Aluminum alloy material for preparing steel-aluminum composite strip and preparation method of aluminum alloy material

Abstract

The invention relates to the technical field of aluminum alloy material pressure processing, in particular to an aluminum alloy material for preparing a steel-aluminum composite strip and a preparation method thereof.The aluminum alloy material comprises a steel layer and an aluminum alloy layer, and the aluminum alloy layer comprises, by mass, 100 parts of silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn) and the balance aluminum and inevitable impurity elements. According to the method, through the laser interface activation and ultrasonic-assisted rolling technology, the interface bonding degree and the microstructure of the steel-aluminum composite material are remarkably improved, and the stability of the steel-aluminum composite material at the high temperature is optimized. And microalloying elements such as scandium (Sc) are introduced, so that the mechanical property and the corrosion resistance of the material are enhanced. The service life is prolonged through a special high-temperature-resistant coating and an accurate heat treatment process, and the surface hardness and corrosion resistance are improved. The advanced processes ensure high performance and high quality of the composite material, and meet the requirements of high temperature and special environments.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure processing of aluminum alloy materials, and in particular to an aluminum alloy material for preparing a steel-aluminum composite strip and a preparation method thereof. Background Art

[0002] Aluminum / steel composite material is a metal layered structure composite material, which is widely used in the fields of electricity, automobile and decoration. The main materials for manufacturing air-cooled steam condensers in steam power generation, automobile engine heat shields, etc. are mostly aluminum / steel composite materials. The matrix material of traditional aluminum / steel composite materials is generally low-carbon steel; the cladding material is generally 1000 series industrial pure aluminum. The traditional aluminum / steel composite material has a low operating temperature. During high-temperature brazing (600℃±10℃), the interface between steel and aluminum is very likely to generate coarse and continuous iron-aluminum intermetallic brittle compounds, causing the aluminum layer to separate from the steel layer. Its disadvantage is that when ordinary 1050 aluminum alloy is compounded with steel strip, brittle compounds such as FeAl3 and Fe3Al5 are easily generated at the aluminum-steel composite interface at high temperature, thereby reducing the composite strength of the aluminum-steel composite strip. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems raised in the above background technology.

[0004] The present invention adopts the following technical scheme: an aluminum alloy material for preparing a steel-aluminum composite strip, comprising a steel layer and an aluminum alloy layer, wherein the aluminum alloy layer comprises 100 parts by weight of the following materials: silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn), and the rest are aluminum and unavoidable impurity elements.

[0005] Preferably, the sum of the unavoidable impurity elements in the aluminum alloy layer and the steel layer is no more than 0.15 parts, and the content of a single impurity element is no more than 0.05 parts.

[0006] Preferably, the silicon (Si) content is 4%, the iron (Fe) content is 0.7%, the copper (Cu) content is 0.3%, the manganese (Mn) content is 1.2%, the magnesium (Mg) content is 0.8%, and the zinc (Zn) content is 0.14%.

[0007] Preferably, the silicon (Si) content in the aluminum alloy layer is increased, and an iron-aluminum-silicon ternary compound is generated at the interface under the effect of interface composite microalloying during high-temperature brazing.

[0008] Preferably, the alloying process introduces the microalloying element scandium (Sc) in a proportion of about 0.1% to 0.5% of the total alloy amount.

[0009] Preferably, the composite interface is optimized by using ultrasonic assisted rolling technology to enhance the bonding degree of the interface and the strength of the overall material.

[0010] Preferably, after the milling treatment, laser is used to perform interface activation treatment on the steel and aluminum alloy surfaces to improve their interface activity.

[0011] Preferably, the annealing process is followed by controlled cooling to precisely adjust the microstructure of the material.

[0012] Preferably, a special high temperature resistant coating is applied to the finished product to improve the surface properties of the material.

[0013] A method for preparing an aluminum alloy material for preparing a steel-aluminum composite strip comprises the following steps:

[0014] S1: Milling: Mill the two large faces of the ingot by about 7.5 mm each to remove the surface oxide layer and segregation part;

[0015] S2: Interface activation treatment: after milling, the laser is used to activate the surface of steel and aluminum alloy to improve its interface activity. The power is set to 500W and the scanning speed is 100mm / s to ensure uniform treatment.

[0016] S3: Heating, placing the ingot after the interface activation treatment into a heating furnace for heating and heat preservation, the heating temperature is controlled at 540±5°C, the heat preservation temperature is 525±5°C, and the total time is not less than 12 hours;

[0017] S4: Hot rolling: the heated ingot is rolled into coils by a hot rolling mill, the starting rolling temperature is 450-480°C, the final rolling temperature is not less than 310°C, and the thickness of the coils after hot rolling is 4.5±0.2mm;

[0018] S5: Cold rough rolling, the coil is processed to a thickness of 1.0 mm through multiple cold rolling;

[0019] S6: Introduction of microalloying elements: During the cold rolling process, the microalloying element scandium (Sc) is introduced through an alloying process, with a proportion of about 0.1% to 0.5% of the total alloy amount to optimize the microstructure and properties of the alloy;

[0020] S7: Edge trimming: Use the rewinding edge trimming machine to remove the uneven parts of 30-50mm on both sides of the coil to ensure the edge quality and provide accurate size for subsequent finishing and application;

[0021] S8: cold finishing rolling, continue with multiple passes of cold rolling until the final required thickness is reached, generally 0.15-0.2mm;

[0022] S9: Composite interface optimization, using ultrasonic assisted rolling technology, with ultrasonic vibration frequency set to 20kHz and amplitude of 10μm, acting on the rolling rollers to optimize the steel-aluminum composite interface during the cold finishing step, enhancing the bonding degree of the interface and the strength of the overall material;

[0023] S10: Finished product annealing, the coil is completely annealed, the furnace temperature is raised to 300℃, kept at this temperature for 11 hours, then the furnace temperature is lowered to 250℃, kept at this temperature for another 4 hours before being taken out of the furnace, and the finished product is in the O state. During annealing, nitrogen protection is used throughout the process, and the oxygen content in the furnace is required to be below 0.2% to ensure that there will be no defects such as oil spots on the surface of the coil;

[0024] S11: Controlled cooling: After the annealing process, controlled cooling is immediately performed to precisely adjust the microstructure of the material. The cooling rate is controlled between 1°C / min and 5°C / min to achieve uniform cooling in different areas and avoid internal stress concentration.

[0025] S12: Surface treatment and coating: applying special high temperature resistant coating to improve the surface performance of the material. The coating material is silane-based heat resistant coating with a thickness of 5μm to 10μm.

[0026] S13: Finished product slitting: according to customer needs, the coils are slit into different widths and packaged for storage.

[0027] Compared with the prior art, the advantages and positive effects of the present invention are:

[0028] In the present invention, the interface bonding degree between steel and aluminum alloy is significantly improved by laser interface activation treatment and ultrasonic assisted rolling technology, the microstructure of the composite material is optimized and the high temperature stability is enhanced. The introduction of microalloying elements such as scandium (Sc) further improves the mechanical properties and corrosion resistance of the material, while the special high temperature resistant coating technology effectively extends the service life of the material and improves the surface hardness and corrosion resistance. In addition, precise heating and annealing processes and dimensional control technologies ensure the high performance and quality of the composite material, making it suitable for demanding high temperature environments. In general, this solution not only improves the overall performance of the composite material, including strength, corrosion resistance, and high temperature stability, but also significantly improves its application potential in high temperature and special environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention proposes an aluminum alloy material for preparing a steel-aluminum composite strip and a flow chart of a preparation method thereof. DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0032] Example

[0033] See also Figure 1 The present invention provides a technical solution: an aluminum alloy material for preparing a steel-aluminum composite strip, comprising a steel layer and an aluminum alloy layer, the aluminum alloy layer comprising 100 parts by weight of the following materials: silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn), and the rest being aluminum and unavoidable impurity elements.

[0034] Furthermore, the sum of unavoidable impurity elements in the aluminum alloy layer and the steel layer is not greater than 0.15 parts, and the content of a single impurity element is not greater than 0.05 parts.

[0035] Furthermore, the content of silicon (Si) is 4%, the content of iron (Fe) is 0.7%, the content of copper (Cu) is 0.3%, the content of manganese (Mn) is 1.2%, the content of magnesium (Mg) is 0.8%, and the content of zinc (Zn) is 0.14%.

[0036] Furthermore, the silicon (Si) content in the aluminum alloy layer increases, and under the effect of interface composite microalloying during high-temperature brazing, an iron-aluminum-silicon ternary compound is generated at the interface.

[0037] Furthermore, the alloying process introduces a microalloying element scandium (Sc) in a proportion of about 0.1% to 0.5% of the total alloy amount.

[0038] Furthermore, the composite interface is optimized by using ultrasonic assisted rolling technology to enhance the bonding degree of the interface and the strength of the overall material.

[0039] Furthermore, after the milling treatment, the surface of the steel and aluminum alloy is subjected to interface activation treatment by laser to improve its interface activity.

[0040] Furthermore, the annealing process is followed by controlled cooling to precisely adjust the material's microstructure.

[0041] Furthermore, a special high temperature resistant coating is applied to the finished product to improve the surface properties of the material.

[0042] A method for preparing an aluminum alloy material for preparing a steel-aluminum composite strip comprises the following steps:

[0043] S1: Milling: Mill the two large faces of the ingot by about 7.5 mm each to remove the surface oxide layer and segregation part;

[0044] S2: Interface activation treatment: after milling, the laser is used to activate the surface of steel and aluminum alloy to improve its interface activity. The power is set to 500W and the scanning speed is 100mm / s to ensure uniform treatment.

[0045] S3: Heating, placing the ingot after the interface activation treatment into a heating furnace for heating and heat preservation, the heating temperature is controlled at 540±5°C, the heat preservation temperature is 525±5°C, and the total time is not less than 12 hours;

[0046] S4: Hot rolling: the heated ingot is rolled into coils by a hot rolling mill, the starting rolling temperature is 450-480°C, the final rolling temperature is not less than 310°C, and the thickness of the coils after hot rolling is 4.5±0.2mm;

[0047] S5: Cold rough rolling, the coil is processed to a thickness of 1.0 mm through multiple cold rolling;

[0048] S6: Introduction of microalloying elements: During the cold rolling process, the microalloying element scandium (Sc) is introduced through an alloying process, with a proportion of about 0.1% to 0.5% of the total alloy amount to optimize the microstructure and properties of the alloy;

[0049] S7: Edge trimming: Use the rewinding edge trimming machine to remove the uneven parts of 30-50mm on both sides of the coil to ensure the edge quality and provide accurate size for subsequent finishing and application;

[0050] S8: cold finishing rolling, continue with multiple passes of cold rolling until the final required thickness is reached, generally 0.15-0.2mm;

[0051] S9: Composite interface optimization, using ultrasonic assisted rolling technology, with ultrasonic vibration frequency set to 20kHz and amplitude of 10μm, acting on the rolling rollers to optimize the steel-aluminum composite interface during the cold finishing step, enhancing the bonding degree of the interface and the strength of the overall material;

[0052] S10: Finished product annealing, the coil is completely annealed, the furnace temperature is raised to 300℃, kept at this temperature for 11 hours, then the furnace temperature is lowered to 250℃, kept at this temperature for another 4 hours before being taken out of the furnace, and the finished product is in the O state. During annealing, nitrogen protection is used throughout the process, and the oxygen content in the furnace is required to be below 0.2% to ensure that there will be no defects such as oil spots on the surface of the coil;

[0053] S11: Controlled cooling: After the annealing process, controlled cooling is immediately performed to precisely adjust the microstructure of the material. The cooling rate is controlled between 1°C / min and 5°C / min to achieve uniform cooling in different areas and avoid internal stress concentration.

[0054] S12: Surface treatment and coating: applying special high temperature resistant coating to improve the surface performance of the material. The coating material is silane-based heat resistant coating with a thickness of 5μm to 10μm.

[0055] S13: Finished product slitting: according to customer needs, the coils are slit into different widths and packaged for storage.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An aluminum alloy material for preparing a steel-aluminum composite strip, comprising a steel layer and an aluminum alloy layer, characterized in that: The aluminum alloy layer includes the following materials with a total mass fraction of 100 parts: silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn), and the rest is aluminum and inevitable impurity elements.

2. The aluminum alloy material for preparing the steel-aluminum composite strip according to claim 1, characterized in that: The sum of the inevitable impurity elements in the aluminum alloy layer and the steel layer is no more than 0.15 parts, and the single impurity element is no more than 0.05 parts.

3. The aluminum alloy material for preparing the steel-aluminum composite strip according to claim 1, characterized in that: The content of silicon (Si) is 4%, the content of iron (Fe) is 0.7%, the content of copper (Cu) is 0.3%, the content of manganese (Mn) is 1.2%, the content of magnesium (Mg) is 0.8%, and the content of zinc (Zn) is 0.14%.

4. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: The silicon (Si) content in the aluminum alloy layer increases, and under the effect of interface composite microalloying during high-temperature brazing, an iron-aluminum-silicon ternary compound is generated at the interface.

5. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: The alloying process introduces the microalloying element scandium (Sc) in a proportion of about 0.1% to 0.5% of the total alloy amount.

6. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: The composite interface optimization adopts ultrasonic assisted rolling technology to enhance the bonding degree of the interface and the strength of the overall material.

7. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: After the milling treatment, laser is used to perform interface activation treatment on the steel and aluminum alloy surfaces to improve their interface activity.

8. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: The annealing process is followed by controlled cooling in order to precisely adjust the microstructure of the material.

9. The aluminum alloy material for preparing a steel-aluminum composite strip according to claim 1, characterized in that: The finished product is applied with a special high temperature resistant coating to improve the surface properties of the material.

10. The method for preparing an aluminum alloy material for preparing a steel-aluminum composite strip according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Milling: Mill the two large faces of the ingot by about 7.5 mm each to remove the surface oxide layer and segregation part; S2: Interface activation treatment: after milling, the laser is used to activate the surface of steel and aluminum alloy to improve its interface activity. The power is set to 500W and the scanning speed is 100mm / s to ensure uniform treatment. S3: Heating, placing the ingot after the interface activation treatment into a heating furnace for heating and heat preservation, the heating temperature is controlled at 540±5°C, the heat preservation temperature is 525±5°C, and the total time is not less than 12 hours; S4: Hot rolling: the heated ingot is rolled into coils by a hot rolling mill, the starting rolling temperature is 450-480°C, the final rolling temperature is not less than 310°C, and the thickness of the coils after hot rolling is 4.5±0.2mm; S5: Cold rough rolling, the coil is processed to a thickness of 1.0 mm through multiple cold rolling; S6: Introduction of microalloying elements: During the cold rolling process, the microalloying element scandium (Sc) is introduced through an alloying process, with a proportion of about 0.1% to 0.5% of the total alloy amount to optimize the microstructure and properties of the alloy; S7: Edge trimming: Use the rewinding edge trimming machine to remove the uneven parts of 30-50mm on both sides of the coil to ensure the edge quality and provide accurate size for subsequent finishing and application; S8: cold finishing rolling, continue with multiple passes of cold rolling until the final required thickness is reached, generally 0.15-0.2mm; S9: Composite interface optimization, using ultrasonic assisted rolling technology, with ultrasonic vibration frequency set to 20kHz and amplitude of 10μm, acting on the rolling rollers to optimize the steel-aluminum composite interface during the cold finishing step, enhancing the bonding degree of the interface and the strength of the overall material; S10: Finished product annealing, the coil is completely annealed, the furnace temperature is raised to 300℃, kept at this temperature for 11 hours, then the furnace temperature is lowered to 250℃, kept at this temperature for another 4 hours before being taken out of the furnace, and the finished product is in the O state. During annealing, nitrogen protection is used throughout the process, and the oxygen content in the furnace is required to be below 0.2% to ensure that there will be no defects such as oil spots on the surface of the coil; S11: Controlled cooling: After the annealing process, controlled cooling is immediately performed to precisely adjust the microstructure of the material. The cooling rate is controlled between 1°C / min and 5°C / min to achieve uniform cooling in different areas and avoid internal stress concentration. S12: Surface treatment and coating: applying special high temperature resistant coating to improve the surface performance of the material. The coating material is silane-based heat resistant coating with a thickness of 5μm to 10μm. S13: Finished product slitting: according to customer needs, the coils are slit into different widths and packaged for storage.

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