CN110863094A - Production process for solving bainite generation of niobium-containing deformed steel bar - Google Patents
Production process for solving bainite generation of niobium-containing deformed steel bar Download PDFInfo
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- CN110863094A CN110863094A CN201910970773.5A CN201910970773A CN110863094A CN 110863094 A CN110863094 A CN 110863094A CN 201910970773 A CN201910970773 A CN 201910970773A CN 110863094 A CN110863094 A CN 110863094A
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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
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
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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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to the technical field of metallurgy, in particular to a production process for solving the problem of bainite generation of niobium-containing deformed steel, which comprises the following operations: controlling the carbon content to be 0.21-0.25% and the niobium content to be 0.015-0.025%; controlling the manganese content of the molten steel to be lower than 1.35-1.45%; controlling the initial rolling temperature to be 900 ℃ and 950 ℃; the temperature of the finishing mill is ensured to be 850-900 ℃ by automatic temperature control and rolling in the middle; controlling the temperature of an upper cooling bed to 830-850 ℃; the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated. According to the controlled rolling and controlled cooling rolling process provided by the invention, proper molten steel components are controlled in steel making, and the stability of super-cooled austenite is weakened; the cooling speed and the temperature of an upper cooling bed are controlled in the steel rolling process, so that bainite is prevented from being formed; and the double-phase region rolling generates sub-crystal boundary ferrite, so that the yield strength of the deformed steel bar is improved, and the national III deformed steel bar standard performance requirements are met.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a production process for solving the problem of bainite generation of niobium-containing deformed steel.
Background
In order to ensure the yield strength and the processability of the building material deformed steel bar, the national relevant standards stipulate that the metallographic structure of the normal deformed steel bar is ferrite + pearlite, and other abnormal structures (such as bainite, martensite and the like) cannot appear. Bainite structures are detected in internal structures of HRB400 threads formed by microalloying niobium developed by a plurality of domestic steel mills, so that the yield of the deformed steel is not obvious, the toughness and the plasticity are poor, and the national standard requirements cannot be met. Most of niobium-containing deformed steel bars developed by a plurality of domestic steel mills improve the strength of the deformed steel bars by improving the niobium content, performing strong cooling after rolling and utilizing the solid solution strengthening and the fine grain strengthening of niobium. The process method has the following defects:
1. the solid solution strengthening has high niobium content which is generally controlled to be 0.03-0.04 percent, the stability of super-cooled austenite is improved, and a bainite structure is easy to generate;
2. after rolling, strong cooling is carried out, although the growth of austenite after rolling is inhibited, bainite tissues are easy to generate because the cooling speed is close to or reaches the critical transformation speed of bainite;
disclosure of Invention
The invention aims to solve the technical problem of providing a production process for solving the problem of bainite generation of niobium-containing deformed steel, which has low cost, poor stability of super-cooled austenite and difficult bainite generation.
The invention is realized by the following technical scheme:
a production process for solving the problem of bainite generation of niobium-containing deformed steel bars comprises the following operations:
controlling the carbon content to be 0.21-0.25%;
controlling the content of niobium to be 0.015-0.025%;
controlling the manganese content of the molten steel to be lower than 1.35-1.45%;
controlling the initial rolling temperature to be 900 ℃ and 950 ℃;
the temperature of the finishing mill is ensured to be 850-900 ℃ by automatic temperature control and rolling in the middle;
controlling the temperature of an upper cooling bed to 830-850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the first concrete embodiment, a production process for solving the problem of bainite generation of the niobium-containing deformed steel bar,
controlling the carbon content to be 0.21%;
controlling the content of niobium to be 0.015 percent;
controlling the manganese content of the molten steel to be lower than 1.35 percent;
controlling the initial rolling temperature to be 900 ℃;
the temperature of the finishing mill is ensured to be 850 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 830 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the second embodiment, a production process for solving the problem of bainite generation of the deformed steel containing niobium,
controlling the carbon content to be 0.25%;
controlling the content of niobium to be 0.025 percent;
controlling the manganese content of the molten steel to be lower than 1.45 percent;
controlling the initial rolling temperature to 950 ℃;
the temperature of the finishing mill is ensured to be 900 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the third embodiment, a production process for solving the problem of bainite generation of the deformed steel containing niobium,
controlling the carbon content to be 0.23%;
controlling the content of niobium to be 0.02 percent;
controlling the manganese content of the molten steel to be lower than 1.4 percent;
controlling the initial rolling temperature to be 900 ℃;
ensuring the temperature of the finishing mill to be 875 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of the upper cooling bed to be 840 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
Advantageous effects of the invention
According to the production process for solving the problem that the niobium-containing deformed steel bar generates bainite, the contents of niobium and manganese are low, and a bainite structure cannot be generated; and the ultra-fine grain structure is generated by adopting low-temperature rolling, the yield strength is improved, the deformed steel bar has stable performance and high elongation.
Detailed Description
A production process for solving the problem of bainite generation of niobium-containing deformed steel bars comprises the following operations:
controlling the carbon content to be 0.21-0.25%;
controlling the content of niobium to be 0.015-0.025%;
controlling the manganese content of the molten steel to be lower than 1.35-1.45%; controlling the content of niobium and manganese in the molten steel, and directly adding corresponding alloy elements by weight into the molten steel.
Controlling the initial rolling temperature to be 900 ℃ and 950 ℃;
the temperature of the finishing mill is ensured to be 850-900 ℃ by automatic temperature control and rolling in the middle;
controlling the temperature of an upper cooling bed to 830-850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the first concrete embodiment, a production process for solving the problem of bainite generation of the niobium-containing deformed steel bar,
controlling the carbon content to be 0.21%;
controlling the content of niobium to be 0.015 percent;
controlling the manganese content of the molten steel to be lower than 1.35 percent;
controlling the initial rolling temperature to be 900 ℃;
the temperature of the finishing mill is ensured to be 850 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 830 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the second embodiment, a production process for solving the problem of bainite generation of the deformed steel containing niobium,
controlling the carbon content to be 0.25%;
controlling the content of niobium to be 0.025 percent;
controlling the manganese content of the molten steel to be lower than 1.45 percent;
controlling the initial rolling temperature to 950 ℃;
the temperature of the finishing mill is ensured to be 900 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
In the third embodiment, a production process for solving the problem of bainite generation of the deformed steel containing niobium,
controlling the carbon content to be 0.23%;
controlling the content of niobium to be 0.02 percent;
controlling the manganese content of the molten steel to be lower than 1.4 percent;
controlling the initial rolling temperature to be 900 ℃;
ensuring the temperature of the finishing mill to be 875 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of the upper cooling bed to be 840 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
Due to the control process provided by the invention, the carbon content is controlled to be 0.21-0.25%, the niobium content is controlled to be 0.015-0.025%, the Mn content is controlled to be 1.35-1.45%, the stability of the super-cooled austenite is poor, and bainite is not easy to generate; the process is low-temperature rolling, and a large amount of ferrite subgrains are generated and grains are refined through low-temperature large deformation, deformation induced phase change and dual-phase region rolling instead of forced cold strengthening after rolling, so that the yield strength is improved, the deformed steel bar is stable in performance and high in elongation. The inspection data are detailed in table one.
Watch 1
As can be seen from the table above, the yield strength and tensile strength of the steel produced by the control process meet the standard requirements.
In conclusion, the production process for solving the problem that the niobium-containing deformed steel bar generates bainite is protected by the invention, and the supercooled austenite has poor stability and is not easy to generate bainite; the process is low-temperature rolling, and a large amount of ferrite subgrains are generated and grains are refined through low-temperature large deformation, deformation induced phase change and dual-phase area rolling.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A production process for solving the problem of bainite generation of niobium-containing deformed steel bars is characterized by comprising the following operations:
controlling the carbon content to be 0.21-0.25%;
controlling the content of niobium to be 0.015-0.025%;
controlling the manganese content of the molten steel to be lower than 1.35-1.45%;
controlling the initial rolling temperature to be 900 ℃ and 950 ℃;
the temperature of the finishing mill is ensured to be 850-900 ℃ by automatic temperature control and rolling in the middle;
controlling the temperature of an upper cooling bed to 830-850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
2. The production process for solving the problem of generating bainite in the niobium-containing deformed steel bar according to claim 1,
controlling the carbon content to be 0.21%;
controlling the content of niobium to be 0.015 percent;
controlling the manganese content of the molten steel to be lower than 1.35 percent;
controlling the initial rolling temperature to be 900 ℃;
the temperature of the finishing mill is ensured to be 850 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 830 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
3. The production process for solving the problem of generating bainite in the niobium-containing deformed steel bar according to claim 1,
controlling the carbon content to be 0.25%;
controlling the content of niobium to be 0.025 percent;
controlling the manganese content of the molten steel to be lower than 1.45 percent;
controlling the initial rolling temperature to 950 ℃;
the temperature of the finishing mill is ensured to be 900 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of an upper cooling bed to be 850 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
4. The production process for solving the problem of generating bainite in the niobium-containing deformed steel bar according to claim 1,
controlling the carbon content to be 0.23%;
controlling the content of niobium to be 0.02 percent;
controlling the manganese content of the molten steel to be lower than 1.4 percent;
controlling the initial rolling temperature to be 900 ℃;
ensuring the temperature of the finishing mill to be 875 ℃ through automatic temperature control and rolling control in the middle;
controlling the temperature of the upper cooling bed to be 840 ℃;
the low-temperature finish rolling reduction is 30%, and a sub-grain ferrite structure is generated.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910970773.5A CN110863094A (en) | 2019-10-14 | 2019-10-14 | Production process for solving bainite generation of niobium-containing deformed steel bar |
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| CN201910970773.5A CN110863094A (en) | 2019-10-14 | 2019-10-14 | Production process for solving bainite generation of niobium-containing deformed steel bar |
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| CN110863094A true CN110863094A (en) | 2020-03-06 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1586750A (en) * | 2004-08-20 | 2005-03-02 | 钢铁研究总院 | Rolling method for low carbon twisted steel bar |
| CN101367093A (en) * | 2008-08-22 | 2009-02-18 | 马鞍山钢铁股份有限公司 | Cooling controlling and rolling controlling process for hot-rolled steel bar with rib |
| CN103334058A (en) * | 2013-07-03 | 2013-10-02 | 南京钢铁股份有限公司 | Production process of deformed steel bar wire rod for high-speed rail |
| CN104018075A (en) * | 2014-06-25 | 2014-09-03 | 武汉钢铁(集团)公司 | Hot rolled ribbed steel bar with yield-to-tensile ratio of less than or equal to 0.8 and Rel of more than or equal to 600MPa, and production method |
| CN110295326A (en) * | 2019-08-07 | 2019-10-01 | 无锡东大汉森冶金实业有限公司 | The titanium micro-alloyed high-strength anti-seismic steel bar of HRB500E niobium and production technology |
-
2019
- 2019-10-14 CN CN201910970773.5A patent/CN110863094A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1586750A (en) * | 2004-08-20 | 2005-03-02 | 钢铁研究总院 | Rolling method for low carbon twisted steel bar |
| CN101367093A (en) * | 2008-08-22 | 2009-02-18 | 马鞍山钢铁股份有限公司 | Cooling controlling and rolling controlling process for hot-rolled steel bar with rib |
| CN103334058A (en) * | 2013-07-03 | 2013-10-02 | 南京钢铁股份有限公司 | Production process of deformed steel bar wire rod for high-speed rail |
| CN104018075A (en) * | 2014-06-25 | 2014-09-03 | 武汉钢铁(集团)公司 | Hot rolled ribbed steel bar with yield-to-tensile ratio of less than or equal to 0.8 and Rel of more than or equal to 600MPa, and production method |
| CN110295326A (en) * | 2019-08-07 | 2019-10-01 | 无锡东大汉森冶金实业有限公司 | The titanium micro-alloyed high-strength anti-seismic steel bar of HRB500E niobium and production technology |
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