Manufacturing process of tool steel roller for rolling finished magnetic pole steel rack

Abstract

The invention relates to a manufacturing process of a tool steel roller for rolling a finished product magnetic pole steel rack. The manufacturing process comprises the following steps: S1, optimally selecting and configuring chemical components: 0.55-0.65% of C; si: 0.55%-0.75%; 0.70% to 0.85% of Mn; p is less than or equal to 0.030%; s is less than or equal to 0.025%; cr: 4.60%-5.60%; 0.80% to 1.00% of Ni; 0.65% to 0.75% of Mo; 0.20% to 0.30% of V; 0.015% to 0.025% of Re; s2, a smelting process; s3, special heat treatment; and S4, roller detection. According to the manufacturing process, a matrix structure which is good in wear resistance and basically free of hardness difference, and high in toughness strength and heat crack resistance are achieved.

Description

Technical Field

[0001] This invention relates to the technical field of roll manufacturing processes, and in particular to a manufacturing process for tool steel rolls used in rolling finished magnetic pole steel frames. Background Technology

[0002] Magnetic pole steel is used to manufacture the cores of small and medium-sized DC generators, which are mostly used in automobiles and tractors. With the rapid development of my country's economy, high-tech new energy vehicles have achieved significant breakthroughs and formed large-scale industrialization, exceeding ten million vehicles in production capacity, entering the world's first-class market, and leading the world in high-tech automotive technology. Energy-saving and environmentally friendly, they are widely welcomed by people worldwide. Therefore, under this favorable situation, the variety and quantity of magnetic pole steel are constantly increasing. Previously, magnetic pole steel was produced using hot forging, which had low productivity and high material consumption. After entering the new century, with the rapid development of rolling mills and rolling technology, the adoption of hot rolling processes not only saved a lot of labor time, metal materials, and energy, but also achieved a new breakthrough in production efficiency. To further improve the surface and internal quality of magnetic pole steel products, most are made of traditional pearlitic III and bainitic I ductile iron. These rolls are used in the finished product stand. Because there are many varieties of magnetic pole steel products and the rolling die is relatively deep, the rolls made of the aforementioned ductile iron material all have a certain degree of hardness difference. Moreover, as the number of times the rolls are repaired and ground increases, the hardness difference becomes even greater. These phenomena directly affect the surface quality of the rolled product and the rolling operation efficiency, and will also cause the rolls to fail prematurely, further increasing the production cost of steel rolling enterprises and reducing operational efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is as follows: In order to solve the problems existing in the background art, a manufacturing process for tool steel rolls for rolling finished magnetic pole steel frames is provided. Based on the relatively simple shape of the magnetic pole steel assembly, with a thick head and symmetrical legs, and the main function of the finished die is to bend the back step into an arc shape in the working environment, a horizontal frame is adopted. In order to ensure that all parts of the die of the upper and lower roller groove combination have good wear resistance, a matrix structure with basically no hardness difference, high toughness and strength, and resistance to thermal cracking are required.

[0004] The technical solution adopted by this invention to solve its technical problem is: a manufacturing process for tool steel rolls used in rolling finished magnetic pole steel frames, comprising the following steps: S1, optimizing and configuring chemical composition: C: 0.55%-0.65%; Si: 0.55%-0.75%; Mn: 0.70%-0.85%; P≤0.030%; S≤0.025%; Cr: 4.60%-5.60%; Ni: 0.80%-1.00%; Mo: 0.65%-0.75%; V: 0.20%-0.30%; Re: 0.015%-0.025%; S2, smelting process; S3, special heat treatment; S4, roll inspection.

[0005] Further specifying, in the above technical solution, the S2 smelting process is as follows: the rolls are made in an electric arc furnace, the ladle refining furnace is used for vacuum smelting of high-quality molten steel, argon gas is blown throughout the process to create foamy white slag, the tapping temperature is 80℃-120℃ at the liquidus temperature, and the steel is calmed for 6-8 minutes before pouring.

[0006] Further specifying, in the above technical solution, S3, the special heat treatment includes the following steps: S11, high-temperature diffusion annealing, heating the high-alloy steel rolled magnetic pole steel finished roll to 150℃-250℃ above AC3 and holding at 25mm / h. The purpose of diffusion treatment is to eliminate the presence of dendritic water crystals and alloy composition segregation during roll solidification, so that the atoms of alloy elements can diffuse fully and obtain a uniform austenitic structure; S22, then performing spheroidizing annealing treatment to improve the cutting performance of the roll and prepare the structure accordingly for subsequent quenching treatment. The spheroidizing treatment temperature is slightly higher than the AC1 critical point. If the temperature is too low, the required spheroidizing time will be too long, and if the temperature is too high, granular pearlite with varying particle size will appear; S33, then normalizing to 940℃-960℃ and holding for a certain time, followed by spray quenching, and tempering when the roll temperature reaches 430℃-450℃.

[0007] Further specifying, in the above technical solution, the S4 and roll test results are as follows: fine-grained metallic carbides are uniformly distributed, the roll surface hardness is 70-75HSD, the hardness difference from the working layer to the bottom of the groove is ≤1.5HSD, and the tensile strength is ≥750MPa; the metallographic matrix is ​​fine-grained metallic carbides + tempered sorbite + bainite + martensite.

[0008] A tool steel roll for rolling finished magnetic pole steel frames includes an upper roll and a lower roll arranged horizontally. The middle of the upper roll and the middle of the lower roll are respectively provided with a first working section and a second working section. The first working section has an annular stepped groove, and the second working section has an arc-shaped protrusion. The arc-shaped protrusion is embedded in the annular stepped groove to form the cross-section of the magnetic pole steel.

[0009] Furthermore, in the above technical solution, tapered bearing stops are provided at both ends of the first working section and both ends of the second working section.

[0010] Furthermore, in the above technical solution, one end of the tapered bearing stop is provided with a flat square transmission end.

[0011] Furthermore, in the above technical solution, the other end of the tapered bearing stop is provided with a columnar connecting section.

[0012] Furthermore, in the above technical solution, one end of the columnar connecting section is vertically provided with a threaded lifting hole.

[0013] Furthermore, in the above technical solution, an annular groove is provided on the columnar connecting section.

[0014] The beneficial effects of this invention are as follows: The process for tool steel rolls used in rolling finished magnetic pole steel frames proposed in this invention is based on the relatively simple shape of the magnetic pole steel assembly, with a thick head, symmetrical legs, and the main function of the finished die being to bend the back into an arc shape in the working environment, and a horizontal frame is adopted; in order to ensure that all parts of the die of the upper and lower roller groove combination have good wear resistance, a matrix structure with basically no hardness difference, high toughness and strength, and resistance to thermal cracking are required. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the cross-section of the magnetic pole steel in this invention.

[0017] The labels in the attached diagram are as follows: 1. Upper roller, 2. Lower roller, 3. First working section, 4. Second working section, 5. Annular stepped groove, 6. Arc-shaped protrusion, 7. Magnetic pole steel, 8. Conical bearing stop, 9. Flat square transmission end, 10. Columnar connecting section, 11. Threaded lifting hole, 12. Annular groove. Detailed Implementation

[0018] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] The manufacturing process of the tool steel rolls in this application is as follows: 1. Optimize and select the chemical composition: C: 0.55%-0.65%; Si: 0.55%-0.75%; Mn: 0.70%-0.85%; P≤0.030%; S≤0.025%; Cr: 4.60%-5.60%; Ni: 0.80%-1.00%; Mo: 0.65%-0.75%; V: 0.20%-0.30%; Re: 0.015%-0.025%; 2. Smelting Process: The rolls are produced using an electric arc furnace and a ladle refining furnace with vacuum smelting of high-quality molten steel. Argon gas is blown throughout the process to create foamy white slag. The tapping temperature is between 80℃ and 120℃ (liquid phase temperature), followed by 6-8 minutes of calming before casting. 3. Special heat treatment: 1) High-temperature diffusion annealing: The high-alloy steel rolled magnetic pole steel finished rolls are heated to 150℃-250℃ above AC3 and held at 25mm / h. The purpose of the diffusion treatment is to eliminate the presence of dendritic water crystals and alloy component segregation during roll solidification, allowing the atoms of alloying elements to diffuse fully and obtain the desired result. 1) The roll has a uniform austenitic structure; 2) Next, spheroidizing annealing is performed to improve the cutting performance of the roll and prepare the microstructure for subsequent quenching. The spheroidizing temperature is slightly higher than the AC1 critical point. If the temperature is too low, the spheroidizing time will be too long, and if the temperature is too high, granular pearlite with varying particle sizes will appear; 3) Then, the roll is normalized to 940℃-960℃ and held for a certain time before being spray-quenched. The roll is then tempered when the temperature reaches 430℃-450℃. The purpose of the spray-quenching treatment is mainly to ensure that the working layer of the roll has a good working quality. By utilizing the structure, the role of alloying elements in the roll is fully utilized to improve the hardness and wear resistance of the working layer of the roll body; 4. Roll inspection results: fine granular metallic carbides are evenly distributed, the roll surface hardness is 70-75HSD, the hardness difference from the working layer to the bottom of the groove is ≤1.5HSD, and the tensile strength is ≥750MPa; the metallographic matrix is ​​fine granular metallic carbides + tempered sorbite + bainite + martensite; 5. After being used by customers on the machine, the rolling capacity of the rolls has increased by 65% ​​compared with traditional rolls, achieving good use benefits.

[0020] See Figure 1 and Figure 2 The image shows a tool steel roll for rolling finished magnetic pole steel frames, including an upper roll 1 and a lower roll 2 arranged horizontally. The middle of the upper roll 1 and the middle of the lower roll 2 are respectively provided with a first working section 3 and a second working section 4. The first working section 3 has an annular stepped groove 5, and the second working section 4 has an arc-shaped protrusion 6. The arc-shaped protrusion 6 is embedded in the annular stepped groove 5 to form the cross section of the magnetic pole steel 7.

[0021] The first working section 3 and the second working section 4 are both equipped with tapered bearing stops 8. One end of the tapered bearing stop 8 is equipped with a flat square transmission end 9. The other end of the tapered bearing stop 8 is equipped with a columnar connecting section 10. One end of the columnar connecting section 10 is vertically equipped with a threaded lifting hole 11. An annular groove 12 is provided on the columnar connecting section 10.

[0022] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for tool steel rolls for rolling finished product magnetic pole steel beds, characterized by, The process includes the following steps: S1, Optimizing and selecting the chemical composition: C: 0.55%-0.65%; Si: 0.55%-0.75%; Mn: 0.70%-0.85%; P≤0.030%; S≤0.025%; Cr: 4.60%-5.60%; Ni: 0.80%-1.00%; Mo: 0.65%-0.75%; V: 0.20%-0.30%; Re: 0.015%-0.025%; S2, smelting process; S3, special heat treatment; S4, roll inspection.

2. The manufacturing process of a tool steel roll for rolling finished magnetic pole steel frames as described in claim 1, characterized in that: The S2 smelting process involves using an electric arc furnace for the rolling mill, vacuum smelting of high-quality molten steel in a ladle refining furnace, blowing argon gas throughout the process to create foamy white slag, tapping the steel at a liquidus temperature of 80℃-120℃, and then calming it for 6-8 minutes before casting.

3. A process for the manufacture of a tool steel roll for rolling the frame of a rolled product magnetic pole steel, as claimed in claim 1, characterized in that: The S3 special heat treatment includes the following steps: S11, high-temperature diffusion annealing, heating the high-alloy steel rolled magnetic pole steel finished roll to 150℃-250℃ above AC3 and holding at 25mm / h. The purpose of diffusion treatment is to eliminate the presence of dendritic water crystals and alloy composition segregation during roll solidification, so that the atoms of alloy elements can diffuse fully and obtain a uniform austenitic structure; S22, then performing spheroidizing annealing treatment to improve the cutting performance of the roll and prepare the structure for subsequent quenching treatment. The spheroidizing treatment temperature is slightly higher than the AC1 critical point. If the temperature is too low, the required spheroidizing time will be too long. If the temperature is too high, granular pearlite with varying particle size will appear; S33, then normalizing to 940℃-960℃ and holding for a certain time, followed by spray quenching, and tempering when the roll temperature reaches 430℃-450℃.

4. A process for the manufacture of a tool steel roll for rolling the frame of a rolled product magnetic pole steel, as claimed in claim 1, characterized in that: The S4 roll test results are as follows: fine-grained metallic carbides are uniformly distributed; the roll surface hardness is 70-75 HSD; the hardness difference from the working layer to the bottom of the groove is ≤1.5 HSD; and the tensile strength is ≥750 MPa. The metallographic matrix is ​​composed of fine-grained metallic carbides + tempered sorbite + bainite + martensite.

5. A tool steel roll produced by the manufacturing process of claim 1, wherein: It includes an upper roller and a lower roller arranged horizontally. The middle of the upper roller and the middle of the lower roller are respectively provided with a first working section and a second working section. The first working section has an annular stepped groove, and the second working section has an arc-shaped protrusion. The arc-shaped protrusion is embedded in the annular stepped groove to form the cross-section of the magnetic pole steel.

6. A tool steel roll for rolling a finished magnetic pole steel cage according to claim 5, characterized in that: Tapered bearing stops are provided at both ends of the first working section and both ends of the second working section.

7. A tool steel roll for rolling a finished magnetic pole steel cage according to claim 6, characterized in that: One end of the tapered bearing stop is provided with a flat square transmission end.

8. A tool steel roll for rolling finished magnetic pole steel frames according to claim 6, characterized in that: The other end of the tapered bearing stop is provided with a columnar connecting section.

9. A tool steel roll for rolling a finished magnetic pole steel cage according to claim 8, characterized in that: One end of the columnar connecting section is vertically provided with a threaded lifting hole.

10. A tool steel roll for rolling finished magnetic pole steel frames according to claim 8, characterized in that: The columnar connecting section is provided with an annular groove.

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