CN116043113A - Pre-welded preheating-free bridge steel produced by TMCP (thermal mechanical control process) process and preparation method thereof - Google Patents

Pre-welded preheating-free bridge steel produced by TMCP (thermal mechanical control process) process and preparation method thereof Download PDF

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CN116043113A
CN116043113A CN202310036935.4A CN202310036935A CN116043113A CN 116043113 A CN116043113 A CN 116043113A CN 202310036935 A CN202310036935 A CN 202310036935A CN 116043113 A CN116043113 A CN 116043113A
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less
percent
rolling
temperature
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欧阳瑜
陈尹泽
程官江
黄重
韦弦
宋立伟
孙斌
李娜
徐博
赵良生
张青龙
汲霖
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Anyang Iron and Steel Co Ltd
Anyang Iron and Steel Group Co Ltd
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Anyang Iron and Steel Co Ltd
Anyang Iron and Steel Group Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
    • B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/58—Roll-force control; Roll-gap control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
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    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D11/00—Process control or regulation for heat treatments
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    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0231—Warm rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/02—Iron or ferrous alloys
    • B23K2103/04—Steel or steel alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The application discloses a pre-welding preheating-free bridge steel produced by a TMCP process and a preparation method thereof, and relates to the field, wherein the pre-welding preheating-free bridge steel comprises the following chemical components in percentage by weight: c:0.05-0.09%, si:0.12-0.60%, mn:1.50-1.85%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, cr:0.25-0.50%, nb:0.015% -0.060%, al:0.010% -0.060%, ti:0.008 to 0.035 percent, less than or equal to 0.005 percent of B, less than or equal to 0.0070 percent of N, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, less than or equal to 0.08 percent of Mo, less than or equal to 0.15 percent of Ni, less than or equal to 0.15 percent of Cu, and the balance of Fe and unavoidable impurities; the technical key point is that precious metals Mo, ni and Cu are not added in the components of the steel, the effect of C, mn, cr, B elements is fully exerted, and the 620 MPa-grade bridge steel is obtained by adopting controlled rolling and three-stage controlled cooling processes, so that the manufacturing process is simple and the preparation cost is low.

Description

Pre-welded preheating-free bridge steel produced by TMCP (thermal mechanical control process) process and preparation method thereof
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to pre-welding preheating-free bridge steel produced by a TMCP (thermal mechanical control process) process and a preparation method thereof.
Background
Along with the development of national economic construction, large bridges are leapfully developed towards the direction of large span and heavy load, and the application proportion of steel structure bridges is larger and larger; along with the lifting of bridge span, new requirements are also put forward on the aspects of high strength, high toughness, welding performance and the like of the used steel plates; welding is an indispensable step in the manufacturing and mounting processes of the steel structure bridge, and is one of key factors related to the service life and safety of the bridge, so that high-performance bridge steel with excellent welding performance is widely demanded in industry under the condition of low preheating or no preheating.
The steel plate with the yield strength of 620MPa is usually over 720MPa, and in order to prevent cold crack tendency generated during welding of the bridge steel with the yield strength of 620MPa, preheating is required to be carried out before welding at the temperature of over 50 ℃ corresponding to the welding process, so that the actual production process is time-consuming, and the production efficiency is directly reduced.
Before the invention is put forward, some similar technical products in the field of bridge steel manufacturing are related, but alloy elements are added more, welding needs preheating, the welding performance requirement of high-strength steel cannot be met, and the cost is high.
Such as: chinese patent 'a low-cost high-performance bridge steel and a production method thereof', patent application number CN201810020004.4, wherein the bridge steel comprises the following chemical components in percentage by mass: c:0.04-0.09%, mn:1.40-1.60%, S is less than or equal to 0.0050%, P is less than or equal to 0.015%, si:0.10-0.30%, al s:0.020-0.050%, nb:0.035-0.055%, ti:0.006-0.020%, mo:0-0.20%, and the balance being Fe and unavoidable impurities; the production method comprises the working procedures of molten iron pretreatment, converter smelting, LF refining, RH refining, continuous casting, heating, rough rolling, finish rolling and cooling. The high-performance bridge steel does not add expensive alloy elements such as Cr, ni, cu and the like, has the competitive advantage of low cost, and simultaneously has excellent notch impact toughness, low-temperature impact toughness and good weldability. However, the steel has low strength grade, belongs to 420MPa grade, and if the strength is required to be improved, the components and the process can be greatly changed;
the Chinese patent 'a low-yield-ratio high-performance bridge steel and a manufacturing method thereof', the patent application No. 20151022080. X, provides a bridge steel, which comprises the following chemical components in percentage by mass: 0.04 to 0.08 percent of C, 0.30 to 0.50 percent of S i, 1.10 to 1.80 percent of Mn, less than or equal to 0.009 percent of P, less than or equal to 0.003 percent of S, less than or equal to 0.05 percent of Al, 0.20 to 0.50 percent of N i, 0.30 to 0.60 percent of Cr, 0.30 to 0.60 percent of Cu, 0.01 to 0.03 percent of T i, 0.02 to 0.05 percent of Nb and the balance of Fe, and the manufacturing method comprises the steps of rolling a billet in two stages, ultra-fast cooling after rolling, and air cooling to room temperature; the metallographic microstructure of the alloy consists of high-temperature and low-temperature bainite and refined martensite-austenite island components. The steel realizes high and low temperature toughness and low yield ratio while guaranteeing strength, and fills up the blank of research and development of the domestic low yield ratio Mo-free bridge steel. However, the steel is added with more alloying elements such as Cu, cr, ni and the like in the design, so that the cost is high, the strength is high, the preheating temperature of the 50mm steel plate is above 50 ℃, and in the actual welding process, the preheating temperature is higher according to the change of the ambient temperature and the selection of welding materials, thereby bringing great difficulty to production and construction.
The Chinese patent No. CN201810020004.4 provides a rare earth treated high strength steel plate with low preheating temperature and 690MPa grade and a preparation method thereof, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.09-0.15%, S i:0.30 to 0.45 percent, mn:1.58 to 1.75 percent, P is less than or equal to 0.02 percent, S is less than or equal to 0.010 percent, nb:0.04 to 0.08 percent, V:0.05 to 0.08 percent, T i:0.010 to 0.020%, cr:0.20 to 0.40 percent, la is less than or equal to 0.030 percent, al t: 0.020-0.050%, N is less than or equal to 0.005%, and O is less than or equal to 0.004%. The 690 MPa-grade high-strength steel plate is added with rare earth but not N i and Mo, has low preheating temperature, reduces cost, improves comprehensive mechanical properties through rare earth treatment, prolongs service life, and has good economic benefit. However, the minimum theoretical preheating temperature of the steel plate with the thickness of 50mm is 50 ℃, and the preheating temperature in the actual welding process is higher in consideration of other environmental factors; secondly, the steel belongs to medium carbon steel, has relatively high carbon content, contains higher noble alloy element V, and has higher cost; finally, the steel is treated by adopting a quenching and tempering heat treatment process to obtain a tempered sorbite structure steel plate, the cost is higher, and the current domestic bridge steel market generally does not accept the steel grade in the delivery state.
According to the research, the steel plate for the high-strength bridge, which can meet the requirements of high strength and high toughness of the steel plate and has excellent welding performance, is developed, and becomes a problem to be solved in the industry urgently.
Disclosure of Invention
The technical problems to be solved are as follows:
aiming at the defects of the prior art, the invention provides pre-welding preheating-free bridge steel produced by a TMCP process and a preparation method thereof, and solves the problems in the background art.
The technical scheme is as follows:
in order to achieve the above purpose, the invention is realized by the following technical scheme:
the pre-welding preheating-free bridge steel produced by the TMCP process comprises the following chemical components in percentage by weight:
c:0.05-0.09%, S i:0.12-0.60%, mn:1.50-1.85%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, cr:0.25-0.50%, nb:0.015% -0.060%, al:0.010% -0.060%, ti:0.008 to 0.035 percent, less than or equal to 0.005 percent of B, less than or equal to 0.0070 percent of N, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, less than or equal to 0.08 percent of Mo, less than or equal to 0.15 percent of Ni, less than or equal to 0.15 percent of Cu, and the balance of Fe and unavoidable impurities.
Preferably, the preparation method of the preheating-free bridge steel comprises the following specific steps:
comprises the pretreatment of molten iron;
a top-bottom combined blown converter;
LF refining;
vacuum refining by VD;
continuously casting a plate blank;
rolling by a steckel mill; and
three-stage controlled cooling.
Preferably, in the molten iron pretreatment,
the S content in the molten iron is more than or equal to 0.040%, and the S content is controlled to be less than or equal to 0.010% by adopting a molten iron pretreatment procedure for desulfurization.
Preferably, in the top-bottom combined blown converter,
oxygen blowing is carried out for 14-16min, steel tapping ensures that the molten steel P is less than or equal to 0.015 percent, S is less than or equal to 0.020 percent and O is less than or equal to 0.06 percent.
Preferably, in the LF refining,
in the LF refining process, the whole process is used for controlling aluminum, and meanwhile, argon is matched with the aluminum in the later stage of the LF furnace to be weakly stirred for 5min, so that the temperature gradient in molten steel is eliminated, the vacuum degree in the VD degassing process is less than or equal to 0.67mbar, and the smelting holding time of the highest vacuum degree is not less than 10min.
Preferably, in the LF refining and VD vacuum refining processes,
the molten steel temperature and composition meet continuous casting and target composition requirements, wherein the gas: n is less than or equal to 0.0060 percent, O is less than or equal to 0.0030 percent, and H is less than or equal to 0.0002 percent.
Preferably, in the continuous slab casting,
the whole process adopts protection casting, the fluctuation of the pulling speed is +/-0.05 m/min, the fluctuation of the molten steel surface of the cleaner is +/-3 mm, and the superheat degree of the molten steel is controlled at 10-25 ℃.
Preferably, in the steckel mill rolling,
the method comprises the following steps:
s1, reheating a plate blank, wherein the specific temperature is as follows: controlling the heating rate at 6-8 ℃/s at 1200-1250 ℃ and preserving heat at 1150-1250 ℃ to be not lower than 30min;
s2, rolling temperature interval of a recrystallization zone: 980-1150 ℃, the rolling pass reduction rate of the recrystallization zone is more than or equal to 15%, and the total rolling reduction rate of the recrystallization zone is more than or equal to 35%;
s3, rolling a non-recrystallization zone in a rolling temperature interval: the initial rolling temperature of the finish rolling is 800-960 ℃, the rolling total rolling reduction of the non-recrystallization zone is more than or equal to 60%, and the final rolling temperature range is as follows: 740-850 ℃;
s4, adopting three-stage control cooling after rolling;
wherein, in the first stage, air cooling is adopted, the air cooling starting temperature is 740-850 ℃, and the air cooling ending temperature is 700-780 ℃;
the second stage begins to cool at 700-780 deg.C, the redback temperature is 350-430 deg.C, the ratio of water to water is 1:1.25-1.30, the cooling rate is 15-30 deg.C/s;
and in the third stage, air cooling is carried out to room temperature.
The yield strength of the steel plate produced by the preparation method is more than or equal to 620MPa, the tensile strength is more than or equal to 720MPa, the elongation A is more than or equal to 15%, the longitudinal impact energy at-20 ℃ is more than or equal to 120J, and the metallographic structure is low-carbon bainite.
The beneficial effects are that:
firstly, precious metals Mo, N i and Cu are not added in the components of the steel, the effect of C, mn, cr, B elements is fully exerted, and the 620 MPa-grade bridge steel is obtained by adopting controlled rolling and three-stage controlled cooling processes, so that the manufacturing process is simple and the preparation cost is low.
Secondly, the yield strength of the steel plate produced by the manufacturing method is more than or equal to 620MPa, the tensile strength is more than or equal to 720MPa, the elongation A is more than or equal to 15 percent, and the longitudinal impact energy at-20 ℃ is more than or equal to 120J.
Thirdly, the 620MPa bridge steel manufactured by the method realizes preheating-free before welding.
Detailed Description
The pre-welding preheating-free bridge steel produced by the TMCP process and the preparation method thereof solve the problems in the prior art.
The technical scheme in the embodiment of the application aims to solve the problems, and the overall thought is as follows:
example 1:
the invention is further described by taking 620MPa grade bridge steel with the thickness of 20mm as an example by adopting a controlled rolling and three-stage controlled cooling process through taking C, mn, cr, B elements as full play by using the steckel mill production line without adding noble metals Mo, N i and Cu into the components.
The non-quenched and tempered steel comprises the following components in percentage by weight: c:0.07%, si:0.20%, mn:1.68%, P:0.008%, S:0.002%, nb:0.035%, cr:0.29%, al:0.034%, B:0.0016%, T i:0.015%, N:0.0048% and the balance Fe and unavoidable impurities.
The production process route of the embodiment comprises molten iron pretreatment, top-bottom combined blown converter, LF refining, VD degassing refining, wide slab continuous casting, steckel mill controlled rolling and three-stage controlled cooling;
wherein, molten iron pretreatment: the S content of molten iron is more than or equal to 0.040%, desulfurization is carried out by adopting a molten iron pretreatment procedure, and the S content is controlled to be less than or equal to 0.010%; oxygen blowing is performed by a top-bottom combined blowing converter for 14 min, steel tapping ensures that molten steel P is less than or equal to 0.015%, S is less than or equal to 0.020%, and O is less than or equal to 0.06%; in the LF refining process, the whole process is used for controlling aluminum, and meanwhile, argon is matched with the low-intensity stirring for 5min in the later stage of the LF furnace, so that the temperature uniformity of the VD furnace on molten steel is ensured, and the temperature gradient in the molten steel is eliminated; vacuum degree is less than or equal to 0.67mbar in the VD degassing process, and smelting holding time of the highest vacuum degree is not less than 10mi n; LF refining and VD vacuum refining treatment, wherein the temperature and the composition of molten steel meet the requirements of continuous casting and target compositions, and the gas is as follows: n is less than or equal to 0.0060%, O is less than or equal to 0.0030%, and H is less than or equal to 0.0002%; the continuous casting adopts the whole-process protection casting, the fluctuation of the pulling speed is +/-0.05 m/min, the fluctuation of the molten steel surface of the cleaner is +/-3 mm, and the superheat degree of the molten steel is controlled at 10 ℃.
The mill pass schedule for steckel mill is shown in table 1.
The method comprises the following steps: the reheating temperature of the slab is 1240 ℃, the rolling pass and the accumulated rolling reduction rate of the recrystallization zone and the non-recrystallization zone are shown in table 2 in the furnace time of 145mi n and the soaking time of 30mi n, the initial rolling temperature of the recrystallization zone is 1090 ℃, the final rolling temperature of the recrystallization zone is 1034 ℃, the rolling pass rolling reduction rate of the recrystallization zone is more than or equal to 15%, and the rolling total rolling reduction rate of the recrystallization zone is 50%; the initial rolling temperature of the non-recrystallization zone is 916 ℃, the final rolling temperature of the non-recrystallization zone is 796 ℃, and the rolling total rolling reduction of the non-recrystallization zone is 74%; three-stage control cooling is adopted after rolling, wherein air cooling is adopted in the first stage, the air cooling starting temperature is 796 ℃, and the air cooling ending temperature is 766 ℃; the second stage begins to cool at 766 ℃, the redback temperature is 350 ℃, the ratio of water to water is 1:1.25, and the cooling rate is 25 ℃/s; the final cooling temperature range is 380 ℃.
Table 1: steckel mill Rolling Process System of example 1
Figure BDA0004048867080000061
Table 2: steckel mill rolling pass schedule of example 1
Figure BDA0004048867080000062
The steel sheets produced according to the procedure of this example have the performance indexes shown in Table 3.
Table 3: performance index of steel sheet produced in example 1
Figure BDA0004048867080000063
As can be seen from Table 3, the 620MPa bridge steel which does not contain Mo, ni and Cu heavy metal elements produced by adopting the TMCP process can meet the requirements of product strength, toughness, plasticity and the like, and has a certain margin.
Wherein Mn:1.68%, B:0.0016%, cr:0.029%, T i:0.015%, al:0.028%, N:0.0045%, the quenching performance of the steel is strong by regulating the ratio of the quenching element C, mn, cr, B, the whole-process grain refining control is performed by controlling the rolling and three-stage control cooling process, the low-carbon bainite is obtained, the good impact toughness is obtained, and the impact energy at the low temperature of minus 20 ℃ can reach more than 120J, which is one of the core technologies of the invention.
Example 2:
the invention is further described by taking 620MPa grade bridge steel with 30mm thickness as an example by adopting a controlled rolling and three-stage controlled cooling process through taking C, mn, cr, B elements as full play by using the steckel mill production line without adding noble metals Mo, N i and Cu into the components.
The non-quenched and tempered steel comprises the following components in percentage by weight: c:0.06%, si:0.20%, mn:1.66%, P:0.010%, S:0.001%, nb:0.037%, cr:0.29%, al:0.035%, B:0.0017%, T i:0.017%, N:0.0042% and the balance Fe and unavoidable impurities.
The production process route of the embodiment comprises molten iron pretreatment, top-bottom combined blown converter, LF refining, VD degassing refining, wide slab continuous casting, steckel mill controlled rolling and three-stage controlled cooling. Wherein, molten iron pretreatment: the S content of molten iron is more than or equal to 0.040%, desulfurization is carried out by adopting a molten iron pretreatment procedure, and the S content is controlled to be less than or equal to 0.010%; oxygen blowing is performed by a top-bottom combined blowing converter for 14 min, steel tapping ensures that molten steel P is less than or equal to 0.015%, S is less than or equal to 0.020%, and O is less than or equal to 0.06%; in the LF refining process, the whole process is used for controlling aluminum, meanwhile, argon is matched with the aluminum in the later stage of the LF furnace for weak stirring for 5min, so that the temperature uniformity of the VD furnace on the molten steel is ensured, and the temperature gradient in the molten steel is eliminated. Vacuum degree is less than or equal to 0.67mbar in the VD degassing process, and smelting holding time of the highest vacuum degree is not less than 10mi n; LF refining and VD vacuum refining treatment, wherein the temperature and the composition of molten steel meet the requirements of continuous casting and target compositions, and the gas is as follows: n is less than or equal to 0.0060%, O is less than or equal to 0.0030%, and H is less than or equal to 0.0002%; the continuous casting adopts the whole-process protection casting, the fluctuation of the pulling speed is +/-0.05 m/min, the fluctuation of the molten steel surface of the cleaner is +/-3 mm, and the superheat degree of the molten steel is controlled at 10 ℃;
wherein, the rolling process schedule of the steckel mill is shown in Table 4.
The method comprises the following steps: the reheating temperature of the slab is 1240 ℃, the rolling pass and the accumulated rolling reduction rate of the recrystallization zone and the non-recrystallization zone are shown in table 5 in the furnace time of 145 mit and the soaking time of 30 mit, the initial rolling temperature of the recrystallization zone is 1100 ℃, the final rolling temperature of the recrystallization zone is 1046 ℃, the rolling pass rolling reduction rate of the recrystallization zone is more than or equal to 15% (at least one pass is reached), and the rolling total rolling reduction rate of the recrystallization zone is 37%; the initial rolling temperature of the non-recrystallization zone is 878 ℃, the final rolling temperature of the non-recrystallization zone is 795 ℃, and the rolling total rolling reduction of the non-recrystallization zone is 66.8%; three-stage control cooling is adopted after rolling, wherein air cooling is adopted in the first stage, the air cooling starting temperature is 795 ℃, and the air cooling ending temperature is 765 ℃; the second stage begins to cool at 765 ℃, the redback temperature is 370 ℃, the ratio of water to water is 1:1.25, and the cooling rate is 28 ℃/s; the final cooling temperature range is 380 ℃.
Table 4: the steckel mill rolling process regime of example 2
Figure BDA0004048867080000081
Table 5: steckel mill rolling pass schedule of example 2
Figure BDA0004048867080000082
The performance index of the steel sheet produced according to the procedure of this example is shown in Table 6.
Table 6: performance index of steel sheet produced in example 2
Figure BDA0004048867080000083
Figure BDA0004048867080000091
As can be seen from Table 6, the 620MPa bridge steel which does not contain Mo, N i and Cu heavy metal elements produced by adopting the TMCP process can meet the requirements of product strength, toughness, plasticity and the like.
Wherein Mn:1.66%, B:0.0017%, cr:0.029%, T i:0.017%, A l:0.035%, N:0.0042%, the ratio of the element C, mn, cr, B with the controlled hardenability is very strong, the whole-course grain refining control is carried out by controlling rolling and three-stage control cooling process, the low-carbon bainite is obtained, good impact toughness is obtained, the low temperature is minus 20 ℃, and the impact energy can reach more than 120J, which is one of the core technologies of the invention.
After the welding test is carried out on the steel plate with the thickness of 20mm prepared in the embodiment 2 of the invention, the obtained steel plate has excellent crack resistance, the surface and section crack rate is 0, and no preheating is needed. In combination, the steel provided by the invention has good comprehensive performance, can be used for highway bridges, railway bridges and highway and railway bridges with certain requirements on steel plate strength, low-temperature toughness, welding performance and the like, can effectively reduce the steel consumption of the bridges, reduce the dead weight of the bridges, reduce the maintenance cost and improve the use safety.
Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made without departing from the principles and spirit of the invention.
Finally, it should be noted that: it is apparent that the above examples are only illustrative of the present invention and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims (9)

1. The pre-welding preheating-free bridge steel produced by the TMCP process is characterized by comprising the following chemical components in percentage by weight:
c:0.05-0.09%, si:0.12-0.60%, mn:1.50-1.85%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, cr:0.25-0.50%, nb:0.015% -0.060%, al:0.010% -0.060%, ti:0.008 to 0.035 percent, less than or equal to 0.005 percent of B, less than or equal to 0.0070 percent of N, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, less than or equal to 0.08 percent of Mo, less than or equal to 0.15 percent of Ni, less than or equal to 0.15 percent of Cu, and the balance of Fe and unavoidable impurities.
2. The pre-weld preheating-free bridge steel produced by the TMCP process of claim 1, wherein: the preparation method of the preheating-free bridge steel comprises the following specific steps:
comprises the pretreatment of molten iron;
a top-bottom combined blown converter;
LF refining;
vacuum refining by VD;
continuously casting a plate blank;
rolling by a steckel mill; and
three-stage controlled cooling.
3. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the pretreatment of the molten iron,
the S content in the molten iron is more than or equal to 0.040%, and the S content is controlled to be less than or equal to 0.010% by adopting a molten iron pretreatment procedure for desulfurization.
4. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the top-bottom combined blown converter,
oxygen blowing is carried out for 14-16min, steel tapping ensures that the P content of molten steel is less than or equal to 0.015 percent, the S content is less than or equal to 0.020 percent, and the O content is less than or equal to 0.06 percent.
5. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the course of the said LF refining,
in the LF refining process, the whole process is used for controlling aluminum, and meanwhile, argon is matched with the low-intensity stirring for 5min at the later stage of the LF furnace, so that the temperature gradient in molten steel is eliminated, the vacuum degree in the VD degassing process is less than or equal to 0.67mbar, and the smelting holding time of the highest vacuum degree is not less than 10min.
6. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the LF refining and VD vacuum refining processes,
the molten steel temperature and composition meet continuous casting and target composition requirements, wherein the gas: n is less than or equal to 0.0060 percent, O is less than or equal to 0.0030 percent, and H is less than or equal to 0.0002 percent.
7. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the continuous casting of a slab in question,
the whole process adopts protection casting, the fluctuation of the pulling speed is +/-0.05 m/min, the fluctuation of the surface of the molten steel of the cleaner is +/-3 mm, and the superheat degree of the molten steel is controlled at 10-25 ℃.
8. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: in the rolling of the steckel mill,
the method comprises the following steps:
s1, reheating a plate blank, wherein the specific temperature is as follows: controlling the heating rate at 6-8deg.C/s at 1200-1250 deg.C, and maintaining the temperature at 1150-1250 deg.C for not less than 30min;
s2, rolling temperature interval of a recrystallization zone: 980-1150 ℃, the rolling pass reduction rate of the recrystallization zone is more than or equal to 15%, and the total rolling reduction rate of the recrystallization zone is more than or equal to 35%;
s3, rolling a non-recrystallization zone in a rolling temperature interval: the initial rolling temperature of the finish rolling is 800-960 ℃, the rolling total rolling reduction of the non-recrystallization zone is more than or equal to 60%, and the final rolling temperature range is as follows: 740-850 ℃;
s4, adopting three-stage control cooling after rolling;
wherein, in the first stage, air cooling is adopted, the air cooling starting temperature is 740-850 ℃, and the air cooling ending temperature is 700-780 ℃;
the second stage begins to cool at 700-780 deg.C, the redback temperature is 350-430 deg.C, the ratio of water to water is 1:1.25-1.30, the cooling rate is 15-30 deg.C/s;
and in the third stage, air cooling is carried out to room temperature.
9. The method for preparing the pre-welding preheating-free bridge steel produced by the TMCP process as claimed in claim 2, wherein the method comprises the following steps: the yield strength of the steel plate produced by the preparation method is more than or equal to 620MPa, the tensile strength is more than or equal to 720MPa, the elongation A is more than or equal to 15%, the longitudinal impact energy at-20 ℃ is more than or equal to 120J, and the metallographic structure is low-carbon bainite.
CN202310036935.4A 2023-01-10 2023-01-10 Pre-welded preheating-free bridge steel produced by TMCP (thermal mechanical control process) process and preparation method thereof Pending CN116043113A (en)

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CN117604389A (en) * 2023-12-09 2024-02-27 河北普阳钢铁有限公司 Production method of 420 MPa-level low-alloy high-strength steel easy to weld

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* Cited by examiner, † Cited by third party
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CN114480962A (en) * 2021-12-24 2022-05-13 安阳钢铁集团有限责任公司 Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof

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CN114480962A (en) * 2021-12-24 2022-05-13 安阳钢铁集团有限责任公司 Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117604389A (en) * 2023-12-09 2024-02-27 河北普阳钢铁有限公司 Production method of 420 MPa-level low-alloy high-strength steel easy to weld
CN117604389B (en) * 2023-12-09 2024-04-30 河北普阳钢铁有限公司 Production method of 420 MPa-level low-alloy high-strength steel easy to weld

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