A method for preparing titanium / steel composite plates by hot rolling in an atmospheric environment

Abstract

The present invention provides a method for hot-rolling titanium / steel composite plates under an atmospheric environment, belonging to the technical field of preparation of metal laminated composites. The method includes mechanically grinding the surfaces to be compounded of the titanium plate and the steel plate, then laminating the titanium plate and the steel plate to form a billet, wrapping both sides with copper foil, feeding it into a high-frequency induction heating coil for on-line heating, controlling the temperature at the titanium / steel interface to be 800-1000 °C, and finally obtaining the titanium / steel composite plate by single-pass hot rolling. This method does not require vacuum electron beam welding, can prepare titanium / steel composite plates with high interface bonding quality by hot rolling under an atmospheric environment, and has the advantages of low production cost, simple process, and easy industrial promotion.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of metal laminated composites, and more specifically, to a method for hot-rolling the preparation of titanium / steel composite plates under an atmospheric environment. Background Art

[0002] Titanium / steel composite plates have the advantages of excellent corrosion resistance of titanium and high strength and low cost of steel, and are widely used in fields such as petrochemical industry, architectural decoration, and ocean engineering. The preparation methods of titanium / steel composite plates mainly include explosive bonding method and hot-rolling bonding method. The explosive bonding method uses the impact force of explosion to bond titanium plates and steel plates together. The process is simple, and the interface bonding strength of the prepared titanium / steel composite plate is high. However, this method has problems such as environmental pollution and difficulty in continuous production. The hot-rolling bonding method is to first perform surface treatment on titanium plates and steel plates, then group the blanks by vacuum electron beam welding or small-hole vacuum pumping methods to ensure the interface vacuum, and finally perform multi-pass hot rolling to achieve the composite of titanium plates and steel plates. The hot-rolling bonding method has the advantages of high production efficiency and the ability to produce wide-width titanium / steel composite plates, and has become the main method for industrial preparation of titanium / steel composite plates. However, this method requires a vacuum environment at the titanium / steel interface to avoid oxidation damage to the interface bonding quality, has high requirements for equipment, and the process is cumbersome.

[0003] CN1** discloses a method for preparing a titanium-steel composite plate, which prepares a titanium / steel composite plate with high bonding performance through processes such as blank preparation, surface treatment, application of release agent, symmetric grouping of blanks, electron beam sealing welding, heating, rolling, straightening, and cutting and splitting of plates. CN1** discloses a method for preparing a titanium-steel composite plate, which is to perform surface treatment on titanium billets and steel billets, then apply a coating on the surface of the titanium billets and perform room-temperature drying; stack the surface-treated and coated titanium billets pairwise and correctly, place a steel billet in the middle, and symmetrically group the blanks; weld and seal the periphery of the combined blanks and perform vacuum pumping; place the composite blank in a heating furnace for heat treatment, then perform multi-pass rolling, and after rolling, the composite blank is air-cooled, and edge trimming and tension leveling treatment are performed to obtain a titanium / steel composite plate. Both of the above two patent documents require vacuum treatment for the titanium / steel grouped blanks before hot rolling.

[0004] Intermetallic compounds such as TiC, FeTi, and Fe2Ti are generated during the hot rolling of the titanium / steel composite plate interface. The C content in steel is low, so the generation amount of TiC at the titanium / steel interface is small, and the influence on the interface bonding quality is small. When the hot rolling temperature exceeds 882 °C, titanium will undergo β-Ti phase transformation, and FeTi and Fe2Ti intermetallic compounds, that is, Fe-Ti phase, will be generated at the titanium / steel interface. The Fe-Ti phase will seriously damage the interface bonding quality. To avoid the generation of the Fe-Ti phase at the titanium / steel interface, the hot rolling temperature of the titanium / steel composite plate is generally lower than 882 °C. However, at lower temperatures, the deformation resistance of titanium and steel is large, and the hot rolling reduction ratio is small, which is not conducive to improving the interface bonding quality.

[0005] Traditional hot-rolling cladding requires a vacuum environment at the titanium / steel interface, placing high demands on equipment. Furthermore, high-temperature hot rolling can generate Fe-Ti phases at the titanium / steel interface, compromising the interfacial bonding strength. To address these two challenges, developing a method for preparing titanium / steel clad plates by hot rolling in an atmospheric environment while simultaneously controlling the formation of intermetallic compounds at the interface is of great significance. Summary of the Invention

[0006] In view of the above technical problems, a method for preparing titanium / steel composite plates by hot rolling in an atmospheric environment is provided to solve the problems that the traditional hot rolling composite method requires a vacuum environment at the interface and the Fe-Ti phase is easily generated at the interface.

[0007] The technical means adopted in the present invention are as follows:

[0008] A method for preparing a titanium / steel composite plate by hot rolling in an atmospheric environment comprises:

[0009] S1. Mechanically grind the surfaces of the titanium plate and the steel plate to be composited using a grinding wheel or a diamond grinding wheel to obtain a clean and rough composite surface; the titanium plate is made of pure titanium, and the type can be but not limited to TA1, TA2, TA3 or TA10; the steel plate is made of low carbon steel, and the type can be but not limited to Q235, Q275 or 20#;

[0010] S2, after the titanium plate and steel plate are stacked and assembled, both sides are covered with copper foil, and then sent to a high-frequency induction heating coil for online heating. By adjusting the induction current and coil length, the surface temperature of the titanium plate reaches 800-882°C and the surface temperature of the steel plate reaches 912-1000°C when the assembled blank passes through the induction heating coil;

[0011] S3. A titanium / steel composite plate is obtained by hot rolling in a single pass, with a hot rolling reduction of 15%-35%. The interface of the obtained titanium / steel composite plate has no Fe-Ti phase and an interface bonding strength greater than 200 MPa.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) The preparation method of the titanium / steel composite plate provided by the present invention includes three steps: surface mechanical grinding → induction heating → hot rolling composite. Compared with the traditional hot rolling composite method, it has the advantages of simple process, short flow, low equipment requirements, high production efficiency, and easy industrial promotion.

[0014] (2) The present invention utilizes the fast induction heating speed (less than 10s) and the copper foil coating to avoid oxidation of the titanium / steel interface, eliminating the traditional interface welding vacuum treatment, and hot rolling can be used to prepare titanium / steel composite plates in an atmospheric environment.

[0015] (3) The present invention utilizes the skin effect of induction heating. During heating, the temperature at the titanium / steel interface is higher than that inside the sheet. When the interface reaches the hot rolling temperature, the temperature inside the sheet is still relatively low. While the metal at the interface softens, the inside of the sheet still maintains a relatively high strength. The softening of the metal at the interface is conducive to the plastic flow of the interface metal during rolling, and the high strength maintained inside the sheet is conducive to the transmission of the rolling pressure, increasing the interface force. By combining these two aspects, it is possible to reduce the hot rolling reduction while improving the interface bonding quality.

[0016] (4) The present invention utilizes the characteristic that the heating rate of the titanium sheet is slower than that of the steel sheet during induction heating, enabling the temperature of the titanium sheet to be <882 °C while the temperature of the steel sheet is >912 °C under this condition. At this time, the titanium sheet is still α-Ti and does not undergo the α-β Ti phase transformation, avoiding the formation of the Fe-Ti phase at the interface and damaging the interface bonding quality. However, the steel sheet undergoes the γ-Fe phase transformation, which is conducive to the plastic flow of the interface metal during rolling and improves the interface bonding quality.

[0017] Based on the above reasons, the present invention can be widely promoted in the fields such as the preparation of metal laminated composites. Specific Embodiments

[0018] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will describe the present invention in detail with reference to the embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way constitutes a limitation to the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0019] The present invention provides a method for hot rolling titanium / steel composite plates under an atmospheric environment, including:

[0020] S1. Mechanically polish the surfaces to be composite of the titanium sheet and the steel sheet using a grinding wheel or a diamond grinding wheel to obtain clean and rough surfaces to be composite. The material of the titanium sheet is pure titanium, and the model can be but is not limited to one of TA1, TA2, TA3 or TA10; the material of the steel sheet is low-carbon steel, and the model can be but is not limited to one of Q235, Q275 or 20#.

[0021] S2. Stack the titanium sheet and the steel sheet to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the induction heating coil, the surface temperature of the titanium sheet reaches 800 - 882 °C, and the surface temperature of the steel sheet reaches 912 - 1000 °C.

[0022] S3. Obtain a titanium / steel composite plate by single-pass hot rolling, with a hot rolling reduction of 15%-35%; there is no Fe-Ti phase at the interface of the obtained titanium / steel composite plate, and the interface bonding strength > 200 MPa.

[0023] Example 1

[0024] A method for preparing a titanium / steel composite plate by hot rolling in an atmospheric environment. The cladding material is TA2 pure titanium, the initial thickness of the titanium plate is 2.0 mm, the base material is Q235 low-carbon steel, and the initial thickness of the steel plate is 5.0 mm. First, grind the surface of the plates transversely with a grinding wheel to remove pollutants such as oxidation, dust, and water vapor on the surfaces to be composite. Then stack the titanium plate and the steel plate to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the coil, the surface temperature of the titanium reaches 850 °C and the surface temperature of the steel plate reaches 920 °C. Finally, send the billet into a rolling mill for single-pass hot rolling, with a hot rolling reduction of 30%. There is no Fe-Ti phase generated at the interface of the obtained titanium / steel composite plate, and the interface bonding strength is 230 MPa.

[0025] Example 2

[0026] A method for preparing a titanium / steel composite plate by hot rolling in an atmospheric environment. The cladding material is TA1 pure titanium, the initial thickness of the titanium plate is 2.0 mm, the base material is Q235 low-carbon steel, and the initial thickness of the steel plate is 4.0 mm. First, grind the surface of the plates transversely with a grinding wheel to remove pollutants such as oxidation, dust, and water vapor on the surfaces to be composite. Then stack the titanium plate and the steel plate to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the coil, the surface temperature of the titanium reaches 825 °C and the surface temperature of the steel plate reaches 920 °C. Finally, send the billet into a rolling mill for single-pass hot rolling, with a hot rolling reduction of 25%. There is no Fe-Ti phase generated at the interface of the obtained titanium / steel composite plate, and the interface bonding strength is 236 MPa.

[0027] Example 3

[0028] A method for hot-rolling the titanium / steel composite plate in an atmospheric environment. The clad material is TA2 pure titanium, the initial thickness of the titanium plate is 1.0 mm, the base material is 20# steel, and the initial thickness of the steel plate is 4.0 mm. First, use a diamond grinding wheel to transversely grind the surface of the plate to remove pollutants such as oxidation, dust, and water vapor on the surface to be composite. Then, stack the titanium plate and the steel plate to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the coil, the surface temperature of the titanium reaches 860 °C, and the surface temperature of the steel plate reaches 950 °C. Finally, send the billet into a rolling mill for single-pass hot rolling, with a hot rolling reduction of 20%. The interface of the obtained titanium / steel composite plate does not generate Fe-Ti phase, and the interface bonding strength is 224 MPa.

[0029] Example 4

[0030] A method for hot-rolling the titanium / steel composite plate in an atmospheric environment. The clad material is TA1 pure titanium, the initial thickness of the titanium plate is 1.0 mm, the base material is Q235 steel, and the initial thickness of the steel plate is 2.0 mm. First, use a diamond grinding wheel to transversely grind the surface of the plate to remove pollutants such as oxidation, dust, and water vapor on the surface to be composite. Then, stack the titanium plate and the steel plate to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the coil, the surface temperature of the titanium reaches 800 °C, and the surface temperature of the steel plate reaches 912 °C. Finally, send the billet into a rolling mill for single-pass hot rolling, with a hot rolling reduction of 15%. The interface of the obtained titanium / steel composite plate does not generate Fe-Ti phase, and the interface bonding strength is 215 MPa.

[0031] Example 5

[0032] A method for hot-rolling the titanium / steel composite plate in an atmospheric environment. The clad material is TA1 pure titanium, the initial thickness of the titanium plate is 3.0 mm, the base material is 20# steel, and the initial thickness of the steel plate is 7.0 mm. First, use a diamond grinding wheel to transversely grind the surface of the plate to remove pollutants such as oxidation, dust, and water vapor on the surface to be composite. Then, stack the titanium plate and the steel plate to form a billet, wrap both sides with copper foil, and send it into a high-frequency induction heating coil for on-line heating. By adjusting the magnitude of the induction current and the length of the coil, when the billet passes through the coil, the surface temperature of the titanium reaches 882 °C, and the surface temperature of the steel plate reaches 1000 °C. Finally, send the billet into a rolling mill for single-pass hot rolling, with a hot rolling reduction of 35%. The interface of the obtained titanium / steel composite plate does not generate Fe-Ti phase, and the interface bonding strength is 234 MPa.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements 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 preparing titanium / steel composite plates by hot rolling under atmospheric conditions, characterized in that: include: S1. Mechanically grinding the surfaces of the titanium plate and the steel plate to be composited to obtain a clean and rough composite surface; S2, after the titanium plate and the steel plate are stacked and assembled, both sides are covered with copper foil, and then sent to the induction heating coil for online heating. By adjusting the induction current and the coil length, the surface temperature of the titanium plate reaches 800-882°C and the surface temperature of the steel plate reaches 912-1000°C when the assembled billet passes through the induction heating coil; S3. A titanium / steel composite plate is obtained by single-pass hot rolling. The interface of the titanium / steel composite plate has no Fe-Ti phase and the interface bonding strength is greater than 200 MPa.

2. The method for preparing titanium / steel composite plates by hot rolling under atmospheric conditions according to claim 1, characterized in that: In step S1, the titanium plate is made of pure titanium, and its model is one of TA1, TA2, TA3 or TA10.

3. The method for preparing titanium / steel composite plates by hot rolling under atmospheric conditions according to claim 1, characterized in that: In step S1, the steel plate material is low carbon steel, and the model is one of Q235, Q275 or 20#.

4. The method for preparing titanium / steel composite plates by hot rolling under atmospheric conditions according to claim 1, characterized in that: In step S3, the hot rolling reduction is 15%-35%.

5. The method for preparing titanium / steel composite plates by hot rolling under atmospheric conditions according to claim 1, characterized in that: In the step S1, mechanical grinding is performed using a grinding wheel or a diamond grinding wheel.