CN104404380A - High strength steel bar for pre-stressed concrete and production technology thereof - Google Patents
High strength steel bar for pre-stressed concrete and production technology thereof Download PDFInfo
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- CN104404380A CN104404380A CN201410621536.5A CN201410621536A CN104404380A CN 104404380 A CN104404380 A CN 104404380A CN 201410621536 A CN201410621536 A CN 201410621536A CN 104404380 A CN104404380 A CN 104404380A
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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
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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
- 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
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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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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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
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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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
- C22C38/18—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
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
Abstract
The invention discloses a high strength steel bar for pre-stressed concrete. The steel bar is composed of the following chemical components in percentage by weight: 0.20 to 0.25% of C, 1.50 to 1.85% of Si, 0.20 to 0.50% of Mn, 0.07 to 0.09% of Cr, 0.30 to 0.35% of Mo, 0.25 to 0.35% of V, 0.05 to 0.08% of Nb, 0.42 to 0.61% of Ti, 0.15 to 0.25% of Ni, 0.25 to 0.40% of Ca, not more than 0.025% of S, not more than 0.025% of P, not more than 0.20% of Cu, 0.15 to 0.30% of composite rare earth, and the balance being Fe. The invention further discloses a production technology of the steel bar. The production technology comprises the following steps: smelting to obtain a steel blank, rolling the steel blank, cooling the rolled steel blank, rolling the steel blank for a second time, carrying out a thermal treatment and a stabilizing treatment, performing a gas nitrogenation treatment, spinning, winding, bundling, and storing the bundles in a warehouse.
Description
Technical field
The invention belongs to technical field of smelting, relate to a kind of rod iron and production technique thereof, specifically a kind of high-strength steel bar for prestressed concrete and production technique thereof.
Background technology
The prestressing steel of China is produced and is started in the initial stage the 60's of 20th century; because affecting by planned economy; just start exploitation to latter stage the 80's of 20th century and introduce this technology; because the automation degree of equipment of domestic production is at that time relatively low, operation is discontinuous, the production efficiency of the prestressed steel bar product that the initial stage is developed is very low, cost is higher, be difficult to formation large-scale production.Along with deepening continuously of China's economic construction and reform and opening-up, " eight or five " period, domestic Ji Jia enterprise and scientific research institutions' joint development have gone out the higher continuous prestressed steel bar production line of a kind of level of automation, but are difficult to produce a desired effect due to the Harmony of Controlling System and the shortcoming of design.The enforcement period of the ninth five-year plan, the quality standard of China to Constructional Steel has had certain understanding, progressively introduces prestressing steel production line.Tangshan Iron and Steel Co has introduced domestic Article 1 PC rod iron production line in 1994, between a few years, domestic Shuo Jia enterprise is successively from having introduced 10 prestressed steel bar production lines abroad, add more than 20 bar domestic production lines after trimming, annual production reaches more than 20 ten thousand tons.The fast development of China's high-speed wire mill, facilitates the design of prestressed concrete structure engineering, construction and the technology upgrading of materials and update.But define the serious situation that supply exceed demand, the selling price of prestress steel section product is gone way down, Recovery of payment cycle stretch-out, make many enterprises be in the situation of half stopping production or stopping production.Since 1999, due to the quickening of southern region following the line of the sea economic construction paces, building trade fast development, make prestressing steel brisk in the market, former half production line stopping production or stop production is restarted, and updating along with the PC rod iron quality of production, and its people are to the deep understanding of a series of benefits that structural steel high performance-price ratio is brought, its application is more and more general, and output is also in steady-state growth.The file regulation that Department of Construction of Guangdong Province put into effect in 2000, builds building pile tube used and must use PC rod iron.According to statistics, current Chinese PC rod iron throughput has reached more than 1,000,000 tons.
The production technique of general steel bar for prestressed concrete is unwrapping wire-rust cleaning of peeling off-sizing cutting-alignment-induction heating-quenching-tempering-cooling-transmission-shearing separated time-take-up at present, process costs is high, waste steel, complex procedures operates inconvenience and the shortcomings such as produced rod iron poor performance, ductility are poor, easy fracture, these rod irons are applied on engineering, buildings, the susceptibility of its delayed fracture presents linear increase, risk is large, and this will cause immeasurable hidden danger of quality and huge financial loss to steel bar for prestressed concrete industry.
Summary of the invention
Technical problem to be solved by this invention is, for the shortcoming that above prior art exists, a kind of high-strength steel bar for prestressed concrete and production technique thereof are proposed, this rod iron intensity is high, good-extensibility, the advantages such as anti-delayed fracture resistance by force, easily welds, upsetting performance is good, its production technique is simple to operation simultaneously, administration measure efficiency is high, saves steel saving cost.
The technical scheme that the present invention solves above technical problem is:
A kind of high-strength steel bar for prestressed concrete, its weight percent chemical composition is: C:0.20-0.25%, Si:1.50-1.85%, Mn:0.20-0.50%, Cr:0.07-0.09%, Mo:0.30-0.35%, V:0.25-0.35%, Nb:0.05-0.08%, Ti:0.42-0.61%, Ni:0.15-0.25%, Ca:0.25-0.40%, S≤0.025%, P≤0.025%, Cu≤0.20%, compound rare-earth: 0.15-0.30%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 5-8%, gadolinium: 8-10%, yttrium: 8-10%, cerium: 15-20%, praseodymium: 23-25%, neodymium: 12-15%, dysprosium: 11-14%, and all the other are lanthanum, and above each component sum is 100%.
The technical scheme that the present invention limits further is:
In aforementioned high-strength steel bar for prestressed concrete, its weight percent chemical composition is: C:0.25%, Si:1.65%, Mn:0.20%, Cr:0.08%, Mo:0.35%, V:0.25%, Nb:0.08%, Ti:0.50%, Ni:0.25%, Ca:0.30%, S:0.025%, P:0.010%, Cu:0.15%, compound rare-earth: 0.20%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 5%, gadolinium: 8%, yttrium: 9%, cerium: 20%, praseodymium: 23%, neodymium: 12%, dysprosium: 14%, and all the other are lanthanum, and above each component sum is 100%.
In aforementioned high-strength steel bar for prestressed concrete, its weight percent chemical composition is: C:0.20%, Si:1.50%, Mn:0.50%, Cr:0.07%, Mo:0.30%, V:0.35%, Nb:0.05%, Ti:0.42%, Ni:0.15%, Ca:0.25%, S:0.015%, P:0.015%, Cu:0.20%, compound rare-earth: 0.15%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 8%, gadolinium: 9%, yttrium: 8%, cerium: 18%, praseodymium: 25%, neodymium: 15%, dysprosium: 11%, and all the other are lanthanum, and above each component sum is 100%.
In aforementioned high-strength steel bar for prestressed concrete, its weight percent chemical composition is: C:0.22%, Si:1.85%, Mn:0.35%, Cr:0.09%, Mo:0.33%, V:0.30%, Nb:0.07%, Ti:0.61%, Ni:0.18%, Ca:0.40%, S:0.020%, P:0.025%, Cu:0.15%, compound rare-earth: 0.30%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 7%, gadolinium: 10%, yttrium: 10%, cerium: 15%, praseodymium: 24%, neodymium: 13%, dysprosium: 13%, and all the other are lanthanum, and above each component sum is 100%.
The present invention have also been devised a kind of production technique of high-strength steel bar for prestressed concrete, and concrete production technique is as follows:
(1) said components is obtained steel billet as raw material after converter smelting, refining treatment, continuous casting, then steel billet is heated to 1000-1500 DEG C by walking beam furnace, steel billet after heating is come out of the stove and is carried out high-pressure water descaling, de-scaling pressure setting is 15-18MPa, and after de-scaling, steel billet temperature is 900-990 DEG C;
(2) steel billet after de-scaling in step (1) is sent into mill milling, steel billet enters stove preheating section temperature and controls at 660-710 DEG C, and Heating temperature is 850-920 DEG C, heating 1.5-3h, roughing temperature is 1000-1180 DEG C, and roughing completes temperature and controls more than 950, and finishing temperature is 800-850 DEG C;
(3) cooling down treatment process is carried out to control its inside metallographic to the steel billet after rolling in step (2);
Cooling down treatment process is specially: adopt water-cooled to be combined with air cooling, first adopt water-cooled, with the rate of cooling of 3.5-4.0 DEG C/s, steel billet water is chilled to 500-550 DEG C, then air cooling is to 350-450 DEG C, adopt water-cooled, with the rate of cooling of 3.0-3.5 DEG C/s, steel billet water is chilled to 150-185 DEG C again, last air cooling is to room temperature;
(4) steel billet being cooled to room temperature is sent into milling train again and carry out second time rolling, roughing temperature controls at 1000-1100 DEG C, and final rolling temperature controls at 950-980 DEG C, weakly after rolling is chilled to 750-820 DEG C, then naturally cools to room temperature;
(5) heat-treated and be cooled to room temperature by the steel billet in step (4) after twice rolling, carrying out stabilization treatment be heated to 800-850 DEG C to cooled steel billet, insulation 10-15min, carries out air cooling subsequently or stove is chilled to room temperature;
(6) gas nitriding process is carried out to the billet surface after stabilized process in step (5) and finally obtain rod iron, steel billet to be positioned in gas nitriding furnace and to pass into NH in stove
3, stove is warming up to 500-525 DEG C, keeps 10-15h;
(7) rod iron through gas nitriding process is sent into Laying head, weaving silk at laying temperature is 750-790 DEG C, it is cold to form coil shape line space of going forward side by side, after air cooling, break into drum further through collector;
(8) rod iron breaking into drum is sent into bander carry out bundling and weigh, finally enter stockyard.
The technical scheme that the present invention limits further is:
In the production technique of high-strength steel bar for prestressed concrete, step is heat-treated steel billet in (5), and concrete operation step is as follows:
A anneals: by steel billet stove heat to 780-820 DEG C and blowing out after being incubated 1-2h, stove is cooled to 420-450 DEG C, opens fire door subsequently and continues slow cooling to 190-250 DEG C of air cooling of coming out of the stove to room temperature;
B quenches: steel billet slow stove heat after annealing in step a is incubated 7-9h to 890-910 DEG C, then directly uses Water spray steel billet fast cooling;
C tempering: by through quenching after steel billet at room temperature again enter stove and stove heat to 390-405 DEG C after be incubated 7-8h after come out of the stove cold lack, on cooling bed, air cooling is carried out to steel billet, first with the speed of cooling of 4-6 per second DEG C, steel billet is cooled to 200-280 DEG C, and then progressively cools to room temperature.
In the production technique of high-strength steel bar for prestressed concrete, be also included in step (8) and the rod iron feeding bander breaking into drum is carried out bundling and weighs, before finally entering stockyard, drum rod iron is checked one by one, reject defective rod iron
The invention has the beneficial effects as follows:
The component that the present invention have adjusted high-strength steel bar for prestressed concrete changes structural state to strengthen original austenite crystal prevention, to stop the suction of hydrogen, and reduce Hydrogen diffusion coefficient etc., thus improve the ability of the anti-Delayed hydride cracking of rod iron, concrete measure is as follows:
(1) segregation of P, S Inclusions Along original austenite crystal prevention is reduced; (2) reduce Mn, Si content, suppress the grain boundary segregation of P; (3) in order to improve tempering temperature, the content of Si is brought up to more than 1.5%; (4) still can reach required intensity in order to ensure during tempering, add the alloy carbides such as Mo, V and separate out element; (5) Nb, V, Ti micro alloying element is added with crystal grain thinning; (6) add Ni and make its richness gather in steel surface by rolling and heat treatment process, to reduce soakage and the spread coefficient of hydrogen.
The Si in Ca composition compound composition is also added in the component of high-strength steel bar for prestressed concrete of the present invention, rupture time can be increased, this is because Ca has the effect controlling inclusion, impel MnS to the transformation of spherical CaS, reduce the deleterious effect of MnS, enhance the bonding strength of original austenite crystal prevention, thus the anti-delayed fracture performance of rod iron is improved.
Also add Cr, Nb, V, Ni in the component of high-strength steel bar for prestressed concrete of the present invention thus can improve the atom active of C and N element, the air mass that each atom is formed can form strong interaction with dislocation, pinning dislocation, produces yield point elongation; Wherein: Cr, increase the hardening capacity of steel, significantly improve intensity, hardness and wear resistance, too increase solidity to corrosion and the resistance of oxidation of steel; Ni, improves the intensity of steel, and keeps good plasticity and toughness.Nickel has higher corrosion resistance to soda acid, at high temperature has antirust and temperature capacity; Nb, the superheated susceptivity of crystal grain thinning and reduction steel and temper brittleness, improve intensity, also can prevent intergranular corrosion phenomenon.
The steel billet being cooled to room temperature is sent into milling train and is carried out second time rolling by present invention process step (4) again, and roughing temperature controls at 1000-1100 DEG C, and final rolling temperature controls at 950-980 DEG C, weakly after rolling is chilled to 750-820 DEG C, then naturally cools to room temperature; In conjunction with weak cold mode, twice rolling effectively ensures that the grain fineness number of the rod iron after rolling reaches more than 9 grades, rod iron rapid heating after rolling stops growing up of autstenitic grain size, keep close grain state, after ensure that subsequent heat treatment, the grain fineness number of rod iron reaches more than 11 grades, keeps super-high-plasticity while grain refining process can improve rapidly yield strength and tensile strength.
Water-cooled is adopted to be combined with air cooling when carrying out cooling process to steel billet in the step (3) of present invention process, be followed successively by: water-cooled-air cooling-water-cooled-air cooling, like this, controlled by the cooling after tempering, carbide can be made fully to dissolve, even diffusion, avoiding carbide causes intergranular corrosion and spot corrosion to exceed standard in the precipitation of intergranular, ensure that the ferrite content of material is less than 0.5%, material solid solution can also be made abundant, avoid heat treatment mode heating uneven, the erosion rate that solid solution inequality is brought exceeds standard and hardness exceeds standard, thus bring pulling of another technical indicator, obtain beyond thought technique effect.
The present invention checks one by one product after rod iron is made, guarantee conforming product rate, the advantages such as steel bar for prestressed concrete intensity of the present invention is high, ductility good, anti-delayed fracture resistance is strong, easily welding, upsetting performance are good, simultaneously its production technique simple to operation, save steel saving cost.
Embodiment
embodiment 1
The present embodiment provides a kind of high-strength steel bar for prestressed concrete, and its weight percent chemical composition is: C:0.25%, Si:1.65%, Mn:0.20%, Cr:0.08%, Mo:0.35%, V:0.25%, Nb:0.08%, Ti:0.50%, Ni:0.25%, Ca:0.30%, S:0.025%, P:0.010%, Cu:0.15%, compound rare-earth: 0.20%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 5%, gadolinium: 8%, yttrium: 9%, cerium: 20%, praseodymium: 23%, neodymium: 12%, dysprosium: 14%, and all the other are lanthanum, and above each component sum is 100%.
The production technique of above-mentioned high-strength steel bar for prestressed concrete, concrete production technique is as follows:
(1) said components is obtained steel billet as raw material after converter smelting, refining treatment, continuous casting, then steel billet is heated to 1000 DEG C by walking beam furnace, steel billet after heating is come out of the stove and is carried out high-pressure water descaling, and de-scaling pressure setting is 18MPa, and after de-scaling, steel billet temperature is 900 DEG C;
(2) steel billet after de-scaling in step (1) is sent into mill milling, steel billet enters stove preheating section temperature and controls at 700 DEG C, and Heating temperature is 850 DEG C, heating 2h, and roughing temperature is 1180 DEG C, and roughing completes temperature and controls more than 950, and finishing temperature is 850 DEG C;
(3) cooling down treatment process is carried out to control its inside metallographic to the steel billet after rolling in step (2);
Cooling down treatment process is specially: adopt water-cooled to be combined with air cooling, first adopt water-cooled, with the rate of cooling of 4.0 DEG C/s, steel billet water is chilled to 550 DEG C, then air cooling to 350 DEG C, then adopt water-cooled, with the rate of cooling of 3.2 DEG C/s, steel billet water is chilled to 150 DEG C, last air cooling is to room temperature;
(4) steel billet being cooled to room temperature is sent into milling train again and carry out second time rolling, roughing temperature controls at 1025 DEG C, and final rolling temperature controls at 950 DEG C, weakly after rolling is chilled to 800 DEG C, then naturally cools to room temperature;
(5) heat-treated and be cooled to room temperature by the steel billet in step (4) after twice rolling, carrying out stabilization treatment be heated to 850 DEG C to cooled steel billet, insulation 15min, carries out air cooling subsequently or stove is chilled to room temperature;
Thermal treatment, concrete operation step is as follows:
A anneals: by steel billet stove heat to 820 DEG C and blowing out after being incubated 1.5h, stove is cooled to 420-450 DEG C, opens fire door subsequently and continues slow cooling to 190-250 DEG C of air cooling of coming out of the stove to room temperature;
B quenches: steel billet slow stove heat after annealing in step a is incubated 7-9h to 890-910 DEG C, then directly uses Water spray steel billet fast cooling;
C tempering: by through quenching after steel billet at room temperature again enter stove and stove heat to 390-405 DEG C after be incubated 7-8h after come out of the stove cold lack, on cooling bed, air cooling is carried out to steel billet, first with the speed of cooling of 4-6 per second DEG C, steel billet is cooled to 200-280 DEG C, and then progressively cools to room temperature;
(6) gas nitriding process is carried out to the billet surface after stabilized process in step (5) and finally obtain rod iron, steel billet to be positioned in gas nitriding furnace and to pass into NH in stove
3, stove is warming up to 500 DEG C, keeps 13h;
(7) rod iron through gas nitriding process is sent into Laying head, weaving silk at laying temperature is 750 DEG C, it is cold to form coil shape line space of going forward side by side, after air cooling, break into drum further through collector;
(8) drum rod iron is checked one by one, reject defective rod iron, the rod iron breaking into drum is sent into bander and carries out bundling and weigh, finally enter stockyard.
embodiment 2
The present embodiment provides a kind of high-strength steel bar for prestressed concrete, and its weight percent chemical composition is: C:0.20%, Si:1.50%, Mn:0.50%, Cr:0.07%, Mo:0.30%, V:0.35%, Nb:0.05%, Ti:0.42%, Ni:0.15%, Ca:0.25%, S:0.015%, P:0.015%, Cu:0.20%, compound rare-earth: 0.15%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 8%, gadolinium: 9%, yttrium: 8%, cerium: 18%, praseodymium: 25%, neodymium: 15%, dysprosium: 11%, and all the other are lanthanum, and above each component sum is 100%.
The production technique of above-mentioned high-strength steel bar for prestressed concrete, concrete production technique is as follows:
(1) said components is obtained steel billet as raw material after converter smelting, refining treatment, continuous casting, then steel billet is heated to 1250 DEG C by walking beam furnace, steel billet after heating is come out of the stove and is carried out high-pressure water descaling, and de-scaling pressure setting is 17MPa, and after de-scaling, steel billet temperature is 990 DEG C;
(2) steel billet after de-scaling in step (1) is sent into mill milling, steel billet enters stove preheating section temperature and controls at 710 DEG C, and Heating temperature is 900 DEG C, heating 3h, and roughing temperature is 1050 DEG C, and roughing completes temperature and controls more than 950, and finishing temperature is 800 DEG C;
(3) cooling down treatment process is carried out to control its inside metallographic to the steel billet after rolling in step (2);
Cooling down treatment process is specially: adopt water-cooled to be combined with air cooling, first adopt water-cooled, with the rate of cooling of 3.5 DEG C/s, steel billet water is chilled to 500 DEG C, then air cooling to 450 DEG C, then adopt water-cooled, with the rate of cooling of 3.0 DEG C/s, steel billet water is chilled to 185 DEG C, last air cooling is to room temperature;
(4) steel billet being cooled to room temperature is sent into milling train again and carry out second time rolling, roughing temperature controls at 1100 DEG C, and final rolling temperature controls at 980 DEG C, weakly after rolling is chilled to 750 DEG C, then naturally cools to room temperature;
(5) heat-treated and be cooled to room temperature by the steel billet in step (4) after twice rolling, carrying out stabilization treatment be heated to 800 DEG C to cooled steel billet, insulation 10min, carries out air cooling subsequently or stove is chilled to room temperature;
Thermal treatment, concrete operation step is as follows:
A anneals: by steel billet stove heat to 780 DEG C and blowing out after being incubated 2h, stove is cooled to 420 DEG C, opens fire door subsequently and continues slow cooling to 250 DEG C and come out of the stove air cooling to room temperature;
B quenches: steel billet slow stove heat after annealing in step a is incubated 9h to 910 DEG C, then directly uses Water spray steel billet fast cooling;
C tempering: by through quenching after steel billet at room temperature again enter stove and stove heat to 405 DEG C after be incubated 7h after come out of the stove cold lack, on cooling bed, air cooling is carried out to steel billet, first with the speed of cooling of 6 DEG C per second, steel billet is cooled to 280 DEG C, and then progressively cools to room temperature;
(6) gas nitriding process is carried out to the billet surface after stabilized process in step (5) and finally obtain rod iron, steel billet to be positioned in gas nitriding furnace and to pass into NH in stove
3, stove is warming up to 525 DEG C, keeps 15h;
(7) rod iron through gas nitriding process is sent into Laying head, weaving silk at laying temperature is 790 DEG C, it is cold to form coil shape line space of going forward side by side, after air cooling, break into drum further through collector;
(8) drum rod iron is checked one by one, reject defective rod iron, the rod iron breaking into drum is sent into bander and carries out bundling and weigh, finally enter stockyard.
embodiment 3
The present embodiment provides a kind of high-strength steel bar for prestressed concrete, and its weight percent chemical composition is: C:0.22%, Si:1.85%, Mn:0.35%, Cr:0.09%, Mo:0.33%, V:0.30%, Nb:0.07%, Ti:0.61%, Ni:0.18%, Ca:0.40%, S:0.020%, P:0.025%, Cu:0.15%, compound rare-earth: 0.30%, surplus is Fe;
The component of compound rare-earth is by mass percentage: holmium: 7%, gadolinium: 10%, yttrium: 10%, cerium: 15%, praseodymium: 24%, neodymium: 13%, dysprosium: 13%, and all the other are lanthanum, and above each component sum is 100%.
The production technique of above-mentioned high-strength steel bar for prestressed concrete, concrete production technique is as follows:
(1) said components is obtained steel billet as raw material after converter smelting, refining treatment, continuous casting, then steel billet is heated to 1500 DEG C by walking beam furnace, steel billet after heating is come out of the stove and is carried out high-pressure water descaling, and de-scaling pressure setting is 15MPa, and after de-scaling, steel billet temperature is 950 DEG C;
(2) steel billet after de-scaling in step (1) is sent into mill milling, steel billet enters stove preheating section temperature and controls at 660 DEG C, and Heating temperature is 920 DEG C, heating 1.5h, and roughing temperature is 1000 DEG C, and roughing completes temperature and controls more than 950, and finishing temperature is 825 DEG C;
(3) cooling down treatment process is carried out to control its inside metallographic to the steel billet after rolling in step (2);
Cooling down treatment process is specially: adopt water-cooled to be combined with air cooling, first adopt water-cooled, with the rate of cooling of 3.8 DEG C/s, steel billet water is chilled to 525 DEG C, then air cooling to 380 DEG C, then adopt water-cooled, with the rate of cooling of 3.5 DEG C/s, steel billet water is chilled to 175 DEG C, last air cooling is to room temperature;
(4) steel billet being cooled to room temperature is sent into milling train again and carry out second time rolling, roughing temperature controls at 1000 DEG C, and final rolling temperature controls at 970 DEG C, weakly after rolling is chilled to 820 DEG C, then naturally cools to room temperature;
(5) heat-treated and be cooled to room temperature by the steel billet in step (4) after twice rolling, carrying out stabilization treatment be heated to 820 DEG C to cooled steel billet, insulation 13min, carries out air cooling subsequently or stove is chilled to room temperature;
Thermal treatment, concrete operation step is as follows:
A anneals: by steel billet stove heat to 800 DEG C and blowing out after being incubated 1h, stove is cooled to 450 DEG C, opens fire door subsequently and continues slow cooling to 200 DEG C and come out of the stove air cooling to room temperature;
B quenches: steel billet slow stove heat after annealing in step a is incubated 7h to 890 DEG C, then directly uses Water spray steel billet fast cooling;
C tempering: by through quenching after steel billet at room temperature again enter stove and stove heat to 390 DEG C after be incubated 7.5h after come out of the stove cold lack, on cooling bed, air cooling is carried out to steel billet, first with the speed of cooling of 4 DEG C per second, steel billet is cooled to 250 DEG C, and then progressively cools to room temperature;
(6) gas nitriding process is carried out to the billet surface after stabilized process in step (5) and finally obtain rod iron, steel billet to be positioned in gas nitriding furnace and to pass into NH in stove
3, stove is warming up to 545 DEG C, keeps 10h;
(7) rod iron through gas nitriding process is sent into Laying head, weaving silk at laying temperature is 760 DEG C, it is cold to form coil shape line space of going forward side by side, after air cooling, break into drum further through collector;
(8) drum rod iron is checked one by one, reject defective rod iron, the rod iron breaking into drum is sent into bander and carries out bundling and weigh, finally enter stockyard.
In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of application claims.
Claims (7)
1. a high-strength steel bar for prestressed concrete, is characterized in that, its weight percent chemical composition is: C:0.20-0.25%, Si:1.50-1.85%, Mn:0.20-0.50%, Cr:0.07-0.09%, Mo:0.30-0.35%, V:0.25-0.35%, Nb:0.05-0.08%, Ti:0.42-0.61%, Ni:0.15-0.25%, Ca:0.25-0.40%, S≤0.025%, P≤0.025%, Cu≤0.20%, compound rare-earth: 0.15-0.30%, surplus is Fe;
The component of described compound rare-earth is by mass percentage: holmium: 5-8%, gadolinium: 8-10%, yttrium: 8-10%, cerium: 15-20%, praseodymium: 23-25%, neodymium: 12-15%, dysprosium: 11-14%, and all the other are lanthanum, and above each component sum is 100%.
2. high-strength steel bar for prestressed concrete according to claim 1, is characterized in that, its weight percent chemical composition is: C:0.25%, Si:1.65%, Mn:0.20%, Cr:0.08%, Mo:0.35%, V:0.25%, Nb:0.08%, Ti:0.50%, Ni:0.25%, Ca:0.30%, S:0.025%, P:0.010%, Cu:0.15%, compound rare-earth: 0.20%, surplus is Fe;
The component of described compound rare-earth is by mass percentage: holmium: 5%, gadolinium: 8%, yttrium: 9%, cerium: 20%, praseodymium: 23%, neodymium: 12%, dysprosium: 14%, and all the other are lanthanum, and above each component sum is 100%.
3. high-strength steel bar for prestressed concrete according to claim 1, is characterized in that, its weight percent chemical composition is: C:0.20%, Si:1.50%, Mn:0.50%, Cr:0.07%, Mo:0.30%, V:0.35%, Nb:0.05%, Ti:0.42%, Ni:0.15%, Ca:0.25%, S:0.015%, P:0.015%, Cu:0.20%, compound rare-earth: 0.15%, surplus is Fe;
The component of described compound rare-earth is by mass percentage: holmium: 8%, gadolinium: 9%, yttrium: 8%, cerium: 18%, praseodymium: 25%, neodymium: 15%, dysprosium: 11%, and all the other are lanthanum, and above each component sum is 100%.
4. high-strength steel bar for prestressed concrete according to claim 1, is characterized in that, its weight percent chemical composition is: C:0.22%, Si:1.85%, Mn:0.35%, Cr:0.09%, Mo:0.33%, V:0.30%, Nb:0.07%, Ti:0.61%, Ni:0.18%, Ca:0.40%, S:0.020%, P:0.025%, Cu:0.15%, compound rare-earth: 0.30%, surplus is Fe;
The component of described compound rare-earth is by mass percentage: holmium: 7%, gadolinium: 10%, yttrium: 10%, cerium: 15%, praseodymium: 24%, neodymium: 13%, dysprosium: 13%, and all the other are lanthanum, and above each component sum is 100%.
5. the production technique of high-strength steel bar for prestressed concrete according to claim arbitrary in claim 1-4, it is characterized in that, concrete production technique is as follows:
(1) said components is obtained steel billet as raw material after converter smelting, refining treatment, continuous casting, then steel billet is heated to 1000-1500 DEG C by walking beam furnace, steel billet after heating is come out of the stove and is carried out high-pressure water descaling, de-scaling pressure setting is 15-18MPa, and after de-scaling, steel billet temperature is 900-990 DEG C;
(2) steel billet after de-scaling in step (1) is sent into mill milling, steel billet enters stove preheating section temperature and controls at 660-710 DEG C, and Heating temperature is 850-920 DEG C, heating 1.5-3h, roughing temperature is 1000-1180 DEG C, and roughing completes temperature and controls more than 950, and finishing temperature is 800-850 DEG C;
(3) cooling down treatment process is carried out to control its inside metallographic to the steel billet after rolling in step (2);
Described cooling down treatment process is specially: adopt water-cooled to be combined with air cooling, first adopt water-cooled, with the rate of cooling of 3.5-4.0 DEG C/s, steel billet water is chilled to 500-550 DEG C, then air cooling is to 350-450 DEG C, adopt water-cooled, with the rate of cooling of 3.0-3.5 DEG C/s, steel billet water is chilled to 150-185 DEG C again, last air cooling is to room temperature;
(4) steel billet being cooled to room temperature is sent into milling train again and carry out second time rolling, roughing temperature controls at 1000-1100 DEG C, and final rolling temperature controls at 950-980 DEG C, weakly after rolling is chilled to 750-820 DEG C, then naturally cools to room temperature;
(5) heat-treated and be cooled to room temperature by the steel billet in step (4) after twice rolling, carrying out stabilization treatment be heated to 800-850 DEG C to cooled steel billet, insulation 10-15min, carries out air cooling subsequently or stove is chilled to room temperature;
(6) gas nitriding process is carried out to the billet surface after stabilized process in step (5) and finally obtain rod iron, steel billet to be positioned in gas nitriding furnace and to pass into NH in stove
3, stove is warming up to 500-525 DEG C, keeps 10-15h;
(7) rod iron through gas nitriding process is sent into Laying head, weaving silk at laying temperature is 750-790 DEG C, it is cold to form coil shape line space of going forward side by side, after air cooling, break into drum further through collector;
(8) rod iron breaking into drum is sent into bander carry out bundling and weigh, finally enter stockyard.
6. the production technique of high-strength steel bar for prestressed concrete according to claim 1, is characterized in that: described step is heat-treated steel billet in (5), and concrete operation step is as follows:
A anneals: by steel billet stove heat to 780-820 DEG C and blowing out after being incubated 1-2h, stove is cooled to 420-450 DEG C, opens fire door subsequently and continues slow cooling to 190-250 DEG C of air cooling of coming out of the stove to room temperature;
B quenches: steel billet slow stove heat after annealing in step a is incubated 7-9h to 890-910 DEG C, then directly uses Water spray steel billet fast cooling;
C tempering: by through quenching after steel billet at room temperature again enter stove and stove heat to 390-405 DEG C after be incubated 7-8h after come out of the stove cold lack, on cooling bed, air cooling is carried out to steel billet, first with the speed of cooling of 4-6 per second DEG C, steel billet is cooled to 200-280 DEG C, and then progressively cools to room temperature.
7. the production technique of high-strength steel bar for prestressed concrete according to claim 1, it is characterized in that: be also included in step (8) and the rod iron feeding bander breaking into drum is carried out bundling and weighs, before finally entering stockyard, drum rod iron is checked one by one, reject defective rod iron.
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| CN201410621536.5A CN104404380B (en) | 2014-11-07 | A kind of high-strength steel bar for prestressed concrete and production technology thereof |
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| CN104404380A true CN104404380A (en) | 2015-03-11 |
| CN104404380B CN104404380B (en) | 2017-01-04 |
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| CN103741022A (en) * | 2013-11-27 | 2014-04-23 | 内蒙古包钢钢联股份有限公司 | High strength building steel bar |
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| CN104882832B (en) * | 2015-05-29 | 2019-03-19 | 金海新源电气江苏有限公司 | A kind of vertical male bend of ladder-type leads to gantry and preparation method thereof |
| CN105908098A (en) * | 2016-04-29 | 2016-08-31 | 江苏金源腾峰换热设备有限公司 | Treatment process for low-temperature corrosion resisting condenser tube |
| CN108048750A (en) * | 2017-12-15 | 2018-05-18 | 苏州赛斯德工程设备有限公司 | A kind of corrosion-resistant tensile type steel alloy and its production technology |
| CN109372869A (en) * | 2018-09-30 | 2019-02-22 | 江苏永昊高强度螺栓有限公司 | A kind of high-strength bolt and its manufacturing method |
| CN111041363A (en) * | 2019-12-13 | 2020-04-21 | 首钢集团有限公司 | 1420 Mpa-grade prestressed steel material and preparation method and application thereof |
| CN113637925A (en) * | 2020-04-27 | 2021-11-12 | 宝山钢铁股份有限公司 | Steel for quenched and tempered continuous oil pipe, hot-rolled steel strip, steel pipe and manufacturing method thereof |
| CN111961986A (en) * | 2020-08-26 | 2020-11-20 | 盐城市联鑫钢铁有限公司 | High-strength corrosion-resistant steel bar and manufacturing method thereof |
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