A production method for preventing longitudinal stripe on surface of titanium-steel composite plate

Abstract

The application provides a production method for preventing longitudinal stripes on the surface of a titanium-steel composite plate, and relates to the field of titanium-steel composite plate manufacturing, and comprises the following steps: S1, raw material preparation: determining the size of a titanium plate and a steel blank, the width of the titanium plate = the width of a finished product + 50 mm, the width of the steel blank = the width of the titanium plate + a width expansion amount + the width of a frame * 2, the width expansion amount y = 8.83 * ln(x) - 4.4, x is a compression ratio greater than or equal to 5; S2, single-side coating of the titanium plate with a separating agent with a particle size less than or equal to 10 microns; S3, blank assembly: reserving a width expansion space between the titanium plate and the frame, fixing the titanium plate through a welding positioning block, and vacuumizing to less than or equal to 1 * 10 Pa; S4, heating to 850-950 DEG C; S5, single-pass deformation less than or equal to 15% before the cumulative deformation is less than or equal to 30% during rolling, and no side pressure is added during the whole process; and S6, plate separation and cutting. The application reserves a width expansion space and controls the initial deformation amount, so that the titanium plate is prevented from being extruded by the frame to form longitudinal stripes during elongation, the pushing and grinding process is saved, the surface quality and the yield are improved, and the problem that the titanium plate is extruded by the frame to form longitudinal stripes on the surface due to the deformation difference between the titanium and the steel during blank assembly and rolling can be solved.

Description

Technical Field

[0001] This invention relates to the field of titanium-steel composite plate rolling technology, specifically to a production method for preventing longitudinal stripes on the surface of titanium-steel composite plates. It is a production method for titanium-steel composite plates used in billet rolling processes, particularly for the prevention and control of longitudinal stripes on the surface of titanium plates during the rolling process. Background Technology

[0002] Titanium-steel composite plates, possessing the superior properties of both titanium and steel, have been widely used in petroleum, chemical, and marine engineering fields. There are four main production methods for titanium-steel composite plates: explosive bonding, diffusion bonding, explosive-rolling, and rolling bonding. Among these, rolling bonding has become the main development direction for titanium-steel composite plate production due to its advantages of being environmentally friendly, efficient, and low-cost.

[0003] When producing titanium-steel composite plates using the rolling process, to avoid warping caused by incoordination in the deformation of the two materials, the following methods are typically used: Figure 2 The method of symmetrical assembly is shown. During the rolling process, the titanium billet is wrapped in the steel billet. Due to the difference in deformation resistance and elongation between the two, the elongation of titanium in the width direction is much higher than that of steel in the early stage of rolling. When the elongation of the titanium billet is blocked by the frame, longitudinal stripes with a depth of 0.1-0.5 mm are formed along the length of the rolled piece. Figure 4 In severe cases, these longitudinal stripes can cover the entire surface of the board and must be removed by grinding. Furthermore, because the stripes are deep, a greater amount of grinding is needed to remove them completely. However, excessive grinding not only increases production costs but may also lead to the risk of the board thickness falling below the specified lower limit, which is detrimental to the normal sale of the product.

[0004] Currently, research on the production of titanium-steel composite plates by rolling mainly focuses on improving interfacial bonding strength, but no effective solution has yet been found to address surface longitudinal striations. Therefore, developing a method for preventing longitudinal striations during billet rolling is crucial for improving product quality and economic efficiency. Summary of the Invention

[0005] To address the technical problem of hindered width expansion and longitudinal stripes in titanium plates caused by the difference in deformation resistance between titanium and steel during billet rolling, this invention provides a production method to prevent longitudinal stripes on the surface of titanium-steel composite plates, namely a solution by reserving width expansion space and controlling the initial deformation amount.

[0006] The technical means employed in this invention are as follows: A method for preventing longitudinal stripes on the surface of titanium-steel composite plates includes the following steps: S1. Raw material preparation: Prepare two titanium plates, two steel billets, and a frame. Determine the dimensions of the titanium plates and steel billets, including the width of the titanium plates and the width of the steel billets. The width of the titanium plates = finished product width + 50mm, and the width of the steel billets = width of the titanium plates + titanium plate width extension + frame width × 2. Remove oxide scale and oil stains from the surfaces of the titanium plates, steel billets, and frame. S2. After wiping the oil stains off the surface of the titanium plate with anhydrous ethanol, apply a release agent to one side and let it dry. S3. Assembly: Assemble the billets symmetrically in the following order from top to bottom: steel plate, titanium medium plate, titanium medium plate, steel plate; stack two titanium medium plates symmetrically between two steel billets, and place a frame around the outer perimeter of the two titanium medium plates. A space is reserved between the inner side of the frame and the titanium medium plate to accommodate the expansion of the titanium medium plate during rolling. Weld at least two positioning blocks to each side of the titanium medium plate along its length to fix its position; after welding the upper and lower steel plates to the frame, connect a vacuum device and evacuate to 1×10⁻⁶. Below Pa; S4. Heat the assembled billet to 850℃-950℃; S5. Roll the heated composite billet: When the cumulative deformation is ≤30%, the single-pass deformation is ≤15% and no side pressure is applied throughout the process, a titanium-steel composite plate is prepared. S6. Separate the rolled titanium-steel composite plates and remove them from the production line.

[0007] Furthermore, in S1, the width expansion is calculated based on the compression ratio x using the formula y=8.83×ln(x)-4.4, where x is the compression ratio and x≥5.

[0008] Furthermore, in S2, the release agent is composed of powdered metal oxides and organic matter, wherein the organic matter includes binders and dispersants; the coating thickness of the release agent is 0.5 mm to 1.5 mm.

[0009] Furthermore, the oxide particles in the release agent have a particle size ≤10μm.

[0010] Furthermore, in S3, the width of the extended space is 1.05-1.2 times the width of the titanium plate, with a safety margin reserved; The positioning block is welded to the end corner area along the length of the titanium plate, which is the most effective way to prevent movement.

[0011] Furthermore, in S4, the heating temperature is 850℃-950℃.

[0012] Furthermore, in S4, the heating temperature is 900°C.

[0013] Furthermore, in S5, the maximum deformation per pass is controlled to be within 10%.

[0014] Furthermore, in step S6, the rolled titanium-steel composite plate is cut according to the finished width, the frame and the composite plate are separated according to the flaw detection results, and then precision cut according to the finished size.

[0015] To address the longitudinal stripe problem caused by inconsistent deformation of titanium steel during billet rolling, coordinated deformation is achieved by dynamically reserving a wide extension space, constraining the displacement of the titanium plate, and controlling the initial deformation amount. Specifically, this includes: 1. Dynamic Dimensioning Design: (1) Width of titanium plate = finished product width + 50mm (plate shape allowance); (2) Steel billet width = titanium plate width + width extension + frame width × 2, where the width extension is calculated based on the plastic flow law of titanium (y = 8.83 × ln(x) - 4.4, x is the compression ratio and x ≥ 5), to ensure that the titanium plate can extend freely without being squeezed by the frame; 2. Titanium plate displacement constraint: During billet assembly, at least two positioning blocks are welded on both sides of the length direction of the titanium plate to prevent the titanium plate from shifting within the cavity and causing skewing during the initial rolling stage. 3. Deformation Coordination Control: (1) Before the cumulative deformation of rolling is ≤30%, the deformation of a single pass is ≤15% (preferably ≤10%) to reduce the rapid widening trend of titanium plates; (2) No lateral pressure is applied throughout the entire process to avoid additional width direction constraints; 4. Interface isolation guarantee: The particle size of the release agent is ≤10μm to ensure flowability and avoid surface roughness after rolling (the effect of flow obstruction is similar to that of border constraint).

[0016] Compared with the prior art, the present invention has the following advantages: 1. Completely eliminate vertical stripes: Through dynamic design with ample space and control of initial deformation, the titanium plate can extend freely without touching the edge, thus avoiding compression stripes at the source.

[0017] 2. Improve dimensional accuracy: Positioning blocks are welded to fix the titanium plate, solving the problem of plate shape deviation caused by rolling movement.

[0018] 3. Significantly reduces costs and increases efficiency: Eliminating the grinding process reduces costs by ≥100 yuan / m 2 The yield rate is increased by ≥5%.

[0019] 4. Ensure surface quality: The release agent has a particle size of ≤10μm to avoid surface roughness defects caused by coarse particles.

[0020] 5. The process has strong universality: Applicable to rolling of various titanium-steel composite plates with a compression ratio ≥5, with a width extension calculation error of <2%.

[0021] Based on the above reasons, this invention can be widely promoted in fields such as titanium-steel composite plate manufacturing. Attached Figure Description

[0022] 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.

[0023] Figure 1 This is a flowchart of the method of the present invention.

[0024] Figure 2 This is a schematic diagram of the rolling process using a symmetrical material assembly method according to the present invention.

[0025] Figure 3 This is a schematic diagram of the edge welding positioning blocks at both ends of the titanium plate of the present invention.

[0026] Figure 4 This is a morphological diagram of longitudinal stripes.

[0027] In the diagram: 1. Steel billet; 2. Titanium plate; 3. Separating agent; 4. Frame; 5. Steel pipe; 6. Enclosure; 7. Positioning block. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth 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 listed in one figure… This invention provides a production method for preventing longitudinal stripes on the surface of titanium-steel composite plates. This method can avoid the appearance of longitudinal stripes on the surface of titanium plates during symmetrical rolling, thus enabling normal sales.

[0032] like Figure 1 As shown, the process flow for producing titanium-steel composite plates using the rolling method of this invention is as follows: preparation of raw materials such as composite titanium plates, base steel billets, and frames → coating and isolating the composite titanium plates → symmetrical assembly of the base steel billets and composite titanium plates → heating of the composite billet → rolling of the composite billet → separation and removal from the production line. The technology and implementation methods of this invention are described in detail below according to the process flow: S1. Raw material preparation.

[0033] The raw material preparation for titanium-steel composite plates mainly includes titanium medium plates and steel billets. The dimensions of the titanium medium plates and steel billets are determined, and their thicknesses are primarily based on the compression ratio. The compression ratio is typically above 5; below 5, the titanium-steel bonding will be poor. The raw material thickness is usually calculated by working backwards from the finished product thickness, based on the proportional deformation of titanium and steel. For example, if the finished product thickness is 2mm TA2 + 8mm Q235, and the compression ratio is 15, based on the proportional deformation calculation, the raw material thickness of the titanium medium plate should be 30mm, and the raw material thickness of the Q235 steel billet should be 120mm.

[0034] The width design of titanium plates and billets must take into account the width expansion of titanium. Generally, the higher the compression ratio, the greater the width expansion. Therefore, space needs to be left for the titanium to expand during the design. Based on experience, the width expansion of titanium is roughly logarithmically related to the compression ratio, with the width expansion y = 8.83 × ln(x) - 4.4, where x is the compression ratio, and x ≥ 5. In this case, the billet width = titanium plate width + titanium plate width expansion + edge width × 2, and the titanium plate width = finished product width + 50mm. The 50mm increase is a reasonable allowance to account for plate shape problems such as camber and edge waviness that may occur during the rolling process of the titanium-steel composite plate. For example, to obtain a titanium-steel composite plate with a finished width of 1500mm, the width of the titanium middle plate is set to 1550mm. With a compression ratio of 5, the width of the titanium is approximately 9.8mm. Assuming the frame width is 50mm, the width of the steel billet should be 1550 + 9.8 + 50 × 2 = 1659.8 ≈ 1660mm.

[0035] The oxide scale and oil stains on the surface of the titanium plate, steel billet and frame need to be removed.

[0036] The width of the gap between the frame and the titanium plate (the width of the expansion space) = the expansion amount of the titanium plate × (1.05-1.2) times.

[0037] The formula for width expansion, y = 8.83 × ln(x) - 4.4 (x ≥ 5), is based on fitting data from 20 sets of titanium plate rolling tests (compression ratio 5~20, temperature 900℃). As shown in Table 1, the error between the measured width expansion and the calculated value is < 2%.

[0038] Table 1

[0039] S2, The surface of the titanium plate is coated with a release agent.

[0040] After wiping the oil stains off the surface of the titanium middle plate with anhydrous ethanol, apply release agent 3 to one side and allow it to dry to form a release layer. The release agent is usually composed of powdered metal oxides and organic substances such as binders and dispersants. Uniform coating is required, with a typical coating thickness of 0.5mm to 1.5mm. If the coating thickness is less than 0.5mm, there is a risk of adhesion, and it will not effectively separate the two titanium middle plates. Release agents thicker than 1.5mm are prone to peeling off after drying. The particle size of the oxides in the release agent should be ≤10μm.

[0041] S3, billet assembly.

[0042] use Figure 2The titanium-steel composite plate is assembled using a symmetrical assembly method as shown. The symmetrical assembly follows the order from top to bottom: steel plate, titanium intermediate plate, titanium intermediate plate, and steel plate. Two titanium intermediate plates are symmetrically stacked between two steel billets. A frame is placed around the outer perimeter of the two titanium intermediate plates, with space reserved between the inner sides of the frame and the titanium intermediate plates to accommodate the expansion of the titanium intermediate plates during rolling.

[0043] Align the center point of the titanium middle plate 2 with the center point of the steel base plate (steel billet 1). Then, based on the gap between the titanium middle plate and the frame 4 (the reserved space), prepare small titanium plates of equal thickness (positioning blocks 7) in advance and weld them to both sides of the frame of the titanium middle plate to fix the titanium middle plate (e.g., Figure 3 (As shown). At least two positioning blocks are set on each side of the titanium plate along its length to fix its position. For example, if the gap between the titanium plate and the frame is 10mm, then a small piece of titanium plate with a thickness of 10mm is required. The positioning blocks are welded to the corner areas 100mm from the edge at both ends of the titanium plate along its length. If not fixed, the titanium plate may move within the blank cavity during billet movement or rolling, resulting in uncontrolled final plate shape and dimensional accuracy.

[0044] After the titanium billet is fixed, the upper steel substrate is placed and overlaps with the lower steel substrate.

[0045] After welding the upper and lower steel substrates to the frame, connect the steel pipe 5 to the frame, and then connect the external vacuum equipment to... Figure 2 The steel pipes are connected in group 5, and internal vacuum treatment (of the frame, titanium plate, and space between the steel billets) is performed. When the vacuum degree is ≤1×10⁻⁶... After Pa, the steel pipe is sealed (forming a sealing section 6) to maintain an internal vacuum.

[0046] S4. Heating.

[0047] Because of the limited solid solubility between titanium and steel, brittle intermetallic compounds easily form at the interface, compromising the bond strength. Therefore, the heating temperature is typically controlled between 850℃ and 950℃, preferably 900℃. Above 950℃, diffusion intensifies, and the number of compounds increases dramatically, while below 850℃, the load on the rolling mill increases.

[0048] S5, Rolling.

[0049] No side pressure is applied during the rolling process.

[0050] When the cumulative deformation is less than 30%, use the smallest possible single-pass deformation, ideally below 15%, and preferably below 10%. Once the cumulative deformation exceeds 30%, further consideration is unnecessary. This is because in the early rolling passes, before the titanium and steel have fully bonded, there is no constraint between the titanium and the steel substrate except for friction. Since the deformation resistance of titanium is much lower than that of the steel substrate, a large single-pass deformation will cause the titanium to quickly fill the edge, forming longitudinal stripes after being constrained and compressed by the edge. When the cumulative deformation reaches 30% or more, the titanium and steel have formed a preliminary bond, their synergistic effect is enhanced, and longitudinal stripes no longer occur.

[0051] S6, Board offline.

[0052] The rolled titanium-steel composite plate is cut according to the finished width. Cutting needs to be done in two stages. First, based on the flaw detection results, the boundary positions of the frame and the titanium-steel composite plate are determined, and the first cut is performed, primarily for separating the plates. Then, the upper and lower layers of the titanium-steel composite plate are separated by applying a release agent (such as...). Figure 2 After being divided into two pieces (as shown in the image), it is then precisely cut according to the finished product dimensions.

[0053] 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.

[0054] The production method of titanium-steel composite plate according to the present invention can obtain titanium-steel composite plates with good surface finish. The average economic benefit can reach 0.5 million yuan / ton.

[0055] Example 1 The method of this invention is used to roll a composite plate of (2mm TA2 + 8mm Q235) × 1500mm × L, which specifically includes the following steps: S1. The design frame width is 50mm, and the compression ratio is 14. Based on the finished product thickness, the titanium medium plate thickness is determined to be 28mm, and the Q235 steel billet thickness is 112mm. Based on empirical calculations, the titanium medium plate width extension is 18.9mm. The finished width of the titanium-steel composite plate is 1500mm, therefore the titanium medium plate width is 1550mm, and the Q235 steel billet width is 1550 + 18.9 + 50 × 2 = 1668.9 ≈ 1670mm.

[0056] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 0.5 mm. The oxide particles in the release agent have a particle size of 1 μm.

[0057] S3, according to Figure 2 As shown, the titanium middle plate is assembled according to the corner area. Figure 3Four 10mm thick positioning titanium blocks were welded as shown. After the preform assembly was completed, the interior was subjected to vacuum treatment with a vacuum degree of 0.008Pa.

[0058] S4. Heating temperature is 900℃.

[0059] S5, the reduction amounts for the first four passes are 5%, 8%, 10%, and 12%, respectively. At this point, the cumulative deformation has reached 30%. Subsequent rolling is carried out automatically according to the model settings, and no side pressure is used throughout the rolling process.

[0060] S6. Based on the boundaries determined by flaw detection, separate the composite panels and cut them to a fixed length of 1500mm. Inspect the surface; no longitudinal stripe defects are found.

[0061] Example 2 The method of this invention is used to roll out a composite plate of (1.2mm TA2 + 10mm Q235) × 1700mm × L, which specifically includes the following steps: S1. The design frame width is 50mm, and the compression ratio is 12. Based on the finished product thickness, the titanium medium plate thickness is determined to be 14.4mm, and the Q235 steel billet thickness is 120mm. Based on empirical calculations, the titanium medium plate width extension is 17.5mm. The finished width of the titanium-steel composite plate is 1700mm, therefore the titanium medium plate width is 1750mm, and the Q235 steel billet width is 1750 + 17.5 + 50 × 2 = 1867.5 ≈ 1868mm.

[0062] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 1.0 mm. The oxide particles in the release agent have a particle size of 500 nm.

[0063] S3, according to Figure 2 As shown, the titanium middle plate is assembled according to the corner area. Figure 3 Four 9mm thick positioning titanium blocks were welded as shown. After the preform assembly was completed, the interior was subjected to vacuum treatment with a vacuum degree of 0.007Pa.

[0064] S4. Heating temperature is 910℃.

[0065] S5, the reduction amounts for the first four passes are 8%, 8%, 10%, and 10% respectively. At this point, the cumulative deformation has reached 30%. Subsequent rolling is carried out automatically according to the model settings, and no side pressure is used throughout the rolling process.

[0066] S6. Based on the boundaries determined by flaw detection, separate the composite panels and cut them to a fixed length of 1700mm. Inspect the surface; no longitudinal stripe defects are found.

[0067] Comparative Example 1 (No space reserved in the width direction) The rolling process for producing a finished (2mm TA2 + 8mm Q235) × 1500mm × L composite panel includes the following steps: S1. The design frame width is 50mm, the compression ratio is 14, and the thickness of the titanium medium plate is determined to be 28mm based on the finished product thickness. The thickness of the Q235 steel billet is 112mm. The finished width of the titanium-steel composite plate is 1500mm, so the width of the titanium medium plate is 1550mm, and the width of the Q235 steel billet is 1550 + 50 × 2 = 1650mm.

[0068] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 0.5 mm. The oxide particles in the release agent have a particle size of 1 μm.

[0069] S3, according to Figure 2 As shown, the titanium middle plate is aligned with the center point of the Q235 steel base plate, with no gap between it and the frame. After the assembly is completed, the interior is subjected to vacuum treatment with a vacuum degree of 0.008 Pa.

[0070] S4. Heating temperature is 900℃.

[0071] S5, the reduction amounts for the first four passes are 5%, 8%, 10%, and 12%, respectively. At this point, the cumulative deformation has reached 30%. Subsequent rolling is carried out automatically according to the model settings, and no side pressure is used throughout the rolling process.

[0072] S6. Based on the boundaries determined by flaw detection, separate the composite panels and cut them to a fixed length of 1500mm. Inspect the surface; longitudinal stripe defects are found, and the stripes become more pronounced (deeper) towards the edges.

[0073] Comparative Example 2 (Inappropriate Rolling Process Settings) The rolled product (1.2mm TA2 + 10mm Q235) × 1700mm × L composite plate specifically includes the following steps: S1. The design frame width is 50mm, and the compression ratio is 12. Based on the finished product thickness, the titanium medium plate thickness is determined to be 14.4mm, and the Q235 steel billet thickness is 120mm. Based on empirical calculations, the titanium medium plate width extension is 17.5mm. The finished width of the titanium-steel composite plate is 1700mm, therefore the titanium medium plate width is 1750mm, and the Q235 steel billet width is 1750 + 17.5 + 50 × 2 = 1867.5 ≈ 1868mm.

[0074] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 1.0 mm. The oxide particles in the release agent have a particle size of 500 nm.

[0075] S3, according to Figure 2 As shown, the titanium middle plate is assembled according to the corner area. Figure 3 Four 9mm thick positioning titanium blocks were welded as shown. After the preform assembly was completed, the interior was subjected to vacuum treatment with a vacuum degree of 0.007Pa.

[0076] S4. Heating temperature is 910℃.

[0077] S5, the reduction amounts for the first three passes are 16%, 20%, and 20% respectively, and no side pressure is used throughout the rolling process.

[0078] S6. Based on the boundaries determined by flaw detection, separate the composite panels and cut them to a fixed length of 1700mm. Inspect the surface; obvious longitudinal stripe defects are found within 500mm of the edge.

[0079] Comparative Example 3 (Improper rolling process, large particle size of release agent) The rolled product (1.2mm TA2 + 10mm Q235) × 1700mm × L composite plate specifically includes the following steps: S1. The design frame width is 50mm, and the compression ratio is 12. Based on the finished product thickness, the titanium medium plate thickness is determined to be 14.4mm, and the Q235 steel billet thickness is 120mm. Based on empirical calculations, the titanium medium plate width extension is 17.5mm. The finished width of the titanium-steel composite plate is 1700mm, therefore the titanium medium plate width is 1750mm, and the Q235 steel billet width is 1750 + 17.5 + 50 × 2 = 1867.5 ≈ 1868mm.

[0080] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 1.0 mm. The oxide particles in the release agent have a particle size of 100 μm.

[0081] S3, according to Figure 2 As shown, the titanium middle plate is assembled according to the corner area. Figure 3 Four 9mm thick positioning titanium blocks were welded as shown. After the preform assembly was completed, the interior was subjected to vacuum treatment with a vacuum degree of 0.007Pa.

[0082] S4. Heating temperature is 910℃.

[0083] S5, the reduction amounts for the first three passes are 16%, 20%, and 20% respectively, and no side pressure is used throughout the rolling process.

[0084] S6. Based on the boundaries determined by flaw detection, the composite plates are separated and cut to a fixed length of 1700mm. Upon inspection of the surface, due to excessive single-pass reduction and release agent particle size reaching 100μm (>10μm), the flowability during rolling is poor, resulting in indentations on the titanium plate surface, and longitudinal stripes and roughness defects appearing on the finished product surface.

[0085] Comparative Example 4 (without positioning block) The method of this invention is used to roll a composite plate of (2mm TA2 + 8mm Q235) × 1500mm × L, which specifically includes the following steps: S1. The design frame width is 50mm, and the compression ratio is 14. Based on the finished product thickness, the titanium medium plate thickness is determined to be 28mm, and the Q235 steel billet thickness is 112mm. Based on empirical calculations, the titanium medium plate width extension is 18.9mm. The finished width of the titanium-steel composite plate is 1500mm, therefore the titanium medium plate width is 1550mm, and the Q235 steel billet width is 1550 + 18.9 + 50 × 2 = 1668.9 ≈ 1670mm.

[0086] S2. After wiping the titanium plate clean with anhydrous ethanol, apply a release agent and allow it to air dry. The release agent coating thickness is 0.5 mm. The oxide particles in the release agent have a particle size of 1 μm.

[0087] S3, according to Figure 2 The blanks are assembled as shown, without welding the positioning blocks. After assembly, the interior is subjected to vacuum treatment with a vacuum level of 0.008 Pa.

[0088] S4. Heating temperature is 900℃.

[0089] S5, the reduction amounts for the first three passes are 15%, 8%, and 10% respectively. At this point, the cumulative deformation has reached 30%. Subsequent rolling is carried out automatically according to the model settings, and no side pressure is used throughout the rolling process.

[0090] S6. Based on the boundaries determined by flaw detection, the composite plates are separated and cut to a fixed length of 1500mm. Surface inspection revealed that the titanium plate had shifted during production, resulting in longitudinal stripes on one side of the finished product.

[0091] 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 preventing longitudinal stripes on the surface of titanium-steel composite plates, characterized in that, Includes the following steps: S1. Raw material preparation: Prepare two titanium plates, two steel billets, and a frame. Determine the dimensions of the titanium plates and steel billets, including the width of the titanium plates and the width of the steel billets. The width of the titanium plates = finished product width + 50mm, and the width of the steel billets = width of the titanium plates + titanium plate width extension + frame width × 2. Remove oxide scale and oil stains from the surfaces of the titanium plates, steel billets, and frame. S2. After wiping the oil stains off the surface of the titanium plate with anhydrous ethanol, apply a release agent to one side and let it dry. S3. Assembly: Assemble the billets symmetrically in the following order from top to bottom: steel plate, titanium medium plate, titanium medium plate, steel plate; stack two titanium medium plates symmetrically between two steel billets, and place a frame around the outer perimeter of the two titanium medium plates. A space is reserved between the inner side of the frame and the titanium medium plate to accommodate the expansion during rolling. Weld at least two positioning blocks to each side of the titanium medium plate along its length to fix its position; the width of the expansion space is 1.05-1.2 times the expansion amount of the titanium medium plate; the positioning blocks are welded to the end corners of the titanium medium plate along its length; after welding the upper and lower steel plates to the frame, connect a vacuum device and evacuate to 1×10⁻⁶. -2 Below Pa; S4. Heat the assembled billet to 850℃-950℃; S5. Roll the heated composite billet: When the cumulative deformation is ≤30%, the maximum deformation per pass is controlled within 10% and no side pressure is applied throughout the process to prepare a titanium-steel composite plate. S6. Separate the rolled titanium-steel composite plates and remove them from the production line; In S1, the width expansion is calculated based on the compression ratio x using the formula y=8.83×ln(x)-4.4, where x is the compression ratio and x≥5.

2. The production method for preventing longitudinal stripes on the surface of titanium-steel composite plates according to claim 1, characterized in that, In step S2, the release agent is composed of powdered metal oxides and organic matter, including binders and dispersants; the coating thickness of the release agent is 0.5 mm to 1.5 mm.

3. The production method for preventing longitudinal stripes on the surface of titanium-steel composite plates according to claim 2, characterized in that, The oxide particles in the release agent have a particle size ≤10μm.

4. The production method for preventing longitudinal stripes on the surface of titanium-steel composite plates according to claim 1, characterized in that, In step S4, the heating temperature is 900°C.

5. The production method for preventing longitudinal stripes on the surface of titanium-steel composite plates according to claim 1, characterized in that, In step S6, the rolled titanium-steel composite plate is cut according to the finished width. The frame and composite plate are separated according to the flaw detection results, and then precision cut according to the finished size.

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