Easy-to-grind cold-rolled aluminum working roll and preparation method thereof
By controlling the Si and Mo content and optimizing the process, easy-to-grind cold-rolled aluminum work rolls were prepared, which solved the contradiction between high hardness and toughness, improved grinding efficiency and production stability, and reduced production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-03-13
AI Technical Summary
Existing cold-rolled aluminum work rolls struggle to achieve a balance between high hardness and toughness, have poor machinability, high production costs, and insufficient stability in mass production.
By precisely designing the alloy composition and optimizing the entire process, controlling the content range of Si and Mo, and through two-stage spheroidizing annealing, quenching and tempering treatment, combined with high-temperature diffusion annealing and stress-relieving stabilization treatment, fine and dispersed carbides and a strong and tough matrix structure are formed, improving machinability and production stability.
It achieves a balance between high hardness and toughness, significantly improving grinding efficiency and service life, reducing production costs, and enhancing the stability of mass production.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of special steel smelting and heat treatment technology, specifically relating to an easy-to-grind cold-rolled aluminum work roll and its preparation method. Background Technology
[0002] In the cold rolling process of aluminum and aluminum alloys, the work roll, as a core component directly involved in rolling deformation, directly determines the surface quality, dimensional accuracy, and production efficiency of the rolled products. Cold-rolled aluminum work rolls must simultaneously meet two core performance requirements: first, the roll surface must possess high hardness (typically HSD 95-102) to resist severe wear during rolling and ensure roll surface service life; second, the roll core must possess excellent strength and toughness to withstand alternating impact loads during rolling and prevent roll breakage or edge chipping.
[0003] To achieve the aforementioned performance requirements, existing technologies typically involve adding carbide-forming elements such as Cr, Mo, and V to the steel. These elements combine with carbon to form hard carbides, thereby improving the hardness and wear resistance of the rolls. However, this often leads to the following problems: Firstly, excessive hard carbides significantly deteriorate the machinability of the rolls. During grinding, this not only exacerbates the wear and tear on the grinding wheel and increases production costs, but also easily leads to defects such as grinding burns and microcracks on the roll surface, seriously affecting the safety of the rolls in use. Secondly, the heat treatment window in traditional manufacturing processes is narrow and highly sensitive to process parameters, easily leading to fluctuations in roll performance and poor stability in mass production.
[0004] Among them, silicon (Si) and molybdenum (Mo) are key alloying elements, and their roles are complex and interrelated: Silicon (Si): Traditionally considered a deoxidizing element, its content is usually kept low (<0.4%) to prevent deterioration of toughness and promote decarburization. However, with the development of high-Cr alloys, in order to reduce the tendency of compositional segregation, the C content is kept at a relatively low level, while the Si content is increased to more than 0.5%.
[0005] Molybdenum (Mo) is a strong carbide-forming element, providing secondary hardening ability and hardenability. However, excessive Mo can form a large number of coarse M2C carbides, which deteriorates machinability. Its interaction with Si during tempering is crucial for adjusting the type, size, and distribution of carbides.
[0006] Furthermore, existing technologies fail to fully utilize the interaction between Si and Mo during the tempering process, and cannot achieve precise control over the type, size, and distribution of carbides through elemental ratio optimization, making it difficult to achieve an ideal balance between high hardness, toughness, and machinability. Summary of the Invention
[0007] To address the problems of poor grindability, large performance fluctuations, insufficient process stability, and difficulty in balancing high hardness and toughness in existing cold-rolled aluminum work rolls, this invention provides an easily grindable cold-rolled aluminum work roll and its preparation method. Through precise design of alloy composition and optimization of the entire process, precise control of the carbide microstructure is achieved. This significantly improves grindability while ensuring high hardness and toughness of the roll, reducing production costs and enhancing the stability of mass production.
[0008] The technical solution adopted in this invention for an easily grindable cold-rolled aluminum work roll and its preparation method is as follows: A method for preparing an easily grindable cold-rolled aluminum work roll includes electroslag remelting, forging, heat treatment, and grinding. The chemical composition of the cold-rolled aluminum work roll, by weight percentage, satisfies the following: Si 0.10~0.30%, Mo 0.6~0.8%. The heat treatment includes the following steps: a) The forged roll blank is subjected to two-stage spheroidizing annealing: the first stage is held at 850~870℃, and the second stage is held at 710~730℃. b) The rolls are quenched at a temperature of 960~980℃. c) Tempering the quenched rolls: Temper at 120~150℃.
[0009] A further improvement of the technical solution of the present invention is that: after the forging step and before the two-stage spheroidizing annealing, a high-temperature diffusion annealing step is also included: the forging billet is heated to 1180~1200℃, held for 10~20 hours and then slowly cooled.
[0010] A further improvement of the technical solution of the present invention is that: in the two-stage spheroidizing annealing, the holding time of the first stage is 3 to 5 hours, and the holding time of the second stage is 10 to 15 hours.
[0011] A further improvement to the technical solution of the present invention is that the heat preservation time in step c) is calculated to be no less than 30 hours per 100mm diameter of the cold-rolled aluminum work roll.
[0012] A further improvement of the technical solution of the present invention is that: before the grinding step, a stress stabilization treatment step is included: the treatment temperature is 50~80℃, and the temperature is maintained for 15~20 hours before slow cooling.
[0013] A further improvement of the technical solution of the present invention is that the mass percentage ratio of Si to Mo in the chemical composition of the cold-rolled aluminum work roll is 0.25~0.38.
[0014] A further improvement of the technical solution of the present invention is that: in the electroslag remelting step, the chemical composition of the smelted steel ingot by weight percentage is: C 0.85~0.95%, Mn 0.30~0.60%, Cr 3.5~4.5%, V≤0.05%, Ni≤0.5%, P≤0.010%, S≤0.005%, with the balance being Fe.
[0015] An easily grindable cold-rolled aluminum work roll is prepared using the above-described method. The working layer hardness of the roll body is HSD 95~102, and the surface roughness Ra of the roll body is <0.2μm. Due to the adoption of the above technical solution, the technical progress achieved by this invention includes: This invention precisely defines the content range of Si and Mo, and controls their mass ratio within an optimized range. Si enhances the matrix strength through solid solution strengthening, while effectively suppressing the coarsening of Mo carbides during tempering, promoting their precipitation in a fine, dispersed morphology. Mo ensures sufficient hardenability and secondary hardening capacity of the roll. The synergistic effect of these two elements results in a roll microstructure with fine, rounded carbides and a strong, tough matrix, satisfying the high hardness requirement of HSD 95-102 while improving machinability and grinding efficiency, thus resolving the contradiction between high hardness and machinability.
[0016] This invention adds a high-temperature diffusion annealing step to eliminate dendritic segregation in steel ingots, laying a uniform compositional foundation for subsequent processes; the two-stage spheroidizing annealing, through the combination of high-temperature softening and low-temperature spheroidizing, obtains a uniform and stable spheroidized structure, reducing performance fluctuations in subsequent heat treatments; the low-temperature stress relief and stabilization treatment before fine grinding eliminates machining stress to the maximum extent, avoiding deformation and cracks during grinding. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of this invention.
[0018] Example 1: Preparation of φ400mm cold-rolled aluminum work rolls The steel ingots were smelted using an electroslag remelting process, with the following weight percentages of each element controlled: C: 0.85%, Si: 0.20%, Mn: 0.45%, Cr: 3.8%, Mo: 0.7% (Si / Mo=0.28), V: 0.03%, Ni: 0.2%, P: 0.008%, S: 0.003%, with the balance being Fe.
[0019] The steel ingot is heated to 1180℃ and held for 5 hours before multi-directional forging, with the total forging ratio controlled at 7.5. After forging, the billet is heated to 1200℃ for high-temperature diffusion annealing, held for 15 hours, and then slowly cooled to room temperature at a rate of 40℃ / h.
[0020] Two-stage spheroidizing annealing: The roll blank is heated to 860°C at a heating rate of 50°C / h to enter the first stage of spheroidizing annealing and held for 4 hours; then it is furnace cooled to 720°C at a rate of 25°C / h to carry out the second stage of spheroidizing annealing and held for 12 hours.
[0021] The rolls are heated to 970℃ and held for 6 hours, then quenched using a water spray cooling method. After quenching, they are immediately transferred to a tempering furnace and tempered at 130℃ for a long time, holding for 120 hours (calculated as 4×30 hours based on a roll diameter of 400mm). After tempering, they are slowly cooled to room temperature in the furnace.
[0022] After semi-precision grinding, the rolls are heated to 80°C for stress stabilization treatment and held at that temperature for 20 hours. Then, they are slowly cooled to room temperature at a rate of 15°C / h to eliminate machining stress.
[0023] Finished product inspection results: The hardness of the working layer of the roller body is HSD 97, the surface roughness is Ra=0.18μm, and there are no grinding burns or microcracks.
[0024] Example 2: Preparation of φ400mm cold-rolled aluminum work rolls The chemical composition of the steel ingot by weight percentage is as follows: C: 0.88%, Si: 0.15%, Mn: 0.40%, Cr: 4.0%, Mo: 0.6% (Si / Mo=0.25), V: 0.02%, Ni: 0.25%, P: 0.007%, S: 0.002%, with the balance being Fe.
[0025] The total forging ratio was 7.0, the high-temperature diffusion annealing temperature was 1190℃, and the holding time was 12 hours. The remaining process parameters were the same as in Example 1.
[0026] Two-stage spheroidizing annealing: The first stage involves heating to 850°C and holding for 3.5 hours; the second stage involves furnace cooling to 710°C and holding for 10 hours. Other process parameters are as described in Example 1.
[0027] Roller body heat treatment: quenching temperature 960℃, holding time 5.5 hours; tempering temperature 120℃, holding time 120 hours, other process parameters refer to Example 1.
[0028] Stress stabilization treatment: treatment temperature 70℃, heat preservation for 18 hours, other process parameters refer to Example 1.
[0029] Finished product inspection results: Roller body hardness HSD 96, surface roughness Ra=0.16μm.
[0030] Example 3: Preparation of φ400mm easy-to-grind cold-rolled aluminum work rolls The chemical composition of the steel ingot by weight percentage is as follows: C: 0.92%, Si: 0.30%, Mn: 0.45%, Cr: 4.0%, Mo: 0.8% (Si / Mo=0.375), V: 0.04%, Ni: 0.3%, P: 0.009%, S: 0.004%, with the balance being Fe.
[0031] The total forging ratio was 8.0, the high-temperature diffusion annealing temperature was 1180℃, and the holding time was 18 hours. The remaining process parameters were the same as in Example 1.
[0032] Two-stage spheroidizing annealing: The first stage involves heating to 870°C and holding for 5 hours; the second stage involves furnace cooling to 730°C and holding for 15 hours. Other process parameters are as described in Example 1.
[0033] Rough machining and flaw detection: Same as in Example 1.
[0034] Roller body heat treatment: quenching temperature 980℃, holding for 6.5 hours; tempering temperature 150℃, holding for 120 hours, other process parameters refer to Example 1.
[0035] Stress stabilization treatment: treatment temperature 50℃, heat preservation for 15 hours, other process parameters refer to Example 1.
[0036] Finished product inspection results: Roller body hardness HSD 98, surface roughness Ra=0.17μm.
[0037] Comparative Example: Preparation of φ400mm cold-rolled aluminum work rolls using traditional processes The traditional chemical composition was used: Si=0.60%, Mo=0.25% (Si / Mo=2.4), and the composition of other elements was similar to that in Example 1. The preparation process omitted high-temperature diffusion annealing and stress-relieving stabilization treatment. Spheroidizing annealing was performed at a single temperature of 780℃ for 8 hours, and tempering was performed at 550℃ for 6 hours using conventional high-temperature tempering.
[0038] Finished product test results: The roll hardness HSD 99, but the grinding wheel wear during grinding is 2.5 times that of Example 1; there are obvious short scratches and slight grinding burns on the roll surface, the surface roughness Ra=0.35μm, and the service life is shortened by about 30% compared with Example 1.
[0039] As can be seen from the comparison between the above embodiments and comparative examples, the cold-rolled aluminum work rolls prepared by the present invention, through Si-Mo synergistic regulation and whole-process process optimization, significantly improve the grindability, toughness and service life while maintaining high hardness, and the comprehensive performance far exceeds that of products made by traditional processes.
[0040] In the above embodiments, the present invention provides an easily grindable cold-rolled aluminum work roll and its preparation method. The present invention precisely defines the content range of Si and Mo and controls their mass ratio within the optimized range. Si element enhances the matrix strength through solid solution strengthening, while effectively suppressing the coarsening of Mo carbides during tempering, promoting their precipitation in a fine and dispersed form. Mo element ensures sufficient hardenability and secondary hardening capacity of the roll. The synergistic effect of the two elements results in a roll microstructure with fine, rounded carbides and a strong, tough matrix, satisfying the high hardness requirement of HSD 95-102 while improving grindability and grinding efficiency, thus resolving the contradiction between high hardness and easy grindability. The present invention adds a high-temperature diffusion annealing step to eliminate dendritic segregation in the ingot, laying a uniform compositional foundation for subsequent processes. The two-stage spheroidizing annealing, through a combination of high-temperature softening and low-temperature spheroidizing, obtains a uniform and stable spheroidized microstructure, reducing performance fluctuations in subsequent heat treatments. The low-temperature stress-relieving stabilization treatment before fine grinding eliminates machining stress to the maximum extent, avoiding deformation and cracks during grinding.
[0041] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept should fall within the protection scope of the present invention. All technical contents for which protection is sought in this invention are fully described in the claims.
Claims
1. A method for preparing an easily grindable cold-rolled aluminum work roll, comprising electroslag remelting, forging, heat treatment, and grinding, characterized in that, The chemical composition of the cold-rolled aluminum work rolls, by weight percentage, meets the following requirements: Si 0.10~0.30%, Mo 0.6~0.8%; The heat treatment includes the following steps: a) The forged roll blank is subjected to two-stage spheroidizing annealing: the first stage is held at 850~870℃, and the second stage is held at 710~730℃. b) The rolls are quenched at a temperature of 960~980℃. c) Tempering the quenched rolls: Temper at 120~150℃.
2. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that, After the forging step and before the two-stage spheroidizing annealing, a high-temperature diffusion annealing step is also included: the forging billet is heated to 1180~1200℃, held for 10~20 hours and then slowly cooled.
3. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that: In the two-stage spheroidizing annealing process, the holding time for the first stage is 3-5 hours, and the holding time for the second stage is 10-15 hours.
4. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that: The heat preservation time in step c) is calculated to be no less than 30 hours per 100mm diameter of the cold-rolled aluminum work roll.
5. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that, Before the grinding step, a stress stabilization treatment step is also included: the treatment temperature is 50~80℃, and the temperature is maintained for 15~20 hours before slow cooling.
6. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that: The mass percentage ratio of Si to Mo in the chemical composition of the cold-rolled aluminum work roll is 0.25~0.
38.
7. The method for preparing an easily grindable cold-rolled aluminum work roll according to claim 1, characterized in that, In the electroslag remelting step, the chemical composition of the smelted steel ingot by weight percentage is: C 0.85~0.95%, Mn 0.30~0.60%, Cr 3.5~4.5%, V≤0.05%, Ni≤0.5%, P≤0.010%, S≤0.005%, with the balance being Fe.
8. A work roll for easily grindable cold-rolled aluminum, characterized in that: The cold-rolled aluminum work roll is prepared using the preparation method described in any one of claims 1-7, wherein the hardness of the working layer of the roll body is HSD 95~102, and the surface roughness Ra of the roll body is <0.2μm.