Preparation method of composite cold roll and outer layer material

Abstract

The invention discloses a preparation method and an outer-layer material of a composite cold roll, and belongs to the technical field of rolls, and the preparation method comprises the following steps: S1, preparing steel raw materials according to chemical components and weight percentage contents in the outer-layer material of the composite cold roll, and preparing an outer-layer steel ingot according to a smelting procedure production process; s2, the outer-layer steel ingot is manufactured into an outer-layer roller blank according to the forging procedure production technology, and a mandrel roller blank is manufactured according to the mandrel steel ingot according to the forging procedure production technology; s3, the outer-layer roller blank and the mandrel roller blank of the composite cold roller are combined, and a composite cold roller blank is obtained; and S4, the roller blank is machined, and the composite cold roller is obtained. The composite cold roll has good hardness retentivity, structure uniformity and manufacturability, meanwhile, the abrasion resistance, obdurability and structure uniformity of the working layer of the composite cold roll are improved, the comprehensive use effect of the composite cold roll in the whole service period is improved, the steel rolling production efficiency is improved, and the production cost is reduced. And the consumption of the outer layer of the composite cold roll is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of rolling rolls, and particularly relates to a preparation method of a composite cold rolling roll and an outer layer material thereof. Background Art

[0002] Modern cold rolling mills are developing towards high efficiency and high precision, aiming to roll cold rolled strip products with high precision, high strength, and high surface quality, and achieve lower operation and maintenance costs. The cold rolling roll is a direct process for strip forming. The wear resistance of the outer layer of the roll body has a direct and important influence on the shape control of the cold rolled strip during the rolling process, the rolling speed, and the surface quality of the strip. Therefore, it is required that the cold rolling roll has high hardness, relative wear resistance, and tissue stability. Almost all modern rolling mills use cold rolling rolls manufactured by integral forging. The material has been gradually upgraded from Cr3 and Cr5 to semi-high speed steel to improve indicators such as strength and wear resistance. However, at present, when the alloy element content of the integrally forged cold rolling roll is increased to more than semi-high speed steel, the manufacturing difficulty increases and the cost increases, and it is difficult to fully exert the value of alloy elements, mainly manifested as low hardness after high temperature tempering, difficult deformation during forging, easy cracking, and uneven tissue. The fundamental reason is that the material is high and the ingot type of the steel ingot is large, and it is difficult to solve the problems of segregation and coarse tissue. Therefore, the composite roll manufacturing technology has gradually developed. Among them, the working layer of the forged composite roll has good performance and high comprehensive strength and toughness. However, due to the large material differences, it is very important to design the outer layer material to ensure both the improvement of the working layer performance and the composite success rate.

[0003] However, the existing outer layer materials of composite cold rolling rolls cannot have good effects in improving the hardness retention ability, wear resistance, and tissue uniformity of the working layer. Summary of the Invention

[0004] In order to solve the problem that the existing outer layer materials of composite cold rolling rolls cannot have good effects in improving the hardness retention ability, wear resistance, and tissue uniformity of the working layer. The present invention provides a preparation method of a composite cold rolling roll and an outer layer material thereof, and provides an outer layer material of a composite cold rolling roll with higher service performance and higher composite success rate.

[0005] The technical solution adopted by the preparation method of a composite cold rolling roll and an outer layer material thereof in the present invention is as follows:

[0006] An outer layer material of a composite cold rolling roll, wherein the chemical components and weight percentage contents in the outer layer material of the composite cold rolling roll are:

[0007] C 0.80% - 1.10%, Si 0.60% - 1.20%, Mn 0.40% - 0.80%, Cr 5.00% - 7.00%, Ni 0.20% - 0.60%, Mo 1.00% - 2.00%, V 0.50% - 1.00%, P ≤ 0.015%; S ≤ 0.015%; the balance is Fe and inevitable impurities.

[0008] A preparation method of a composite cold rolling roll, using the outer layer material of the above-mentioned composite cold rolling roll, includes the following steps:

[0009] S1. Configure steel raw materials according to the chemical components and weight percentage contents in the outer layer material of the composite cold rolling roll, and obtain an outer layer ingot according to the production process of the smelting process; and configure steel raw materials according to the chemical components and weight percentage contents of the composite cold rolling roll mandrel, and obtain a mandrel ingot according to the production process of the smelting process.

[0010] S2. Obtain an outer layer roll blank from the outer layer ingot according to the production process of the forging process, and obtain a mandrel roll blank from the mandrel ingot according to the production process of the forging process.

[0011] S3. Combine the outer layer roll blank and the mandrel roll blank of the composite cold rolling roll to obtain a composite cold rolling roll blank.

[0012] S4. Process and detect the roll blank to obtain a composite cold rolling roll.

[0013] A further improvement of the above technical solution of the present invention lies in that: the specific steps for obtaining the outer layer ingot according to the production process of the smelting process in step S1 include:

[0014] S1.1. Smelt the outer layer material of the composite cold rolling roll using an electric arc furnace and an LF refining furnace, and analyze the chemical components and weight percentage contents of the molten steel in the refining furnace.

[0015] S1.2. Conduct vacuum degassing on the qualified molten steel, and vacuum-cast it into an electrode ingot, and then perform electroslag remelting under gas protection.

[0016] A further improvement of the above technical solution of the present invention lies in that: after the degassing of the molten steel, [H] < 1.0 ppm, [O] < 10 ppm, and [N] < 50 ppm inside.

[0017] A further improvement of the above technical solution of the present invention lies in that: the specific production process of the forging process in step S2 includes:

[0018] S2.1. Adopt the fine grain treatment technology to forge into a sleeve forging blank.

[0019] S2.2. Adopt a 42CrMo continuous casting billet to forge into a mandrel forging blank.

[0020] S2.3. Subject the sleeve forging blank and the mandrel forging blank to post-forging heat treatment, and then perform turning to obtain the outer layer roll blank and the mandrel roll blank.

[0021] A further improvement of the above technical solution of the present invention is that: in step S3, after the outer layer roll blank and the mandrel roll blank are combined to form a bimetallic composite structure, the bimetallic composite structure is forged to form a composite cold rolling roll blank.

[0022] A further improvement of the above technical solution of the present invention is that: in step S4, the composite cold rolling roll is obtained according to the induction heat treatment process and the finished product processing process of the cold rolling roll, and then the interface composite strength, the relative wear resistance of the outer layer, the hardness of the outer layer, etc. of the composite interface sample are detected.

[0023] Due to the adoption of the above technical solution, the technical progress achieved by the present invention includes:

[0024] The composite cold rolling roll in the present invention has good hardness retention, tissue uniformity and good processability. At the same time, the wear resistance, strength and toughness and tissue uniformity of the working layer of the composite cold rolling roll are improved, so that the comprehensive use effect during the entire service period of the composite cold rolling roll is improved, the rolling production efficiency is increased, and the consumption of the outer layer of the composite cold rolling roll is reduced.

[0025] The present invention has made improvements in the chemical components and weight percentage contents of the conventional semi-high speed steel material cold rolling roll. Compared with the traditional semi-high speed steel material, the present invention increases the C, Ni, Mo and V alloy elements in the outer layer material of the composite cold rolling roll, but does not reduce the smelting, forging and heat treatment processability of the outer layer material of the composite cold rolling roll. Compared with the traditional integral forging, the tissue uniformity and wear resistance of the outer layer material of the forged composite cold rolling roll in the present invention are higher. Specific Embodiments

[0026] To make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. In the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts of the present invention.

[0027] The present invention discloses an outer layer material of a composite cold rolling roll, and the chemical components and weight percentage contents in the outer layer material of the composite cold rolling roll are:

[0028] C 0.80% - 1.10%, Si 0.60% - 1.20%, Mn 0.40% - 0.80%, Cr 5.00% - 7.00%, Ni 0.20% - 0.60%, Mo 1.00% - 2.00%, V 0.50% - 1.00%, P≤0.015%; S≤0.015%; the rest are Fe and unavoidable impurities.

[0029] The chemical components and their weight percentage contents in the outer layer material of the above-mentioned composite cold rolling roll are further preferably: C 0.95% - 1.10%, Si 0.80% - 1.00%, Mn 0.45% - 0.60%, Cr 6.20% - 7.00%, Ni 0.20% - 0.60%, Mo 1.50% - 2.00%, V 0.50 - 0.80%, P ≤ 0.015%; S ≤ 0.005%; the balance is Fe and unavoidable impurities.

[0030] The present invention also discloses a preparation method of a composite cold rolling roll, which uses the outer layer material of the above-mentioned composite cold rolling roll and includes the following steps:

[0031] S1. Configure steel raw materials according to the chemical components and their weight percentage contents in the outer layer material of the composite cold rolling roll, and produce an outer layer ingot according to the production process of the smelting process; and configure steel raw materials according to the chemical components and their weight percentage contents of the composite cold rolling roll mandrel, and produce a mandrel ingot according to the production process of the smelting process.

[0032] The specific steps of producing the outer layer ingot according to the production process of the smelting process in the above step S1 include the following steps:

[0033] S1.1. Use the outer layer material of the above-mentioned composite cold rolling roll, smelt the outer layer material of the composite cold rolling roll with an electric arc furnace and an LF refining furnace, and test the chemical components and their weight percentage contents of the molten steel in the refining furnace.

[0034] S1.2. Conduct vacuum degassing on the qualified molten steel after testing, and die-cast it into an electrode ingot under vacuum, and then conduct electroslag remelting under gas protection. Since the content of alloy elements such as Cr and Mo in the molten steel is high and the segregation tendency is large, in order to improve the composite processability and ensure the outer layer performance, increase the vacuum intensity during the degassing process and extend the vacuum time to achieve the purpose of improving the degassing effect, so that [H] < 1.0 ppm, [O] < 10 ppm, [N] < 50 ppm inside the molten steel after degassing.

[0035] S2. Produce an outer layer roll blank from the outer layer ingot according to the production process of the forging process, and produce a mandrel roll blank from the mandrel ingot according to the production process of the forging process.

[0036] The production process of the forging process in the above step S2 specifically includes,

[0037] S2.1. Adopt the fine grain treatment technology to forge into a sleeve forging blank;

[0038] S2.2. Forge a 42CrMo continuous casting blank into a mandrel forging blank;

[0039] S2.3. Conduct post-forging heat treatment on the sleeve forging blank and the mandrel forging blank, and then conduct turning processing to obtain the outer layer roll blank and the mandrel roll blank.

[0040] Specifically, the outer ingot is heated to the forging temperature in a trolley furnace at 1100 - 1300 °C, held for 20 - 30 h, and then transferred to an 80 MN hydraulic press for forging. Through upsetting, drawing, and hole expanding forging, the outer ingot is made into a sleeve forging blank. The sleeve forging blank is subjected to post-forging heat treatment, and finally, turning processing is carried out to obtain the outer roll blank.

[0041] Among them, the specific process of post-forging heat treatment is to heat the sleeve forging blank to 780 - 880 °C, hold for 10 - 15 h, then slowly cool to 680 - 720 °C, hold for 20 - 30 h, and then perform annealing treatment.

[0042] The mandrel is forged from a 42CrMo continuous forging blank into a mandrel forging blank. The mandrel forging blank is subjected to post-forging heat treatment, and finally, turning processing is carried out to obtain the outer roll blank and the mandrel. The post-forging heat treatment process of the mandrel forging blank is the same as that of the sleeve forging blank.

[0043] S3. After combining the outer roll blank and the mandrel roll blank of the composite cold rolling roll to form a bimetallic composite structure, the bimetallic composite structure is forged to form a composite cold rolling roll forging blank.

[0044] The specific process of combining the above-mentioned outer roll blank and the mandrel roll blank of the composite cold rolling roll is as follows: The outer roll blank and the mandrel roll blank are processed to have a 0 clearance, the surfaces are cleaned with a special cleaner, then the outer roll blank and the mandrel roll blank are assembled together, and finally, a special sealing welding technology is used to prepare the composite interface into a vacuum state. The combined roll blank is heated in a trolley furnace at a heating temperature of 1150 - 1250 °C, held for 20 - 30 h, and then transferred to an 80 MN hydraulic press for forging. Through a special normal stress technology for forging, the outer roll blank and the mandrel roll blank are prepared into a metallurgical composite bimetallic composite cold rolling roll forging blank under high temperature and compressive stress.

[0045] S4. The roll blank is processed and tested to obtain a composite cold rolling roll. Specifically, the composite cold rolling roll is prepared according to the induction heat treatment process and finished product processing process of the cold rolling roll, and then the composite interface sample is tested for interface composite strength, outer relative wear resistance, outer hardness, etc.

[0046] Example 1

[0047] The preparation method of the composite cold rolling roll in this example includes the following steps:

[0048] S1. Configure steel raw materials according to the chemical components and weight percentage contents in the outer layer material of the composite cold rolling roll, and obtain the outer ingot according to the production process of the smelting process; and configure steel raw materials according to the chemical components and weight percentage contents of the mandrel of the composite cold rolling roll, and obtain the mandrel ingot according to the production process of the smelting process.

[0049] In step S1 above, the outer steel ingot produced according to the smelting process production technology specifically includes the following steps:

[0050] S1.1. Use the outer layer material of the above-mentioned composite cold rolling roll, smelt the outer layer material of the composite cold rolling roll in an electric arc furnace and an LF refining furnace, and test the chemical components and weight percentage content of the molten steel in the refining furnace.

[0051] S1.2. Vacuum degas the molten steel after passing the test, and then die-cast it into an electrode ingot under vacuum, and then perform electroslag remelting under gas protection. Since the content of alloying elements such as Cr and Mo in the molten steel is high and the segregation tendency is large, in order to improve the composite processability and ensure the outer layer performance, the degassing effect should be improved during the degassing process, so that the internal H < 1.0 ppm, O < 10 ppm, and N < 50 ppm after the molten steel is degassed.

[0052] In this embodiment, the chemical components and weight percentage content in the outer layer material of the composite cold rolling roll in step S1 are shown in Table 1 below, and the rest are Fe and inevitable impurities.

[0053] Table 1 Detection results of chemical composition and gas content of the outer layer material

[0054] C Si Mn P S Cr Ni Mo V

H

O

N

[0055] S2. Produce an outer layer roll blank from the outer layer steel ingot according to the forging process production technology, and produce a mandrel roll blank from the mandrel steel ingot according to the forging process production technology.

[0056] Specifically, the outer layer steel ingot is heated to the forging temperature in a trolley furnace at 1300 °C, kept warm for 20 h, and then transferred to an 80 MN hydraulic press for forging. Through upsetting, drawing out, and hole expanding forging, the outer layer steel ingot is made into a sleeve forging blank. The sleeve forging blank is subjected to post-forging heat treatment, and finally turning processing is carried out to obtain the outer layer roll blank.

[0057] The 42CrMo continuous casting billet is heated to the forging temperature in a trolley furnace at 1300 °C, kept warm for 20 h, and then transferred to an 80 MN hydraulic press for forging. Through upsetting, drawing out, and hole expanding forging, the steel ingot is made into a mandrel forging blank. The mandrel forging blank is subjected to post-forging heat treatment, and finally turning processing is carried out to obtain the mandrel roll blank.

[0058] Among them, the specific process of the post-forging heat treatment is to heat the sleeve forging blank to 880 °C, keep warm for 15 h, then slowly cool it to 720 °C, keep warm for 30 h, and then perform annealing treatment.

[0059] S3. Combine the outer layer roll blank and the mandrel roll blank of the composite cold rolling roll to form a bimetallic composite structure, and then forge the bimetallic composite structure to form a composite cold rolling roll blank.

[0060] The specific process of combining the above-mentioned outer layer roll blank and the core shaft roll blank of the composite cold rolling roll is as follows: The outer layer roll blank and the core shaft roll blank are processed to an interference fit of +0.05 - 0.10 mm. The inner circular surface of the outer layer roll blank and the outer circular surface of the core shaft roll blank are cleaned with a special cleaner. Then, at room temperature, the outer layer roll blank and the core shaft roll blank are assembled together. Finally, a special sealing welding technology is used to prepare the composite interface into a vacuum state. The combined roll blank is heated in a trolley furnace to 1250°C ± 50°C, held for 20 minutes, and then transferred to an 80MN hydraulic press for forging. Through a special normal stress technology for forging, according to the drawing requirements, the outer layer roll blank and the core shaft roll blank are prepared into a metallurgical composite bimetallic composite cold rolling roll blank under high temperature and compressive stress.

[0061] S4. Process and detect the roll blank to obtain the composite cold rolling roll. Specifically, the composite cold rolling roll blank is subjected to induction quenching heat treatment. The surface temperature is heated to 1060°C ± 10°C on a quenching machine tool, held for 20 minutes, and then transferred to a spray quenching machine tool for cooling. The surface cooling rate is controlled at an average of 0.35 - 0.50°C / s, cooled for 35 minutes, and continuously tempered 2 times in the temperature range of 500°C ± 50°C, with each tempering holding time of 25 hours. Then it is processed to the detection state. The surface hardness of the roll body is detected using a D-type mechanical Shore hardness tester, and the test result value unit is HSD. The metallographic structure at different depth positions of the working layer is detected. At the same time, a sample is taken on one side of the roll body to detect the relative wear resistance of the outer layer material. The detection results are shown in Tables 2, 3, and 4 below.

[0062] Table 2 Detection Results of Outer Layer Hardness and Structure

[0063]

[0064]

[0065] Remark: The tempered martensite here is fine needle and hidden needle martensite.

[0066] Table 3 Detection Results of Outer Layer Hardness and Structure of the Roll Made of Cr5 Material

[0067] Depth from surface (mm) Hardness (HSD) Metallographic structure 0 93 Tempered martensite + carbide 10 93 Tempered martensite + carbide 20 91 Tempered martensite + carbide 30 88 Tempered martensite + carbide 40 82 Tempered martensite + carbide + a small amount of pearlite

[0068] Remark: The tempered martensite here is fine needle and hidden needle martensite.

[0069] Table 4 Detection Results of Outer Layer Relative Wear Resistance

[0070] Depth from surface (mm) Relative wear resistance Relative wear resistance of Cr5 material 0 9.5 4.1 10 9.9 4.3 20 9.4 4.5 30 9.3 3.8 40 9.0 2.9

[0071] Remark: The relative wear resistance here is the relative wear resistance with GGr15, and the hardness of the accompanying sample is HRC63 ± 1HRC.

[0072] According to the detection results in Table 2, Table 3 and Table 4 above, it can be concluded that the hardness, tissue uniformity and wear resistance of the composite cold rolling roll prepared by using the outer layer material and method of the present invention are all improved.

[0073] In the above embodiments, the present invention provides a preparation method and an outer layer material for a composite cold rolling roll. The composite cold rolling roll in the present invention has good hardness retention, tissue uniformity and good processability. At the same time, the wear resistance, strength and toughness and tissue uniformity of the working layer of the composite cold rolling roll are improved, so that the comprehensive use effect during the entire service life of the composite cold rolling roll is improved, the steel rolling production efficiency is increased, and the consumption of the outer layer of the composite cold rolling roll is reduced.

[0074] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various variations and improvements made by those of ordinary skill in the art to the technical solution of the present invention should fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. An outer layer material of a composite cold rolling roll, characterized in that: The chemical components and their weight percentage contents in the outer layer material of the composite cold rolling roll are as follows: C 0.80% - 1.10%, Si 0.60% - 1.20%, Mn 0.40% - 0.80%, Cr 5.00% - 7.00%, Ni 0.20% - 0.60%, Mo 1.00% - 2.00%, V 0.50% - 1.00%, P ≤ 0.015%; S ≤ 0.015%; The balance is Fe and unavoidable impurities.

2. A preparation method of a composite cold rolling roll, characterized in that: Using the outer layer material of the composite cold rolling roll described in Claim 1, the following steps are included: S1. Configure steel raw materials according to the chemical components and their weight percentage contents in the outer layer material of the composite cold rolling roll, and obtain the outer layer ingot according to the production process of the smelting process; and configure steel raw materials according to the chemical components and their weight percentage contents of the composite cold rolling roll mandrel, and obtain the mandrel ingot according to the production process of the smelting process. S2. Obtain the outer layer roll blank from the outer layer ingot according to the production process of the forging process, and obtain the mandrel roll blank from the mandrel ingot according to the production process of the forging process. S3. Combine the outer layer roll blank and the mandrel roll blank of the composite cold rolling roll to obtain the composite cold rolling roll blank. S4. Process and inspect the roll blank to obtain the composite cold rolling roll.

3. The preparation method of a composite cold rolling roll according to claim 2, characterized in that: The specific steps for obtaining the outer layer ingot according to the production process of the smelting process in step S1 include: S1.

1. Smelt the outer layer material of the composite cold rolling roll using an electric arc furnace and an LF refining furnace, and analyze the chemical components and their weight percentage contents of the molten steel in the refining furnace. S1.

2. Conduct vacuum degassing on the qualified molten steel after analysis, then vacuum-cast it into an electrode ingot, and then perform electroslag remelting under gas protection.

4. The preparation method of a composite cold rolling roll according to claim 3, characterized in that: After degassing the molten steel, 【H】< 1.0 ppm, 【O】< 10 ppm, and 【N】< 50 ppm inside.

5. The preparation method of a composite cold rolling roll according to claim 2, characterized in that: The specific production process of the forging process in step S2 includes: S2.

1. Use the fine grain treatment technology to forge it into a sleeve forging blank. S2.

2. Use 42CrMo continuous casting billet to forge into a mandrel forging blank. S2.

3. Perform post-forging heat treatment on the sleeve forging blank and the mandrel forging blank, and then perform turning processing to obtain the outer layer roll blank and the mandrel roll blank.

6. The preparation method of a composite cold rolling roll according to claim 2, wherein: After combining the outer layer roll blank and the mandrel roll blank in step S3, a bimetal composite structure is formed, and the bimetal composite structure is forged to form the composite cold rolling roll blank.

7. The preparation method of a composite cold rolling roll according to claim 2, characterized in that: In step S4, the composite cold rolling roll is obtained according to the induction heat treatment process and the finished product processing process of the cold rolling roll, and then the interface composite strength, relative wear resistance of the outer layer, hardness of the outer layer, etc. of the composite interface sample are detected.

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