CN1586750A - Rolling method for low carbon twisted steel bar - Google Patents
Rolling method for low carbon twisted steel bar Download PDFInfo
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- CN1586750A CN1586750A CN 200410070096 CN200410070096A CN1586750A CN 1586750 A CN1586750 A CN 1586750A CN 200410070096 CN200410070096 CN 200410070096 CN 200410070096 A CN200410070096 A CN 200410070096A CN 1586750 A CN1586750 A CN 1586750A
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Abstract
The present invention relates to metal rolling technology, and especially the rolling process of twisted low carbon steel bar. The twisted low carbon steel bar has the chemical components of: C 0.17-0.23 wt%, Si 0.20-0.80 wt%, Mn 0.50-1.50 wt%, S not more than 0.035 wt% and P not more than 0.035 wt%. The rolling process with complete or patial temperature control includes the following steps: initial rolling with low temperature cogging at 850-950 deg.c, middle rolling at 750-850 deg.c with accumulated deformation over 50 %, finish rolling at 750-900 deg.c, and subsequent water cooling at lower than 600 deg.c with cooling speed greater than 10 deg.c/sec. Compared with available technology, the present invention has superfine crystal grain structure and high steel bar performance.
Description
Technical field
The invention belongs to metal rolled field, relate generally to the milling method of low carbon steel twisted steel.
Background technology
In the prior art, the patent of invention that the inventor herein has obtained the authorization on May 14th, 2003, the patent No. is 00109495.5, this patent is the production of the ultra-fine grain reinforcing bar that carries out according to the steel rolling process that the chemical composition of straight carbon steel Q235 and this patent inventor formulate, but its finished product can not satisfy the III grade reinforcing steel tensile strength sigma of stipulating among the GB1499-1998 fully
bGreater than 570Mpa and the IV grade reinforcing steel tensile strength regulation greater than 630MPa, and its actual measurement strong flexor ratio can not reach the regulation greater than 1.25.Therefore, in the face of the needs of the upgrading of reinforcing bar kind, be necessary to establish the chemical composition system of brand-new reinforcing bar, bar and steel rolling process system with the regulation that satisfies present national standard (GB1499) require with.
Summary of the invention
The objective of the invention is to provide the milling method of preparation ultra-fine grain reinforcing bar, its performance is satisfied among the GB1499 III, the every index of IV grade reinforcing steel at low carbon steel twisted steel.
The present invention is that the application by the novel technique of steel grade optimization and original creation makes modern steel enterprise line bar continuous rolling unit replace microalloying or low alloying steel production yield strength at the reinforcing bar of 400-500MPaIII, IV level with straight carbon steel, makes its performance satisfy every index of standard GB 1499-1998 " armored concrete hot rolled ribbed steel bar " fully.Its mechanism is: make rod, wire rod obtain crystallite dimension fine grained texture between 3-10 μ m by the mechanism of mechanically deform and temperature control comprehensive utilization austenite dynamic recrystallization, static crystallization again, non-recrystallization deformation, deformation induced ferrite transformation and ferrite dynamic recrystallization in the operation of rolling.Core technology is the actual features according to factory's line production line of bar, according to above-mentioned deformation mechanism, whole process or part of generating units temperature control are taked in steel rolling production, realized ultra-fineization of excellent wire rod microstructure and reach III, the IV grade reinforcing steel national standard of yield strength for 400-500MPa according to the different Physical Metallurgy mechanism of actual production parameter utilization are final.In order to reach the purpose of whole process temperature control, need increase water cooling plant between the tandem rolling frame and between unit and the equipment of mill capacity deficiency increased transformations such as power of motor.
According to above-mentioned purpose and working mechanism, solution of the present invention is the composition with general structural carbon steel, it is carried out optimization of Chemical Composition, comprehensive utilization austenite recrystallization, non-recrystallization and deformation induced phase transformation theory reach the technology of rolling the back water-cooled by control cold-peace between frame, finally obtain desired product tissue and performance.
The concrete solution of the present invention is: need adjust and optimize straight carbon steel Q235 type chemical composition by present domestic III, IV grade reinforcing steel standard, make it can obtain ultra-fine grain and the qualified spiral of performance in rolling process.The present invention adopts the concrete chemical composition of steel grade to be: C0.17-0.23%, Si0.20-0.80%, Mn0.50-1.50%, S≤0.035%, P≤0.035%.
According to reinforcing bar steel rolling produce thick, in, the characteristics of finish rolling take following production technology respectively:
(1) rough rolling step takes the low temperature open rolling to utilize the slow-footed characteristics of this stage rolling simultaneously, rolling temperature is controlled between 850-950 ℃, utilize the broken strand of zerolling columanar structure, inner open texture of seam strand and the controlled rolling of realization austenite recrystallization, guaranteeing austenite crystal relatively in tinyization, the steel dense internal organizationization.(2) in, the rolling temperature of some milling trains is controlled between the 750-900 ℃ of temperature in the mm finishing mill unit, guarantee that simultaneously tandem mill accumulative total deflection is controlled at greater than 50%, be implemented in austenite in the operation of rolling to ferritic transformation ferrite generation simultaneously dynamic recrystallization, thus the ultra-fine ultra-fine ferrite crystal grain of axle such as acquisition.To roll the back grain growth in order controlling, need to wear water cooling to 600 ℃ following temperature, wear coolant-temperature gage by difference simultaneously and finally control microstructure.
The foundation of above-mentioned concrete technical scheme is:
One, optimizing components: reduce production costs by control C, Mn, Si content, increase economic efficiency, so our purpose is only with the composition of structural carbon steel, it is carried out optimizing components, its yield strength is brought up to more than the 500MPa.C, Mn, Si have in various degree invigoration effect to the performance of steel, and Mn, Si have very high solution strengthening ability, C except that the solution strengthening ability is arranged, thereby also determine the content of second tissue to influence performance.Under the prerequisite that satisfies reinforcing bar chemical composition national standard, in the composition range of structural carbon steel, optimize the content of setting element, mainly be to solve the low excessively problem of strong flexor ratio in order to improve tensile strength, because concern according to Hall-Petch, crystallite dimension is thin more, and yield strength and tensile strength will be approaching more, and strong flexor ratio will be low more.
Two, technology controlling and process, according to bar materials on continuous rolling mill mill speed height, temperature rise is difficult for the cooling characteristics soon, need forced cooling, the 2nd, mill speed is fast, pass deformation is little, is unfavorable for utilizing large deformation to produce deformation induced ferrite transformation and obtains fine grained texture, therefore needs to pay attention to the accumulative total deformation effect.
Therefore, at first will reduce start rolling temperature, the benefit of doing like this is that the temperature that one can reduce heating furnace is saved the energy, reduces energy consumption, reduced cost.It two can be so that austenitic crystallite dimension be difficult for too growing up, thereby helps grain refinement, so the start rolling temperature that we select is between 850-950 ℃.Secondly we are increasing water cooling plant between unit or between each frame of middle milling train group, mm finishing mill unit, purpose realizes that by the cooling means crystallization again and the non-recrystallization of structural carbon steel are rolling, thereby refine austenite crystal grain and control austenite crystal are unlikely to too to grow up.We studies show that, under the high-speed rolling condition, straight carbon steel can realize that non-recrystallization is rolling, sees accompanying drawing 2.Accompanying drawing 2 has provided the deformation parameter interval of dynamic recrystallization, non-recrystallization and the deformation induced ferrite transformation of the straight carbon steel Q235 after optimizing under the high speed deformation condition.
In, continuation water-cooled between mm finishing mill unit, in making, the temperature of finish rolling rolling temperature is reduced to 750-900 ℃, guarantee passage accumulative total deflection greater than 60% this temperature range planted agent, and should lower the temperature continuously in the operation of rolling, and finally be in A
E3-A
R3Passage cumulative deformation between the temperature is greater than 50%, A
E3And A
R3Value should specifically determine according to concrete chemical composition of steel and steel rolling process parameter.Use non-recrystallization distortion, deformation induced ferrite transformation and ferrite dynamic recrystallization mechanism, will make the deformation austenite crystal induce more tiny voxel volume, and change very fast, crystallite dimension≤10 μ m.That carries out fair speed subsequently wears water cooling 〉=10 ℃/S, is cooled to 400-600 ℃, goes up the cold bed air cooling then, guarantees the final crystallite dimension≤10 μ m of product, and normal temperature undertissue is ferrite and pearlitic structrure, does not get rid of the bainite that minute quantity is arranged.
Satisfy the crystallite dimension size of the comprehensive mechanical performance reinforcing bar of GB for final assurance acquisition, can regulate with the different of steel rolling production technology according to the difference of the chemical composition of reinforcing bar, its basic principle is: (1) is if the rolling power deficiency of milling train, and the control cooling infrastructure does not match, can select the chemical composition of high level for use, crystallite dimension can be controlled suitable increase.(2) for the supporting production unit of the sufficient cooling device of various rolling powers, can reduce chemical composition content, control more tiny crystallite dimension.Above-mentioned basic principle can realize that a steel is multistage, the purpose of many steel peer.The reinforcing bar that the present invention compared with prior art prepares has the structure of ultra-fine grain, and the performance of its reinforcing bar reaches among the GB1499 III, the every index of IV grade reinforcing steel, finally can guarantee for III grade reinforcing steel yield strength σ
s〉=400MPa, tensile strength sigma
b〉=570MPa, δ
5〉=20%, strong flexor ratio is greater than 1.25.For IV grade reinforcing steel yield strength σ
s〉=500MPa, tensile strength sigma
b〉=630MPa, δ
5〉=20%, strong flexor ratio is greater than 1.25, and its production qualification rate can reach the ordinary production level.
Description of drawings
Accompanying drawing 1 is the metallographic structure figure of the ultra-fine brilliant low-carbon screw thread reinforcing bar of the present invention.
Accompanying drawing 2 has provided the high speed deformation condition deformation parameter interval of dynamic recrystallization, non-recrystallization and the deformation induced ferrite transformation of optimization back straight carbon steel Q235 down.
The specific embodiment
Adopt the production method of the present invention of composition of the low carbon steel twisted steel Q235 of described optimization, produced three batches of low carbon steel twisted steels, three grades of steel that lot number adopted and chemical composition are as shown in table 1.When rolling billet heating temperature and rolling temperature, total deformation and roll the back cooling velocity as shown in table 2.Rolling and the cooling after, sampling and measuring tensile property and ferrite grain size, its result is as shown in table 3.In order to contrast the 1 crowd of low-carbon screw thread reinforcing bar Q235 that adopts prior art to produce, 1 grade of steel that lot number adopted and chemical composition, technological parameter, performance are together listed in table 1, table 2, table 3.Wherein sequence number 1-3# is the Q235 embodiment of the present invention's optimization, and wherein the embodiment of 1-2# reaches the national standard of III grade reinforcing steel.3# reaches the national standard of IV grade reinforcing steel.4# is a prior art Q235 Comparative Examples.
Selected steel grades 0.21%C-0.40%Si-0.79%Mn, 950 ℃ of start rolling temperatures, with the inter-stand cooling temperature control, going out the finishing mill temperature is 840 ℃ between middle mm finishing mill unit, then the cooling rate with 〉=10 ℃/S is as cold as 600 ℃.Obtain yield strength average out to σ
s=460Mpa, tensile strength sigma
b=630Mpa, percentage elongation=22.5%, strong flexor ratio σ
b/ σ
s=1.36, be organized as ferrite+pearlite, ferrite grain size is 10 μ m, pearlitic grain size 7 μ m.Performance reaches the national standard of III grade reinforcing steel.
Embodiment 2
Selected steel grades 0.22%C-0.35%Si-0.60%Mn, 950 ℃ of start rolling temperatures, with the inter-stand cooling temperature control, going out the finishing mill temperature is 850 ℃ between middle mm finishing mill unit, then the cooling rate with 〉=10 ℃/S is as cold as 550 ℃.Obtain yield strength average out to σ
s=450Mpa, tensile strength sigma
b=610Mpa, percentage elongation=25%, strong flexor ratio σ
b/ σ
s=1.35, be organized as ferrite+pearlite, ferrite grain size is 8 μ m, pearlitic grain size 5 μ m.Performance reaches the national standard of III grade reinforcing steel.
Embodiment 3
Selected steel grades 0.21%C-0.53%Si-0.8%Mn, 920 ℃ of start rolling temperatures, with the inter-stand cooling temperature control, going out the finishing mill temperature is 830 ℃ between middle mm finishing mill unit, then the cooling rate with 〉=10 ℃/S is as cold as 500 ℃.Obtain yield strength average out to σ
s=520Mpa, tensile strength sigma
b=660Mpa, percentage elongation=22%, strong flexor ratio σ
b/ σ
s=1.26, be organized as ferrite+pearlite, ferrite grain size is 7.5 μ m, pearlitic grain size 5 μ m.Performance reaches the national standard of IV grade reinforcing steel.
The chemical composition of table 1 embodiment low carbon steel twisted steel is compared with the prior art table (wt%)
| Lot number | Chemical composition (wt%) | ||||
| ????C | ????Si | ????Mn | ????P | ?S | |
| ????1 | ????0.21 | ????0.40 | ????0.79 | ????0.03 | ?0.015 |
| ????2 | ????0.22 | ????0.35 | ????0.60 | ????0.026 | ?0.015 |
| ????3 | ????0.22 | ????0.53 | ????0.80 | ????0.026 | ?0.015 |
| ????4 | ????0.14 | ????0.25 | ????0.58 | ????0.026 | ?0.015 |
Cooling parameter is compared with the prior art table to table 2 embodiment of the invention rolling technological parameter with rolling afterwards
| Lot number | Billet heating temperature (℃) | The start rolling temperature scope (℃) | In roll temperature range (℃) | Final final rolling temperature scope (℃) | Cooling rate after rolling (〉=℃/S) | Wear after rolling temperature range behind the water (℃) | In roll temperature control accumulative total deflection (%) |
| 1 | 950 | ??950 | ??800 | ??840 | ????10 | ????600 | ????54 |
| 2 | 950 | ??950 | ??830 | ??850 | ????10 | ????550 | ????58 |
| 3 | 950 | ??920 | ??850 | ??830 | ????10 | ????500 | ????63 |
| 4 | 1100 | ??950～1000 | ??820-780 | ????20 | ????530 |
The tensile property and the crystallite dimension of table 3 embodiment low-carbon screw thread reinforcing bar are compared with the prior art table
| Lot number | Ferrite grain size μ m | ????σ s????MPa | ????σ b????MPa | ????δ 5????％ | ????σ b/ ????σ s |
| ????1 | ????10 | ????460 | ????630 | ????22.5 | ????1.36 |
| ????2 | ????8 | ????450 | ????610 | ????25 | ????1.35 |
| ????3 | ????7.5 | ????520 | ????660 | ????22 | ????1.26 |
| ????4 | ????6.0 | ????430 | ????505 | ????36 | ????1.17 |
Claims (3)
1, a kind of milling method of low carbon steel twisted steel, it is characterized in that adopting the chemical composition (weight %) of reinforcing bar to be: C 0.17-0.23%, Si 0.20-0.80%, Mn 0.50-1.50%, S≤0.035%, P≤0.035%, this milling method comprise the steps: whole process or part of generating units temperature control are taked in steel rolling production, wherein:
(1) roughing section: low temperature open rolling, temperature are 850 ℃-950 ℃, utilize austenite dynamic recrystallization mechanism refine austenite crystal grain;
(2) section of rolling in: the control temperature utilizes the rolling and deformation induced ferritic phase variable mechanism of austenite non-recrystallization to obtain tiny ferrite crystal grain at 750 ℃-850 ℃;
(3) finish rolling section: temperature control utilizes ferrite dynamic recrystallization mechanism refinement ferrite crystal grain at 750 ℃-900 ℃;
Wear water control temperature＜600 ℃ after the finish to gauge, and it wears water cooling speed＞10 ℃/s.
2, the milling method of low carbon steel twisted steel according to claim 1, the section of rolling accumulative total distortion＞50% in the desired control temperature in it is characterized in that.
3, the milling method of low carbon steel twisted steel according to claim 1 is characterized in that above-mentioned process is applicable to the production of micro alloyed steel and low-alloy steel high tensile reinforcement.
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|---|---|---|---|
| CN 200410070096 CN1586750A (en) | 2004-08-20 | 2004-08-20 | Rolling method for low carbon twisted steel bar |
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|---|---|---|---|
| CN 200410070096 CN1586750A (en) | 2004-08-20 | 2004-08-20 | Rolling method for low carbon twisted steel bar |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100406602C (en) * | 2004-10-12 | 2008-07-30 | 昆明钢铁股份有限公司 | Dedicated base material for cold rolling reinforced steel-bar with ribs in low alloy |
| CN100412219C (en) * | 2006-02-11 | 2008-08-20 | 湖南华菱涟源钢铁有限公司 | Production method of III-grade threaded steel bar |
| CN101367094B (en) * | 2008-08-22 | 2011-02-02 | 马鞍山钢铁股份有限公司 | Combined control rolling process for hot-rolled steel bar with rib |
| CN102443687A (en) * | 2011-11-16 | 2012-05-09 | 钢铁研究总院 | Microstructure component controlling method for raising yield ratio of fine grain reinforced bar |
| CN102586563A (en) * | 2012-02-16 | 2012-07-18 | 马钢(集团)控股有限公司 | Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling |
| CN103556080A (en) * | 2013-10-24 | 2014-02-05 | 钢铁研究总院 | Mechanical property control method for directly rolling long profiles |
| CN109321833A (en) * | 2018-11-19 | 2019-02-12 | 河钢股份有限公司承德分公司 | A kind of hot rolling 400MPa grades of anchor pole reinforcing bars and its production method |
| CN110863094A (en) * | 2019-10-14 | 2020-03-06 | 盐城市联鑫钢铁有限公司 | Production process for solving bainite generation of niobium-containing deformed steel bar |
| CN111187980A (en) * | 2020-02-12 | 2020-05-22 | 钢铁研究总院 | Rare earth microalloyed high-strength construction steel bar and production method thereof |
| WO2021047295A1 (en) * | 2019-09-10 | 2021-03-18 | 南京钢铁股份有限公司 | Method for producing multi-stage structural steel blank for one steel |
| CN113388781A (en) * | 2021-05-28 | 2021-09-14 | 广西柳钢华创科技研发有限公司 | Method for producing HRB600E threaded steel bar by high-speed bar and HRB600E threaded steel bar produced by high-speed bar |
| CN114635026A (en) * | 2022-02-17 | 2022-06-17 | 包头钢铁（集团）有限责任公司 | Method for hot rolling ribbed steel bar to refine crystal grains |
| CN115976420A (en) * | 2022-12-23 | 2023-04-18 | 东北大学 | Low-cost 400 MPa-level spiral steel bar and preparation method thereof |
| CN116657052A (en) * | 2023-05-26 | 2023-08-29 | 本钢板材股份有限公司 | Low-cost steel for deformed bar and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100406602C (en) * | 2004-10-12 | 2008-07-30 | 昆明钢铁股份有限公司 | Dedicated base material for cold rolling reinforced steel-bar with ribs in low alloy |
| CN100412219C (en) * | 2006-02-11 | 2008-08-20 | 湖南华菱涟源钢铁有限公司 | Production method of III-grade threaded steel bar |
| CN101367094B (en) * | 2008-08-22 | 2011-02-02 | 马鞍山钢铁股份有限公司 | Combined control rolling process for hot-rolled steel bar with rib |
| CN102443687A (en) * | 2011-11-16 | 2012-05-09 | 钢铁研究总院 | Microstructure component controlling method for raising yield ratio of fine grain reinforced bar |
| CN102586563A (en) * | 2012-02-16 | 2012-07-18 | 马钢(集团)控股有限公司 | Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling |
| CN102586563B (en) * | 2012-02-16 | 2014-12-17 | 马钢(集团)控股有限公司 | Method for producing hot rolled ribbed bars by controlling austenite strain accumulation after finished rolling |
| CN103556080A (en) * | 2013-10-24 | 2014-02-05 | 钢铁研究总院 | Mechanical property control method for directly rolling long profiles |
| CN103556080B (en) * | 2013-10-24 | 2016-01-20 | 钢铁研究总院 | The property control method of Direct Rolling long profiles |
| CN109321833A (en) * | 2018-11-19 | 2019-02-12 | 河钢股份有限公司承德分公司 | A kind of hot rolling 400MPa grades of anchor pole reinforcing bars and its production method |
| WO2021047295A1 (en) * | 2019-09-10 | 2021-03-18 | 南京钢铁股份有限公司 | Method for producing multi-stage structural steel blank for one steel |
| CN110863094A (en) * | 2019-10-14 | 2020-03-06 | 盐城市联鑫钢铁有限公司 | Production process for solving bainite generation of niobium-containing deformed steel bar |
| CN111187980A (en) * | 2020-02-12 | 2020-05-22 | 钢铁研究总院 | Rare earth microalloyed high-strength construction steel bar and production method thereof |
| CN111187980B (en) * | 2020-02-12 | 2021-03-09 | 钢铁研究总院 | Rare earth microalloyed high-strength construction steel bar and production method thereof |
| CN113388781A (en) * | 2021-05-28 | 2021-09-14 | 广西柳钢华创科技研发有限公司 | Method for producing HRB600E threaded steel bar by high-speed bar and HRB600E threaded steel bar produced by high-speed bar |
| CN113388781B (en) * | 2021-05-28 | 2022-03-04 | 广西柳钢华创科技研发有限公司 | Method for producing HRB600E threaded steel bar by high-speed bar and HRB600E threaded steel bar produced by high-speed bar |
| CN114635026A (en) * | 2022-02-17 | 2022-06-17 | 包头钢铁（集团）有限责任公司 | Method for hot rolling ribbed steel bar to refine crystal grains |
| CN115976420A (en) * | 2022-12-23 | 2023-04-18 | 东北大学 | Low-cost 400 MPa-level spiral steel bar and preparation method thereof |
| CN115976420B (en) * | 2022-12-23 | 2024-08-06 | 东北大学 | Low-cost 400 MPa-level deformed bar and preparation method thereof |
| CN116657052A (en) * | 2023-05-26 | 2023-08-29 | 本钢板材股份有限公司 | Low-cost steel for deformed bar and preparation method thereof |
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