Section steel rolling method

Abstract

The invention relates to a profile steel rolling method which comprises the following steps: carrying out at least one high-pressure water descaling treatment on a steel billet by using a primary high-pressure water descaling system, and controlling the pressure of the high-pressure water descaling system to be greater than or equal to 15Mpa in the high-pressure water descaling treatment process; continuously rolling the treated steel billet by using a roughing mill unit to obtain a roughing rolled piece; cutting off a tongue-shaped defect formed at the end part of the rolled piece in the extending direction by utilizing a head-cutting flying shear; and continuously rolling the rough rolled piece with the tongue-shaped defect removed by using a finishing mill group to obtain the profile steel. Compared with the prior art, high-performance, high-efficiency, high-quality and low-cost production of small and medium-sized section steel can be realized; the high-pressure water descaling system can effectively remove primary oxide scale generated by heating and secondary oxide scale generated in the rolling process, and the product quality is improved; the two processes of controlled rolling in the finish rolling process and controlled cooling after finish rolling are respectively used or used in an overlapped mode, and the product strength is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot rolling technology, and in particular relates to a steel section rolling method. Background Art

[0002] Hot-rolled steel mainly includes: H-shaped steel, angle steel, channel steel, I-shaped steel, as well as special-shaped steel such as rails, mining U-shaped steel, track steel, elevator guide rails, etc. Among them, small and medium-sized H-shaped steel, angle steel, channel steel, I-shaped steel, etc. have relatively simple cross-sections, and the full continuous rolling scheme has matured. Most of the other complex cross-section special-shaped steels adopt full headless rolling or semi-continuous rolling. However, with the innovation of special-shaped steel hole design and the improvement of automation control level, the rolling of some complex cross-section special-shaped steels is also developing towards the full continuous rolling direction with higher production efficiency of the production process.

[0003] Green and low-carbon transformation is an inevitable trend in the development of the steel industry. Hot-rolled steel is widely used in various industries such as construction, infrastructure, iron towers, vehicle and ship manufacturing, high-speed rail, cofferdams, etc. The high quality and lightweight of the end products are the inevitable requirements for the development of the industry. The common key manufacturing technologies of high-quality steel include advanced material design technology, smelting technology, rolling technology, quality stabilization technology, welding technology, etc. High strength is one of the important indicators of high quality. The development of high-strength steel rolling technology is relatively backward. At present, the main applications are online waste heat heat treatment of rails and ultra-fast cooling technology after rolling of angle steel and steel. A systematic rolling process that can be widely used in hot-rolled steel to improve product strength needs to be proposed. Summary of the invention

[0004] In order to solve all or part of the above problems, the present invention aims to provide a steel section rolling method. The steel section obtained by the steel section rolling method of the present invention has higher quality.

[0005] According to one aspect of the present invention, a method for rolling a section steel is provided, the method comprising:

[0006] The steel billet is subjected to at least one high-pressure water descaling treatment using a primary high-pressure water descaling system, and the pressure of the high-pressure water descaling system is controlled to be ≥15Mpa during the high-pressure water descaling treatment process;

[0007] The treated steel billet is continuously rolled by a rough rolling mill to obtain a rough rolled product;

[0008] Use the flying shear to remove the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction;

[0009] The rough rolled piece from which the "tongue-shaped" defect has been removed is continuously rolled by a finishing mill to obtain the steel section.

[0010] Furthermore, the steel billet is subjected to at least one high-pressure water descaling treatment using a high-pressure water descaling system, and the pressure of the high-pressure water descaling system is controlled to be ≥15Mpa during the high-pressure water descaling treatment process as follows:

[0011] The steel billet is descaled by high pressure water at least once using a high pressure water descaling system, and the descaling working pressure is ≥20Mpa; if the steel billet is descaled by high pressure water multiple times, the minimum working pressure of the control system is ≥15Mpa.

[0012] Furthermore, in the continuous rolling of the processed steel billet by the roughing mill, the number of the roughing mills used is ≥5.

[0013] Furthermore, after the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction is removed by the head-cutting flying shear, the method further comprises:

[0014] The rough rolled piece from which the "tongue-shaped" defect has been removed is cooled by a water cooling device, and the amount and pressure of cooling water used in the cooling process are determined according to the inlet temperature of the rough rolled piece entering the water cooling device and the outlet temperature requirement;

[0015] The method of continuously rolling the rough rolled piece from which the "tongue-shaped" defect has been removed by using the finishing mill group specifically includes: continuously rolling the rough rolled piece that has been cooled by using the finishing mill group.

[0016] Furthermore, the finishing mill is used to continuously roll the rough rolled piece from which the "tongue-shaped" defect has been removed to obtain the steel section:

[0017] The rolling temperature of the finishing rolling process is controlled to be 850°C to 950°C, and the deformation rate of the finishing rolling process is controlled to be greater than 50%. The rough-rolled piece with the "tongue-shaped" defect removed is continuously rolled using a finishing rolling unit to obtain the steel section.

[0018] Furthermore, in the continuous rolling of the rough-rolled workpiece from which the "tongue-shaped" defect has been removed by using the finishing mill, the number of the finishing mills used is ≥ 7, and the first number of the finishing mills is a horizontal rolling mill.

[0019] Furthermore, at least one secondary high-pressure water descaling system is provided between the seven finishing mills;

[0020] The method of continuously rolling the rough-rolled workpiece with the "tongue-shaped" defect removed by using the finishing mill is specifically as follows: continuously rolling the rough-rolled workpiece with the "tongue-shaped" defect removed by using the finishing mill, and when the rolled workpiece passes through the secondary high-pressure water descaling system, the workpiece is descaled by high-pressure water using the secondary high-pressure water descaling system, and the working pressure of the high-pressure water descaling system is ≥15Mpa.

[0021] Furthermore, the method of continuously rolling the rough rolled piece from which the "tongue-shaped" defect has been removed by a finishing mill to obtain the steel section further comprises:

[0022] The rough rolled piece from which the "tongue-shaped" defect has been removed is continuously rolled by a finishing mill to obtain a finished rolled piece;

[0023] The finished rolled piece is cooled, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section.

[0024] Furthermore, the finished rolled piece is subjected to cooling treatment, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section specifically as follows:

[0025] The finished rolled piece is cooled by a pulse cooling method that alternates between water cooling and air cooling, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section.

[0026] Furthermore, after the finished rolled piece is cooled and the cooling rate of the finished rolled piece is controlled to be ≥1°C / s when the temperature of the finished rolled piece is greater than 720°C, and the cooling rate of the finished rolled piece is controlled to be <1°C / s when the temperature of the finished rolled piece is less than 720°C, to obtain the steel section, the method also includes: processing the steel section using a flying shear or a hot saw and sending the processed steel section to a cooling bed for cooling.

[0027] It can be seen from the above technical solution that the steel section rolling method provided by the present invention has the following beneficial effects:

[0028] Compared with the prior art, the present invention can achieve high-performance, high-efficiency, high-quality and low-cost production of small and medium-sized steel sections; the high-pressure water descaling system of the present invention can effectively remove the primary iron oxide scale generated by heating and the secondary iron oxide scale generated in the rolling process, thereby improving product quality; the two processes of controlled rolling in the finishing process or controlled cooling after finishing rolling are used separately or in a superimposed manner, thereby improving product strength; in addition, for special-shaped materials, with the innovative hole system design, a full continuous rolling process is realized, which can also improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an equipment diagram corresponding to the steel section rolling process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to better understand the purpose, structure and function of the present invention, a steel section rolling method of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0031] The high-quality steel section rolling process of the embodiment of the present invention includes: high-pressure water descaling, continuous rolling in a roughing mill, head cutting, continuous rolling in a finishing mill, shearing to size, controlled rolling, and controlled cooling after rolling.

[0032] Specifically, it shows a steel section rolling method according to an embodiment of the present invention, comprising the following steps:

[0033] Step S01: perform at least one high-pressure water descaling treatment on the steel billet using a high-pressure water descaling system, and during the high-pressure water descaling treatment, control the pressure of the high-pressure water descaling system to be ≥15Mpa.

[0034] In step S01, the steel billet is subjected to at least one high-pressure water descaling treatment using a one-time high-pressure water descaling system. During the high-pressure water descaling treatment, the pressure of the high-pressure water descaling system is controlled to be ≥15Mpa. Specifically, the steel billet is subjected to at least one high-pressure water descaling treatment using a one-time high-pressure water descaling system, and the descaling working pressure is ≥20Mpa; if the steel billet is subjected to multiple high-pressure water descaling treatments, the minimum working pressure of the control system is controlled to be ≥15Mpa.

[0035] The primary high-pressure water descaling system of this embodiment can effectively remove the primary iron oxide scale generated by heating and the secondary iron oxide scale generated during the rolling process, thereby improving product quality.

[0036] Step S02: Continuously rolling the processed steel billet using a rough rolling mill to obtain a rough rolled product.

[0037] Specifically, the steel billet that meets the rolling requirements is descaled by a high-pressure water descaling device and then enters the roughing mill for rolling. The roughing mill is usually composed of two forms: a horizontal rolling mill and a vertical rolling mill. The positions and numbers of the horizontal roughing mill and the vertical roughing mill are determined by the hole system of the rolled product. The billet is rolled into the required intermediate section in the roughing mill according to the rolling procedure of the product.

[0038] Wherein, in step S02, when the processed steel billet is continuously rolled by the roughing mill, the number of the roughing mills used is ≥5.

[0039] Step S03: using a head-cutting flying shear to remove the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction.

[0040] The purpose of using the cutting head flying shear to cut off the enlarged or split "tongue-shaped" defects in this embodiment is to prevent the existence of "tongue-shaped" defects from causing accidents during subsequent rolling. "Tongue-shaped" defects refer to the uneven flow of metal layers along the cross-section height of the rolled piece during the deformation process, resulting in a tongue-shaped defect at the end of the rolled piece in the extension direction.

[0041] Step S04: Continuously rolling the rough rolled piece from which the “tongue-shaped” defect has been removed using a finishing mill to obtain the required high-quality steel sections.

[0042] Specifically, the rough-rolled workpiece that meets the rolling temperature requirements enters the finishing mill for rolling; the finishing mill is configured with the number and form of rolling mills according to the product shape; the machine types used are usually composed of horizontal rolling mills, vertical rolling mills, universal rolling mills, two-roll / universal convertible rolling mills, etc.; in order to enable the finishing mill to better bite into the rough-rolled workpiece, the first frame of the finishing mill is arranged as a horizontal rolling mill.

[0043] Among them, after the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction is removed by the head cutting shear in step S03, before the rough rolled piece with the "tongue-shaped" defect removed is continuously rolled by the finishing rolling unit in step S04 to obtain the steel section, the steel section rolling method also includes: using a water cooling device to cool the rough rolled piece with the "tongue-shaped" defect removed, and the amount of cooling water and the pressure used in the cooling process are determined according to the inlet temperature of the rough rolled piece entering the water cooling device and the outlet temperature requirements. For this cooling process, when the cooling rate is 1°C / s and the deformation temperature of Q345B steel drops from 1000°C to 850°C, the ferrite grain size is refined from about 7.8μm to 4.6μm, and the yield strength is increased by about 60MPa, and the tensile strength is increased by about 26MPa. That is, the cooling process in this embodiment refines the grain size and improves the yield strength and tensile strength.

[0044] The purpose of using a water cooling device to cool the rough rolled piece from which the "tongue-shaped" defect has been removed in this embodiment is to improve the performance of the product and control the temperature entering the finishing mill.

[0045] The layout of the water nozzles of the water cooling device is determined according to the cross-sectional shape of the rough rolled piece rolled by the rough rolling unit, and the cooling water volume and pressure are determined according to the temperature of the rough rolled piece at the inlet and the outlet temperature requirements. In order to accurately implement the control rolling process, a high-temperature instrument can be arranged at the outlet and inlet of the water cooling device as needed to monitor the temperature change of the rough rolled piece. The rough rolled piece that has been temperature-controlled needs to go through a temperature return section. The temperature return of the core of the rolled piece will increase the sharp corners and surface temperature of the cross section to avoid overcooling of the production capacity.

[0046] For this embodiment, step S04 of continuously rolling the rough-rolled workpiece from which the "tongue-shaped" defect has been removed by using the finishing mill is specifically as follows: continuously rolling the rough-rolled workpiece that has been cooled by using the finishing mill.

[0047] Among them, step S04 uses a finishing mill to continuously roll the rough-rolled workpiece from which the "tongue-shaped" defect has been removed to obtain a steel section. Specifically, the rolling temperature of the finishing rolling process is controlled to be 850°C to 950°C, and the deformation rate of the finishing rolling process is controlled to be greater than 50%. The rough-rolled workpiece from which the "tongue-shaped" defect has been removed is continuously rolled by a finishing mill to obtain a steel section.

[0048] Among them, in step S04, the rough-rolled workpiece with the "tongue-shaped" defect removed is continuously rolled using a finishing mill, and the number of finishing mills used is ≥ 7, and the first number of the finishing mills is a horizontal rolling mill.

[0049] As mentioned above, the horizontal rolling mill is set up to enable the finishing mill group to better bite into the rough rolling workpiece.

[0050] Among them, at least one secondary high-pressure water descaling system is arranged between the 7 finishing mills; the rough-rolled workpiece from which the "tongue-shaped" defect has been removed is continuously rolled by the finishing mill group. Specifically, the rough-rolled workpiece from which the "tongue-shaped" defect has been removed is continuously rolled by the finishing mill group, and when the rolled workpiece passes through the secondary high-pressure water descaling system, the rolled workpiece is descaled by high-pressure water by the secondary high-pressure water descaling system, and the working pressure of the high-pressure water descaling system is ≥15Mpa.

[0051] Specifically, for the finishing mill group, at least one secondary high-pressure water descaling system is arranged between the finishing mills. For example, for a finishing mill with 7 trains, the secondary high-pressure water descaling system is arranged between the 3rd and 4th trains.

[0052] The multi-point, variable-pressure high-pressure water descaling system of this embodiment, that is, the setting of the primary high-pressure water descaling system and the secondary high-pressure water descaling system can effectively remove the primary iron oxide scale generated by heating and the secondary iron oxide scale generated by the rolling process, thereby improving product quality.

[0053] Wherein, step S04 uses a finishing mill to continuously roll the rough rolled piece from which the "tongue-shaped" defect has been removed to obtain a steel section, further comprising:

[0054] The rough rolled piece from which the "tongue-shaped" defect has been removed is continuously rolled by a finishing mill to obtain a finished rolled piece;

[0055] The finished rolled piece is subjected to cooling treatment, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be less than 1°C / s, so as to obtain a steel section. For this cooling treatment, similarly, when the cooling rate is 1°C / s and the deformation temperature of Q345B steel is reduced from 1000°C to 850°C, the ferrite grain size is refined from about 7.8μm to 4.6μm, and at the same time, the yield strength is increased by about 60MPa, and the tensile strength is increased by about 26MPa.

[0056] Regarding the cooling treatment of the finishing rolled pieces, the finishing rolled pieces are rolled into finished sections after passing through the finishing rolling mill. In order to improve product performance, a post-rolling controlled cooling device is arranged at the outlet of the finishing mill to perform pulse-controlled cooling on the finishing rolled pieces after rolling, that is, fast cooling and slow cooling are used intermittently, and the fast cooling should be fast and the slow cooling should be slow within a specific temperature range.

[0057] Wherein, the finishing rolled piece is cooled, and when the temperature of the finishing rolled piece is greater than 720°C, the cooling rate of the finishing rolled piece is controlled to be ≥1°C / s, and when the temperature of the finishing rolled piece is less than 720°C, the cooling rate of the finishing rolled piece is controlled to be <1°C / s, so as to obtain the steel section. Specifically, the finishing rolled piece is cooled by a pulse cooling method of alternating water cooling and air cooling, and when the temperature of the finishing rolled piece is greater than 720°C, the cooling rate of the finishing rolled piece is controlled to be ≥1°C / s, and when the temperature of the finishing rolled piece is less than 720°C, the cooling rate of the finishing rolled piece is controlled to be <1°C / s, so as to obtain the steel section.

[0058] In order to accurately implement the pulse controlled cooling process, high temperature instruments are arranged at the entrance, middle section, exit and in front of the upper cooling bed of the post-rolling controlled cooling device to monitor the corresponding temperature data.

[0059] After the finished rolled piece is cooled and the cooling rate of the finished rolled piece is controlled to be ≥1°C / s when the temperature of the finished rolled piece is greater than 720°C, and the cooling rate of the finished rolled piece is controlled to be <1°C / s when the temperature of the finished rolled piece is less than 720°C, to obtain the steel section, the steel section rolling method also includes: processing the steel section by using a flying shear or a hot saw and sending the processed steel section to a cooling bed for cooling, and the processing of the steel section by using the flying shear or the hot saw includes shearing to size, cutting the head, cutting the tail and sampling, etc.

[0060] In specific implementation, the control of the finishing rolling process and the cooling treatment after finishing rolling can be applied separately or simultaneously. Both control methods can achieve the purpose of refining grains and improving product performance.

[0061] By adopting the steel rolling method of the embodiment of the present invention, taking Q345B steel as an example, the microstructure of the steel is fine ferrite plus fine pearlite, and the yield strength of the steel is increased by 80-110 MPa, and the tensile strength is increased by 80-160 MPa. Therefore, compared with the method of increasing the yield strength and tensile strength by adding alloys in the prior art, this embodiment does not need to add alloys, thereby reducing costs; the steel obtained by the steel rolling method of the embodiment of the present invention has uniform performance and good product surface quality.

[0062] The multi-point, variable-pressure high-pressure water descaling system of the embodiment of the present invention can effectively remove the primary iron oxide scale generated by heating and the secondary iron oxide scale generated by the rolling process, thereby improving product quality. The two processes of controlled rolling in the finishing process or controlled cooling after finishing rolling are used separately or in a superimposed manner to improve product strength. In addition, for special-shaped materials, the innovative hole system design is combined with the realization of a full continuous rolling process, which can also improve production efficiency. The steel section rolling method of this embodiment is suitable for hot-rolled steel sections of small and medium specifications, including H-shaped steel, I-beams, channels, angles, and elevator guide rails, etc., providing an advanced and systematic solution for the high-quality, lightweight, green, and efficient production of steel sections.

[0063] Combine the following Figure 1 The technical solution of the embodiment of the present invention is further described.

[0064] Figure 1 FIG. 1 is a diagram of equipment corresponding to the steel section rolling process according to an embodiment of the present invention, specifically, Figure 1 As shown in the figure, the steel billet meeting the rolling requirements enters the roughing mill group for rolling after passing through a high-pressure water descaling device 1. The roughing mill group includes two types of rolling mills, namely a horizontal rolling mill 2 and a vertical rolling mill 3. The positions and numbers of the horizontal rolling mill 2 and the vertical rolling mill 3 are determined by the hole type system of the rolled product. The roughing mill group rolls the steel billet into the required intermediate section according to the rolling regulations of the product. A head-cutting flying shear 4 is arranged at the outlet of the roughing mill group to cut off the enlarged or split tongue to prevent accidents during subsequent rolling. In order to improve the performance of the product, a water cooling device 5 is arranged after the flying shear and before the next process to control the temperature entering the finishing mill group. The water nozzles of the water cooling device are arranged according to the cross section of the rolled piece rolled out by the roughing mill group. The surface shape is determined, and the cooling water volume and pressure are determined according to the inlet rolled piece temperature and the outlet temperature requirements; in order to accurately implement the controlled rolling process, high-temperature instruments 6 are arranged at the outlet and inlet of the water cooling device. The rolled piece after temperature control needs to go through a temperature return section. The temperature return of the core of the rolled piece makes the sharp corners and surface temperature of the cross section increase to avoid overcooling of the production capacity; the rolled piece that meets the requirements of controlling the rolling temperature enters the finishing mill for rolling. The finishing mill is configured with the number and form of rolling mills according to the shape of the product. The types of mills used are usually composed of horizontal rolling mills, vertical rolling mills, universal rolling mills, two-roller / universal convertible rolling mills, etc. In order to control the better bite of the rolled piece, the first frame of the finishing mill is arranged as a horizontal rolling mill 7. Figure 1 A vertical rolling mill 8 is arranged according to the needs. The rolling temperature of the finishing mill group is 850℃~950℃, and the deformation rate of the finishing rolling process is greater than 50%. In order to better improve the product quality, a secondary high-pressure water descaling device 9 is arranged at an appropriate position of the finishing mill group. According to multi-model calculation, the working pressure of the secondary high-pressure water descaling device 9 arranged in the finishing mill area is less than the working pressure of the primary high-pressure water descaling device 1 arranged before the roughing mill group, and the pressure of the high-pressure water descaling system is ≥15Mpa. After the rolled piece passes through the finishing mill group, it is rolled into a finished section. In order to improve the product performance, a post-rolling controlled cooling device is arranged at the outlet of the finishing mill. The cooling device 10 performs pulse controlled cooling on the rolled piece after rolling, that is, fast cooling and slow cooling are used intermittently, and the cooling speed of the rolled piece is accurately controlled within a specific temperature range. In order to accurately implement the pulse controlled cooling process, high-temperature instruments 6 are arranged at the entrance, middle section, exit and before the upper cooling bed of the post-rolling controlled cooling device. The rolled piece after post-rolling cooling is cut into size according to needs by the spare shear 11 and then sent to the cooling bed 12 for cooling. In order to accurately implement the post-rolling cooling process and ensure the stability of the directional performance of the product rod, the spare shear 11 is arranged after the post-rolling cooling device 10.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for rolling a section steel, characterized in that: The method comprises: The steel billet is subjected to at least one high-pressure water descaling treatment using a primary high-pressure water descaling system, and the pressure of the high-pressure water descaling system is controlled to be ≥15Mpa during the high-pressure water descaling treatment process; The treated steel billet is continuously rolled by a rough rolling mill to obtain a rough rolled product; Use the flying shear to remove the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction; The rough rolled piece from which the "tongue-shaped" defect has been removed is continuously rolled using a finishing mill to obtain the steel section.

2. The steel section rolling method according to claim 1, characterized in that: The steel billet is subjected to at least one high-pressure water descaling treatment using a primary high-pressure water descaling system, and the pressure of the high-pressure water descaling system is controlled to be ≥15 MPa during the high-pressure water descaling treatment. Specifically: The steel billet is descaled by high pressure water at least once using a high pressure water descaling system, and the descaling working pressure is ≥20Mpa; if the steel billet is descaled by high pressure water multiple times, the minimum working pressure of the control system is ≥15Mpa.

3. The steel section rolling method according to claim 1, characterized in that: In the continuous rolling of the processed steel billet by the roughing mill, the number of the roughing mills used is ≥5.

4. The steel section rolling method according to claim 1, characterized in that: After the "tongue-shaped" defect formed at the end of the rolled piece in the extension direction is removed by the head-cutting flying shear, the method further comprises: The rough rolled piece from which the "tongue-shaped" defect has been removed is cooled by a water cooling device, and the amount and pressure of cooling water used in the cooling process are determined according to the inlet temperature of the rough rolled piece entering the water cooling device and the outlet temperature requirements; The method of continuously rolling the rough rolled piece from which the "tongue-shaped" defect has been removed by using a finishing mill is specifically as follows: continuously rolling the rough rolled piece that has been cooled by using a finishing mill.

5. The steel section rolling method according to claim 1, characterized in that: The method of continuously rolling the rough rolled piece from which the "tongue-shaped" defect has been removed by the finishing mill to obtain the steel section is as follows: The rolling temperature of the finishing rolling process is controlled to be 850°C to 950°C, and the deformation rate of the finishing rolling process is controlled to be greater than 50%. The rough-rolled piece with the "tongue-shaped" defect removed is continuously rolled using a finishing rolling unit to obtain the steel section.

6. The steel section rolling method according to claim 5, characterized in that: In the continuous rolling of the rough rolled piece with the "tongue-shaped" defect removed by the finishing mill, the number of the finishing mills used is ≥ 7, and the first one of the finishing mills is a horizontal rolling mill.

7. The steel section rolling method according to claim 6, characterized in that: At least one secondary high-pressure water descaling system is installed between the 7 finishing mills; The method of continuously rolling the rough rolled piece with the "tongue-shaped" defect removed by the finishing mill is specifically as follows: continuously rolling the rough rolled piece with the "tongue-shaped" defect removed by the finishing mill, and when the rolled piece passes through the secondary high-pressure water descaling system, the secondary high-pressure water descaling system is used to perform high-pressure water descaling on the piece, and the working pressure of the high-pressure water descaling system is ≥15Mpa.

8. The steel section rolling method according to claim 1, characterized in that: The method of continuously rolling the rough rolled piece from which the "tongue-shaped" defect has been removed by a finishing mill to obtain the steel section further comprises: The rough rolled piece from which the "tongue-shaped" defect has been removed is continuously rolled by a finishing mill to obtain a finished rolled piece; The finished rolled piece is cooled, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section.

9. The steel section rolling method according to claim 8, characterized in that: The finished rolled piece is subjected to cooling treatment, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section as follows: The finished rolled piece is cooled by a pulse cooling method that alternates between water cooling and air cooling, and when the temperature of the finished rolled piece is greater than 720°C, the cooling rate of the finished rolled piece is controlled to be ≥1°C / s, and when the temperature of the finished rolled piece is less than 720°C, the cooling rate of the finished rolled piece is controlled to be <1°C / s, so as to obtain the steel section.

10. The steel section rolling method according to claim 8, characterized in that: After the finished rolled piece is cooled and the cooling rate of the finished rolled piece is controlled to be ≥1°C / s when the temperature of the finished rolled piece is greater than 720°C, and the cooling rate of the finished rolled piece is controlled to be <1°C / s when the temperature of the finished rolled piece is less than 720°C, to obtain the steel section, the method further includes: processing the steel section by using a flying shear or a hot saw and sending the processed steel section to a cooling bed for cooling.

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