Multi-combination roller system of metal tube bar skew rolling mill
By employing a multi-combination roll system in a metal tube skew rolling mill and utilizing adjustable driven rolls to form a closed throat, the problems of insufficient dimensional accuracy and microstructure in existing technologies have been solved, thus achieving high-quality metal tube production.
Patent Information
- Application Number
- CN202512044495.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-02-24
AI Technical Summary
Existing skew rolling mills for metal tubes have difficulty guaranteeing the dimensional accuracy and microstructure of the products during the production process, and also suffer from problems such as large axial force, triangular formation at the tube tail, poor guide plate constraint, and complex structure.
By employing a multi-combination roll system, adjustable driven rolls are set between the active rolls to form a relatively closed rolling throat. Combined with the active roll pressing device and the driven roll adjusting device, the workpiece is rolled and formed in a throat with better sealing.
It improves the microstructure and internal and external surface quality of metal tubes, reduces the contact friction between the rolled piece and the tool, and extends tool life. It is suitable for producing difficult-to-deform metal materials and large-diameter thin-walled metal tubes.
Smart Images
Figure CN121551393A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal rolling technology, and more particularly to a multi-combination roll system for a metal tube and bar skew rolling mill. Background Technology
[0002] Currently, the main types of skew rolling mills used for producing seamless metal tubes are three-roll skew rolling mills and two-roll skew rolling mills.
[0003] 1. Three-roll skew rolling mill A three-roll skew mill has three rolls arranged at 120° intervals and rotating in the same direction, forming the throat of the rolling pass. The axes of the three rolls are at a certain angle to the rolling line, and the rotation of the rolls drives the workpiece forward in a spiral. The roll gap of a three-roll skew mill is open. A three-roll skew mill can be used for piercing tube billets and for rolling and extending rough tubes. The characteristics of a three-roll skew mill are: the workpiece is subjected to compressive stress in three directions, resulting in good deformation, making it suitable for piercing and rolling extension of difficult-to-deform metallic materials.
[0004] The disadvantage is that the axial force during the rolling process is large, which easily forms a tube tail triangle, making it unsuitable for producing thin-walled tubes and small-diameter tubes.
[0005] 2. Two-roll skew rolling mill A two-roll skew mill has two rolls arranged 180° apart and rotating in the same direction. Since the two rolls cannot form a relatively closed rolling throat, a guide plate or guide disc is needed between them. The axes of the two rolls have a certain angle with the rolling line, and the rotation of the rolls drives the workpiece forward in a spiral. A two-roll skew mill can be used for piercing tube blanks, as well as for leveling and rolling out rough tubes. The characteristics of a two-roll skew mill are: the rolls are arranged in two directions, the equipment structure is simple, roll adjustment is convenient, and there is no limitation on the minimum workpiece diameter. Large-diameter rolls can be used to roll small-diameter tubes. Thin-walled tubes can be produced.
[0006] The existing technology has several drawbacks. Firstly, the guide plate provides poor constraint, affecting metal deformation and tube forming accuracy. Secondly, the guide plate's rotation direction is inconsistent with the roll rotation direction, causing interference with the workpiece's movement. Thirdly, the guide plate is large and complex, impacting mill operation and maintenance. Furthermore, the workpiece is subjected to biaxial alternating stress, and the metal flow between the rolls is unconstrained, making it unsuitable for producing metal tubes with poor plasticity, resulting in low product precision. Summary of the Invention
[0007] The purpose of this invention is to provide a multi-combination roll system for a metal tube and bar skew rolling mill, which solves the problem that conventional skew rolling mills cannot guarantee the dimensional accuracy and microstructure of products.
[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a multi-combination roll system for a metal tube and bar skew rolling mill, including a skew rolling mill stand, at least two active rolls disposed on the skew rolling mill stand, and driven rolls disposed between adjacent active rolls; wherein the multiple active rolls and the multiple driven rolls cooperate to form a rolling channel for processing metal tubes.
[0009] In this embodiment, the distance between the active roll and the rolling channel axis is adjusted by the active roll pressing device, and the distance between the driven roll and the rolling channel axis is adjusted by the driven roll adjusting device.
[0010] In this embodiment, the active roll is further connected to the active roll pressing device via an active roll stand. The active roll pressing device is mounted on the skew mill stand to drive the active roll to move radially along the rolling channel.
[0011] In this embodiment, the driven roll is further connected to the driven roll adjustment device via a driven roll bracket, the base of the driven roll adjustment device is connected to the skew mill stand, and the driven roll adjustment device drives the driven roll to move radially along the rolling channel.
[0012] Furthermore in this embodiment, at least one driven roll is provided between adjacent driving rolls, and the diameter of the driven roll is 50-200mm.
[0013] In this embodiment, the active roll pressing device includes a mounting base for connecting the skew mill stand, a roll support mounted on the mounting base via a movable connecting plate, and a roll mounted on the roll support. The movable connecting plate includes a fixed support plate disposed on the mounting base, a movable support plate connected to the fixed support plate by a connecting screw, and a lifting adjustment mechanism for adjusting the distance between the movable support plate and the fixed support plate; The lifting and adjusting mechanism is one of a hydraulic cylinder, an electric telescopic cylinder, and an adjusting rod.
[0014] This embodiment also discloses a magnesium alloy seamless tube rolling production process, using the aforementioned multi-roll skew rolling mill, and proceeding according to the following steps: Step 1) Machining of cast magnesium alloy tube blanks The cast magnesium alloy tube blank is placed on a machining tool, and the attachments and surface defects on the outer surface are removed by the machining tool. A hole is drilled in the center of the tube blank according to the process requirements. Step 2) Heating the cast magnesium alloy tube blank The processed tube blank is placed in a heating furnace and heated. The heating temperature is set to 450-550℃ according to the tube blank material. Step 3) Reducing the diameter of cast magnesium alloy tube blanks The processed cast magnesium alloy tube blank is subjected to a diameter reduction process through a multi-stand three-roll Y-type reducing mill. Step 4) Reheating The temperature of the rolled magnesium alloy tube blank was restored to 450-550℃ using an induction heating and temperature regulation furnace. Step 5) Perforation After reheating, the rolled magnesium alloy tube billet enters a multi-roll skew rolling mill for skew rolling and piercing to become a magnesium alloy rough tube. Step 6) Rolling and extending of magnesium alloy rough tubes Magnesium alloy rough tube (6) is inserted into an expandable and contractile oil-filled hot core rod. The length of the core rod is 150-250 mm longer than the length of the rough tube (6) after extension. Then it is rolled and extended into a hot-rolled magnesium alloy seamless tube by a multi-stand three-roll Y-type extension mill, and the wall thickness is reduced. Step 7) Hot-rolled magnesium alloy seamless tube warm drawing forming Hot-rolled magnesium alloy seamless tubes are fed into a 200KN hydraulic drawing machine for warm drawing and wall reduction forming, further reducing the wall thickness. Step 8) Removing rods and finishing After being drawn, the seamless magnesium alloy tube enters the mandrel release machine. The hydraulic oil inside the expandable and contractible oil-filled mandrel is depressurized, and the diameter of the mandrel shrinks. The hook of the mandrel release machine hooks the hook at the head of the mandrel, and the chain traction machine pulls the mandrel out. The seamless magnesium alloy tube enters the collection device and then enters the finishing process, where the head and tail are cut off, and it is processed into the final finished seamless magnesium alloy tube.
[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows: The multi-roll skew rolling mill used in this invention employs adjustable driven rolls positioned between the driving rolls, forming a relatively closed rolling throat with the driving rolls. Metal tubes can be rolled and formed in this better-sealed throat, resulting in products with good microstructure and high-quality internal and external surfaces. The multi-roll skew rolling mill of this invention features low contact friction between the workpiece and the tool, low tool wear, long tool life, and good material adaptability, making it suitable for producing seamless tubes from difficult-to-deform metal materials and large-diameter thin-walled metal tubes. Attached Figure Description
[0016] The invention will be further described below with reference to the accompanying drawings. Figure 1 A schematic diagram of the skew rolling mill stand of the multi-roll skew rolling piercing mill with an equilateral triangular arrangement according to the present invention; Figure 2 A schematic diagram of a skew mill stand for a multi-roll skew mill with an inverted triangular arrangement; Figure 3 A schematic diagram of a skew mill stand for a horizontally arranged two-roll skew mill; Figure 4A schematic diagram of a skew mill stand for a vertically arranged two-roll skew mill; Figure 5 This is a schematic diagram of an active roller pressing device.
[0017] Explanation of reference numerals in the attached drawings: 1-Slant mill stand; 2-Driven roll; 3-Driven roll pressing device; 4-Driven roll; 5-Driven roll adjusting device; 6-Raw tube; 7-Roll body; 8-Roll body support; 9-Movable connecting plate; 10-Mounting base; 11-Adjusting rod; 12-Locking nut; 13-Connecting screw; 14-Mounting hole with the mill stand; 15-Square head of the adjusting rod; 16-Nut seat. Detailed Implementation
[0018] This embodiment discloses a multi-combination roll system for a metal tube and bar skew rolling mill, including a skew mill stand 1, at least two active rolls 2 installed on the skew mill stand 1, and driven rolls 4 installed between adjacent active rolls 2; wherein the multiple active rolls 2 and the multiple driven rolls 4 cooperate to form a rolling channel (specifically a rolling throat) for processing metal tubes.
[0019] In this embodiment, the distance between the active roll 2 and the axial direction of the rolling channel is adjusted by an active roll reduction device, and the distance between the driven roll 4 and the axial direction of the rolling channel is adjusted by a driven roll adjustment device 5. The active roll 2 is connected to the active roll reduction device via an active roll stand, and the active roll reduction device is mounted on the skew mill stand 1 to drive the active roll 2 to move radially along the rolling channel.
[0020] refer to Figure 5 The active roller pressing device includes a mounting base 10 for connecting the frame, a roller support 8 disposed on the mounting base 10 via a movable connecting plate 9, and a roller 7 mounted on the roller support 8.
[0021] Specifically, the movable connecting plate 9 includes a fixed support plate mounted on the mounting base 10, a movable support plate connected to the fixed support plate via a connecting screw 13 and a locking nut 12, and a lifting adjustment mechanism for adjusting the distance between the movable support plate and the fixed support plate. In this embodiment, the lifting adjustment mechanism preferably has an adjusting rod 11, wherein the adjusting rod 11 is limited and set on the fixed support plate by a nut seat 16, and the bottom of the adjusting rod 11 is installed with the end of the adjusting rod 11 abutting against the adjusting rod square head 16 at the bottom of the movable support plate; In this embodiment, the driven roll 4 is connected to the driven roll adjustment device 5 via a driven roll stand. The driven roll adjustment device 5 is mounted on the skew mill stand 1 to drive the driven roll 4 to move radially along the rolling channel.
[0022] In this embodiment, one or two driven rolls 4 may be installed between adjacent driving rolls 2, and the diameter of the driven rolls 4 is 50 to 200 mm.
[0023] refer to Figure 3 and Figure 4 When there are two active rolls 2, the two active rolls 2 are symmetrically arranged on the skew mill stand 1, and two driven rolls 4 can be symmetrically installed on both sides between adjacent active rolls 2.
[0024] refer to Figure 1 and Figure 2 When the number of active rolls 2 is three, the three active rolls 2 are arranged in an equilateral or negative triangle on the skew mill stand 1.
[0025] The rolling system on the aforementioned multi-roll skew rolling mill can be applied to a multi-roll skew rolling piercing mill.
[0026] Application examples This embodiment discloses a magnesium alloy seamless tube rolling production process, which is carried out according to the following steps: Step 1) Machining of cast magnesium alloy tube blanks A cast magnesium alloy tube blank with a diameter of 300 mm and a length of 1200 mm is placed on a special machining tool. The attachments and surface defects on the outer surface are removed by the machining tool, and a hole with a diameter of less than 80 mm is drilled in the center of the tube blank according to the process requirements. Step 2) Heating the cast magnesium alloy tube blank The processed tube blank is placed in an electric heating furnace and heated. The heating temperature is set to 450-550℃ according to the material of the tube blank. Step 3) Reducing the diameter of cast magnesium alloy tube blanks A 300mm diameter cast magnesium alloy tube blank is reduced to 250mm using a 1650 three-roll Y-type reducing mill with five skew rolling mill stands. Step 4) Reheating The temperature of the rolled magnesium alloy tube blank was restored to 450-550℃ using an induction heating and temperature regulation furnace. Step 5) Perforation After reheating, the rolled magnesium alloy tube billet enters a multi-roll skew rolling mill for skew rolling and piercing to become magnesium alloy rough tube 6. The multi-roll skew rolling mill consists of two drive rolls and four driven rolls. The pierced rough tube 6 has a diameter of 375mm and a wall thickness of less than 25mm; Step 6) Rolling and extending of magnesium alloy rough tube 6 Magnesium alloy rough tube 6 is inserted into an expandable and contractile oil-filled hot mandrel. The length of the mandrel is 150-250mm longer than the length of the rough tube 6 after extension. Then it enters the 1650 three-roll Y-type extension mill of the five-slant rolling mill to be rolled and extended into a hot-rolled magnesium alloy seamless tube with a wall thickness reduced to 6.5mm. Step 7) Hot-rolled magnesium alloy seamless tube warm drawing forming Hot-rolled magnesium alloy seamless tubes are fed into a 200KN hydraulic drawing machine for warm drawing and wall reduction forming, reducing the wall thickness to 3.5mm; Step 8) Removing rods and finishing After being drawn, the seamless magnesium alloy tube enters the mandrel release machine. The hydraulic oil inside the expandable and contractile oil-filled mandrel is depressurized, causing the mandrel diameter to shrink. The hook of the release machine catches the hook at the head of the mandrel, and a chain traction machine pulls the mandrel out. The seamless magnesium alloy tube then enters a collection device and proceeds to the finishing process, where the ends are cut off, resulting in the final finished seamless magnesium alloy tube.
[0027] The multi-roll skew rolling mill in step 5) includes a skew rolling mill stand 1, a universal joint, a gearbox, a reducer, and a main motor. Its main structure is basically the same as that of existing multi-roll skew rolling mills, the difference being the structure of the skew rolling mill stand 1.
[0028] refer to Figures 1 to 4 The multi-roll skew rolling mill of the present invention has multiple active rolls 2 installed on the skew rolling mill stand 1. A passive roll pressing device adjusts the position of the active rolls 2. A driven roll 4 is installed between adjacent active rolls 2. The active rolls 2 and the driven rolls 4 together form the rolling throat. The driven roll 4 includes a driven roll frame, and a driven roll is installed inside the driven roll frame. A driven roll adjusting device 5 is fixedly installed on the outside of the driven roll frame. The driven roll moves radially along the rolling throat under the drive of the driven roll adjusting device 5. The diameter of the driven roll 4 is 50-200mm.
[0029] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A multi-combination roll system for a skew rolling mill for metal tubes and bars, characterized in that: It includes a skew mill stand (1), at least two active rolls (2) disposed on the skew mill stand (1), and driven rolls (4) disposed between adjacent active rolls (2). The plurality of active rolls (2) and the plurality of driven rolls (4) cooperate to form a rolling channel for processing metal tubes.
2. The multi-combination roll system of the skew rolling mill for metal tubes and bars according to claim 1, characterized in that: The active roll (2) is adjusted to have a distance from the axis of the rolling channel by an active roll pressing device, and the driven roll (4) is adjusted to have a distance from the axis of the rolling channel by a driven roll adjusting device (5).
3. The multi-combination roll system of the skew rolling mill for metal tubes and bars according to claim 2, characterized in that: The active roll (2) is connected to the active roll pressing device via the active roll stand. The active roll pressing device is set on the skew mill stand (1) to drive the active roll (2) to move radially along the rolling channel.
4. The multi-combination roll system of the skew rolling mill for metal tubes and bars according to claim 2, characterized in that: The driven roll (4) is connected to the driven roll adjustment device (5) via the driven roll bracket. The base of the driven roll adjustment device (5) is connected to the skew mill stand (1). The driven roll adjustment device (5) drives the driven roll (4) to move radially along the rolling channel.
5. The multi-combination roll system of the skew rolling mill for metal tubes and bars according to claim 1, characterized in that: At least one driven roll (4) is provided between adjacent active rolls (2), and the diameter of the driven roll (4) is 50 to 200 mm.
6. The multi-combination roll system of the skew rolling mill for metal tubes and bars according to claim 2, characterized in that: The active roll pressing device includes a mounting base (10) for connecting the skew mill stand (1), a roll support (8) disposed on the mounting base (10) via a movable connecting plate (9), and a roll (7) disposed on the roll support (8). The movable connecting plate (9) includes a fixed support plate disposed on the mounting base (10), a movable support plate connected to the fixed support plate by a connecting screw (13), and a lifting adjustment mechanism for adjusting the distance between the movable support plate and the fixed support plate. The lifting and adjusting mechanism is one of a hydraulic cylinder, an electric telescopic cylinder, and an adjusting rod.