System for producing steel hole pattern for cutting and rolling method

Abstract

The invention relates to the technical field of metal pressure machining, and discloses a hole pattern system for producing cutting steel and a rolling method.The system is characterized in that the hole pattern system is arranged on a continuous rolling mill which is horizontally and vertically arranged alternately and is composed of a rough rolling hole pattern set, an intermediate rolling hole pattern set and a finish rolling hole pattern set which are sequentially connected; the rough rolling front end hole pattern group is used for carrying out preliminary rolling and powerful scale breaking on the steel billets and at least comprises a box type hole pattern with convexity at the groove bottom; the main rolling hole pattern group is used for executing main pressing and stable rolling and comprises divergence angle round hole patterns and elliptical hole patterns which are alternately arranged; and the finish rolling finished product pass group is used for carrying out final size and shape finishing on the rolled piece, and the pass of the finished product frame is a double-arc divergence angle round pass. By accurately controlling the heating, rolling and cooling temperatures and cooperating with the hole pattern system, oxide scales can be effectively removed, the stability of the rolling process is improved, and the size precision and the surface quality of the finished round steel are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal pressure processing, in particular to a hole type system for producing cutting steel and a rolling method. BACKGROUND

[0002] In the hot continuous rolling production of bars, a continuous rolling mill composed of rough rolling, intermediate rolling and finishing rolling mill groups is usually adopted to roll the heated square billet into the final required size of round steel through multiple pass hole types. The hole type system, as the core tool for realizing this plastic deformation process, its design directly determines the stability, efficiency of production and the quality of the final product.

[0003] However, in the high temperature rolling process, the surface of the billet inevitably generates hard and brittle primary iron oxide scale, and secondary iron oxide scale generated between passes. The existing hole type system has limited ability to remove these iron oxide scales, especially in the early stage of rolling, it is difficult to effectively break and peel off the firmly adhered primary iron oxide scale. These residual iron oxide scales are easily pressed into the steel matrix during subsequent rolling, resulting in defects such as pits and dents on the surface of the finished round steel, which seriously affects its surface quality and is extremely disadvantageous for subsequent cutting processing applications that require high surface smoothness.

[0004] In addition, in the traditional oval-round hole type system, in order to achieve efficient rolling, the oval hole type is designed to realize a larger pass reduction, but when the oval section of the rolled piece enters the subsequent round hole type, its spread is often difficult to accurately control. If the entrance of the round hole type is not properly designed, it is easy to cause the phenomenon of excessive filling of the hole type. This not only causes the metal to accumulate at the guide device, causing impact and damage, but also may cause the rolled piece to twist, swing and even fall between the racks, causing serious production accidents, which threatens the stable operation of the production line.

[0005] At the same time, the existing technology also rarely specifically strengthens the control of the finished product geometric precision in the design of the finished pass hole type. In the final forming pass, the limiting ability of the rolled piece spread is insufficient, resulting in the rolled finished round steel often having a large ovality, and the size precision is difficult to meet the increasingly high market requirements, reducing the product qualification rate and added value. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a hole type system for producing cutting steel and a rolling method, which solves the technical problem of providing a hole type system for producing cutting steel that can effectively remove iron oxide scale, stabilize the rolling process and improve the size precision of the finished product, and a corresponding rolling method.

[0007] To achieve the above object, the present application is implemented by the following technical solutions: A production cutting steel pass system, the pass system is arranged on a continuous rolling mill with flat and vertical alternating arrangement, and is composed of a rough rolling pass group, a medium rolling pass group and a finish rolling pass group which are sequentially connected; A rough rolling front-end pass group for primary rolling and strong scale breaking of the billet, the group at least contains a box pass with a convexity on the groove bottom; A main rolling pass group for performing main reduction and stable rolling, the group contains alternatingly arranged spread angle round passes and elliptical passes; A finish rolling finished product pass group for final size and shape finishing of the rolled piece, and the pass of the finished product rack is a double circular arc spread angle round pass.

[0008] The design effectively breaks and peels the primary oxide scale on the surface of the high-temperature square billet through the initial box pass sequence, and establishes a stable basic material shape. The subsequent round-elliptical pass alternating system is used to stably deform the billet to the final size.

[0009] Preferably, the first three racks of the rough rolling mill group are in sequence: The No. 1 horizontal rack is configured as a flat box pass; The No. 2 vertical rack is configured as a vertical box pass; The No. 3 horizontal rack is configured as a flat box pass.

[0010] In a specific embodiment, the flat box pass of the No. 1 horizontal rack has a convexity of 2mm on the groove bottom. The convexity structure causes the rolling force to be guided and concentrated in the center line area of the square billet wide surface during rolling, thereby generating stress concentration in this area to cause the primary oxide scale on the surface of the square billet to break. The flat box pass of the No. 3 horizontal rack has a convexity of 1mm on the groove bottom. This structure is used to apply concentrated normal stress to the rolled piece after being flattened in the previous pass, to further break and promote the peeled oxide scale from the matrix.

[0011] Preferably, the round pass is a spread angle round pass, and the elliptical pass is a single circular arc elliptical pass. This combination can control the spread of the rolled piece while ensuring sufficient pass reduction, and continuously remove the secondary oxide scale.

[0012] In one specific embodiment, the expansion angle round pass is arranged in a vertical stand, and the pass is flanked by straight lines tangent to the main circular arc, and the angle between the straight lines and the horizontal line is 30°. The design of the 30° expansion angle provides non-restricted metal flow space for the rolled piece coming out of the previous pass of the elliptical pass, and avoids surface defects such as folding and scratching caused by overfilling. Meanwhile, the tangent point between the main circular arc and the straight line forms a geometric mutation, which plays a scraping role on the surface of the rolled piece during rolling, thereby removing the newly generated secondary scale on the elliptical pass.

[0013] Preferably, the finishing pass set comprises a pre-finished stand pass and a finished stand pass.

[0014] In one specific embodiment, the finished stand pass is a double circular arc expansion angle round pass.

[0015] In a more specific embodiment, the central angle of the main circular arc of the double circular arc expansion angle round pass of the finished stand pass is smaller than the central angle of the main circular arc of the expansion angle round pass in the rough and intermediate rolling pass set and the pre-finished stand pass. This relationship can be represented by the following formula: ; In the formula, is the central angle of the main circular arc of the double circular arc expansion angle round pass of the finished stand (K1), is the central angle of the main circular arc of the expansion angle round pass on any vertical stand before the finished stand (K1).

[0016] Reducing the central angle of the main circular arc of the finished stand pass has the technical effect of shortening the unsupported arc length of the rolled piece in the pass, enhancing the restriction on the spread deformation of the rolled piece, thereby improving the dimensional accuracy of the final finished round steel, specifically reducing the ovality of the rolled piece.

[0017] Preferably, the pass system is composed of 12 stand passes, including 10 stand passes arranged in the rough rolling mill set and the intermediate rolling mill set, and 2 stand passes arranged in the finishing rolling mill set.

[0018] The second aspect of the present application provides a rolling method for producing cutting steel, which adopts the pass system of any of the foregoing and comprises the following steps: (a) heating step: heating the billet to a soaking temperature of 1080°C to 1140°C for rolling; (b) multi-pass rolling step: multi-pass rolling of the heated billet in step (a) in a horizontal-vertical alternating manner; during rolling, an on-line water cooling process is arranged after at least one of the rough rolling, intermediate rolling or finishing rolling stages to control the temperature of the rolled piece before entering the next rolling stage; (c) Control cooling step: the finished round steel after all rolling passes is directly conveyed to the cooling bed on the rolling line for air natural cooling.

[0019] The method ensures that the cutting steel is deformed in the austenite region with good plasticity by precisely controlling the temperature parameters of the heating and rolling processes. In particular, by controlling the higher finishing rolling final rolling temperature and the upper cooling bed temperature, and combining air natural cooling, the self-heat of the rolled piece is utilized for slow cooling, which helps to form a microstructure suitable for cutting processing and improves the mechanical properties of the final product.

[0020] The present application provides a kind of production cutting steel pass system and rolling method. With the following beneficial effects: 1. By setting the combination of flat box pass, vertical box pass and flat box pass at the front end of the rolling sequence, especially by setting the convexity at the groove bottom of the flat box pass and the flat box pass, concentrated stress can be generated on the primary iron oxide scale on the surface of the high-temperature bloom at the initial stage of rolling, which effectively breaks the primary iron oxide scale. Combined with the expansion angle round pass set in the subsequent pass, the tangent point of the main circular arc and the straight line plays a scraping role on the surface of the rolled piece during rolling, thereby continuously removing the secondary iron oxide scale, and finally obtaining the finished round steel with high surface finish.

[0021] 2. The present application adopts a flat-stand alternation arrangement and configures an expansion angle round pass with an expansion angle of 30°, which provides non-restricted metal flow space for the rolled piece from the previous pass of the elliptical pass, effectively avoiding the accumulation of metal, impact of guide and guard equipment, and twisting or dumping of the rolled piece due to overfilling of the pass, thereby significantly improving the stability of the entire hot continuous rolling process and reducing the production accident rate.

[0022] 3. The present application uses a double circular arc expansion angle round pass with a smaller central angle of the main circular arc in the finished product stand. Compared with the finished product front stand and the previous expansion angle round pass, this design shortens the unsupported arc length of the rolled piece in the pass, enhances the restriction ability of the rolled piece width expansion deformation, and this strong restriction forces the metal to fill the pass profile more accurately, effectively suppressing the ovality of the finished product rolled piece, thereby significantly improving the dimensional accuracy and geometric shape regularity of the final finished round steel. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The present application is a schematic diagram of the overall structure of the pass system; Figure 2 The present application is a schematic diagram of the pass sequence arrangement; Figure 3 The present application is a schematic diagram of the cross section of the flat box pass; Figure 4 The present application is a schematic diagram of the cross section of the main rolling section expansion angle round pass; Figure 5This is a cross-sectional schematic diagram of the double-circular arc expansion angle circular hole type of the finished product frame of the present invention; Figure 6 This is a schematic diagram of the rolling method of the present invention; Figure 7 This is a schematic diagram of a die system and rolling method for producing Φ40mm cutting steel according to the present invention; Figure 8 This is a schematic diagram of the roughing mill front-end stand pass profile of the present invention.

[0024] in, Figure 7 In the middle section, 1. Billet rolling mill; 2. Six roughing mill stands; 3. Flying shear one; 4. Four intermediate mill stands; 5. Primary water cooling box; 6. Flying shear two; 7. Four finishing mill stands; 8. Secondary water cooling box; 9. Flying shear three; 10. Two finishing mill stands; 11. Tertiary water cooling box; 12. Flying shear four; 13. Cooling bed. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] See attached document Figure 1 The schematic diagram shown illustrates a roll pass system for producing cutting steel provided by the present invention. This roll pass system, along the rolling direction, sequentially comprises: a roughing mill front-end roll pass group, a main rolling roll pass group, and a finishing mill finished product roll pass group. These three roll pass groups are physically connected in series on a hot continuous rolling production line arranged in an alternating horizontal and vertical configuration of horizontal and vertical stands.

[0027] The roughing mill's front end pass group is located at the beginning of the rolling line to receive and process the initial square billet. This pass group consists of the passes from the three front stands of the rolling line, in the following sequence: a flat box pass on the No. 1 horizontal stand, a vertical box pass on the No. 2 vertical stand, and a flat box pass on the No. 3 horizontal stand. The primary function of this sequence is to break up and peel off the initial iron oxide scale on the surface of the high-temperature square billet, and to establish a stable rectangular cross-section profile for subsequent rolling.

[0028] Following this is the main rolling pass group, which constitutes the main section for dimensional reduction deformation during rolling. In this embodiment, this pass group consists of passes from the No. 1 stand to the finished product stand (K2). The pass types are configured with an alternating combination of expanded-angle round passes and single-circular-arc elliptical passes. While achieving efficient compression of the workpiece cross-sectional dimensions, the specific geometry of the expanded-angle round passes also helps maintain the workpiece's posture stability during high-speed rolling and continuously removes secondary iron oxide scale generated during the rolling process.

[0029] The design of the single-arc elliptical bore has its major-minor axis ratio controlled within the range of 1.25 to 1.40. This major-minor axis ratio is designed to ensure that while providing sufficient reduction per pass, it can stably provide a regular-shaped and appropriately filled feed material for subsequent expansion-angle circular bores.

[0030] At the end of the rolling line is a finishing pass group, which in this embodiment is the pass for the finishing stand (K1). It employs a double-circular-arc expansion angle circular pass. The design of this pass focuses on controlling the dimensions and geometry of the final product. Its core design lies in the fact that the center angle of the main circular arc of this pass is smaller than the center angle of the main circular arc of all the expansion angle circular passes in the main rolling pass group. This geometric constraint is used to suppress the widening of the rolled piece in the final forming pass, thereby obtaining finished round steel with low ellipticity and high dimensional tolerances. This constraint can be expressed by the following formula: ; In its formula, The main arc center angle of the double-arc expansion angle circular hole type of the finished frame (K1) is open. The main arc center angle of the expansion angle circular hole type on any vertical frame before the finished product rack (K1).

[0031] In a specific numerical embodiment, the expansion angle circular pass type set in the main rolling pass group has a main arc center angle. The angle is set to 105°; while the double-arc expansion angle circular pass set in the finishing mill pass group has a main arc center angle of 105°. The angle is set to 95°. This setting clearly satisfies the requirement. The geometric conditions.

[0032] See attached document Figure 2 Appendix Figure 3 Appendix Figure 4 Appendix Figure 5 and appendix Figure 8 The following provides a detailed description of each stage of the hole-type system in the embodiments of the present invention.

[0033] The roughing mill front end pass group consists of the passes from stands 1, 2, and 3 at the beginning of the rolling line. (See attached diagram.) Figure 2The No. 1 horizontal stand is configured as a flat box pass, characterized in that a 2mm convexity is machined on the groove bottom. When the high-temperature square billet enters the stand, the rolling force is concentratedly applied to the centerline area of the square billet wide surface through the convexity structure, and the local compressive stress of the area is significantly increased, so that the brittle primary oxide scale on the surface of the square billet is broken.

[0034] After passing through the No. 1 horizontal stand, the rolled piece enters the No. 2 vertical stand, which is configured as a vertical box pass. The vertical box pass is used to roll the rolled piece rotated by 90 degrees, and its main function is to compress the other two sides of the rolled piece and cooperate with the deformation of the previous pass to further loosen and peel the cracked oxide scale.

[0035] Subsequently, the rolled piece enters the No. 3 horizontal stand, which is configured as a flat box pass with a 1mm convexity on the groove bottom. This structure applies concentrated normal stress to the surface not directly affected by the convexity in the previous pass, completes the breaking of the oxide scale on all four surfaces of the initial square billet, and finally stably shapes the rolled piece into a rectangular material with uniform cross section, providing a prerequisite for stable biting and rolling of the subsequent main rolling pass group.

[0036] The main rolling pass group is composed of passes from No. 4 stand to finished product stand (K2), and in this embodiment, the pass group is composed of expansion angle round passes arranged on vertical stands (4V, 6V, 8V, 10V) and single circular arc elliptical passes arranged on horizontal stands (5H, 7H, 9H, K2). Referring to the alternative sequence shown in the accompanying Figure 3 The single circular arc elliptical pass is used to achieve the main reduction of the cross-sectional size of the rolled piece, and the expansion angle round pass receives the rolled piece from the previous elliptical pass.

[0037] Referring to the accompanying Figure 4 The geometry of the expansion angle round pass is described. The two sides of the pass are composed of straight lines tangent to the main circular arc, and the angle between the straight lines and the horizontal line is set to 30°. The design of the 30° expansion angle provides an unconstrained metal flow space for the head of the rolled piece with a large tendency to spread out from the elliptical pass, avoids surface defects such as scratching and folding caused by excessive filling of metal in the pass, and prevents the rolled piece from tilting and twisting between stands, ensuring the continuity and stability of the high-speed rolling process. At the same time, at the tangent point of the main circular arc and the expansion straight line, a geometric shape mutation is formed, which mechanically scrapes the surface of the rolled piece when it passes through, thereby removing the newly generated secondary oxide scale from the matrix.

[0038] The finish rolling finished product pass group is the pass of the finished product stand (K1). Referring to the accompanying Figure 5This hole type is a double-circular-arc expansion angle circular hole. The design of this hole type focuses on controlling the dimensional accuracy of the final product. Its core structural feature lies in the central angle of the main arc of this double-circular-arc expansion angle circular hole. Numerically smaller than the center angle of the main arc of any expansion angle circular pass in the main rolling pass group. This geometric relationship (i.e.) This design allows for a more compact enclosure of the rolled piece by the roll pass, shortening the unsupported arc length of the piece within the pass. This structure enhances the physical constraint of the rolls on the transverse metal flow (i.e., widening) of the rolled piece, forcing the metal to extend further along the rolling direction. The direct technical effect is the suppression of cross-sectional shape distortion of the finished product as it exits the stand, significantly reducing the ellipticity of the final round steel (i.e., the difference between the maximum and minimum diameters of the same cross section), thereby improving the geometric accuracy of the product.

[0039] See attached document Figure 6 This invention also provides a rolling method for producing cutting steel. This method employs the pass system described in the foregoing embodiments, which consists of a roughing mill front end pass group, a main rolling pass group, and a finishing mill finished product pass group. The method includes the following steps: First, the 165mm × 165mm square billet undergoes heat treatment. This heating process takes place in a multi-stage furnace and is divided into three temperature-controlled zones. The billet first enters the preheating zone, where the temperature is controlled between 700℃ and 900℃. The purpose of this zone is to allow the billet's temperature to rise gradually, thereby reducing the temperature difference between the inside and outside of the billet and preventing thermal stress cracks caused by rapid heating.

[0040] The preheated billet is fed into a heating section where the temperature is controlled between 1050°C and 1180°C. Within this temperature range, the billet is rapidly heated to the target rolling temperature range, causing its internal structure to completely transform into austenite suitable for plastic deformation.

[0041] Subsequently, the billet enters the soaking zone, where the temperature is controlled between 1080℃ and 1140℃. The billet stays in this zone for a predetermined time to eliminate the cross-sectional temperature inhomogeneity that occurs after rapid heating, ensuring uniform temperature from the core to the surface of the billet. This provides conditions for obtaining consistent metal flow and deformation resistance in subsequent rolling passes.

[0042] After being heated evenly, the billet exits the furnace and enters the rolling process. By controlling the mill speed and furnace exit rhythm, the initial rolling temperature of the billet entering the No. 1 stand (i.e., the starting stand of the roughing mill's front end pass group) is ensured to be controlled between 980℃ and 1030℃. This temperature point ensures that the billet possesses good plasticity while the primary iron oxide scale on its surface is in a brittle state, which is conducive to effective breakage under the action of the flat box pass.

[0043] The bloom is rolled through 12 stands in turn. At the end of the rolling process, the outlet temperature of the finishing rolling mill is precisely controlled, that is, the temperature of the rolled piece at the outlet of the pre-product stand (K2) is controlled at 970-1010 DEG C. The control of the final rolling temperature directly determines the austenite grain state before the rolled piece enters the cooling stage, and is a key process parameter affecting the microstructure and mechanical properties of the final product.

[0044] The finished round steel after rolling is sent to the cooling bed at a temperature of 980-1010 DEG C and is subjected to air natural cooling. This high-temperature cooling system on the bed and air slow cooling is a kind of controlled cooling using the residual heat stored by the rolled piece. Compared with the rapid cooling by water spraying, the air natural cooling has a slow cooling rate, which is beneficial to the full transformation of the austenite to ferrite and pearlite, and can form a relatively soft metallographic structure (pearlite > 60% + ferrite) suitable for cutting processing, thereby improving the cutting performance of the final cutting steel product.

[0045] Referring to the accompanying drawings Figure 7 The Φ40mm production process of the cutting steel according to the present application is: bloom → heating → rough rolling → flying shear cutting → intermediate rolling → first-stage water cooling → flying shear cutting → first-stage finishing rolling → second-stage water cooling → flying shear cutting → second-stage finishing rolling → third-stage water cooling → flying shear cutting to length → cooling bed air cooling → length cutting → inspection, packaging and warehousing.

[0046] Specifically, the cutting steel production process adopted by the present application starts from uniformly heating the bloom rolled piece 1 in the heating furnace to a predetermined temperature, then the high-temperature bloom enters the rough rolling mill group 2 composed of six rolling mills for preliminary large reduction rolling and strong scale breaking, the irregular part of the head after rolling is cut off by the flying shear 1 3, then the rolled piece enters the intermediate rolling mill group 4 composed of four rolling mills for continuous rolling, in order to precisely control the temperature of the subsequent process, the rolled piece passes through the first-stage water cooling box 5 for initial online cooling, and is subjected to necessary process cutting by the flying shear 2 6, then the rolled piece passes through the first-stage finishing rolling mill group 7 composed of four rolling mills and the second-stage water cooling box 8 for the first-stage finishing rolling and the second-stage temperature regulation, after being trimmed again by the flying shear 3 9, the rolled piece enters the second-stage finishing rolling mill group 10 composed of two rolling mills for final size finishing and surface forming. The finished steel after rolling is subjected to final wire drawing temperature control by the third-stage water cooling box 1 1 before entering the cooling bed, and is cut to the predetermined length by the flying shear 4 12, finally, the high-temperature steel is conveyed to the cooling bed 1 3 for air natural cooling to form the required metallographic structure, and after cooling, is subjected to length cutting, inspection and packaging and finally warehoused.

[0047] By using the above pass system and rolling method, the finished round steel with smooth surface and without rolled-in defects of iron oxide scale can be finally obtained. In a specific production example, for the round steel with a target specification of Φ22 mm, the ovality of the finished product can be stably controlled within 0.10 mm, and the size tolerance meets the high-precision grade requirement.

[0048] While the embodiments of the application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A system for producing cutting profiles for steel, characterized in that, include: The pass system is installed on a continuous rolling mill with alternating horizontal and vertical sections. The pass system includes a roughing mill pass group, an intermediate mill pass group, and a finishing mill pass group, which are connected sequentially. The roughing mill front end pass group is used for preliminary rolling and strong descaling of steel billets. This group includes at least one box-shaped pass with a convex bottom. The main rolling pass group, used to perform the main reduction and stabilization rolling, includes alternating expansion-angle round and elliptical passes; The finishing mill pass assembly is used to perform final dimensional and shape finishing on the rolled workpiece, and the pass shape of the finishing mill stand is a double-circular arc expansion angle circular pass shape.

2. The system for producing cutting steel profiles according to claim 1, characterized in that, The pass patterns of the first three stands of the roughing mill are as follows: The No. 1 horizontal frame is configured with a flat box-shaped hole type; The No. 2 vertical rack is configured with a vertical box-shaped hole type; The No. 3 horizontal frame is configured with a flat box-shaped hole.

3. The system for producing cutting steel profiles according to claim 1, characterized in that, The flat box-shaped hole of the No. 1 horizontal frame has a convexity of 1mm to 3mm at the bottom of the groove, and the flat box-shaped hole of the No. 3 horizontal frame has a convexity of 1mm to 2mm at the bottom of the groove.

4. The system for producing cutting steel profiles according to claim 1, characterized in that, The circular hole type is an expanded-angle circular hole type, and the elliptical hole type is a single-arc elliptical hole type.

5. A system for producing cutting steel profiles according to claim 4, characterized in that, The expansion angle circular hole is set on the vertical frame, and its two sides are formed by straight lines tangent to the main circular arc, with the angle between the straight lines and the horizontal line being 30°.

6. A system for producing cutting steel profiles according to claim 1, characterized in that, The finishing mill pass group includes the pre-finishing stand pass and the finishing stand pass.

7. A system for producing cutting steel profiles according to claim 6, characterized in that, The finished product rack has a double-circular-arc expanded-angle circular hole.

8. A system for producing cutting steel profiles according to claim 1, characterized in that, The center angle of the double-circular arc expansion angle circular hole in the finished product frame hole pattern is smaller than that of the expansion angle circular hole in the roughing and intermediate rolling hole pattern group and the finished product front frame hole pattern.

9. A system for producing cutting steel profiles according to claim 1, characterized in that, The pass system consists of 12 stands of passes, including 10 stands of passes located in the roughing mill and intermediate mill, and 2 stands of passes located in the finishing mill.

10. A rolling method for producing cutting steel profiles, applied to a cutting steel profile production system as described in any one of claims 1-9, characterized in that, Includes the following steps: (a) Heating step: The billet is heated to a homogenization temperature of 1080°C to 1140°C in preparation for rolling; (b) Multi-pass rolling process: The heated square billet in step (a) is subjected to multiple passes of alternating horizontal and vertical rolling; during the rolling process, an online water cooling process is set after at least one stage of roughing, intermediate rolling or finishing rolling to control the temperature of the rolled piece before entering the next rolling stage; (c) Controlled cooling process: The finished round steel bars after all rolling passes are directly transported to the cooling bed on the rolling line for natural air cooling.

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