High-corrosion-resistant hot-rolled thick plate and method for manufacturing the same

Abstract

The application discloses a high-corrosion-resistance hot-rolled thick plate and a preparation method thereof. The hot-rolled thick plate comprises the following components in percentage by mass: Mg 0.75-1.0 wt.%, Si 1.35-1.75 wt.%, Fe <=0.3 wt.%, Cr 0.1-0.25 wt.%, Cu <=0.1 wt.%, Zn <=0.15 wt.%, Ti <=0.15 wt.%, and the balance of Al and inevitable total impurities. The application adjusts the composition cost of the aluminum alloy material, effectively improves the aluminum alloy chemical composition and the peeling corrosion resistance, makes the tensile strength >=310Mpa, the yield strength >=270Mpa, the elongation A50 >=10%, makes the peeling corrosion test grade N, and fully meets the use requirements of the railway bridge support, and greatly prolongs the service life of the railway bridge support.

Description

Technical Field

[0001] This invention relates to a highly corrosion-resistant hot-rolled thick plate and its preparation method. Background Technology

[0002] With the continuous advancement of lightweighting, aluminum alloys, with their high specific strength, good corrosion resistance, excellent processing performance, and extremely high recyclability, have become the most ideal material for lightweighting in transportation.

[0003] Aluminum alloys exhibit strong corrosion resistance in humid, acidic, or alkaline environments, and their maintenance costs are significantly lower than those of steel throughout their lifespan. This is particularly beneficial in coastal areas where the marine atmosphere hinders the corrosion resistance of steel products, drastically shortening the lifespan of bridge bearings. Aluminum alloys effectively address the critical challenge of corrosion protection in bridge structures. 6082 aluminum alloy, possessing both sufficient strength and corrosion resistance, is poised for widespread application, especially in coastal high-speed railway bridges, although further improvements are needed.

[0004] Currently, the railway bridge bearings in China use 6082 / T6 aluminum alloy thick plates. Although their mechanical properties can meet the relevant requirements, the 6082 / T6 aluminum alloy materials produced by current technology generally have a spalling corrosion level of EA or PA, which does not meet the N-level requirement in the standard. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a highly corrosion-resistant hot-rolled thick plate, its preparation method, and its application.

[0006] A high corrosion-resistant hot-rolled thick plate, the composition of which, by mass percentage, includes: Mg 0.75–1.0 wt.%, Si 1.35–1.75 wt.%, Fe ≤0.3 wt.%, Cr 0.1–0.25 wt.%, Cu ≤0.1 wt.%, Zn ≤0.15 wt.%, Ti ≤0.15 wt.%, with the balance being Al and unavoidable total impurities. This material optimizes its chemical properties, improves its corrosion resistance, and ensures stronger chemical stability.

[0007] A method for preparing a highly corrosion-resistant hot-rolled thick plate, applied to 6082 aluminum alloy for railway bridge bearings, the method comprising:

[0008] Step 1; Material preparation: Prepare raw materials according to the above-mentioned hot-rolled thick plate composition by mass percentage. After preparing the raw materials, mix them and stir until uniform to obtain raw material A.

[0009] Step 2; Smelting: Put raw material A into a smelting furnace to obtain aluminum alloy liquid, stir it, and then pour it into a refining furnace for refining. After refining, let it stand for 20~40 minutes.

[0010] Step 3; Refinement: The refined aluminum alloy liquid is refined and then made into aluminum alloy square ingots. During the ingot casting process, the solid aluminum alloy liquid is poured into a mold and molding pressure is applied to the aluminum alloy liquid so that the aluminum alloy liquid is fixed and shaped under pressure and then cooled to room temperature.

[0011] Step 4; Preheating: Preheat the aluminum alloy square ingot, then perform heat treatment, and finally cool it again.

[0012] Step 5; Hot rolling: Heat the aluminum alloy square ingot to 420~470°C and hold it at that temperature. After holding, control the hot rolling temperature at 270~350°C. The thickness of the hot-rolled aluminum alloy sheet is 9.0mm.

[0013] Step Six; Cold Rolling: The aluminum alloy sheet is cold rolled multiple times. During the cold rolling process, the sheet is rolled from all four sides to the center. Finally, it is rolled completely from left to right once, and then rolled completely from right to left twice, thus achieving a complete cold rolling. Cold rolling the aluminum alloy sheet from all four sides effectively avoids material damage and cracking during the cold rolling process, improves the flatness of the material surface after rolling, and finally straightens it through a straightening machine to enhance the quality and effect of the material preparation, achieving an effective strengthening effect.

[0014] Step 7; Annealing: Anneal the cold-rolled aluminum alloy sheet at 250~300°C, and then saw it to obtain 6082 aluminum alloy material.

[0015] As a further improvement, in step six, the 6082 aluminum alloy material is cold-rolled multiple times to 0.5mm, successively passing through 9.0mm, 7.55mm, 5.25mm, 4.48mm, 3.5mm, 1.98mm, 0.98mm, 0.85mm, 0.65mm, and 0.5mm. During the cold rolling process, the material is gradually shaped. Multiple cold rolling can effectively prevent cracks from appearing on its edges or surface, improve surface smoothness and durability, effectively improve corrosion resistance, reduce the risk of cracking, improve safety during use, and extend service life.

[0016] As a further improvement, the refining temperature is 720~748°C and the refining time is 20 minutes.

[0017] As a further improvement, step three uses natural air cooling to cool the air to room temperature. Beneficial effects

[0018] This invention adjusts the composition of aluminum alloy material, which can effectively improve the resistance to exfoliation corrosion, resulting in a tensile strength ≥310 MPa, a yield strength ≥270 MPa, and an elongation A50 ≥10%, achieving an exfoliation corrosion test level of N, which fully meets the requirements for railway bridge bearings and greatly extends the service life of railway bridge bearings.

[0019] This invention adjusts the manufacturing steps of aluminum alloy materials, thereby enhancing their mechanical properties and resistance to exfoliation corrosion. The process is simple, energy consumption is low, and the bending performance of aluminum alloy materials is effectively improved, expanding their practical applications. Multiple cold rolling processes effectively prevent cracks from appearing on the edges or surface, improving surface smoothness and durability, effectively enhancing corrosion resistance, reducing the risk of cracking, improving safety during use, and extending service life. Cold rolling the edges of the aluminum alloy sheet effectively prevents material damage and cracking during the cold rolling process, improving the surface smoothness of the rolled material. Finally, straightening is performed using a straightening machine to enhance the quality and effect of material preparation, achieving an effective strengthening effect and ensuring the preparation effect and yield of aluminum alloy materials. Detailed Implementation

[0020] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. Example

[0021] A high corrosion-resistant hot-rolled thick plate, the composition of which, by mass percentage, includes: Mg 0.75wt.%, Si 1.35wt.%, Fe 0.3wt.%, Cr 0.15wt.%, Cu 0.1wt.%, Zn 0.15wt.%, Ti 0.15wt.%, with the balance being Al and unavoidable total impurities. This optimizes the chemical properties of the material, improves its corrosion resistance, and ensures stronger chemical stability.

[0022] A method for preparing a highly corrosion-resistant hot-rolled thick plate, applied to 6082 aluminum alloy for railway bridge bearings, the method comprising:

[0023] Step 1; Material preparation: Prepare raw materials according to the above-mentioned hot-rolled thick plate composition by mass percentage. After preparing the raw materials, mix them and stir until uniform to obtain raw material A.

[0024] Step 2; Smelting: Add raw material A into the smelting furnace to obtain aluminum alloy liquid, stir, and then pour it into the refining furnace for refining. After refining, let it stand for 20 minutes.

[0025] Step 3; Refinement: The refined aluminum alloy liquid is refined and then made into aluminum alloy square ingots. During the ingot casting process, the solid aluminum alloy liquid is poured into a mold and molding pressure is applied to the aluminum alloy liquid so that the aluminum alloy liquid is fixed and shaped under pressure and then cooled to room temperature.

[0026] Step 4; Preheating: Preheat the aluminum alloy square ingot, then perform heat treatment, and finally cool it again.

[0027] Step 5; Hot rolling: Heat the aluminum alloy square ingot to 420°C and hold it at that temperature. After holding, control the hot rolling temperature at 270°C. The thickness of the hot-rolled aluminum alloy sheet is 9.0 mm.

[0028] Step Six; Cold Rolling: The aluminum alloy sheet is cold rolled multiple times. During the cold rolling process, the sheet is rolled from all four sides to the center. Finally, it is rolled completely from left to right once, and then rolled completely from right to left twice, thus achieving a complete cold rolling. Cold rolling the aluminum alloy sheet from all four sides effectively avoids material damage and cracking during the cold rolling process, improves the flatness of the material surface after rolling, and finally straightens it through a straightening machine to enhance the quality and effect of the material preparation, achieving an effective strengthening effect.

[0029] Step 7; Annealing: The cold-rolled aluminum alloy sheet is annealed at 250°C, and then sawn to obtain 6082 aluminum alloy material.

[0030] In step six, the 6082 aluminum alloy material is cold-rolled multiple times to 0.5mm, successively passing through 9.0mm, 7.55mm, 5.25mm, 4.48mm, 3.5mm, 1.98mm, 0.98mm, 0.85mm, 0.65mm, and 0.5mm. During the cold rolling process, the material is gradually shaped. Multiple cold rolling can effectively prevent cracks from appearing on the edges or surface, improve surface smoothness and durability, effectively improve corrosion resistance, reduce the risk of cracking, improve safety during use, and extend service life.

[0031] The refining temperature is 720°C and the refining time is 20 minutes.

[0032] In step three, natural air cooling is used to restore the temperature to room temperature. Example

[0033] A high corrosion-resistant hot-rolled thick plate, the composition of which by mass percentage includes: Mg 1.0 wt.%, Si 1.75 wt.%, Fe 0.3 wt.%, Cr 0.25 wt.%, Cu 0.1 wt.%, Zn 0.15 wt.%, Ti 0.15 wt.%, with the balance being Al and unavoidable total impurities, optimizes the chemical properties of the material, improves its corrosion resistance, and ensures stronger chemical stability.

[0034] A method for preparing a highly corrosion-resistant hot-rolled thick plate, applied to 6082 aluminum alloy for railway bridge bearings, the method comprising:

[0035] Step 1; Material preparation: Prepare raw materials according to the above-mentioned hot-rolled thick plate composition by mass percentage. After preparing the raw materials, mix them and stir until uniform to obtain raw material A.

[0036] Step 2; Smelting: Add raw material A into the smelting furnace to obtain aluminum alloy liquid, stir, and then pour it into the refining furnace for refining. After refining, let it stand for 40 minutes.

[0037] Step 3; Refinement: The refined aluminum alloy liquid is refined and then made into aluminum alloy square ingots. During the ingot casting process, the solid aluminum alloy liquid is poured into a mold and molding pressure is applied to the aluminum alloy liquid so that the aluminum alloy liquid is fixed and shaped under pressure and then cooled to room temperature.

[0038] Step 4; Preheating: Preheat the aluminum alloy square ingot, then perform heat treatment, and finally cool it again.

[0039] Step 5; Hot rolling: Heat the aluminum alloy square ingot to 470°C and hold it at that temperature. After holding, control the hot rolling temperature at 350°C. The thickness of the hot-rolled aluminum alloy sheet is 9.0 mm.

[0040] Step Six; Cold Rolling: The aluminum alloy sheet is cold rolled multiple times. During the cold rolling process, the sheet is rolled from all four sides to the center. Finally, it is rolled completely from left to right once, and then rolled completely from right to left twice, thus achieving a complete cold rolling. Cold rolling the aluminum alloy sheet from all four sides effectively avoids material damage and cracking during the cold rolling process, improves the flatness of the material surface after rolling, and finally straightens it through a straightening machine to enhance the quality and effect of the material preparation, achieving an effective strengthening effect.

[0041] Step 7; Annealing: The cold-rolled aluminum alloy sheet is annealed at 300°C, and then sawn to obtain 6082 aluminum alloy material.

[0042] In step six, the 6082 aluminum alloy material is cold-rolled multiple times to 0.5mm, successively passing through 9.0mm, 7.55mm, 5.25mm, 4.48mm, 3.5mm, 1.98mm, 0.98mm, 0.85mm, 0.65mm, and 0.5mm. During the cold rolling process, the material is gradually shaped. Multiple cold rolling can effectively prevent cracks from appearing on the edges or surface, improve surface smoothness and durability, effectively improve corrosion resistance, reduce the risk of cracking, improve safety during use, and extend service life.

[0043] The refining temperature is 748°C and the refining time is 20 minutes.

[0044] In step three, natural air cooling is used to restore the temperature to room temperature.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high corrosion-resistant hot-rolled thick plate, characterized in that, The composition of the hot-rolled thick plate, by mass percentage, includes: Mg 0.75–1.0 wt.%, Si 1.35–1.75 wt.%, Fe ≤0.3 wt.%, Cr 0.1–0.25 wt.%, Cu ≤0.1 wt.%, Zn ≤0.15 wt.%, Ti ≤0.15 wt.%, with the balance being Al and unavoidable total impurities; The hot-rolled thick plate is used in railway bridge bearings, and its preparation method includes: Step 1; Material preparation: Prepare raw materials according to the above-mentioned hot-rolled thick plate composition by mass percentage. After preparing the raw materials, mix them and stir until uniform to obtain raw material A. Step 2; Smelting: Put raw material A into a smelting furnace to obtain aluminum alloy liquid, stir it, and then pour it into a refining furnace for refining. After refining, let it stand for 20~40 minutes. Step 3; Refinement: The refined aluminum alloy liquid is refined and then made into square aluminum alloy ingots. During the ingot casting process, the solid aluminum alloy liquid is poured into a mold and molding pressure is applied to the aluminum alloy liquid so that the aluminum alloy liquid is fixed and shaped under pressure and then cooled to room temperature. Step 4; Preheating: Preheat the aluminum alloy square ingot, then perform heat treatment, and finally cool it again. Step 5; Hot rolling: Heat the aluminum alloy square ingot to 420~470°C and hold it at that temperature. After holding, control the hot rolling temperature at 270~350°C. The thickness of the hot-rolled aluminum alloy sheet is 9.0mm. Step 6; Cold rolling: The aluminum alloy sheet is cold rolled multiple times. One cold rolling is specifically rolling from the four sides of the sheet to the middle, then rolling it completely from left to right, and then rolling it completely from right to left twice, thus achieving one cold rolling. Step 7; Annealing: Anneal the cold-rolled aluminum alloy sheet at 250~300°C, and then saw it to obtain the aluminum alloy material.

2. The high corrosion resistance hot-rolled thick plate according to claim 1, characterized in that, In step six, the aluminum alloy sheet is cold-rolled multiple times to 0.5mm, successively passing through 9.0mm, 7.55mm, 5.25mm, 4.48mm, 3.5mm, 1.98mm, 0.98mm, 0.85mm, 0.65mm, and 0.5mm.

3. The high corrosion resistance hot-rolled thick plate according to claim 1, characterized in that, The refining temperature is 720~748°C, and the refining time is 20 minutes.

4. The high corrosion resistance hot-rolled thick plate according to claim 1, characterized in that, In step three, natural air cooling is used to cool the air to room temperature.