A process for making a straightening alloy roll for a steel mill

Abstract

The application discloses a manufacturing process of a straightening alloy roller for a steel plant, and belongs to the technical field of straightening rollers for rolling steel, and comprises the following steps: S1, blank roller preparation: a straightening roller sleeve composition is designed according to specific working conditions, and a blank roller is prepared, and then the blank roller is placed horizontally and is coarsely ground; S2, quenching and tempering heat treatment: the blank roller after the coarse grinding is subjected to quenching and tempering treatment, and the bending deformation amount of the blank roller is controlled to be within 2 mm; S3, quenching: the blank roller after the quenching and tempering is placed horizontally, and is quenched by using a medium-frequency induction in a double-frequency quenching inductor, and the quenching temperature is 1010-1040 DEG C; S4, tempering: the blank roller after the quenching is subjected to low-temperature tempering, and the tempering temperature is 120-145 DEG C; and S5, machining: the blank roller after the tempering is subjected to grinding machining, including coarse grinding, semi-fine grinding and fine grinding. The application has excellent wear resistance and reliability in actual application and production, the working surface keeps good cleanness, and the appearance quality of the steel product is effectively improved.

Description

Technical Field

[0001] This invention belongs to the technical field of straightening rolls for steel rolling, and specifically relates to a manufacturing process for a straightening alloy roll for steel plants. Background Technology

[0002] Straightening is the final production process for hot-rolled commercial steel sections. The working temperature of hot-rolled straightening rolls is generally in the range of 500 to 700℃. It is necessary not only to ensure the dimensional accuracy and shape requirements of the steel sections, but also to ensure the surface quality of the steel sections, and to prevent surface defects such as roll marks and scratches. It is also necessary to improve the straightening machine's operating rate, reduce frequent roll changes, and avoid uneven wear and damage to the roll surface. Therefore, straightening rolls must have excellent wear resistance, scratch resistance, and deformation resistance to ensure their service life and performance.

[0003] The surface of straightening rolls is typically machined into specific perforations. During steel straightening, the perforated surface directly contacts the steel section, and under the influence of temperature and pressure, it primarily withstands bending fatigue and severe wear. Therefore, straightening rolls are required to have high surface hardness, sufficient rigidity, and high fatigue strength (including contact fatigue), and to prevent cracking and oxidation under repeated thermal stress. In my country, most steel section straightening rolls are made of alloy tool steel and chilled alloy cast iron with a high nickel-chromium-molybdenum content. Alloy tool steel straightening rolls are mostly produced using forging methods, resulting in high toughness but relatively insufficient wear resistance, increasing the frequency of replacement. Furthermore, alloy tool steel straightening rolls are expensive, difficult to process, and detrimental to production. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention. This invention discloses a manufacturing process for a straightening alloy roller used in steel plants, comprising the following steps:

[0005] S1. Preparation of blank roll: The composition of the straightening roll sleeve is designed and the blank roll is prepared according to the specific working conditions. Then, the blank roll is placed horizontally and rough ground.

[0006] S2. Quenching and tempering heat treatment: Quenching and tempering treatment is performed on the blank roll after rough grinding to control the bending deformation of the blank roll within 2mm.

[0007] S3. Quenching: The tempered billet roll is placed horizontally and quenched using the medium frequency induction in the dual-frequency quenching inductor. The quenching temperature is 1010℃~1040℃.

[0008] S4. Tempering: The quenched billet roll is tempered at a low temperature of 120℃~145℃.

[0009] S5. Machining: Grinding the tempered blank rolls, including rough grinding, semi-fine grinding and fine grinding.

[0010] In order to avoid bending deformation of the straightening roller in this application, a support is added at the lower end of the blank roller in the middle position during the rough grinding, quenching and grinding processes described in S1, S3 and S5.

[0011] In this application, in order to prevent the strength of the straightening roll from decreasing after heating, the support described in S3 is continuously moved as the quenching process proceeds, so that the support is located in the middle of the unquenched part of the blank roll until half of the blank roll is quenched, and then the support is moved to the middle of the quenched part for support. As the quenching process continues, the support is moved again so that it is located in the middle of the quenched part of the blank roll until the quenching is completed.

[0012] In order to ensure the stability of the straightening roller structure, reduce residual stress and prevent deformation, S3 also includes 2 to 4 heat setting treatments after quenching.

[0013] In this application, to ensure that the straightening roller sleeve has sufficient hardness and good wear and crack resistance, the straightening roller sleeve composition design described in S1 includes the following components and their weight percentages: C: 0.36-0.45%, Cr: 12.00-14.00%, Ni: 2.00-2.50%, Mo: 2.00-3.00%, W: 2.00-3.00%, Ti: 0.85-1.25%, Si≤1.50%, Mn≤2.00%, P≤0.035%, S≤0.03%, and the remainder is Fe.

[0014] In order to ensure the structural stability of the straightening roller in this application, a wear-resistant alloy layer is provided on the outer side of the straightening roller sleeve, and a double helical groove is provided between the wear-resistant alloy layer and the straightening roller sleeve for connecting the two.

[0015] In this application, to ensure the structural stability of the straightening roller, the connection of the double helical groove is a circular arc transition.

[0016] In order to ensure the structural stability of the straightening roller in this application, a fastening structure is provided on the side of the double helical groove. The fastening structure includes one or more structures with a semi-circular cross-section, a U-shaped cross-section, or a V-shaped cross-section.

[0017] In this application, to ensure that the straightening roller sleeve has good wear resistance and crack resistance, the composition of the wear-resistant alloy layer by weight percentage is as follows: C: 0.50-0.80%, Cr: 4.00-8.00%, Mo: 1.00-4.00%, W: 4.00-7.00%, Si: 0.10-0.60%, Mn: 2.00-4.00%, V: 0.20-0.50%, with the remainder being Fe.

[0018] In this application, to prevent grinding thermal deformation, the feed rate of the semi-finish grinding in S5 is 0.01mm to 0.1mm, and the feed rate of the finish grinding is 0.005mm to 0.02mm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention discloses a steel mill straightening alloy roll. By adding Cr and C to the components of the straightening roll sleeve and the external wear-resistant alloy layer, the performance of the straightening roll is further improved. Specifically, Cr in the straightening roll sleeve can strengthen the Ni matrix through solid solution and enhance its passivation ability, effectively improving corrosion resistance and high-temperature oxidation resistance. Simultaneously, Cr can form a hard intermetallic compound phase with Si, which provides dispersion strengthening to the straightening roll sleeve and the wear-resistant alloy layer, thereby improving the wear resistance of the structure itself. This results in the straightening roll possessing properties such as heat resistance, corrosion resistance, oxidation resistance, wear resistance, and high-temperature erosion resistance. In practical production applications, it exhibits excellent wear resistance and reliability, maintaining a good surface finish, effectively improving the appearance quality of steel products, and possesses significant application and promotion value. Attached Figure Description

[0021] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 for Figure 1 Enlarged view of point A in the middle. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] The application principle of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] like Figure 1-2 As shown, the manufacturing process of a steel mill straightening alloy roller includes the following specific steps:

[0028] S1. Preparation of the blank roll: The composition of the straightening roll sleeve 10 is designed and the blank roll is fabricated according to the specific working conditions. The blank roll is then placed horizontally and subjected to rough grinding. During rough grinding, a support is added at the lower end of the blank roll in the middle position for support and protection, preventing bending deformation of the straightening roll. The composition of the straightening roll sleeve 10, by weight percentage, includes: 0.36% C, 14.00% Cr, 2.10% Ni, 2.20% Mo, 2.40% W, 0.85% Ti, 1.50% Si, 2.00% Mn, 0.035% P, and 0.03% S. The balance is Fe; the composition of the wear-resistant alloy layer 20 by weight percentage includes: 0.50% C, 4.00% Cr, 1.00% Mo, 4.00% W, 0.20% Si, 2.00% Mn, 0.20% V, and the balance is Fe.

[0029] S2. Quenching and tempering heat treatment: Quenching and tempering the blank roll after rough grinding so that the bending deformation of the blank roll is less than 2mm, thereby obtaining a quenched and tempered blank roll.

[0030] S3. Quenching: The tempered billet roll is placed horizontally and quenched using the medium frequency induction of a dual-frequency quenching inductor at a quenching temperature of 1010℃. During the quenching process, the support of the lower end of the billet roll is continuously moved to ensure that the support is always located in the middle of the unquenched part of the billet roll until half of the billet roll is quenched. Then the support is moved to the middle of the quenched part for support. As the quenching progresses, the support is moved again to ensure that the support is in the middle of the quenched part of the billet roll until the quenching is completed. After quenching, 2 to 4 heat setting treatments are performed.

[0031] S4. Tempering: The quenched billet roll is tempered at a low temperature of 120℃.

[0032] S5. Machining: Grinding is performed on the tempered billet roll, including rough grinding, semi-finish grinding, and finish grinding. The feed rate for semi-finish grinding is 0.05mm, and the feed rate for finish grinding is 0.01mm. During the grinding process, the support of the lower end of the billet roll is continuously moved as the grinding process progresses, ensuring that the support is always located in the middle of the unground part of the billet roll, until half of the billet roll is ground. Then, the support is moved to the middle of the ground part for support, and it is moved again as the grinding progresses, so that the support is always located in the middle of the ground part of the billet roll, until the grinding process is completed.

[0033] The outer side of the straightening roller sleeve 10 is provided with a wear-resistant alloy layer 20, and a double spiral groove 30 is provided between the wear-resistant alloy layer 20 and the straightening roller sleeve 10 for connecting the two; wherein, the cross-section of the straightening roller sleeve 10 and the wear-resistant alloy layer 20 is a structure with large ends and small middle, and the thickness of the middle part of the wear-resistant alloy layer 20 is greater than the thickness of the two ends. During the straightening process, to ensure stable straightening, the outer wall of the roller sleeve is generally designed with an arc shape. However, this design often leads to a concentrated working area, specifically the middle of the arc shape. To address this, the thickness of the wear-resistant alloy layer 20 is increased in this area to ensure a longer service life compared to traditional techniques. The double helical groove 30 features a V-shaped cross-section with a depth of 0.5mm. This design ensures a strong bond between the wear-resistant alloy layer 20 and the root of the double helical groove 30, while also maintaining their bonding strength. Furthermore, the connection point of the double helical groove 30 is a rounded transition. During high-speed operation, this double-helix design with opposite rotation directions transfers the compressive stress to both sides, ensuring that at least one side maintains its efficient pressure-bearing capacity, thus guaranteeing a long service life. Simultaneously, a fastening structure 31 is provided on the side of the double helical groove 30. This fastening structure 31 includes one or more cross-sections such as a semi-circular, U-shaped, or V-shaped structure, preferably a semi-circular structure. The groove wall is provided with a fastening structure 31, which increases the bearing capacity of the roller sleeve body 10 and the wear-resistant alloy layer 20 after the wear-resistant alloy layer 20 is compressed during the rolling process, disperses the extrusion stress to both sides, and further enhances the bonding strength between the two.

[0034] Example 2

[0035] The straightening roller sleeve 10 comprises, by weight percentage: 0.40% C, 13.00% Cr, 2.25% Ni, 3.00% Mo, 2.80% W, 1.05% Ti, 1.50% Si, 2.00% Mn, 0.035% P, 0.03% S, with the balance being Fe; the wear-resistant alloy layer 20 comprises, by weight percentage: 0.65% C, 6.00% Cr, 2.50% Mo, 6.00% W, 0.40% Si, 3.00% Mn, 0.35% V, with the balance being Fe; the quenching temperature is 1010℃, the tempering temperature is 130℃; the infeed for semi-finish grinding is 0.08mm, and the infeed for finish grinding is 0.01mm.

[0036] Example 3

[0037] The straightening roller sleeve 10 comprises, by weight percentage: 0.45% C, 12.00% Cr, 2.50% Ni, 2.50% Mo, 3.00% W, 1.25% Ti, 1.00% Si, 1.50% Mn, 0.03% P, 0.02% S, with the balance being Fe; the wear-resistant alloy layer 20 comprises, by weight percentage: 0.80% C, 8.00% Cr, 4.00% Mo, 7.00% W, 0.60% Si, 4.00% Mn, 0.50% V, with the balance being Fe; the quenching temperature is 1040℃, the tempering temperature is 145℃; the infeed for semi-finish grinding is 0.1mm, and the infeed for finish grinding is 0.02mm.

[0038] Table 1: Component proportions and hot pressing process conditions for straightening roller sleeves:

[0039]

[0040] Table 2: Composition ratio of wear-resistant alloy layer:

[0041]

[0042]

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for making a straightened alloy roll for a steel mill, characterized by, It comprises the following steps: S1, blank roll preparation: according to the specific working conditions, the composition of the straightening roll sleeve is designed and the blank roll is prepared, and then the blank roll is placed horizontally and is coarsely ground; S2, quenching and tempering: the coarsely ground blank roll is quenched and tempered, and the bending deformation of the blank roll is controlled within 2mm; S3, quenching: the quenched and tempered blank roll is placed horizontally, and the middle frequency induction of the double-frequency quenching inductor is used for quenching, and the quenching temperature is 1010-1040℃; S4, tempering: the quenched blank roll is tempered at a low temperature, and the tempering temperature is 120-145℃; S5, machining: the quenched and tempered blank roll is ground, including coarse grinding, semi-fine grinding and fine grinding; In the coarse grinding and grinding process in S1 and S5, a support is additionally arranged at the lower end of the middle position of the blank roll; In S3, the support is moved constantly during the quenching process, so that the support is located at the middle position of the unquenched part of the blank roll, until the blank roll is quenched to half, then the support is moved to the middle position of the quenched part for support, and then moved again during the quenching process, so that the support is located at the middle position of the quenched part of the blank roll until the quenching is completed; S3 further comprises 2-4 times of heat setting treatment after quenching; The composition design of the straightening roll sleeve in S1 comprises the following components and the weight percentage of each component: C: 0.36-0.45%, Cr: 12.00-14.00%, Ni: 2.00-2.50%, Mo: 2.00-3.00%, W: 2.00-3.00%, Ti: 0.85-1.25%, Si≤1.50%, Mn≤2.00%, P≤0.035%, S≤0.03%, and the rest is Fe; The outer side of the straightening roll sleeve is provided with a wear-resistant alloy layer, and a double helical groove is arranged between the wear-resistant alloy layer and the straightening roll sleeve for connecting the two; The middle thickness dimension of the wear-resistant alloy layer is greater than the thickness dimension of both ends The connection of the double helical groove is a circular arc transition; The side of the double helical groove is provided with a fastening structure, which comprises one or more of a half-circle structure, a U-shaped structure or a V-shaped structure in cross section; The composition of the wear-resistant alloy layer comprises the following components in terms of weight percentage: C: 0.50-0.80%, Cr: 4.00-8.00%, Mo: 1.00-4.00%, W: 4.00-7.00%, Si: 0.10-0.60%, Mn: 2.00-4.00%, V: 0.20-0.50%, and the rest is Fe; The feed rate of the semi-fine grinding in S5 is 0.01-0.1mm, and the feed rate of the fine grinding is 0.005-0.02mm.

Images