CN112375967B - Hot-bending elbow steel strip with excellent strength and toughness and production method thereof - Google Patents
Hot-bending elbow steel strip with excellent strength and toughness and production 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- 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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- 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
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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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Abstract
The invention discloses a hot-bending elbow steel strip with excellent obdurability, which comprises the following chemical components in percentage by mass: 0.05 to 0.12 percent of C; 0.10 to 0.30 percent of Si; 1.30 to 1.70 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.005 percent; nb 0.025-0.050%; mo 0.10-0.18%; 0.010 to 0.040 percent of Ti; alt 0.020-0.050%; ni 0.10-0.20%; 0.10 to 0.20 percent of Cr and 0.0010 to 0.0030 percent of Ca; the balance of Fe and other residual elements of the raw materials. Its preparing process is also disclosed. The design of the invention adopts Nb + Ti + Mo + Cr + N alloy composition system design and 2250mm controlled rolling and cooling process, thus ensuring excellent comprehensive performance of the material; obtain proper proportion of tissue and ensure excellent matching of the toughness and the toughness of the material.
Description
Technical Field
The invention relates to the field of material research and development, in particular to a hot-bending elbow steel strip with excellent obdurability and a production method thereof.
Background
The obdurability of the hot-bending bend determines the safety of the pipeline steel engineering project, and the hot-bending bend is in service under complex and severe working condition environments for a long time. As an important connecting member, the high-strength and low-toughness steel should meet the application requirements.
At present, the bent pipe is researched and produced by domestic steel mills, and the following problems mainly exist: firstly, the obdurability indexes of the materials are not completely matched, and the use safety of downstream users cannot be met; secondly, the stress state of the bent pipes in different grades is complex in use, and the performance index after heat treatment is lower than the standard. The invention develops a hot-bending bend steel strip with strong toughness and excellent toughness and a production method thereof mainly by a steel cleaning smelting technology and a rolling and cooling control technology.
The retrieved patent discloses a hot-rolled flat plate for an X70 elbow with excellent toughness and a production method thereof, which mainly describes that the hot-rolled flat plate for the X70 elbow is produced by using a continuous casting billet through reasonable component design and rolling process, and the maximum thickness of the product is 32 mm; the invention adopts a low-cost alloy composition design, utilizes 2250mm to control a cooling control process, develops a hot-bending bend steel strip with high strength and toughness and a production method thereof, meets the use safety of downstream users, and has low manufacturing cost.
According to the X80 hot-rolled steel plate for the hot-bending mother pipe and the manufacturing method thereof, the X80 hot-rolled steel plate for the hot-bending mother pipe is produced by adding alloy components, and the raw material cost is high. But the invention selects and adds more Ti and Cr with low alloy cost and adds a small amount of noble metal elements Nb, Mo and Ni, thereby realizing low-cost stable production.
The patent of retrieval, namely a hot-rolled flat plate for an X65 hot-bending bend and a production method thereof, mainly describes that a clean steel smelting process is adopted, and the content of easily segregated elements such as C, P, S and the like and the lower superheat degree of molten steel are strictly controlled; through continuous casting and soft reduction technology, the center segregation low-power grade C reaches 0.5 grade; through the process technology, the steel plate is ensured to obtain fine and uniform tissue morphology and control the banded structure. But the invention combines the clean steel smelting technology and the controlled rolling and controlled cooling technology, and can ensure the obdurability index of the material and ensure the application safety.
Disclosure of Invention
The invention aims to design and develop a hot-bending bend steel strip with excellent obdurability and a production method thereof by adopting alloy components and a controlled rolling and controlled cooling process, the inclusion control, strength index and low-temperature toughness index of the finished steel strip are better, and the use of downstream users of the hot-rolled steel strip can be well ensured.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a hot-bending elbow steel strip with excellent obdurability, which comprises the following chemical components in percentage by mass: 0.05 to 0.12 percent of C; 0.10 to 0.30 percent of Si; 1.30 to 1.70 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.005 percent; nb 0.025-0.050%; mo 0.10-0.18%; 0.010 to 0.040 percent of Ti; alt 0.020-0.050%; ni 0.10-0.20%; 0.10 to 0.20 percent of Cr and 0.0010 to 0.0030 percent of Ca; the balance of Fe and other residual elements of the raw materials.
Further, the chemical components in percentage by mass are as follows: 0.07 percent of C; 0.20 percent of Si; 1.55 percent of Mn; p is 0.010 percent; 0.003 percent of S; 0.035% of Nb; 0.15 percent of Mo; 0.015 percent of Ti; alt 0.035%; 0.15 percent of Ni; 0.15% of Cr and 0.0020% of Ca; the balance of Fe and other residual elements of the raw materials.
A method for producing a hot-bending steel strip with excellent toughness comprises the following steps:
(1) clean steel smelting technology
A refining procedure: slagging and desulfurizing in an LF furnace, and adding alloys such as aluminum iron, ferromanganese, ferrosilicon, niobium, ferromolybdenum and the like to adjust the range of target components;
RH processing procedure: the vacuum degree is required to be less than or equal to 2.6mbar, and the vacuum maintaining time is more than or equal to 10 min; adding ferrotitanium alloy according to the components of molten steel during RH vacuum treatment to adjust the components; ensuring that the circulating pure degassing time is more than or equal to 7 min; after RH vacuum treatment is finished, calcium wires are fed for calcium treatment, and soft blowing time is guaranteed to be more than 10min after wire feeding;
and (3) continuous casting process: the liquidus temperature of the steel grade is 1518 ℃, the superheat degree of the molten steel of the first ladle is 25-40 ℃, and the superheat degree of the molten steel of other heats is 15-30 ℃; the casting machine adopts a constant drawing speed;
(2) controlled rolling and cooling technology
A hot rolling procedure: the heating temperature of the plate blank is controlled to be 1160-1175 ℃; the furnace time is controlled at 180-240 min; the rough rolling adopts a 3+3 mode or a 1+5 mode, the reduction of each pass is not lower than 10%, the reduction rate of the 5 th pass and the 6 th pass is not lower than 20%, and the uniformity and the fine structure characteristics of the material structure are ensured; the finish rolling initial rolling temperature is controlled to be less than or equal to 1000 ℃; the final rolling temperature is controlled to be 805-835 ℃; the coiling temperature is 460-500 ℃.
Further, a continuous casting billet is smelted on a 240-ton converter and produced on a 2250mm rolling mill.
Compared with the prior art, the invention has the beneficial technical effects that:
the design adopts Nb + Ti + Mo + Cr + N alloy component system design and 2250mm controlled rolling and cooling process, so that excellent comprehensive performance of the material is ensured; obtain proper proportion of tissue and ensure excellent matching of the toughness and the toughness of the material.
Drawings
The invention is further illustrated in the following description with reference to the drawings.
FIG. 1 is a microstructure of material # 1 and the microstructure of inclusions;
FIG. 2 is a microstructure of the No. 2 material and a microstructure of inclusions.
Detailed Description
The following are preferred embodiments of the present invention, and do not limit the scope of the present invention.
The invention develops a hot-bending elbow steel strip with excellent obdurability based on the production technology, which comprises the following chemical components in percentage by mass: 0.05 to 0.12 percent of C; 0.10 to 0.30 percent of Si; 1.30 to 1.70 percent of Mn; p is less than or equal to 0.015 percent; s is less than or equal to 0.005 percent; nb 0.025-0.050%; mo 0.10-0.18%; 0.010 to 0.040 percent of Ti; alt 0.020-0.050%; ni 0.10-0.20%; 0.10 to 0.20 percent of Cr0.10 percent, 0.0010 to 0.0030 percent of Ca; the balance of Fe and other residual elements of the raw materials.
Nb + Ti alloy elements are preferably added, and the mechanism of grain refinement and precipitation strengthening is further realized through the precipitated carbon and nitride composite precipitated particles; the added Mo element can be preferably used for refining the structure of a casting blank; the Cr element is preferably added to improve the hardenability of the steel strip; more preferably, Ni element is added, so that the austenite structure can be stabilized, and the low-temperature toughness of the material can be improved. The design of the Nb + Ti + Mo + Cr + Ni alloy composition system with a proper proportion is comprehensively determined, so that the toughness matching of the hot-bending elbow is ensured.
Furthermore, the method for producing the steel strip for the hot-bending elbow with excellent obdurability comprises the following steps:
according to the component design and the production method provided by the invention, a continuous casting billet is smelted on a 240-ton converter and produced on a 2250mm rolling mill, the chemical components of the continuous casting billet are shown in Table 1, the process parameters of a heating furnace are shown in Table 2, and the process parameters of the rolling mill are shown in Table 3.
Table 1 chemical composition units: is based on
TABLE 2 Process parameters of the furnace
TABLE 3 Rolling mill Process parameters
Examples 1 to 3
1. Tensile properties of the material
TABLE 4 tensile Properties
2. Low temperature toughness of materials
TABLE 5 series temperature shock test (full size)
TABLE 6 drop test
3. Texture and inclusions of material
TABLE 7 inclusions and banded structure rating
The microstructure is shown in FIGS. 1 and 2.
In conclusion, the safe hot-bending elbow steel strip with good internal quality control, moderate strength index margin in all directions, excellent Charpy V-type low-temperature impact toughness and stable drop hammer tearing performance is developed by adopting the Nb + Ti + Mo + Cr + Ni alloy component system design and the 2250mm controlled rolling and cooling process.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (2)
1. A hot-bending elbow steel strip with excellent obdurability is characterized in that: the chemical components by mass percentage are as follows: 0.07 percent of C; 0.20 percent of Si; 1.55 percent of Mn; p is 0.010 percent; 0.003 percent of S; 0.035% of Nb; 0.15 percent of Mo; 0.015 percent of Ti; alt 0.035%; 0.15 percent of Ni; 0.15% of Cr and 0.0020% of Ca; the balance of Fe and other residual elements of the raw materials;
the production method comprises the following steps:
(1) clean steel smelting technology
A refining procedure: slagging and desulfurizing in an LF furnace, and adding alloys such as aluminum iron, ferromanganese, ferrosilicon, niobium, ferromolybdenum and the like to adjust the range of target components;
RH processing procedure: the vacuum degree is required to be less than or equal to 2.6mbar, and the vacuum maintaining time is more than or equal to 10 min; adding ferrotitanium alloy according to the components of molten steel during RH vacuum treatment to adjust the components; ensuring that the circulating pure degassing time is more than or equal to 7 min; after RH vacuum treatment is finished, calcium wires are fed for calcium treatment, and soft blowing time is guaranteed to be more than 10min after wire feeding;
and (3) continuous casting process: the liquidus temperature of the steel grade is 1518 ℃, the superheat degree of the molten steel of the first ladle is 25-40 ℃, and the superheat degree of the molten steel of other heats is 15-30 ℃; the casting machine adopts a constant drawing speed;
(2) controlled rolling and cooling technology
A hot rolling procedure: the heating temperature of the plate blank is controlled to be 1160-1175 ℃; the furnace time is controlled at 180-240 min; the rough rolling adopts a 3+3 mode or a 1+5 mode, the reduction of each pass is not lower than 10%, the reduction rate of the 5 th pass and the 6 th pass is not lower than 20%, and the uniformity and the fine structure characteristics of the material structure are ensured; the finish rolling initial rolling temperature is controlled to be less than or equal to 1000 ℃; the final rolling temperature is controlled to be 805-835 ℃; the coiling temperature is 460-500 ℃.
2. The hot-bend steel strip excellent in toughness according to claim 1, characterized in that: the continuous casting billet is smelted on a 240-ton converter and produced on a 2250mm rolling mill.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011123398.XA CN112375967B (en) | 2020-10-20 | 2020-10-20 | Hot-bending elbow steel strip with excellent strength and toughness and production method thereof |
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| CN202011123398.XA CN112375967B (en) | 2020-10-20 | 2020-10-20 | Hot-bending elbow steel strip with excellent strength and toughness and production method thereof |
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| CN112375967B true CN112375967B (en) | 2022-04-19 |
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| CN114182169A (en) * | 2021-11-22 | 2022-03-15 | 燕山大学 | Thick-wall large-caliber X80M-grade plate for hot-bending elbow and manufacturing method thereof |
| CN115652190B (en) * | 2022-09-20 | 2023-11-28 | 包头钢铁（集团）有限责任公司 | Production method of hot rolled steel strip for Nb-Ti-Mo component system L415M-RW hot-bending pipe |
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| JP2003286541A (en) * | 2002-03-28 | 2003-10-10 | Nisshin Steel Co Ltd | Steel as material for band saw blade body showing excellent producibility and fatigue characteristics and steel plate |
| CN103981460A (en) * | 2014-05-30 | 2014-08-13 | 秦皇岛首秦金属材料有限公司 | Hot rolling flat steel for high toughness X80 elbow and production method thereof |
| CN103981463A (en) * | 2014-05-30 | 2014-08-13 | 秦皇岛首秦金属材料有限公司 | X70 bend hot-rolled flat plate having excellent toughness and production method thereof |
| CN109402511B (en) * | 2018-11-19 | 2020-12-29 | 包头钢铁（集团）有限责任公司 | Hot-rolled steel strip for hydrogen sulfide corrosion resistant welded pipe and manufacturing method thereof |
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