Method for stabilizing two-segmentation rolling line difference through pre-segmentation hole pattern

Abstract

The invention discloses a method for stabilizing a two-segmentation rolling line difference through a pre-segmentation hole pattern, belongs to the technical field of steel rolling segmentation rolling, and solves the problem that waste products or steel piling faults are frequently generated due to large line differences after grooves and guides are changed in the existing deformed steel bar production process. The method comprises the following steps that inlet guides and outlet guides of all racks of all finishing mill groups are installed and aligned, the opening degree of the guides is adjusted, the sizes of rolled pieces are matched, and deformed steel bars are rolled into round holes in an intermediate rolling mill after being rolled by a roughing rolling mill group and enter the finishing mill groups along with a production line; and rolling the deformed steel bar in a 13 #-18 # rolling mill of a finishing mill group, segmenting the deformed steel bar through a 16 # rolling mill, shaping the deformed steel bar through a 17 # rolling mill and a 18 # rolling mill, and outputting a finished product. By increasing the fullness of the rolled piece in the finishing mill group, the rolled piece is automatically aligned and centered in the rolling process, line difference control of two-slitting rolling is stabilized, and the problem that the line difference is large in the two-slitting rolling process is obviously solved.

Description

Technical Field

[0001] The invention belongs to the technical field of steel rolling slitting and rolling, and in particular relates to a method for stabilizing the difference between two slitting rolling lines through a pre-slitting pass type. Background Art

[0002] The two-cut rolling technology for rebar is a production process that uses specially designed hole types and guide devices to cut the rolled piece longitudinally during the rolling process, and then performs two-line rolling at the same time in the subsequent frames, thereby rolling two finished products at one time. Compared with traditional single-line rolling, the two-cut rolling technology has the advantages of greatly increasing the output of the rolling line, reducing energy consumption and costs, and saving equipment investment. Therefore, the two-cut rolling technology is mainly used in the production of small-size rebar to achieve the purpose of increasing output, reducing costs, and reducing rolling passes.

[0003] In current production, the rolled piece is free to run in the section between the guide and the hole type, especially the head and tail parts of the rolled piece. After changing the groove and the guide, quality defects such as excessive geometric dimensions and negative differences still often occur, or steel piling failures occur due to too large line differences. Therefore, the design reduces the dependence of the rolled piece on the guide during the hole matching process by matching the hole type with the material type of the rack, so that the rolled piece can be stably rolled in the hole type, the line difference can be accurately controlled in time, and the finished product with geometric dimensions that meet the quality requirements can be rolled out as soon as possible, which plays a key role in the production stability and index improvement of the cutting and rolling of this specification. For this reason, the present invention starts with the design of the pre-cutting rack hole type, so that the size of the rolled piece and the hole type of the rack are strictly matched, and the rack hole type system is redesigned through measurement and calculation under the condition that the original process does not change. Summary of the invention

[0004] The invention provides a method for stabilizing the rolling line difference between two cuts by pre-cutting the pass type, so as to solve the problem that in the current production of threaded steel, waste products or steel pile failures are frequently generated due to large line difference after changing grooves and guides.

[0005] The technical solution of the present invention is: a method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type, comprising the following steps: A. Align the inlet and outlet guides of each stand of each finishing mill, adjust the guide opening to match the size of the rolled piece, and ensure that the roll gaps on both sides of each stand of the finishing mill are consistent; B. After being rolled by the rough rolling mill, the rebar is rolled into a round hole shape by the intermediate rolling mill and then enters the finishing rolling mill along the production line; C. Rebar is rolled in the finishing mill group 13#-18# rolling mills, among which 13# is a flat roll without hole type, 14# is a box-type hole type, 15# is a pre-cut hole type, 16# is a cut hole type, 17# is a flat oval hole type, and 18# is a finished hole type. The rebar is cut by the 16# rolling mill, shaped by the 17# and 18# rolling mills, and then the finished product is output.

[0006] As a further improvement of the present invention, each line segment and arc segment of the hole profile is tangentially connected.

[0007] As a further improvement of the present invention, in step C, the fullness of the width of the 15# pre-cutting rack rolled piece size compared with the width of the rack pass is more than 98%, and the fullness is not higher than 100%.

[0008] As a further improvement of the present invention, for the 15# rolling mill, according to the actual width of the rolled piece in this stand, by designing the hole parameters of the arc segment radius R and the arc center distance L, the hole width B is appropriately reduced without changing other hole parameters, thereby increasing the filling degree of the rolled piece in the hole to meet the requirements.

[0009] As a further improvement of the present invention, the reduction value of the cross-sectional area of ​​the pass profile of the 15# rolling mill should be no greater than 3%.

[0010] The beneficial effects of the present invention are as follows: the present invention increases the fullness of the rolled piece in the finishing mill, strengthens the clamping effect of the 15# mill pre-cutting pass on both sides of the rolled piece, enables the rolled piece to automatically align and center during the rolling process, ensures that the cross-sectional areas on both sides of the rolled piece are consistent after pre-cutting, stabilizes the line difference control of the two-cut rolling, significantly improves the problem of large line difference during the two-cut rolling process, greatly reduces the amount of product rejection, and reduces the difficulty of operation, eliminates the steel pile failure caused by large line difference, and promotes the improvement of various indicators. The present invention saves time and labor, has strong adaptability, high safety, effectively improves the negative deviation control accuracy, and greatly improves the production qualification rate of threaded steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the pass type of the 13#-18# finishing mill; Figure 2 Produce cross-sectional drawings of rolled products for the 14# rolling mill; Figure 3 Produce cross-sectional drawings of rolled products for the 15# rolling mill; Figure 4 This is the hole diagram of 15# rolling mill; Figure 5 This is the schematic diagram of the guide and guard arrangement of the 15# rolling mill; In the figure: 1-upper roller, 2-inlet guide assembly, 3-lower roller, 201-guide wheel, A0-distance from guide wheel to hole profile. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below in conjunction with specific implementation modes.

[0013] Embodiment 1: Application example of the method of stabilizing the difference between two cutting rolling lines by pre-cutting pass type of the present invention: The steps include: A. Align the inlet and outlet guides of each stand of each finishing mill, adjust the guide opening to match the size of the rolled piece, and ensure that the roll gaps on both sides of each stand of the finishing mill are consistent; B. After being rolled by the rough rolling mill, the rebar is rolled into a round hole shape by the intermediate rolling mill and then enters the finishing rolling mill along the production line; C. Rebar is rolled in the finishing mill group 13#-18# rolling mills, among which 13# is a flat roll without hole type, 14# is a box-type hole type, 15# is a pre-cut hole type, 16# is a cut hole type, 17# is a flat oval hole type, and 18# is a finished hole type. The rebar is cut by the 16# rolling mill, shaped by the 17# and 18# rolling mills, and then the finished product is output. For the 15# rolling mill, according to the actual width of the rolled product in this stand, the hole parameters of the arc segment radius R and the arc center distance L are designed. When other hole parameters remain unchanged, the hole width B is appropriately reduced to increase the filling degree of the rolled product in the hole to meet the requirements.

[0014] It is used for rolling rebar by two-cutting process. Most enterprises use it to produce Φ16-22mm rebar. The following description takes Φ22mm two-cutting rebar as an example. Φ22mm specification adopts two-cutting rolling. The rolled piece is cut longitudinally by the finishing mill. The pass is designed to connect the smooth tangent of each section. The pass height H, roll gap value S, cutting blade arc radius r, cutting blade gap h and other parameters remain unchanged. Figure 4 As shown, the arc radius R and arc center distance L are redesigned according to the determined hole width B. When the pre-cut hole width B of Φ22mm specification is 55mm, the width of the rolled piece is 54.3mm after multiple measurements. According to the measured actual width b of the rolled piece and the pre-cut hole width B, the rolled piece fullness η is calculated. The fullness formula is η=b / B×100%, and the fullness η=54.3 / 55×100%=98.7%, which meets the design requirements.

[0015] The reduction in cross-sectional area of ​​the 15# rolling mill hole should not exceed 3%.

[0016] Split rolling requires that the area of ​​each split rolled piece should be equal or approximately equal, otherwise there will be a large difference between the two lines, which is not conducive to negative difference control. When the line difference is serious, it is very easy to produce scrap or steel pile failure. Line difference control is the difficulty of split rolling control, and it is also the key to product quality control and negative deviation rolling. In the two-slit rolling process, the roll gaps on both sides of each stand of the finishing mill, especially the 17# and 18# stands of the rolling mill, must be strictly consistent, such as Figure 5As shown in the figure, the 15# and 16# inlet guides are strictly aligned with the center line of the hole profile. On this basis, the key frame for line difference control is the 15H pre-cutting frame. The pre-cutting frame rolls the rolled piece into parallel rolled pieces with equal cross-sectional areas on both sides. If line difference changes during the rolling process, the method of adjusting the inlet guide of this frame is usually adopted to align it with the center line of the hole profile of this frame.

Claims

1. A method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type, characterized in that: The steps include: A. Align the inlet and outlet guides of each stand of each finishing mill, adjust the guide opening to match the size of the rolled piece, and ensure that the roll gaps on both sides of each stand of the finishing mill are consistent; B. After being rolled by the rough rolling mill, the rebar is rolled into a round hole shape by the intermediate rolling mill and then enters the finishing rolling mill along the production line; C. Rebar is rolled in the finishing mill group 13#-18# rolling mills, among which 13# is a flat roll without hole type, 14# is a box-type hole type, 15# is a pre-cut hole type, 16# is a cut hole type, 17# is a flat oval hole type, and 18# is a finished hole type. The rebar is cut by the 16# rolling mill, shaped by the 17# and 18# rolling mills, and then the finished product is output.

2. The method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type according to claim 1, characterized in that: The line segments and arc segments of the hole profile are tangentially connected.

3. The method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type according to claim 1 or 2, characterized in that: In the step C, the fullness of the width of the rolled piece in the 15# pre-cutting frame is not less than 98% compared with the width of the hole pattern of the frame, and the fullness is not higher than 100%.

4. The method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type according to claim 3, characterized in that: For the 15# rolling mill, according to the actual width of the rolled product in this stand, the hole parameters of the arc segment radius R and the arc center distance L are designed. When other hole parameters remain unchanged, the hole width B is appropriately reduced to increase the filling degree of the rolled product in the hole to meet the requirements.

5. The method for stabilizing the difference between two cutting rolling lines by pre-cutting pass type according to claim 4, characterized in that: The reduction value of the cross-sectional area of ​​the 15# rolling mill hole is not greater than 3%.

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