Production method of cold-rolled titanium alloy strip for foldable screens

Abstract

This invention relates to a cold-rolling production method for metal strips, specifically a method for producing titanium alloy cold-rolled strips for foldable screens. Its key feature is the use of 0.5mm thick titanium alloy TA4 as raw material, undergoing at least 12 cold rolling passes, followed by cleaning and annealing / leveling treatments to produce titanium alloy strips that meet the requirements of foldable screens. This production method eliminates intermediate annealing passes; post-rolling annealing and tension leveling are integrated into a single process, simplifying the steps, reducing risk, and lowering manufacturing costs. Furthermore, by using titanium alloy TA4 as raw material and employing specific processing steps, the produced titanium alloy strips not only have a stable magnetic permeability of 1.000 (at H=50) and high tensile strength, but also exhibit good radiation resistance, enhanced stability, and no risk of transformation.

Description

Technical Field

[0001] This invention relates to a cold rolling production method for metal strip, specifically a method for producing cold-rolled titanium alloy strip for foldable screens, particularly suitable for producing titanium alloy strip for mobile phone foldable screens with a thickness of 0.15mm. Background Technology

[0002] As we all know, with the development of science and technology and the improvement of living standards, mobile phones have evolved from having only simple communication functions when they were first invented to now having multiple functions such as communication, network, navigation, games, and multimedia, and also have a beautiful and elegant appearance, becoming an indispensable tool for people's life, study and work.

[0003] In recent years, to meet people's preference for large-screen phones while maintaining portability, foldable screen phones have increasingly appeared in the public eye. The focus of foldable screen phone development lies in the foldable screen itself, requiring the metal strip used to possess high tensile strength to ensure it doesn't damage after multiple folds. Currently, the metal strips used in foldable screen phones on the market are semi-etched from low-permeability 316L stainless steel strips. While this material has good tensile strength, it suffers from the following problems:

[0004] 1. 316L austenitic stainless steel requires processes such as rolling, low magnetization, and semi-etching. The process steps are complicated, the risk of material quality changes is relatively high, and the manufacturing cost is high.

[0005] 2. 316L stainless steel strip that has undergone low magnetization treatment, because it has been cold rolled, has part of the supercooled austenite transformed into martensite, becoming a ferromagnetic structure. Its magnetic permeability will definitely exceed 1.001 (at H=50). Folding screens made from it have no shielding cover on the bent part, and will emit certain electromagnetic radiation to the environment when in operation, which cannot be avoided.

[0006] 3. During the processing (stamping, bending) of austenitic stainless steel, a new martensitic transformation inevitably occurs, forming a new ferromagnetic structure, which leads to a further increase in magnetic permeability. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a production method for cold-rolled titanium alloy strip for foldable screens. This production method has simple process steps, low risk, and can reduce manufacturing costs. Moreover, the titanium alloy strip produced not only has a stable magnetic permeability of 1.000 (at H=50) and high tensile strength, but also good radiation resistance, better stability, and no risk of transformation.

[0008] To solve the above problems, the following technical solutions are adopted:

[0009] The method for producing titanium alloy cold-rolled strip for foldable screens according to the present invention is characterized by including the following steps:

[0010] (1) Material selection

[0011] 0.5mm thick titanium alloy TA4 was selected as the raw material.

[0012] (2) Rolling

[0013] The 0.5mm thick TA4 material is rolled through no less than 12 passes to a final thickness of 0.15mm. The pass distribution is as follows: the first pass has a deformation of ≤5% and a rolling speed controlled at 80 m / min. A rough work roll with Ra0.6-0.8um is selected for blanking to solve the oxidation and adhesion problems on the surface of the raw material. After the surface hardens, the subsequent passes are controlled with a deformation of ≤10% and a work roll roughness of Ra0.3-0.4um. The last 1-2 passes use a fine work roll with Ra0.2-0.3um to roll directly to a final thickness of 0.15+ / -0.005mm, with the rolling speed controlled at 120 m / min. At this point, the surface gloss of the strip is average, but the surface is relatively fine.

[0014] (3) Cleaning

[0015] The rolled semi-finished product is degreased and cleaned at a speed of 30-50 m / min to remove the rolling oil remaining on the surface of the strip during rolling, in preparation for annealing.

[0016] (4) Annealing and leveling treatment

[0017] To ensure annealing performance and strip shape, continuous bright annealing is carried out in an argon-protected furnace. The furnace temperature is set between 640-700℃ according to the actual thickness of the rolled semi-finished product, the strip travel speed is controlled at 15m / min, and the furnace tension coefficient is increased to 0.8-1.0Kg / mm2. The strip exiting the furnace has a smooth surface without bubbles or edge waves.

[0018] (5) Cutting and packaging

[0019] Cut, package, and store according to customer requirements.

[0020] In the material selection step, the other components in the raw material titanium alloy are controlled at Al: 5.5-6.75%, V: 3.5-4.5%, and Fe: ≦0.3%.

[0021] In the annealing and leveling process, when the thickness of the rolled semi-finished product is 0.15 mm, the furnace temperature of the argon-protected furnace is selected as 650 °C.

[0022] In the annealing and leveling process, the heating section of the argon-protected furnace is 9 meters long.

[0023] The above approach has the following advantages:

[0024] The present invention discloses a method for producing cold-rolled titanium alloy strip for foldable screens. Using 0.5mm thick TA4 titanium alloy as raw material, the method involves carefully designed multi-pass rolling, followed by cleaning and special annealing and leveling treatments to produce titanium alloy strip that meets the requirements of foldable screens. This production method eliminates intermediate annealing processes; post-rolling annealing and tension leveling are integrated into a single process, simplifying the steps, reducing risks, and lowering manufacturing costs. Furthermore, by using TA4 titanium alloy as raw material and employing special processing steps, the produced titanium alloy strip not only exhibits a stable magnetic permeability of 1.000 (at H=50) and high tensile strength, but also demonstrates good radiation resistance, enhanced stability, and no risk of transformation. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] Example 1

[0027] The production method of titanium alloy cold-rolled strip for foldable screens in this embodiment is characterized by the following steps:

[0028] (1) Material selection

[0029] 0.5mm thick titanium alloy TA4 was selected as the raw material. The other components in the raw titanium alloy were controlled at Al: 5.5%, V: 3.5%, and Fe: 0.3%.

[0030] (2) Rolling

[0031] TA4 material with a thickness of 0.5 mm is rolled in 12 passes to a final thickness of 0.15 mm. The pass distribution is as follows: the first pass has a 5% deformation and a rolling speed controlled at 80 m / min. A rough work roll with a roughness of Ra 0.6-0.8 μm is selected for blanking to solve the oxidation and adhesion problems on the surface of the raw material. After the surface hardens, the subsequent passes are controlled with a 10% deformation and a work roll roughness of Ra 0.3-0.4 μm. The last two passes use a fine work roll with a roughness of Ra 0.2-0.3 μm to roll directly to a final thickness of 0.15 mm. The rolling speed is controlled at 120 m / min. At this point, the surface gloss of the strip is average, but the surface is relatively fine.

[0032] (3) Cleaning

[0033] The rolled semi-finished product is degreased and cleaned at a speed of 50 m / min to remove the rolling oil remaining on the surface of the strip during rolling, in preparation for annealing.

[0034] (4) Annealing and leveling treatment

[0035] To ensure annealing performance and strip shape, continuous bright annealing is performed in an argon-protected furnace. The furnace temperature is set between 640-700℃ based on the actual thickness of the rolled semi-finished product. In this embodiment, the thickness of the rolled semi-finished product is 0.15mm, and the furnace temperature is 650℃. The strip travel speed is controlled at 15m / min, the heating section of the argon-protected furnace is 9 meters long, and the furnace tension coefficient is increased to 0.9Kg / mm2. The strip exiting the furnace has a smooth surface, free of bubbles and edge waviness.

[0036] (5) Cutting and packaging

[0037] Cut, package, and store according to customer requirements.

[0038] Example 2

[0039] The production method of titanium alloy cold-rolled strip for foldable screens in this embodiment is characterized by the following steps:

[0040] (1) Material selection

[0041] 0.5mm thick titanium alloy TA4 was selected as the raw material. The other components in the raw titanium alloy were controlled at Al: 6.15%, V: 4.0%, and Fe: 0.2%.

[0042] (2) Rolling

[0043] TA4 material with a thickness of 0.5 mm was rolled in 13 passes to a final thickness of 0.15 mm. The pass distribution was as follows: the first pass had a 5% deformation and a rolling speed of 80 m / min, using rough work rolls with a roughness of Ra 0.6-0.8 μm to address oxidation and adhesion issues on the raw material surface; after surface hardening, subsequent passes had a 9% deformation and a work roll roughness of Ra 0.3-0.4 μm; the last two passes used fine work rolls with a roughness of Ra 0.2-0.3 μm to directly roll to a final thickness of 0.155 mm (meeting a tolerance of 0.15 + / - 0.005 mm), with the rolling speed controlled at 120 m / min. At this point, the strip surface had a moderate gloss but a relatively fine surface.

[0044] (3) Cleaning

[0045] The rolled semi-finished product is degreased and cleaned at a speed of 40 m / min to remove the rolling oil remaining on the surface of the strip during rolling, in preparation for annealing.

[0046] (4) Annealing and leveling treatment

[0047] To ensure annealing performance and strip shape, continuous bright annealing is performed in an argon-protected furnace. The furnace temperature is set between 640-700℃ based on the actual thickness of the rolled semi-finished product. In this embodiment, the thickness of the rolled semi-finished product is 0.155mm, and the furnace temperature is 700℃. The strip travel speed is controlled at 15m / min, the heating section length of the argon-protected furnace is 9 meters, the furnace tension coefficient is increased to 1.0Kg / mm2, and the strip exiting the furnace has a smooth surface without bubbles or edge waviness.

[0048] (5) Cutting and packaging

[0049] Cut, package, and store according to customer requirements.

[0050] Example 3

[0051] The production method of titanium alloy cold-rolled strip for foldable screens in this embodiment is characterized by the following steps:

[0052] (1) Material selection

[0053] 0.5mm thick titanium alloy TA4 was selected as the raw material. Other components in the raw titanium alloy were controlled at Al: 6.75%, V: 4.5%, and Fe: 0.1%.

[0054] (2) Rolling

[0055] TA4 material with a thickness of 0.5 mm is rolled in 15 passes to a final thickness of 0.15 mm. The pass distribution is as follows: the first pass has a 5% deformation and a rolling speed controlled at 80 m / min. A rough work roll with a roughness of Ra 0.6-0.8 μm is selected for blanking to solve the oxidation and adhesion problems on the surface of the raw material. After the surface hardens, the subsequent passes are controlled with an 8% deformation and a work roll roughness of Ra 0.3-0.4 μm. The final pass uses a fine work roll with a roughness of Ra 0.2-0.3 μm to roll directly to a final thickness of 0.145 mm (meeting the tolerance of 0.15 + / - 0.005 mm). The rolling speed is controlled at 120 m / min. At this point, the surface gloss of the strip is average, but the surface is relatively fine.

[0056] (3) Cleaning

[0057] The rolled semi-finished product is placed on a degreasing and cleaning unit at a speed of 30 m / min to remove the rolling oil remaining on the surface of the strip during rolling, in preparation for annealing.

[0058] (4) Annealing and leveling treatment

[0059] To ensure annealing performance and strip shape, continuous bright annealing is performed in an argon-protected furnace. The furnace temperature is set between 640-700℃ based on the actual thickness of the rolled semi-finished product. In this embodiment, the thickness of the rolled semi-finished product is 0.145mm, and the furnace temperature is 640℃. The strip travel speed is controlled at 15m / min, the heating section of the argon-protected furnace is 9 meters long, and the furnace tension coefficient is increased to 0.8-1.0Kg / mm2. The strip exiting the furnace has a smooth surface, free of bubbles and edge waviness.

[0060] (5) Cutting and packaging

[0061] Cut, package, and store according to customer requirements.

[0062] The production method of cold-rolled titanium alloy strip for foldable screens in this invention eliminates the intermediate annealing process. The annealing and tension leveling after rolling are integrated into one step, simplifying the process, reducing risk, and lowering manufacturing costs. Furthermore, using TA4 titanium alloy as raw material and undergoing special processing steps, the produced titanium alloy strip not only has a stable magnetic permeability of 1.000 (at H=50) and high tensile strength, but also exhibits good radiation resistance, enhanced stability, and no risk of transformation.

Claims

1. A method for producing cold-rolled titanium alloy strip for foldable screens, characterized in that... Includes the following steps: (1) Material selection 0.5mm thick titanium alloy TA4 was selected as the raw material for future use; (2) Rolling TA4 material with a thickness of 0.5 mm is rolled through no less than 12 passes to a final thickness of 0.15 mm. The pass distribution is as follows: the first pass has a rolling deformation of ≤5%, the rolling speed is controlled at 80 m / min, and a rough work roll with Ra0.6-0.8 μm is selected for blanking; after surface hardening, the subsequent passes are controlled with a deformation of ≤10%, and the work roll roughness is Ra0.3-0.4 μm; the last 1-2 passes use a fine work roll with Ra0.2-0.3 μm to directly roll to a final thickness of 0.15 + / -0.005 mm, and the rolling speed is controlled at 120 m / min. (3) Cleaning The rolled semi-finished product is degreased and cleaned at a speed of 30-50 m / min to remove the rolling oil remaining on the surface of the strip during rolling, in preparation for annealing. (4) Annealing and leveling treatment Continuous bright annealing is carried out in an argon-protected furnace. The furnace temperature is set between 640-700℃ according to the actual thickness of the rolled semi-finished product. The strip travel speed is controlled at 15m / min, and the furnace tension coefficient is increased to 0.8-1.0Kg / mm2. (5) Cut, package and put into storage.

2. The method for producing cold-rolled titanium alloy strip for foldable screens as described in claim 1, characterized in that... In the material selection step, the other components in the raw material titanium alloy are controlled at Al: 5.5-6.75%, V: 3.5-4.5%, and Fe: ≦0.3%.

3. The method for producing cold-rolled titanium alloy strip for foldable screens as described in claim 1, characterized in that... In the annealing and leveling process, when the thickness of the rolled semi-finished product is 0.15 mm, the furnace temperature of the argon-protected furnace is selected as 650 °C.

4. The method for producing cold-rolled titanium alloy strip for foldable screens as described in any one of claims 1 to 3, characterized in that... In the annealing and leveling process, the heating section of the argon-protected furnace is 9 meters long.