CN116673323A - Manufacturing method of high-strength anti-seismic steel bar with high yield ratio - Google Patents
Manufacturing method of high-strength anti-seismic steel bar with high yield ratio Download PDFInfo
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- CN116673323A CN116673323A CN202310738331.4A CN202310738331A CN116673323A CN 116673323 A CN116673323 A CN 116673323A CN 202310738331 A CN202310738331 A CN 202310738331A CN 116673323 A CN116673323 A CN 116673323A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 131
- 239000010959 steel Substances 0.000 title claims abstract description 131
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 25
- 238000005096 rolling process Methods 0.000 claims abstract description 100
- 238000010438 heat treatment Methods 0.000 claims abstract description 90
- 238000001816 cooling Methods 0.000 claims abstract description 67
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000003723 Smelting Methods 0.000 claims abstract description 11
- 238000005266 casting Methods 0.000 claims abstract description 11
- 238000010008 shearing Methods 0.000 claims abstract description 11
- 229910052720 vanadium Inorganic materials 0.000 claims description 23
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- 229910001562 pearlite Inorganic materials 0.000 claims description 12
- 238000002791 soaking Methods 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 11
- 229910052698 phosphorus Inorganic materials 0.000 claims description 11
- 239000000126 substance Substances 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 9
- 238000004321 preservation Methods 0.000 claims description 8
- 229910000859 α-Fe Inorganic materials 0.000 claims description 7
- 239000000498 cooling water Substances 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 7
- 238000001556 precipitation Methods 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 7
- 230000003014 reinforcing effect Effects 0.000 description 6
- 230000035939 shock Effects 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 229910001566 austenite Inorganic materials 0.000 description 4
- 238000010276 construction Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
Classifications
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- 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
- B21B1/16—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 wire rods, bars, merchant bars, rounds wire or material of like small cross-section
- B21B1/18—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 wire rods, bars, merchant bars, rounds wire or material of like small cross-section in a continuous process
-
- 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
- B21B1/16—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 wire rods, bars, merchant bars, rounds wire or material of like small cross-section
- B21B1/163—Rolling or cold-forming of concrete reinforcement bars or wire ; Rolls therefor
-
- 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
-
- 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
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires 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
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/08—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires for concrete reinforcement
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
-
- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2275/00—Mill drive parameters
- B21B2275/02—Speed
- B21B2275/06—Product speed
-
- 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
- C21D2211/005—Ferrite
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- 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
- C21D2211/009—Pearlite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention belongs to the technical field of high-strength steel bars, and discloses a manufacturing method of a high-strength anti-seismic steel bar with high yield ratio, which comprises the following steps: 1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets; 2) Heating a steel billet: the billet enters a heating furnace to be heated in three sections, and the heating process involves the control of temperature, heating speed and heating time; 3) Rough rolling: controlling the temperature when entering a roughing mill set; 4) Finish rolling: controlling the temperature of the rolled piece when entering the finishing mill group and the linear speed of the rolled piece when exiting the finishing mill group; 5) And (3) cooling: and cooling the rolled piece after finish rolling by a multi-stage controlled cold water tank, then performing length-doubling shearing, and finally cooling by a cooling bed to obtain the high-strength anti-seismic steel bar with high strength-to-deflection ratio. According to the invention, through reasonable component design and control of billet heating and rolling processes, the yield strength is improved, and the tensile strength is improved at the same time, so that the high-strength anti-seismic steel bar with high strength-to-deflection ratio is obtained.
Description
Technical Field
The invention belongs to the technical field of high-strength steel bars, and particularly relates to a manufacturing method of a high-strength anti-seismic steel bar with high yield ratio.
Background
The high strength is the main direction of the development of the steel bar variety in China. The high-strength steel bar is used as one of important materials for construction, and the strength grade and the quality level of the high-strength steel bar have direct influence on saving resources and reducing energy consumption. The high-strength steel bar is used in the building, so that the steel consumption can be reduced, and the quality and the safety and reliability of the building can be improved; for example, the steel consumption can be reduced by about 14% when 500MPa is replaced by 400MPa, and the steel consumption can be reduced by about 8% when 600MPa is replaced by 500MPa, so that the method has very important significance for reducing the consumption of iron ore resources, reducing carbon dioxide emission and the like.
While the steel bars are developed to have high strength, the anti-seismic performance of the steel bars is also increasingly emphasized. The national seismic agency increases the earthquake resistance level of part of strong seismic belt house buildings from 7 to 9. The recovery and reconstruction regulations after earthquake disaster define the earthquake resistant requirement of the house building, and simultaneously, the requirement on earthquake resistant reinforcing steel bars for the building is also improved. The national construction department proposes that earthquake-resistant steel bars must be adopted for major construction projects, high-rise residential buildings and the like. The GB1499.2 steel bar standard for reinforced concrete issued by the national quality inspection general administration and the national standards committee together defines that the steel bar with a high-requirement anti-seismic structure should have high strength and plasticity, and one important embodiment index is that the ratio of the measured tensile strength to the measured yield strength (the strength-to-yield ratio) is not less than 1.25.
The shock resistance of the building reinforcing steel bars is also a high concern abroad, and relevant regulations are made in some building design specifications, such as New Zealand shock resistance design Specification, japanese New shock resistance design laws, american building shock resistance design provisional conditions, romania industry and civil building shock resistance design Specification, CEB-FIP concrete structure shock resistance Specification, israel building special load (earthquake) Specification and the like. One of the great common demands on the earthquake resistance of construction steel bars is that the demand for strong buckling is relatively high.
At present, the yield strength and the tensile strength of the high-strength steel bar are usually improved by adopting a fine grain strengthening mode, but the ratio of improving the yield strength by adopting the fine grain strengthening is higher than that of the tensile strength, so that the high-strength steel bar has the problem that the strength yield ratio cannot meet the standard requirement of the anti-seismic steel bar, the phenomenon is more obvious in the steel bar with higher strength, the production and the application of the high-strength steel bar are influenced, and the method is a technical problem faced in the field.
Disclosure of Invention
The invention aims to solve the technical problem of providing a manufacturing method of a high-strength anti-seismic steel bar with high yield ratio, which aims at the defects of the prior art, and the high-strength anti-seismic steel bar with high yield ratio is obtained by reasonably designing components and controlling the billet heating and rolling process while improving the yield strength.
In order to solve the technical problem, the invention provides a manufacturing method of a high-strength anti-seismic steel bar with high yield ratio, which comprises the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet enters a heating furnace to be heated in three sections of a preheating section, a heating section and a soaking section;
3) Rough rolling: the heated billet enters a rough rolling unit for rough rolling;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water and enters a finishing mill group for finish rolling;
5) And (3) cooling: and cooling the rolled piece after finish rolling by a multi-stage controlled cold water tank, then performing length-doubling shearing, and finally cooling by a cooling bed to obtain the high-strength anti-seismic steel bar with high strength-to-deflection ratio.
In the scheme, the temperature of the preheating section is 600-800 ℃, and the heating speed is 20-30 ℃/min.
In the scheme, the temperature of the heating section is 1140-1180 ℃, and the heating speed is 40-60 ℃/min.
In the scheme, the temperature of the soaking section is 1120-1160 ℃, and the heat preservation time is more than or equal to 30min.
In the scheme, the total heating time of the steel billet is 70-90min, and is controlled according to the temperature when the steel billet enters a heating furnace, and the total heating time is 80-90min when the temperature when the steel billet enters the heating furnace is less than or equal to 500 ℃; when the temperature of the billet entering the furnace is more than 500 ℃, the total heating time is 70-80min.
In the scheme, the temperature of the billet entering the roughing mill is 1040-1080 ℃.
In the scheme, the cooling speed of the through water cooling is 100-150 ℃/s.
In the scheme, the temperature of the rolled piece entering the finishing mill group is 950-1000 ℃.
In the scheme, the linear speed of the rolling stock out of the finishing mill group is less than or equal to 35m/s, the linear speed of the rolling stock with the specification of phi 12-16mm is 20-35m/s, the linear speed of the rolling stock with the specification of phi 18-22mm is 10-15m/s, and the linear speed of the rolling stock with the specification of phi 25-40mm is 5-8m/s.
In the scheme, the cooling speed of the multi-stage cooling control water tank is 10-30 ℃/s.
In the scheme, the temperature of the cooling bed on the rolled piece is 950-1000 ℃.
In the scheme, the high-strength anti-seismic steel bar with high strength-to-yield ratio comprises the following chemical components in percentage by weight: c:0.25-0.30%, si:0.25-0.45%, mn:1.20-1.40%, P: less than or equal to 0.045 percent, S: less than or equal to 0.045 percent, cr:0.05-0.40%, cu: less than or equal to 0.20 percent, ni: less than or equal to 0.20 percent, mo: less than or equal to 0.05 percent, al: less than or equal to 0.015 percent, V:0.06-0.13%, N:0.0130-0.0230%, and V/N is more than or equal to 4.5, and the balance is iron and unavoidable impurities.
In the scheme, the carbon equivalent CEV of the high-strength anti-seismic steel bar with high strength-to-buckling ratio is 0.50-0.57%, wherein CEV=C+Mn/6+ (Cr+Mo+V)/5+ (Cu+Ni)/15, and C and Mn, cr, mo, V, cu, ni are the mass percent of each element.
In the scheme, the yield strength of the high-strength anti-seismic steel bar with high yield ratio is 620-700MPa, the tensile strength is 780-900MPa, and the yield ratio is 1.26-1.29.
In the scheme, the microstructure of the high-strength anti-seismic steel bar with high strength-to-yield ratio is ferrite and pearlite, wherein the volume ratio of the pearlite is 45-55%.
In the scheme, the specification of the high-strength anti-seismic steel bar with high strength-to-deflection ratio is phi 12-40mm.
The technical scheme of the invention is mainly based on the following technical principles:
the proportion of ferrite (soft phase structure) and pearlite (hard phase structure) in the steel is reasonably controlled through the component C; the structure of the high-strength anti-seismic steel bar is mainly ferrite and pearlite structure, the yield strength of the high-strength anti-seismic steel bar depends on the yield strength of ferrite in steel, and the tensile strength of the high-strength anti-seismic steel bar depends on the tensile strength of pearlite in steel, so that the proportion of the hard pearlite phase structure in the steel reaches 45-50% through the component C, and the high-strength anti-seismic steel bar is favorable for greatly improving the strength-to-deflection ratio of the high-strength anti-seismic steel bar.
Meanwhile, from the reinforcing mechanism of steel, the reinforcing effect of C, si and Mn elements in the steel is mainly solid solution reinforcing, and the solid solution reinforcing effect is far lower than the effect of precipitation reinforcing, but the tensile strength is greatly improved by the solid solution reinforcing; from the structure of steel, the high-strength anti-seismic steel bar belongs to hypoeutectoid steel, and the improvement of C, mn element content is beneficial to improving the transformation of pearlite, so that the pearlite has good comprehensive performance and can greatly improve the tensile strength of the steel bar. Si can be dissolved in ferrite and austenite to improve the hardness and strength of steel, and the effect of Si is inferior to that of phosphorus and is stronger than elements such as manganese, nickel, chromium, tungsten, molybdenum, vanadium and the like. Therefore, properly increasing the content of Si element in the steel is beneficial to solid solution strengthening of the steel bar, and the tensile strength and the strength-to-deflection ratio are improved.
Ni is an element for strengthening ferrite, refining and increasing pearlite content, and can improve the fatigue performance of the high-strength steel bar and reduce notch sensitivity, so that the steel grade is added with a proper amount of Ni in the high-strength steel grade, and the strength is improved and the high yield ratio and the fatigue performance are improved.
Precipitation strengthening is an important strengthening mode of high-strength steel, and a proper amount of V, N is added to precipitate in the steel in the form of precipitation phases such as VN, VC, V (C, N) and the like, so that the yield strength and the tensile strength of the steel are improved. Because V has larger solubility in austenite, and the solid solution temperature is increased along with the increase of the content, a high-temperature long-time heating process is needed, so that VN, VC and V (C, N) are ensured to be fully solid-solved in the austenite, and conditions are created for the later rolling deformation precipitation and the post-rolling precipitation. Therefore, the invention adopts proper V, N content and high-temperature heating process, thereby ensuring enough precipitation strengthening effect, avoiding that excessive precipitation phases lead to grain refinement, leading the yield strength to be improved to be larger than the tensile strength and reducing the strength-to-deflection ratio. However, since the billet contains higher C, mn, cr, V, N, the heating brittleness transition temperature of the steel is reduced due to the elements, so that the heating temperature and the heating speed of the billet need to be strictly controlled, the billet is prevented from being cracked due to excessive stress caused by excessive heating speed in a preheating section, and the heating efficiency can be improved through rapid heating above the brittleness transition temperature, and the energy consumption is reduced. Meanwhile, the deformation rate of the steel bars has an important influence on the strong buckling ratio of the high-strength anti-seismic steel bars, the deformation rate of the high-strength anti-seismic steel bars is controlled by controlling rolling speeds of different specifications, austenite grains are prevented from being refined, and the strong buckling ratio of the high-strength anti-seismic steel bars is improved.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, through reasonable component design and control of billet heating and rolling processes, the yield strength is improved, and meanwhile, the tensile strength is improved, so that the high-strength anti-seismic steel bar with high strength-to-yield ratio is obtained, the yield strength is 620-700MPa, the tensile strength is 780-900MPa, and the strength-to-yield ratio is 1.26-1.29.
Detailed Description
For a better understanding of the present invention, the following examples are further illustrated, but are not limited to the following examples.
Example 1
Example 1 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, and the chemical components and weight percentage contents are as follows: c:0.25%, si:0.45%, mn:1.40%, P:0.025%, S:0.015%, cr:0.28%, cu:0.04%, ni:0.05%, mo:0.001%, al:0.005%, V:0.12%, N:0.021%, V/N5.7, CEV 0.57%, balance iron and unavoidable impurities.
The manufacturing method of the high-strength anti-seismic steel bar with high strength-to-yield ratio in embodiment 1 comprises the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and filled with 550 ℃ and enters a walking beam type heating furnace to be heated in three sections, the temperature of a preheating section is 800 ℃, and the heating speed is 30 ℃/min; the temperature of the heating section is 1140 ℃, and the heating speed is 40 ℃/min; soaking section temperature 1120 ℃, and heat preservation time 40min; the total heating time is 75min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1040 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water, the cooling speed is 150 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 950 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 12mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 32m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multistage control cold water tank at the cooling speed of 30 ℃/s, then shearing by multiple lengths, and finally cooling by a cooling bed at the temperature of 1000 ℃ to obtain the high-strength anti-seismic steel bar with high strength-to-deflection ratio.
Example 2
Example 2 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, and the chemical components and weight percentage contents are as follows: c:0.28%, si:0.35%, mn:1.20%, P:0.03%, S:0.017%, cr:0.15%, cu:0.05%, ni:0.04%, mo:0.003%, al:0.007%, V:0.10%, N:0.018%, V/N5.6, CEV 0.54%, balance iron and unavoidable impurities.
Example 2 a method for manufacturing a high strength anti-seismic rebar with a high strength to deflection ratio, comprising the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and is fed into a walking beam type heating furnace at 400 ℃ to be heated in three sections, the temperature of a preheating section is 650 ℃, and the heating speed is 25 ℃/min; the temperature of the heating section is 1160 ℃, and the heating speed is 60 ℃/min; the soaking section temperature is 1140 ℃, and the heat preservation time is 55min; the total heating time is 85min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1050 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water, the cooling speed is 145 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 980 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 18mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 10m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multi-stage cold water control tank at a cooling speed of 26 ℃/s, then performing double-length shearing, and finally cooling by a cooling bed at a temperature of 980 ℃ to obtain the high-strength anti-seismic steel bar with high yield ratio.
Example 3
Example 3 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, and the chemical components and weight percentage contents are as follows: c:0.26%, si:0.4%, mn:1.30%, P:0.021%, S:0.017%, cr:0.3%, cu:0.05%, ni:0.04%, mo:0.002%, al:0.004%, V:0.13%, N:0.023%, V/N5.7, CEV 0.57%, balance iron and unavoidable impurities.
Example 3 a method for manufacturing a high strength anti-seismic rebar with a high strength to deflection ratio, comprising the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and filled with 550 ℃ and enters a walking beam type heating furnace to be heated in three sections, the temperature of a preheating section is 750 ℃, and the heating speed is 28 ℃/min; the temperature of the heating section is 1180 ℃, and the heating speed is 55 ℃/min; soaking section temperature 1160 ℃, and heat preservation time 50min; the total heating time is 72min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1060 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water, the cooling speed is 140 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 960 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 32mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 6.5m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multi-stage cold water control tank at a cooling speed of 15 ℃/s, then performing double-length shearing, finally cooling by a cooling bed, and obtaining the high-strength anti-seismic steel bar with high strength-to-deflection ratio at a temperature of 950 ℃.
Example 4
Example 4 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, wherein the chemical components and the weight percentage content are as follows: c:0.3%, si:0.25%, mn:1.25%, P:0.024%, S:0.01%, cr:0.15%, cu:0.04%, ni:0.05%, mo:0.004%, al:0.005%, V:0.06%, N:0.013%, V/N4.6, CEV 0.56%, balance iron and unavoidable impurities.
Example 4 method for manufacturing high strength and buckling ratio high strength anti-seismic steel bars, comprising the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and is fed into a walking beam type heating furnace at 580 ℃ for three-stage heating, the preheating stage temperature is 780 ℃, and the heating speed is 25 ℃/min; the temperature of the heating section is 1160 ℃, and the heating speed is 50 ℃/min; the soaking section temperature is 1150 ℃, and the heat preservation time is 35min; the total heating time is 70min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1080 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing through water, the cooling speed is 135 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 980 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 28mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 7.5m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multi-stage cold water control tank at a cooling speed of 16 ℃/s, then performing double-length shearing, and finally cooling by a cooling bed at a temperature of 960 ℃ to obtain the high-strength anti-seismic steel bar with high yield ratio.
Example 5
Example 5 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, and the chemical components and weight percentage contents are as follows: c:0.265%, si:0.38%, mn:1.21%, P:0.028%, S:0.02%, cr:0.4%, cu:0.07%, ni:0.02%, mo:0.001%, al:0.001%, V:0.11%, N:0.018%, V/N6.1, CEV 0.57%, balance iron and unavoidable inclusions.
The method for manufacturing the high-strength anti-seismic steel bar with high strength-to-yield ratio in embodiment 5 comprises the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and is fed into a walking beam type heating furnace at 520 ℃ for three-stage heating, the preheating stage temperature is 680 ℃, and the heating speed is 22 ℃/min; the temperature of the heating section is 1150 ℃, and the heating speed is 50 ℃/min; the soaking section temperature is 1130 ℃, and the heat preservation time is 40min; the total heating time is 77min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1060 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water, the cooling speed is 115 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 970 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 20mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 10.5m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multi-stage cold water control tank at a cooling speed of 15 ℃/s, then performing double-length shearing, finally cooling by a cooling bed, and obtaining the high-strength anti-seismic steel bar with high strength-to-deflection ratio at a temperature of 950 ℃.
Example 6
Example 6 a high strength anti-seismic steel bar with high strength-to-buckling ratio is prepared, wherein the chemical components and the weight percentage content are as follows: c:0.26%, si:0.4%, mn:1.38%, P:0.017%, S:0.01%, cr:0.05%, cu:0.03%, ni:0.05%, mo:0.004%, al:0.006%, V:0.095%, N:0.018%, V/N5.3, CEV 0.53%, balance iron and unavoidable impurities.
Example 6 method for manufacturing high strength and buckling ratio high strength anti-seismic steel bars, comprising the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and is filled with 380 ℃ and enters a walking beam type heating furnace to be heated in three sections, the temperature of a preheating section is 600 ℃, and the heating speed is 20 ℃/min; the temperature of the heating section is 1140 ℃ and the heating speed is 45 ℃/min; soaking section temperature 1120 ℃, and preserving heat for 50min; the total heating time is 85min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1080 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing through water, the cooling speed is 120 ℃/s, the rolled piece enters a finishing mill group for finish rolling, and the temperature is 980 ℃ when entering the finishing mill group; the specification of the rolled piece is that the diameter phi is 14mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 22m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multistage control cold water tank at a cooling speed of 18 ℃/s, then performing double-length shearing, and finally cooling by a cooling bed at a temperature of 950 ℃ to obtain the high-strength anti-seismic steel bar with high yield ratio.
Comparative example 1
Comparative example 1 a high-strength anti-seismic steel bar is prepared, and comprises the following chemical components in percentage by weight: c:0.23%, si:0.5%, mn:1.55%, P:0.025%, S:0.03%, cr:0.02%, cu:0.08%, ni:0.03%, mo:0.003%, al:0.001%, V:0.17%, N:0.025%, V/N6.8, CEV 0.53%, balance iron and unavoidable impurities.
The manufacturing method of the high-strength anti-seismic steel bar of comparative example 1 comprises the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and filled with 550 ℃ and enters a walking beam type heating furnace to be heated in three sections, the temperature of a preheating section is 900 ℃, and the heating speed is 35 ℃/min; the temperature of the heating section is 1250 ℃, and the heating speed is 35 ℃/min; soaking section temperature 1250 ℃ and heat preservation time 25min; the total heating time is 60min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1100 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: feeding the rolled piece after rough rolling into a finishing mill group for finish rolling, wherein the temperature of the rolled piece after rough rolling is 1150 ℃; the specification of the rolled piece is that the diameter phi is 25mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 8m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multistage control cold water tank at a cooling speed of 40 ℃/s, then shearing by multiple lengths, and finally cooling by a cooling bed at a temperature of 920 ℃ to obtain the high-strength anti-seismic steel bar.
Comparative example 2
Comparative example 2 a high-strength anti-seismic steel bar is prepared, and comprises the following chemical components in percentage by weight: c:0.25%, si:0.6%, mn:1.5%, P:0.035%, S:0.02%, cr:0.03%, cu:0.03%, ni:0.02%, mo:0.006%, al:0.002%, V:0.15%, N:0.02%, V/N7.5, CEV 0.54%, balance iron and unavoidable impurities.
The manufacturing method of the high-strength anti-seismic steel bar of comparative example 2 comprises the following steps:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet is heated by hot feeding and filled with 550 ℃ and enters a walking beam type heating furnace to be heated in three sections, the temperature of a preheating section is 850 ℃, and the heating speed is 40 ℃/min; the temperature of the heating section is 1230 ℃, and the heating speed is 40 ℃/min; soaking section temperature 1230 ℃, and preserving heat for 20min; the total heating time is 55min;
3) Rough rolling: feeding the heated billet into a rough rolling unit for rough rolling, wherein the temperature is 1090 ℃ when the billet enters the rough rolling unit;
4) Finish rolling: feeding the rolled piece after rough rolling into a finishing mill group for finish rolling, wherein the temperature of the rolled piece after rough rolling is 1120 ℃ when fed into the finishing mill group; the specification of the rolled piece is that the diameter phi is 18mm when the rolled piece goes out of the finishing mill group, and the linear speed of the finishing mill group is 12m/s;
5) And (3) cooling: and (3) cooling the rolled piece after finish rolling by a multistage control cold water tank at a cooling speed of 55 ℃/s, then shearing by multiple lengths, and finally cooling by a cooling bed at a temperature of 850 ℃ to obtain the high-strength anti-seismic steel bar.
The properties of the high-strength anti-seismic bars prepared in examples 1 to 6 and comparative examples 1 to 2 are shown in Table 1.
TABLE 1
As can be seen from table 1, the embodiment of the invention improves the proportion of pearlite in steel through reasonable component design and control of billet heating and rolling process, and improves the yield strength and the tensile strength at the same time, thereby obtaining the high-strength anti-seismic steel bar with high strength-to-deflection ratio; the steel bars of the comparative examples, however, have lower yield strength and lower tensile strength than those of the examples, and in particular, the strength to deflection ratio does not meet the performance requirements.
The above examples are presented for clarity of illustration only and are not limiting of the embodiments. Other variations or modifications of the above description will be apparent to those of ordinary skill in the art, and it is not necessary or exhaustive of all embodiments, and thus all obvious variations or modifications that come within the scope of the invention are desired to be protected.
Claims (10)
1. The manufacturing method of the high-strength anti-seismic steel bar with high yield ratio is characterized by comprising the following steps of:
1) Smelting a casting blank: molten steel is smelted by a converter and is continuously cast into billets;
2) Heating a steel billet: the billet enters a heating furnace to be heated in three sections, the temperature of a preheating section is 600-800 ℃, the temperature of a heating section is 1140-1180 ℃, the temperature of a soaking section is 1120-1160 ℃, the heat preservation time of the soaking section is more than or equal to 30min, and the total heating time is 70-90min;
3) Rough rolling: the heated billet enters a rough rolling unit for rough rolling, and the temperature of the billet entering the rough rolling unit is 1040-1080 ℃;
4) Finish rolling: the rolled piece after rough rolling is cooled by passing water and enters a finishing mill group for finish rolling, the temperature of the rolled piece entering the finishing mill group is 950-1000 ℃, and the linear speed of the rolled piece exiting the finishing mill group is less than or equal to 35m/s;
5) And (3) cooling: and cooling the rolled piece after finish rolling by a multi-stage controlled cold water tank, then performing length-doubling shearing, and finally cooling by a cooling bed to obtain the high-strength anti-seismic steel bar with high strength-to-deflection ratio.
2. The method for manufacturing a high strength and vibration resistant steel bar according to claim 1, wherein the heating speed of the preheating section is 20-30 ℃/min, and the heating speed of the heating section is 40-60 ℃/min.
3. The method for manufacturing high-strength and earthquake-resistant steel bars with high yield ratio according to claim 1, wherein the total heating time is controlled according to the temperature when the steel billet enters the heating furnace, and the total heating time is 80-90min when the steel billet enters the heating furnace at the temperature of less than or equal to 500 ℃; when the temperature of the billet entering the furnace is more than 500 ℃, the total heating time is 70-80min.
4. The method for manufacturing high-strength and earthquake-resistant steel bars with high strength and deflection ratio according to claim 1, wherein the linear velocity of the rolling mill group is controlled according to the rolling stock specification, the rolling stock linear velocity with the specification of phi 12-16mm is 20-35m/s, the rolling stock linear velocity with the specification of phi 18-22mm is 10-15m/s, and the rolling stock linear velocity with the specification of phi 25-40mm is 5-8m/s.
5. The method for manufacturing a high strength and elongation steel bar according to claim 1, wherein the cooling rate of the through water cooling is 100-150 ℃/s.
6. The method for manufacturing high strength and vibration resistant steel according to claim 1, wherein the cooling rate of the multistage cooling water tank is 10-30 ℃/s.
7. The method for manufacturing high strength-to-buckling ratio high strength anti-seismic steel according to claim 1, wherein the cooling bed temperature on the rolled piece is 950-1000 ℃.
8. The method for manufacturing high-strength anti-seismic steel bars with high yield ratio according to claim 1, wherein the high-strength anti-seismic steel bars with high yield ratio comprise the following chemical components in percentage by weight: c:0.25-0.30%, si:0.25-0.45%, mn:1.20-1.40%, P: less than or equal to 0.045 percent, S: less than or equal to 0.045 percent, cr:0.05-0.40%, cu: less than or equal to 0.20 percent, ni: less than or equal to 0.20 percent, mo: less than or equal to 0.05 percent, al: less than or equal to 0.015 percent, V:0.06-0.13%, N:0.0130-0.0230%, V/N not less than 4.5, CEV 0.50-0.57%, and iron and unavoidable impurities as the rest.
9. The method for manufacturing a high strength-to-yield ratio steel bar according to claim 1, wherein the yield strength of the high strength-to-yield ratio steel bar is 620-700MPa, the tensile strength is 780-900MPa, and the yield ratio is 1.26-1.29.
10. The method for manufacturing a high strength-to-buckling ratio high strength anti-seismic steel according to claim 1, wherein the microstructure of the high strength-to-buckling ratio high strength anti-seismic steel is ferrite and pearlite, and wherein the volume ratio of pearlite is 45-55%.
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