Profile hot roll composite material, multifunctional coating, preparation method and application thereof

Abstract

The invention relates to the technical field of surfaces, in particular to a sectional material hot roller composite material, a multifunctional coating, a preparation method and application of the multifunctional coating, a composite material system can be two components or three components, the performance of the coating can be regulated and controlled by selecting proper components and adjusting the proportion of the different components, and the coating can be applied to the field of surface treatment. Therefore, the requirements of different production lines on roller surface functions are met; the invention further provides a preparation method of the composite powder corresponding to the composite material system, a preparation method for depositing the composite powder on the surface of a profile hot roller to form a multifunctional coating and application of the multifunctional coating in a profile steel hot rolling production line. The multifunctional coating provided by the invention has multiple functions of wear resistance, friction reduction, corrosion resistance, adhesion resistance, thermal fatigue resistance and the like, and can greatly prolong the single steel passing amount of the roller, reduce the post-processing amount of the roller and increase the repairable frequency of the roller, so that the service life of the roller is greatly prolonged, and the total steel passing amount of the roller is greatly increased.

Description

Technical Field

[0001] The invention relates to the field of surface technology, and in particular to a profile hot rolling roller composite material and a multifunctional coating, a preparation method and applications thereof. Background Art

[0002] Section steel is one of the four major types of steel, widely used in construction projects, bridge projects, etc., and occupies a large position in the national economy. There are many ways to produce section steel, among which hot-rolled section steel has large production scale and high efficiency, and has become the main way of section steel production.

[0003] At present, the materials of hot rolling rollers for profiles are generally cast steel, ductile iron, high-speed steel, etc. Since the hot-rolled (rod) profile rollers are in contact with high-temperature steel billets during service, they are subjected to high rolling force loads and large friction, and the rollers usually fail quickly in the form of wear, cracking, and steel sticking. Taking the rollers of the V8 stand of the rod and wire production line of a domestic steel plant as an example, the rollers of this stand usually use high-speed steel as the base material, and are used directly after the specified hole shape is turned, without any strengthening treatment on the surface; according to the tracking of the actual production process, after the above-mentioned rollers passed about 8,000 tons of steel, a large number of thermal fatigue cracks appeared on the roller surface, and the cracks were deep. Since the rollers are repaired by reducing the diameter, they need to be completely turned to remove the previous cracks before they can continue to be used in the subsequent machining process, so the processing volume is also large and the rollers can be used less frequently.

[0004] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that deep thermal fatigue cracks appear on the roller surface after passing steel, which leads to a large amount of subsequent processing and a small number of roller usable times. A composite material for a profile hot rolling roller and a multifunctional coating, a preparation method and application thereof are provided.

[0006] In order to achieve the above-mentioned purpose, the present invention discloses a preparation method of a profile hot rolling roller composite material and a multifunctional coating, wherein the composite material is a component A / B compound or an A / B / C compound, wherein the component A is Cr3C2-25NiCr, the component B is NiCr-25MoS2, and the component C is NiCr.

[0007] When the components A / B are compounded, the mass ratio of component A to component B is 1-4:1-5.

[0008] When the components A / B / C are compounded, the mass ratio of component A, component B, and component C is 1-4:1-5:1-5.

[0009] The composite material has a particle size of 10 to 150 μm.

[0010] The particle size of the composite material is preferably 15 to 75 μm.

[0011] Since the profile rollers are subjected to high loads during service and are in contact with high-temperature steel billets in a water vapor environment, the rollers usually fail quickly in the form of thermal fatigue, wear, peeling, and steel sticking. A single component is difficult to meet the complex and harsh working conditions of profile steel rollers. By compounding different components, a multifunctional coating that meets the working conditions can be obtained. The applicant has obtained general rules for multifunctional coatings that are generally applicable to the surfaces of various types of steel rollers through research and analysis of various types of steel production lines, compounding of material systems, and long-term practice and summary. The present invention systematically divides various materials that can be used for profile steel roller production lines into three categories. Component A has the characteristics of wear resistance and corrosion resistance, component B has the characteristics of friction reduction, anti-sticking, and heat fatigue resistance, and component C has special functions such as toughening, lubrication, and self-wear. Optionally, component A is various types of metal ceramics and ceramics, component B is specific ceramics, metal ceramics, and metal-coated powders; component C is a specific alloy, ceramic, polymer, and composite powder. For example, for the V8 rack of a steel plant's bar and wire production line described in the present invention, component A is preferably Cr3C2-25NiCr, component B is preferably NiCr-25MoS2, and component C is preferably NiCr.

[0012] The invention also discloses a method for preparing the profile hot rolling roller composite material. The component A / B compounding or A / B / C compounding includes: mechanical mixing, spray granulation, sintering crushing or gas atomization.

[0013] The present invention also discloses a method for preparing a multifunctional coating for a profile hot rolling roller, wherein the profile hot rolling roller composite material is deposited on the roller surface into a multifunctional coating by supersonic flame spraying technology, atmospheric plasma spraying technology or laser cladding technology.

[0014] The invention also discloses a multifunctional coating for a hot rolling roller of a profile obtained by the preparation method, wherein the coating has a thickness of 50 to 1000 μm.

[0015] The invention also discloses a multifunctional coating for a hot rolling roller of a profile obtained by the preparation method, wherein the coating has a thickness of 50 to 150 μm.

[0016] The invention also discloses the application of the multifunctional coating of the hot rolling roller of profiles in a hot rolling production line of profiled steel.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. The material system of the present invention can be a two-component or three-component system, wherein component A has the characteristics of wear resistance and corrosion resistance, component B has the characteristics of friction reduction, anti-sticking, and thermal fatigue resistance, and component C has special functions such as toughening, lubrication, and self-wear. By selecting appropriate components and adjusting the ratio between different components, the performance of the coating can be adjusted to meet the requirements of different production lines for the surface function of the roller;

[0019] 2. The present invention provides a composite coating on the surface of the profile roller that integrates wear resistance, friction reduction, corrosion resistance, anti-sticking and heat fatigue resistance, which greatly extends the single steel passing amount of the roller, reduces the amount of post-processing of the roller, and increases the number of times the roller can be repaired, thereby greatly improving the service life of the roller and the total steel passing amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the metallographic structure of the cross section of the sample in Example 1;

[0021] Figure 2 This is a comparison diagram of the roll surface after rolling 23,000 tons in Example 1;

[0022] Figure 3 This is a comparison diagram of the roll surface after rolling 20,000 tons in Example 2;

[0023] Figure 4 This is a comparison chart of the roller surface conditions after rolling 8,000 tons of comparative example 1. DETAILED DESCRIPTION

[0024] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0025] Example 1

[0026] (1) Component A is Cr3C2-25NiCr, component B is NiCr-25MoS2, component C is NiCr, and the mass ratio of component A, component B, and component C is 4:5:1;

[0027] (2) preparing the composite powder of the formula described in step (1) by mechanical mixing;

[0028] (3) The sample piece was welded to the end of the roll. After the roll and the sample piece were degreased and sanded, a multifunctional coating was deposited on the roll and the sample piece using supersonic flame spraying technology based on the powder in step (2). The supersonic flame spraying process parameters are shown in Table 1. The coating thickness was 150 μm. The metallographic structure of the sample cross section is shown in the attached figure. Figure 1 shown.

[0029] Table 1 High velocity flame spraying process parameters

[0030]

[0031] Example 2

[0032] (1) Component A is Cr3C2-25NiCr, component B is NiCr-25MoS2, and the mass ratio of component A to component B is 4:5.

[0033] (2) preparing the composite powder of the formula described in step (1) by mechanical mixing;

[0034] (3) After the roller surface was degreased and sanded, a multifunctional coating with a thickness of 150 μm was deposited on the roller and the sample surface using supersonic flame spraying technology based on the powder described in step (2). The supersonic flame spraying process parameters are shown in Table 1.

[0035] Comparative Example 1

[0036] Conventional roller surfaces are used without any strengthening treatment.

[0037] The same specifications of bars and wires were rolled in the same V8 stand in Example 1, Example 2 and Comparative Example 1. After Example 1 rolled 23,000 tons, Example 2 rolled 20,000 tons and Comparative Example 1 rolled 8,000 tons, the roll surface was as shown in the figure. Figures 2 to 4 shown.

[0038] From the comparison results, it can be seen that after rolling 23,000 tons, the roller surface of Example 1 is in good condition, the roller surface cracks are few and shallow, the rolling process is normal, and rolling can continue according to the actual conditions of the production line; after rolling 20,000 tons, cracks appeared on the roller surface of Comparative Example 2, and in order to ensure product quality, the rollers were taken offline after comprehensive consideration; and after only rolling 8,000 tons of Comparative Example 1, the roller surface cracks are many and deep, and it is easy to stick to steel during rolling, so the rollers must be taken offline.

[0039] After comparative example 1 rolled 8,000 tons and rolled off the production line, it needed to be turned by 4.0 to 6.0 mm (diameter reduction) before it could be used next time. According to the machining allowance, the roller could be scrapped after 5 to 7 times of diameter reduction (the roller could be reduced by 30 mm at most), and the equivalent amount of steel passing through a single hole was not higher than 56,000 tons. After example 1 rolled 23,000 tons and example 2 rolled off the production line, they could be repaired for the next time after turning less than 2.0 mm (diameter reduction). Therefore, the rollers of examples 1 and 2 could be repaired more than 15 times, and the equivalent amount of steel passing through a single hole was not less than 345,000 tons and 300,000 tons, respectively, which was more than 5 times that of comparative example 1, and the improvement effect was very significant.

[0040] In addition, compared with Example 1, Example 2 did not add toughening components. Although it also achieved a good strengthening effect, during the service process, the roller surface strengthening coating cracked and peeled off due to insufficient toughness, resulting in premature shutdown. It can be seen that the mixing of each component will have a significant impact on the service performance of the coating.

[0041] In summary, the multifunctional coating of the present invention can significantly extend the single steel passing amount of the roller, reduce the amount of post-processing of the roller, and increase the number of times the roller can be repaired, thereby significantly improving the service life of the roller and the total steel passing amount.

[0042] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A composite material for hot rolling rolls of profiles, characterized in that: The composite material is a component A / B compound or an A / B / C compound, wherein the component A is Cr3C2-25NiCr, the component B is NiCr-25MoS2, and the component C is NiCr.

2. A composite material for hot rolling rolls of profiles as claimed in claim 1, characterized in that: When the components A / B are compounded, the mass ratio of component A to component B is 1-4:1-5.

3. The composite material for hot rolling roll of profiles according to claim 1, characterized in that: When the components A / B / C are compounded, the mass ratio of component A, component B, and component C is 1-4:1-5:1-5.

4. The composite material for hot rolling roll of profiles according to claim 1, characterized in that: The composite material has a particle size of 10 to 150 μm.

5. The composite material for hot rolling roll of profiles according to claim 1, characterized in that: The composite material has a particle size of 15 to 75 μm.

6. The method for preparing a composite material of a hot-rolled profile roll according to any one of claims 1 to 5, characterized in that: The methods of compounding components A / B or A / B / C include: mechanical mixing, spray granulation, sintering crushing or gas atomization.

7. A method for preparing a multifunctional coating for a hot rolling roller of a profile, characterized in that: The profile hot rolling roller composite material according to any one of claims 1 to 5 is formed into a multifunctional coating on the roller surface by supersonic flame spraying technology, atmospheric plasma spraying technology or laser cladding technology.

8. A multifunctional coating for hot rolling roll of profiles prepared by the preparation method according to claim 7, characterized in that: The coating thickness is 50-1000 μm.

9. A multifunctional coating for hot rolling roll of profiles prepared by the preparation method according to claim 7, characterized in that: The coating thickness is 50-150 μm.

10. Use of the multifunctional coating for hot rolling rollers of profiles as claimed in any one of claims 8 or 9 in a hot rolling production line for profiled steel.

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