A rolling process for a titanium-steel clad plate

Abstract

The application provides a rolling process of a titanium-steel composite medium plate and relates to the technical field of composite plate preparation. The application improves the combination capacity of a transition layer and a base layer and a composite layer and improves the mechanical properties of the composite plate by using a vacuum welding process, a multi-pass hot pressing process and a specific transition layer metal.

Description

Technical Field

[0001] This invention relates to the field of composite plate preparation technology, and in particular to a rolling process for titanium-steel composite medium-thick plates. Background Technology

[0002] Titanium-steel composite plates integrate the excellent corrosion resistance of titanium alloys with the strength and toughness of steel, and have been widely used in energy, petroleum, chemical, marine, and mining industries. Currently, the main production methods for titanium-steel composite plates are explosive bonding, diffusion bonding, explosive bonding rolling, and rolling bonding. Explosive bonding is the most commonly used method, but explosive welding and rolling involves complex processes, many factors affecting the bonding strength of the composite plate, and it also consumes a lot of energy, pollutes the environment, and has a relatively low yield.

[0003] Therefore, rolling composite methods are gradually replacing explosive composite methods for the preparation of titanium-steel composite plates. However, due to the low solid solubility between titanium and iron, brittle phases such as TiC, FeTi, and Fe2Ti easily form at the interface when titanium and steel are directly composited, impairing the bonding performance. Simultaneously, the rolling process of titanium-steel composite plates causes significant plastic elongation deformation at the bonding interface, which greatly affects the distribution and morphology of the interface compounds. How to improve the rolling composite process to prepare titanium-steel composite medium-thick plates with uniform distribution of interface compounds, good interfacial composite performance, and high bonding strength is one of the technical problems that needs to be solved. Summary of the Invention

[0004] This invention overcomes the problems existing in the current rolling composite method for preparing titanium-steel composite medium-thick plates by combining a specific ratio of transition layer metal powder with vacuum welding, heat treatment, and multi-pass hot pressing. This results in a uniform distribution of the composite interface compound morphology, good interfacial composite performance, and improved mechanical properties of the composite plate.

[0005] The rolling process of the titanium-steel composite medium-thick plate of the present invention includes the following steps:

[0006] (1) Before assembly, the base plate and composite plate are surface treated to remove oil and oxide layer;

[0007] (2) Heat treatment is performed after vacuum welding of the assembled billet;

[0008] (3) After heating, perform multiple hot rolling passes, and after hot rolling, air cool to room temperature;

[0009] (4) After edge and surface trimming of the composite plate, a titanium-steel composite medium-thick plate is obtained.

[0010] Further, the chemical composition of the base plate in step (1) by weight percentage includes: C 0.19% to 0.6%, Si 0.18% to 0.3%, Mn 0.15% to 1.5%, Als 0.017% to 0.027%, Ca 0.001% to 0.0025%, P ≤ 0.02%, S ≤ 0.005%, with the balance being Fe and unavoidable impurities.

[0011] Further, the chemical composition of the composite board in step (1) by weight percentage includes: Fe 0.03% to 0.25%, O 0.15% to 0.25%, C 0.02% to 0.05%, N 0.01% to 0.05%, H 0.001% to 0.012%, with the balance being Ti and unavoidable impurities.

[0012] Furthermore, in step (2), the blanks are arranged from top to bottom as composite plate, transition layer, and base plate.

[0013] Furthermore, the transition layer is composed of transition layer metal powder, which, by weight percentage, comprises: Cu 30%–40%, Zn 15%–30%, Ni 20%–40%, and Nb 10%–20%, with the sum of the weight percentages of the above raw materials being 100%.

[0014] Furthermore, the thickness of the transition layer is 1–5 mm.

[0015] Furthermore, in step (2), the vacuum degree of vacuum welding is 1.0 × 10⁻⁶. -2 ~2×10 -2 Pa.

[0016] Furthermore, in step (2), the heat treatment temperature is 1150℃~1200℃, and the heat treatment holding time is 30~50min.

[0017] Furthermore, in step (3), the initial rolling temperature is 1100℃~1150℃, the final rolling temperature is 900℃~1000℃, the number of hot rolling passes is 5~8, and the total rolling reduction is 78%~85%.

[0018] Furthermore, in step (3), the thickness of the post-rolling transition layer is 0.1 to 0.25 mm.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0020] This invention utilizes a vacuum welding process to reduce oxidation at the bonding interface during heating, thus preventing decarburization. Simultaneously, the Fe and coating metal in the matrix exhibit significant diffusion within the solid solution, with ferrite and pearlite uniformly distributed at the transition layer interface. The interface is clean, free of granular or streak-like impurities, resulting in a uniformly distributed composite material structure. There are no significant differences in microstructure and mechanical properties between the periphery and the center of the material. Finally, this invention employs a multi-pass rolling process to refine the recrystallized grains and improve the bonding strength between the transition layer, the base layer, and the composite layer, thereby enhancing the mechanical properties of the material. Detailed Implementation

[0021] The technical solution provided by the present invention will be further described below with reference to the embodiments.

[0022] Example 1

[0023] A rolling process for titanium-steel composite medium-thick plates includes the following steps:

[0024] (1) Before assembly, the base plate and composite plate are surface treated to remove oil and oxide layer;

[0025] The chemical composition of the base plate, by weight percentage, is: C 0.25%, Si 0.2%, Mn 0.6%, Als 0.02%, Ca 0.005%, P≤0.02%, S≤0.005%, with the balance being Fe and unavoidable impurities; the chemical composition of the composite plate, by weight percentage, is: Fe 0.15%, O 0.2%, C 0.03%, N 0.03%, H 0.1%, with the balance being Ti and unavoidable impurities;

[0026] (2) Assemble the blanks in the following order from top to bottom: composite board, transition layer, and base layer board, under a vacuum of 2×10⁻⁶. -2 Under the condition of Pa, the blank is sealed by vacuum welding and then heat treated. The heat treatment temperature is 1150℃ and the heat treatment holding time is 45min.

[0027] The transition layer is composed of Cu 40%, Zn 25%, Ni 20%, and Nb 15% by weight percentage.

[0028] The thickness of the transition layer is 2 mm.

[0029] (3) After heating, 8 passes of hot rolling are performed, with an initial rolling temperature of 1150℃, a final rolling temperature of 960℃, a total rolling reduction of 83%, and a transition layer thickness of 0.12mm. After hot rolling, the material is air-cooled to room temperature.

[0030] (4) After edge and surface trimming of the composite plate, a titanium-steel composite medium-thick plate is obtained.

[0031] Example 2

[0032] A rolling process for titanium-steel composite medium-thick plates includes the following steps:

[0033] (1) Before assembly, the base plate and composite plate are surface treated to remove oil and oxide layer;

[0034] The chemical composition of the base plate, by weight percentage, is: C 0.19%, Si 0.18%, Mn 0.15%, Al 0.017%, Ca 0.0025%, P≤0.02%, S≤0.005%, with the balance being Fe and unavoidable impurities; the chemical composition of the composite plate, by weight percentage, is: Fe 0.03%, O 0.25%, C 0.05%, N 0.01%, H 0.012%, with the balance being Ti and unavoidable impurities.

[0035] (2) Assemble the blanks in the following order from top to bottom: composite board, transition layer, and base layer board, under a vacuum of 2×10⁻⁶. -2 Under the condition of Pa, the blank is sealed by vacuum welding and then heat treated. The heat treatment temperature is 1200℃ and the heat treatment holding time is 30min.

[0036] The transition layer is composed of Cu 30%, Zn 30%, Ni 20%, and Nb 20% by weight percentage.

[0037] The thickness of the transition layer is 3 mm.

[0038] (3) After heating, five hot rolling passes are performed, with an initial rolling temperature of 1150℃, a final rolling temperature of 1000℃, a total rolling reduction of 78%, and a transition layer thickness of 0.2mm. After hot rolling, the material is air-cooled to room temperature.

[0039] (4) After edge and surface trimming of the composite plate, a titanium-steel composite medium-thick plate is obtained.

[0040] Example 3

[0041] A rolling process for titanium-steel composite medium-thick plates includes the following steps:

[0042] (1) Before assembly, the base plate and composite plate are surface treated to remove oil and oxide layer;

[0043] The chemical composition of the base plate, by weight percentage, is: C 0.6%, Si 0.3%, Mn 0.15%, Als 0.027%, Ca 0.001%, P≤0.02%, S≤0.005%, with the balance being Fe and unavoidable impurities; the chemical composition of the composite plate, by weight percentage, is: Fe 0.25%, O 0.15%, C 0.02%, N 0.05%, H 0.001%, with the balance being Ti and unavoidable impurities.

[0044] (2) Assemble the blanks in the following order from top to bottom: composite board, transition layer, and base layer board, under a vacuum of 2×10⁻⁶. -2 Under the condition of Pa, the blank is sealed by vacuum welding and then heat treated. The heat treatment temperature is 1180℃ and the heat treatment holding time is 40min.

[0045] The transition layer is composed of Cu 30%, Zn 15%, Ni 35%, and Nb 20% by weight percentage.

[0046] The thickness of the transition layer is 5 mm.

[0047] (3) After heating, hot rolling is carried out in 5 to 8 passes, with the initial rolling temperature being 1100℃ to 1150℃, the final rolling temperature being 900℃ to 1000℃, the number of hot rolling passes being 5 to 8, the total rolling reduction being 78% to 85%, the thickness of the transition layer after rolling being 0.25mm, and the hot rolling being completed and then air-cooled to room temperature.

[0048] (4) After edge and surface trimming of the composite plate, a titanium-steel composite medium-thick plate is obtained.

[0049] Comparative Example 1

[0050] Same as Example 1, except that the transition layer is composed of Cu 55%, Zn 25%, and Ni 20% by weight percentage.

[0051] Comparative Example 2

[0052] Same as Example 1, except that the transition layer is composed of Cu 50%, Zn 30%, and Nb 20% by weight percentage.

[0053] Comparative Example 3

[0054] Same as Example 1, except that the transition layer is composed of 60% Cu, 20% Ni, and 20% Nb by weight percentage.

[0055] Comparative Example 4

[0056] Same as Example 1, except that the transition layer is Cu.

[0057] Test Example 1

[0058] The microstructure of the interface between the composite plates of Example 1 and Comparative Examples 1-4 was observed by SEM, and the results are as follows:

[0059] Serial Number Combining interface microstructure Example 1 Ferrite and pearlite are evenly distributed, the interface is clean, and no impurities are present. Comparative Example 1 The ferrite and pearlite are unevenly distributed, and a small amount of particulate impurities are present. Comparative Example 2 The ferrite and pearlite are unevenly distributed, and a small amount of particulate impurities are present. Comparative Example 3 The ferrite and pearlite are unevenly distributed, and a small amount of particulate impurities are present. Comparative Example 4 The ferrite and pearlite are unevenly distributed, and a small number of strip-shaped impurities appear.

[0060] It is evident that the selection, composition, and proportion of the transition layer metal have a significant impact on the distribution of ferrite and pearlite and the formation of impurities in the microstructure of the bonding interface.

[0061] Comparative Example 5

[0062] Same as Example 1, except that only a single-pass rolling process is performed.

[0063] Comparative Example 6

[0064] Same as Example 1, except that only two-pass rolling is performed.

[0065] Comparative Example 7

[0066] Same as Example 1, except that three rolling passes are performed.

[0067] Test Example 2

[0068] The mechanical properties of the composite plates prepared in Example 1 and Comparative Examples 5-7 were tested according to GB / T 6396-2008 "Test Methods for Mechanical and Technological Properties of Composite Steel Plates" and GB / T 8547-2006 "Titanium-Steel Composite Plates". The results are as follows:

[0069] Serial Number Tensile strength (MPa) Yield strength (MPa) Example 1 603 455 Comparative Example 5 482 386 Comparative Example 6 522 410 Comparative Example 7 554 432

[0070] It is evident that the multi-pass hot rolling process employed in this application significantly improves the mechanical properties of the composite plate.

[0071] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A rolling process of a titanium-steel clad plate, characterized in that, The method comprises the following steps: (1) surface treatment of base plate and composite plate before assembly, removing oil stains and oxide layer; (2) vacuum welding and sealing assembly, and then heat treatment; (3) multi-pass hot rolling after heating, and air cooling to room temperature after hot rolling; (4) titanium-steel composite plate is obtained after edge and surface finishing of the composite plate; The assembly is composed of composite plate, transition layer and base plate from top to bottom; The transition layer is composed of transition layer metal powder, and the transition layer comprises, by weight percentage, Cu 30%-40%, Zn 15%-30%, Ni 20%-40% and Nb 10%-20%, and the sum of the weight percentages of the above raw materials is 100%. The thickness of the transition layer after rolling is 0.1-0.25 mm.

2. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, The chemical composition of the base plate in step (1) comprises, by weight percentage, C 0.19%-0.6%, Si 0.18%-0.3%, Mn 0.15%-1.5%, Als 0.017%-0.027%, Ca 0.001%-0.0025%, P≤0.02%, S≤0.005%, and the balance is Fe and inevitable impurities.

3. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, The chemical composition of the composite plate in step (1) comprises, by weight percentage, Fe 0.03%-0.25%, O 0.15%-0.25%, C 0.02%-0.05%, N 0.01%-0.05%, H 0.001%-0.012%, and the balance is Ti and inevitable impurities.

4. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, The thickness of the transition layer is 1-5 mm.

5. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, In step (2), the vacuum degree of vacuum welding is 1.0 × 10⁻⁶. -2 ~2×10 -2 Pa.

6. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, In step (2), the heat treatment temperature is 1150-1200℃, and the heat treatment holding time is 30-50 min.

7. The rolling process of a titanium-steel composite plate according to claim 1, characterized in that, In step (3), the opening rolling temperature is 1100-1150℃, the final rolling temperature is 900-1000℃, the hot rolling pass is 5-8 passes, and the total rolling reduction is 78%-85%.