data that appropriately increasing the amount of boron powder within the range of the boron powder addition value or using multi-pass rolling can effectively improve the bonding strength and shear strength.

[0077] Comparing example one, example two, example three and comparative example one, it can be seen that the process for preventing and controlling the grain growth of titanium-steel composite plate in the present application can effectively improve the structural strength and shear strength, and is better than the traditional titanium-steel composite plate rolling process in terms of tensile strength and bending test.

[0078] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalent features, by those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A production process for preventing grain growth in titanium-steel composite plates, characterized in that, Includes the following steps: Step 1: Select a titanium plate with an upper layer thickness of 0.5-5mm and a steel plate with a lower layer thickness of 3-20mm. Step 2: Place the titanium plate and steel plate from Step 1 into a cleaning tank containing a degreasing agent for cleaning, and then clean them with a high-pressure water gun. Step 3: Roughen the lower side of the titanium plate and the upper side of the steel plate using a sandblasting process; Step 4: Spray an additive onto the upper side of the steel plate and the lower side of the titanium plate. The additive includes boron powder and a binder. Step 5: Lay graphite foil on the upper side of the steel plate after the additive was sprayed in Step 4, and stack the titanium plate after the additive was sprayed in Step 4 on the steel plate, so that the upper side of the steel plate and the lower side of the titanium plate hold the graphite foil to form a composite plate blank. Step 6: Seal the edges of the composite board blank using a sealing material; Step 7: Heating the composite board blank in a heating furnace at a temperature of 700℃-950℃; Step 8: Roll the heated composite plate blank. The rolling passes should be at least three. The first rolling pass has a reduction rate of 10%-20%, and the reduction rate of subsequent rolling passes gradually decreases. The second to last rolling pass has a reduction rate of 7%-10%, and the last rolling pass has a reduction rate of 5%-7%. The rolling speed of the first rolling pass is 0.5-1m / s, and the rolling speed of subsequent rolling passes gradually increases, with the maximum rolling speed being less than 2m / s. Step 9: Cool the rolled composite plate blank, straighten the composite plate blank using a straightening machine, and trim the edges of the straightened composite plate blank to obtain the titanium-steel composite plate.

2. The production process for preventing grain growth in titanium-steel composite plates according to claim 1, characterized in that: In step three, the roughness of the upper surface of the steel plate and the lower surface of the titanium plate is 6.3-25 μm.

3. The production process for preventing grain growth in titanium-steel composite plates according to claim 1, characterized in that: The amount of boron powder added in the additive is 0.01%-0.1% of the total mass of the titanium plate and the steel plate.

4. The production process for preventing grain growth in titanium-steel composite plates according to claim 1, characterized in that: The binder is a nickel-based binder.

5. The production process for preventing grain growth in titanium-steel composite plates according to claim 4, characterized in that: The mass ratio of boron powder to nickel-based binder is 1:

5.

6. The production process for preventing grain growth in titanium-steel composite plates according to claim 1, characterized in that: In step five, the graphite foil has a purity greater than 99% and a thickness of 0.1–0.3 mm.

7. The production process for preventing grain growth in titanium-steel composite plates according to claim 1, characterized in that: The sealing material is ceramic fiber sealing tape.