Method for preventing guide disc from sticking steel when CrMo alloy steel is rolled by pipe mill

Abstract

The invention provides a method for preventing steel adhesion to a guide disc when a pipe mill rolls CrMo alloy steel, which comprises the following steps of: before rolling the CrMo alloy steel, rolling common carbon manganese steel or low alloy steel, and starting cooling water to cool the guide disc during the rolling time, so that the guide disc is in a chilling and heating state, and hardening the working surface of the guide disc; and after the working surface is quenched to form a ferroferric oxide oxidation film, rolling the CrMo alloy steel by using a guide disc. And the ferroferric oxide oxidation film can effectively prevent a rolled piece from being adhered to the working surface of the guide disc during rolling, so that the occurrence frequency of the problem of adhering steel to the guide disc is reduced. According to the method for preventing the guide disc from being bonded with the steel when the pipe mill rolls the CrMo alloy steel, the method can be implemented without greatly changing equipment, operation is easy, the application range is wide, the problem that the guide disc is bonded with the steel when the pipe mill rolls the CrMo alloy steel can be effectively solved, and the service life of the pipe mill is prolonged. And positive significance is achieved in the aspects of improving the product quality, reducing the rolling cost, improving the production efficiency and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-rolled seamless pipe equipment, and in particular relates to a method for preventing a guide disc from sticking to steel when a pipe rolling mill rolls CrMo alloy steel. Background Art

[0002] The guide plate is one of the important parts of the tube rolling mill. Its function is to form a deformation zone together with the rollers during hot rolling of seamless tubes, guide the tube body and apply radial compression deformation force to the tube body. In the Accu Roll tube rolling mill, two rollers arranged horizontally on the left and right, two guide plates arranged vertically on the top and bottom, and a mandrel coinciding with the rolling center line are used to form a closed pass for rolling tubes.

[0003] Accu Roll is a precision inclined tube rolling mill. Its process technology is becoming more and more mature and has become one of the main models of choice for steel tube manufacturers. In the existing technology, when Accu Roll tube rolling mills produce high-alloy steel tube products, especially when producing L80-3Cr steel grade tube products in API 5CT standard, a large amount of alloy elements are added to the steel billet, among which the Cr content is 2.8% to 3.2% and the Mo content is 0.3% to 0.5%. In addition, since the Accu Roll tube rolling mill adopts a production process with an active rotating large guide disc, it has the characteristics of large rolling deformation and high deformation rate, so that the rolled piece will produce temperature rise due to deformation heat. When the high-temperature rolled piece is rolled by the tube rolling mill, it will adhere to the surface of the guide disc to form sticky steel. After the sticky steel point increases and the surface strength increases after quenching, it will scratch the surface of the subsequent rolled rough pipe to form scratch defects. Moreover, since the steel sticking points are made of a different material from the guide disc matrix and have low bonding strength, they will fall off the guide disc under the rolling force and be pressed into the surface of the rough pipe during subsequent rolling to form rolling scar defects. After the seamless pipes with scratches or rolling scar defects are repaired, a large amount of waste will be generated because the wall thickness does not meet the API quality judgment standards.

[0004] In the prior art, in order to solve the above technical problems, online grinding of guide discs and frequent replacement of guide discs are adopted, which not only cannot solve the problem of guide disc sticking to steel from the root, but also increase a lot of downtime waiting time, increase guide disc consumption, and increase enterprise production costs. Summary of the invention

[0005] The embodiment of the present invention provides a method for preventing the guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel, aiming to solve the problem that the existing technology adopts the method of online grinding of the guide plate and frequent replacement of the guide plate to solve the problem of guide plate sticking to steel, which not only fails to solve the problem of guide plate sticking to steel from the root, but also increases a lot of downtime waiting time, increases guide plate consumption, and increases the production cost of the enterprise.

[0006] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for preventing the guide disc from sticking to the steel when the tube mill rolls CrMo alloy steel, comprising the following steps: Install the guide plate on the tube rolling mill, and first roll ordinary carbon manganese steel or low alloy steel before rolling CrMo alloy steel; When rolling ordinary carbon manganese steel or low alloy steel, the cooling water is intermittently turned on to cool the guide plate, so that the guide plate is in a state of rapid cooling and rapid heating, and the working surface of the guide plate is hardened; After the working surface of the guide disc is hardened to form a ferroferric oxide film, the guide disc is used to roll the CrMo alloy steel.

[0007] In a possible implementation, the method provided by the present invention for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill further comprises the following steps before rolling ordinary carbon manganese steel or low alloy steel: The working surface of the guide plate is obtained by machining according to the dimensions of the drawing, and after the machining is completed, the knife marks on the working surface of the guide plate are polished.

[0008] In a possible implementation, the present invention provides a method for preventing a guide disc from sticking to steel when a tube rolling mill rolls CrMo alloy steel. In the step of obtaining the working surface of the guide disc by processing according to the dimensions on the drawing, the working surface curve of the guide disc is formed by a first arc segment with a radius of R1 and a second arc segment with a radius of R2. The first arc segment is tangent to the second arc segment at a connection position, and the sum of the width L1 of the first arc segment and the width L2 of the second arc segment is the width L of the guide disc.

[0009] In a possible implementation, the present invention provides a method for preventing the guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel, wherein the width L1 of the first arc segment is greater than the width L2 of the second arc segment, and the diameter R1 of the first arc segment is smaller than the diameter R2 of the second arc segment.

[0010] In a possible implementation, the present invention provides a method for preventing a guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel, wherein the center of the first arc segment and the center of the second arc segment are located in the same vertical plane.

[0011] In a possible implementation, the present invention provides a method for preventing the guide plate from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. In the step of rolling the CrMo alloy steel, the Cr element content in the alloy steel is 2.8% to 3.2%, and the Mo element content is 0.3% to 0.5%.

[0012] In a possible implementation, the present invention provides a method for preventing a guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the ratio of the rotation speed of the guide plate to the rotation speed of the roller is 2:1.

[0013] In one possible implementation, the present invention provides a method for preventing guide discs from sticking to steel when a tube rolling mill is rolling CrMo alloy steel. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the ratio of the spacing between two guide discs arranged opposite to each other up and down to the spacing between two rollers arranged opposite to each other left and right, that is, the hole ovality coefficient, is 1.08.

[0014] In a possible implementation, the present invention provides a method for preventing the guide plate from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the feed angle of the roller is 7°.

[0015] In a possible implementation, the present invention provides a method for preventing the guide plate from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. In the step of rolling CrMo, the round billet of the CrMo alloy steel is heated and punched in an annular furnace to form a rough tube. The wall thickness of the rough tube is 4 to 7 mm greater than the wall thickness of the rough tube after rolling, and the outer diameter of the rough tube is the same as the outer diameter of the rough tube after rolling or the difference is ≥6 mm.

[0016] Compared with the prior art, the method provided by the present invention for preventing the guide disc from sticking to the steel when the tube mill rolls CrMo alloy steel has the following beneficial effects: The present invention provides a method for preventing the guide disc from sticking to steel when a tube mill rolls CrMo alloy steel. Before rolling the CrMo alloy steel, ordinary carbon manganese steel or low alloy steel is first rolled. When rolling the ordinary carbon manganese steel or low alloy steel, cooling water is intermittently turned on to cool the guide disc, so that the guide disc is in a state of rapid cooling and heating, and the working surface of the guide disc is hardened; after the working surface of the guide disc is hardened to form a ferroferric oxide film, the guide disc is used to roll the CrMo alloy steel. Since the working surface of the guide disc has a dense and smooth ferroferric oxide film, the adsorption force of the ferroferric oxide film on the surface of the rolled piece is smaller than that of the rolled piece matrix, so the problem of the rolled piece sticking to the working surface of the guide disc during rolling can be effectively blocked, thereby reducing the frequency of the problem of the guide disc sticking to steel.

[0017] From the perspective of operational convenience, the method provided by the present invention for preventing the guide plate from sticking to steel when a tube mill rolls CrMo alloy steel can be implemented without major changes to the equipment, is simple to operate, and has a wide range of applications. From the perspective of improving product quality, the present invention can effectively eliminate the problem of the guide plate sticking to steel when a tube mill rolls CrMo alloy steel, and has positive significance in improving product quality, reducing rolling costs, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A dimensional parameter diagram of a guide plate in a method for preventing a guide plate from sticking to steel when a tube mill rolls CrMo alloy steel provided by the present invention; Figure 2 For Figure 1 The guide disc dimension parameter table corresponding to the guide disc dimension parameter diagram; Figure 3 A step diagram of a method provided by the present invention for preventing the guide disc from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] Please also read Figures 1 to 3 The following describes a method for preventing the guide disc from sticking to steel when a tube rolling mill rolls CrMo alloy steel, provided by an embodiment of the present invention.

[0021] See also Figure 3 In order to solve the problem that the existing technology adopts the method of online grinding of the guide plate and frequent replacement of the guide plate for the guide plate sticking to the steel, which not only fails to solve the problem of the guide plate sticking to the steel from the root, but also increases a large amount of downtime waiting time, increases the consumption of the guide plate, and increases the production cost of the enterprise, the embodiment of the present invention provides a method for preventing the guide plate from sticking to the steel when the tube mill rolls CrMo alloy steel, comprising the following steps: (1) Install the guide plate on the tube rolling mill. Before rolling the CrMo alloy steel, first roll ordinary carbon manganese steel or low alloy steel; (2) When rolling ordinary carbon manganese steel or low alloy steel, intermittently open the cooling water to cool the guide plate, so that the guide plate is in a state of rapid cooling and rapid heating, and the working surface of the guide plate is hardened; (3) After the working surface of the guide plate is hardened to form a dense and smooth ferroferric oxide film, the guide plate is used to roll the CrMo alloy steel.

[0022] Compared with the prior art, the method for preventing the guide disc from sticking to the steel when the tube mill rolls CrMo alloy steel provided by the embodiment of the present invention has the following beneficial effects: The method provided by the embodiment of the present invention is to prevent the guide disc from sticking to steel when the tube mill rolls CrMo alloy steel. Before rolling the CrMo alloy steel, ordinary carbon manganese steel or low alloy steel is first rolled. When rolling the ordinary carbon manganese steel or low alloy steel, the cooling water is intermittently turned on to cool the guide disc, so that the guide disc is in a state of rapid cooling and heating, and the working surface of the guide disc is hardened; after the working surface of the guide disc is hardened to form a ferroferric oxide film, the guide disc is used to roll the CrMo alloy steel. Since the working surface of the guide disc has a dense and smooth ferroferric oxide film, the adsorption force of the ferroferric oxide film on the surface of the rolled piece is smaller than that of the rolled piece matrix, so it can effectively prevent the problem of the rolled piece sticking to the working surface of the guide disc during rolling, thereby reducing the frequency of the problem of the guide disc sticking to steel.

[0023] From the perspective of operational convenience, the method for preventing the guide plate from sticking to steel when a tube mill rolls CrMo alloy steel provided by the embodiment of the present invention can be implemented without major changes to the equipment, is simple to operate, and has a wide range of applications. From the perspective of improving product quality, the embodiment of the present invention can effectively eliminate the problem of the guide plate sticking to steel when a tube mill rolls CrMo alloy steel, and has positive significance in improving product quality, reducing rolling costs, and improving production efficiency.

[0024] The method for preventing the guide plate from sticking to steel when the tube mill rolls CrMo alloy steel provided in the embodiment of the present invention can be applied to the existing Accu Roll tube mill unit or other tube mill units, and can increase the service life of the guide plate, reduce the replacement frequency, and improve the surface quality of the product. It can be used for pipes such as oil casing, pipeline pipe, structural pipe, fluid pipe, boiler pipe, etc.

[0025] The guide plate is an essential tool and die in the production process of hot-rolled seamless steel pipes in precision tube mills. It works simultaneously with the rollers to complete the deformation of seamless steel pipes in this process. The working surface of the guide plate is in direct contact with the high-temperature rolled piece, and the working environment is a high-temperature environment (temperature is about 1100℃), and it will be subjected to rolling and sliding friction under the action of compressive stress. The working environment is harsh and the consumption is large.

[0026] In order to improve the service life of the guide disc, the embodiment of the present invention firstly rolls the guide disc with ordinary carbon manganese steel or low alloy steel before rolling the CrMo alloy steel. During the rolling, the guide disc's own cooling system or an external cooling system can be used to intermittently cool the working surface of the guide disc, so that the working surface of the guide disc is repeatedly changed between high temperature and low temperature to achieve the effect of hardening, and finally form a dense and smooth ferroferric oxide film on the working surface. The ferroferric oxide film has the characteristics of high hardness and smooth surface. Compared with the material of the guide disc itself, it has stronger resistance to the invasion of iron oxide scale on the surface of the high-temperature tube blank, which not only improves the service life of the guide disc, but also is not easy to adhere to the surface of the rolled piece, greatly reducing the occurrence of the problem of sticking.

[0027] Specifically, when cooling the guide disc, it can be achieved by setting a plurality of cooling nozzles on one side of the guide disc, and the cooling nozzles are used to spray water or coolant, and the plurality of cooling nozzles can be connected to the cooling water pumping assembly through a cooling water pipe. During the production process, the number of cooling nozzles and the water spray flow rate can be controlled according to the guide disc size, feeding speed, temperature and other parameters to achieve a suitable cooling effect. Specifically, a one-to-one corresponding valve can be set for each cooling nozzle, and the opening of the cooling nozzle and the water spray flow rate can be regulated by adjusting the opening of the control valve. The valve can specifically be a manual switching valve such as a ball valve, or an automatic valve such as a solenoid valve. When cooling the guide disc, the cooling water should be able to completely cover the working surface of the guide disc to ensure the cooling effect.

[0028] During actual production, personnel should be arranged to patrol the production line to check the cooling effect of the guide plate, and ensure that the surface of the guide plate is fully cooled while preventing excessive splashing of cooling water from the guide plate onto the capillary tube, causing the capillary tube temperature to drop too quickly.

[0029] It can be understood that the method provided by the present invention for preventing the guide plate from sticking to steel when the tube rolling mill rolls CrMo alloy steel can be directly modified and implemented on the tube rolling mill unit in the prior art, without specific restrictions on the size of the guide plate, the temperature of the rolled tube, the feeding speed, etc., and the user can choose according to the actual situation.

[0030] See also Figure 1 and Figure 2 In some possible embodiments, a method for preventing a guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel is provided in an embodiment of the present invention. Before the tube rolling mill rolls ordinary carbon manganese steel or low alloy steel, the method further includes the following steps: processing the working surface of the guide plate according to the dimensions of the drawing, and after the processing is completed, grinding the knife marks on the working surface of the guide plate.

[0031] The specific size parameters of the guide plate in the embodiment of the present invention can be referred to Figure 1 and Figure 2 The working surface of the guide plate can be processed by a processing machine tool.

[0032] See also Figure 1 and Figure 2 In some possible embodiments, an embodiment of the present invention provides a method for preventing a guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel. In the step of obtaining a working surface of the guide plate by machining according to the dimensions of the drawing, a working surface curve of the guide plate is formed by a first arc segment with a radius of R1 and a second arc segment with a radius of R2. The first arc segment is tangent to the second arc segment at a connection position. The sum of a width L1 of the first arc segment and a width L2 of the second arc segment is a width L of the guide plate.

[0033] like Figure 1 and Figure 2As shown, this embodiment designs an Accu Roll tube rolling mill guide disc working surface curve, and divides the curve of the guide disc working surface cross section into two sections, namely L1 and L2, and the two sections L1 and L2 are designed to be arc-shaped, and the corresponding arc diameters are R1 and R2, respectively. It has the characteristics of making the guide disc working surface evenly stressed, has high wrapping properties for the rolled piece, and is more in line with the morphology of the rolled piece during rolling, thereby reducing the occurrence of the problem of concentrated stress on the guide disc working surface and steel sticking.

[0034] See also Figure 1 and Figure 2 In some possible embodiments, the present invention provides a method for preventing the guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel, wherein the width L1 of the first arc segment is greater than the width L2 of the second arc segment, and the diameter R1 of the first arc segment is less than the diameter R2 of the second arc segment.

[0035] See also Figure 1 and Figure 2 In some possible embodiments, the present invention provides a method for preventing a guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel, wherein the center of the first arc segment and the center of the second arc segment are located in the same vertical plane.

[0036] Specifically, Figure 2 Three sizes of guide plates are provided, namely 150mm, 200mm and 220mm in width. When the width is 150mm, the L1 size corresponding to the guide plate working surface curve is 85mm, the L2 size is 65mm, the R1 size is 95mm, the R2 size is 180mm, and the R3 size is 1.5mm. When the width is 200mm, the L1 size corresponding to the guide plate working surface curve is 113mm, the L2 size is 87mm, the R1 size is 119mm, the R2 size is 250mm, and the R3 size is 1.5mm. When the width is 220mm, the L1 size corresponding to the guide plate working surface curve is 118mm, the L2 size is 102mm, the R1 size is 130mm, the R2 size is 290mm, and the R3 size is 2mm. The fillet size on the other side opposite to R3 can be 10mm.

[0037] In some possible embodiments, the present invention provides a method for preventing the guide plate from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. In the step of rolling the CrMo alloy steel, the Cr element content in the alloy steel is 2.8% to 3.2%, and the Mo element content is 0.3% to 0.5%.

[0038] In some possible embodiments, the present invention provides a method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube mill. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the rotation speed of the guide disc and the rotation speed of the roller can be adjusted according to the type and specification of the rolled steel. In a specific embodiment, the ratio of the rotation speed of the guide disc to the rotation speed of the roller is 2:1.

[0039] In some possible embodiments, the present invention provides a method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube mill. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the ratio of the distance between the two guide discs arranged opposite to each other up and down to the distance between the two rollers arranged opposite to each other left and right is 1.08. The ratio of the distance between the guide discs to the distance between the rollers determines the ovality of the rolled piece in the deformation zone. During the production process, the ovality of the pass should be reasonably controlled to avoid the guide disc sticking to the steel due to too small ovality and difficulty in rotating the tube blank.

[0040] In some possible embodiments, the present invention provides a method for preventing the guide plate from sticking to steel when a tube rolling mill rolls CrMo alloy steel. When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the feed angle of the roller is 5-8°.

[0041] Reasonable setting of the tube feeding angle has a significant impact on the tube rolling process. The impact of the feeding angle is mainly reflected in the three aspects of affecting the movement of the rolled piece, affecting the product quality and production efficiency. The selection of the feeding angle has an important influence on the dimensional accuracy and surface quality of the product. The size of the feeding angle directly affects the movement trajectory and speed of the rolled piece between the rollers. The appropriate feeding angle can ensure that the rolled piece enters the roller smoothly, avoiding jamming or deviation caused by improper angles, thereby affecting production efficiency and product quality.

[0042] In the actual production process, a feed angle that is too large may cause uneven deformation of the rolled piece and produce ovality problems, while a feed angle that is too small may make it difficult for the rolled piece to pass through the rollers smoothly, affecting the roundness and dimensional consistency of the product. In addition, a reasonable feed angle design can also reduce resistance during the rolling process, reduce energy consumption, and improve production efficiency. An unreasonable feed angle design will increase energy consumption and even cause equipment failure, affecting production progress. In this embodiment, the feed angle of the roller is 5-8°, specifically 7°.

[0043] In some possible embodiments, the present invention provides a method for preventing the guide plate from sticking to the steel when a tube rolling mill rolls CrMo alloy steel. In the step of rolling the CrMo alloy steel, the round billet of the CrMo alloy steel is heated and punched in an annular furnace to form a rough tube. The wall thickness of the rough tube is 4 to 7 mm greater than the wall thickness of the rough tube after rolling, and the outer diameter of the rough tube is the same as the outer diameter of the rough tube after rolling or the difference is ≥ 6 mm.

[0044] In this embodiment, the steel billet is heated in a ring furnace. During the heating period, it should be avoided that the heating temperature of the tube billet in the ring heating furnace exceeds the heating temperature set for the steel type or the furnace time exceeds the time required by the heating system of the steel type, so as to avoid the steel billet temperature being too high, the internal energy being too high, and the rough tube sticking to the guide plate during the punching process.

[0045] It can be understood that the various parts in the above-mentioned embodiments can be freely combined or deleted to form different combination embodiments. The specific contents of each combination embodiment will not be repeated here. After this description, it can be considered that the specification of the present invention has recorded various combination embodiments and can support different combination embodiments.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preventing the guide plate from sticking to the steel when rolling CrMo alloy steel in a tube mill, characterized in that: The following steps are involved: Install the guide plate on the tube rolling mill, and first roll ordinary carbon manganese steel or low alloy steel before rolling CrMo alloy steel; When rolling ordinary carbon manganese steel or low alloy steel, the cooling water is intermittently turned on to cool the guide plate, so that the guide plate is in a state of rapid cooling and rapid heating, and the working surface of the guide plate is hardened; After the working surface of the guide disc is hardened to form a ferroferric oxide film, the guide disc is used to roll the CrMo alloy steel.

2. The method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: Before rolling ordinary carbon manganese steel or low alloy steel, the following steps are also included: The working surface of the guide plate is obtained by machining according to the dimensions of the drawing, and after the machining is completed, the knife marks on the working surface of the guide plate are polished.

3. The method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 2, characterized in that: In the step of obtaining the working surface of the guide disk according to the dimensions of the drawing, the working surface curve of the guide disk is formed by a first arc segment with a radius of R1 and a second arc segment with a radius of R2, the first arc segment is tangent to the second arc segment at a connecting position, and the sum of the width L1 of the first arc segment and the width L2 of the second arc segment is the width L of the guide disk.

4. A method for preventing the guide disc from sticking to steel when rolling CrMo alloy steel in a tube rolling mill according to claim 3, characterized in that: The width L1 of the first arc segment is greater than the width L2 of the second arc segment, and the diameter R1 of the first arc segment is smaller than the diameter R2 of the second arc segment.

5. A method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 4, characterized in that: The center of the first arc segment and the center of the second arc segment are located in the same vertical plane.

6. The method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: In the step of rolling the CrMo alloy steel, the Cr element content in the alloy steel is 2.8% to 3.2%, and the Mo element content is 0.3% to 0.5%.

7. The method for preventing the guide plate from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the ratio of the rotation speed of the guide plate to the rotation speed of the roller is 2:

1.

8. The method for preventing the guide disc from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the ratio of the distance between the two guide plates arranged opposite to each other up and down to the distance between the two rollers arranged opposite to each other left and right is 1.

08.

9. The method for preventing the guide plate from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: When rolling CrMo alloy steel, ordinary carbon manganese steel or low alloy steel, the feed angle of the roll is 5-8°.

10. The method for preventing the guide plate from sticking to the steel when rolling CrMo alloy steel in a tube rolling mill according to claim 1, characterized in that: In the step of rolling CrMo alloy steel, the round billet of CrMo alloy steel is heated and punched in a ring furnace to form a rough pipe, the wall thickness of the rough pipe is 4 to 7 mm greater than the wall thickness of the rough pipe after rolling, and the outer diameter of the rough pipe is the same as the outer diameter of the rough pipe after rolling or the difference is ≥6 mm.

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