A production method of a cold-rolled titanium steel clad plate coil

Abstract

The application provides a production method of a cold-rolled titanium steel composite plate roll, and industrial production is realized through the following steps: S1, selecting a titanium steel composite plate roll as a cold-rolled raw material; S2, removing a titanium layer at the head and tail of the raw material to expose a steel base material, and welding the steel base material with a stainless steel leading tape; S3, using a continuous annealing furnace to anneal the composite plate roll after welding in S2, and then performing shot blasting and pickling after the annealing; S4, cold rolling: using a reversible reciprocating mill to roll, using a constant rolling force mode to cold roll, and controlling the cumulative deformation to be 50%-75% and single pass to be less than or equal to 15%; S5, degreasing the composite plate roll after the cold rolling; S6, multi-step vacuum annealing the composite plate roll after the degreasing; S7, skin passing the composite plate roll after the vacuum annealing; S8, tension leveling the composite plate roll after the skin passing, and a cold-rolled titanium steel composite plate roll is prepared. The application does not need a large reduction in the first pass, and does not need a special powerful rolling mill, and can realize continuous production of the cold-rolled titanium steel composite plate roll with good performance by using a conventional production line.

Description

Technical Field

[0001] This invention relates to the field of titanium-steel composite plate manufacturing technology, and more particularly to a method for producing cold-rolled titanium-steel composite plate coils. Background Technology

[0002] Titanium-steel composite plates, due to their combination of the excellent properties of titanium and steel and significant cost advantages, have gradually replaced some hot-rolled pure titanium sheets in various fields. With continuous advancements in manufacturing technology, more and more applications are demanding cold-rolled titanium-steel composite plates, hoping they can replace pure cold-rolled titanium sheets. However, to date, no reports have been found regarding cold-rolled titanium-steel composite plates.

[0003] The traditional bimetallic cold-rolled composite process is a three-step production process: surface treatment + cold rolling composite + diffusion annealing. This involves directly rolling two surface-treated metals or alloys into a rolling mill at low or room temperature, followed by diffusion annealing in a furnace to produce rolled bimetallic composite sheets of the desired thickness. A critical deformation amount exists during the first rolling pass; below this amount, effective composite bonding cannot be achieved. In actual production, this amount typically needs to reach 60%–70%, or even higher, thus placing high demands on the rolling mill. Currently, this method is mainly used in aluminum-based multilayer metal composites, producing copper-aluminum, steel-aluminum, and nickel-iron alloy-aluminum bimetallic composite sheets and strips, but it is not suitable for titanium-steel composite sheets.

[0004] Previously, scholars had conducted research on cold-rolled titanium-steel composite plates, proposing a "cold-hot rolling composite method" for their preparation. This method involves first pre-compositing the titanium / steel billet through cold rolling to prevent oxidation at the titanium / steel interface during subsequent hot rolling. Then, induction heating and single-pass hot rolling are used to improve the interfacial bonding quality, thus producing the titanium / steel composite plate. The raw materials used were TA2 0.2mm thick and Q235 steel 4.4mm thick, first cold-rolled to 2.5mm, and then hot-rolled to a finished thickness of 1.2mm. This method is essentially a hot rolling method; the cold rolling step in the above process is equivalent to the vacuum assembly stage of hot rolling. However, this method can only produce narrow strips with widths below 300mm, and stable production is not feasible. Summary of the Invention

[0005] To address the technological gap in the industrial production of cold-rolled titanium-steel composite sheets and coils, this invention provides a method for producing cold-rolled titanium-steel composite sheets and coils.

[0006] The technical means employed in this invention are as follows: A method for producing cold-rolled titanium-steel composite sheet coils includes the following steps: S1. Raw Material Preparation: Titanium-steel composite sheet coils were selected as the raw material for cold rolling. Previously, titanium-steel composite sheets were only used as end products and had never been used as raw materials for cold rolling.

[0007] S2, Lead strip welding: Remove the titanium layer at the beginning and end of the raw material to expose the steel substrate, and weld the steel substrate to the stainless steel lead strip. S3, Annealing, Shot Blasting and Pickling: The composite plate coils welded in S2 are annealed in a continuous annealing furnace, shot blasted after annealing, and then pickled. S4. Cold rolling: Rolled using a reversible reciprocating rolling mill, and rolled using a constant rolling force mode. S5. Degrease the cold-rolled composite sheet coil; S6. Perform multi-stage vacuum annealing on the degreased composite sheet roll; S7. Flatten the composite sheet roll after vacuum annealing; S8. The flattened composite plate coil is stretched and straightened to obtain a cold-rolled titanium-steel composite plate coil.

[0008] Furthermore, in S1, titanium-steel composite plate coils prepared by direct rolling are preferred as raw materials (for better interface bonding quality and consistency).

[0009] Furthermore, in step S2, the titanium layer within a 300mm range of the beginning and end of the titanium-steel composite plate coil is removed; the welding parameters are determined by the specific grades of the steel substrate and the steel strip.

[0010] Furthermore, in S3, the annealing temperature is 650-750℃.

[0011] Furthermore, in step S3, the pickling is performed using a mixture of HF and HNO3, wherein the concentration of HF is 10-20 g / L, the concentration of HNO3 is 100-170 g / L, and the ratio of HNO3 to HF is ≥10; the acid temperature is controlled between 35-45℃, the rinsing water temperature is controlled within the range of 50-70℃, and the water is dried immediately after pickling.

[0012] Furthermore, in S4, when rolling a single sheet using a reversible reciprocating rolling mill, a tensioning device is added to achieve tensioned rolling.

[0013] Furthermore, in S4, the rolling tension is set according to the same specification of cold-rolled titanium coil, the deformation in a single pass does not exceed 15%, and the cumulative deformation is controlled between 50% and 75%; when the total deformation exceeds 70%, an intermediate annealing is added and rolling continues, and S3 and S4 are repeated; when edge cracks or edge delamination occur during the rolling process, the defective parts are removed by trimming before rolling continues.

[0014] Furthermore, in S5, the degreasing winding tension is reduced by 10% compared to that of cold-rolled titanium coils of the same specification.

[0015] Furthermore, in step S6, the vacuum degree of the multi-step vacuum annealing is ≤4×10⁻⁶. -2 Pa; wherein the temperature of the first stage vacuum annealing is 200℃, the heating rate is 60-100℃ / h, and the holding time is 360-600min; the temperature of the second stage vacuum annealing is 450℃, the heating rate is 60-100℃ / h, and the holding time is 480-840min; the heating rate of the third stage vacuum annealing is 10-50℃ / h, and the temperature is determined by the steel substrate process, and shall not exceed 850℃.

[0016] Furthermore, in S7, the leveling rolling force is applied according to the same specification of cold-rolled titanium coil.

[0017] Furthermore, in S8, the tensile elongation is controlled at 0.2%-1.2%.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The production method of cold-rolled titanium-steel composite plate and coil provided by the present invention does not require a first-pass large reduction or a special high-strength rolling mill. High-performance cold-rolled titanium-steel composite plate and coil can be produced using a conventional production line.

[0019] 2. The production method of cold-rolled titanium-steel composite plate coil provided by the present invention breaks through the bottleneck of industrial production of cold-rolled titanium-steel composite plate and can realize the continuous production of wide cold-rolled titanium-steel composite plate coil.

[0020] 3. The production method of cold-rolled titanium-steel composite plate and coil provided by the present invention has strong process compatibility, does not require a special high-power rolling mill, and adopts a conventional reversible rolling mill, thus avoiding the deformation requirements of the first large pressing in the traditional process.

[0021] 4. The production method of cold-rolled titanium-steel composite plate and coil provided by the present invention uses titanium-steel composite plate and coil as raw material, which is different from the traditional method (usually using cold-rolled titanium and cold-rolled steel plate as raw material), and the raw material cost is lower.

[0022] 5. The production method of cold-rolled titanium-steel composite sheet coil provided by the present invention has stable product quality, good interface bonding consistency, and the finished product has good formability.

[0023] Based on the above reasons, this invention can be widely promoted in fields such as titanium-steel composite plate manufacturing. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] This invention provides a method for producing cold-rolled titanium-steel composite coils, which is an industrial production method that differs from traditional cold-rolled composite plate production processes. It does not require a first-pass large reduction or a special high-power rolling mill, and can produce high-performance cold-rolled titanium-steel composite coils using conventional production lines, thus achieving continuous production of high-performance cold-rolled titanium-steel composite coils.

[0031] like Figure 1 As shown, the production process of the cold-rolled titanium-steel composite plate coil of the present invention is as follows: titanium-steel composite plate raw material → lead strip welding → annealing, shot blasting and pickling → cold rolling → (annealing, shot blasting and pickling → cold rolling) → degreasing → vacuum annealing → leveling → tension straightening → packaging. The present invention uses titanium-steel composite plate coil as the cold-rolled raw material and performs cold rolling according to a conventional process. The finished product specifications can cover the common specifications of existing pure titanium plate coils. The following describes the technology and implementation methods of the present invention in detail according to the process flow, and realizes industrial production through the following steps: S1. Raw material preparation Hot-rolled titanium-steel composite coils prepared by rolling are preferred as cold-rolled raw materials. Compared with titanium-steel composite coils produced by explosive rolling, the latter exhibits a corrugated interface with microcracks and micropores, while the interface of titanium-steel composite coils produced by rolling is denser and smoother, which is beneficial for interface control and thickness control in subsequent processes.

[0032] S2, Lead-in welding Since titanium and steel cannot be welded, when welding stainless steel lead strips, the titanium layer in the composite plate material needs to be removed to expose the steel substrate. A steel-to-steel connection is then used, and the welding parameters are determined by the specific grades of the steel substrate and the steel lead strip.

[0033] S3, Annealing, shot blasting, and pickling The annealing temperature is 650-750℃. The main purpose of annealing at this stage is to relieve stress. Too low a temperature is not conducive to stress removal, while too high a temperature will result in excessive TiC growth at the interface, deteriorating the bonding performance.

[0034] During shot blasting, the actual shot blasting force on the top and bottom surfaces must be consistent, and the actual flatness of the plate surface after shot blasting should be used as the standard.

[0035] Pickling is performed using a mixture of HF and HNO3, with HF concentration at 10-20 g / L and HNO3 concentration at 100-170 g / L, and the HNO3 to HF ratio should be ≥10. The acid temperature should be controlled between 35-45℃. The rinsing water temperature should be controlled within the range of 50-70℃. Drying should be carried out immediately after pickling.

[0036] S4, cold rolled Reversible reciprocating rolling mill is used for rolling, and constant rolling force mode is used for rolling (constant rolling force mode is the control method during rolling).

[0037] A reversible reciprocating rolling mill is used. If a single sheet is being rolled, a tensioning device is required to achieve tensioned rolling. Otherwise, severe warping will occur, making it difficult to continue the rolling process.

[0038] The rolling process employs a constant rolling force mode. Currently, existing thickness gauges on rolling lines cannot detect the thickness of dissimilar bimetallic materials, so AGC (Automatic Thickness Control) is not used during the rolling process; instead, manual thickness measurement is performed after each rolling pass.

[0039] The rolling tension is set according to the same specifications for cold-rolled titanium coils.

[0040] The deformation amount per pass should not exceed 15%, and the cumulative deformation amount should be controlled between 50% and 75%. If it is less than 50%, the interface compound, especially large TiC blocks, cannot be completely broken down and dispersed, which is detrimental to the bonding performance; while if it exceeds 75%, interface damage will occur, leading to delamination of the titanium steel.

[0041] When the total deformation exceeds 70%, an intermediate annealing step is required before rolling can continue. At this time, steps S3 and S4 can be repeated.

[0042] If edge cracks or edge delamination occur during the rolling process, the defective parts must be removed by trimming before rolling can continue. Otherwise, it will lead to strip breakage, and the delamination area will increase as the rolling pressure increases.

[0043] S5, degreasing The degreasing winding tension is reduced by 10% compared to that of cold-rolled titanium coils of the same specification.

[0044] S6, Vacuum Annealing Multi-stage vacuum annealing is employed, with a vacuum degree ≤4×10⁻⁶. -2 Pa. The first step is 200℃, with a heating rate of 60-100℃ / h and a holding time of 360-600min; the second step is 450℃, with a heating rate of 60-100℃ / h and a holding time of 480-840min; the third step has a heating rate of 10-50℃ / h, and the specific temperature is determined by the steel substrate process, but it cannot exceed 850℃, otherwise it will lead to a decrease in the interfacial bonding performance.

[0045] S7, Smooth The leveling rolling force shall be the same as that for cold-rolled titanium coils of the same specifications.

[0046] S8, Straightening The elongation rate of the tension leveling is controlled between 0.2% and 1.2%, depending on the specific plate shape.

[0047] This invention is applicable to the production of titanium-steel composite plates using the direct rolling method. It can be promoted in steel enterprises and can produce products with high bonding strength, showing good prospects for widespread application.

[0048] The present invention discloses a method for producing cold-rolled titanium-steel composite plates, with an average economic benefit of 0.5 million yuan / ton.

[0049] Example 1 The method of this invention for producing cold-rolled 0.1mm TA1+0.4mm St12 composite plates specifically includes the following steps: S1. 1mm TA1+4mm St12 hot-rolled titanium steel composite coils produced by rolling method are selected as cold-rolled raw materials.

[0050] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the substrate St12. Weld the beginning and end substrate St12 together with the stainless steel strip.

[0051] S3. Annealing is performed in a continuous annealing furnace at a temperature of 730℃. After annealing, shot blasting is performed. Following shot blasting, pickling is carried out using 110g / L HNO3 and 10g / L HF, with the acid temperature controlled at 40-45℃. The rinsing water temperature is 70℃. The plate is dried immediately after pickling, ensuring no water stains remain on the surface.

[0052] S4. Cold rolling is performed using a six-roll single-stand mill. Since the total thickness of the raw material is 5mm and the finished product thickness is 0.5mm, the total deformation is 90%, exceeding the maximum cumulative deformation requirement. Therefore, cold rolling is divided into two passes. The first pass rolls from 5.0mm to 1.5mm, with a cumulative deformation of 70%, and the deformation per pass is controlled at approximately 10%. After rolling to 1.5mm, S3 is repeated. The second pass rolls from 1.5mm to a finished product thickness of 0.5mm, with a cumulative deformation of 67%, and the deformation per pass is approximately 10%, with the final pass at approximately 5%. Constant rolling force is used, with the maximum rolling force not exceeding 700t.

[0053] S5. Degreasing is performed using NaOH solution. The tension during degreasing of the 0.5mm cold-rolled titanium coil is 1600 DaN, therefore the winding tension of the composite coil is 1440 DaN. After degreasing, the coil is dried immediately, leaving no water residue on the surface.

[0054] S6. Multi-stage vacuum annealing is adopted, with an actual vacuum degree of 2.1×10⁻⁶. -2 Pa. The heating rate for the first-stage vacuum annealing is 100℃ / h, and the holding temperature is 200℃ for 480 min; the heating rate for the second-stage vacuum annealing is 100℃ / h, and the holding temperature is 450℃ for 720 min; the heating rate for the third-stage vacuum annealing is 10℃ / h, and the holding temperature is 550℃ for 900 min.

[0055] S7. The leveling rolling force is set to 150t according to the 0.5mm TA1 process.

[0056] S8 has a tensile elongation rate of 0.5% and a straight plate shape.

[0057] Through the above steps, a 0.5mm thick TA1 / St12 cold-rolled composite coil was successfully obtained. The surface quality of the product is comparable to that of the same material, the sheet shape is good, the forming performance is good, and it has passed the user's stamping test. There is no delamination at the interface.

[0058] Example 2 The method of this invention for producing cold-rolled 0.5mm TA1+1.5mm St12 composite plates specifically includes the following steps: S1. 1mm TA1+3mm St12 hot-rolled titanium steel composite coils produced by rolling method are selected as cold-rolled raw materials.

[0059] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the Q235 base material. Weld the Q235 base material at both ends to the stainless steel strip.

[0060] S3. Annealing is performed in a continuous annealing furnace at a temperature of 750℃. After annealing, shot blasting is performed. Following shot blasting, pickling is carried out using 150g / L HNO3 and 12g / L HF, with the acid temperature controlled at 35-40℃. The rinsing water temperature is 70℃. The plate is dried immediately after pickling, ensuring no water stains remain on the surface.

[0061] S4. Cold rolling is performed using a six-roll single-stand mill. Since the total thickness of the raw material is 4mm, the finished product thickness is 2mm, and the total deformation is 50%, which does not exceed 75%, only one rolling pass is required. The deformation in the first two passes is approximately 15%, and in the remaining passes, it is approximately 10%-12%. The final pass is approximately 8%. Constant rolling force is used, with a maximum rolling force not exceeding 700t.

[0062] S5. Degreasing is performed using NaOH solution. The tension during degreasing of the 2.0mm cold-rolled titanium coil is 2800 DaN, therefore the winding tension of the composite coil is 2520 DaN. The coil is dried immediately after degreasing, leaving no water residue on the surface.

[0063] S6. Multi-stage vacuum annealing is adopted, with an actual vacuum degree of 1.9 × 10⁻⁶. -2 Pa. The heating rate for the first-stage vacuum annealing is 60℃ / h, and the holding temperature is 200℃ for 360 min; the heating rate for the second-stage vacuum annealing is 100℃ / h, and the holding temperature is 450℃ for 600 min; the heating rate for the third-stage vacuum annealing is 20℃ / h, and the holding temperature is 650℃ for 7800 min.

[0064] S7. The leveling rolling force is set to 220t according to the 2.0mm TA1 process.

[0065] S8 has a tensile elongation rate of 1.2% and a straight plate shape.

[0066] Through the above steps, a TA1 / St12 cold-rolled composite coil with a finished thickness of 2.0mm was successfully obtained. The surface quality of the product is comparable to that of the same material, the sheet shape is good, the forming performance is good, the bending forming inspection shows no delamination at the interface and no cracks on the surface.

[0067] Comparative Example 1 The cold-rolled 0.1mm TA1 + 0.4mm St12 composite plate includes the following steps: S1. 1mm TA1+4mm St12 hot-rolled titanium steel composite coils produced by rolling method are selected as cold-rolled raw materials.

[0068] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the substrate St12. Weld the beginning and end substrate St12 together with the stainless steel strip.

[0069] S3. Annealing is performed in a continuous annealing furnace at a temperature of 730℃. After annealing, shot blasting is performed. Following shot blasting, pickling is carried out using 110g / L HNO3 and 10g / L HF, with the acid temperature controlled at 40-45℃. The rinsing water temperature is 70℃. The plate is dried immediately after pickling, ensuring no water stains remain on the surface.

[0070] S4. Cold rolling was performed using a six-roll single-stand mill. Since the total thickness of the raw material was 5mm and the finished product thickness was 0.5mm, the total deformation was 90%, exceeding the maximum cumulative deformation requirement. Therefore, cold rolling was divided into two passes. The first pass rolled from 5.0mm to 2.0mm, with a cumulative deformation of 60%, and the deformation per pass was controlled at around 10%. After rolling to 2.0mm, S3 was repeated. The second pass rolled from 2.0mm to a finished product thickness of 0.5mm, with a cumulative deformation of 75%, and the deformation per pass was around 18-20%. Cracks appeared at the edges starting from the third pass, and by the fifth pass, the strip broke due to edge cracking. The broken strip was removed, and rolling continued, with the deformation per pass adjusted to 10%. However, when rolling to a thickness of 0.52mm (at which point the cumulative deformation reached 74%), delamination occurred at the interface.

[0071] Comparative Example 2 (deformation less than 50%, failure) The cold-rolled 0.5mm TA1 + 1.5mm St12 composite plate includes the following steps: S1. 0.9mmTA1+2.7mmSt12 hot-rolled titanium steel composite coils produced by rolling are selected as cold-rolled raw materials.

[0072] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the Q235 base material. Weld the Q235 base material at both ends to the stainless steel strip.

[0073] S3. Annealing is performed in a continuous annealing furnace at a temperature of 750℃. After annealing, shot blasting is performed. Following shot blasting, pickling is carried out using 150g / L HNO3 and 12g / L HF, with the acid temperature controlled at 35-40℃. The rinsing water temperature is 70℃. The plate is dried immediately after pickling, ensuring no water stains remain on the surface.

[0074] S4. Cold rolling is performed using a six-roll single-stand mill. Since the total thickness of the raw material is 3.6mm, the finished product thickness is 2mm, and the total deformation is 44%, which does not exceed 75%, only one rolling pass is required. The deformation per pass is approximately 8%-10%. Constant rolling force mode is used, with a maximum rolling force not exceeding 700t.

[0075] S5. Degreasing is performed using NaOH solution. The tension during degreasing of the 2.0mm cold-rolled titanium coil is 2800 DaN, therefore the winding tension of the composite coil is 2520 DaN. The coil is dried immediately after degreasing, leaving no water residue on the surface.

[0076] S6. Multi-stage vacuum annealing is adopted, with an actual vacuum degree of 1.9 × 10⁻⁶. -3 Pa. The heating rate for the first-stage vacuum annealing is 60℃ / h, and the holding temperature is 200℃ for 360 min; the heating rate for the second-stage vacuum annealing is 100℃ / h, and the holding temperature is 450℃ for 600 min; the heating rate for the third-stage vacuum annealing is 20℃ / h, and the holding temperature is 650℃ for 7800 min.

[0077] S7. The leveling rolling force is set to 200t according to the 2.0mm TA1 process.

[0078] S8, with a tensile elongation rate of 1.0%, delamination was found in some titanium-steel composite plates during straightening.

[0079] The finished product was tested for bending and the interface showed signs of delamination, rendering it unusable.

[0080] Comparative Example 3 (annealing temperature too high, failure) The method of this invention for producing cold-rolled 0.1mm TA1+0.4mm St12 composite plates specifically includes the following steps: S1. 1mm TA1+4mm St12 hot-rolled titanium steel composite coils produced by rolling method are selected as cold-rolled raw materials.

[0081] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the substrate St12. Weld the beginning and end substrate St12 together with the stainless steel strip.

[0082] S3. Annealing is performed in a continuous annealing furnace at a temperature of 730℃. After annealing, shot blasting is performed. Following shot blasting, pickling is carried out using 110g / L HNO3 and 10g / L HF, with the acid temperature controlled at 40-45℃. The rinsing water temperature is 70℃. The plate is dried immediately after pickling, ensuring no water stains remain on the surface.

[0083] S4. Cold rolling is performed using a six-roll single-stand mill. Since the total thickness of the raw material is 5mm and the finished product thickness is 0.5mm, the total deformation is 90%, exceeding the maximum cumulative deformation requirement. Therefore, cold rolling is divided into two passes. The first pass rolls from 5.0mm to 1.5mm, with a cumulative deformation of 70%, and the deformation per pass is controlled at approximately 10%. After rolling to 1.5mm, S3 is repeated. The second pass rolls from 1.5mm to a finished product thickness of 0.5mm, with a cumulative deformation of 67%, and the deformation per pass is approximately 10%, with the final pass at approximately 5%. Constant rolling force is used, with the maximum rolling force not exceeding 700t.

[0084] S5. Degreasing is performed using NaOH solution. The tension during degreasing of the 0.5mm cold-rolled titanium coil is 1600 DaN, therefore the winding tension of the composite coil is 1440 DaN. After degreasing, the coil is dried immediately, leaving no water residue on the surface.

[0085] S6. Multi-stage vacuum annealing is adopted, and the actual vacuum degree is 2.1×10⁻⁶. -2 Pa. The heating rate for the first-stage vacuum annealing is 100℃ / h, and the holding temperature is 200℃ for 480 min; the heating rate for the second-stage vacuum annealing is 100℃ / h, and the holding temperature is 450℃ for 720 min; the heating rate for the third-stage vacuum annealing is 10℃ / h, and the holding temperature is 900℃ for 720 min.

[0086] S7. The leveling rolling force is set to 150t according to the 0.5mm TA1 process.

[0087] S8, with a tension and straightening elongation rate of 0.5%.

[0088] During leveling and straightening, some areas were found to have interface delamination. When samples were taken for bending tests, interface delamination was found, rendering the area unusable.

[0089] Comparative Example 4 Cold-rolled 0.5mm TA1 + 1.5mm St12 composite plate S1. 1mm TA1+3mm St12 hot-rolled titanium steel composite coils produced by rolling method are selected as cold-rolled raw materials.

[0090] S2. Remove the titanium layer within a 300mm range at the beginning and end of the hot-rolled titanium-steel composite coil to expose the Q235 base material. Weld the Q235 at both ends to the stainless steel strip.

[0091] S3. Annealing is performed in a bell-type furnace at 850℃ for 15 hours. Pickling is done using 150g / L HNO3 and 12g / L HF, with the acid temperature controlled at 35-40℃. Rinse with 70℃ water. The boards are dried immediately after pickling, leaving no water residue on the surface.

[0092] S4. Cold rolling is performed using a six-roll single-stand mill. Since the total thickness of the raw material is 4mm, the finished product thickness is 2mm, and the total deformation is 50%, which does not exceed 75%, only one rolling pass is required. The deformation in the first two passes is approximately 15%, and in the remaining passes, it is approximately 10%-12%. The final pass is approximately 8%. Constant rolling force is used, with a maximum rolling force not exceeding 700t.

[0093] S5. Degreasing is performed using NaOH solution. The tension during degreasing of the 2.0mm cold-rolled titanium coil is 2800 DaN, therefore the winding tension of the composite coil is 2520 DaN. The coil is dried immediately after degreasing, leaving no water residue on the surface.

[0094] S6. Multi-stage annealing is adopted, and the actual vacuum degree is 1.9×10⁻⁶. -2 Pa. The first step has a heating rate of 60℃ / h and a holding time of 200℃ for 360min; the second step has a heating rate of 100℃ / h and a holding time of 450℃ for 600min; the third step has a heating rate of 20℃ / h and a holding time of 650℃ for 7800min.

[0095] S7. The leveling rolling force is set to 220t according to the 2.0mm TA1 process.

[0096] S8 has a tensile elongation rate of 1.2% and a straight plate shape.

[0097] The finished product was tested for bending and the interface showed signs of delamination, rendering it unusable.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing cold-rolled titanium-steel composite sheet coils, characterized in that, The steps include the following: S1. Raw material preparation: Select titanium-steel composite plate coils as cold-rolled raw materials; S2, Lead strip welding: Remove the titanium layer at the beginning and end of the raw material to expose the steel substrate, and weld the steel substrate to the stainless steel lead strip. S3, Annealing, Shot Blasting and Pickling: The composite plate coils welded in S2 are annealed in a continuous annealing furnace, shot blasted after annealing, and then pickled. S4. Cold rolling: Rolled using a reversible reciprocating rolling mill, and rolled using a constant rolling force mode. S5. Degrease the cold-rolled composite sheet coil; S6. Perform multi-stage vacuum annealing on the degreased composite sheet roll; S7. Flatten the composite sheet roll after vacuum annealing; S8. The flattened composite plate coil is stretched and straightened to obtain a cold-rolled titanium-steel composite plate coil. In S1, hot-rolled titanium-steel composite plate coils produced by rolling are used as raw materials; In step S3, the annealing temperature is 650-750℃; In S4, the rolling tension is set according to the same specification of cold-rolled titanium coil, the deformation in a single pass does not exceed 15%, and the cumulative deformation is controlled between 50% and 75%. When the total deformation exceeds 70%, an intermediate annealing is added and rolling continues. At this time, S3 and S4 are repeated. When edge cracks or edge delamination occur during the rolling process, the defective parts are removed by trimming before rolling continues. In step S6, the vacuum degree of the multi-step vacuum annealing is ≤4×10⁻⁶. -2 Pa; wherein the temperature of the first stage vacuum annealing is 200℃, the heating rate is 60-100℃ / h, and the holding time is 360-600min; the temperature of the second stage vacuum annealing is 450℃, the heating rate is 60-100℃ / h, and the holding time is 480-840min; the heating rate of the third stage vacuum annealing is 10-50℃ / h, and the temperature is determined by the steel substrate process, and shall not exceed 850℃.

2. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In step S2, the titanium layer within a 300mm range of the beginning and end of the titanium-steel composite plate coil is removed; the welding parameters are determined by the specific grades of the steel substrate and the steel strip.

3. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In step S3, pickling is performed using a mixture of HF and HNO3, with the HF concentration being 10-20 g / L and the HNO3 concentration being 100-170 g / L, and the ratio of HNO3 to HF being ≥10; the acid temperature is controlled between 35-45℃, the rinsing water temperature is controlled within the range of 50-70℃, and the product is dried immediately after pickling.

4. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In S4, when a single sheet is being rolled using a reversible reciprocating rolling mill, a tensioning device is added to achieve tensioned rolling.

5. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In S5, the degreasing winding tension is reduced by 10% compared to that of cold-rolled titanium coils of the same specification.

6. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In S7, the leveling rolling force is applied according to the same specifications of cold-rolled titanium coil.

7. The method for producing cold-rolled titanium-steel composite sheet coils according to claim 1, characterized in that, In S8, the elongation rate is controlled between 0.2% and 1.2%.

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