Aluminum foil working roll capable of keeping high roughness and preparation method

Abstract

The invention discloses an aluminum foil working roll capable of keeping high roughness and a preparation method, and belongs to the technical field of metallurgical rollers, the aluminum foil working roll comprises the following chemical components in percentage by weight: 0.85%-0.95% of C, 0.25%-0.45% of Si, 0.20%-0.35% of Mn, 2.50%-3.50% of Cr, 0.20%-0.40% of Mo, less than or equal to 0.25% of Ni, less than or equal to 0.02% of P, less than or equal to 0.02% of S, and the balance of Fe and inevitable impurities. According to the invention, the roughness maintaining capability of the roller body of the aluminum foil working roller in the rolling process can be obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical roll technology, specifically relating to an aluminum foil work roll that maintains high roughness and its preparation method. Background Technology

[0002] With the rapid development of the modern aluminum processing industry, especially the surge in demand for high-value-added products such as high-end double-zero aluminum foil and battery foil, the market has placed extremely stringent requirements on the service performance of aluminum foil work rolls and the final surface quality of the aluminum foil. In order to adapt to this trend and improve rolling efficiency and product yield, the uniformity of roll body hardness and surface roughness has become a key process indicator.

[0003] In actual rolling processes, the microstructure of the work roll surface directly determines the surface quality and rolling stability of the aluminum foil. Typically, the work roll surface roughness is required to be maintained within the optimal range of Ra 0.6-0.8 throughout its service life to ensure a good coefficient of friction and engagement conditions. However, limited by current grinding technology and the anti-degradation properties of the roll material, the surface roughness of the aluminum foil work roll often decreases significantly to Ra 0.3-0.4 in the later stages of the rolling process. This rapid decrease not only leads to uneven surface gloss of the aluminum foil but also easily causes production instability factors such as slippage and loss of shape control.

[0004] Therefore, there is an urgent need for an aluminum foil work roll that can maintain high roughness and improve the ability of the work roll of the aluminum foil rolling mill to retain the grinding roughness, as well as a method for its preparation. Summary of the Invention

[0005] The purpose of this invention is to provide an aluminum foil work roll that maintains high roughness and its preparation method, which can effectively improve the ability of aluminum foil rolling mill work rolls to maintain grinding roughness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An aluminum foil work roll that maintains high roughness, wherein the chemical composition and weight percentage of the aluminum foil work roll material are as follows: C: 0.85%-0.95%, Si: 0.25%-0.45%, Mn: 0.20%-0.35%, Cr: 2.50%-3.50%, Mo: 0.20%-0.40%, Ni: ≤0.25%, P: ≤0.02%, S: ≤0.02%, with the remainder being Fe and unavoidable impurities.

[0007] A further improvement of the technical solution of the present invention is that: the matrix structure of the aluminum foil working roller is a spheroidized annealed structure, the roller body hardness is 100-103HSD, the roller body structure is tempered martensite and uniformly distributed carbides, and the roller body hardness uniformity is ≤1.5HSD.

[0008] A method for preparing an aluminum foil work roll that maintains high surface roughness includes the following steps: Step S1: Smelting and electroslag remelting; Step S2: Forging and pre-heat treatment; Step S3: Induction preheating and quenching; Step S4: Cold treatment and tempering.

[0009] A further improvement of the technical solution of the present invention is that: in step S1, steel raw materials are prepared according to the chemical composition and weight percentage content of the aluminum foil working roller, and initial steel ingots are prepared according to the smelting process. Then, the molten steel is further purified by electroslag remelting to remove inclusions and porosity defects inside the steel ingot.

[0010] A further improvement to the technical solution of the present invention is that step S2 includes: Step S201: Forging blank: Heat the steel ingot obtained in step S1 to 1200±20℃ and hold it for ≥5h. After holding, take it out of the furnace for forging and control the final forging temperature ≥800℃ to obtain a forging blank. Step S202: Preliminary heat treatment: First, normalizing treatment is performed. The forging blank from step S201 is heated to 920±10℃ and held for 4 hours, and then air-cooled to room temperature. After normalizing, spheroidizing annealing treatment is performed. The forging blank is first heated to 820±10℃ and held for 8 hours, then furnace-cooled to 700℃ and held for 12 hours, and finally furnace-cooled to 500℃ and removed from the furnace to obtain a pretreated blank with a uniform spheroid pearlite structure.

[0011] A further improvement of the technical solution of the present invention is that: in step S202, the spheroidizing annealing treatment transforms the carbides in the forging blank from lamellar or network-like into fine and uniform spherical particles, which are uniformly distributed on the ferrite matrix to form a spheroidized structure.

[0012] A further improvement to the technical solution of the present invention is that step S3 includes: Step S301: Preheating: Using medium-frequency induction heating, the pre-treated billet in step S202 is heated to 750-850℃, so that the temperature of the pre-treated billet rises uniformly, reducing the temperature gradient in the subsequent austenitization stage, and at the same time initially eliminating the residual stress inside the billet. Step S302: Austenitization: Using medium-frequency induction heating, the pretreated billet in step S301 is heated to 890-910℃, so that the spherical pearlite in the pretreated billet is fully transformed into a uniform austenitic structure. Step S303: Cooling: The pretreated billet in step S302 is cooled to ≤100℃ by water spraying to complete the martensitic transformation and obtain a quenched billet with martensite as the main structure.

[0013] A further improvement to the technical solution of the present invention is that step S4 includes: Step S401: Cold treatment: The quenched billet from step S303 is kept at -100±10℃ for 3 hours to promote the complete transformation of residual austenite into martensite, and a martensitic billet is obtained. Step S402: Low-temperature tempering: The blank from step S401 is kept at 110±10℃ for 60 hours to obtain a finished aluminum foil work roll with stable structure and eliminated internal stress.

[0014] A further improvement of the technical solution of the present invention is that: in step S402, during the tempering process, the C, Cr and Mo atoms dissolved in the austenitic matrix are desoluble and precipitated to form C-Cr-Mo composite carbides, which are uniformly distributed in a dispersed state on the tempered martensite matrix.

[0015] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows: The present invention relates to an aluminum foil work roll with high surface roughness and a preparation method thereof. By optimizing the preheating and quenching process of the roll blank, the matrix structure is a spheroidized structure with uniformly distributed carbides, and C-Cr-Mo forms a dispersed and uniformly distributed carbide, which significantly improves the ability of the aluminum foil work roll to maintain the surface roughness of the roll body during the rolling process.

[0016] This invention, by controlling the chemical composition of the rolls and combining it with the entire process of spheroidizing annealing, induction hardening, cold treatment, and low-temperature tempering, enables the roll body to form a dense structure of tempered martensite and uniformly dispersed C-Cr-Mo composite carbides, achieving a stable hardness of 100-103 HSD, and with a roll body hardness uniformity of ≤1.5 HSD, effectively avoiding surface defects in aluminum foil rolling caused by uneven hardness.

[0017] This invention transforms carbides from lamellar or network-like structures into fine spherical particles through spheroidizing annealing, providing a uniform microstructure for subsequent quenching. Cold treatment causes the residual austenite after quenching to completely transform into martensite, and low-temperature tempering eliminates internal stress while precipitating dispersed carbides. This process retains the high hardness and wear resistance of martensite while improving the dimensional stability of the microstructure, ensuring that the rolls maintain a stable surface roughness during long-term rolling.

[0018] This invention employs medium-frequency induction heating for preheating and austenitization treatment, achieving rapid and uniform heating of the roll blank, reducing temperature gradient and residual stress; the combination of water spray cooling and low-temperature tempering precisely controls the microstructure transformation process, avoiding blank deformation and cracking, and improving the stability of the production process and the finished product qualification rate. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to embodiments: Example 1 This embodiment provides an aluminum foil work roll that maintains high roughness. The chemical composition and weight percentage of the aluminum foil work roll material are as follows: C: 0.85%-0.95%, Si: 0.25%-0.45%, Mn: 0.20%-0.35%, Cr: 2.50%-3.50%, Mo: 0.20%-0.40%, Ni: ≤0.25%, P: ≤0.02%, S: ≤0.02%, with the remainder being Fe and unavoidable impurities. The matrix structure of the aluminum foil work roll is a spheroidized annealed structure, the roll body hardness is 100-103 HSD, the roll body microstructure consists of tempered martensite and uniformly distributed carbides, and the roll body hardness uniformity is ≤1.5 HSD.

[0020] Example 2 This embodiment provides a method for preparing an aluminum foil working roll that maintains high roughness. The preparation of the aluminum foil working roll in Embodiment 1 includes the following steps: Step S1: Smelting and electroslag remelting. Specifically, steel raw materials are prepared according to the chemical composition and weight percentage content of the aluminum foil working roll. Initial steel ingots are produced according to the smelting process. Then, the molten steel is further purified by electroslag remelting to remove inclusions and porosity defects inside the steel ingot and improve the density and composition uniformity of the steel ingot. Step S2: Forging and pre-heat treatment, specifically including the following steps: Step S201: Forging blank: Heat the steel ingot obtained in step S1 to 1200±20℃ and hold it for ≥5h. After holding, take it out of the furnace for forging and control the final forging temperature ≥800℃ to obtain the forging blank. Step S202: Preliminary heat treatment: First, normalizing treatment is performed. The forging blank from step S201 is heated to 920±10℃ and held for 4 hours, then air-cooled to room temperature. After normalizing, spheroidizing annealing treatment is performed. The forging blank is first heated to 820±10℃ and held for 8 hours, then furnace-cooled to 700℃ and held for 12 hours, and finally furnace-cooled to 500℃ before being removed from the furnace, to obtain a pretreated blank with a uniform spheroidized pearlite structure, which provides an ideal microstructure for the subsequent quenching process. Among them, the spheroidizing annealing treatment transforms the carbides in the forging blank from lamellar or network-like into fine and uniform spheroidal particles, which are evenly distributed on the ferrite matrix to form a spheroidized structure. Step S3: Induction preheating and quenching, specifically including the following steps: Step S301: Preheating: Using medium frequency induction heating, the pre-treated billet in step S202 is heated to 750-850℃, so that the temperature of the pre-treated billet rises uniformly, reducing the temperature gradient in the subsequent austenitization stage, and at the same time initially eliminating the residual stress inside the billet, avoiding the problem of uneven structure caused by subsequent high-temperature heating. Step S302: Austenitization: Using medium-frequency induction heating, the pretreated billet in step S301 is heated to 890-910℃, so that the spherical pearlite in the pretreated billet is fully transformed into a uniform austenitic structure, laying the foundation for the formation of fine martensite structure in the subsequent cooling stage. Step S303: Cooling: The pre-treated billet in step S302 is cooled to ≤100℃ by water spraying. Rapid cooling inhibits the transformation of austenite into soft structures such as pearlite and bainite, and completes the martensitic transformation to obtain a quenched billet with fine needle-like martensite as the main structure, giving the billet a high initial hardness. Step S4: Cold treatment and tempering, specifically including the following steps: Step S401: Cold treatment: The quenched billet from step S303 is kept at -100±10℃ for 3 hours to promote the complete transformation of the unstable austenite remaining after quenching into martensite, reduce the content of residual austenite in the microstructure, and obtain a martensitic billet with extremely low residual austenite content. Step S402: Low-temperature tempering: The billet from step S401 is held at 110±10℃ for 60 hours. Low-temperature tempering eliminates the internal stress generated during quenching and cold treatment, preventing deformation and cracking during subsequent processing or use. At the same time, it causes a slight tempering transformation of the martensitic structure to form tempered martensite. This structure retains the high hardness and high wear resistance of martensite, while also possessing good toughness and dimensional stability. The final product is an aluminum foil work roll with a stable structure and sufficient internal stress relief. During the tempering process, C, Cr, and Mo atoms dissolved in the austenitic matrix are desoluble and precipitated to form extremely fine C-Cr-Mo composite carbides, which are uniformly distributed in a dispersed state on the tempered martensite matrix. The finished aluminum foil work roll can form a uniform and stable rough morphology on the roll body surface. During the aluminum foil rolling process, it can effectively resist roll surface wear and fatigue spalling, maintain roll surface roughness for a long time, reduce the frequency of roll changing, and significantly improve the surface quality and production efficiency of aluminum foil rolling. It can fully meet the requirements of high roughness maintenance capability.

[0021] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A working roller for maintaining high roughness of aluminum foil, characterized in that: The chemical composition and weight percentage of the aluminum foil working roller material are as follows: C: 0.85%-0.95%, Si: 0.25%-0.45%, Mn: 0.20%-0.35%, Cr: 2.50%-3.50%, Mo: 0.20%-0.40%, Ni: ≤0.25%, P: ≤0.02%, S: ≤0.02%, with the remainder being Fe and unavoidable impurities.

2. The aluminum foil working roller for maintaining high roughness according to claim 1, characterized in that: The matrix structure of the aluminum foil working roller is spheroidized annealed structure, the roller body hardness is 100-103HSD, the roller body structure is tempered martensite and uniformly distributed carbides, and the roller body hardness uniformity is ≤1.5HSD.

3. A method for preparing an aluminum foil work roll that maintains high roughness, characterized in that: The preparation of the aluminum foil working roller according to any one of claims 1 or 2 comprises the following steps: Step S1: Smelting and electroslag remelting; Step S2: Forging and pre-heat treatment; Step S3: Induction preheating and quenching; Step S4: Cold treatment and tempering.

4. The method for preparing an aluminum foil work roll with high roughness according to claim 3, characterized in that: In step S1, steel raw materials are prepared according to the chemical composition and weight percentage content of the aluminum foil working roller, and initial steel ingots are produced according to the smelting process. Then, the molten steel is further purified by electroslag remelting to remove inclusions and porosity defects inside the steel ingot.

5. The method for preparing an aluminum foil work roll with high roughness according to claim 4, characterized in that: Step S2 includes: Step S201: Forging blank: Heat the steel ingot obtained in step S1 to 1200±20℃ and hold it for ≥5h. After holding, take it out of the furnace for forging and control the final forging temperature ≥800℃ to obtain a forging blank. Step S202: Preliminary heat treatment: First, normalizing treatment is performed. The forging blank from step S201 is heated to 920±10℃ and held for 4 hours, and then air-cooled to room temperature. After normalizing, spheroidizing annealing treatment is performed. The forging blank is first heated to 820±10℃ and held for 8 hours, then furnace-cooled to 700℃ and held for 12 hours, and finally furnace-cooled to 500℃ and removed from the furnace to obtain a pretreated blank with a uniform spheroid pearlite structure.

6. The method for preparing an aluminum foil work roll with high roughness according to claim 5, characterized in that: In step S202, the spheroidizing annealing process transforms the carbides in the forging blank from lamellar or network-like structures into fine and uniform spherical particles, which are evenly distributed on the ferrite matrix to form a spheroidized structure.

7. The method for preparing an aluminum foil work roll with high roughness according to claim 6, characterized in that: Step S3 includes: Step S301: Preheating: Using medium-frequency induction heating, the pre-treated billet in step S202 is heated to 750-850℃, so that the temperature of the pre-treated billet rises uniformly, reducing the temperature gradient in the subsequent austenitization stage, and at the same time initially eliminating the residual stress inside the billet. Step S302: Austenitization: Using medium-frequency induction heating, the pretreated billet in step S301 is heated to 890-910℃, so that the spherical pearlite in the pretreated billet is fully transformed into a uniform austenitic structure. Step S303: Cooling: The pretreated billet in step S302 is cooled to ≤100℃ by water spraying to complete the martensitic transformation and obtain a quenched billet with martensite as the main structure.

8. The method for preparing an aluminum foil work roll with high roughness according to claim 7, characterized in that: Step S4 includes: Step S401: Cold treatment: The quenched billet from step S303 is kept at -100±10℃ for 3 hours to promote the complete transformation of residual austenite into martensite, and a martensitic billet is obtained. Step S402: Low-temperature tempering: The blank from step S401 is kept at 110±10℃ for 60 hours to obtain a finished aluminum foil work roll with stable structure and eliminated internal stress.

9. The method for preparing an aluminum foil work roll with high roughness according to claim 8, characterized in that: In step S402, during the tempering process, C, Cr, and Mo atoms dissolved in the austenitic matrix are desoluble and precipitated to form C-Cr-Mo composite carbides, which are uniformly distributed in a dispersed state on the tempered martensite matrix.