Method for manufacturing a cold rolling roller for shot peening

Abstract

The application discloses a method for manufacturing a cold rolling roller for shot blasting, and belongs to the technical field of roller manufacturing. The method comprises the following steps: refining a steel raw material by using an LF / VD refining furnace, removing impurities by using a reduction method, removing gas in molten steel by vacuumizing through VD, pouring into an electrode ingot, obtaining an electroslag ingot with high purity, uniform components and fine grains by electroslag remelting the electrode ingot, heat treating the electroslag ingot before forging, and obtaining a roller blank by forging and annealing; the roller blank is subjected to spheroidizing annealing and quenching and tempering treatment, the roller blank after the quenching and tempering treatment is subjected to tempering, and after the tempering is completed, the roller blank is processed according to the final heat treatment size; and after the final heat treatment, the cold rolling roller for shot blasting is manufactured. The application can manufacture a rolling roller with refined matrix structure and uniform surface quality, and effectively reduces the problem of strip color difference on the surface of the rolling roller after shot blasting.

Description

Technical Field

[0001] This invention relates to the field of roll manufacturing technology, and in particular to a method for manufacturing cold rolls for shot peening and texturing. Background Technology

[0002] With the continuous development of industries such as home appliances and automobiles, the requirements for products are getting higher and higher. Therefore, the requirements for the surface quality, stability and consistency of the sheet materials used are also constantly increasing. As the rollers that are in direct contact with the sheet surface, they have a direct impact on the surface quality of the sheet material. The quality of the rollers can directly affect the surface quality of the sheet material.

[0003] Therefore, some manufacturers use shot peening and chrome plating techniques to maintain the surface quality of rolls. These techniques have high requirements for the original surface quality of the rolls, and some banded color difference defects are prone to appear after the rolls are roughened, which makes the roughened rolls unusable for rolling. Therefore, there is a need for a manufacturing method for rolls that can be shot peening and roughened. The manufactured rolls can effectively improve the surface quality of the rolls and reduce some color difference problems caused by the quality of the rolls after roughening. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for manufacturing cold rolling rolls for shot peening texturing, which can effectively improve the surface quality of the rolls and reduce some color difference problems caused by the quality of the rolls after texturing.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for manufacturing cold rolling rolls for shot peening, comprising the following steps:

[0006] Step 1: Steel making. The steel raw materials are refined in an LF / VD refining furnace. Impurities are removed by reduction, and then the gas in the molten steel is removed by vacuuming in a VD furnace and cast into electrode ingots.

[0007] Step 2: Electroslag remelting the electrode ingot yields an electroslag ingot with high steel purity, uniform composition, and fine grains.

[0008] Step 3: The electroslag ingot is heated at high temperature to redistribute and homogenize the alloy components in the electroslag ingot, and then forged and annealed to obtain the roll blank.

[0009] Step 4: Heat treat the roll blank to obtain refined grains and uniformly distributed spherical or granular carbides, thereby improving the mechanical properties of the roll matrix;

[0010] Step 5: Process the heat-treated roll blank according to the final heat-treated dimensions;

[0011] Step 6: Perform final heat treatment on the processed roll blank, and then finish it according to the required dimensions to produce a cold rolling roll for shot peening.

[0012] A further improvement to the technical solution of this invention is that the chemical composition and weight percentage of the steel raw material in step 1 are as follows: C 0.7-0.90%; Si 0.50-0.70%; Mn 0.50-0.70%; Cr 4.8-5.2%; Mo 0.20-0.50%; Ni ≤0.30%; S ≤0.025%; P ≤0.025%.

[0013] A further improvement to the technical solution of the present invention is that the ratio of the diameter of the electrode ingot to that of the electroslag crystallizer in step 2 is required to be no greater than 1.3.

[0014] A further improvement to the technical solution of the present invention is that the electroslag remelting melting rate in step 2 is controlled at 450-550 kg / min.

[0015] A further improvement to the technical solution of the present invention is that: in step 3, the high-temperature heating treatment is specifically carried out at a heating temperature of 1200-1250℃, a holding time of 10-15h, and a forging ratio of 3 or greater during the forging process.

[0016] A further improvement of the technical solution of the present invention is that the heat treatment in step 4 is specifically to perform normalizing heat treatment at 1020-1060℃ for 20-30h followed by spheroidizing annealing heat treatment at 820℃ for 20h.

[0017] The technological advancements achieved by this invention, due to the adoption of the above-mentioned technical solutions, are as follows: Electroslag remelting of electrode ingots yields electroslag ingots with high steel purity, uniform composition, and fine grains. High-temperature heating of the electroslag ingots redistributes and homogenizes the alloy components, providing a foundation for subsequent roll quality improvement. Through reasonable elemental proportions and appropriate electroslag remelting, heat treatment, and forging technologies, combined with final heat treatment and finishing, the matrix structure of the rolls is refined, improving the surface uniformity and effectively reducing the banded color difference problem on the roll surface after shot peening. This improves the quality of the rolls after shot peening. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to embodiments:

[0019] A method for manufacturing cold rolling rolls for shot peening includes the following specific steps:

[0020] Step 1: Steel Refining. The steel raw materials are refined using an LF / VD refining furnace. The chemical composition and weight percentage of the steel raw materials are: C 0.7-0.90%; Si 0.50-0.70%; Mn 0.50-0.70%; Cr 4.8-5.2%; Mo 0.20-0.50%; Ni≤0.30%; S≤0.025%; P≤0.025%. Impurities are removed by reduction, and then gases in the molten steel are removed by vacuum extraction using a VD furnace before casting into electrode ingots.

[0021] Step 2: Electroslag remelting the electrode ingot to obtain an electroslag ingot with high steel purity, uniform composition and fine grains. The ratio of the diameter of the electrode ingot to that of the electroslag crystallizer should not exceed 1.3, and the electroslag remelting rate should be controlled at 450-550 kg / min.

[0022] Step 3: The electroslag ingot is subjected to high-temperature heating treatment to redistribute and homogenize the alloy components in the electroslag ingot. The high-temperature heating treatment is specifically carried out at a heating temperature of 1200-1250℃ and a holding time of 10-15h. Then, it is forged with a forging ratio of ≥3 and then annealed to obtain the roll blank.

[0023] Step 4: Heat treat the roll blank. The roll blank is subjected to normalizing heat treatment at 1020-1060℃ for 20-30 hours and spheroidizing annealing heat treatment at 820℃ for 20 hours to obtain refined grains and uniformly distributed spherical or granular carbides, thereby improving the mechanical properties of the roll matrix.

[0024] Step 5: Process the heat-treated roll blank according to the final heat-treated dimensions;

[0025] Step 6: Perform final heat treatment on the processed roll blank, and then finish it according to the required dimensions to produce a cold rolling roll for shot peening.

[0026] Example 1:

[0027] In this embodiment, the chemical composition and content of the steel were selected and cast into steel billets. The table below shows the chemical composition of the steel; (the unit in the table is wt%, the rest is Fe and a small amount of impurities).

[0028] C To Mn Cr Know In P S 0.82 0.35 0.63 4.95 0.31 0.11 0.017 0.002

[0029] The steel was refined using the chemical composition and weight percentages listed in the table above. It was then refined in an LF / VD refining furnace, with impurities removed by reduction. Gas was removed from the molten steel by vacuum extraction using VD, and the steel was cast into electrode ingots. The electrode ingot dimensions were φ500*3500mm. The crystallizer used for electroslag remelting was φ645*3000mm, with a diameter ratio of 1.28. The average melting rate during the electroslag process was 580kg / min. The electroslag ingot was heated to 1220℃ and held for 11 hours. After forging, it was held at 1030℃ for 23 hours, followed by mist cooling and spheroidizing annealing at 820℃ for 20 hours to obtain a roll blank. After processing and final heat treatment, the roll blank was obtained as a shot-peened, roughened cold-rolled roll.

[0030] By using the chemical composition and content of the steel and the heat treatment process in the table above, the cold rolling rolls for shot peening and texturing are manufactured. Their hardness meets the user's requirements, and the ultrasonic flaw detection meets the GB / T13314-2008 standard. After shot peening and texturing, no banded color difference defects are seen on the roll surface, and the surface quality meets the requirements for rolling high-quality plates.

[0031] This invention can manufacture rolls with fine matrix structure and uniform surface quality, which can effectively reduce the problem of banded color difference on the roll surface after shot peening and improve the quality of rolls after subsequent shot peening and ensure the performance requirements of the sheet metal in production.

[0032] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for manufacturing cold rolling rolls for shot peening, characterized in that: The steps include the following: Step 1: Steel Refining. The steel raw materials are refined in an LF / VD refining furnace. Impurities are removed using a reduction method, and then the molten steel is vacuum-treated using a VD furnace to remove gases before being cast into electrode ingots. The chemical composition and weight percentage of the steel raw materials in Step 1 are as follows: C 0.7~0.90%; Si 0.50~0.70%; Mn 0.50~0.70%; Cr 4.8~5.2%; Mo 0.20~0.50%; Ni ≤0.30%; S≤0.025%; P ≤0.025%. Step 2: Electroslag remelting the electrode ingot to obtain an electroslag ingot with high steel purity, uniform composition, and fine grains; the ratio of the diameter of the electrode ingot to the diameter of the electroslag crystallizer in Step 2 should not exceed 1.3; the electroslag remelting melting rate in Step 2 should be controlled at 450~550 kg / min. Step 3: The electroslag ingot is heated at high temperature to redistribute and homogenize the alloy components in the electroslag ingot, and then forged and annealed to obtain the roll blank; the high temperature heating treatment in step 3 is specifically a heating temperature of 1200~1250℃, a holding time of 10~15h, and a forging ratio of greater than or equal to 3 during the forging process. Step 4: The roll blank is heat-treated to obtain refined grains and uniformly distributed spherical or granular carbides, thereby improving the mechanical properties of the roll matrix. Specifically, the heat treatment in Step 4 involves normalizing the roll blank at 1020~1060℃ for 20~30 hours, followed by spheroidizing annealing at 820℃ for 20 hours. Step 5: Process the heat-treated roll blank according to the final heat-treated dimensions; Step 6: Perform final heat treatment on the processed roll blank, and then finish it according to the required dimensions to produce a cold rolling roll for shot peening.