Method for producing c-shaped steel for bridge support and c-shaped steel for bridge support

Abstract

This invention discloses a method for producing C-shaped steel for bridge bearings. The method includes: providing a shaped cast billet and heating it; performing descaling and initial rolling, wherein a multi-pass rolling process is performed using a specialized die system with asymmetrical top and bottom and symmetrical left and right sides; after removing the ends of the rolled piece, universal rolling is performed, and through an optimized UF die, bosses are formed on both sides of the rolled piece legs; finally, the finished product is obtained through cooling and straightening. The hot-rolled C-shaped steel produced by this method has precise dimensions and excellent performance, directly meeting the near-net-shape requirements of the bearing plate on bridge bearings, significantly reducing subsequent processing, effectively lowering production costs, and improving production efficiency. This invention also discloses a C-shaped steel for bridge bearings.

Description

Technical Field

[0001] This invention belongs to the field of steel production technology. Specifically, this invention relates to a method for producing C-shaped steel for bridge bearings and the C-shaped steel for bridge bearings. Background Technology

[0002] Bridge bearings are crucial structural components connecting the superstructure and substructure of a bridge. Located between the bridge deck and the bearing pad, they are vital force transmission devices. Currently, the bearing plates for railway and highway bridge bearings in China are mainly machined using ingot casting. However, this method of machining bearings suffers from drawbacks such as large machining volume and high processing costs.

[0003] Chinese Patent Publication No. CN117531857A discloses a water spraying device for improving the temperature difference across the cross-section of hot-rolled strip steel. The device includes two sets of spray heads fixed to a guide plate at the finishing mill inlet side, both sets positioned above the hot-rolled strip steel. Each spray head includes a nozzle base and a nozzle. The nozzle base is fixed to the nozzle head base by fixing bolts and clamping blocks. One end of the nozzle base is connected to a water pipe connector, and the other end is connected to the nozzle. The nozzles in both sets of spray heads spray water in a direction within 80-200mm of both sides of the hot-rolled strip steel. The nozzle base and nozzle are provided with spray holes.

[0004] Chinese Patent CN106623445A discloses a laminar flow cooling system and method for controlling double-sided ripples in hot-rolled strip steel. By changing the nozzle orifice diameter of the two side sections of the cooling manifold in a linear manner within a certain cooling section, the distribution of cooling water at the side can be altered. This effectively reduces the temperature drop at the edge of the strip steel during the laminar cooling process, adapts to changes in product width, improves the transverse temperature uniformity and straightness of the strip steel, and enhances the quality of the strip shape.

[0005] Chinese Patent No. CN205244814U discloses a hot-rolled channel steel for tunnels, which is a U-shaped part including two side flanges and a middle web. The distance between the outer sides of the two side flanges of the channel steel is 150±2.0mm, the thickness of the two side flanges is 12±1.0mm, the length of the flanges is 90±1.0m, the thickness d of the web is 6.5±0.5mm, and the bottom of the outer side of the flanges and the area between the web and the two side flanges are all smooth arc transitions.

[0006] Chinese patent CN117165846A discloses a hot-rolled C-shaped steel with equal wall thickness and its manufacturing process. The hot-rolled C-shaped steel includes an integrally hot-rolled web and two flanges. The two flanges are located at opposite ends of the web and form a C-shaped structure with it. The junction between the two flanges and the web is a circular arc transition section. The cross-sectional thickness of the web, the two circular arc transition sections, and the two flanges are equal. The cross-sectional length of the flanges ranges from 125mm to 500mm, the cross-sectional length of the web ranges from 500mm to 1000mm, and the cross-sectional thickness of the web ranges from 20mm to 50mm.

[0007] Chinese patent CN206112485U discloses a hot-rolled C-shaped channel steel for earthquake resistance. The C-shaped channel steel includes a channel steel body with a dovetail-shaped inner bend and an anti-slip structure at the dovetail. The width of the C-shaped channel steel body is 41mm; the thickest part of the dovetail is 6mm, and other parts are no less than 4mm. The dovetail shape of the inner bend of the C-shaped channel steel increases horizontal shear resistance, with a single-point lateral shear resistance reaching 14000N. The earthquake-resistant pipe clamp for fixing the pipeline has two T-bolts, and the single-pipe shear resistance of the channel opening can reach 28000N, fully meeting the requirements for resisting longitudinal seismic forces on pipelines below DN350. The hot-rolled C-shaped channel steel has a toothed dovetail, which, through the earthquake-resistant pipe clamp, can resist lateral seismic forces on the pipeline. With a width of 41mm, it can be double-jointed back-to-back with existing cold-formed channel steel, increasing the load-bearing capacity of the channel steel, and it is compatible with all existing channel steel accessories for supports and hangers.

[0008] Chinese Patent No. CN214653399U discloses a hot-rolled C-shaped steel for forklift masts. The hot-rolled C-shaped steel for forklift masts includes: a web, a first flange, and a second flange. The hot-rolled C-shaped steel for forklift masts also includes: a boss; the first flange and the second flange are located at both ends of the lower surface of the web, forming a C-shaped structure with the web; the boss is located at the connection between the lower surface of the web and the left side of the second flange. The web thickness is 10-13 mm, and the width is 170-176 mm; the first flange thickness is 23-27 mm, and the width is 33-37 mm; the second flange thickness is 25-30 mm, and the width is 33-37 mm; the boss width is 20-30 mm, and the height is 3-5 mm.

[0009] In summary, although hot-rolled steel sections with C-shaped or U-shaped cross-sections are currently used in tunnel support, seismic structures, and special engineering vehicles, their requirements for cross-sectional shape, dimensional tolerances, and mechanical properties differ significantly from those for bridge bearing steel. Existing technologies do not disclose the die structure and supporting production process for hot-rolled C-shaped steel suitable for bridge bearings, making it impossible to directly meet the production requirements of conventional C-shaped steel production lines for bridge bearings.

[0010] A method for producing C-shaped steel for bridge bearings is provided, particularly concerning how to meet the production requirements of C-shaped steel for bridge bearings and improve processing efficiency. Summary of the Invention

[0011] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a method for producing C-shaped steel for bridge bearings, with the purpose of meeting the production requirements of C-shaped steel for bridge bearings and improving processing efficiency.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is: a method for producing C-shaped steel for bridge bearings, comprising the following steps:

[0013] S1. Provide irregularly shaped cast billets that conform to the predetermined chemical composition;

[0014] S2. Heat the irregularly shaped billet to austenitize its microstructure;

[0015] S3. Dephosphorize the heated billet;

[0016] S4. The dephosphorized billet is rolled in a two-roll rolling mill for multiple passes. The multiple passes are rolled in a pass system with at least three passes. The pass system is designed to be asymmetrical from top to bottom and symmetrical from left to right.

[0017] S5. Trim the ends of the rolled piece after the billet rolling process.

[0018] S6. Universal rolling is performed on the rolled piece after the end is cut: a universal rolling mill is used for rolling. The universal rolling mill includes a UF die. The lower horizontal roll of the UF die is provided with a boss, and the vertical roll of the UF die is provided with a boss, so that the boss of the rolled piece after rolling is located on both sides of its leg.

[0019] S7. Cool the rolled piece after universal rolling;

[0020] S8. Straighten the cooled rolled piece to obtain the finished product.

[0021] The chemical composition of the irregularly shaped billet, by mass percentage, is as follows: C: 0.16-0.20, Si: 0.20-0.35, Mn: 1.31-1.45, P: ≤0.030, S: ≤0.020, V: 0.025-0.035, with the remainder being Fe and unavoidable impurities.

[0022] In step S2, the heating temperature is 1200℃~1280℃, and the furnace time is 120min~280min.

[0023] In step S4, the hole pattern system includes hole patterns K1, K2 and K3 arranged sequentially.

[0024] The structural parameters of the K1 hole type are as follows: the upper waist width a1 and the lower waist width a2 are equal, which is 345-545mm; the upper groove bottom width b1 and the lower groove bottom width b2 are equal, which is 78-102mm; the upper groove opening width c1 and the lower groove opening width c2 are equal, which is 128-152mm; the upper groove depth d1 is 94-106mm, and the lower groove depth d2 is 114-136mm; the upper fillet R1 is equal to the lower fillet R2, which is 50-60mm.

[0025] The structural parameters of the K2 hole type are as follows: upper waist width a1 is 320-520mm, lower waist width a2 is 360-560mm; upper groove bottom width b1 is 110-130mm, lower groove bottom width b2 is 100-120mm; upper groove opening width c1 is 160-180mm, lower groove opening width c2 is 140-160mm; upper groove depth d1 is 25-45mm, lower groove depth d2 is 75-95mm; upper fillet R1 is 60-80mm, lower fillet R2 is 30-40mm.

[0026] The structural parameters of the K3 hole type are as follows: upper waist width a1 is 330-530mm, lower waist width a2 is 380-580mm; upper groove bottom width b1 is 131-141mm, lower groove bottom width b2 is 125-135mm; upper groove opening width c1 is 192-202mm, lower groove opening width c2 is 159-179mm; upper groove depth d1 is 65-85mm, lower groove depth d2 is 60-80mm; upper fillet radius R1 is 80-100mm, lower fillet radius R2 is 20-30mm.

[0027] In step S5, a hot saw is used to remove the irregular portion at the end of the rolled piece after the initial rolling process.

[0028] In step S6, the structural parameters of the UF die are as follows: the width w1 of the upper horizontal roller is 560-810mm, the width w2 of the lower horizontal roller boss is 356-606mm, the width w3 of the vertical roller boss is 10-20mm, the height d of the lower horizontal roller boss is 63-89mm, and the slope θ of the lower horizontal roller boss is 1.0-3.5°.

[0029] In step S7, the cooling method is air cooling.

[0030] In step S8, a gantry straightening machine is used for straightening.

[0031] The present invention also provides a C-shaped steel for bridge bearings, which is prepared by the production method of the C-shaped steel for bridge bearings, has a C-shaped cross section, and has a boss on the outer side of the leg.

[0032] The cross-sectional dimensions of the C-shaped steel used for the bridge bearing are as follows: web width w is 631.7mm to 636.6mm, web thickness d is 48.0mm to 50.5mm, leg height b is 66.9mm to 69.9mm, and leg thickness t1 is 72.6mm to 75.4mm.

[0033] The thickness t2 of the boss is 11.2mm to 15.3mm, and the height h is 13.2mm to 20.3mm.

[0034] The yield strength of the C-shaped steel used for the bridge bearing is 363MPa~397MPa, the tensile strength is 532MPa~578MPa, the elongation after fracture is not less than 19.0%, and its impact energy at 20℃ is not less than 39J.

[0035] The chemical composition of the C-shaped steel used for the bridge bearings, by mass percentage, is as follows: C: 0.16~0.20, Si: 0.20~0.35, Mn: 1.31~1.45, P: ≤0.030, S: ≤0.020, V: 0.025~0.035, with the remainder being Fe and unavoidable impurities.

[0036] The production method of C-shaped steel for bridge bearings of the present invention effectively overcomes the inherent shortcomings of the die casting billet processing technology, and successfully produces high-performance, high-precision, and low-cost hot-rolled C-shaped steel for bridge bearings, which meets the production requirements of C-shaped steel for bridge bearings and can improve processing efficiency. Attached Figure Description

[0037] This manual includes the following figures, which illustrate the following:

[0038] Figure 1 This is a flowchart of the production method of C-shaped steel for bridge bearings according to the present invention;

[0039] Figure 2 This is a cross-sectional schematic diagram of the production method of C-shaped steel for bridge bearings according to the present invention;

[0040] Figure 3 This is a schematic diagram of the K1 hole type;

[0041] Figure 4 This is a schematic diagram of the K2 hole type;

[0042] Figure 5 This is a schematic diagram of the K3 hole type;

[0043] Figure 6 This is a schematic diagram of a universal UF aperture.

[0044] The markings in the diagram are: 1. Waist; 2. Legs; 3. Surface. Detailed Implementation

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention, and to facilitate its implementation.

[0046] Firstly, such as Figure 1 As shown in the figure, this invention provides a method for producing C-shaped steel for bridge bearings, comprising the following steps:

[0047] S1. Provide irregularly shaped cast billets that conform to the predetermined chemical composition;

[0048] S2. Heating the irregularly shaped billet to austenitize its microstructure;

[0049] S3. Dephosphorize the heated billet;

[0050] S4. The dephosphorized billet is rolled in a two-roll rolling mill for multiple passes. The multiple passes use a pass system with at least three passes. The pass system is designed to be asymmetrical from top to bottom and symmetrical from left to right.

[0051] S5. Trim the ends of the rolled piece after the billet rolling process.

[0052] S6. Universal rolling is performed on the rolled piece after the end is cut: a universal rolling mill is used for rolling. The universal rolling mill includes a UF pass. The lower horizontal roll of the UF pass is provided with a boss, and the vertical roll of the UF pass is provided with a boss, so that the boss of the rolled piece after rolling is located on both sides of its leg.

[0053] S7. Cool the rolled piece after universal rolling;

[0054] S8. Straighten the cooled rolled piece to obtain the finished product.

[0055] Specifically, this invention provides a hole structure and production method for C-shaped steel used in bridge bearings. It employs a reasonable hole structure, chemical composition, heating regime, and rolling process, resulting in a product with a yield strength of not less than 335 MPa, tensile strength of not less than 470 MPa, elongation of not less than 19.0%, and an impact energy value of not less than 34 J at 20°C. The product has a width of 500-750 mm, a web thickness of 40-60 mm, a leg length of 63-88 mm, and a leg thickness of 60-95 mm. The boss is located on the outer side of the leg, with a thickness of 10-20 mm and a height of 10-30 mm. This allows the boss to be quickly removed during machining using a vertical milling cutter, eliminating the need for top machining, reducing processing costs, and improving processing efficiency.

[0056] The production process of hot-rolled C-shaped steel for bridge bearings according to the present invention includes, in sequence: converter smelting, argon blowing refining, continuous casting of special-shaped billets, billet heating, descaling, billet rolling, end cutting, universal rolling, post-rolling air cooling, and straightening.

[0057] Furthermore, step S1 includes a converter smelting process, an argon blowing refining process, and a shaped billet continuous casting process.

[0058] In the converter smelting process, the amount of molten iron charged is 60±5 tons, the smelting time is 30±5 minutes, the endpoint is controlled by lance operation with a lance time of more than 20 seconds, and the tapping time is controlled to be more than 2 minutes.

[0059] In the argon blowing refining process, molten steel is treated with argon to homogenize the composition and temperature of the steel, and to remove gases and non-metallic inclusions from the steel, thereby purifying the molten steel.

[0060] The continuous casting process for irregularly shaped billets employs a fully protected casting technique. Specifically: quartz protective sleeves are used for ladle pouring; the open pouring time during each heat does not exceed 30 seconds; the continuous pouring cycle is 20±5 minutes; and argon gas is used for micro-positive pressure protection in the tundish. Zirconium sizing nozzles or quick-change sizing nozzles are used in the tundish; the crystallizer casting speed is automatically controlled, and external aluminum-carbon submersible nozzles or semi-submersible aluminum-carbon nozzles are used, ultimately casting near-net-shape irregularly shaped billets.

[0061] Furthermore, in step S1 above, the chemical composition of the irregularly shaped billet by mass percentage is as follows: C: 0.16~0.20, Si: 0.20~0.35, Mn: 1.31~1.45, P: ≤0.030, S: ≤0.020, V: 0.025~0.035, with the remainder being Fe and unavoidable impurities.

[0062] Furthermore, in step S2 above, the irregularly shaped billet is placed in a heating furnace for heating. The heating temperature is 1200℃~1280℃ and the time in the furnace is 120min~280min to ensure that the internal structure of the billet is fully and uniformly austenitized.

[0063] Furthermore, in step S3 above, the iron oxide scale formed on the surface of the billet during the heating process is removed by rinsing the surface of the billet with high-pressure water, and the dephosphorization water pressure is ≥16Mpa.

[0064] Furthermore, in step S4 above, a reciprocating two-roll rolling mill is used to roll and deform the billet through multiple passes during the billet rolling process. This gradually reduces the width and thickness of the billet, making its shape gradually closer to that of the finished product. At the same time, it improves the internal density of the structure, laying a good foundation for subsequent forming rolling.

[0065] In step S4 above, the roll pass system includes roll passes K1, K2, and K3 arranged sequentially. The roughing rolling roll passes K1, K2, and K3 are obtained through precise calculations and rolling simulations, and optimized based on actual production experience. Both the upper and lower roll passes adopt an asymmetrical design, with parallel upper and lower groove bottoms and parallel upper and lower waist sections.

[0066] like Figure 3 As shown, the structural parameters of the K1 hole type are as follows: the upper waist width a1 is equal to the lower waist width a2, which is 345-545mm; the upper groove bottom width b1 is equal to the lower groove bottom width b2, which is 78-102mm; the upper groove opening width c1 is equal to the lower groove opening width c2, which is 128-152mm; the upper groove depth d1 is 94-106mm, and the lower groove depth d2 is 114-136mm; the upper fillet R1 is equal to the lower fillet R2, which is 50-60mm.

[0067] like Figure 3 As shown, the upper waist width a1 and lower waist width a2 of the K1 hole profile refer to the total width a1 of the "waist" above the center line of the hole profile and the total width a2 of the "waist" below the center line in the vertical direction. In a specific design of this invention, a1 and a2 of the K1 hole profile are equal.

[0068] The upper groove bottom width b1 and lower groove bottom width b2 of the K1 hole type refer to the width b1 of the bottom of the groove located above the center line and the width b2 of the bottom of the groove located below the center line in the K1 hole type outline. In a specific design of the present invention, b1 and b2 of the K1 hole type are equal.

[0069] The upper groove width c1 and lower groove width c2 of the K1 hole type refer to the width c1 of the opening of the groove located above the center line and the width c2 of the opening of the groove located below the center line in the K1 hole type outline. In a specific design of the present invention, c1 and c2 of the K1 hole type are equal.

[0070] The upper groove depth d1 and lower groove depth d2 of the K1 hole type refer to the vertical distance d1 from the inner plane of the "waist" above the center line to the bottom of the groove on that side, and the vertical distance d2 from the inner plane of the "waist" below the center line to the bottom of the groove on that side.

[0071] The upper fillet R1 and lower fillet R2 of the K1 hole type refer to the transition fillet radii R1 on both sides of the bottom of the groove above the center line and the transition fillet radii R2 on both sides of the bottom of the groove below the center line in the K1 hole type outline. R1 and R2 are equal in the K1 hole type.

[0072] like Figure 4As shown, the structural parameters of the K2 hole type are as follows: upper waist width a1 is 320-520mm, lower waist width a2 is 360-560mm; upper groove bottom width b1 is 110-130mm, lower groove bottom width b2 is 100-120mm; upper groove opening width c1 is 160-180mm, lower groove opening width c2 is 140-160mm; upper groove depth d1 is 25-45mm, lower groove depth d2 is 75-95mm; upper fillet R1 is 60-80mm, lower fillet R2 is 30-40mm.

[0073] like Figure 4 As shown, the upper waist width a1 and lower waist width a2 of the K2 hole shape refer to the total width a1 of the "waist" above the center line of the hole shape and the total width a2 of the "waist" below the center line in the vertical direction of the K2 hole shape.

[0074] The bottom widths of the upper and lower grooves of the K2 hole type are b1 and b2 respectively: b1 refers to the bottom width of the groove located above the center line and b2 refers to the bottom width of the groove located below the center line in the K2 hole type outline.

[0075] The upper groove width c1 and lower groove width c2 of the K2 hole type refer to the width c1 of the opening of the groove located above the center line and the width c2 of the opening of the groove located below the center line in the K2 hole type outline.

[0076] The upper groove depth d1 and lower groove depth d2 of the K2 hole type refer to the vertical distance d1 from the inner plane of the "waist" above the center line to the bottom of the groove on that side, and the vertical distance d2 from the inner plane of the "waist" below the center line to the bottom of the groove on that side.

[0077] The upper fillet R1 and lower fillet R2 of the K2 hole type refer to the transition fillet radius R1 on both sides of the bottom of the groove above the center line and the transition fillet radius R2 on both sides of the bottom of the groove below the center line in the K2 hole type outline.

[0078] like Figure 5 As shown, the structural parameters of the K3 hole type are as follows: upper waist width a1 is 330-530mm, lower waist width a2 is 380-580mm; upper groove bottom width b1 is 131-141mm, lower groove bottom width b2 is 125-135mm; upper groove opening width c1 is 192-202mm, lower groove opening width c2 is 159-179mm; upper groove depth d1 is 65-85mm, lower groove depth d2 is 60-80mm; upper fillet R1 is 80-100mm, lower fillet R2 is 20-30mm.

[0079] like Figure 5As shown, the upper waist width a1 and lower waist width a2 of the K3 hole shape refer to the total width a1 of the "waist" above the center line of the hole shape and the total width a2 of the "waist" below the center line in the vertical direction of the K3 hole shape outline.

[0080] The bottom widths of the upper and lower grooves of the K3 hole type are b1 and b2 respectively: b1 refers to the bottom width of the groove located above the center line and b2 refers to the bottom width of the groove located below the center line in the K3 hole type outline.

[0081] The upper groove width c1 and lower groove width c2 of the K3 hole type refer to the width c1 of the opening of the groove located above the center line and the width c2 of the opening of the groove located below the center line in the K3 hole type outline.

[0082] The upper groove depth d1 and lower groove depth d2 of the K3 hole type refer to the vertical distance d1 from the inner plane of the "waist" above the center line to the bottom of the groove on that side, and the vertical distance d2 from the inner plane of the "waist" below the center line to the bottom of the groove on that side.

[0083] The upper fillet R1 and lower fillet R2 of the K3 hole type refer to the transition fillet radius R1 on both sides of the bottom of the groove above the center line and the transition fillet radius R2 on both sides of the bottom of the groove below the center line in the K3 hole type outline.

[0084] Furthermore, in step S5 above, cutting the end refers to the irregular protrusion at the end of the rolled piece after the billet has been rolled. In order to ensure the smooth progress of subsequent universal rolling, a hot saw is used to cut off the irregular part at the end of the rolled piece after the billet rolling.

[0085] Furthermore, in step S6 above, a reciprocating UR-E-UF universal rolling mill is used for rolling. The workpiece bite speed is 1-2 m / s, the rolling speed is 3-5 m / s, and the tail-striking speed is 1-2 m / s. With appropriate rolling passes and reduction, a workpiece with the required cross-sectional dimensions and strip shape is finally obtained. The universal pass is obtained through precise calculation and rolling simulation, and optimized based on actual production experience.

[0086] Due to the limitations of the universal rolling method, the finished product has bosses. To reduce the time required for subsequent machining, this invention optimizes the universal UF die by transferring the bosses 3 to both sides of the finished product's legs. The thickness of the bosses 3 is 20-35mm. Figure 2 As shown.

[0087] In step S6 above, the structural parameters of the UF die are as follows: the width w1 of the upper horizontal roller is 560-810mm, the width w2 of the lower horizontal roller boss is 356-606mm, the width w3 of the vertical roller boss is 10-20mm, the height d of the lower horizontal roller boss is 63-89mm, and the slope θ of the lower horizontal roller boss is 1.0-3.5°.

[0088] like Figure 6 As shown, the upper horizontal roller width w1 of the UF aperture refers to the width of the working roller surface of the upper horizontal roller that constitutes the UF aperture.

[0089] The width w2 of the lower horizontal roller boss in the UF die type refers to the top width of the boss structure on the lower horizontal roller that constitutes the UF die type, designed to achieve a specific product shape.

[0090] The width w3 of the vertical roller boss in the UF-type die refers to the width of the boss structure designed on the vertical roller that constitutes the UF-type die, corresponding to the position of the boss on the lower horizontal roller.

[0091] The height d of the lower horizontal roller boss in UF type refers to the vertical height from the root of the lower horizontal roller boss to its top surface.

[0092] The slope θ of the lower horizontal roller boss in UF type refers to the angle of inclination of the side of the lower horizontal roller boss relative to the vertical direction.

[0093] Furthermore, in step S7 above, the cooling method is air cooling. The rolled piece is laid flat on a walking beam chain cooling bed, allowing it to cool to a suitable temperature in the air to obtain suitable microstructure and properties.

[0094] Furthermore, in step S8 above, a gantry straightener is used for straightening. After the rolled workpiece is cooled to a suitable temperature, it is straightened by the gantry straightener to obtain a finished product with the required dimensions and shape.

[0095] Secondly, such as Figure 2 As shown, this embodiment of the invention also provides a C-shaped steel for bridge bearings, which is prepared by the above-described method for producing C-shaped steel for bridge bearings.

[0096] like Figure 2 As shown, the cross-section of the C-shaped steel used for the bridge bearing is C-shaped, including a waist 1 and two legs 2. The two legs 2 are connected to the two ends of the waist 1 in the width direction, respectively. The two legs 2 are perpendicular to the waist 1, extend towards the same side of the waist 1, and are parallel to each other. There is a boss 3 on the outside of the legs 2.

[0097] Furthermore, the cross-sectional dimensions of the C-shaped steel used for bridge bearings are as follows: web width w (width of the web section) is 631.7mm to 636.6mm, web thickness d (thickness of the web section) is 48.0mm to 50.5mm, leg height b is 66.9mm to 69.9mm, and leg thickness t1 is 72.6mm to 75.4mm. The width direction of the web section is perpendicular to the thickness direction of the web section, the height direction of the leg section is parallel to the thickness direction of the web section, and the thickness direction of the leg section is parallel to the width direction of the web section.

[0098] Furthermore, the thickness t2 of the boss is 11.2mm to 15.3mm, the height h of the boss is 13.2mm to 20.3mm, the height direction of the boss is parallel to the height direction of the leg, and the thickness direction of the boss is parallel to the width direction of the waist.

[0099] The yield strength of C-shaped steel used for bridge bearings is 363MPa~397MPa, the tensile strength is 532MPa~578MPa, the elongation after fracture is not less than 19.0%, and its impact energy at 20℃ is not less than 39J.

[0100] The chemical composition of C-shaped steel for bridge bearings, by mass percentage, is as follows: C: 0.16~0.20, Si: 0.20~0.35, Mn: 1.31~1.45, P: ≤0.030, S: ≤0.020, V: 0.025~0.035, with the remainder being Fe and unavoidable impurities.

[0101] In this invention, based on actual production conditions, the alloy composition ratio is reasonably adjusted to meet the control requirements of alloying elements in the actual production process. Combined with the actual on-site production process, a reasonable die shape is designed, realizing the reciprocating billet rolling + reciprocating universal rolling process. The hot-rolled C-shaped steel products produced have a strength greater than 335MPa, an elongation of not less than 19%, an impact energy value of not less than 34J at 20℃, and the product dimensions meet the requirements for processing the corresponding specifications of bridge bearing upper bearing plates.

[0102] The specific embodiments of the present invention will be further described in detail below through the description of the examples.

[0103] Example 1

[0104] This embodiment describes the preparation of hot-rolled C-shaped steel for bridge bearings. The chemical composition of the shaped billet used, by mass percentage, is: C: 0.18%, Si: 0.25%, Mn: 1.40%, P: 0.015%, S: 0.015%, V: 0.030%, with the remainder being Fe and unavoidable impurities. The billet is heated to 1271°C in a furnace for 185 minutes to ensure sufficient austenitization. After descaling with high-pressure water, the heated billet is sequentially rolled through K1, K2, and K3 passes. After the ends are removed, it is rolled into shape using the UF pass of a universal rolling mill, followed by air cooling and straightening. The mechanical properties of the resulting C-shaped steel are: yield strength R... eH The tensile strength is 363 MPa, and the tensile strength R is... m The strength of the sample is 532 MPa, the elongation after fracture (A) is 28.5%, and the impact energy (KV2) at 20℃ is 52.0 J (the values ​​for the three samples are 51 J, 61 J, and 44 J, respectively). Its cross-sectional dimensions are: waist width (w) 632.2 mm, waist thickness (d) 50.5 mm, leg height (b) 66.9 mm, leg thickness (t1) 72.6 mm, boss thickness (t2) 15.3 mm, and boss height (h) 20.3 mm.

[0105] Example 2

[0106] This embodiment describes the preparation of hot-rolled C-shaped steel for bridge bearings. The chemical composition of the shaped billet used, by mass percentage, is: C: 0.17%, Si: 0.30%, Mn: 1.33%, P: 0.022%, S: 0.017%, V: 0.026%, with the remainder being Fe and unavoidable impurities. The billet was heated to 1266°C in a furnace for 216 minutes. Subsequent processes, including billet rolling, universal rolling, cooling, and straightening, were the same as in Example 1. The mechanical properties of the resulting C-shaped steel are: yield strength R... eH The tensile strength is 365 MPa, and the tensile strength R is... m The strength is 555 MPa, the elongation after fracture (A) is 27.0%, and the impact energy (KV2) at 20℃ is 51.7 J (the values ​​for the three samples are 41 J, 53 J, and 61 J, respectively). Its cross-sectional dimensions are: waist width (w) 631.8 mm, waist thickness (d) 50.1 mm, leg height (b) 69.9 mm, leg thickness (t1) 73.1 mm, boss thickness (t2) 13.2 mm, and boss height (h) 16.5 mm.

[0107] Example 3

[0108] This embodiment describes the preparation of hot-rolled C-shaped steel for bridge bearings. The chemical composition of the shaped billet used, by mass percentage, is: C: 0.17%, Si: 0.30%, Mn: 1.33%, P: 0.022%, S: 0.017%, V: 0.029%, with the remainder being Fe and unavoidable impurities. The billet was heated to 1252°C in a furnace for 165 minutes. Subsequent processes, including billet rolling, universal rolling, cooling, and straightening, were the same as in Example 1. The mechanical properties of the resulting C-shaped steel are: yield strength R... eH The tensile strength is 378 MPa, and the tensile strength R is... m The strength of the metal is 578 MPa, the elongation after fracture (A) is 19.0%, and the impact energy (KV2) at 20℃ is 52.0 J (the values ​​for the three samples are 39 J, 63 J, and 54 J, respectively). Its cross-sectional dimensions are: waist width (w) 635.5 mm, waist thickness (d) 48.0 mm, leg height (b) 68.5 mm, leg thickness (t1) 74.5 mm, boss thickness (t2) 13.8 mm, and boss height (h) 16.5 mm.

[0109] Example 4

[0110] This embodiment describes the preparation of hot-rolled C-shaped steel for bridge bearings. The chemical composition of the shaped billet used, by mass percentage, is: C: 0.18%, Si: 0.27%, Mn: 1.39%, P: 0.017%, S: 0.012%, V: 0.028%, with the remainder being Fe and unavoidable impurities. The billet was heated to 1245°C in a furnace for 155 minutes. Subsequent processes, including billet rolling, universal rolling, cooling, and straightening, were the same as in Example 1. The mechanical properties of the resulting C-shaped steel are: yield strength R... eH The tensile strength is 374 MPa, and the tensile strength R is... m The strength of the sample is 552 MPa, the elongation after fracture (A) is 27.0%, and the impact energy (KV2) at 20℃ is 55.6 J (the values ​​for the three samples are 55 J, 63 J, and 49 J, respectively). Its cross-sectional dimensions are: waist width (w) 631.7 mm, waist thickness (d) 49.8 mm, leg height (b) 67.5 mm, leg thickness (t1) 73.5 mm, boss thickness (t2) 12.6 mm, and boss height (h) 15.6 mm.

[0111] Example 5

[0112] This embodiment describes the preparation of hot-rolled C-shaped steel for bridge bearings. The chemical composition of the shaped billet used, by mass percentage, is: C: 0.18%, Si: 0.25%, Mn: 1.37%, P: 0.025%, S: 0.013%, V: 0.027%, with the remainder being Fe and unavoidable impurities. The billet was heated to 1265°C in a furnace for 206 minutes. Subsequent processes, including billet rolling, universal rolling, cooling, and straightening, were the same as in Example 1. The mechanical properties of the resulting C-shaped steel are: yield strength R... eH The tensile strength is 397 MPa, and the tensile strength R is... m The strength of the sample is 563 MPa, the elongation after fracture (A) is 25.0%, and the impact energy (KV2) at 20℃ is 51.7 J (the values ​​for the three samples are 44 J, 54 J, and 57 J, respectively). Its cross-sectional dimensions are: waist width (w) 636.6 mm, waist thickness (d) 48.4 mm, leg height (b) 68.3 mm, leg thickness (t1) 75.4 mm, boss thickness (t2) 11.2 mm, and boss height (h) 13.2 mm.

[0113] As shown in the embodiments in Tables 1 to 4, the hot-rolled C-shaped steel products produced by the method described in this invention have a yield strength of 363~397MPa, a tensile strength of 532~578MPa, an elongation of 19.0%~28.5%, an impact energy of 39J~63J at 20℃, a web width of 631.7~636.6mm, a web thickness of 48.0~50.5mm, a leg height of 66.9~69.9mm, a leg thickness of 72.6~75.4mm, a boss thickness of 11.2-15.3mm, and a boss height of 13.2-20.3mm, which meets the requirements for processing into bridge bearings of corresponding specifications.

[0114]

[0115]

[0116]

[0117]

[0118] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for producing C-shaped steel for bridge bearings, characterized in that, Includes the following steps: S1. Provide irregularly shaped cast billets that conform to the predetermined chemical composition; S2. Heat the irregularly shaped billet to austenitize its microstructure; S3. Dephosphorize the heated billet; S4. The dephosphorized billet is rolled in a two-roll rolling mill for multiple passes. The multiple passes are rolled in a pass system with at least three passes. The pass system is designed to be asymmetrical from top to bottom and symmetrical from left to right. S5. Trim the ends of the rolled piece after the billet rolling process. S6. Universal rolling is performed on the rolled piece after the end is cut: a universal rolling mill is used for rolling. The universal rolling mill includes a UF die. The lower horizontal roll of the UF die is provided with a boss, and the vertical roll of the UF die is provided with a boss, so that the boss of the rolled piece after rolling is located on both sides of its leg. S7. Cool the rolled piece after universal rolling; S8. Straighten the cooled rolled piece to obtain the finished product.

2. The production method according to claim 1, characterized in that, The chemical composition of the irregularly shaped billet, by mass percentage, is as follows: C: 0.16-0.20, Si: 0.20-0.35, Mn: 1.31-1.45, P: ≤0.030, S: ≤0.020, V: 0.025-0.035, with the remainder being Fe and unavoidable impurities.

3. The production method according to claim 1, characterized in that, In step S2, the heating temperature is 1200℃~1280℃, and the furnace time is 120min~280min.

4. The production method according to claim 1, characterized in that, In step S4, the hole pattern system includes hole patterns K1, K2 and K3 arranged sequentially.

5. The production method according to claim 4, characterized in that, The structural parameters of the K1 hole type are as follows: the upper waist width a1 and the lower waist width a2 are equal, which is 345-545mm; the upper groove bottom width b1 and the lower groove bottom width b2 are equal, which is 78-102mm; the upper groove opening width c1 and the lower groove opening width c2 are equal, which is 128-152mm; the upper groove depth d1 is 94-106mm, and the lower groove depth d2 is 114-136mm; the upper fillet R1 is equal to the lower fillet R2, which is 50-60mm.

6. The production method according to claim 4, characterized in that, The structural parameters of the K2 hole type are as follows: upper waist width a1 is 320-520mm, lower waist width a2 is 360-560mm; upper groove bottom width b1 is 110-130mm, lower groove bottom width b2 is 100-120mm; upper groove opening width c1 is 160-180mm, lower groove opening width c2 is 140-160mm; upper groove depth d1 is 25-45mm, lower groove depth d2 is 75-95mm; upper fillet R1 is 60-80mm, lower fillet R2 is 30-40mm.

7. The production method according to claim 4, characterized in that, The structural parameters of the K3 hole type are as follows: upper waist width a1 is 330-530mm, lower waist width a2 is 380-580mm; upper groove bottom width b1 is 131-141mm, lower groove bottom width b2 is 125-135mm; upper groove opening width c1 is 192-202mm, lower groove opening width c2 is 159-179mm; upper groove depth d1 is 65-85mm, lower groove depth d2 is 60-80mm; upper fillet radius R1 is 80-100mm, lower fillet radius R2 is 20-30mm.

8. The production method according to any one of claims 1 to 7, characterized in that, In step S5, a hot saw is used to remove the irregular portion at the end of the rolled piece after the initial rolling process.

9. The production method according to any one of claims 1 to 7, characterized in that, In step S6, the structural parameters of the UF die are as follows: the width w1 of the upper horizontal roller is 560-810mm, the width w2 of the lower horizontal roller boss is 356-606mm, the width w3 of the vertical roller boss is 10-20mm, the height d of the lower horizontal roller boss is 63-89mm, and the slope θ of the lower horizontal roller boss is 1.0-3.5°.

10. The production method according to any one of claims 1 to 7, characterized in that, In step S7, the cooling method is air cooling.

11. The production method according to any one of claims 1 to 7, characterized in that, In step S8, a gantry straightening machine is used for straightening.

12. A C-shaped steel for bridge bearings, characterized in that, It is manufactured by the production method of C-shaped steel for bridge bearings according to any one of claims 1 to 11, and has a C-shaped cross section and a boss on the outer side of the leg.

13. The C-shaped steel for bridge bearings according to claim 12, characterized in that, The cross-sectional dimensions of the C-shaped steel used for the bridge bearing are as follows: web width w is 631.7mm to 636.6mm, web thickness d is 48.0mm to 50.5mm, leg height b is 66.9mm to 69.9mm, and leg thickness t1 is 72.6mm to 75.4mm.

14. The C-shaped steel for bridge bearings according to claim 13, characterized in that, The thickness t2 of the boss is 11.2mm to 15.3mm, and the height h is 13.2mm to 20.3mm.

15. The C-shaped steel for bridge bearings according to claim 12, characterized in that, The yield strength of the C-shaped steel used for the bridge bearing is 363MPa~397MPa, the tensile strength is 532MPa~578MPa, the elongation after fracture is not less than 19.0%, and its impact energy at 20℃ is not less than 39J.

16. The C-shaped steel for bridge bearings according to any one of claims 12 to 15, characterized in that, The chemical composition of the C-shaped steel used for the bridge bearings, by mass percentage, is as follows: C: 0.16~0.20, Si: 0.20~0.35, Mn: 1.31~1.45, P: ≤0.030, S: ≤0.020, V: 0.025~0.035, with the remainder being Fe and unavoidable impurities.

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