A rolling method suitable for Φ16mm three-split hot-rolled ribbed steel

Abstract

The application belongs to the technical field of rolling treatment, and particularly relates to a rolling method suitable for a Φ16mm three-split hot-rolled ribbed steel bar. The rolling raw material is heated through a 180t stepping beam type heating furnace; the rolling raw material is 165*165*12000mm ribbed steel bar; the heated rolling raw material is sequentially subjected to rough rolling, intermediate rolling and finish rolling; the rolling product after rolling is subjected to cold shearing and automatic bundling in real time through a stepping tooth type cooling bed and in combination with a three-split rolling process of the Φ16mm specification screw thread steel, so that the size of the rolling piece entering the finish rolling unit is accurately ensured.

Description

Technical Field

[0001] This invention belongs to the field of rolling processing technology, specifically relating to a rolling method suitable for Φ16mm three-section hot-rolled ribbed steel bars. Background Technology

[0002] Currently, during the rolling process, the two edge slots wear faster than the center slot in the pre-cutting pass, resulting in a smaller inner diameter of the center line, a larger longitudinal rib height, and a smaller weight deviation in the finished product compared to the two edge slots. To ensure that the center line dimensions and weight deviation do not exceed national standards, the overall dimensions of the finished product are increased by 0.1~0.3mm, affecting the yield by about 1%. In other words, the center line dimensions of the Φ16mm three-cutting pass are out of tolerance during the production process, which will affect the product quality.

[0003] Therefore, in view of the above-mentioned technical problems and defects, there is an urgent need to design and develop a rolling method suitable for Φ16mm three-slit hot-rolled ribbed steel bars. Summary of the Invention

[0004] To overcome the shortcomings and difficulties of the existing technology, the purpose of this invention is to provide a rolling method suitable for Φ16mm three-section hot-rolled ribbed steel bars.

[0005] The purpose of this invention is to provide a rolling method suitable for Φ16mm three-section hot-rolled ribbed steel bars.

[0006] The object of this invention is achieved as follows: the method includes the following steps:

[0007] The rolled raw material is heated in a 180t walking beam furnace; wherein the rolled raw material is a 165×165×12000mm ribbed steel bar.

[0008] The heat-treated raw material is subjected to rough rolling, intermediate rolling and finish rolling in sequence;

[0009] By using a walking gear cooling bed and a three-splitting rolling process for Φ16mm threaded steel, the rolled products are cold-sheared and automatically bundled in real time.

[0010] The present invention involves heating the raw material in a 180t walking beam furnace; wherein the raw material is 165×165×12000mm ribbed steel bar; the heated raw material is then subjected to rough rolling, intermediate rolling and finish rolling in sequence; a walking tooth cooling bed is used, combined with a three-splitting rolling process for Φ16mm threaded steel, to perform real-time cold shearing and automatic bundling of the rolled products, thereby ensuring the precise dimensions of the rolled pieces entering the finish mill.

[0011] In other words, the Φ16mm specification rolling mill consists of 17 stands, divided into roughing, intermediate, and finishing mills. After exiting the furnace, the steel billets are transported by conveyor rollers to the first stand of the roughing mill. The billets undergo twist-free rolling in the six alternately arranged horizontal and vertical roughing mill stands (650×3 + 550×3). After the head is removed by the No. 1 flying shear (which can also break the billet in case of an accident), it enters the five alternately arranged horizontal and vertical intermediate mill stands (Φ470×5) for twist-free rolling. Micro-tension control rolling is used within the roughing and intermediate mill stands. The head and tail of the billet are removed by the No. 2 flying shear before entering the finishing mill stand (Φ380×6) for further rolling. Pneumatic vertical loopers are installed between the mill stands in the finishing mill stand, enabling tension-free rolling in this area, thus ensuring the dimensional accuracy of the billets entering the finishing mill. Attached Figure Description

[0012] Figure 1 This is a schematic flowchart of a rolling method for Φ16mm three-section hot-rolled ribbed steel bars according to the present invention.

[0013] Figure 2 This is a schematic flowchart of an embodiment of the rolling method for Φ16mm three-section hot-rolled ribbed steel bars according to the present invention;

[0014] Figure 3 This is a schematic diagram of the original design of the 16H inlet rolling guide roller, which is an embodiment of the rolling method for Φ16mm three-section hot-rolled ribbed steel bars according to the present invention.

[0015] Figure 4 This is a schematic diagram of the current design of the 16H imported rolling guide roller for a rolling method applicable to Φ16mm three-section hot-rolled ribbed steel bars according to the present invention.

[0016] In the diagram: 1 - original guide roller angle; 2 - new guide roller angle. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0018] As attached Figures 1-4 As shown, the present invention provides a rolling method suitable for Φ16mm three-section hot-rolled ribbed steel bars.

[0019] The method includes the following steps:

[0020] S1. The rolled raw material is heated in a 180t walking beam furnace; wherein the rolled raw material is a 165×165×12000mm ribbed steel bar.

[0021] S2. The heat-treated raw material is subjected to rough rolling, intermediate rolling and finish rolling in sequence;

[0022] S3. Using a stepping tooth cooling bed and a three-splitting rolling process for Φ16mm threaded steel, the rolled products are cold-sheared and automatically bundled in real time.

[0023] The heating treatment in the walking beam furnace specifically involves heating to 1000~1060℃ for rolling.

[0024] The step of sequentially performing rough rolling, intermediate rolling, and finish rolling on the heat-treated raw material also includes the following steps:

[0025] S21. Combined with the 6 rolling mills, the heat-treated raw material is subjected to the first micro-tension rolling, and the rolled product is subjected to the first flying shear treatment.

[0026] S22. Combined with the 6 rolling mills, the raw material that has undergone the first flying shear treatment is subjected to a second micro-tension rolling process, and the rolled product is subjected to a second flying shear treatment.

[0027] S23. Combining the six rolling mills and the vertical looper, the raw material for the second flying shear treatment is subjected to tensionless looper rolling, and the rolled product is subjected to a third flying shear treatment.

[0028] The six rolling mills, arranged in combination, perform a second micro-tension rolling on the raw material that has undergone the first flying shear treatment, and then perform a second flying shear treatment on the rolled product. The process also includes:

[0029] S221. After the second micro-tension rolling, the rolled product is subjected to pre-controlled cooling treatment in real time.

[0030] The rolling speed of the tensionless looper rolling is 13.5 m / s. The included angle of the guide rolls in the tensionless looper rolling is 120 degrees.

[0031] The process of using a walking gear cooling bed and a three-splitting rolling process for Φ16mm rebar, which involves real-time cold shearing and automatic bundling of the rolled products, also includes:

[0032] S31. Use at least one 850t cold shear to cold shear the rolled products, and use at least one automatic bundling machine to automatically bundle the cold-sheared rolled products.

[0033] The first micro-tension rolling is a rough rolling of the raw material to be rolled. The second micro-tension rolling is an intermediate rolling of the raw material to be rolled. The tension-free looper rolling is a finish rolling of the raw material to be rolled.

[0034] Specifically, in a specific embodiment of the present invention, the raw material for rolling is 165×165×12000mm, heated to 1000~1060℃ in a 180t walking beam furnace for rolling. There are 18 rolling mills in total, arranged alternately as horizontal and vertical mills (No. 14 is a convertible horizontal / vertical mill), and divided into three units: roughing, intermediate, and finishing mills. Each unit consists of 6 mills. The finishing mill unit has 6 vertical loopers. The rolled workpiece is rolled under low tension in the roughing and intermediate mill units, and under tension-free looper rolling in the finishing mill unit to improve the dimensional accuracy of the product. Φ16mm rebar uses a three-slit rolling process, and the mill pass system adopts an elliptical-circular pass system. The entire rolling mill is a high-rigidity, short-stress-line mill, with the highest rolling speed of the finishing mill unit being 13.5m / s. The rolling line is also equipped with three flying shears, and the finishing area has a walking tooth cooling bed, an 850t cold shear and an automatic baler.

[0035] Preferably, the original finishing mill pass system uses no-hole-box-pre-splitting-splitting-K2-K1, and the redesigned pass system retains the 13H14V17H18H pass types, with only the 15H16H pass type changing.

[0036] The inlet and outlet guide assemblies of the finishing mill retain the original pass type guides. The 16H inlet guide rollers were redesigned based on the new pass type, and the included angle of the original 16H inlet guide rollers was changed from 110° angle 1 to 120° angle 2.

[0037] The present invention relates to the following die patterns and guides: A die pattern system is used to redesign the 15H and 16H die patterns. Based on the original die patterns, the width of the 15H die pattern is reduced from 68.7mm to 65.05mm, and the height of the 15H edge line is increased from 20.5mm to 21.6mm. The width of the 16H die pattern is reduced from 68mm to 66.73mm, the height is reduced from 19.6mm to 19.4mm, the die pattern radius is reduced from 9.6mm at the center line and 9.8mm at the edge line to 9.5mm at all three lines, and the roll gap value is reduced from 1.0mm to 0.8mm.

[0038] The 16H imported guide roller was redesigned based on the shape of the 15H pass. The included angle of the guide roller was optimized from the original 110° to 120° to make it consistent with the size and shape of the rolled piece and ensure good performance.

[0039] The rolling method of the present invention

[0040] (1) Rough rolling process parameters: The rough rolling mill rolls 6 times, and the pass distribution is no hole - no hole - ellipse - circle - ellipse - circle. The material size did not change before and after the improvement.

[0041] Table 1. Rolling parameters for roughing roll pass

[0042]

[0043] (2) Table of intermediate rolling process parameters

[0044] The intermediate mill rolls 5 passes, and the pass distribution is ellipse-circle-ellipse-circle-no-pass. After the improvement, the pass shape remains unchanged, and the material size of 7H-11H is adjusted (see Table 2 and Table 3 for details).

[0045] Table 2 shows the rolling parameters for the original rolling pass.

[0046]

[0047] Table 3 shows the rolling parameters of the improved rolling pass.

[0048]

[0049] (3) Comparison of finishing rolling process parameters before and after improvement, and changes in roll gap values ​​of 13H-16H material shape, see Table 4 and Table 5 for details.

[0050] Table 4 Rolling parameters for the original finishing pass

[0051]

[0052] Table 5. Rolling parameters after finishing rolling improvement

[0053]

[0054] This invention mainly achieves small dimensional deviation of Φ16mm finished products by optimizing the design of the 15H16H pass system and guide dimensions of the finishing mill, optimizing the material shape dimensions of 13H14V, and maintaining the original process of 17H18H. It solves the problem of small center dimensions and difficulty in adjustment in the original pass system, and has good production application effect and promotion application value.

[0055] The specific implementation steps of this invention are as follows:

[0056] 1. The mill and roll pass arrangement remain unchanged. The newly designed 15H16H roll pass replaces the original 15H16H roll pass. The material size 13H~16H has been optimized (see Table 1 and Table 2 for details).

[0057] 2. The dimensions of the 16H imported guide rollers were designed, while the guide body retained the original design.

[0058] 3. During the rolling process, the opening degree of the inlet guide of the 14V-17H rolling mill is finely adjusted according to the size of the rolled piece to achieve the most suitable and stable rolling operation.

[0059] Example 1

[0060] 1. The chemical composition of Φ16mm HRB500E is: C content 0.21%~0.25%, Si content 0.45%~0.51%, Mn content 1.46%~1.55%, S content 0.017%~0.029%, and P content 0.015%~0.031%. The chemical composition of Φ16mm HRB400E is: C content 0.21%~0.25%, Si content 0.45%~0.50%, Mn content 1.36%~1.46%, S content 0.009%~0.020%, and P content 0.017%~0.022%.

[0061] Table 6 Chemical composition of Φ16mm specification rolled product

[0062]

[0063] 2. The improved finished product has an inner diameter deviation of 0.10mm. The height of the transverse ribs, the height of the longitudinal ribs, the rib spacing, and the gap at the end of the transverse ribs all meet the national standard requirements (see Tables 7 and 8 for details). Three samples were taken from each furnace number to test the weight deviation value. The difference in weight deviation value between the dividing center line and the edge line is within 0.4%. The weight deviation can be controlled within the range of -3.7% to -4.5%. The fluctuation range is reduced, which reduces the quality risk of weight deviation.

[0064]

[0065] Table 8 Weight Deviation Detection Results

[0066]

[0067] 3. Improved mechanical properties: Φ16mm HRB500E: Yield strength 520~550MPa, tensile strength 675~710MPa, elongation 18%~24%, strength-to-yield ratio 1.28~1.30, total elongation 11.4%~16.4%, yield-to-yield ratio 1.04~1.10. Φ16mm HRB400E: Yield strength 415~440MPa, tensile strength 585~605MPa, elongation 20%~26%, strength-to-yield ratio 1.38~1.43, total elongation 13.0%~16.1%, yield-to-yield ratio 1.04~1.10. Mechanical properties meet national standards.

[0068] Table 9 Mechanical properties of Φ16mm specification

[0069] .

Claims

1. A rolling method suitable for Φ16mm three-section hot-rolled ribbed steel bars, characterized in that, Includes the following steps: S1. The rolled raw material is heated in a 180t walking beam furnace. The rolled raw material is a 165×165×12000mm square billet. S2. The heat-treated raw material is subjected to rough rolling, intermediate rolling, and finish rolling processes in sequence, including: S21. Combined with the six roughing mills, the heat-treated raw material is subjected to the first micro-tension rolling, and the rolled product is subjected to the first flying shear treatment. S22. Combined with the five intermediate rolling mills, the raw material that has undergone the first flying shear treatment is subjected to a second micro-tension rolling process, and the rolled product is subjected to a second flying shear treatment. It also includes real-time pre-controlled cooling treatment of the rolled product after the second micro-tension rolling. S23. Combining the six finishing mills and the vertical looper, the raw material subjected to the second flying shear treatment is subjected to tensionless looper rolling, and the rolled product is subjected to a third flying shear treatment; the material shape dimensions of finishing mills 13H and 14V are optimized, with the material height and width of 13H adjusted from 22mm and 69mm to 21mm and 70mm, and the material height of 14V adjusted from 57.5mm to 56mm; the pass shape and guide dimensions of finishing mills 15H and 16H are optimized, with the pass width of 15H increased from 68.7mm. The diameter (m) is reduced to 65.05 mm, the edge height is increased from 20.5 mm to 21.6 mm, the width of the 16H pass is reduced from 68 mm to 66.73 mm, the pass height is reduced from 19.6 mm to 19.4 mm, the pass radius is reduced from the original centerline 9.6 mm and edgeline 9.8 mm to 9.5 mm across all three lines, the roll gap is reduced from 1.0 mm to 0.8 mm, and the guide roll angle of the 16H inlet guide of the finishing mill is adjusted from 110° to 120°; the rolling speed of the tensionless looper rolling is 13.5 m / s. S3. Using a stepping tooth cooling bed and a three-splitting rolling process for Φ16mm threaded steel, the rolled products are cold-sheared and automatically bundled in real time.

2. The rolling method according to claim 1, characterized in that, The S1 medium walking beam furnace heating treatment specifically involves heating to 1000~1060℃ for rolling.

3. The rolling method according to claim 1, characterized in that, S3 also includes: using at least one 850t cold shear to cold shear the rolled products, and using at least one automatic bundling machine to automatically bundle the cold-sheared rolled products.

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