CN117488053A - Recovery method of straightening bar Agt of high-ductility cold-rolled ribbed steel bar - Google Patents
Recovery method of straightening bar Agt of high-ductility cold-rolled ribbed steel bar Download PDFInfo
- Publication number
- CN117488053A CN117488053A CN202311388767.1A CN202311388767A CN117488053A CN 117488053 A CN117488053 A CN 117488053A CN 202311388767 A CN202311388767 A CN 202311388767A CN 117488053 A CN117488053 A CN 117488053A
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- China
- Prior art keywords
- steel bar
- bar
- rolled ribbed
- agt
- heat treatment
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 47
- 239000010959 steel Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000011084 recovery Methods 0.000 title claims description 9
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 238000001816 cooling Methods 0.000 claims abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000003466 welding Methods 0.000 abstract description 4
- 238000001514 detection method Methods 0.000 abstract 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 9
- 238000010276 construction Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 206010035148 Plague Diseases 0.000 description 1
- 241000607479 Yersinia pestis Species 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
Classifications
-
- 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
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to a method for recovering straightening ribs Agt of high-ductility cold-rolled ribbed steel bars, which comprises the steps of placing the straightened high-ductility cold-rolled ribbed steel bars in a heat treatment furnace for heat treatment, heating to 472-488 ℃, preserving heat for 3h, and cooling to normal temperature along with the furnace. The steel bars obtained by the method are used for welding to manufacture the steel bar welded mesh, the Agt performance index of the steel bar detection sample can meet the national standard requirements, and the practical problem faced in production is solved.
Description
Technical Field
The invention belongs to the technical field of steel bar treatment for reinforced concrete, and particularly relates to a recovery method of a high-ductility cold-rolled ribbed steel bar straightening bar Agt.
Background
The steel bar welded mesh is defined in the 3 rd part of the steel bar welded mesh for reinforced concrete of the national standard GB/T1499.3-2022, and the adopted steel bars are defined as follows: CRB550 cold-rolled ribbed steel bar and CRB600H high-ductility cold-rolled ribbed steel bar which meet the national standard GB/T13788 specification; hot rolled plain round bar according with the specification of the national standard GB/T1499.1; the ribbed steel bar meets the national standard BG/T1499.2. The performance requirements of the reinforcing steel bar welded mesh in the national standard GB/T1799.3-2022 are also specified explicitly, and the mechanical and technological properties of the reinforcing steel bar of the welded mesh are required to respectively accord with the specifications of reinforcing steel bars of corresponding brands in corresponding standards, and the inspected samples are all intercepted from the finished mesh.
When the cold rolled ribbed steel bar with the diameter of less than 14mm is adopted to manufacture the steel bar welded mesh, the adopted raw materials are coiled steel bars, and the coiled steel bars are convenient to store and transport. Before the reinforcing mesh is welded, the coiled reinforcing steel bars are required to be straightened, then the straightened reinforcing steel bars are cut into longitudinal reinforcing steel bars and transverse reinforcing steel bars which meet the construction requirements, and the longitudinal reinforcing steel bars and the transverse reinforcing steel bars are respectively arranged at a certain interval and welded into meshes at right angles.
The problems faced by the inventors are: the relevant performance of the purchased coiled steel bars accords with the national standard GB/T13788, but the phenomenon that the maximum total elongation (Agt) is unqualified often occurs when the quality inspection sample taken from the welded steel bar welding net is subjected to performance quality inspection. This difficulty not only plagues the inventors but also prevents the normal production of the welded mesh of rebar.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a recovery method of a straightening rib Agt of a high-ductility cold-rolled ribbed steel bar.
The technical scheme of the invention is as follows:
a method for recovering the straightening rib Agt of the high-ductility cold-rolled ribbed steel bar includes such steps as heat treating the straightened ribbed steel bar in a heat treating furnace, heating to 472-488 deg.C, holding the temp for 3 hr, and cooling to ordinary temp.
Further, the uniformity of the furnace temperature of the heat treatment furnace is +/-10 ℃, and the temperature control precision is +/-1 ℃.
Further, the heat treatment furnace is a resistance furnace.
The invention has the following beneficial effects: the heat treatment of ' heating to 472-488 ℃ and then preserving heat for 3 hours ' is carried out on the straightened cold rolled ribbed steel bar, and then cooling to normal temperature along with a furnace ' changes the state of lattice distortion in the microstructure of the steel bar, and refines the grain size, so that the Agt performance index meets the national standard requirement, and the actual problem faced in production is solved.
Drawings
Fig. 1 is a metallurgical structure of a cold rolled ribbed bar in a coiled state.
Fig. 2 is a metallurgical structure of the cold rolled ribbed bar after alignment.
Fig. 3 is a metallurgical structure of the cold rolled ribbed bar after heat treatment.
Detailed Description
The invention will be described in further detail with reference to the drawings and the detailed description.
A recovery method of a high-ductility cold-rolled ribbed steel bar straightening bar Agt comprises the following steps:
s1: the cold rolled ribbed steel bar in a coiled state is straightened by adopting a mechanical straightening method, wherein the diameter of the cold rolled ribbed steel bar is 10mm, and the cold rolled ribbed steel bar meets CRB600H high-ductility cold rolled ribbed steel bar specified by national standard GB/T13788, and the related performance indexes are shown in the following table 1:
s2: cutting the straightened cold rolled ribbed steel bar into steel bar segments meeting the construction size requirement.
S3: placing the steel bar segments into a heat treatment furnace for heat treatment: the heat treatment furnace specifically adopts a trolley type resistance furnace, the uniformity of the furnace temperature is +/-10 ℃, and the temperature control precision is +/-1 ℃; heating to 480+/-8 ℃, preserving heat for 3 hours, and cooling to normal temperature along with a furnace.
The cold rolled ribbed steel bars obtained by the pretreatment method are respectively arranged at a certain interval, the longitudinal steel bars and the transverse steel bars are mutually right-angled, and all the crossing points are welded together by a resistance welding method to form a steel bar welding net.
From the above, the maximum total force extension rate (Agt) after heat treatment is not less than 5.0, and meets the national standard requirement.
And (3) respectively checking microstructures of the cold rolled ribbed steel bar in a coiled state, the straightened cold rolled ribbed steel bar and the heat-treated cold rolled ribbed steel bar by adopting a metallographic microscope, wherein the magnification factor is 500X under the metallographic microscope, and the tissue morphology is respectively shown in figures 1, 2 and 3.
The coiled steel bar is subjected to straightening treatment, then the steel bar is subjected to cold deformation, the metallographic structure is a ferrite and pearlite structure, sliding and dislocation occur among grains, the change of the shapes of the grains, the elongation and the flattening phenomena occur, the longitudinal fiberization phenomenon occurs, the sliding resistance is increased due to lattice distortion, the plastic deformation resistance of the metal is increased, namely the strength and the hardness are slightly improved, the plasticity and the toughness are obviously reduced, so that the Agt performance index is reduced, and the work hardening phenomenon occurs.
The metallographic structure of the steel bar after heat treatment is a ferrite and pearlite structure, and compared with the steel bar after straightening and before heat treatment, the optical microstructure is not obviously changed, the grains are recombined, the shape of the grains is changed, the recovery phenomenon exists, the grain size is thinned, and therefore the Agt performance index meets the national standard requirement.
Claims (3)
1. A recovery method of a high-ductility cold-rolled ribbed steel bar straightening bar Agt is characterized by comprising the following steps: and (3) placing the straightened high-ductility cold-rolled ribbed steel bar into a heat treatment furnace for heat treatment, heating to 472-488 ℃, preserving heat for 3 hours, and then cooling to normal temperature along with the furnace.
2. The recovery method of the high-ductility cold-rolled ribbed bar alignment bar Agt according to claim 1, characterized by: the uniformity of the furnace temperature of the heat treatment furnace is +/-10 ℃, and the temperature control precision is +/-1 ℃.
3. The recovery method of the high-ductility cold-rolled ribbed bar alignment bar Agt according to claim 1, characterized by: the heat treatment furnace is a resistance furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311388767.1A CN117488053B (en) | 2023-10-25 | 2023-10-25 | Recovery method of straightening bar Agt of high-ductility cold-rolled ribbed steel bar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311388767.1A CN117488053B (en) | 2023-10-25 | 2023-10-25 | Recovery method of straightening bar Agt of high-ductility cold-rolled ribbed steel bar |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117488053A true CN117488053A (en) | 2024-02-02 |
| CN117488053B CN117488053B (en) | 2024-11-01 |
Family
ID=89668096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311388767.1A Active CN117488053B (en) | 2023-10-25 | 2023-10-25 | Recovery method of straightening bar Agt of high-ductility cold-rolled ribbed steel bar |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117488053B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102212667A (en) * | 2011-05-05 | 2011-10-12 | 安阳市合力高速冷轧有限公司 | Production process of high-ductility cold-rolled ribbed steel bars |
| US20120222777A1 (en) * | 2009-11-25 | 2012-09-06 | Tata Steel Ijmuiden B.V. | Process to manufacture grain-oriented electrical steel strip and grain-oriented electrical steel produced thereby |
| CN112239830A (en) * | 2020-08-31 | 2021-01-19 | 盐城市联鑫钢铁有限公司 | Low-cost high-ductility disc strip for CRB600H and rolling process thereof |
| WO2022151603A1 (en) * | 2021-01-15 | 2022-07-21 | 江苏省沙钢钢铁研究院有限公司 | 400 mpa-grade corrosion-resistant steel bar and production method therefor |
-
2023
- 2023-10-25 CN CN202311388767.1A patent/CN117488053B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120222777A1 (en) * | 2009-11-25 | 2012-09-06 | Tata Steel Ijmuiden B.V. | Process to manufacture grain-oriented electrical steel strip and grain-oriented electrical steel produced thereby |
| CN102212667A (en) * | 2011-05-05 | 2011-10-12 | 安阳市合力高速冷轧有限公司 | Production process of high-ductility cold-rolled ribbed steel bars |
| CN112239830A (en) * | 2020-08-31 | 2021-01-19 | 盐城市联鑫钢铁有限公司 | Low-cost high-ductility disc strip for CRB600H and rolling process thereof |
| WO2022151603A1 (en) * | 2021-01-15 | 2022-07-21 | 江苏省沙钢钢铁研究院有限公司 | 400 mpa-grade corrosion-resistant steel bar and production method therefor |
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| Publication number | Publication date |
|---|---|
| CN117488053B (en) | 2024-11-01 |
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