A cross-rolling assembly and method suitable for large size high temperature alloy bar

Abstract

This invention discloses a skew rolling assembly suitable for large-size high-temperature alloy bars, comprising four rolls of identical shape and size, all of which are active rolls. During production, all four rolls promote the forward flow of the billet metal along the rolling direction, avoiding the jamming phenomenon caused by the guide plate obstructing the forward flow of the billet in the existing rolling process. Furthermore, the four rolls increase the rolling speed and the degree of deformation. This invention also provides a skew rolling method suitable for large-size high-temperature alloy bars. Utilizing the aforementioned skew rolling assembly, the four rotating active rolls are used for skew rolling of the bars, increasing the rolling speed and avoiding the jamming problem that easily occurs in existing two-roll and guide plate rolling processes. This ensures forming quality, improves rolling production efficiency, and increases the degree of deformation.

Description

Technical Field

[0001] This invention relates to the field of bar skew rolling technology, and in particular to a skew rolling assembly and method suitable for large-size high-temperature alloy bars. Background Technology

[0002] Large-size high-temperature alloy ultrafine-grained rods have great potential in industrial applications, but the preparation processes of ultrafine-grained high-temperature alloys mentioned in existing patents or papers have two problems: (1) At present, the preparation of ultrafine-grained materials using intense plastic deformation technology is developing rapidly, but the five mainstream methods are high-pressure torsion (HPT), equal channel angle extrusion (ECAP), cumulative roll forming (ARB), multi-directional forging (MF), and torsion extrusion (TE). The following problems exist: high-pressure torsion (HPT) and equal channel angle extrusion (ECAP) have large forming loads, and existing forming equipment generally does not have the loading capacity for industrial large-size products, so the finished product size is small; cumulative roll forming (ARB) has poor deformation penetration and can only prepare thin plates; multi-directional forging (MF) has poor deformation uniformity and the effective deformation zone volume is small; torsion extrusion (TE) has a deformation zone at the millimeter level and cannot prepare large-size bulk ultrafine-grained materials. (2) When using a two-roll + two-guide-plate skew rolling method, the two rolls are active deformation tools, causing the billet to spiral forward and promoting the metal to flow forward along the rolling direction; the two guide plates are stationary, which can improve the dimensional accuracy of the rolled bar, but the friction between them and the billet hinders the forward flow of the metal along the rolling direction. For example, the prior art with publication numbers CN109772890A and CN108277446B discloses an ultrafine grain rolling method for large-size high-temperature alloy bars, which also uses rolling tools of rolls and guide plates.

[0003] During large-scale deformation, as the cross-sectional area of ​​the deformation zone decreases, redundant metal is generated. This metal extends towards the guide plate, contacts the guide plate, and generates frictional resistance. It gradually fills the gap between the billet and the guide plate and then flows into the gap between the guide plate and the rolls. At the same time, the metal in contact with the guide plate dissipates heat quickly, and its fluidity deteriorates as the temperature decreases. Ultimately, this leads to the phenomenon that the billet only rotates and does not move forward or neither rotates nor moves forward during the rolling process, causing jamming, reduced production efficiency, and increased die wear.

[0004] Therefore, how to change the current situation where the rolling method for large-size high-temperature alloy bars is prone to jamming, resulting in low rolling efficiency, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a skew rolling assembly and method suitable for large-size high-temperature alloy bars, so as to solve the problems existing in the prior art, minimize the rolling jamming phenomenon, increase the degree of deformation, and improve the rolling production efficiency of large-size high-temperature alloy bars.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a skew rolling assembly suitable for large-size high-temperature alloy bars, comprising:

[0007] Four actively rotating rollers, wherein the rollers are rotating bodies with unequal diameters;

[0008] The rolling line is the straight line in which the billet moves during rolling, and the four rolls are evenly distributed around the rolling line.

[0009] Preferably, the four rollers are of the same size.

[0010] Preferably, the larger diameter ends of the four rolls are evenly distributed around the rolling line and form the feed end of the billet.

[0011] Preferably, the roll includes a first frustum, a second frustum, a third frustum, and a fourth frustum arranged coaxially and connected in sequence. The axial length ratio of the first frustum, the second frustum, the third frustum, and the fourth frustum is 3:1:1:1. The roll surface cone angle of the first frustum is 3° to 4.5°, the roll surface cone angle of the second frustum is 3° to 4°, the roll surface cone angle of the third frustum is 2° to 3.5°, the roll surface cone angle of the fourth frustum is 1° to 3.5°, and the rolling angle of the roll is 5° to 7°.

[0012] Preferably, the ratio of the throat diameter of the roll to the diameter of the billet is 1.0 to 5.0, and the ratio of the axial length of the roll to the throat diameter is 3.0 to 7.0.

[0013] Preferably, the area enclosed by the four rollers is a deformation zone, and the spacing between the relative rollers can be adjusted;

[0014] In a plane perpendicular to the rolling line, the ratio of the spacing between two pairs of spaced-apart rolls is the ellipticity. The ellipticity is equal in any plane perpendicular to the rolling line within the deformation zone, and the ellipticity is 1.0 to 1.1.

[0015] Within the deformation zone, the feed angle is 7° to 9°, the rolling angle is 5° to 7°, the rotational speed of the rolls is 10 r / min to 11 r / min, and the diameter reduction rate is 60% to 70%.

[0016] The present invention also provides a method for skew rolling of large-size high-temperature alloy bars. Using the above-mentioned skew rolling assembly for large-size high-temperature alloy bars, the four rolls rotate around their respective axes. After the billet is heated, it enters the deformation zone enclosed by the four rolls for variable cross-section rolling, completing one pass of forward rolling.

[0017] Preferably, after completing one pass of forward rolling, the rotation direction of the four rolls and the spacing between the rolls are adjusted, and a second pass of rolling is performed in the reverse direction. The forward rolling and reverse rolling are repeated until the rolling is completed, and the billet is cooled.

[0018] The billet is heated to a temperature of 915℃~1115℃ for a time of T (in minutes), where T=D. b ×(0.6-0.8), where D b The diameter of the blank is in mm.

[0019] The present invention achieves the following technical effects compared to the prior art:

[0020] The skew rolling assembly of the present invention, applicable to large-size high-temperature alloy bars, employs four identical rolls, all of which are active rolls. During production, all four rolls promote the forward flow of the billet metal along the rolling direction, avoiding the jamming phenomenon caused by the guide plate obstructing the forward flow of the billet in the prior art rolling process. Furthermore, the use of four rolls increases the rolling speed. In addition, by adjusting the rotation direction and roll spacing of the four rolls, reciprocating multi-pass rolling can be achieved, increasing the degree of deformation and further improving the rolling production efficiency of large-size high-temperature alloy bars.

[0021] This invention also provides a method for skew rolling of large-size high-temperature alloy bars. Utilizing the aforementioned skew rolling assembly for large-size high-temperature alloy bars, four rolls rotate around their respective axes. After heating, the billet enters the area enclosed by the four rolls, achieving a single forward rolling pass. During this process, the larger diameter end of the four rolls can form the feed end. Using this skew rolling method for large-size high-temperature alloy bars, the forming load is lower than that of traditional methods involving severe plastic deformation because the billet only partially contacts the rolls. The use of four rotating active rolls for skew rolling increases the rolling speed, avoids the jamming problem common in existing two-roll and guide plate rolling methods, increases the degree of deformation, ensures forming quality, and improves rolling production efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the skew rolling assembly for large-size high-temperature alloy bars according to the present invention;

[0024] Figure 2 This is a schematic diagram of the skew rolling assembly of the present invention for large-size high-temperature alloy bars at other angles;

[0025] Figure 3 This is a schematic diagram of the roll structure of the skew rolling assembly for large-size high-temperature alloy bars according to the present invention.

[0026] Figure 4 This is a metallographic image of the billet before rolling in an embodiment of the skew rolling method for large-size high-temperature alloy bars of the present invention;

[0027] Figure 5 This is a metallographic image of a billet after one pass of rolling, as shown in an embodiment of the skew rolling method for large-size high-temperature alloy bars of the present invention.

[0028] Wherein, 1 is the rolling roll, 2 is the first frustum, 3 is the second frustum, 4 is the third frustum, 5 is the fourth frustum, and 6 is the billet;

[0029] α is the rolling angle, γ1 is the roll surface cone angle of the first frustum, γ2 is the roll surface cone angle of the second frustum, γ3 is the roll surface cone angle of the third frustum, γ4 is the roll surface cone angle of the fourth frustum, L1 is the axial length of the first frustum, L2 is the axial length of the second frustum, L3 is the axial length of the third frustum, L4 is the axial length of the fourth frustum, and R1 is the roll throat radius. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The purpose of this invention is to provide a skew rolling assembly and method suitable for large-size high-temperature alloy bars, so as to solve the problems existing in the prior art, minimize the rolling jamming phenomenon, increase the deformation amount, and improve the rolling production efficiency of large-size high-temperature alloy bars.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Please refer to Figures 1-5 ,in, Figure 1 This is a schematic diagram of the skew rolling assembly for large-size high-temperature alloy bars according to the present invention. Figure 2 This is a schematic diagram of the skew rolling assembly of the present invention, applicable to large-size high-temperature alloy bars, at other angles. Figure 3This is a schematic diagram of the roll structure of the skew rolling assembly for large-size high-temperature alloy bars according to the present invention. Figure 4 This is a metallographic image of the billet before rolling in an embodiment of the skew rolling method for large-size high-temperature alloy bars of the present invention. Figure 5 This is a metallographic image of a billet after one pass of rolling, as shown in an embodiment of the skew rolling method for large-size high-temperature alloy bars of the present invention.

[0034] This invention provides a skew rolling assembly suitable for large-size high-temperature alloy bars, comprising four actively rotating rolls 1, each roll being a rotating body with unequal diameters. The rolling line is defined as the straight line along which the billet 6 moves during rolling, and the four rolls 1 are evenly distributed circumferentially around the rolling line.

[0035] The skew rolling assembly of the present invention, applicable to large-size high-temperature alloy bars, employs four identical rolls 1, all of which are active rolls 1. During production, the four rolls 1 promote the forward flow of the billet 6 metal along the rolling direction, avoiding the jamming phenomenon caused by the guide plate obstructing the forward flow of the billet 6 in the prior art rolling process. Furthermore, the use of four rolls 1 increases the rolling speed. In addition, by adjusting the rotation direction of the four rolls 1 and the spacing between the rolls 1, reciprocating multi-pass rolling can be achieved, increasing the degree of deformation and further improving the rolling production efficiency of large-size high-temperature alloy bars.

[0036] The four rollers 1 have the same structure and dimensions.

[0037] In this specific embodiment, the larger diameter ends of the four rolls 1 are evenly distributed around the rolling line to form the feed end of the billet 6, such as... Figure 1 and Figure 2 As shown.

[0038] Specifically, the throat diameter D1 of roll 1 (D1 = 2R1, where R1 is the roll throat radius) With billet diameter D 6 b satisfy D1 / D b = 1.0～5.0 The length L of the roll body of roll 1 and the throat diameter D1 of roll 1 satisfy L / D1 = 3.0~7.0. Roll 1 includes a first frustum 2, a second frustum 3, a third frustum 4, and a fourth frustum 5, which are coaxially arranged and sequentially connected. The axial length ratio of the first frustum 2, the second frustum 3, the third frustum 4, and the fourth frustum 5 is L1:L2:L3:L4 = 3:1:1:1. The roll surface cone angles γ1, γ2, γ3, γ4, and γ5 are 3°~4.5°, 3°~4°, 2°~3.5°, and 1°~3.5°, respectively. The rolling angle α of roll 1 is 5°~7°. In actual production, the dimensions of the four rolls 1 can be adjusted according to the specifications of the billet 6 and production requirements to improve the flexibility and adaptability of the skew rolling assembly.

[0039] It should also be emphasized that the spacing between the four rolls 1 can be adjusted to adjust the specifications of the deformation zone according to the requirements of bar rolling, further improving the adaptability of the skew rolling assembly.

[0040] More specifically, in a plane perpendicular to the rolling line, the ratio of the spacing between two oppositely placed rolls 1 is the ellipticity. The ellipticity in any plane perpendicular to the rolling line within the deformation zone is equal, and the ellipticity is 1.0 to 1.1. Adjusting the ellipticity can adjust the specifications of the deformation zone to meet different rolling requirements.

[0041] In addition, within the deformation zone, the feed angle is 7° to 9°, the rolling angle is 5° to 7°, the rotational speed of roll 1 is 10 r / min to 11 r / min, and the diameter reduction rate is 60% to 70%. In practical applications, the working parameters of roll 1 can be adjusted according to the rolling production requirements.

[0042] Furthermore, the present invention also provides a method for skew rolling of large-size high-temperature alloy bars. Using the above-mentioned skew rolling assembly for large-size high-temperature alloy bars, four rolls 1 rotate around their respective axes. After the billet 6 is heated, it enters the area enclosed by the four rolls 1 to achieve one pass of forward rolling.

[0043] It should be noted that after completing one pass of forward rolling, the rotation direction and spacing of the four rolls 1 can be adjusted to perform a second pass of rolling, further improving rolling production efficiency. Forward and reverse rolling are repeated until the rolling process is complete. The billet 6 is then cooled, either by air cooling or water cooling to room temperature. In this specific embodiment, the billet 6 is selected from high-temperature alloy GH4169 billets with a diameter of 300mm–500mm and a length of 300mm–15000mm.

[0044] It should also be noted that billet 6 can be heated using a heating furnace. The heating temperature of billet 6 is 915℃~1115℃, and the heating time is T, in minutes, where T=D. b ×(0.6-0.8), where D b The diameter of blank 6 is in mm.

[0045] This invention relates to a skew rolling assembly and method for large-size high-temperature alloy bars. Four co-rotating rolls 1 are evenly distributed circumferentially around the rolling centerline at 90° intervals. All four rolls 1 are powered rolls, each propelling the billet 6 forward along the rolling direction. This solves the rolling jamming problem caused by the obstruction of the guide plate and increases the rolling speed. During rolling, the billet 6 only partially contacts the rolls 1, resulting in a lower forming load compared to mainstream techniques involving intense plastic deformation. The spacing and rotation direction of the rolls 1 are adjustable. After the first pass, the spacing and rotation direction of the rolls 1 can be quickly adjusted, allowing the billet 6 to immediately undergo a second pass in the opposite direction to the first pass. This process can be repeated for multiple passes, saving rolling time and further improving rolling production efficiency. This invention utilizes four-roll skew rolling, saving production costs and improving production efficiency while ensuring the smooth completion of the rolling process.

[0046] Definitions:

[0047] Rolling jam: refers to the phenomenon during the rolling process where the billet only rotates without moving forward, or neither rotates nor moves forward.

[0048] Ellipticity: In this paper, ellipticity refers to the ratio of the distances between two oppositely placed rolls 1 in a plane perpendicular to the rolling line. The ellipticity requirement is ≥1. (Specifically, the ellipticity is the value obtained by comparing the distance between two oppositely placed rolls 1 with a larger distance with the distance between two other oppositely placed rolls 1 with a smaller distance).

[0049] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A skew-rolled assembly suitable for large-size high-temperature alloy bars, characterized in that, include: Four actively rotating rollers, wherein the rollers are rotating bodies with unequal diameters; The rolling line is the straight line in which the billet moves during rolling, and the four rolls are evenly distributed around the rolling line in the circumference. The four rollers are of the same size; The rolling mill includes a first frustum, a second frustum, a third frustum, and a fourth frustum arranged coaxially and connected in sequence. The axial length ratio of the first frustum, the second frustum, the third frustum, and the fourth frustum is 3:1:1:

1. The roll surface cone angle of the first frustum is 3°~4.5°, the roll surface cone angle of the second frustum is 3°~4°, the roll surface cone angle of the third frustum is 2°~3.5°, the roll surface cone angle of the fourth frustum is 1°~3.5°, and the rolling angle of the rolling mill is 5°~7°. After completing one pass of forward rolling, the rotation direction of the four rolls and the spacing between the rolls are adjusted, and a second pass of rolling is performed in the reverse direction. The forward rolling and reverse rolling are repeated until the rolling is completed.

2. A cross-rolling assembly suitable for use with large size high temperature alloy bars as claimed in claim 1, wherein: The larger diameter ends of the four rollers are evenly distributed around the rolling line and form the feed end of the billet.

3. The skew rolling assembly for large-size high-temperature alloy bars according to claim 1, characterized in that: The ratio of the throat diameter of the roll to the diameter of the billet is 1.0 to 5.0, and the ratio of the axial length of the roll to the throat diameter is 3.0 to 7.

0.

4. The skew rolling assembly for large-size high-temperature alloy bars according to claim 1, characterized in that: The area enclosed by the four rollers is the deformation zone, and the spacing between the rollers can be adjusted. In a plane perpendicular to the rolling line, the ratio of the spacing between two pairs of spaced-apart rolls is the ellipticity. The ellipticity is equal in any plane perpendicular to the rolling line within the deformation zone, and the ellipticity is 1.0~1.

1. Within the deformation zone, the feed angle is 7°~9°, the rolling angle is 5°~7°, the rotational speed of the rolls is 10r / min~11r / min, and the diameter reduction rate is 60%-70%.

5. A method for skew rolling of large-size high-temperature alloy bars, utilizing the skew rolling assembly for large-size high-temperature alloy bars as described in any one of claims 1-4, characterized in that: All four rollers rotate around their respective axes. After the billet is heated, it enters the deformation zone enclosed by the four rollers for variable cross-section rolling, completing one pass of forward rolling.

6. A method of cross-rolling a large size superalloy bar according to claim 5, wherein: After completing one pass of forward rolling, the rotation direction of the four rolls and the spacing between the rolls are adjusted, and a second pass of rolling is performed in the reverse direction. The forward rolling and reverse rolling are repeated until the rolling is completed, and the billet is cooled. The blank heating temperature is 915-1115℃, the heating time is T, unit is min, T=D b ×(0.6-0.8), wherein D b is the diameter of the blank, unit is mm.

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