CN219188120U - Hot rolling forming tool capable of improving forming precision of corners of thick-wall hexagonal steel pipes - Google Patents

Abstract

The utility model discloses a hot-rolling forming tool capable of improving the forming precision of corners of thick-wall hexagonal steel pipes, which solves the problem of improving the forming quality of corners when hot-rolling forming square pipes by taking hot-rolling seamless steel pipes as blanks; taking a hot-rolled seamless steel pipe as a blank of a hot-rolled square pipe or rectangular pipe, preheating the hot-rolled seamless steel pipe blank to 800-1000 ℃, and then carrying out continuous gradual roll bending forming under the common rolling of an outer roll set and an inner roll set of a roll bending forming device; the roll bending forming device comprises a blank feeding device, a roll bending frame, a core rod device, a core rod supporting device and a roll holding device; the devices are matched cooperatively, and the hot-rolled seamless steel tube blank is rolled into a square steel tube or a rectangular steel tube; the seamless round tube is continuously and gradually bent and formed under the combined action of the outer roller group and the inner roller group, and the forming precision of the corners of the hexagonal steel tube is improved.

Description

Hot rolling forming tool capable of improving forming precision of corners of thick-wall hexagonal steel pipes

Technical Field

The utility model relates to the technical field of hot-rolled seamless steel pipes, in particular to a hot-rolled forming tool for a thick-wall hexagonal steel pipe, which can improve corner forming quality.

Background

Hexagonal steel pipes are used in the construction field of steel structures, machine manufacturing, building frame construction, and the like; at present, the forming process of the hexagonal steel pipe comprises a hot rolling forming process, a cold drawing forming process and an extrusion forming welding square pipe process; the cold drawing forming process has the defects of multiple working procedures, small pass deformation quantity, long production period and low forming efficiency; the welding hexagonal tube process uses hot rolled strip steel as raw material, and adopts multi-pass extrusion and welding forming, the whole process is not subjected to heat treatment, and the stress generated in the extrusion forming process can not be removed.

The hot-rolled seamless hexagonal pipe is suitable for mass production, the production efficiency is high, the hot-rolled hexagonal pipe can destroy the casting structure of steel ingots, refine the crystal grains of the steel, and eliminate the defect of microstructure, so that the steel structure is more compact, and the mechanical property is greatly improved; however, in the hot rolling process, the difficult problems of low forming precision and more defects of the hexagonal steel pipe, particularly the corner forming, are easy to occur, and the defects include: the problems of asymmetry and fullness of corner forming, forming limit and internal angle cracking; if a hot-rolled seamless steel tube is used as a blank, the forming efficiency of the hot-rolled seamless hexagonal steel tube can be greatly improved, but how to improve the integral forming precision of the hexagonal steel tube during hot-rolling forming, in particular to improve the corner forming quality of the hexagonal steel tube, becomes a problem to be solved on site.

Disclosure of Invention

The utility model provides a hot rolling forming tool for a thick-wall hexagonal steel pipe, which can improve the corner forming quality, and solves the technical problem of how to improve the corner forming quality when a hot rolling seamless steel pipe is used as a blank for hot rolling the hexagonal steel pipe.

The utility model solves the technical problems by the following technical proposal:

the general conception of the utility model is that: taking a hot-rolled seamless steel pipe as a blank of a hot-rolled hexagonal pipe, preheating the hot-rolled seamless steel pipe blank to 800-1000 ℃, and then carrying out continuous gradual roll bending forming under the common rolling of an outer roll set and an inner roll set of a roll bending forming device; the roll bending forming device comprises a blank feeding device, a roll bending frame, a core rod device, a core rod supporting device and a roll holding device; and all the devices are matched cooperatively to roll the hot-rolled seamless steel tube blank into a hexagonal steel tube.

A hot rolling forming tool for a thick-wall hexagonal steel pipe capable of improving corner forming quality comprises a seamless round pipe blank feeding mechanism, a blank conveying roller way, a seamless round pipe blank, a biting roll bending machine frame, a first roll bending machine frame, a second roll bending machine frame, a third roll bending machine frame, a fourth roll bending machine frame, a fifth roll bending machine frame, a sixth roll bending machine frame, a core rod supporting device, a first core rod holding roll device and a core rod; a seamless round tube blank feeding mechanism is arranged at the left end of the blank conveying roller way, a first core rod holding roller device is arranged at the right end of the blank conveying roller way, a biting roller bending machine frame, a first roller bending machine frame, a second roller bending machine frame, a third roller bending machine frame, a fourth roller bending machine frame, a fifth roller bending machine frame and a sixth roller bending machine frame are sequentially arranged at intervals from left to right, a biting outer roller group is arranged in the biting roller bending machine frame, and three outer rollers in the biting outer roller group are arranged in a regular triangle; the left end of the core rod sequentially passes through the sixth roll bending frame, the fifth roll bending frame, the fourth roll bending frame, the third roll bending frame, the second roll bending frame, the first roll bending frame and the biting roll bending frame from right to left, and is arranged at the left side of the biting roll bending frame, and the right end of the core rod is arranged in the core rod holding device; a first outer roller set is arranged in the first roller bending frame, three outer rollers in the first outer roller set are arranged in a regular triangle, a second outer roller set is arranged in the second roller bending frame, the three outer rollers in the second outer roller set are also arranged in a regular triangle, and a regular hexagonal rolling port is formed in space along the left-right direction between the three outer rollers in the first outer roller set and the three outer rollers in the second outer roller set; a third outer roller set is arranged in the third roller bending frame, three outer rollers in the third outer roller set are arranged in a regular triangle, a fourth outer roller set is arranged in the fourth roller bending frame, the three outer rollers in the fourth outer roller set are also arranged in a regular triangle, and a regular hexagonal rolling port is formed in space along the left-right direction between the three outer rollers in the third outer roller set and the three outer rollers in the fourth outer roller set; a fifth outer roll set is arranged in the fifth roll bending frame, three outer rolls in the fifth outer roll set are arranged in a regular triangle, a sixth outer roll set is arranged in the sixth roll bending frame, the three outer rolls in the fifth outer roll set are also arranged in a regular triangle, and a regular hexagonal rolling port is formed in space along the left-right direction between the three outer rolls in the fifth outer roll set and the three outer rolls in the sixth outer roll set; a first group of inner angle forming rollers, a second group of inner angle forming rollers, a third group of inner angle forming rollers, a fourth group of inner angle forming rollers, a fifth group of inner angle forming rollers and a sixth group of inner angle forming rollers are sequentially arranged on the core rod at intervals from left to right; the first inner angle forming rollers and the first outer roller set are correspondingly arranged, three outer rollers in the first outer roller set are respectively arranged on azimuth lines of angles of 60 degrees, 180 degrees and 300 degrees which are perpendicular to the axis of the mandrel, and three inner angle forming rollers in the first inner angle forming rollers are arranged on azimuth lines of angles of 90 degrees, 210 degrees and 330 degrees which are perpendicular to the axis of the mandrel; the second group of inner angle forming rollers and the second group of outer roller groups are correspondingly arranged, three outer rollers in the second group of outer roller groups are respectively arranged on azimuth lines of 0 degree, 120 degrees and 240 degrees which are round in cross section perpendicular to the axis of the mandrel, and three inner angle forming rollers in the second group of inner angle forming rollers are arranged on azimuth lines of 30 degrees, 150 degrees and 270 degrees which are round in cross section perpendicular to the axis of the mandrel; the third inner corner forming roller and the third outer roller set are correspondingly arranged, the fourth inner corner forming roller and the fourth outer roller set are correspondingly arranged, the fifth inner corner forming roller and the fifth outer roller set are correspondingly arranged, and the sixth inner corner forming roller and the sixth outer roller set are correspondingly arranged; the seamless round pipe blank is movably arranged on the blank conveying roller way, the right end of the seamless round pipe blank is fed and sleeved on the left end of the core rod, and the seamless round pipe blank is fed rightward by the seamless round pipe blank feeding mechanism.

The left end of the core rod is provided with a first group of guide roller groups, and the right end of the core rod is provided with a second group of guide roller groups; the number of the guide rollers in the first guide roller group and the number of the guide rollers in the second guide roller group are three.

The central axes of the triangular rolling openings formed by the three outer rollers of each outer roller group are coincident with the central axis of the core rod; a spring is arranged between the guide roller and the core rod, so that the roller surface of the guide roller is attached to the inner surface of the seamless round pipe blank; the right side of the first core rod roller holding device is respectively provided with a second core rod roller holding device and a third core rod roller holding device.

The hot rolling forming method of the thick-wall hexagonal steel pipe capable of improving the corner forming quality comprises a seamless round pipe blank feeding mechanism, a blank conveying roller way, a seamless round pipe blank, a biting roll bending machine frame, a first roll bending machine frame, a second roll bending machine frame, a third roll bending machine frame, a fourth roll bending machine frame, a fifth roll bending machine frame, a sixth roll bending machine frame, a core rod supporting device, a first core rod holding roll device and a core rod; a seamless round pipe blank feeding mechanism is arranged at the left end of the blank conveying roller way, a first core rod roller holding device is arranged at the right end of the blank conveying roller way, and a biting roller bending machine frame, a first roller bending machine frame, a second roller bending machine frame, a third roller bending machine frame, a fourth roller bending machine frame, a fifth roller bending machine frame and a sixth roller bending machine frame are sequentially arranged on the blank conveying roller way at intervals from left to right; the method is characterized by comprising the following steps of:

firstly, determining the caliber of a seamless circular tube blank according to the perimeter of a pre-rolled thick-wall hexagonal steel tube; selecting a core rod according to the caliber of the seamless circular tube blank;

setting a biting outer roll group in a biting roll bending frame, setting a first outer roll group in the first roll bending frame, wherein three outer rolls in the first outer roll group are arranged in a regular triangle, setting a second outer roll group in the second roll bending frame, wherein the three outer rolls in the second outer roll group are arranged in a regular triangle, forming a regular hexagonal rolling opening in space along the left-right direction between the three outer rolls in the first outer roll group and the three outer rolls in the second outer roll group, and respectively determining the installation positions of the biting outer roll group, the three outer rolls in the first outer roll group and the three outer rolls in the second outer roll group according to an outer roll pattern design diagram of the pre-rolled thick-wall hexagonal steel pipe; respectively determining the installation positions of three outer rollers in the third outer roller group and three outer rollers in the fourth outer roller group and the installation positions of three outer rollers in the fifth outer roller group and three outer rollers in the sixth outer roller group by the same method;

a third step of sequentially arranging a first group of inner angle forming rollers, a second group of inner angle forming rollers, a third group of inner angle forming rollers, a fourth group of inner angle forming rollers, a fifth group of inner angle forming rollers and a sixth group of inner angle forming rollers on the core rod at intervals from left to right; according to the internal roll pattern design diagram of the pre-rolled thick-wall hexagonal steel pipe, the installation positions of the internal angle forming rollers of each group on the core rod are respectively determined;

the left end of the core rod sequentially passes through a sixth roll bending frame, a fifth roll bending frame, a fourth roll bending frame, a third roll bending frame, a second roll bending frame, a first roll bending frame and a biting roll bending frame from right to left, and is arranged at the left side of the biting roll bending frame, and the right end of the core rod is arranged in the core rod holding device; arranging a first inner angle forming roller group and a first outer roller group correspondingly, wherein each inner angle forming roller in the first inner angle forming roller group is arranged on an angular bisector of angles of two outer roller groups in the first outer roller group adjacent to the first inner angle forming roller group; the second inner angle forming rollers and the second outer roller groups are correspondingly arranged, and each inner angle forming roller in the second inner angle forming rollers is arranged on an angular bisector of angles of two outer roller groups in the second outer roller groups adjacent to the second inner angle forming rollers; by the same method, the third inner angle forming roller and the third outer roller set are correspondingly arranged, the fourth inner angle forming roller and the fourth outer roller set are correspondingly arranged, the fifth inner angle forming roller and the fifth outer roller set are correspondingly arranged, and the sixth inner angle forming roller and the sixth outer roller set are correspondingly arranged;

fifthly, preheating the seamless steel tube blank to 800-1000 ℃, and sleeving the right end of the preheated seamless steel tube blank on a first group of guide roller groups at the right end of the core rod through a seamless steel tube blank feeding mechanism and a blank conveying roller way; feeding the right end of the preheated seamless round tube blank into a biting outer roller group in a first roller bending frame through a seamless round tube blank feeding mechanism;

a sixth step of conveying the seamless round pipe blank bitten by the bitten outer roller set to the right, feeding the seamless round pipe blank into a triangular rolling port in a first roller bending frame, performing first-pass forming rolling on the right end of the seamless round pipe blank, rolling the right end of the seamless round pipe blank under the combined action of the first outer roller set and the first inner angle forming roller set in the first roller bending frame, and feeding the seamless round pipe blank to the right; when the right end of the seamless circular tube blank enters a triangular rolling port in the second roll bending frame, the right end of the seamless circular tube blank is subjected to second pass forming rolling under the combined action of a second outer roll set and a second inner angle forming roll set in the second roll bending frame.

And the seamless round tube blank rolled by the first roll bending machine frame and the second roll bending machine frame is sequentially sent to a third roll bending machine frame, a fourth roll bending machine frame, a fifth roll bending machine frame and a sixth roll bending machine frame for rolling, and is formed into a thick-wall hexagonal steel tube after six-pass rolling.

A core rod supporting device is arranged between the roll bending frames; before the seamless round tube blank is conveyed from left to right, the mandrel supporting device, the first mandrel holding roller device, the second mandrel holding roller device and the third mandrel holding roller device are in a working state of holding the mandrel tightly; when the seamless round pipe blank is conveyed from left to right, the core rod supporting device, the first core rod holding roller device, the second core rod holding roller device and the third core rod holding roller device are in a working state of loosening the core rod in sequence; after the seamless round tube blank is conveyed from left to right, the mandrel supporting device, the first mandrel holding roller device, the second mandrel holding roller device and the third mandrel holding roller device are in a mandrel holding working state in sequence; the mandrel supporting device, the first mandrel holding device, the second mandrel holding device and the third mandrel holding device are mutually matched to ensure the passing performance of the seamless round tube blank, and simultaneously ensure that the mandrel does not act.

The utility model takes the hot-rolled seamless round tube as a blank, and carries out the rolling forming of the hot-rolled seamless square or rectangular steel tube, thereby greatly improving the forming efficiency of the square tube; the blank is kept at a higher temperature, a small amount of heat compensation can be carried out, namely the temperature required during rolling can be reached, and the energy consumption required by heating the blank is reduced; the mandrel device provided by the utility model realizes continuous gradual roll bending forming of the seamless round tube under the combined action of the outer roll set and the inner roll set, and improves the forming precision of the corner of the square or rectangular steel tube; the radial height of the inner roller arranged on the core rod device can be adjusted through the cushion block, so that one core is multipurpose, and the forming of square tubes or torch tubes with different sizes can be realized.

Drawings

FIG. 1 is a schematic diagram of the structure of the present utility model;

FIG. 2 is a diagram showing the relationship between the mandrel bar 4 and the outer roll sets of each set according to the present utility model;

FIG. 3 is a diagram of the relationship between the first set of outer rolls 19 and the first set of inner corner forming rolls 25 of the present utility model;

fig. 4 is a schematic view showing the structure of a regular hexagonal roll gap 31 formed in the space between the first outer roll set 19 and the second outer roll set 20 according to the present utility model.

Detailed Description

The utility model is described in detail below with reference to the attached drawing figures:

the hot rolling forming tool for the thick-wall hexagonal steel pipe capable of improving the corner forming quality comprises a seamless round pipe blank feeding mechanism 1, a blank conveying roller way 2, a seamless round pipe blank 3, a biting roll bending machine frame 5, a first roll bending machine frame 6, a second roll bending machine frame 7, a third roll bending machine frame 8, a fourth roll bending machine frame 9, a fifth roll bending machine frame 10, a sixth roll bending machine frame 11, a core rod supporting device 15, a first core rod holding roll device 12 and a core rod 4; a seamless round tube blank feeding mechanism 1 is arranged at the left end of a blank conveying roller way 2, a first core rod holding roller device 12 is arranged at the right end of the blank conveying roller way 2, a biting roller bending machine frame 5, a first roller bending machine frame 6, a second roller bending machine frame 7, a third roller bending machine frame 8, a fourth roller bending machine frame 9, a fifth roller bending machine frame 10 and a sixth roller bending machine frame 11 are sequentially arranged at intervals from left to right, a biting outer roller group 18 is arranged in the biting roller bending machine frame 5, and three outer rollers in the biting outer roller group 18 are arranged in a regular triangle; the left end of the mandrel 4 sequentially passes through a sixth roll bending frame 11, a fifth roll bending frame 10, a fourth roll bending frame 9, a third roll bending frame 8, a second roll bending frame 7, a first roll bending frame 6 and a biting roll bending frame 5 from right to left, and is arranged at the left side of the biting roll bending frame 5, and the right end of the mandrel 4 is arranged in a mandrel holding device 12; a first outer roll set 19 is provided in the first roll bending frame 6, three outer rolls in the first outer roll set 19 are arranged in a regular triangle, a second outer roll set 20 is provided in the second roll bending frame 7, three outer rolls in the second outer roll set 20 are also arranged in a regular triangle, and three outer rolls in the first outer roll set 19 and three outer rolls in the second outer roll set 20 form a square rolling port 31 in space in the left-right direction; a third outer roll set 21 is arranged in the third roll bending frame 8, three outer rolls in the third outer roll set 21 are arranged in a regular triangle, a fourth outer roll set 22 is arranged in the fourth roll bending frame 9, three outer rolls in the fourth outer roll set 22 are also arranged in a regular triangle, and a regular hexagonal rolling port is formed in space along the left-right direction between the three outer rolls in the third outer roll set 21 and the three outer rolls in the fourth outer roll set 22; a fifth set of outer rolls 23 is provided in the fifth roll bending frame 10, three outer rolls in the fifth set of outer rolls 23 are arranged in a regular triangle, a sixth set of outer rolls 24 is provided in the sixth roll bending frame 11, three outer rolls in the fifth set of outer rolls 23 are also arranged in a regular triangle, and three outer rolls in the fifth set of outer rolls 23 and three outer rolls in the sixth set of outer rolls 24 form a square rolling port in space in the left-right direction; the mandrel 4 is provided with a first group of interior angle forming rollers 25, a second group of interior angle forming rollers 26, a third group of interior angle forming rollers 27, a fourth group of interior angle forming rollers 28, a fifth group of interior angle forming rollers 29 and a sixth group of interior angle forming rollers 30 at intervals in order from left to right; the first inner angle forming roller set 25 and the first outer roller set 19 are correspondingly arranged, three outer rollers in the first outer roller set 19 are respectively arranged on the azimuth lines of angles of 60 degrees, 180 degrees and 300 degrees which are round in cross section perpendicular to the axis of the mandrel 4, and three inner angle forming rollers in the first inner angle forming roller set (25) are arranged on the azimuth lines of angles of 30 degrees, 150 degrees and 270 degrees which are round in cross section perpendicular to the axis of the mandrel 4; the second set of inner angle forming rollers 26 and the second set of outer rollers 20 are correspondingly arranged, three outer rollers in the second set of outer rollers 20 are respectively arranged on angular azimuth lines of 0 DEG, 120 DEG and 240 DEG which are round in cross section perpendicular to the axis of the mandrel 4, and three inner angle forming rollers in the second set of inner angle forming rollers 26 are arranged on angular azimuth lines of 90 DEG, 210 DEG and 330 DEG which are round in cross section perpendicular to the axis of the mandrel 4; the third inner corner forming roll 27 and the third outer roll set 21 are correspondingly arranged, the fourth inner corner forming roll 28 and the fourth outer roll set 22 are correspondingly arranged, the fifth inner corner forming roll 29 and the fifth outer roll set 23 are correspondingly arranged, and the sixth inner corner forming roll 30 and the sixth outer roll set 24 are correspondingly arranged; on the blank conveying roller way 2, a seamless circular tube blank 3 is movably arranged, the right end of the seamless circular tube blank 3 is fed and sleeved on the left end of the core rod 4, and the seamless circular tube blank 3 is fed rightward by the seamless circular tube blank feeding mechanism 1.

A first guide roller set 16 is arranged at the left end of the core rod 4, and a second guide roller set 17 is arranged at the right end of the core rod 4; the number of guide rollers in the first guide roller set 16 and the number of guide rollers in the second guide roller set 17 are three.

The central axes of the triangular rolling openings formed by the three outer rollers of each outer roller group are overlapped with the central axis of the core rod 4; a spring is arranged between the guide roller and the core rod 4, so that the roller surface of the guide roller is attached to the inner surface of the seamless round tube blank 3; a second mandrel holding device 13 and a third mandrel holding device 14 are respectively arranged on the right side of the first mandrel holding device 12.

The hot rolling forming method of thick-wall hexagonal steel pipe capable of improving corner forming quality comprises a seamless round pipe blank feeding mechanism 1, a blank conveying roller way 2, a seamless round pipe blank 3, a biting roll bending machine frame 5, a first roll bending machine frame 6, a second roll bending machine frame 7, a third roll bending machine frame 8, a fourth roll bending machine frame 9, a fifth roll bending machine frame 10, a sixth roll bending machine frame 11, a core rod supporting device 15, a first core rod holding roll device 12 and a core rod 4; a seamless round tube blank feeding mechanism 1 is arranged at the left end of a blank conveying roller way 2, a first core rod holding roller device 12 is arranged at the right end of the blank conveying roller way 2, and a biting roller bending machine frame 5, a first roller bending machine frame 6, a second roller bending machine frame 7, a third roller bending machine frame 8, a fourth roller bending machine frame 9, a fifth roller bending machine frame 10 and a sixth roller bending machine frame 11 are sequentially arranged at intervals from left to right; the method is characterized by comprising the following steps of:

firstly, determining the caliber of a seamless circular tube blank 3 according to the perimeter of a pre-rolled thick-wall hexagonal steel tube; selecting a core rod 4 according to the caliber of the seamless circular tube blank 3;

a second step of arranging a biting outer roll group 18 in the biting roll bending frame 5, arranging a first group of outer roll groups 19 in the first roll bending frame 6, arranging three outer rolls in the first group of outer roll groups 19 in a regular triangle shape, arranging a second group of outer roll groups 20 in the second roll bending frame 7, arranging three outer rolls in the second group of outer roll groups 20 in a regular triangle shape, and forming a regular hexagonal rolling opening 31 in space along the left-right direction between the three outer rolls in the first group of outer roll groups 19 and the three outer rolls in the second group of outer roll groups 20, and respectively determining the installation positions of the biting outer roll groups 18, the three outer rolls in the first group of outer roll groups 19 and the three outer rolls in the second group of outer roll groups 20 according to the outer roll pattern design diagram of the pre-rolled thick-wall hexagonal steel tube; the installation positions of the three outer rolls in the third outer roll set 21 and the three outer rolls in the fourth outer roll set 22, and the installation positions of the three outer rolls in the fifth outer roll set 23 and the three outer rolls in the sixth outer roll set 24 are respectively determined in the same manner;

a third step of arranging a first group of interior angle forming rollers 25, a second group of interior angle forming rollers 26, a third group of interior angle forming rollers 27, a fourth group of interior angle forming rollers 28, a fifth group of interior angle forming rollers 29 and a sixth group of interior angle forming rollers 30 on the mandrel 4 at intervals in order from left to right; according to the internal roll pattern design diagram of the pre-rolled thick-wall hexagonal steel pipe, the installation positions of the internal angle forming rollers of each group on the core rod 4 are respectively determined;

the left end of the mandrel 4 sequentially passes through a sixth roll bending frame 11, a fifth roll bending frame 10, a fourth roll bending frame 9, a third roll bending frame 8, a second roll bending frame 7, a first roll bending frame 6 and a biting roll bending frame 5 from right to left, and is arranged at the left side of the biting roll bending frame 5, and the right end of the mandrel 4 is arranged in a mandrel holding device 12; the first inner angle forming roller 25 and the first outer roller 19 are correspondingly arranged, three outer rollers in the first outer roller 19 are respectively arranged on the azimuth lines of 60 degrees, 180 degrees and 300 degrees which are round in cross section perpendicular to the axis of the mandrel 4, and three inner angle forming rollers in the first inner angle forming roller 25 are arranged on the azimuth lines of 30 degrees, 150 degrees and 270 degrees which are round in cross section perpendicular to the axis of the mandrel 4; the second set of inner angle forming rollers 26 and the second set of outer rollers 20 are correspondingly arranged, three outer rollers in the second set of outer rollers 20 are respectively arranged on the azimuth lines of 0 DEG, 120 DEG and 240 DEG which are round in cross section perpendicular to the axis of the mandrel 4, and three inner angle forming rollers in the second set of inner angle forming rollers 26 are arranged on the azimuth lines of 90 DEG, 210 DEG and 330 DEG which are round in cross section perpendicular to the axis of the mandrel 4; in the same way, the third inner corner forming roll 27 is arranged corresponding to the third outer roll set 21, the fourth inner corner forming roll 28 is arranged corresponding to the fourth outer roll set 22, the fifth inner corner forming roll 29 is arranged corresponding to the fifth outer roll set 23, and the sixth inner corner forming roll 30 is arranged corresponding to the sixth outer roll set 24;

fifthly, preheating the seamless steel tube blank 3 to 800-1000 ℃, and sleeving the right end of the preheated seamless steel tube blank 3 on a first group of guide roller groups 16 at the right end of the mandrel 4 through a seamless steel tube blank feeding mechanism 1 and a blank conveying roller way 2; feeding the right end of the preheated seamless circular tube blank 3 into a biting outer roller group 18 in a first roller bending frame 5 for biting through a seamless circular tube blank feeding mechanism 1;

sixthly, conveying the seamless pipe blank 3 bitten by the bitten outer roller group 18 rightward into a triangular rolling port in the first roll bending frame 6, performing first-pass forming rolling on the right end of the seamless pipe blank 3, rolling the right end of the seamless pipe blank 3 under the combined action of the first outer roller group 19 and the first inner angle forming roller group 25 in the first roll bending frame 6, and conveying the right end of the seamless pipe blank rightward; when the right end of the seamless circular tube blank 3 enters the triangular rolling port in the second roll bending frame 7, the second pass forming rolling is carried out on the right end of the seamless circular tube blank 3 under the combined action of the second group of outer roll groups 20 and the second group of inner angle forming rolls 26 in the second roll bending frame 7, and the right end of the seamless circular tube blank 3 is rolled into a hexagon.

The seamless round tube blank 3 rolled by the first roll bending machine frame 6 and the second roll bending machine frame 7 is sequentially sent to a third roll bending machine frame 8, a fourth roll bending machine frame 9, a fifth roll bending machine frame 10 and a sixth roll bending machine frame 11 for rolling, and after six passes of rolling, a thick-wall hexagonal steel tube is formed.

Claims (3)

1. The hot rolling forming tool for the thick-wall hexagonal steel pipe comprises a seamless round pipe blank feeding mechanism (1), a blank conveying roller way (2), a seamless round pipe blank (3), a biting roll bending machine frame (5), a first roll bending machine frame (6), a second roll bending machine frame (7), a third roll bending machine frame (8), a fourth roll bending machine frame (9), a fifth roll bending machine frame (10), a sixth roll bending machine frame (11), a core rod supporting device (15), a first core rod holding roll device (12) and a core rod (4); a seamless round tube blank feeding mechanism (1) is arranged at the left end of a blank conveying roller way (2), a first core rod holding roller device (12) is arranged at the right end of the blank conveying roller way (2), and a biting roller bending machine frame (5), a first roller bending machine frame (6), a second roller bending machine frame (7), a third roller bending machine frame (8), a fourth roller bending machine frame (9), a fifth roller bending machine frame (10) and a sixth roller bending machine frame (11) are sequentially arranged at intervals from left to right; the device is characterized in that a biting outer roller group (18) is arranged in a biting roller bending frame (5), and three outer rollers in the biting outer roller group (18) are arranged in a regular triangle; the left end of the core rod (4) sequentially passes through a sixth roll bending frame (11), a fifth roll bending frame (10), a fourth roll bending frame (9), a third roll bending frame (8), a second roll bending frame (7), a first roll bending frame (6) and a biting roll bending frame (5) from right to left, and is arranged at the left side of the biting roll bending frame (5), and the right end of the core rod (4) is arranged in a core rod holding roll device (12); a first outer roller set (19) is arranged in the first roller bending frame (6), three outer rollers in the first outer roller set (19) are arranged in a regular triangle, a second outer roller set (20) is arranged in the second roller bending frame (7), three outer rollers in the second outer roller set (20) are also arranged in a regular triangle, and a regular hexagonal rolling opening (31) is formed in space along the left-right direction between the three outer rollers in the first outer roller set (19) and the three outer rollers in the second outer roller set (20); a third outer roller set (21) is arranged in the third roller bending frame (8), three outer rollers in the third outer roller set (21) are arranged in a regular triangle, a fourth outer roller set (22) is arranged in the fourth roller bending frame (9), three outer rollers in the fourth outer roller set (22) are also arranged in a regular triangle, and a regular hexagonal rolling port is formed in space along the left-right direction between the three outer rollers in the third outer roller set (21) and the three outer rollers in the fourth outer roller set (22); a fifth outer roller set (23) is arranged in the fifth roller bending frame (10), three outer rollers in the fifth outer roller set (23) are arranged in a regular triangle, a sixth outer roller set (24) is arranged in the sixth roller bending frame (11), the three outer rollers in the fifth outer roller set (23) are also arranged in a regular triangle, and a regular hexagonal rolling opening is formed in space along the left-right direction between the three outer rollers in the fifth outer roller set (23) and the three outer rollers in the sixth outer roller set (24); a first group of inner angle forming rollers (25), a second group of inner angle forming rollers (26), a third group of inner angle forming rollers (27), a fourth group of inner angle forming rollers (28), a fifth group of inner angle forming rollers (29) and a sixth group of inner angle forming rollers (30) are sequentially arranged on the core rod (4) at intervals from left to right; the first inner angle forming rollers (25) and the first outer roller groups (19) are correspondingly arranged, three outer rollers in the first outer roller groups (19) are respectively arranged on azimuth lines with angles of 60 degrees, 180 degrees and 300 degrees which are round in cross section perpendicular to the axis of the mandrel (4), and three inner angle forming rollers in the first inner angle forming rollers (25) are arranged on azimuth lines with angles of 90 degrees, 210 degrees and 330 degrees which are round in cross section perpendicular to the axis of the mandrel (4); the second group of inner angle forming rollers (26) and the second group of outer roller groups (20) are correspondingly arranged, three outer rollers in the second group of outer roller groups (20) are respectively arranged on azimuth lines with angles of 0 DEG, 120 DEG and 240 DEG which are round in cross section perpendicular to the axis of the mandrel (4), and three inner angle forming rollers in the second group of inner angle forming rollers (26) are arranged on azimuth lines with angles of 30 DEG, 150 DEG and 270 DEG which are round in cross section perpendicular to the axis of the mandrel (4); the third inner angle forming roller (27) and the third outer roller set (21) are correspondingly arranged, the fourth inner angle forming roller (28) and the fourth outer roller set (22) are correspondingly arranged, the fifth inner angle forming roller (29) and the fifth outer roller set (23) are correspondingly arranged, and the sixth inner angle forming roller (30) and the sixth outer roller set (24) are correspondingly arranged; on the blank conveying roller way (2), a seamless circular tube blank (3) is movably arranged, the right end of the seamless circular tube blank (3) is fed and sleeved on the left end of the core rod (4), and the seamless circular tube blank (3) is fed rightward by the seamless circular tube blank feeding mechanism (1).

2. The hot rolling forming tool for the thick-wall hexagonal steel pipe capable of improving the forming quality of corners according to claim 1 is characterized in that a first group of guide roller groups (16) are arranged at the left end of a core rod (4), and a second group of guide roller groups (17) are arranged at the right end of the core rod (4); the number of the guide rollers in the first guide roller group (16) and the number of the guide rollers in the second guide roller group (17) are three.

3. The hot rolling forming tool for the thick-wall hexagonal steel pipe capable of improving the forming quality of corners according to claim 2, wherein the central axis of a triangular rolling port surrounded by three outer rollers of each outer roller group is coincident with the central axis of a core rod (4); a spring is arranged between the guide roller and the core rod (4) to enable the roller surface of the guide roller to be attached to the inner surface of the seamless round pipe blank (3); the right side of the first core rod holding roller device (12) is respectively provided with a second core rod holding roller device (13) and a third core rod holding roller device (14).

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