A kind of equipment for producing stainless steel pipe by rear-mounted limiting mandrel continuous pipe mill train

Abstract

The utility model belongs to the field of seamless steel tube production and processing technology especially relates to a kind of equipment of post-positioned limited mandrel pilger mill production stainless steel pipe, the equipment includes heating furnace, piercer, pilger mill set, secondary heating furnace, multiple rack sizing unit, stepping cooling bed, straightening unit;The pilger mill set includes quick transverse moving device, front desk feeding mechanism, lubrication transmission mandrel roller way, online mandrel preheating lubricating device, stepping mandrel cooling bed, mandrel back-off cooling roller way, cooled mandrel transmission roller way, pilger mill, pipe removing sizing unit, roll holder and material transfer mechanism, limited mandrel mechanism;The equipment of post-positioned limited mandrel pilger mill production stainless steel pipe provided by the utility model, the overall hardness of its mandrel is high, the temperature drop of the inner wall of the blank pipe is small before rolling, the stress of the mandrel is distributed along the longitudinal direction when rolling, the rolling speed is fast, the efficiency is high, the production finished product precision is high, and it is suitable for producing difficult-to-deform stainless steel pipe and composite steel pipe.

Description

Technical Field

[0001] This utility model belongs to the field of seamless steel pipe production and processing technology, and in particular relates to a set of equipment for producing stainless steel pipes by a rear-mounted limited mandrel continuous rolling mill. Background Technology

[0002] Currently, my country's seamless steel pipe hot-working production mainly employs two rolling methods: skew rolling and longitudinal rolling. Skew rolling equipment primarily includes two-roll Accu-Roll mills and three-roll Assel mills; however, both types of equipment can mostly only produce steel pipes of ordinary quality. Longitudinal rolling equipment includes automatic rolling mills, mandrel continuous rolling mills, floating mandrel continuous rolling mills, and CPE jacking mills, etc.

[0003] Automatic tube rolling mill (ball rolling) requires the steel pipe to be continuously rotated 180° during operation. The temperature difference between the steel pipe before and after rotation causes the product to always have a wall thickness deviation. The produced products can only be used for ordinary fluid civil steel pipes.

[0004] CPE pipe jacking units, due to the configuration of their molds and the cost of manufacturing and maintaining long mandrels, result in excessive overall equipment investment and high production costs, which are generally difficult for enterprises to bear.

[0005] In existing continuous rolling mills with limited-movement mandrels, the limited-movement mandrel device is located at the front of the mill. The rolling process requires threading the mandrel through the tube before rolling. The low-temperature mandrel and mandrel assembly cause a rapid drop in the inner wall temperature of the tube after threading, which affects the stability of subsequent rolling operations and the overall rolling effect of the tube. Furthermore, during rolling, the mandrel and mandrel assembly are subjected to extremely high tensile and frictional forces in the longitudinal direction, making the mandrel highly susceptible to wear. This is especially true when rolling small-diameter seamless steel pipes, where the mandrel-mandrel connection point is prone to breakage, thus affecting the overall operational stability of the equipment and increasing maintenance costs. Specifically… Traditional front-insertion mandrels, with a hardness of HRC40~42° and a length of about 4~7 meters, are convenient to use in heat treatment and straightening operations. However, when rolling stainless steel with high rolling stress (1.5~2 times that of carbon steel), the mandrel wears faster during rolling. After the outer wall of the mandrel wears down, the longitudinal rolling stress at the mandrel-mandrel connection point increases, making it prone to breakage. Some manufacturers use chrome plating to address the mandrel wear problem, but during rolling, the mandrel itself has a low hardness (lower than the hardness of the chrome plating), which can cause the chrome plating to peel off.

[0006] Therefore, given the market's urgent need for high-value-added stainless steel pipe products, the hot-rolling production process of stainless steel pipes urgently requires improvements in the wear resistance and impact resistance of the mandrel. In light of the national steel industry's green and environmentally friendly requirements for hot-rolled seamless steel pipe production ("replacing cold with hot rolling"), and the demand for producing high-value-added stainless steel, high-alloy steel, and composite steel pipes, there is an urgent need for a production process and equipment that requires less investment, minimizes tool wear, shortens the process time, and increases efficiency to solve the aforementioned technical problems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this utility model provides equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill.

[0008] The technical solution of this utility model is: an equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill, the equipment including a heating furnace, a piercing mill, a continuous rolling mill, a secondary heating furnace, a multi-stand sizing mill, a walking beam cooling bed, and a straightening unit.

[0009] The continuous rolling mill includes a rapid traverse device, a front-end feeding mechanism, a lubrication and transmission mandrel roller table, an online mandrel preheating and lubrication device, a walking mandrel cooling bed, a mandrel return cooling roller table, a cooled mandrel transmission roller table, a continuous rolling mill, a tube removal and sizing unit, a roll clamping frame and material transfer mechanism, and a mandrel limiting mechanism.

[0010] The continuous rolling mill adopts a "1+5 stand continuous rolling process", which includes one air shrink stand and five main deformation equipment.

[0011] The limiting mandrel mechanism includes a working frame, a hydraulic limiting device, or a rack and pinion limiting device.

[0012] A tube removal and sizing unit is provided on one side of the continuous rolling mill outlet. The front end of the roll clamping frame and the material transfer mechanism is located close to the tube removal and sizing unit, and the limiting mandrel mechanism is located at the rear end of the roll clamping frame and the material transfer mechanism.

[0013] The front-end feeding mechanism is installed on the other side of the continuous rolling mill, and the rapid traverse device is set between the piercing mill and the front-end feeding mechanism; the mandrel return cooling roller conveyor and the lubrication transmission mandrel roller conveyor are respectively set on both sides of the front-end feeding mechanism; the stepping mandrel cooling bed is set at the tail end of the mandrel return cooling roller conveyor; the cooled mandrel transmission roller conveyor is set at the front end of the lubrication transmission mandrel roller conveyor; the online mandrel preheating and lubrication device is installed between the cooled mandrel transmission roller conveyor and the lubrication transmission mandrel roller conveyor.

[0014] Furthermore, a roller clamping frame and a material conveying mechanism are provided behind the tube removal and sizing unit. The roller clamping frame and material conveying mechanism are provided with multiple sets of roller clamping frames. The roller clamping frames adopt a three-roll annular die structure (the gap is reasonably designed according to the diameter of the rolled steel pipe and the diameter of the mandrel). The multiple sets of roller clamping frames are respectively installed on the working frame. The rolling center line of the multiple sets of roller clamping frames is consistent with the rolling center line of the continuous rolling mill and the tube removal and sizing unit. Multiple sets of support roller devices are horizontally installed between the roller clamping frames. One end of all the support roller devices is connected by a connecting rod and can be adjusted and raised. The other end is connected to the drive shaft, and the drive shaft is externally connected to a transmission device.

[0015] Furthermore, the front-end feeding mechanism is located at the entrance of the continuous rolling mill, with a pneumatic feeding device on one side and a trolley frame on the other side, on which a mandrel trolley is mounted; the pneumatic feeding device includes an opening and closing horn-mouth limiting device, a double horn-mouth guide cylinder, a pneumatic feeding linear bearing device guide column, and a feeding cylinder; both the trolley frame and the pneumatic feeding device are equipped with several conveying rollers, and all of the conveying rollers form the receiving trough of the front-end feeding mechanism.

[0016] Furthermore, the limiting mandrel mechanism is a rear-mounted type, including a working frame, a hydraulic limiting device, or a rack and pinion limiting device.

[0017] Furthermore, the length of the mandrel used for limiting movement in the limiting mandrel mechanism is 6-8 meters, and the hardness of the mandrel is 45-55°.

[0018] The beneficial effects of this utility model are:

[0019] 1. Compared with the existing front-mounted (front-insertion) mandrel continuous rolling mill, the rear-mounted mandrel continuous rolling mill unit provided by this utility model has the following advantages: The front-insertion mandrel mechanism requires the tube to be threaded through the mandrel before being pushed into the continuous rolling mill for rolling. Before the threading operation, the temperature of the mandrel and mandrel assembly is relatively low (around 100~260°C). After the mandrel is threaded through the tube, the temperature of the inner wall of the tube will drop rapidly. The preparation time between the threading of the tube and the rolling of the tube is relatively long, which will lead to a large deviation in the internal and external temperature of the tube during rolling, thus affecting the stability of the rolling operation. In the design of this utility model, the mandrel mechanism is located at the rear, and the threading of the tube and the rolling are carried out simultaneously, which can ensure the temperature of the tube during rolling (small temperature drop of the inner wall of the tube), and ensure the stability of the rolling operation.

[0020] 2. The rear-mounted mandrel-controlled continuous rolling mill unit provided by this utility model, based on data obtained from multiple company tests, shows that by placing the mandrel-controlled device at the rear, the mandrel hardness can be increased to HRC45~55. During rolling operations, the mandrel's movement is restricted along the rolling direction, reducing mandrel friction (rolling resistance). Consequently, the force at the mandrel-mandrel connection point decreases, thus reducing rolling failures caused by mandrel-mandrel connection point breakage in front-mounted (front-insertion) mandrel-controlled continuous rolling mill units. Simultaneously, it significantly reduces mandrel wear and maintenance costs, improves production pace and rolling stability, and effectively extends the mandrel's service life (experimental data shows a significant increase in mandrel service life).

[0021] 3. The rear-mounted limited-motion mandrel continuous rolling mill unit provided by this utility model adopts an open-type clamping roll stand with multiple sets of annular perforations in the rear. Compared with the discharge trough of the rear conveyor roller table in traditional continuous rolling mills, this rolling is longitudinal straight rolling. Traditional clamping roll stands are suitable for rotating skew rolling mills, but cannot be used for straight rolling mills. Before rolling the steel pipe, the annular perforation clamping roll stand plays the role of clamping the mandrel, ensuring the stability of the mandrel during rolling and preventing the mandrel from bending and deforming. Then, during rolling, the gap between the partially opened annular perforation and the diameter of the rolled steel pipe is 2~4mm on one side. At the same time, the annular perforation passively rotates in the same direction as the rolling direction of the steel pipe, which can reduce the friction between the steel pipe and the workpiece during high-speed rolling, ensure the surface smoothness of the steel pipe, and improve product quality.

[0022] 4. The rear-mounted limited-movement mandrel continuous rolling mill unit provided by this utility model, compared with the traditional three-stand tube removal and sizing mill in the back row of the continuous rolling mill, has a tube removal and sizing mill unit with 3 to 7 stands. Through the design of the pass shape of the process parameters, it can realize the separation of the tube and the mandrel during rolling, and at the same time increase the reduction rate. It can perform large reduction in diameter during high-temperature rolling, and directly produce finished tubes with large reduction rates. It can meet the requirements of direct finished products of steel pipes made of difficult-to-deform materials such as stainless steel, high alloy steel, and composite steel pipes. It can also reduce the reheating and rolling costs of subsequent production processes, save energy and reduce consumption, and improve product production efficiency. It is in line with the green and energy-saving direction of "using heat instead of cold" proposed by the national steel industry for the production of hot-rolled seamless steel pipes, and also improves the production efficiency and benefits of enterprises.

[0023] In summary, the equipment provided by this utility model for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill has the advantages of low temperature drop before tube rolling, low die wear, fast rolling speed, high efficiency, and high precision. It can directly hot roll out finished products and is suitable for producing stainless steel seamless pipes of various difficult-to-deform materials. Attached Figure Description

[0024] Figure 1 This is a plan view of the continuous rolling mill unit in this utility model;

[0025] Figure 1-1 for Figure 1 Enlarged view of a section of a stepper mandrel cooling bed;

[0026] Figure 1-2 for Figure 1 Enlarged view of section one of the front-end material feeding mechanism;

[0027] Figure 1-3 for Figure 1 Enlarged view of the intermediate continuous rolling mill and its back-end section;

[0028] Figure 2-1 This is the floor plan of Implementation Plan 1;

[0029] Figure 2-2 This is the floor plan for Scheme Two;

[0030] Figure 3-1 This is a schematic diagram of the main structure of the mandrel limiting mechanism;

[0031] Figure 3-2 This is a side view schematic diagram of the limited-motion mandrel mechanism;

[0032] Figure 3-3 A top view schematic diagram of the limited-motion mandrel mechanism;

[0033] Figure 4-1 This is a schematic diagram of the main structure of the roller clamping frame and the material transfer mechanism.

[0034] Figure 4-2 Views of the roller clamping machine frame;

[0035] Figure 5-1 This is a schematic diagram of the main structure of the front-end material feeding mechanism.

[0036] Figure 5-2 A top-view structural diagram of the front-end feeding mechanism;

[0037] Figure 6-1 This is a schematic diagram of the main structure of the pneumatic feeding device.

[0038] Figure 6-2 This is a top view schematic diagram of the pneumatic feeding device.

[0039] Figure 7-1 This is a top view of the rapid lateral movement device.

[0040] Figure 7-2 This is a schematic diagram of the main structure of the rapid lateral movement device;

[0041] Figure 7-3 This is a side view of the rapid lateral movement device.

[0042] Figure 8 This is a schematic diagram of a stepper mandrel cooling bed.

[0043] Figure reference numerals: J, heating furnace; J01, piercing mill; L, continuous rolling mill; 1, continuous rolling mill; 2, tube stripping and sizing mill; 3, roller holder and material transfer mechanism; 4, mandrel limiting mechanism; 5, front-end feeding mechanism; 6, mandrel return cooling roller conveyor; 7, walking mandrel cooling bed; 8, mandrel cooling post-transfer roller conveyor; 9, online mandrel preheating and lubrication device; 10, lubrication and transfer mandrel roller conveyor; 11, secondary heating furnace; 12, rapid traverse device; 13, continuous rolling post-transfer device; 14, online medium frequency or tunnel furnace reheating device; 15, pre-sizing conveyor roller conveyor; 16, multi-stand sizing mill; 17, post-sizing conveyor roller conveyor; 18, walking cooling bed; 19, straightening unit;

[0044] 301. Roller clamping frame; 302. Roller clamping; 303. Roller clamping arm connecting rod; 304. Roller clamping frame cylinder or hydraulic cylinder; 305. Roller clamping frame mounting base; 306. Discharge lifting roller mechanism;

[0045] 401. Hydraulic limiting cylinder; 402. Core rod protection device; 403. Core rod limiting and locking device; 404. Limiting protection device;

[0046] 51. Pneumatic feeding device; 501. Opening and closing horn mouth limiting device; 502. Double horn mouth guide cylinder; 503. Pneumatic feeding linear bearing device guide column; 504. Feeding cylinder;

[0047] 505. Mandrel trolley; 506. Conveyor roller;

[0048] 601. Mandrel retraction cooling roller conveyor backstage turning device;

[0049] 121. Working frame; 122. Moving crossbeam hook; 123. Crossbeam drive motor and reducer assembly; 124. Moving crossbeam rollers;

[0050] 20. Pipes; 21. Mandrel and mandrel assembly. Detailed Implementation

[0051] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present invention or its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0052] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0053] See Figure 1-8 A type of equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill, comprising a heating furnace J, a piercing mill J01, a continuous rolling mill L, a secondary heating furnace 11, a multi-stand sizing mill 17, a walking beam cooling bed 18, and a straightening mill 19.

[0054] The continuous rolling mill L includes a rapid traverse device 12, a front-end feeding mechanism 5, a lubrication and transmission mandrel roller table 10, an online mandrel preheating and lubrication device 9, a walking mandrel cooling bed 7, a mandrel return cooling roller table 6, a cooled mandrel transmission roller table 8, a continuous rolling mill 1, a tube removal and sizing unit 2, a roll clamping frame and material transfer mechanism 3, and a mandrel limiting mechanism 4.

[0055] The continuous rolling mill adopts the "1+5 stand continuous rolling process", which includes one air shrink stand and five main deformation equipment;

[0056] The limiting mandrel mechanism 4 includes a working frame and a hydraulic limiting device or a rack and pinion limiting device;

[0057] A tube removal and sizing unit 2 is provided on one side of the outlet of the continuous rolling mill 1. The front end of the roll clamping frame and the material transfer mechanism 3 is located close to the tube removal and sizing unit 2, and the limiting mandrel mechanism 4 is located at the rear end of the roll clamping frame and the material transfer mechanism 3.

[0058] The front-end feeding mechanism 5 is installed on the other side of the continuous rolling mill 1, and the rapid transverse transfer device 12 is set between the piercing mill J01 and the front-end feeding mechanism 5; the mandrel return cooling roller conveyor 6 and the lubrication transfer mandrel roller conveyor 10 are respectively set on both sides of the front-end feeding mechanism 5; the stepping mandrel cooling bed 7 is set at the tail end of the mandrel return cooling roller conveyor 6; the cooled mandrel transfer roller conveyor 8 is set at the front end of the lubrication transfer mandrel roller conveyor 10; the online mandrel preheating and lubrication device 9 is installed between the cooled mandrel transfer roller conveyor 8 and the lubrication transfer mandrel roller conveyor 10.

[0059] Specifically, a roller clamping frame and a material transfer mechanism 3 are installed behind the tube removal and sizing unit 2. The roller clamping frame and material transfer mechanism 3 are equipped with multiple sets of roller clamping frames 301. The roller clamping frames 301 adopt a three-roll annular die structure (the gap is reasonably designed according to the diameter of the rolled steel pipe and the diameter of the mandrel). The multiple sets of roller clamping frames 301 are installed on the working frame respectively. The rolling center line of the multiple sets of roller clamping frames 301 is consistent with the rolling center line of the continuous rolling mill 1 and the tube removal and sizing unit 2. Multiple sets of roller support devices are horizontally installed between the roller clamping frames 301. One end of all roller support devices is connected by a connecting rod and can be adjusted and raised. The other end is connected to the drive shaft, and the drive shaft is externally connected to a transmission device.

[0060] Specifically, the front-end feeding mechanism 5 is located at the entrance of the continuous rolling mill 1. One side of it is a pneumatic feeding device 51, and the other side is a trolley frame. The trolley frame is equipped with a mandrel trolley 505. The pneumatic feeding device 51 includes an opening and closing horn-mouth limiting device 501, a double horn-mouth guide cylinder 502, a pneumatic feeding linear bearing device guide column 503, and a feeding cylinder 504. Both the trolley frame and the pneumatic feeding device 51 are equipped with several transmission rollers 506. All the transmission rollers 506 form the receiving trough of the front-end feeding mechanism 5.

[0061] Specifically, the limiting mandrel mechanism 4 is a rear-mounted type, including a working frame, a hydraulic limiting device, or a rack and pinion limiting device.

[0062] Specifically, the length of the mandrel used by the limiting mandrel mechanism 4 is 6-8 meters, and the hardness of the mandrel is 45-55°.

[0063] Some implementation methods of the mandrel carriage 505:

[0064] The mandrel carriage 505 is mounted on the trolley frame. The motor and reducer of the carriage are installed on the upper part of the mandrel carriage. The reducer operates by meshing with the rack mounted on the trolley frame through the gear output from the lower part, or by driving the reducer through the motor to drive the front and rear double sprockets. The chains on both sides link the mandrel carriage to achieve rapid forward and backward movement.

[0065] The process flow used in this equipment is as follows:

[0066] S1: Install the limiting mandrel mechanism 4 in the rolling exit direction of the continuous rolling mill 1 and the tube removal and sizing unit 2;

[0067] S2: Piercing. The tube blank is heated to not less than 1200°C in the heating furnace J, and then pierced by the piercing mill J01 to form a tube. When producing thin-walled tubes, if the tube temperature is not suitable for hot rolling, it can enter the secondary heating furnace 11 located between the piercing mill J01 and the front of the continuous rolling mill 1 for online heating to raise the tube temperature to the rolling temperature.

[0068] S3: The mandrel and mandrel assembly 21, after preheating and lubrication, are fed into the receiving trough of the front-end feeding mechanism 5 of the continuous rolling mill 1 via the front-end turning device. The mandrel trolley 505 in the front-end feeding mechanism 5 presses the mandrel and sends it into the limiting mandrel mechanism 4 in the back-end of the continuous rolling mill 1. The limiting mandrel mechanism 4 presses and limits the mandrel. The roll clamping frame 301 in the back-end of the continuous rolling mill 1 clamps the mandrel to a suitable rolling center position. The pierced tube enters the front-end feeding mechanism 5 of the continuous rolling mill 1 via the rapid lateral movement device 12. The feeding cylinder 504 pushes the tube forward through the double-horn guide cylinder 502 to insert the mandrel (e.g., ...). Figure 6-1 As shown in the figure, the arrow indicates the reciprocating section of the double-horn guide cylinder. There is an open horn-mouth limiting device 501 at the front inlet of the continuous rolling mill 1. This device is in a closed state before bar threading and tube feeding.

[0069] S4: Continuous rolling mill with limited movement. The inlet of continuous rolling mill 1 opens the open horn-shaped limiting device 501, and the feeding cylinder 504 pushes the double horn guide cylinder 502 to feed the tube into continuous rolling mill 1 for the limited movement mandrel insertion and tube rolling. At the same time, the roller holder 301 opens and closes according to the diameter of the steel pipe after continuous rolling. After the tube is reduced in diameter and wall thickness, it is deformed. At the same time, the tube sizing unit 2 further reduces the diameter of the tube after continuous rolling and deforms it into the required finished tube size or the tube before cold working.

[0070] S5: Mandrel retraction and steel pipe delivery. The rolled steel pipe is sent to the position before the movement restriction by the roller support device in the clamping roller and material transfer mechanism 5. After the rolling is completed, the mandrel is pulled from the continuous rolling mill 1 to the receiving groove of the front feeding mechanism by the mandrel trolley 505 in the front feeding mechanism 5. Then the mandrel trolley 505 releases the mandrel, and the mandrel flows into the mandrel retraction cooling roller table 6 through the turning device and is conveyed to one side of the walking mandrel cooling bed 7. Then the mandrel is turned to the walking mandrel cooling bed 7 for storage and cooling by the turning device. At the same time, the lubricated second mandrel and mandrel assembly 21 enter the receiving groove of the front feeding mechanism 5 through the turning device and are sent to the limiting position of the movement restriction mandrel mechanism 4 by the mandrel trolley 505. The tube is moved laterally by the rapid traverse device 12 to the receiving groove position of the front feeding mechanism 5 to wait for rolling. Then the continuous rolling operation is repeated. The whole device is automated by electrical PLC and detection device.

[0071] S6: The steel pipe after continuous rolling can be rolled and sizing in a second time. After the steel pipe has been processed by the continuous rolling mill 1 and the pipe sizing unit 2, it needs to be deformed again to produce the required product. It can be heated twice by the conveyor roller table and then enter the multi-stand sizing unit 16 for rolling. After the diameter is reduced, the required finished steel pipe is obtained.

[0072] S7: Cooling. After the steel pipe has been rolled twice, it is conveyed to the walking cooling bed 18 via the conveyor roller 17 after sizing.

[0073] S8: Finished product collection. After cooling, the finished pipes are straightened, cut off, inspected, packaged, marked, and put into storage, thus completing the collection of finished pipes.

[0074] Specifically, the limiting mandrel mechanism 4 in S1 is a rear-mounted type, located in the back row of the continuous rolling mill, and its limiting method can be hydraulic limiting or rack limiting.

[0075] Specifically, the length of the mandrel used for limiting movement in S3 is 6-8 meters, and the hardness of the mandrel is 45-55°.

[0076] As some implementation methods of various material turning devices in this process: see [reference] Figure 8 Each material turning device can refer to the structure of the mandrel return cooling roller table backstage turning device 601 in the figure, or use it directly, or make some modifications.

[0077] Implementation Plan 1:

[0078] Within a factory of appropriate size, in accordance with... Figure 2-1 As shown, the equipment used includes: heating furnace J, piercing mill J01, continuous rolling mill L, continuous rolling post-transfer device 13, online medium frequency or tunnel furnace reheating device 14, pre-sizing conveyor roller table 15, multi-stand sizing mill 16, post-sizing conveyor roller table 17, walking beam cooling bed 18, and straightening unit 19.

[0079] Reference Figure 1 , Figure 2-1 A type of equipment for a rear-mounted mandrel continuous rolling mill includes a rapid traverse device 12 that is parallel to the rolling line of the piercing mill J01 and can move laterally back and forth above the rolling line of the mill's front end, and a secondary heating furnace 11 that is also parallel to the rapid traverse device 12 and is arranged between the piercing mill J01 and the mill's front end; the continuous rolling mill L has a front end feeding mechanism 5, a mandrel return roller conveyor 6, a walking mandrel cooling bed 7, a mandrel cooling post-transfer roller conveyor 8, and an online mandrel preheating and lubrication device 9 arranged sequentially on one side of the front end of its continuous rolling mill 1. The continuous rolling mill L has a tube removal and sizing unit 2, a roll clamping frame and material transfer mechanism 3, and a limiting mandrel mechanism 4 arranged sequentially on one side of the back row of the continuous rolling mill 1; on the side parallel to the roll clamping frame and material transfer mechanism 3 in the back row of the continuous rolling mill 1, the following are arranged sequentially: a post-continuous rolling material transfer device 13, an online medium frequency or tunnel furnace reheating device 14, a pre-sizing conveyor roller table 15, a multi-stand sizing unit 16, a post-sizing conveyor roller table 17, a walking beam cooling bed 18, and a straightening unit 19; the hot rolling production line for seamless steel pipes is arranged in the above manner.

[0080] Some implementations of the roller clamp and material transfer mechanism 3:

[0081] like Figure 4-1 , 4-2As shown, the equipment includes a roller clamping frame 301, a roller clamping mechanism 302, a roller clamping arm connecting rod 303, a roller clamping frame cylinder or hydraulic cylinder 304, a roller clamping frame mounting base 305, and a discharge lifting roller mechanism 306.

[0082] Some implementation methods of the limiting mandrel mechanism 4:

[0083] like Figure 3-1 , 3-2 3-3, the limiting mandrel mechanism adopts a hydraulic limiting device, which includes a hydraulic limiting cylinder 401, a mandrel protection device 402, a mandrel limiting locking device 403, and a limiting protection device 404.

[0084] If the limiting mandrel mechanism 4 adopts a rack and pinion limiting device, it can be a limiting rack, gear, transverse mechanism or other equipment.

[0085] Implementation Plan Two:

[0086] Within a factory of appropriate size, in accordance with... Figure 2-2 As shown, the equipment used includes: heating furnace J, piercing mill J01, continuous rolling mill L, continuous rolling post-transfer device 13, sizing post-transfer roller table 17, walking beam cooling bed 18, and straightening unit 19.

[0087] Reference Figure 1 , Figure 2-2 A type of equipment for a rear-mounted mandrel-controlled continuous rolling mill includes a rapid traverse device 12 that moves laterally back and forth above the rolling line of the piercing mill J01 and above the rolling line of the mill's front end, and a secondary heating furnace 11 that is also arranged parallel to the rapid traverse device 12 between the piercing mill J01 and the mill's front end; the continuous rolling mill L has a front end feeding mechanism 5, a mandrel return roller table 6, a walking mandrel cooling bed 7, a mandrel cooling post-transfer roller table 8, an online mandrel preheating and lubrication device 9, and a lubrication and transfer mandrel roller table 10 arranged sequentially on the front end side of the continuous rolling mill L; the continuous rolling mill L has a tube removal and sizing unit 2, a roll clamping frame and material transfer mechanism 3, and a mandrel-controlled mechanism 4 arranged sequentially on the back end side of the continuous rolling mill L; and a rear transfer roller table 17, a walking cooling bed 18, and a straightening unit 19 arranged sequentially on the side parallel to the roll clamping frame and material transfer mechanism 3 on the back end side of the continuous rolling mill 1; a hot rolling production line for seamless steel pipes is arranged in the above manner.

[0088] Based on this process flow, it can be seen that, according to the needs of producing different steel pipe products, the technical solution of Implementation Scheme 1 can perform a second sizing and shaping on the steel pipe after continuous rolling, that is, secondary rolling; while the technical solution of Implementation Scheme 2 does not require secondary rolling of the steel pipe after continuous rolling.

[0089] The various embodiments of this utility model have now been described in detail. To avoid obscuring the concept of this utility model, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0090] The embodiments described above only illustrate some implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model.

Claims

1. Equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill, characterized in that: The equipment includes a heating furnace (J), a piercing mill (J01), a continuous rolling mill (L), a secondary heating furnace (11), a multi-stand sizing mill (17), a walking beam cooling bed (18), and a straightening mill (19). The continuous rolling mill (L) includes a rapid traverse device (12), a front-end feeding mechanism (5), a lubrication and transmission mandrel roller table (10), an online mandrel preheating and lubrication device (9), a walking mandrel cooling bed (7), a mandrel return cooling roller table (6), a cooled mandrel transmission roller table (8), a continuous rolling mill (1), a tube removal and sizing unit (2), a roll holder and material transfer mechanism (3), and a mandrel limiting mechanism (4). The continuous rolling mill (1) includes one air compressor stand and five main deformation equipment stands; The limiting mandrel mechanism (4) includes a working frame, a hydraulic limiting device or a rack and pinion limiting device; The continuous rolling mill (1) is provided with a tube removal and sizing unit (2) on the outlet side. The front end of the roll clamping frame and material transfer mechanism (3) is located close to the tube removal and sizing unit (2). The limiting mandrel mechanism (4) is located at the rear end of the roll clamping frame and material transfer mechanism (3). The front feeding mechanism (5) is installed on the other side of the continuous rolling mill (1), and the rapid transverse device (12) is set between the piercing mill (J01) and the front feeding mechanism (5); the mandrel return cooling roller table (6) and the lubrication transmission mandrel roller table (10) are respectively set on both sides of the front feeding mechanism (5); the stepping mandrel cooling cooling bed (7) is set at the tail end of the mandrel return cooling roller table (6); the cooled mandrel transmission roller table (8) is set at the front end of the lubrication transmission mandrel roller table (10); the online mandrel preheating and lubrication device (9) is installed between the cooled mandrel transmission roller table (8) and the lubrication transmission mandrel roller table (10).

2. The equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill as described in claim 1, characterized in that: The tube removal and sizing mill (2) is equipped with a roller clamping frame and a material transfer mechanism (3) at the rear. The roller clamping frame and material transfer mechanism (3) are equipped with multiple sets of roller clamping frames (301). The roller clamping frames (301) adopt a three-roll annular hole structure. The multiple sets of roller clamping frames (301) are respectively installed on the working frame. The rolling center line of the multiple sets of roller clamping frames (301) is consistent with the rolling center line of the continuous rolling mill (1) and the tube removal and sizing mill (2). Multiple sets of roller support devices are horizontally installed between the roller clamping frames (301). One end of all the roller support devices is connected by a connecting rod and can be adjusted and raised. The other end is connected to the drive shaft. The drive shaft is externally connected to a transmission device.

3. The equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill as described in claim 1, characterized in that: The front-end feeding mechanism (5) is located at the entrance of the continuous rolling mill (1). One side of it is a pneumatic feeding device (51), and the other side is a trolley frame. The trolley frame is equipped with a mandrel trolley (505). The pneumatic feeding device (51) includes an opening and closing horn mouth limiting device (501), a double horn mouth guide cylinder (502), a pneumatic feeding linear bearing device guide column (503), and a feeding cylinder (504). The trolley frame and the pneumatic feeding device (51) are each equipped with several transmission rollers (506). All the transmission rollers (506) form the receiving groove of the front-end feeding mechanism (5).

4. The equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill according to claim 1, characterized in that: The limiting mandrel mechanism (4) is a rear-mounted type, including a working frame, a hydraulic limiting device or a rack and pinion limiting device.

5. The equipment for producing stainless steel pipes using a rear-mounted limited-movement mandrel continuous rolling mill according to claim 1, characterized in that: The length of the mandrel used by the limiting mandrel mechanism (4) is 6-8 meters and the hardness of the mandrel is 45-55°.

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