A 12-screw four-cut rolling production process
By adopting an 18-stand mill grouping and a specific pass design in the 12-screw four-slit rolling process, combined with micro-tension rolling and a rolling guide mechanism, the problems of high failure rate and large negative tolerance line difference in the slit production were solved, and a stable and efficient rolling process was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANGCHUN NEW STEEL CO LTD
- Filing Date
- 2023-08-03
- Publication Date
- 2026-05-29
AI Technical Summary
The problem of high failure rate and high negative tolerance line difference in the 12-screw four-slit rolling production.
The rolling mill consists of 18 stands divided into three units: roughing mill, intermediate mill, and finishing mill. The specific mill layout and pass design include non-perforated flat rolls, vertical box passes, pre-cut passes, and cut passes. It combines micro-tension rolling and looper use, and especially in the finishing mill unit, a rolling guide mechanism is set up.
It improves the stability of rolled parts, reduces production failure rate, reduces negative tolerance line difference, improves production efficiency and finished product quality, and reduces the labor intensity of operators.
Smart Images
Figure CN117358749B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of profile steel rolling technology, specifically a 12-screw four-slit rolling production process. Background Technology
[0002] Slitting rolling refers to a rolling process in which a single rolled piece is longitudinally cut into two (or more) rolled pieces on a section steel rolling mill using special roll passes and guide devices, thereby producing two (or more) finished rolled products. Based on whether auxiliary devices are used in the slitting process, it is divided into two main categories: roll pass slitting rolling and tool slitting rolling. Based on the number of rolled pieces produced, it is further classified as double-cut, triple-cut, quadruple-cut, quintuple-cut, etc.
[0003] Compared to traditional rolling processes, the main advantage of slitting rolling is that it further improves production efficiency. In terms of production efficiency, four cuts of 12-screw rebar generally have a significant advantage over two or three cuts of 12-screw rebar. However, as the number of cuts increases, the difficulty of production control will increase significantly, the failure rate of slitting production will be high, and the negative tolerance line difference will also be magnified many times over, making it difficult to guarantee the quality of the cut products. Summary of the Invention
[0004] The purpose of this invention is to provide a 12-screw four-slit rolling production process to solve the problems of high failure rate and high negative tolerance line difference in the slit production mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a 12-screw four-slit rolling production process, wherein a 155 square billet passes through 18 rolling mills in sequence, and the 18 rolling mills are divided into three units: roughing mill, intermediate mill, and finishing mill;
[0006] 1) The roughing mill rolls 6 passes, namely K18-K13; the intermediate mill rolls 6 passes, namely K12-K7; and the finishing mill rolls 6 passes, namely K6-K1.
[0007] 2) The roughing mills K18-K13 use 550 short stress line mills with alternating horizontal and vertical mill arrangements and use non-perforated flat rolls for rolling. The intermediate mills K12-K7 use 420 short stress line mills with alternating horizontal and vertical mill arrangements and use alternating elliptical and round-perforated rolls for rolling. The finishing mills K6-K1 use 350 short stress line mills. K5 is vertically arranged, and the rest are horizontally arranged. The pass types of K6-K1 are non-perforated flat rolls, vertical box pass type, pre-cut pass type, cut pass type, elliptical pass type, and finished pass type, respectively.
[0008] Preferably, the top edge radius of the vertical box end of the finishing mill K5 is R1=3mm, the inner width of the end slot is b=15mm, the outer width is B=19.58mm, the end height is H1=58.5mm, and the roll gap is S1=6mm.
[0009] Preferably, in the finishing mill K4 pre-splitting line 1 and 4 outer circular hole type sidewall oblique angle β=35°, outer circle splitting wedge angle α=44°, arc radius R2=7.3mm, hole type height H2=15.2mm, roll gap S2=3mm; in the middle line 2 and 3 hole type splitting wedge angle θ=43°, middle splitting wedge angle γ=85°, arc radius R3=7mm, hole type height H3=15mm, splitting wedge angle radius R4=1.4mm, splitting wedge angle radius R5=2mm, roll gap S3=5.5mm.
[0010] Preferably, the center distance between the two middle holes of the K4 pre-splitting mill is A1=16.1mm, the groove width of the two middle holes is A2=32.2mm, the center distance between the two side holes is A3=48.9mm, and the groove width of the two side holes is A4=64.9mm.
[0011] Preferably, in the finishing mill K3, the oblique angle of the outer circular die sidewall is δ=44°, the outer circular die wedge angle is ε=28°, the arc radius is R6=7mm, the die height is H4=14mm, the roll gap is S4=3mm, the middle 2nd and 3rd line die wedge angle is λ=27°, the middle die wedge angle is ω=55°, the arc radius is R7=6.9mm, the die height is H5=14mm, the wedge radius is R8=0.8mm, the wedge radius is R9=5mm, and the roll gap is S5=0.8mm.
[0012] Preferably, the center distance between the two middle holes of the finishing mill K3 is B1=16.2mm, the groove width of the two middle holes is B2=32.4mm, the center distance between the two side holes is B3=48.8mm, and the groove width of the two side holes is B4=65.32mm.
[0013] Preferably, the elliptical wedge radius of the K2 elliptical pass of the finishing mill unit is R10=2mm, the arc radius is R11=6.9mm, the roll gap is S6=23mm, the pass height is H6=9.7mm, and the slot width is C1=19.28mm.
[0014] Preferably, the finished pass of the finishing mill K1 has a circular wedge radius R12=0.75mm, an arc diameter φ1=11.5mm, a roll gap S7=1.6mm, a pass height H7=11.5mm, and the width of the slot is equal to the pass height.
[0015] Preferably, both the roughing and intermediate rolling mills employ micro-tension rolling, and each mill in the finishing mill is equipped with loopers, wherein there are three single-channel loopers between K6 and K3; and two multi-line cutting loopers between K3 and K1, with the number of looper channels matching the number of cutting lines.
[0016] Preferably, the inlets of the finishing mill K6 and K2 are equipped with rolling guide mechanisms.
[0017] Compared with the prior art, the beneficial effects of the present invention are:
[0018] 1. The vertical box pass has a small deformation amount, and the rolled piece is processed into a concave rolled piece with a smaller size in the middle than on both sides. This solves the problem that the temperature drop of the cutting lines 1 and 4 is greater than that of the middle lines 2 and 3 due to the long distance between the intermediate and finishing mills; it also solves the problem of poor centering of the rolled piece head when entering the pre-cutting pass.
[0019] 2. The pre-cutting holes 1 and 4 of the K4 rolling mill are 0.2mm higher than the middle holes 2 and 3. The wedge angles of the two middle holes are symmetrical. The difference between the outer circle cutting wedge angle and the middle cutting wedge angle is 7°-8°. The radius of the cutting wedge angle is 1.4mm. The center distance of the four holes is 16.1mm. This achieves wear resistance and uniform wear of the pre-cutting hole wedge angles. The material distribution of the four rolled pieces is uniform, and the difference between the four lines is small. This improves the stability of the rolled pieces during the cutting rolling process and reduces the production failure rate.
[0020] 3. The center distance B1 of the two holes in the K3 split is 0.1mm larger than the center distance A1 of the two holes in the pre-cutting. The groove width B2 of the two holes in the middle and the groove width B4 of the two side holes are both larger than the corresponding widths of the pre-splitting. In addition, the height of the hole types of the middle 2 and 3 lines is consistent with that of the hole types of the outer 1 and 4 lines, so that the pre-cut blanks can enter the splitting holes accurately and stably. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the K12 hole structure of the present invention;
[0022] Figure 2 This is a schematic diagram of the K11 hole structure of the present invention;
[0023] Figure 3 This is a schematic diagram of the K10 hole structure of the present invention;
[0024] Figure 4 This is a schematic diagram of the K9 hole structure of the present invention;
[0025] Figure 5 This is a schematic diagram of the K8 hole structure of the present invention;
[0026] Figure 6 This is a schematic diagram of the K7 hole structure of the present invention;
[0027] Figure 7 This is a schematic diagram of the K5 vertical box hole structure of the present invention;
[0028] Figure 8 This is a schematic diagram of the K4 pre-cut hole structure of the present invention;
[0029] Figure 9 This is a schematic diagram of the K3 segmented hole structure of the present invention;
[0030] Figure 10 This is a schematic diagram of the K2 elliptical hole structure of the present invention;
[0031] Figure 11 This is a schematic diagram of the hole structure of the K1 finished product of the present invention. Detailed Implementation
[0032] The technical solutions of 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.
[0033] Please see Figure 1-11 A 12-screw four-slit rolling production process involves first heating a 155mm square billet using conventional rebar heating technology, with an initial rolling temperature ≥950℃ and a billet temperature difference ≤30℃ to ensure billet temperature uniformity. The 155mm square billet then passes through 18 rolling mills, which are divided into roughing, intermediate, and finishing mills.
[0034] 1) The roughing mill rolls 6 passes, with the pass numbers or mill numbers being K18-K13; the intermediate mill rolls 6 passes, with the pass numbers or mill numbers being K12-K7; and the finishing mill rolls 6 passes, with the pass numbers or mill numbers being K6-K1.
[0035] 2) The roughing mill units K18-K13 employ a 550 short-stress line mill, with alternating horizontal and vertical mill layouts, and use non-perforated flat rolls. Please refer to [link / reference]. Figure 1-6 The intermediate rolling mills K12-K7 employ 420 short-stress-line mills, with alternating horizontal and vertical mill layouts, and use alternating elliptical and circular-drill rolls. Please refer to [link / reference needed]. Figure 7-11 The finishing mills K6-K1 adopt 350 short stress line mills, K5 is vertically arranged, and the rest are horizontally arranged. The pass types of K6-K1 are flat roll without pass type, vertical box pass type, pre-cut pass type, cut pass type, elliptical pass type and finished pass type, respectively.
[0036] The pass patterns for roughing and intermediate rolling are the same as those for other specifications; see details below. Figure 1-6 It should be noted that the cutting edges of the K4 pre-cutting and K3 cutting holes should overlap, and the cross-sectional area of each hole should be as equal as possible to obtain a smaller finished product line difference.
[0037] The materials used for the rolling mill rolls are as follows: the roughing and intermediate rolling rolls are made of medium-nickel chromium molybdenum indefinite chilled spherical cast iron; the roll configurations for each pass of the finishing rolling mill are as follows: K6 is high-speed steel, K5 is bainitic steel, K4 is high-speed steel, K3 is alloy nitride (balancing toughness and wear resistance, preventing excessive hardness and chipping), K2 is tungsten carbide, and K1 is tungsten carbide.
[0038] The 155 square billet is rolled by the non-perforated flat rolls of the roughing mill and then enters the intermediate rolling mills K12-K7 for rolling. The pass profiles of the intermediate rolling mills K12-K7 are as follows: Please refer to [link / reference]. Figure 1 The K12 elliptical pass of the intermediate rolling mill has an elliptical wedge radius of R13=10mm, an arc radius of R14=61.6mm, a roll gap of S8=10mm, a pass height of H8=60mm, and a slot width of C2=99.1mm.
[0039] Please see Figure 2 The K11 round hole wedge radius of the intermediate rolling mill is R15=5mm, the arc radius is R16=33.25mm, the roll gap is S9=9.5mm, the hole height is H9=66.5mm, and the hole groove width is C3=71.4mm.
[0040] Please see Figure 3 The K10 elliptical pass of the intermediate rolling mill has an elliptical wedge radius of R17=8mm, an arc radius of R18=59.1mm, a roll gap of S10=7mm, a pass height of H10=60mm, and a slot width of C4=86.83mm.
[0041] Please see Figure 4 The K9 round hole wedge radius of the intermediate rolling mill is R19=5mm, the outer arc angle is ψ=120°, the arc diameter is φ2=53mm, the roll gap is S11=7mm, the hole height is H11=53mm, and the hole groove width is C5=57.1577mm.
[0042] Please see Figure 5 The K8 elliptical pass of the intermediate rolling mill has an angular radius of R20=8mm, an arc radius of R21=62.2mm, a roll gap of S12=8mm, and a pass height of H12=33mm.
[0043] Please see Figure 6 The K7 round hole sidewall of the intermediate rolling mill has an arc radius of R22=6mm on each side, an arc radius of R23=15mm, a roll gap of S13=8mm, a hole height of H13=50mm, and a groove width of C6=36.52mm.
[0044] The semi-finished products rolled by the intermediate rolling mill enter the finishing mills K6-K1 for further rolling. The pass configuration of the finishing mills K6-K1 is as follows: Finishing mill K6 uses flat roll rolling without passes. Please refer to [link / reference]. Figure 7The K5 vertical box pass of the finishing mill has a side wall radius of R1=3mm, an inner width b=15mm, an outer width B=19.58mm, a pass height H1=58.5mm, and a roll gap S1=6mm. Due to the small deformation of the vertical box pass, the rolled piece is machined into a concave shape with a smaller central dimension than the two sides. This solves the problem of the long distance between the intermediate and finishing mills, resulting in a larger temperature drop at cutting lines 1 and 4 compared to the central lines 2 and 3. It also solves the problem of poor alignment at the head of the rolled piece entering the pre-cutting pass, causing head bending and steel accumulation at the finished product rack exit.
[0045] Please see Figure 8 For the finishing mill K4 pre-splitting lines 1 and 4, the side wall bevel angle β = 35°, the outer circle slitting wedge angle α = 44°, the arc radius R2 = 7.3mm, the pass height H2 = 15.2mm, and the roll gap S2 = 3mm. For the middle lines 2 and 3, the slitting wedge angle θ = 43°, the middle slitting wedge angle γ = 85°, the arc radius R3 = 7mm, the pass height H3 = 15mm, the slitting wedge radius R4 = 1.4mm, the slitting wedge radius R5 = 2mm, and the roll gap S3 = 5.5mm.
[0046] Preferably, the center distance between the two middle holes in the K4 pre-splitting of the finishing mill is A1=16.1mm, the groove width of the two middle holes is A2=32.2mm, the center distance between the two side holes is A3=48.9mm, and the groove width of the two side holes is A4=64.9mm.
[0047] The pre-cutting hole heights of the K4 mill in the finishing mill unit are 0.2mm higher than those of the middle holes 2 and 3. The wedge angles of the two middle holes are symmetrical. The difference between the outer circle cutting wedge angle and the middle cutting wedge angle is 7-8°. The radius of the cutting wedge angle is 1.4mm. The center distance of the four holes is 16.1mm. This achieves wear resistance and uniform wear of the pre-cutting hole wedge angles. The material distribution of the four rolled pieces is uniform, and the difference between the four lines is small. This improves the stability of the rolled pieces during the cutting rolling process and reduces the production failure rate.
[0048] Please see Figure 9 The K3 finishing mill has a sidewall bevel angle δ=44° for the outer circular die, an outer circular die wedge angle ε=28°, an arc radius R6=7mm, a die height H4=14mm, and a roll gap S4=3mm. The middle 2nd and 3rd line die wedge angles λ=27°, the middle die wedge angle ω=55°, an arc radius R7=6.9mm, a die height H5=14mm, a wedge radius R8=0.8mm, a wedge radius R9=5mm, and a roll gap S5=0.8mm.
[0049] Preferably, the center distance between the two middle holes of the finishing mill K3 is B1=16.2mm, the groove width of the two middle holes is B2=32.4mm, the center distance between the two side holes is B3=48.8mm, and the groove width of the two side holes is B4=65.32mm.
[0050] In the K3 slitting process of the finishing mill, the sum of the outer circle slitting wedge angle ε and the slitting wedge angle λ is equal to the middle slitting wedge angle. The center distance B1 of the two middle holes is 0.1 mm larger than the center distance A1 of the two pre-cut middle holes. The groove width B2 of the two middle holes and the groove width B4 of the two side holes are both larger than the corresponding widths of the pre-slitting. In addition, the height of the middle 2 and 3 line hole types is consistent with that of the outer 1 and 4 line hole types, so that the pre-cut billet can accurately and stably enter the slitting hole type.
[0051] Please see Figure 10 The elliptical wedge radius of the K2 elliptical pass of the finishing mill is R10=2mm, the arc radius is R11=6.9mm, the roll gap is S6=23mm, the pass height is H6=9.7mm, and the slot width is C1=19.28mm.
[0052] Please see Figure 11 The finished product pass of the finishing mill K1 has a circular wedge radius R12=0.75mm, an arc diameter φ1=11.5mm, a roll gap S7=1.6mm, a pass height H7=11.5mm, and the width of the slot is equal to the pass height.
[0053] Preferably, both the roughing and intermediate rolling mills employ micro-tension rolling, and each mill in the finishing mill is equipped with loopers, wherein there are three single-channel loopers between K6 and K3; and two multi-line cutting loopers between K3 and K1, with the number of looper channels matching the number of cutting lines.
[0054] In addition, the guides for each mill stand are configured in the same way as those in the conventional cutting process, using sliding guides. The difference is that the K6 and K2 entrances of the finishing mill are equipped with rolling guide mechanisms to strengthen the clamping of the rolled piece by the guides, eliminate a series of accidents caused by unstable clamping of the rolled piece and uneven wear of the rolling groove, and reduce the production failure rate. At the same time, it also promotes the increase of steel throughput in the rolling groove to a certain extent.
[0055] In summary, this invention can be directly implemented under the equipment capacity conditions of 12-screw three-splitting. After the modification, the output is higher than that of three-splitting, which not only reduces production costs and improves production efficiency, but also reduces the labor intensity of operators. Moreover, the average negative tolerance line difference of the finishing mill splitting is low, which provides the possibility of low negative tolerance rolling. It effectively eliminates faults such as steel sticking to the splitting blade and the top exit of the finished product.
[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A 12-screw four-section rolling production process, wherein a 155 square billet passes sequentially through 18 rolling mills, the 18 rolling mills being divided into three units: roughing mill, intermediate mill, and finishing mill, characterized in that: 1) The roughing mill rolls 6 passes, namely K18-K13; the intermediate mill rolls 6 passes, namely K12-K7; and the finishing mill rolls 6 passes, namely K6-K1. 2) The roughing mills K18-K13 use 550 short stress line mills with alternating horizontal and vertical mill arrangements and use non-perforated flat rolls for rolling. The intermediate mills K12-K7 use 420 short stress line mills with alternating horizontal and vertical mill arrangements and use alternating elliptical and round-perforated rolls for rolling. The finishing mills K6-K1 use 350 short stress line mills. K5 is vertically arranged, and the rest are horizontally arranged. The pass types of K6-K1 are non-perforated flat rolls, vertical box pass type, pre-cut pass type, cut pass type, elliptical pass type, and finished pass type, respectively. The K5 vertical box of the finishing mill has a side radius of curvature R1=3mm at the top of the side wall of the pass, an inner width b=15mm, an outer width B=19.58mm, a pass height H1=58.5mm, and a roll gap S1=6mm. The K4 finishing mill pre-slit lines 1 and 4 have an outer circular die sidewall bevel angle β=35°, an outer circular slitting wedge angle α=44°, an arc radius R2=7.3mm, a die height H2=15.2mm, and a roll gap S2=3mm. The middle lines 2 and 3 have a die slitting wedge angle θ=43°, a middle die slitting wedge angle γ=85°, an arc radius R3=7mm, a die height H3=15mm, a wedge angle radius R4=1.4mm, a wedge angle radius R5=2mm, and a roll gap S3=5.5mm. The K3 finishing mill has the following characteristics: outer circular die sidewall bevel angle δ=44°, outer circular die wedge angle ε=28°, arc radius R6=7mm, die height H4=14mm, roll gap S4=3mm; middle 2 and 3 line die wedge angle λ=27°, middle die wedge angle ω=55°, arc radius R7=6.9mm, die height H5=14mm, die wedge radius R8=0.8mm, die wedge radius R9=5mm, roll gap S5=0.8mm. The elliptical wedge radius of the K2 elliptical pass of the finishing mill unit is R10=2mm, the arc radius is R11=6.9mm, the roll gap is S6=23mm, the pass height is H6=9.7mm, and the slot width is C1=19.28mm. The finished pass of the finishing mill K1 has a circular wedge radius R12=0.75mm, an arc diameter φ1=11.5mm, a roll gap S7=1.6mm, a pass height H7=11.5mm, and the width of the slot is equal to the pass height.
2. The 12-screw four-slit rolling production process according to claim 1, characterized in that: The center distance between the two middle holes in the K4 pre-splitting mill of the finishing mill is A1=16.1mm, the groove width of the two middle holes is A2=32.2mm, the center distance between the two side holes is A3=48.9mm, and the groove width of the two side holes is A4=64.9mm.
3. The 12-screw four-slit rolling production process according to claim 1, characterized in that: The center distance between the two middle holes of the finishing mill K3 is B1=16.2mm, the groove width of the two middle holes is B2=32.4mm, the center distance between the two side holes is B3=48.8mm, and the groove width of the two side holes is B4=65.32mm.
4. The 12-screw four-slit rolling production process according to claim 1, characterized in that: Both the roughing and intermediate rolling mills employ micro-tension rolling. The finishing mills are equipped with loopers between each mill, with three single-channel loopers between K6 and K3, and two multi-line split loopers between K3 and K1. The number of looper channels is consistent with the number of splits.
5. The 12-screw four-slit rolling production process according to claim 1, characterized in that: The inlets of the finishing mills K6 and K2 are equipped with rolling guide mechanisms.