CN109097682B - High-strength refractory steel bar and preparation method thereof - Google Patents
High-strength refractory steel bar and preparation method thereof Download PDFInfo
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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
- C22C38/04—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
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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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
- C21D2211/002—Bainite
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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
- C21D2211/005—Ferrite
Abstract
The invention discloses a high-strength fire-resistant reinforcing steel bar and a preparation method thereof, wherein the high-strength fire-resistant reinforcing steel bar comprises the following components in percentage by weight: c is more than or equal to 0.15 and less than or equal to 0.22 percent; si is more than or equal to 0.35 and less than or equal to 0.50 percent; mn is more than or equal to 1.3 and less than or equal to 1.6 percent; p is less than or equal to 0.015 percent; s is less than or equal to 0.01 percent; ni is more than or equal to 0.50 and less than or equal to 0.65 percent; v is more than or equal to 0.02% and less than or equal to 0.08%; nb is more than or equal to 0.04 and less than or equal to 0.10; cr is between 0.5 and 0.8 percent; mo is more than or equal to 0.15 percent and less than or equal to 0.35 percent, and the balance is Fe and inevitable impurities. The preparation method comprises the steps of adding alloy elements of the refractory steel bar into molten iron for smelting and casting blanks, sequentially carrying out rough rolling and finish rolling, and carrying out air cooling and air cooling after finish rolling to obtain the high-strength refractory steel bar with a microstructure of ferrite + bainite structure and M/A island. The preparation method has the advantages of simple process, easy operation and control and higher production efficiency.
Description
Technical Field
The invention relates to the technical field of reinforcing steel bars for buildings, in particular to a high-strength fire-resistant reinforcing steel bar and a preparation method thereof.
Background
At present, the construction industry develops rapidly, and the performance and the quality of the steel for the construction, especially the steel bar for the construction, become one of important links for judging whether the construction is safe and reliable or not and whether the design life of the construction can be ensured or not in the construction industry. Especially, the occurrence of fire in high-rise buildings poses a serious threat and loss to the life safety and property of people. The importance of the fire resistance of construction steel reinforcement to building safety is gradually recognized.
The prior patent literature discloses the components and process of "a refractory steel bar and its production process" (CN 104032234A). In the patent, an electromagnetic stirring process is required during molten steel smelting, the production process is complex, and through water cooling is adopted in the rolling process. The water cooling is not adopted by the national standard in the treatment method after the rolling of the hot rolled steel bar.
The prior patent literature also discloses a 600MPa high-performance fire-resistant anti-seismic reinforcing steel bar for concrete and preparation thereof (CN 102796961A). In the process of rolling the steel billet, the controlled rolling and controlled cooling process is adopted, but the process is more complex.
Therefore, the provided refractory steel bar with high strength, high temperature resistance and simple production process has very important and profound significance in the research field of constructional steel.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a high-temperature-resistant and high-strength fire-resistant reinforcing steel bar and a preparation method of the fire-resistant reinforcing steel bar with a simple process.
One of the technical schemes of the invention is to provide a high-strength fire-resistant reinforcing steel bar which is characterized by comprising the following components in percentage by weight: c is more than or equal to 0.15 percent and less than or equal to 0.22 percent, Si is more than or equal to 0.50 percent and less than or equal to 0.50 percent, Mn is more than or equal to 1.6 percent and less than or equal to 1.3 percent, P is more than or equal to 0.015 percent, S is more than or equal to 0.01 percent, Ni is more than or equal to 0.50 percent and less than or equal to 0.65 percent, V is more than or equal to 0.02 percent and less than or equal to 0.08 percent, Nb is more than or equal to 0.04 percent and less than or equal to 0.10 percent, Cr is more than or equal to 0.5 percent. Re with the weight percentage of more than or equal to 0.005 percent and less than or equal to 0.01 percent is also added into the refractory reinforcing steel bar so as to improve the integral high-temperature resistance of the reinforcing steel bar.
The invention also provides a preparation method of the high-strength fire-resistant reinforcing steel bar, which comprises the following steps:
sintering iron ore to obtain sintered ore, and smelting the sintered ore in a blast furnace to obtain molten iron;
b, adding alloy elements consisting of the components of the refractory steel bar into molten iron for smelting, controlling the percentage of the components of the molten iron in the smelting, and controlling the content of each element;
c, casting the smelted molten steel, heating the casting blank to 750-850 ℃ at a heating rate of 4.0-8.0 ℃/s, then heating to 1100-1200 ℃ at a heating rate of 8.0-12.0 ℃/s, controlling the temperature to 1060-1100 ℃, and preserving heat for 25-35 min;
d, carrying out rough rolling and finish rolling on the steel billet obtained after casting, wherein the rough rolling initial rolling temperature is controlled to be 1010-; controlling the initial rolling temperature of finish rolling to be 965-1005 ℃, the rolling pass of finish rolling to be 7-12, the total reduction rate to be 40-50%, the cumulative reduction rate of the last three passes to be 10-20%, and the final rolling temperature to be 900-940 ℃;
e, performing air cooling and air cooling on the steel bars after finish rolling, wherein the cooling rate is 20-30 ℃/s, and the steel bars are cooled to room temperature when the temperature is between 680 ℃ and 700 ℃;
f, finishing, packaging and inspecting.
The microstructure of the high-strength refractory steel bar prepared by the invention is a ferrite and bainite structure and an M/A island. The yield strength of the refractory steel bar can reach more than 450 MPa.
According to the invention, by adding various elements in the components of the steel bar, particularly adding the components of Cr, Mo and Ni and reasonably adjusting the contents of the components, the high-temperature resistance of the steel bar is more obvious, and the good effects of fire resistance and high temperature resistance are realized. Meanwhile, the preparation method for producing the high-strength refractory steel bar has the advantages of simple process, easiness in control and operation and further improvement of production efficiency.
Detailed Description
The design ideas and the specific embodiments of the present invention are explained in detail below with reference to exemplary embodiments. The present invention may be variously modified and may include various embodiments. Shown below are preferred embodiments.
The design idea of the invention is that the produced steel bar has high temperature resistance and high strength through the synergistic effect of a plurality of alloy elements. The use of the building is safer and more reliable in the building. The invention adds the contents of alloy elements such as vanadium, chromium, molybdenum, nickel and the like into steel, thereby not only improving the strength of the steel bar, but also improving the fire resistance of the steel bar. The preparation method adopts the air cooling process after rolling, so that the driving force of solid solution strengthening and precipitation separation is increased, the steel bar with the microstructure of ferrite and bainite structures and an M/A island is obtained, the high temperature resistance of the steel is improved, and the strength is obviously improved. The invention also adjusts and adds the component contents of Cr, Mo and Ni, so that the steel bar has the characteristic of high temperature resistance, and the effects of fire resistance and high temperature resistance can be realized. And a more reasonable and proper amount of Ni is added, so that the strength of the steel is improved strongly, and the Ni has good thermal fatigue resistance. The invention also adds Re element with Re content of more than or equal to 0.005% and less than or equal to 0.01% into the components of the refractory steel bar. And the proper amount of Re is added into the steel, so that the molten steel can be purified, the integral high-temperature resistance of the steel is obviously improved, the high-temperature strength is kept, and the overheating sensitivity of the steel can be reduced.
The technical scheme of the invention comprises two parts, and one technical scheme is to provide a high-strength fire-resistant reinforcing steel bar. The refractory steel bar comprises the following components in percentage by weight: c is more than or equal to 0.15 percent and less than or equal to 0.22 percent, Si is more than or equal to 0.50 percent and less than or equal to 0.50 percent, Mn is more than or equal to 1.6 percent and less than or equal to 1.3 percent, P is more than or equal to 0.015 percent, S is more than or equal to 0.01 percent, Ni is more than or equal to 0.50 percent and less than or equal to 0.65 percent, V is more than or equal to 0.02 percent and less than or equal to 0.08 percent, Nb is more than or equal to 0.04 percent and less than or equal to 0.10 percent, Cr is more than or equal to 0.5 percent. Re with the weight percentage of more than or equal to 0.005 percent and less than or equal to 0.01 percent can also be added into the refractory steel bar so as to improve the integral high-temperature resistance of the steel bar. The other technical scheme is to provide a preparation method of the high-strength fire-resistant reinforcing steel bar. The method comprises the following implementation steps: adopting iron ore sintered ore, smelting in a blast furnace to obtain molten iron, adding alloy elements consisting of components of refractory steel bars into the molten iron for smelting, controlling the percentage of the components of the molten iron in the smelting and the content of each element, and continuously casting the smelted molten steel into a casting blank; then heating the casting blank to 750-850 ℃ at a heating rate of 4.0-8.0 ℃/s, then heating to 1100-1200 ℃ at a heating rate of 8.0-12.0 ℃/s, controlling the temperature to be 1060-1100 ℃, and preserving heat for 25-35 min; carrying out rough rolling and finish rolling on a steel billet obtained after casting, wherein the rough rolling starting temperature is controlled to be 1010-; carrying out finish rolling after rough rolling, controlling the finish rolling start temperature to be 965 and 1005 ℃, controlling the finish rolling pass to be 7-12, and controlling the total rolling reduction rate to be 40-50%; wherein, the accumulated reduction rate of the last three times is controlled to be 10-20%, and the final rolling temperature is 900-; and (3) carrying out air cooling and air cooling on the finish-rolled steel bar, wherein the cooling rate is 20-30 ℃/s, the steel bar temperature is air-cooled to 680-700 ℃, and the air cooling is carried out to room temperature, and finally, finishing, packaging and inspecting are carried out. The final inspection result shows that the microstructure of the high-strength refractory steel bar prepared by the invention is ferrite + bainite structure and M/A island. The yield strength of the refractory steel bar can reach more than 450 MPa. The invention achieves the aim of fire resistance and high temperature resistance.
Example 1
Firstly, sintering iron ore to obtain sinter, and smelting the sinter in a blast furnace to obtain molten iron. The method comprises the following steps of charging molten iron with the total volume of 5 tons into a 10-ton converter, adding alloy composition elements such as manganese, silicon, niobium, vanadium, chromium, molybdenum and the like into the molten iron, and controlling the percentage of each element in the molten iron within the following range: c: 0.19%, Si 0.45%, Mn 1.45%, P0.012%, S: 0.01%, Ni: 0.55 percent of the alloy, 0.05 percent of V, 0.07 percent of Nb, 0.7 percent of Cr, 0.25 percent of Mo, and the balance of Fe and other inevitable impurities.
The molten iron is desulfurized, and converter smelting adopts a double-slag method for dephosphorization, so that the content of sulfur and phosphorus in the molten iron meets the requirement. And blowing argon from the top and the bottom of the converter to refine and carry out vacuum treatment on the molten iron to obtain molten steel so as to further control the content of each element in the molten steel.
And casting the molten steel into a casting blank, specifically a continuous casting blank, feeding the steel blank into a heating furnace, heating to 750-850 ℃ at a heating rate of 4.0-8.0 ℃/s, then heating to 1100-1200 ℃ at a heating rate of 8.0-12.0 ℃/s, controlling the temperature to be 1060-1100 ℃, and preserving heat for 25-35 min.
Specifically, in the embodiment, the steel billet is fed into a heating furnace to be heated to 800 ℃ at the speed of 6.0 ℃/s, then heated to 1150 ℃ at the speed of 10 ℃/s, and then the temperature is controlled to 1080 ℃, and the temperature is kept for 25min, and during the specific operation, the adaptive adjustment can be made according to the actual production situation.
And carrying out rough rolling on the steel billet, wherein the initial rolling temperature of the rough rolling is controlled to be between 1010 and 1050 ℃, the number of rough rolling passes is 3-5, the total rolling reduction rate is 50-60%, the temperature of the obtained plate blank after the rough rolling is finished is the final rolling temperature, and the temperature range of the final rolling is controlled to be 970 and 1010 ℃. In this example, the rough rolling temperature of the billet was controlled at 1050 ℃, 4 passes of rough rolling were performed, the total reduction was 60%, and the final rolling temperature was 1000 ℃.
And (3) performing finish rolling on the roughly rolled plate blank, wherein the finish rolling start temperature is controlled to be 965-1005 ℃, the rolling pass is 7-12, and the total reduction rate is 40-50%. Wherein, the cumulative reduction rate of the last three times is controlled to be 10-20%. And the temperature of the steel bar obtained after the finish rolling is the finish rolling temperature, and the finish rolling temperature is controlled to be between 900 ℃ and 940 ℃. In this example, the initial rolling temperature of the finish rolling was controlled to 980 ℃, and the finish rolling was performed for 8 passes with a total reduction of 45% and a finishing temperature of 920 ℃.
And (3) carrying out air cooling and air cooling on the steel bars obtained by finish rolling in sequence, wherein the cooling rate of the air cooling is 20-30 ℃/s until the temperature of the steel bars is 680-700 ℃, and then carrying out air cooling to the room temperature. In this embodiment, the cooling rate of the air-cooling of the finish-rolled steel bar is 29 ℃/s, and the steel bar is air-cooled to room temperature when the temperature of the steel bar is air-cooled to 680 ℃. Then finishing, packaging and inspecting.
Example 2
And smelting sintered ore in a blast furnace to obtain molten iron. In this example, in addition to the elements added in example 1, Re was added to the molten iron, and the percentage of each element in the molten iron was controlled to be within the following range: c: 0.155%, Si: 0.35%, Mn: 1.6%, P: 0.010%, S: 0.008%, Ni: 0.65%, V: 0.03%, Nb: 0.04%, Cr: 0.5%, Mo: 0.35%, Re: 0.006%, and the balance Fe and other unavoidable impurities.
Proper amount of Re element in 0.006% is added into steel bar to purify molten steel. After casting and rolling, the high-temperature strength of the steel bar is obviously improved, the overheating sensitivity of steel is reduced, and the overall high-temperature resistance and corrosion resistance of the steel bar are improved.
In the smelting process, molten iron is desulfurized, converter smelting and double-slag dephosphorization are adopted, so that the content of sulfur and phosphorus in the molten iron meets the technical requirements. And blowing argon from the top and the bottom of the converter to refine and carry out vacuum treatment on the molten iron to obtain molten steel, and further controlling the content of each element in the molten steel.
In the embodiment, the steel billet is sent into a heating furnace to be heated to 850 ℃ at the speed of 8.0 ℃/s, then heated to 1190 ℃ at the speed of 11 ℃/s, the temperature is controlled at 1100 ℃, and the temperature is kept for 30min, and the steel billet can be adaptively adjusted in a data range according to the actual production condition during specific operation.
In this example, the temperature of rough rolling of the steel slab was controlled to 1030 ℃, 5 passes of rough rolling were performed, the total reduction was 55%, and the final rolling temperature was 1010 ℃.
The slab after the rough rolling was subjected to finish rolling, and in this example, the finish rolling temperature was controlled at 990 ℃, and 10 passes of finish rolling were performed, with a total reduction of 40%. The temperature of the second finish rolling is controlled at 940 ℃.
And air cooling are sequentially carried out on the steel bars obtained after finish rolling. In this embodiment, the cooling rate of the finish-rolled steel bar is 25 ℃/s, and the steel bar is air-cooled to room temperature when the temperature of the steel bar is 690 ℃. And then finishing and packaging are carried out, and the finished product is ready for use after inspection.
Example 3
Iron ore sinter is adopted to obtain molten iron through blast furnace smelting. In this example, in addition to the elements added in example 1, Re was added to the molten iron, and the percentage of each element in the molten iron was controlled to be within the following range: c: 0.22%, Si: 0.50%, Mn: 1.35%, P: 0.015%, S: 0.009%, Ni: 0.60%, V: 0.08%, Nb: 0.10%, Cr: 0.8%, Mo: 0: 15%, Re: 0.009%, and the balance of Fe and other inevitable impurities.
Desulfurizing molten iron, dephosphorizing by converter smelting, and controlling the contents of sulfur and phosphorus in the molten iron; and refining the molten iron in a converter and carrying out vacuum treatment to obtain molten steel, and further controlling the content of each element in the molten steel to enable the molten steel to meet the required component content.
The molten steel is continuously cast to obtain a casting blank, the steel blank is sent into a heating furnace to be heated to 750 ℃ at the speed of 5.0 ℃/s, then is heated to 1100 ℃ at the speed of 9 ℃/s, the temperature is controlled to 1070 ℃, the temperature is kept for 35min, and the adaptability adjustment can be made in a data range according to the actual production condition.
And (3) roughly rolling the steel billet, controlling the temperature of rough rolling of the steel billet to be 1020 ℃, and roughly rolling the steel billet for 5 times, wherein the total reduction rate is 55%, and the final rolling temperature is 1000 ℃. Performing finish rolling on the rough-rolled plate blank, wherein the finish rolling temperature is controlled to be 980 ℃ in the embodiment, performing finish rolling for 11 times, and the total rolling reduction rate is 45%; the finishing temperature is controlled at 930 ℃.
And air cooling are sequentially carried out on the steel bars obtained after finish rolling. In this embodiment, the cooling rate of the finish-rolled steel bar is 22 ℃/s, and the steel bar is air-cooled to the room temperature when the temperature of the steel bar is 700 ℃. And then finishing and packaging are carried out, and the finished product is ready for use after inspection.
In the embodiment of the invention, the ferrovanadium micro-alloy is added into the produced steel bar, and the rapid controlled cooling process after rolling is adopted, so that the driving force of solid solution strengthening and precipitation separation is increased, the steel bar with a microstructure of ferrite + bainite structure and M/A island is obtained, the high temperature resistance of the steel is improved, and the strength is obviously improved. The proper amount of Cr in the steel bar is adjusted to be 0.7%, so that a further passive film is promoted to be formed on the surface of the steel bar, and the steel bar and 0.25% of Mo have a composite effect, so that the fire resistance of the steel is easier to improve. Because the content of Mo is reasonably controlled, a certain precipitation strengthening effect is achieved in steel, and the high-temperature performance of the steel bar is correspondingly improved. By reasonably adding alloy elements and adjusting the content of the alloy elements, the proportion combination is more optimized. And then smelting, casting and combining with the steel rolling process are reasonably combined for use, so that the high-strength refractory steel bar has excellent refractory performance, good corrosion resistance and higher yield strength, and shows excellent comprehensive mechanical properties in the actual use of steel bar members.
Because the invention adopts reasonable component composition and optimized component content and adopts the simple and easy-to-operate preparation method, the invention can produce the high-strength fire-resistant reinforcing steel bar which completely meets the use requirement of buildings under the state of saving materials and production cost to the utmost extent.
Table 1 shows the mechanical properties of the fire resistant steel bars of examples 1-3 at room temperature and 600 ℃.
TABLE 1 EXAMPLES 1-3 mechanical Properties of fire-resistant reinforcing bars at Room temperature and 600 deg.C
As can be seen from the mechanical property data in specific examples 1-3 in Table 1, the tensile strength of the high-strength refractory steel bar prepared by the invention at room temperature reaches 600MPa or more, and the yield strength of the high-strength refractory steel bar is above 455MPa on average. The contrast value of the yield strength of the material at 600 ℃ and 20 ℃ reaches more than 0.580, and the material shows excellent fire resistance and high temperature resistance.
The above-described embodiments of the present invention are merely exemplary, and various changes may be made in these embodiments without departing from the design concept of the present invention, which will be defined in the appended claims and their equivalents.
Claims (3)
1. The high-strength fire-resistant steel bar is characterized by comprising the following components in percentage by weight: c is more than or equal to 0.15 percent and less than or equal to 0.22 percent, Si is more than or equal to 0.50 percent and less than or equal to 0.50 percent, Mn is more than or equal to 1.6 percent and less than or equal to 1.3 percent, P is more than or equal to 0.015 percent, S is more than or equal to 0.01 percent, Ni is more than or equal to 0.50 percent and less than or equal to 0.65 percent, V is more than or equal to 0.02 percent and less than or equal to 0.08 percent, Nb is more than or equal to 0.04 percent and less than or equal to 0.10 percent, Cr is more than or equal to 0.5 percent; the microstructure of the refractory steel bar is a ferrite and bainite structure and an M/A island;
the refractory steel bar further contains Re, wherein the Re comprises the following components in percentage by weight: re is more than or equal to 0.005 percent and less than or equal to 0.01 percent.
2. The high-strength fire-resistant reinforcing bar according to claim 1, wherein the method for preparing the fire-resistant reinforcing bar comprises the steps of:
sintering iron ore to obtain sintered ore, and smelting the sintered ore in a blast furnace to obtain molten iron;
b, adding alloy elements consisting of the components of the refractory steel bar into molten iron for smelting, controlling the percentage of the components of the molten iron in the smelting, and controlling the content of each element;
c, casting the smelted molten steel, heating the casting blank to 750-850 ℃ at a heating rate of 4.0-8.0 ℃/s, then heating to 1100-1200 ℃ at a heating rate of 8.0-12.0 ℃/s, controlling the temperature to 1060-1100 ℃, and preserving heat for 25-35 min;
d, carrying out rough rolling and finish rolling on the billet obtained after casting blank in sequence, controlling the initial rolling temperature of the rough rolling to be 1010-1050 ℃, the rolling pass of the rough rolling to be 3-5, the total rolling reduction rate to be 50-60% and the final rolling temperature of the rough rolling to be 970-1010 ℃; controlling the initial rolling temperature of finish rolling to be 965-1005 ℃, the rolling pass of finish rolling to be 7-12, the total rolling reduction rate to be 40-50%, the cumulative reduction rate of the last three passes to be 10-20%, and the final rolling temperature to be 900-940 ℃;
e, air cooling and air cooling the finish-rolled steel bars in sequence, wherein the cooling rate of the air cooling is 20-30 ℃/s, and the steel bars are cooled to 680-700 ℃ in air and then cooled to room temperature in time;
f, finishing, packaging and inspecting.
3. The high-strength refractory steel bar according to claim 2, wherein said smelting is performed in a converter or an electric furnace; the casting blank is a continuous casting blank.
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| CN110952037B (en) * | 2019-11-18 | 2021-05-28 | 阳春新钢铁有限责任公司 | 400MPa hot-rolled refractory steel bar and manufacturing method thereof |
| CN111575607A (en) * | 2020-06-29 | 2020-08-25 | 张家港联峰钢铁研究所有限公司 | Preparation method of refractory steel bar for reinforced concrete |
| CN113061805B (en) * | 2021-03-12 | 2022-05-03 | 盐城市联鑫钢铁有限公司 | 600 MPa-grade corrosion-resistant rare earth reinforcing steel bar and production method thereof |
| CN114672743B (en) * | 2022-03-02 | 2022-09-16 | 福建三宝钢铁有限公司 | Preparation method of low-alloy structural steel Q355 |
| CN115341154A (en) * | 2022-09-21 | 2022-11-15 | 南通瑞泰针业有限公司 | High-toughness and high-strength sewing machine needle |
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| CN1194113C (en) * | 2003-04-30 | 2005-03-23 | 清华大学 | Mn-Si-Cr air-cooled granular bainite/ferrite polyphase Steel |
| CN104032234B (en) * | 2014-05-23 | 2016-06-29 | 武汉钢铁(集团)公司 | A kind of fire-resistant reinforcing bar and production technology thereof |
| CN104178697B (en) * | 2014-08-26 | 2016-05-11 | 武汉钢铁(集团)公司 | A kind of high-temperature resistant anti-shock reinforcing bar and production method thereof |
| CN108103405B (en) * | 2017-12-29 | 2019-10-25 | 钢研晟华科技股份有限公司 | A kind of high-strength fireproof anti-seismic steel bar and its low cost preparation method |
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