Manufacturing method of rolled titanium-steel composite profile and titanium-steel composite profile

Abstract

The invention discloses a manufacturing method for rolling a titanium-steel composite profile and the titanium-steel composite profile. The manufacturing method comprises the following steps: (1) preparing a steel core material by using carbon steel, preparing a titanium pipe by using titanium or titanium alloy, and reserving a sleeving interference magnitude; (2) heating the titanium pipe, and sleeving the titanium pipe with the steel core material to form a titanium-steel composite blank; (3) wrapping the titanium steel composite blank with a high-temperature-resistant anti-oxidation layer; (4) heating the titanium steel composite blank to a hot rolling temperature; and (5) rolling to obtain the titanium-steel composite profile. By means of the method, the composite blank with the steel core material wrapped by the titanium pipe can be directly rolled into the profile, and the low-cost and high-corrosion-resistance composite profile suitable for mass production is obtained. According to the manufacturing method, bending and welding are not needed, and compared with a steel profile, the surface corrosion resistance of the obtained titanium-steel composite profile is improved, and compared with a titanium profile, the material cost is reduced.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a rolled titanium-steel composite profile and also relates to the titanium-steel composite profile obtained by the manufacturing method, belonging to the technical field of composite metal profile preparation. Background Art

[0002] Profiles are semi-finished products that are close to the final shape. They have the characteristics of high structural efficiency and good mechanical properties. They can be used directly as structural parts without processing or after a small amount of processing. Traditional profiles are made of steel, and their corrosion resistance in marine environments is significantly weaker than that of titanium alloys. Titanium alloys have significant characteristics such as high specific strength, high temperature resistance, and corrosion resistance. They are widely and importantly used in marine engineering, aerospace, chemical industry, equipment manufacturing and other industries. The price of titanium alloys is more than 20 times that of ordinary steel. The existing technology uses titanium alloys and ordinary steel to make titanium-steel composite plate profiles to obtain low-cost, high-corrosion-resistant plates.

[0003] In the Chinese invention with patent number ZL 202110163079.X, a method for preparing a titanium-steel composite plate profile is disclosed. The preparation method includes the following steps: ① Use a bending machine to cold-bend the titanium-steel composite plate into a U-shaped groove; ② Intermittently tear the edges at the corresponding positions of the two U-shaped groove edges, that is, intermittently remove part of the titanium clad layer to expose the base steel plate below the area; ③ Bevel the exposed base steel plate along the 45° direction of the edge; ④ The two U-shaped grooves are opened relative to each other and the edges are butted, and the base steel plate at the torn edge position is welded and the welding slag is polished; ⑤ Titanium bars are attached to the weld position, and the titanium clad layer and titanium bars at the torn edge position are welded with pure titanium welding wire, and the welding slag is polished; ⑥ The remaining untorn butt seams are welded with pure titanium welding wire; ⑦ The profile surface is repaired and sandblasted. The preparation method can obtain a titanium-steel composite plate rectangular tube profile.

[0004] Similarly, the existing methods for obtaining titanium-steel composite profiles are to first obtain titanium-steel composite plate profiles, and then bend, grind, and weld the plate profiles to obtain I-beams, channels, and T-shaped steels. Practice has shown that too many bending times can lead to separation of the titanium layer and the steel layer in the titanium-steel composite plate, cracking of the titanium layer on the outer surface of the chamfer after bending, excessive bending pressure, and bending rebound. In addition, because the weld needs to be ground to remove the local titanium alloy and then weld the steel substrate, the titanium-steel composite profiles obtained by the existing technology are difficult to process, costly, and lack strength. Summary of the invention

[0005] The primary technical problem to be solved by the present invention is to provide a method for manufacturing a rolled titanium-steel composite profile.

[0006] Another technical problem to be solved by the present invention is to provide a titanium-steel composite profile obtained by the above manufacturing method.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] According to a first aspect of an embodiment of the present invention, there is provided a method for manufacturing a rolled titanium-steel composite profile, comprising the following steps:

[0009] Step S1: Use carbon steel to prepare a steel core material with an outer diameter of D1, and use titanium or titanium alloy to prepare a titanium tube with an inner diameter of D2, satisfying D1>D2, and D1=D2+△d; where △d is the reserved interference, satisfying △d≥D2α 2(2) T2-D1α 1(2) T2, and the reserved interference Δd is calculated according to the difference in expansion between the titanium tube and the steel core material at the design temperature; T2 is the heating temperature of the titanium-steel composite billet in step S4; α 1(2) α is the thermal expansion coefficient of the steel core material at temperature T2; 2(2) is the thermal expansion coefficient of the titanium tube at temperature T2;

[0010] Step S2: heating the titanium tube to a temperature T1, so that the inner diameter D2 of the titanium tube expands to D3, satisfying D3>D1 and D3-D1≥d'; d' is the minimum assembly gap between the steel core material and the heated titanium tube; then assembling the steel core material and the heated titanium tube together to obtain the titanium-steel composite billet;

[0011] Step S3: wrapping the titanium steel composite billet with a high temperature resistant and anti-oxidation layer;

[0012] Step S4: heating the titanium-steel composite billet to a temperature T2;

[0013] Step S5: rolling the heated titanium-steel composite billet to obtain a titanium-steel composite profile; wherein the titanium tube and the steel core material are always closely matched during the rolling process to satisfy D1+D1α 1(2) T2≥D2+D2α 2(2) T2.

[0014] Preferably, the step S1 further comprises calculating the outer diameter D1 of the steel core material 1 according to the inner diameter D2 of the titanium tube.

[0015] Preferably, the step S2 further comprises: 2(1) T1-△d≥d', calculate the heating temperature T1 of the titanium tube; where α 2(1) is the thermal expansion coefficient of the titanium tube at temperature T1.

[0016] Preferably, the heating temperature T2 of the titanium-steel composite billet before rolling provided in step S4 is 1420±10°C.

[0017] Preferably, the titanium tube prepared in step S1 is a round tube or a square tube; and the steel core material is a round steel or a square steel of a corresponding shape.

[0018] Preferably, in step S1, the titanium pipe is a straight seam welded pipe made by a pipe production line, and the inner diameter D2 of the pipe is obtained by fixing the inner diameter.

[0019] Preferably, in step S1, the steel core material is sized by cold drawing to obtain a core material outer diameter D1.

[0020] Preferably, the step S2 further comprises the step of welding the ends of the assembled steel core material and the titanium tube.

[0021] According to a second aspect of an embodiment of the present invention, there is provided a titanium-steel composite profile obtained by the above manufacturing method, wherein the titanium-steel composite profile comprises a hot-rolled bar and a hot-rolled profile.

[0022] Compared with the prior art, the manufacturing method of the rolled titanium-steel composite profile provided in the embodiment of the present invention designs the dimensions of the titanium tube and the steel core material so that the inner diameter of the titanium tube is smaller than the outer diameter of the core material and meets the interference required by the design, and then the titanium tube is heated and combined with the steel core material to achieve a tight pressing of the titanium tube and the steel core material. During the hot rolling of the titanium-steel composite billet, the titanium tube and the steel core material are always tightly combined to avoid cracks at the interface of the titanium tube and the steel core material, thereby obtaining a qualified hot-rolled titanium-steel composite profile. This manufacturing method does not require bending and welding, and is suitable for manufacturing hot-rolled bars and hot-rolled profiles of various cross-sectional shapes. The obtained titanium-steel composite profile has improved surface corrosion resistance compared to steel profiles and reduced material costs compared to titanium profiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a titanium-steel composite billet in the first embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of a process flow of rolling a titanium-steel composite profile in the first embodiment of the present invention;

[0025] Figure 3 This is a physical picture of the cracked sample during the trial production process. DETAILED DESCRIPTION

[0026] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The technical concept in the embodiment of the present invention is: use titanium tube 2 to cover steel core material 1 to make titanium steel composite billet, and directly roll the titanium steel composite billet into profile. Specifically, the titanium tube and steel core material are sized and decontaminated, the steel core material 1 is pressed into the titanium tube 2, and the ends are welded to form a titanium steel composite billet. The titanium steel composite billet is subjected to anti-oxidation treatment and heating, and hot-rolled according to the profile hot rolling process to form a titanium steel composite profile.

[0028] In the national standard GB / T8547-2019 "Titanium-Steel Composite Plate", titanium-steel composite plate refers to a metal composite plate that uses explosion or rolling methods to achieve metallurgical bonding between titanium (composite material) and steel (substrate). The use of titanium-steel composite plates to manufacture traditional non-continuous cross-section profiles (such as I-beams and T-shaped steels, etc.) requires grinding to remove local titanium alloys and then welding the steel substrate. The welds of this titanium alloy profile have lost the protection of the titanium alloy, which not only makes the process difficult and costly, but also has insufficient rust resistance and structural strength. The blank of the traditional titanium-steel composite plate is a structure in which multiple layers of sheet materials are bonded to each other, which is suitable for multiple rolling passes with rolling forces in opposite directions. However, the rolling process of the steel section involves reversing rolling, and due to different forces, the interface between the sheet composite material and the substrate cannot be pressed. Specifically, since the hole system for rolling bars and profiles is flat-vertical alternating rolling (or two sets of common rail holes), the initial rough rolling system is generally flat-flat-vertical-flat-vertical, or flat-flat-flat-flat-vertical rolling. The flat rolling of the first few holes causes obvious gaps on the bonding surfaces of the composite materials and the base material on both sides of the rolled piece. This gap that appears on the interface of the rolled piece will inevitably become a permanent defect. This is because when the rolling force or the rolled piece is reversed, due to the effect of cooling water, the temperature of the composite materials on both sides of the rolled piece drops rapidly, and the temperature of the base material drops more slowly, and the gap surface is oxidized to varying degrees, which makes it impossible to press well. At present, there is no precedent for successful hot-rolled titanium steel composite profiles in the industry.

[0029] First embodiment

[0030] The titanium steel composite profile provided in the embodiment of the present invention is formed by continuously rolling the titanium steel composite billet. Figure 1 As shown, the titanium steel composite billet includes a steel core material 1 and a titanium tube material 2. The steel core material 1 is round steel or square steel, and its function is equivalent to the base material in the titanium steel composite plate. The titanium tube material 2 is a titanium alloy or pure titanium tube material, and its function is equivalent to the composite material in the titanium steel composite plate.

[0031] The embodiment of the present invention provides a method for manufacturing a rolled titanium-steel composite profile, which uses a titanium tube 2 to cover a steel core material 1 to form a rod-shaped titanium-steel composite billet with a long straight direction, and then continuously rolls it into a profile. Figure 2 is a process flow chart of the manufacturing method provided by an embodiment of the present invention. Figure 2 As shown, the manufacturing method includes the following steps.

[0032] Step S1: Prepare the core material and the tube for cladding. Among them, the steel core material 1 with an outer diameter of D1 is made of carbon steel, and the titanium tube 2 with an inner diameter of D2 is made of titanium or titanium alloy, satisfying D1>D2, and D1=D2+△d. Among them, △d is the reserved interference, satisfying △d≥D2α 2(2) T2-D1α 1(2) T2, and the reserved interference Δd is calculated according to the difference in expansion between the titanium tube 2 and the steel core material 1 at the design temperature T2. T2 is the heating temperature before the titanium steel composite billet is rolled. 1(2) , α 2(2) are the thermal expansion coefficients of the steel core material 1 and the titanium tube 2 at temperature T2, respectively.

[0033] When the inner diameter D2 of the titanium tube 2 is known, the expansion difference between the steel core material 1 and the titanium tube 2 can be calculated according to the thermal expansion coefficient of the steel core material 1 and the titanium tube 2 at the temperature T2, and the reserved interference △d≥D2α 2(2) T2-D1α 1(2) T2. Then, the outer diameter D1 of the steel core material 1 is calculated based on the inner diameter D2 of the titanium tube 2 and the reserved interference △d. The difference in expansion between titanium or titanium alloy and carbon steel is mainly determined by the expansion at a lower temperature, so the thermal expansion coefficient at the highest temperature is selected from the thermal expansion coefficient table given by the national standard for approximate calculation to simplify the dimensional design process.

[0034] The titanium tube 2 used for cladding can be a round tube or a square tube. According to the shape and size of the steel core material 1, a pure titanium or titanium alloy sheet with a thickness of 2 to 12 mm is used, and a straight seam welded pipe of corresponding specifications is made using a pipe production line to form a titanium tube 2. Then the inner diameter D2 of the titanium tube 2 is determined and made to meet the specified tolerance range. It is worth noting that compared with the forming process of cold bending and welding, the welded pipe process is a high-efficiency production method.

[0035] The steel billet used as the core material is machined or shot blasted and cold drawn (with cold drawing oil) to obtain the outer diameter D1 of the steel core material 1, and the surface is decontaminated. Ensure that the outer diameter (square or round) of the steel core material 1 and the inner diameter of the titanium tube 2 have a certain interference (for example, 0.30-0.40 mm). It is worth noting that the forming methods of the core material steel billet include continuous casting square billet, rectangular billet, round billet or secondary billet square billet, rectangular billet, round billet, etc.

[0036] Step S2: After heating the tube, combine the core material and the tube, weld the interfaces at both ends, and obtain a titanium steel composite billet. The titanium tube 2 is heated to a temperature T1, so that the inner diameter D2 of the titanium tube 2 expands to D3, satisfying D3>D1 and D3-D1≥d', where d' is the minimum assembly gap between the steel core material 1 and the heated titanium tube 2. Then, the steel core material 1 and the heated titanium tube 2 are assembled together to obtain a titanium steel composite billet.

[0037] When D1 and D2 are known, calculate the heating temperature T1 of the titanium tube 2. 2(1) T1-△d≥d',α 2(1) is the thermal expansion coefficient of the titanium tube 2 at temperature T1. When the assembly gap between the steel core material 1 and the heated titanium tube 2 is larger, it is easier to press the steel core material 1 into the titanium tube 2.

[0038] Before assembling the titanium-steel composite billet, the titanium tube 2 is heated to the design temperature T1 (for example, 300-900°C, preferably 750°C) to obtain the shrink-fit expansion. The expansion is greater than the interference between the outer diameter of the core material and the inner diameter of the tube at room temperature. The prepared core material is pressed into the tube with a press, and when cooled to room temperature, the assembled tube and core material form an interference assembly state. It is worth noting that each batch of titanium-steel composite billets must be assembled immediately after the surface of the steel core material 1 and the titanium tube 2 are decontaminated to prevent their surfaces from being contaminated and rusted again. After assembly, the titanium-steel composite billets can be stored for a long time.

[0039] From the above calculation process, it can be seen that at room temperature, the greater the difference between the reserved interference △d between the outer diameter of the steel core material 1 and the inner diameter of the titanium tube 2 relative to the expansion of the steel core material 1 and the titanium tube 2 at temperature T2, the tighter the combination of the steel core material 1 and the titanium tube 2 during the hot rolling process. However, when the reserved interference △d between the outer diameter of the steel core material 1 and the inner diameter of the titanium tube 2 is larger, in order to smoothly press the steel core material 1 into the interior of the titanium tube 2, the titanium tube 2 needs to expand more, that is, the higher the temperature T1 that the titanium tube 2 needs to be heated. Therefore, for economic and safety considerations, the reserved interference △d is not the larger the better, and a compromise design should be made.

[0040] In order to ensure the interface pressing state between the composite material and the core material during the heating process and to prevent the core material and the composite material from sliding relative to each other during the first few rolling passes, the interfaces at both ends are welded. The titanium steel composite billet produced in this way can ensure that the interface between the titanium tube 2 and the steel core material 1 remains in a tight state during the entire rolling process, and always maintains a good state of interface pressing, thereby ensuring the bonding strength of the billet interface.

[0041] It is worth noting that the cross-sectional shapes of the titanium-steel composite billet include round, square and rectangular.

[0042] It should also be noted that the cooling rate of the titanium-steel composite billet after rolling has a significant impact on its microstructure and final performance. In a preferred embodiment of the present invention, under the condition of an induction heating temperature of 750°C to 950°C, the interface bonding of the titanium / steel composite plate is good. In particular, when heat treated at about 850°C (preferably with a fluctuation of no more than 20°C), the interface of the titanium / steel composite plate is straight and uniform in thickness, and the microstructure and mechanical properties are better.

[0043] Step S3: The titanium-steel composite billet is wrapped with a high-temperature resistant and anti-oxidation layer.

[0044] In the process of producing titanium steel composite profiles, in order to prevent the outer surface of the titanium steel composite billet from being oxidized during the heating stage, resulting in unnecessary oxidation loss of the titanium alloy, the titanium steel composite billet must be specially treated before heating. This treatment process includes the following methods:

[0045] First, the outer surface of the titanium steel composite billet can be brushed or soaked with a lubricant, which can form a protective film during heating to reduce the possibility of oxidation.

[0046] Secondly, an anti-oxidation coating can be brushed on the surface of the titanium steel composite billet. After the coating is dry, a layer of glass powder is rolled to enhance the anti-oxidation effect. In addition, placing glass powder on the conical surface of the extrusion die can further provide lubrication and reduce friction and oxidation during the rolling process.

[0047] Finally, the entire titanium-steel composite billet can be completely wrapped with mild steel or copper material with a thickness of 0.6 to 1 mm. This wrapping method can provide more comprehensive protection for the titanium-steel composite billet to prevent oxidation during heating and rolling.

[0048] These high temperature resistant anti-oxidation layer measures are particularly important in the first 7 to 8 passes of rolling, because they can effectively resist oxidation during the rolling process and protect the surface of the titanium steel composite billet. As the rolling process proceeds, the temperature of the billet will gradually decrease and the oxidation reaction will also weaken accordingly. Therefore, in the subsequent rolling process, the surface of the titanium steel composite billet will basically not be affected by oxidation, thus ensuring that the final product has excellent surface quality. Through these carefully designed anti-oxidation measures, titanium steel composite profile products with good surface quality can be produced.

[0049] In a preferred embodiment of the present invention, high temperature resistant ceramic fiber cloth can also be used as the high temperature resistant anti-oxidation layer of the titanium steel composite blank, as described below:

[0050] Ceramic fiber cloth is an ideal choice for high temperature resistant and anti-oxidation layer of titanium steel composite billets due to its excellent high temperature resistance and chemical stability. This material can withstand high temperatures of up to 1000℃ to 1400℃, depending on the type of fiber and the production process. Due to its low thermal conductivity, ceramic fiber cloth performs well in isolating heat and reducing heat loss, while protecting titanium steel composite billets from high temperatures.

[0051] During the wrapping process, first ensure that the surface of the titanium steel composite blank is clean and oil-free to ensure good contact between the fiber cloth and the blank. Next, cut the ceramic fiber cloth of appropriate size according to the size of the blank and wrap it tightly on the outer surface of the titanium steel composite blank, ensuring that there are no gaps to prevent oxygen penetration. In order to fix the fiber cloth, high-temperature resistant bands or clamps can be used to prevent displacement or falling off during heating and rolling.

[0052] During the heating and rolling process, the ceramic fiber cloth can not only protect the titanium steel composite billet from oxidation, but also reduce heat loss. In addition, it can reduce the friction between the billet and the roller, reduce wear, and protect the billet surface from oxidation. After each heating and rolling, the condition of the ceramic fiber cloth should be checked to see if there is any wear or damage, and the damaged fiber cloth should be replaced in time to ensure continuous anti-oxidation protection.

[0053] Step S4: rolling and heating the titanium steel composite billet to a temperature T2, wherein the temperature T2 is 1420±10°C.

[0054] In order to ensure good lamination of the composite interface, the furnace temperature of the titanium steel composite billet is slightly higher than the process temperature of the traditional carbon steel profile, which has a better effect. The melting point of titanium alloy is relatively high (1668±4℃), and the titanium tube 2 covered on the outer layer can well protect the internal steel core material 1. Because the direct scouring of the flame can cause micro-melting on the surface of the steel core material 1 in contact with the titanium tube 2, the furnace temperature T2 of the titanium steel composite billet is increased to 1420±10℃, which can provide better interface lamination conditions.

[0055] It is worth noting that the initial rolling temperature of ferrous metal hot rolling is generally 1100-1150℃. At this time, the metallographic structure of the steel is austenite, and its rolling deformation resistance is below 0.5MPa, and it has good ductility. According to the test, when the furnace temperature is 1100℃, the deformation resistance of the titanium steel composite rolled piece is large and the ductility of the composite material is poor. The composite material and the core material cannot be rolled together, and the composite material appears to have multiple horizontal cracks or all cracks, such as Figure 3 When the initial rolling temperature is increased to 1350℃, micro cracks visible to the naked eye still appear. When the initial rolling temperature is increased to 1420±10℃, the cracking of the composite material is completely eliminated, and a stable ideal composite state is obtained.

[0056] Step S5: rolling the titanium steel composite billet into a titanium steel composite profile. The titanium tube 2 and the steel core material 1 are always closely matched during the rolling process, satisfying D1+D1α 1(2) T2≥D2+D2α 2(2) T2.

[0057] Rolling generally adopts 12 to 13 rolling passes, and the cross-sectional area of ​​the titanium steel composite billet is used as a reference to control the deformation of each rolling pass. Among them, the hole design is based on the characteristics of thermal deformation. When the deformation resistance is large, a small reduction, small deformation, and multiple rolling methods are adopted, and the deformation of each pass is less than 28%. The bite angle of the rolled piece is 30% or less than the bite angle of ordinary steel, which can ensure that the composite interface of the titanium steel composite profile is firmly integrated. Since the process of rolling profiles of titanium steel composite billets is similar to the rolling process in the prior art, it will not be repeated here.

[0058] It is worth noting that the profile specifications rolled by the manufacturing method provided in the embodiment of the present invention include but are not limited to bars (GB / T702), flats (GB / T704), I-beams (GB / T706), channels (GB / T707), ribbed steel bars (GB / T1499), angle steels (GB / T9787), bulb flat steels (GB / T9945), T-shaped steels (GB / T 11263) and H-shaped steels (YB3301), as well as steel for guardrails and other non-standard special-shaped steels. For example, flat steel with a thickness of 4 mm or more and a width of 15 mm or more, round steel with a diameter of φ9 mm or more, angle steel with a thickness of 30 mm×3 mm or more, unequal angle steel with a waist thickness of 3 mm or more, construction threaded steel with a diameter of φ10 mm or more, and cross-sectional area of ​​100 mm. 2 And above steel and non-standard special-shaped steel.

[0059] The thickness of the titanium alloy layer of the actual hot-rolled titanium steel composite profile product is greater than 1 mm. After performance testing, the bonding degree and bonding strength of the composite material interface meet the requirements of GB / T6396-2008 "Test methods for mechanical and process properties of composite steel plates" regarding bonding degree test (item 8) and bonding test (item 9).

[0060] Second embodiment

[0061] The embodiment of the present invention provides a titanium steel composite profile, which is obtained by the manufacturing method of the first embodiment. The profile specifications include but are not limited to bars (GB / T702), flats (GB / T704), I-beams (GB / T706), channels (GB / T707), ribbed steel bars (GB / T 1499), angle steels (GB / T9787), bulb flat steels (GB / T9945), T-shaped steels (GB / T 11263) and H-shaped steels (YB3301), as well as guardrail steels and other non-standard special-shaped steels.

[0062] In summary, the embodiments of the present invention provide a method for manufacturing a rolled titanium-steel composite profile and a titanium-steel composite profile. A titanium-steel composite billet is made by coating a steel core material with a titanium tube, and the titanium-steel composite billet is directly rolled into a profile, thereby avoiding cracks at the interface between the titanium tube and the steel core material, thereby obtaining a qualified hot-rolled titanium-steel composite profile. The titanium-steel composite profile uses the metallic inertness of the titanium composite material to protect the internal steel substrate from corrosion and oxidation, and the steel substrate supports the profile's force-bearing structure with a low-cost material, thereby obtaining a low-cost, highly corrosion-resistant composite profile suitable for mass production. This manufacturing method does not require bending and welding.

[0063] It should be noted that the above embodiments are only examples, and the technical solutions of the various embodiments can be combined, all within the protection scope of the present invention.

[0064] It should be noted that the term "formation" in the present invention means that it can be obtained by one of a variety of processes and is not limited to the processes listed in the embodiments. The order of steps in the present invention can be changed according to actual needs, the order of steps can be changed, and serial processing can also be changed to parallel processing, which is not limited to the order of steps listed in the embodiments.

[0065] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0066] The above is a detailed description of the manufacturing method of the rolled titanium steel composite profile and the titanium steel composite profile provided by the present invention. For those skilled in the art, any obvious changes made to it without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and will bear the corresponding legal liability.

Claims

1. A method for manufacturing a rolled titanium steel composite profile, characterized in that The steps include: Step S1: Use carbon steel to prepare a steel core material with an outer diameter of D1, and use titanium or titanium alloy to prepare a titanium tube with an inner diameter of D2, satisfying D1>D2, and D1=D2+△d; wherein △d is a reserved interference, satisfying △d≥D2α 2(2) T2-D1α 1(2) T2, and the reserved interference Δd is calculated according to the difference in expansion between the titanium tube and the steel core material at the design temperature; T2 is the heating temperature of the titanium-steel composite billet in step S4; α 1(2) α is the thermal expansion coefficient of the steel core material at temperature T2; 2(2) is the thermal expansion coefficient of the titanium tube at temperature T2; Step S2: heating the titanium tube to a temperature T1, so that the inner diameter D2 of the titanium tube expands to D3, satisfying D3>D1 and D3-D1≥d'; d' is the minimum assembly gap between the steel core material and the heated titanium tube; then assembling the steel core material and the heated titanium tube together to obtain the titanium-steel composite billet; Step S3: wrapping the titanium steel composite billet with a high temperature resistant and anti-oxidation layer; Step S4: heating the titanium-steel composite billet to a temperature T2; Step S5: rolling the heated titanium-steel composite billet to obtain a titanium-steel composite profile; wherein the titanium tube and the steel core material are always closely matched during the rolling process to satisfy D1+D1α 1(2) T2≥D2+D2α 2(2) T2.

2. The manufacturing method according to claim 1, characterized in that: The step S1 further includes calculating the outer diameter D1 of the steel core material 1 according to the inner diameter D2 of the titanium tube.

3. The manufacturing method according to claim 1, characterized in that: The step S2 also includes calculating the formula D2α 2(1) T1-△d≥d', calculate the heating temperature T1 of the titanium tube; where α 2(1) is the thermal expansion coefficient of the titanium tube at temperature T1.

4. The manufacturing method according to any one of claims 1 to 3, characterized in that: The heating temperature T2 of the titanium-steel composite billet before rolling provided in step S4 is 1420±10°C.

5. The manufacturing method according to any one of claims 1 to 3, characterized in that: The titanium tube prepared in step S1 is a round tube or a square tube; the steel core material is a round steel or a square steel of a corresponding shape.

6. The manufacturing method according to any one of claims 1 to 3, characterized in that: In the step S1, the titanium pipe is a straight seam welded pipe made by a pipe production line, and the inner diameter D2 of the pipe is obtained by determining the inner diameter.

7. The manufacturing method according to any one of claims 1 to 3, characterized in that: In the step S1, the steel core material is sized by cold drawing to obtain a core material outer diameter D1.

8. The manufacturing method according to any one of claims 1 to 3, characterized in that: The step S2 also includes the step of welding the ends of the assembled steel core material and the titanium tube.

9. A titanium steel composite profile obtained by the manufacturing method according to any one of claims 1 to 8, characterized in that: The titanium steel composite profile includes hot-rolled bars and hot-rolled profiles.

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