CN110863145A - ERW submarine pipeline steel plate coil and production process thereof - Google Patents
ERW submarine pipeline steel plate coil and production process thereof Download PDFInfo
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- C22C38/00—Ferrous alloys, e.g. steel alloys
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- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- 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
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- 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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- 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
- C21D2211/009—Pearlite
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Abstract
The invention discloses an ERW submarine pipeline steel plate coil and a production process thereof, and belongs to the technical field of submarine pipeline steel. The main components and the mass percentage are as follows: 0.040% -0.070%, Si: 0.10-0.20%, Mn: 1.40% -1.60%, Nb: 0.020% -0.040%, V: 0.020-0.040%, Ti: 0.010% -0.030%, Mo: 0.08-0.15%, Als: 0.020-0.050%, S is less than or equal to 0.0020%, and P is less than or equal to 0.013%; the balance of Fe and inevitable impurity elements; the method is characterized by developing a steel plate coil suitable for ERW submarine pipelines with small pipe diameters (such as phi 219.1-phi 273.1mm), which contains very low carbon content, has extremely low S content (less than 0.0020%) and P content (less than 0.013%), adjusting and controlling rolling and cooling processes under a TMCP process system to obtain uniform ferrite and fine pearlite structures, wherein the material has 10-12-grade grain size, no more than 3.0-grade banded structures and low non-metallic inclusions, so that the material has yield strength higher than 450MPa and elongation more than 30%, impact power at-30 ℃ is more than 300J, and the material has good toughness.
Description
Technical Field
The invention belongs to the technical field of submarine pipeline steel, and particularly relates to an ERW submarine pipeline steel plate coil and a production process thereof.
Background
ERW (electric Resistance welding), means straight seam electric Resistance welding, and the ERW steel pipe is mainly used for conveying gas-liquid objects such as oil, natural gas and the like, can meet various requirements of high pressure and low pressure, and currently occupies a great position in the field of conveying pipes in the world. The ERW steel pipe has strict interval control requirements on yield strength and tensile strength, the maximum yield strength and the maximum tensile strength of the ERW steel pipe in the transverse direction and the longitudinal direction do not exceed 120MPa of the minimum yield strength (450MPa) and the tensile strength (535MPa) specified by API standards and technical protocols, and at the moment, the performance fluctuation of the product is small, and the transverse performance and the longitudinal performance are stable. For the small pipe diameter (such as phi 219.1-phi 273.1mm) of ERW submarine pipeline steel, the longitudinal yield strength of a hot-rolled coil is greatly enhanced after the pipe is manufactured, the yield strength of the steel pipe is easily caused to exceed the range of the control requirement of a 120MPa interval, and a remedial measure of steel pipe heat treatment is needed for the small-pipe-diameter steel pipe with overhigh strength. Therefore, the development of the ERW submarine pipeline steel suitable for the small-pipe-diameter ERW can effectively reduce the production cost of the ERW small-pipe-diameter steel pipe, meets the development requirement of a submarine oil and gas transmission pipeline, and has wide application prospect.
In the prior art, the Chinese patent application numbers are: 201610951516.3, publication date is: 2018.05.04, discloses a technical scheme of an X65 grade steel plate for a low-cost subsea pipeline and a manufacturing method thereof, wherein the steel plate comprises the following chemical components in percentage by weight: c: 0.05-0.09%, Si: 0.10 to 0.30%, Mn: 1.40-1.60%, P: less than or equal to 0.018%, S: less than or equal to 0.008 percent, Ti: 0.008-0.020%, Als: 0.02-0.06%, Nb: 0.02-0.04%, Cr: 0.10-0.15%, N: less than or equal to 0.008 percent, Pcm less than or equal to 0.20 percent, and the balance of iron and inevitable elements. The structure of the designed X65-grade low-cost submarine pipeline steel plate is a mixed structure of acicular ferrite and a small amount of ferrite, wherein the volume percentage of the ferrite is 4-8%, and the produced pipeline steel has high strength and good weldability; however, the patent relates to a low-cost hot rolled coil of line steel for spiral submerged arc welding and a manufacturing method thereof, which cannot be applied to ERW line steel coils.
The Chinese patent application numbers are: 201210492187.2, publication date is: 2014.06.04, the thick-wall high DWTT performance X65-70 subsea pipeline steel and the manufacturing method thereof, discloses the thick-wall high DWTT performance X65-70 subsea pipeline steel and the manufacturing method thereof, the steel comprises the following main components by weight percent: c: 0.03-0.050%, Si: less than or equal to 0.25 percent, Mn: 1.47-1.70%, P: less than or equal to 0.010 percent, S: less than or equal to 0.001 percent, Ti: 0.006-0.010%, Cr: 0.10-0.20%, Cu: 0.12-0.20%, Ni: 0.36-0.45%, Al: 0.025-0.045%, Ca: 0.0008-0.0025%, N: less than or equal to 0.0035 percent, O: less than or equal to 0.0025 percent, Nb: 0.040-0.0.050%, and the balance of Fe and inevitable impurities; and Ceq is 0.34-0.040, Pcm is 0.13-0.17. The method is suitable for UOE welded pipes with the thick walls larger than 25.4mm, and the C content is low; but more alloying elements Ni and Cu are needed to be added to ensure the strength, and the alloy cost is high.
The Chinese patent application numbers are: 201510650881.6, publication date is: 2015.12.09A high-strength economical steel for submarine pipeline, which contains C: 0.050 to 0.080%, Si: 0.10 to 0.30%, Mn: 0.80-1.30%, P: less than or equal to 0.015%, S: less than or equal to 0.0015 percent, Cr: 0.10 to 0.30%, Nb: 0.015 to 0.040%, V: 0.020 to 0.045%, Ti: 0.010-0.025%, Al: 0.010-0.050%, N: less than or equal to 0.008 percent; in the process, the cooling rate is not lower than 70 ℃/s, the final cooling temperature is 300-450 ℃, and the coiling temperature is 200-350 ℃. The content of C in the alloy is low, more alloy elements need to be added to ensure the strength, and the alloy cost is high; the cooling speed is fast, the control is difficult, the coiling temperature is low, and the requirement on a coiling machine is high.
Disclosure of Invention
1. Problems to be solved
Aiming at the problem that the transverse and longitudinal strength of a steel pipe is greatly improved after the existing ERW submarine pipeline steel is made into a pipe, the invention provides an ERW submarine pipeline steel plate coil and a production process thereof, develops an ERW submarine pipeline steel plate coil suitable for small pipe diameter (such as phi 219.1-phi 273.1mm) and solves the problem.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention relates to an ERW submarine pipeline steel plate coil which comprises the following chemical components in percentage by mass: c: 0.040% -0.070%, Si: 0.10-0.20%, Mn: 1.40% -1.60%, Nb: 0.020% -0.040%, V: 0.020-0.040%, Ti: 0.010% -0.030%, Mo: 0.08-0.15%, Als: 0.020-0.050%, S is less than or equal to 0.0020%, and P is less than or equal to 0.013%; the balance of Fe and inevitable impurity elements.
As a further explanation of the invention, the thickness of the plate coil is 11.0-14.6 mm.
As a further illustration of the invention, the metallographic structure of the ERW submarine pipeline steel plate coil is uniform ferrite and fine pearlite, the ferrite grain size is 10-12 grades, and the banded structure is not more than 3.0 grades.
The invention relates to a production process of an ERW submarine pipeline steel plate coil, which comprises the following steps:
s1, pretreating molten iron;
s2, carrying out composite blowing at the top and the bottom of the converter;
s3, fine adjustment of alloy;
s4, LF and RH furnace refining;
s5, continuous casting of the plate blank;
s6, heating by a heating furnace;
s7, rough rolling and finish rolling;
s8, coiling after laminar cooling, wherein the laminar cooling speed is 20-30 ℃/S, and the coiling temperature after laminar cooling is 500-600 ℃.
As a further description of the present invention, in step S1, the molten iron pretreatment is performed by pre-slagging and post-slagging, and after the molten iron is desulfurized, the mass percentage of [ S ] is less than or equal to 0.0050%.
As a further explanation of the present invention, in step S3, aluminum particles are added to the molten iron, and the top dross is reduced by strong stirring.
As a further description of the invention, in step S4, the ladle top slag is fully reduced by LF furnace treatment, and chemical elements C, Si, Mn, Nb, Mo, V are adjusted to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
As a further illustration of the invention, in the step S5, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled by stacking, and the stacking slow cooling time is more than or equal to 48 hours.
In step S6, the cast slab is placed in a heating furnace to be heated, and the tapping temperature of the cast slab is controlled to 1170-1210 ℃.
As a further illustration of the present invention, in step S7, the rolling temperature in the rough rolling stage is in the range of 1000 to 1060 ℃; the initial rolling temperature of finish rolling is less than 1010 ℃, and the final rolling temperature is 820-880 ℃.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention relates to an ERW submarine pipeline steel plate coil, aiming at providing a component design, a hot rolling process, a microstructure and a performance control technology for producing submarine pipeline steel on a hot rolling production line, developing an ERW submarine pipeline steel plate coil suitable for small pipe diameters (such as phi 219.1-phi 273.1mm), containing very low carbon content, having extremely low S content (less than 0.0020%) and P content (less than 0.013%), adjusting and controlling rolling and cooling processes under a TMCP process system to obtain uniform ferrite and fine pearlite structures, wherein the material has a grain size of 10-12 levels, a banded structure not more than 3.0 levels and low non-metallic inclusions, has yield strength higher than 450MPa and elongation more than 30%, has impact power more than 300J at-30 ℃ and has good toughness;
(2) the ERW submarine pipeline steel plate coil provided by the invention has the following main microstructures that uniform and fine acicular ferrite and fine pearlite are adopted, the grain size is 10-12 grades, and the transverse mechanical property is as follows: yield strength rt 0.5: 453-510 MPa, tensile strength Rm: 541-626 MPa, elongation after fracture A50: 32% -45%; longitudinal mechanical properties: yield strength rt 0.5: 450-495 MPa, tensile strength Rm: 542-610 MPa, elongation after fracture A50: 33% -47%; the transverse yield strength and the longitudinal yield strength of the plate coil are both higher than the design requirement of 450MPa, the transverse yield strength and the longitudinal yield strength are relatively similar, the integral mechanical property of the plate coil is relatively uniform, after the steel plate is made into a tube, the transverse strength and the longitudinal strength of the obtained steel tube are both less than 120MPa, and particularly, for small pipe diameters (such as phi 219.1-phi 273.1mm), the ERW submarine pipeline does not need to be subjected to heat treatment at the later stage, the ERW submarine pipeline can be directly used, and the energy and the cost are saved;
(3) according to the ERW submarine pipeline steel plate coil, the addition of alloy elements is reduced, the alloy cost is saved to a certain extent, the mechanical property stability of the plate coil can be ensured, a proper production process is formulated according to the chemical components of the plate coil, the toughening effect of the alloy elements and the hot rolling process is fully exerted by utilizing a proper hot rolling reduction system and a proper cooling process, the excellent performance is obtained, and the production cost is reduced;
(4) according to the production process of the ERW submarine pipeline steel plate coil, the content of harmful elements such as S, P, N, H and the like is strictly controlled in component treatment of the plate coil, and the content of the harmful elements is strictly controlled in the smelting process, so that the production control of clean steel is realized, and the performance quality of the plate coil is improved;
(5) according to the production process of the ERW submarine pipeline steel plate coil, the temperature of molten steel in a tundish is controlled in the continuous casting process, the occurrence of center segregation phenomenon is reduced, the temperature of rough rolling and finish rolling is controlled in the rolling process, austenite grains are obviously refined through repeated deformation and recrystallization in the rough rolling process, deformation and phase change occur simultaneously in the finish rolling process, the austenite grains are elongated to generate a slip zone, favorable conditions are provided for ferrite nucleation due to increase of austenite grain boundaries and occurrence of the slip zone, fine-grained ferrite is further obtained, island-shaped martensite is prevented, rapid cooling is set after rolling, the cooling speed is 20-30 ℃/s, and final cooling is 500-660 ℃.
Drawings
The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for illustrative purposes only and thus do not limit the scope of the present invention. Furthermore, unless otherwise indicated, the drawings are intended to be illustrative of the structural configurations described herein and are not necessarily drawn to scale.
FIG. 1 is a schematic metallographic structure of an ERW subsea pipeline steel plate coil of example 1 according to the present invention;
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.
The main chemical components and the mass percentage content of the ERW submarine pipeline steel plate coil are shown in the table 1:
TABLE 1 chemical compositions and weight percentages (mass%, balance Fe) of the examples and comparative examples
| C | Si | Mn | Nb | V | Ti | Mo | Als | P | S | |
| Example 1 | 0.048 | 0.12 | 1.60 | 0.039 | 0.040 | 0.016 | 0.15 | 0.020 | 0.0097 | 0.0012 |
| Example 2 | 0.040 | 0.19 | 1.55 | 0.040 | 0.034 | 0.030 | 0.12 | 0.034 | 0.0062 | 0.0009 |
| Example 3 | 0.059 | 0.15 | 1.50 | 0.030 | 0.020 | 0.010 | 0.08 | 0.040 | 0.0065 | 0.0008 |
| Example 4 | 0.070 | 0.10 | 1.40 | 0.026 | 0.030 | 0.021 | 0.11 | 0.034 | 0.0062 | 0.0009 |
| Example 5 | 0.065 | 0.20 | 1.48 | 0.020 | 0.026 | 0.016 | 0.10 | 0.050 | 0.0092 | 0.0012 |
| Example 6 | 0.055 | 0.16 | 1.50 | 0.029 | 0.028 | 0.015 | 0.10 | 0.035 | 0.0072 | 0.0007 |
| Example 7 | 0.052 | 0.15 | 1.51 | 0.030 | 0.029 | 0.014 | 0.11 | 0.036 | 0.0065 | 0.0008 |
| Comparative example | 0.039 | 0.18 | 1.49 | 0.050 | 0.027 | 0.018 | 0.14 | - | 0.0090 | 0.0008 |
The contents of the elements in the above examples all satisfy the following ranges:
c: 0.040% -0.070%, Si: 0.10-0.20%, Mn: 1.40% -1.60%, Nb: 0.020% -0.040%, V: 0.020-0.040%, Ti: 0.010% -0.030%, Mo: 0.08-0.15%, Als: 0.020-0.050%, S is less than or equal to 0.0020%, and P is less than or equal to 0.013%; the balance of Fe and inevitable impurity elements.
The specific effects of the element composition in the scheme are as follows:
c: the steel is interstitial atoms in steel, plays a very important role in the strength (yield strength and tensile strength) and welding performance of materials, in an ERW submarine pipeline steel plate coil, on one hand, the strength needs to be ensured, a high carbon content is needed, the C content needs to ensure that the lower limit is 0.04%, but the ERW submarine pipeline steel plate coil needs to have high impact toughness and welding performance due to environmental factors, but the C content is increased, the toughness, the welding performance and the acid resistance of the materials are all reduced, and therefore, the C content needs to ensure that the upper limit is 0.07%.
Si: the steel has the solid solution strengthening effect in steel, so that the strength of a plate coil is improved, the ferrite forming range can be expanded, the rolling process window is favorably expanded, but the excessively high Si content can influence the surface quality of steel and damage the service performance of the ERW submarine pipeline steel plate coil, so that the Si content needs to be controlled to be 0.10-0.20 percent to meet the use requirement.
Mn: the Mn-free steel is a cheap element, can improve the strength of steel through solid solution strengthening, can promote the dissolution of a carbonitride precipitated phase during heating, can inhibit the precipitation of the precipitated phase during rolling, is beneficial to keeping more precipitated elements precipitated in ferrite during cooling after rolling, and enhances the precipitation strengthening, but the excessive Mn element is easy to cause central segregation of a plate blank, and if the strength and other properties of an ERW submarine pipeline steel plate coil are ensured, the Mn content needs to be controlled to be 1.40-1.60%.
Nb: the micro-alloy is an indispensable micro-alloy element in the pipeline steel, can simultaneously improve the strength and the low-temperature toughness, and can accelerate the austenitizing process and refine grains in a solid melting state; in addition, in the welding process, the precipitation of niobium atoms can prevent the coarsening of austenite grains during heating and improve the welding performance, so that the Nb content is controlled to be 0.020-0.040%.
V: has higher precipitation strengthening and weaker grain refining effect, and V is not used alone and is combined with Nb in the design of pipeline steel. The strength of the coil can be improved by precipitation strengthening by adding a trace amount of V into the pipeline steel, so that the content of V is controlled to be 0.020-0.040%.
Ti: forming compounds with C, N, etc. in steel, and fixing N in steel by Ti by micro-titanium treatment for reducing the content of nitrogen dissolved in steel; the addition of a trace amount of titanium into the steel can improve the strength and toughness of the steel plate, so that the content of Ti is controlled to be 0.010-0.030%.
Mo: is one of the main alloy elements in the pipeline steel, Mo in the steel is beneficial to the generation of an acicular ferrite structure, and can obtain high strength under the condition of extremely low carbon content, so that the Mo content is controlled to be 0.08-0.15%.
Al: the aluminum oxide is a deoxidizing element in steel, generates aluminum oxide, can reduce oxide inclusions in the steel and can refine grains, but when the aluminum content is too high, the effect of refining the grains is weakened, the viscosity of the aluminum oxide is high, excessive aluminum oxide in the molten steel can increase the viscosity of the molten steel, and the aluminum oxide adversely affects casting, so the Al content is controlled to be 0.020-0.050%.
P, S element is harmful impurity element, which is easy to cause segregation and aggregation, especially the submarine pipeline steel has higher requirement for composition and mechanical property of steel, so the requirement for P, S content is lower, therefore P, S content is controlled to be P less than 0.013%, S less than 0.0020%.
It should be noted that an ERW subsea pipeline steel plate coil of the present invention is intended to provide a composition design, a hot rolling process, a microstructure and a performance control technology for producing subsea pipeline steel in a hot rolling production line, and develop an ERW subsea pipeline steel plate coil suitable for small pipe diameter (e.g. Φ 219.1- Φ 273.1mm), wherein the pipe steel with small pipe diameter has an increased difference in transverse and longitudinal strength after pipe making, very low carbon content, extremely low S content (less than 0.0020%) and P content (less than 0.013%) to obtain a uniform ferrite + fine pearlite structure, as shown in fig. 1, the material has a grain size of 10-12 levels, a banded structure not more than 3.0 levels, and low non-metallic inclusions, so that the material has a yield strength higher than 450MPa, an elongation greater than 30%, and a punching work at-30 ℃ greater than 300J, and has good toughness. The transverse mechanical properties are as follows: yield strength rt 0.5: 453-510 MPa, tensile strength Rm: 541-626 MPa, elongation after fracture A50: 32% -45%; longitudinal mechanical properties: yield strength rt 0.5: 450-495 MPa, tensile strength Rm: 542-610 MPa, elongation after fracture A50: 33% -47%; the transverse yield strength and the longitudinal yield strength of the plate coil are both higher than the design requirement of 450MPa, the transverse yield strength and the longitudinal yield strength are relatively similar, the integral mechanical property of the plate coil is relatively uniform, after the steel plate is made into a pipe, the transverse strength and the longitudinal strength of the obtained steel pipe are both less than 120MPa, and particularly, for small pipe diameters (such as phi 219.1-phi 273.1mm), the ERW submarine pipeline does not need to be subjected to heat treatment in the later stage, the ERW submarine pipeline can be directly used, and the energy and the cost are saved.
The invention relates to a production process of an ERW submarine pipeline steel plate coil, which comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) placing the casting blank into a heating furnace for heating, controlling the tapping temperature of the casting blank to 1170-1210 ℃, and keeping the temperature for not less than 60 min. The main purpose is to ensure the complete austenitization of the material, fully dissolve alloy elements and inhibit the excessive growth of austenite grains.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is within the range of 1000-1060 ℃; the initial rolling temperature of finish rolling is less than 1010 ℃, and the final rolling temperature is 820-880 ℃. In the two-stage rolling process, the rough rolling is rolling in a recrystallization region, the rolling temperature is controlled to be 1000-1060 ℃, and austenite grains are obviously refined through repeated deformation and recrystallization; the finish rolling is to control the rolling temperature at 900-1000 ℃, and is a stage for simultaneously carrying out deformation and phase change, austenite grains are elongated in the stage, a slip zone is generated simultaneously, favorable conditions are provided for ferrite nucleation due to increase of austenite grain boundaries and occurrence of the slip zone, and then fine-grained ferrite is obtained.
S8, coiling after laminar cooling, wherein the laminar cooling speed is 20-30 ℃/S, and the coiling temperature after laminar cooling is 500-600 ℃. For the ERW submarine pipeline steel suitable for small pipe diameter, the final cooling temperature is not low enough to prevent island-shaped martensite, therefore, the steel is set to be rapidly cooled after rolling, the cooling speed is 20-30 ℃/s, the final cooling is carried out to 500-660 ℃, the transverse and longitudinal mechanical property fluctuation of the ERW submarine pipeline formed by rolling the ERW submarine pipeline steel plate is small, and the service performance is good.
And cooling the coiled sheet produced by the process to room temperature to prepare the ERW submarine pipeline.
Example 1
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 1 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) putting the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1210 ℃, and keeping the temperature for 70 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1060 ℃; the initial rolling temperature of finish rolling is 1000 ℃, and the final rolling temperature is 880 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 30 ℃/S, and the coiling temperature after laminar cooling is 540 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 11.1 mm.
Example 2
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 2 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) placing the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1190 ℃, and keeping the temperature for 75 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1000 ℃; the initial rolling temperature of finish rolling is 900 ℃, and the final rolling temperature is 850 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 20 ℃/S, and the coiling temperature after laminar cooling is 580 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 12.7 mm.
Example 3
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 3 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) placing the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1200 ℃, and keeping the temperature for 65 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1020 ℃; the initial rolling temperature of finish rolling is 950 ℃, and the final rolling temperature is 860 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 30 ℃/S, and the coiling temperature after laminar cooling is 500 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 13.1 mm.
Example 4
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 4 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) putting the casting blank into a heating furnace for heating, controlling the tapping temperature of the casting blank to 1170 ℃, and keeping the temperature for 70 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1050 ℃; the initial rolling temperature of the finish rolling is 960 ℃, and the final rolling temperature is 840 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 25 ℃/S, and the coiling temperature after laminar cooling is 600 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 14.3 mm.
Example 5
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 5 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) putting the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1190 ℃, and keeping the temperature for 90 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1010 ℃; the initial rolling temperature of finish rolling is 930 ℃, and the final rolling temperature is 820 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 30 ℃/S, and the coiling temperature after laminar cooling is 660 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 14.6 mm.
Example 6
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 6 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) placing the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1190 ℃, and keeping the temperature for 75 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1030 ℃; the initial rolling temperature of finish rolling is 910 ℃, and the final rolling temperature is 850 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 28 ℃/S, and the coiling temperature after laminar cooling is 580 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 11.0 mm.
Example 7
The main chemical components and mass percentages of the ERW subsea pipeline steel plate coil of the embodiment are shown in the embodiment 7 in the table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) putting the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1190 ℃, and keeping the temperature for 80 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1060 ℃; the initial rolling temperature of finish rolling is 980 ℃, and the final rolling temperature is 860 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 30 ℃/S, and the coiling temperature after laminar cooling is 590 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 12.7 mm.
Comparative example
The ERW subsea pipeline steel plate coil of the embodiment has the main chemical components and mass percentages shown in comparative examples in Table 1.
The production process of the ERW submarine pipeline steel plate coil comprises the following steps:
s1, pretreating molten iron; pre-treating molten iron for pre-slagging and post-slagging, wherein after molten iron is desulfurized, the mass percentage of S is less than or equal to 0.0050%.
S2, carrying out composite blowing at the top and the bottom of the converter; intensified dephosphorization, and deoxidation microalloying in tapping.
S3, fine adjustment of alloy; adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
S4, LF and RH furnace refining; performing LF furnace treatment, fully reducing the steel ladle top slag, and adjusting chemical elements C, Si, Mn, Nb, Mo and V to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
S5, continuous casting of the plate blank; the tundish target temperature is controlled to be the liquidus temperature plus the molten steel superheat degree, the overhigh superheat degree is unfavorable for controlling the internal quality of a casting blank, the overlow superheat degree is easy to cause low-temperature flow accumulation, the removal of impurities is not good, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled in a stacking mode, the stacking slow cooling time is not less than 48h, the central segregation of the casting blank can be reduced, the surface of the casting blank is inspected and subjected to corner cutting treatment after cooling, and the surface quality of the casting blank is improved.
S6, heating by a heating furnace; and (3) putting the casting blank into a heating furnace for heating, controlling the discharging temperature of the casting blank to be 1185 ℃, and keeping the temperature for 70 min.
S7, rough rolling and finish rolling; the rolling temperature in the rough rolling stage is 1060 ℃; the initial rolling temperature of finish rolling is 1000 ℃, and the final rolling temperature is 840 ℃.
And S8, coiling after laminar cooling, wherein the laminar cooling speed is 30 ℃/S, and the coiling temperature after laminar cooling is 407 ℃.
The thickness of the ERW submarine pipeline steel plate coil obtained by the production process is 20.6 mm.
The mechanical properties of the above examples and comparative examples are shown in table 2:
TABLE 2 mechanical Properties of examples and comparative examples
In the above table: rt0.5: yield strength, Rm: tensile strength, A50: and (3) elongation percentage.
The results of the V-type impact energy test performed on the steels of the examples of the present invention and the comparative examples are shown in Table 3:
TABLE 3 impact work value of each example and comparative example
The results of the examination of non-metallic inclusions were obtained for the steels of examples of the present invention and comparative examples, and are shown in Table 4:
TABLE 4 non-metallic inclusions of examples and comparative examples
In the above table: class a (sulfides) -individual gray inclusions with high ductility, with a wide range of aspect ratios (length/width), typically with rounded ends.
Class B (alumina class) -most undeformed, angular, small aspect ratio (typically <3), black or bluish particles, are aligned in a row (at least 3 particles) in the rolling direction.
Class C (silicates) -single black or dark gray inclusions with high ductility, with a wide range of aspect ratios (typically ≧ 3), typically sharp-edged at the ends.
Class D (spherical oxides) -undeformed, angular or rounded, with a small aspect ratio (generally <3), black or bluish DS class (single-particle spherical class) -a round or nearly round single-particle inclusion with a diameter of > 13 Pm.
The above-mentioned non-metallic inclusions in the steel product are detrimental to the properties of the steel product, and the lower the non-metallic inclusions, the better the properties of the steel product.
The grain size and the band structure were measured for the steels of the examples and comparative examples of the present invention, and the results are shown in Table 5:
TABLE 5 grain size and band structure of test steels of examples and comparative examples
| Sample numbering | Grain size | Strip tissue |
| Example 1 | 11 | 1 |
| Example 2 | 12 | 1 |
| Example 3 | 11.5 | 2 |
| Example 4 | 10.5 | 1 |
| Example 5 | 11.5 | 2 |
| Example 6 | 11.5 | 1 |
| Example 7 | 11.0 | 1 |
| Comparative example | 10～12 | ≤1.0 |
In conclusion, the properties of the steel of the embodiment obtained according to the design range of the chemical components of the steel grade and the rolling process control technology are as follows: transverse mechanical properties: rt 0.5: 466-509 MPa, Rm: 557 to 605MPa, A50: 35% -45%; longitudinal mechanical properties: rt 0.5: 452-485 MPa, Rm: 554-589 MPa, A50: 37% -45%; 338-373J of transverse impact energy and 335-382J of longitudinal impact energy at the temperature of minus 30 ℃; the mechanical property of the finished product is stable, the grain size is 10-12 grades, and the banded structure is 1-2 grades.
The mechanical properties of the coil after ERW pipe making are shown in Table 6:
TABLE 6 mechanical Properties of the examples of steel pipes
In the above table: rt0.5: yield strength, Rm: tensile strength, A50: and (3) elongation percentage.
Comparing table 2 and table 6, it can be found that after the coiled sheet is subjected to ERW pipe making, the transverse and longitudinal strength rises less than 120MPa, the transverse yield strength rises 15-45 MPa, the longitudinal yield strength rises 50-80 MPa, and the minimum yield strength (450MPa) and the tensile strength (535MPa) specified by API standards and technical protocols are within 120 MPa. The product has stable performance, does not need to be subjected to heat treatment subsequently to reduce the strength, and saves energy and cost.
Claims (10)
1. An ERW submarine pipeline steel plate coil is characterized by comprising the following chemical components in percentage by mass: c: 0.040% -0.070%, Si: 0.10-0.20%, Mn: 1.40% -1.60%, Nb: 0.020% -0.040%, V: 0.020-0.040%, Ti: 0.010% -0.030%, Mo: 0.08-0.15%, Als: 0.020-0.050%, S is less than or equal to 0.0020%, and P is less than or equal to 0.013%; the balance of Fe and inevitable impurity elements.
2. The ERW subsea pipeline steel coil in accordance with claim 1, wherein said coil has a thickness of 11.0-14.6 mm.
3. The ERW subsea pipeline steel plate roll according to claim 1, wherein the ERW subsea pipeline steel plate roll has a metallographic structure of uniform ferrite and fine pearlite, a ferrite grain size of 10-12 grade, and a banded structure of not more than 3.0 grade.
4. A production process of an ERW submarine pipeline steel plate coil is characterized by comprising the following steps:
s1, pretreating molten iron;
s2, carrying out composite blowing at the top and the bottom of the converter;
s3, fine adjustment of alloy;
s4, LF and RH furnace refining;
s5, continuous casting of the plate blank;
s6, heating by a heating furnace;
s7, rough rolling and finish rolling;
s8, coiling after laminar cooling, wherein the laminar cooling speed is 20-30 ℃/S, and the coiling temperature after laminar cooling is 500-600 ℃.
5. The production process of the ERW submarine pipeline steel plate coil according to claim 4, wherein in step S1, the molten iron pretreatment is pre-drossing and post-drossing, and after the molten iron desulfurization, the [ S ] is less than or equal to 0.0050% by mass.
6. The production process of the ERW subsea pipeline steel plate coil as claimed in claim 4, wherein in step S3, adding aluminum particles into the molten iron, and strongly stirring to reduce the top slag.
7. The production process of the ERW submarine pipeline steel plate coil according to claim 4, wherein in step S4, the LF furnace is used for processing, the ladle top slag is fully reduced, and chemical elements C, Si, Mn, Nb, Mo and V are adjusted to target values; and (3) RH furnace treatment, adjusting the chemical components Als and Ti to target values, deeply degassing for more than or equal to 12min, alloying, feeding a calcium line after the end point target [ H ] is less than or equal to 1.5ppm, controlling the content of Ca to be 15-30 ppm, and feeding the calcium line for more than or equal to 10min after the calcium line is broken.
8. The production process of the ERW submarine pipeline steel plate coil according to claim 4, wherein in step S5, the temperature of the continuous casting tundish is controlled to be 15-30 ℃ above the liquidus, dynamic soft reduction and electromagnetic stirring are adopted, the casting blank is slowly cooled by stacking, and the slow cooling time of the stacking is not less than 48 h.
9. The production process of the ERW submarine pipeline steel plate coil according to claim 4, wherein in the step S6, the casting blank is placed into a heating furnace to be heated, and the tapping temperature of the casting blank is controlled to be 1170-1210 ℃.
10. The production process of the ERW subsea pipeline steel plate coil as claimed in claim 4, wherein in step S7, the rolling temperature in the rough rolling stage is in the range of 1000-1060 ℃; the initial rolling temperature of finish rolling is less than 1010 ℃, and the final rolling temperature is 820-880 ℃.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111979497A (en) * | 2020-09-28 | 2020-11-24 | 马鞍山钢铁股份有限公司 | Submarine pipeline steel plate coil with excellent low-temperature CTOD (carbon dioxide optical density) performance and production process thereof |
| CN113025910A (en) * | 2021-03-10 | 2021-06-25 | 包头钢铁（集团）有限责任公司 | Preparation method of high-grade hot-bending bend steel strip |
| CN114480975A (en) * | 2022-02-23 | 2022-05-13 | 马鞍山钢铁股份有限公司 | Economical X65-grade acid-resistant pipeline steel plate coil and manufacturing method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110241360A (en) * | 2019-07-30 | 2019-09-17 | 马鞍山钢铁股份有限公司 | A kind of bigbore ERW submerged pipeline hot-rolled steel coiled sheet and preparation method thereof of heavy wall |
| CN110273109A (en) * | 2019-07-30 | 2019-09-24 | 马鞍山钢铁股份有限公司 | A kind of 450MPa grades of submerged pipeline roll of steel plate and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110241360A (en) * | 2019-07-30 | 2019-09-17 | 马鞍山钢铁股份有限公司 | A kind of bigbore ERW submerged pipeline hot-rolled steel coiled sheet and preparation method thereof of heavy wall |
| CN110273109A (en) * | 2019-07-30 | 2019-09-24 | 马鞍山钢铁股份有限公司 | A kind of 450MPa grades of submerged pipeline roll of steel plate and preparation method thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111979497A (en) * | 2020-09-28 | 2020-11-24 | 马鞍山钢铁股份有限公司 | Submarine pipeline steel plate coil with excellent low-temperature CTOD (carbon dioxide optical density) performance and production process thereof |
| CN113025910A (en) * | 2021-03-10 | 2021-06-25 | 包头钢铁（集团）有限责任公司 | Preparation method of high-grade hot-bending bend steel strip |
| CN114480975A (en) * | 2022-02-23 | 2022-05-13 | 马鞍山钢铁股份有限公司 | Economical X65-grade acid-resistant pipeline steel plate coil and manufacturing method thereof |
| CN114480975B (en) * | 2022-02-23 | 2023-02-28 | 马鞍山钢铁股份有限公司 | Economical X65-grade acid-resistant pipeline steel plate coil and manufacturing method thereof |
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Application publication date: 20200306 |