CN114892102A - Economical steel plate for large-thickness pipe fitting and manufacturing method thereof - Google Patents
Economical steel plate for large-thickness pipe fitting and manufacturing method thereof Download PDFInfo
- Publication number
- CN114892102A CN114892102A CN202210591815.6A CN202210591815A CN114892102A CN 114892102 A CN114892102 A CN 114892102A CN 202210591815 A CN202210591815 A CN 202210591815A CN 114892102 A CN114892102 A CN 114892102A
- Authority
- CN
- China
- Prior art keywords
- equal
- less
- steel plate
- thickness
- percent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- C22C38/36—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.7% by weight of carbon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- 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
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- 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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention provides an economical steel plate for large-thickness pipe fittings and a production method thereof, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.06-0.09%, Si: 0.15-0.30%, Mn: 1.55-1.65%, P is less than or equal to 0.012%, S is less than or equal to 0.002%, Al: 0.025 to 0.045%, Nb: 0.035 to 0.045%, Ti: 0.010-0.025%, Cr: 0.25 to 0.35 percent of the total weight of the alloy, less than or equal to 0.0030 percent of N, less than or equal to 0.0020 percent of O, less than or equal to 0.00015 percent of H, and the balance of Fe and inevitable impurities. The thickness of the steel plate produced by the method is 30-50mm, the quenching and tempering performance of the steel plate and the sample has higher strength and good low-temperature toughness, and the method can be widely applied to the aspects of pipe fitting steel and the like in the oil and gas transmission industry and has good popularization significance.
Description
Technical Field
The invention belongs to the technical field of medium and heavy plate production by continuous casting, and particularly relates to an economical large-thickness steel plate for a pipe fitting with the thickness of 30-50mm and a manufacturing method thereof.
Background
The pipe fitting plays roles of changing direction, strengthening and the like in a pipeline, is an important structural member and mainly comprises a tee joint, an end socket, a bent pipe and the like, the high-strength pipe fitting steel is a new variety with high technical content and high added value, and the high-strength pipe fitting steel has high strength, good extensibility, cold bending performance, welding performance and low-temperature impact resistance and is mainly applied to the natural gas and oil transportation industry. In practical application, after the high-strength pipe steel is subjected to workpiece quenching and tempering, the high-strength pipe steel can be applied to a more complex service environment, and in order to ensure the excellent performance of the pipe steel, a large amount of alloy is added in component design, so that the cost of the pipe steel is increased.
The patent "a thick plate for pipeline steel with excellent plasticity and toughness and a production method thereof" (CN 111996449B), although the patent has higher strength and toughness, expensive alloy elements such as Mo and Ni are added in the component design, the design cost is higher, the component design adopts the ultra-low carbon design, and the smelting difficulty in the industrial production is very large.
The patent "a low-cost wear-resisting pipe fitting steel X65 steel plate and its production method" (CN 103725974B), this patent composition design adopts Cr, V to replace Mo, Ni to reduce the cost, the process adopts the controlled rolling controlled cooling after the quenching and tempering heat treatment process, but does not mention the steel plate intensity and toughness condition in the text, can't guarantee the steel plate thickness 1/2 position has good low-temperature toughness either.
Disclosure of Invention
The invention aims to provide an economical steel plate for large-thickness pipe fittings and a manufacturing method thereof, wherein a steel plate with the thickness of 30-50mm is produced by matching reasonable components, smelting control, controlled rolling and controlled cooling and heat treatment processes, the quenching and tempering strength of the steel plate and a sample exceeds the requirement of L450 steel grade, and the low-temperature impact performance of the steel plate and the sample at the position of the quenching and tempering thickness 1/2 can be simultaneously ensured.
In order to solve the technical problems, the invention adopts the technical scheme that: the economical steel plate for the large-thickness pipe fitting comprises the following chemical components in percentage by mass: c: 0.06-0.09%, Si: 0.15-0.30%, Mn: 1.55-1.65%, P is less than or equal to 0.012%, S is less than or equal to 0.002%, Al: 0.025 to 0.045%, Nb: 0.035 to 0.045%, Ti: 0.010-0.025%, Cr: 0.20-0.30%, N is less than or equal to 0.0030%, O is less than or equal to 0.0020%, H is less than or equal to 0.00015%, and the balance is Fe and inevitable impurities, and CEpcm is less than or equal to 0.18%.
The invention also discloses an economical steel plate for large-thickness pipe fittings and a manufacturing method thereof, and the economical steel plate is characterized in that: the production steps and parameters of the manufacturing method are as follows:
1. smelting: molten iron pretreatment → converter smelting → LF furnace treatment → RH vacuum treatment → continuous casting;
in the converter smelting, the tapping P is less than or equal to 0.010 percent, the tapping S is less than or equal to 0.003 percent, the point blowing is not allowed, the slag falling in the tapping process is avoided, and the aluminum wire is added in an argon station for deoxidation; in LF refining, large slag amount is adopted for slagging, and the white slag retention time is more than or equal to 17 min; RH vacuum pressure maintaining (less than or equal to 100 Pa) time is more than or equal to 12min, calcium treatment is carried out before tapping, static argon blowing time after wire feeding is more than or equal to 12min, the content of gas is strictly controlled, and the weight percentage content is as follows: n is less than or equal to 0.0030 percent, O is less than or equal to 0.0020 percent, and H is less than or equal to 0.00015 percent; controlling the superheat degree to be less than or equal to 20 ℃ in the continuous casting process, adopting secondary cooling electromagnetic stirring and solidification tail end soft reduction, and keeping constant drawing speed in the casting blank casting process, wherein the drawing speed range is 0.6-0.8 m/min, and the center segregation C class is less than or equal to 1.0;
2. heating: a walking beam type heating furnace is adopted, in order to prevent austenite grains from growing large, the heating temperature is not suitable to be too high, the temperature of a soaking section is controlled to be 1170-1230 ℃, the total heating time of a casting blank in the heating furnace is 260-300min, and the temperature of the casting blank is ensured to be uniform;
3. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1020-.
Wherein the yield strength of the steel plate is more than or equal to 469MPa, the tensile strength is more than or equal to 613MPa, the yield ratio is less than or equal to 0.77, the transverse impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ is more than or equal to 150J, the longitudinal impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ is more than or equal to 200J, and the DWTT at the temperature of 20 ℃ and at the temperature of 85 percent.
Further: the quenching temperature of the sample is 910-.
Further: the flaw detection result of the steel plate meets the I-level requirement of NB/T47013-.
Further: the thickness of the steel plate is 30-50mm, and the thickness of the continuous casting billet/the thickness of the finished steel plate is less than or equal to 8.
Through the process flow, the yield strength of the produced economical steel plate for the large-thickness pipe fitting is more than or equal to 469MPa, the tensile strength is more than or equal to 613MPa, the yield ratio is less than or equal to 0.77, the transverse impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ below zero is more than or equal to 150J, the longitudinal impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ below zero is more than or equal to 200J, and the DWTT at the temperature of 20 ℃ below zero is more than or equal to 85 percent. (ii) a The quenching temperature of the sample is 910-.
The invention has the advantages that:
1. through reasonable component system design and an optimal rolling and cooling control process, the produced economical large-thickness steel plate for the pipe fittings and the samples meet the requirement of L450 steel grade in API 5L standard after tempering, the actually produced steel plate can reach the yield strength of not less than 469MPa, the tensile strength of not less than 613MPa, the yield ratio of not more than 0.77, the yield strength of not less than 504MPa, the tensile strength of not less than 594MPa and the yield ratio of not more than 0.86 after the samples are tempered.
2. The economical steel plate for the large-thickness pipe fitting, which is produced by the invention, has good strength and excellent low-temperature impact performance at the position with the guaranteed thickness of 1/2, the transverse impact energy at the position with the thickness of 1/2-30 ℃ of the steel plate is more than or equal to 150J, the longitudinal impact energy at the position with the thickness of 1/2-30 ℃ of the steel plate is more than or equal to 200J, the DWTT at the temperature of-20 ℃ is more than or equal to 85 percent, the transverse impact energy at the position with the thickness of 1/2-30 ℃ of a sample after hardening and tempering is more than or equal to 220J, the longitudinal impact energy at the position with the thickness of 1/2-30 ℃ of the sample after hardening and tempering is more than or equal to 250J, and the DWTT at the temperature of-20 ℃ is more than or equal to 90 percent.
3. The steel plate for the economical large-thickness pipe fitting produced by the invention has the advantages that the alloy elements such as Mo, Ni and the like with high price are replaced by the alloy elements Nb and Cr with low price in the component design, and the cost is greatly reduced.
4. The thickness of the economical steel plate for large-thickness pipe fittings produced by the invention is 30-50mm, the thickness of the continuous casting blank/the thickness of the finished steel plate is less than or equal to 8.
5. The flaw detection result of the economical steel plate for the large-thickness pipe fitting produced by the invention meets the I-level requirement of NB/T47013-.
Drawings
Figure 1 example 1 a typical microstructure of an economical steel sheet 1/4 for large thickness pipe fittings.
Figure 2 example 1 a typical microstructure of an economical steel sheet 1/2 for large thickness pipe fittings.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1
The thickness of the economical steel plate for the large-thickness pipe fitting is 30mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.06%, Si: 0.25%, Mn: 1.65%, P: 0.010%, S: 0.002%, Al: 0.045%, Nb: 0.040%, Ti: 0.015%, Cr: 0.2%, N: 0.0030%, O: 0.0020%, 0.0001% of H, and the balance Fe and inevitable impurities, CEpcm = 0.16%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 17min, maintaining RH vacuum for 12min, and statically blowing argon for 18 min;
2. continuous casting: the superheat degree is 12 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class is 1.0;
3. heating: the temperature of the heating soaking section is 1170 ℃, and the total heating time of the casting blank in the heating furnace is 270 min;
4. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1020 ℃, the cumulative reduction rate is 68%, the final three-pass reduction rates are respectively 16%, 18% and 19%, the initial rolling temperature of finish rolling is 890 ℃, the final rolling temperature is 820 ℃, the cumulative reduction rate is 63%, and after the final pass is finished, rapid steel throwing is adopted to enable a steel plate to rapidly enter a controlled cooling zone to avoid crystal grain growth, and the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature of red returning of the steel plate is 600 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 474MPa, the tensile strength is 639MPa, the yield ratio is 0.74, the transverse impact energy at the thickness of 1/2 and the temperature of 30 ℃ below zero is 150J, the longitudinal impact energy at the thickness of 1/2 and the temperature of 30 ℃ below zero is 210J, and the DWTT at the temperature of 20 ℃ below zero is 86 percent; the samples are quenched at 910-; the standard is qualified according to NB/T47013-.
The microstructure observation of the steel plate produced by the invention adopting the component design and the process parameters is carried out, as shown in fig. 1 and fig. 2, the steel plate is a typical acicular ferrite structure, the acicular ferrite structure is compact and is interwoven, the dislocation density is large, the structure of the steel plate 1/2 position is uniform and fine, and the crystal grains contain fine carbides, precipitates, M/A islands and the like, and the microstructure not only can ensure the strength of the steel plate, but also can ensure that the steel plate 1/2 position has good toughness.
Example 2
The thickness of the economical steel plate for the large-thickness pipe fitting is 30mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.07%, Si: 0.26%, Mn: 1.60%, P: 0.012%, S: 0.001%, Al: 0.030%, Nb: 0.035%, Ti: 0.010%, Cr: 0.3%, N: 0.0020%, O: 0.0020%, 0.0001% of H, and the balance Fe and inevitable impurities, CEpcm = 0.17%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 18min, maintaining RH vacuum for 13min, and statically blowing argon for 16 min;
2. continuous casting: the superheat degree is 16 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class does not exist;
3. heating: the temperature of the heating soaking section is 1170 ℃, and the total heating time of the casting blank in the heating furnace is 260 min;
4. rolling and cooling: the method comprises the steps of adopting a recrystallization zone and a non-recrystallization zone two-stage controlled rolling process, wherein the initial rolling temperature of rough rolling is 1050 ℃, the cumulative reduction rate is 70%, the final secondary reduction rates are 18%, 18% and 19%, respectively, the initial rolling temperature of finish rolling is 880 ℃, the final rolling temperature is 800 ℃, the cumulative reduction rate is 65%, and after the final secondary rolling is finished, quick steel throwing is adopted to enable a steel plate to quickly enter a controlled cooling zone to avoid grain growth, and the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature for red returning of the steel plate is 590 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 495MPa, the tensile strength is 690MPa, the yield ratio is 0.72, the transverse impact energy is 160J at the position of 1/2 ℃ below zero and 30 ℃, the longitudinal impact energy is 200J at the position of 1/2 ℃ below zero and 30 ℃, and the DWTT is 88 percent at the temperature of-20 ℃; the samples are quenched at 910-; the standard is qualified according to NB/T47013-.
Example 3
The thickness of the economical steel plate for the large-thickness pipe fitting is 40mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.09%, Si: 0.15%, Mn: 1.55%, P: 0.011%, S: 0.002%, Al: 0.030%, Nb: 0.040%, Ti: 0.020%, Cr: 0.2%, N: 0.0020%, O: 0.0010%, 0.0001% of H, and the balance of Fe and inevitable impurities, wherein CEpcm = 0.18%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 20min, maintaining RH vacuum for 15min, and statically blowing argon for 12 min;
2. continuous casting: the superheat degree is 14 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class does not exist;
3. heating: the temperature of the heating soaking section is 1200 ℃, and the total heating time of the casting blank in the heating furnace is 280 min;
4. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1070 ℃, the cumulative reduction rate is 65%, the final reduction rates of the last three passes are respectively 16%, 18% and 20%, the initial rolling temperature of finish rolling is 900 ℃, the final rolling temperature is 810 ℃, the cumulative reduction rate is 58%, and after the final pass is finished, the steel is quickly polished to enable the steel plate to quickly enter a controlled cooling zone to avoid grain growth, the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature for red returning of the steel plate is 570 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 469MPa, the tensile strength is 613MPa, the yield ratio is 0.76, the transverse impact energy at the position of 1/2 ℃ below zero is 170J, the longitudinal impact energy at the position of 1/2 ℃ below zero is 240J, and the DWTT at the temperature of-20 ℃ is 88%; the sample is quenched at 910-; the standard is qualified according to NB/T47013-.
Example 4
The thickness of the economical steel plate for the large-thickness pipe fitting is 40mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.07%, Si: 0.25%, Mn: 1.60%, P: 0.011%, S: 0.001%, Al: 0.030%, Nb: 0.045%, Ti: 0.016%, Cr: 0.25%, N: 0.0030%, O: 0.0010%, 0.0001% of H, and the balance of Fe and inevitable impurities, wherein CEpcm = 0.17%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 17min, maintaining RH vacuum for 12min, and statically blowing argon for 15 min;
2. continuous casting: the superheat degree is 18 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class is 0.5;
3. heating: the temperature of the heating soaking section is 1190 ℃, and the total heating time of the casting blank in the heating furnace is 270 min;
4. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, the initial rolling temperature of rough rolling is 1040 ℃, the cumulative reduction rate is 64%, the final three-pass reduction rate is 18%, 18% and 20% respectively, the initial rolling temperature of finish rolling is 860 ℃, the final rolling temperature is 790 ℃, the cumulative reduction rate is 55%, and after the final pass is finished, the steel is quickly polished, so that the steel plate quickly enters a controlled cooling zone, crystal grains are prevented from growing up, the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature for red returning of the steel plate is 580 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 480MPa, the tensile strength is 630MPa, the yield ratio is 0.76, the transverse impact energy is 175J at the temperature of 1/2-30 ℃ in thickness, the longitudinal impact energy is 235J at the temperature of 1/2-30 ℃ in thickness, and the DWTT is 87% at the temperature of-20 ℃; the sample is quenched at 910-; the standard is qualified according to NB/T47013-.
Example 5
The thickness of the economical steel plate for the large-thickness pipe fitting is 50mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.06%, Si: 0.30%, Mn: 1.58%, P: 0.009%, S: 0.001%, Al: 0.025%, Nb: 0.040%, Ti: 0.025%, Cr: 0.21%, N: 0.0030%, O: 0.0020%, 0.0001% of H, and the balance Fe and inevitable impurities, CEpcm = 0.16%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 19min, maintaining RH vacuum for 13min, and statically blowing argon for 14 min;
2. continuous casting: the superheat degree is 20 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class is 0.5;
3. heating: the temperature of a heating soaking section is 1220 ℃, and the total heating time of the casting blank in the heating furnace is 300 min;
4. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1100 ℃, the cumulative reduction rate is 60%, the final three-pass reduction rates are respectively 18%, 20% and 21%, the initial rolling temperature of finish rolling is 870 ℃, the final rolling temperature is 780 ℃, the cumulative reduction rate is 50%, and after the final pass is finished, the steel is quickly polished, so that the steel plate quickly enters a controlled cooling zone, crystal grains are prevented from growing up, the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature for red returning of the steel plate is 560 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 485MPa, the tensile strength is 650MPa, the yield ratio is 0.75, the transverse impact energy is 165J at the thickness of 1/2 and 30 ℃, the longitudinal impact energy is 215J at the thickness of 1/2 and 30 ℃, and the DWTT is 89 percent at the temperature of minus 20 ℃; the sample is quenched at 910-; the standard is qualified according to NB/T47013-.
Example 6
The thickness of the economical steel plate for the large-thickness pipe fitting is 50mm, and the steel plate comprises the following chemical components in percentage by mass: c: 0.07%, Si: 0.26%, Mn: 1.59%, P: 0.010%, S: 0.002%, Al: 0.030%, Nb: 0.035%, Ti: 0.015%, Cr: 0.22%, N: 0.0020%, O: 0.0010%, 0.00015% of H, the balance being Fe and unavoidable impurities, CEpcm = 0.17%.
The production steps and technological parameters of the steel plate are as follows:
1. smelting: keeping the LF refining white slag for 18min, maintaining RH vacuum for 17min, and statically blowing argon for 13 min;
2. continuous casting: the superheat degree is 10 ℃, the thickness of a casting blank is 250mm, the pulling speed is 0.7m/min, and the center segregation C class does not exist;
3. heating: the temperature of a heating soaking section is 1220 ℃, and the total heating time of the casting blank in the heating furnace is 290 min;
4. rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1080 ℃, the cumulative reduction rate is 62%, the final secondary reduction rates are 18%, 19% and 21% respectively, the initial rolling temperature of finish rolling is 860 ℃, the final rolling temperature is 790 ℃, the cumulative reduction rate is 53%, and after the final secondary rolling is finished, rapid steel throwing is adopted to enable a steel plate to rapidly enter a controlled cooling zone to avoid grain growth, the steel plate is cooled by adopting an ACC controlled cooling mode, and the temperature of red returning of the steel plate is 550 ℃.
The mechanical properties of the steel plate obtained in the embodiment are as follows: the yield strength of the steel plate is 481MPa, the tensile strength is 625MPa, the yield ratio is 0.77, the transverse impact energy is 155J at the thickness of 1/2 and 30 ℃, the longitudinal impact energy is 220J at the thickness of 1/2 and 30 ℃, and the DWTT is 86 percent at the temperature of-20 ℃; the sample is quenched at 910-; the standard is qualified according to NB/T47013-.
Claims (9)
1. The utility model provides an economic large thickness steel sheet for pipe fitting which characterized in that: the paint comprises the following components in percentage by mass: c: 0.06-0.09%, Si: 0.15-0.30%, Mn: 1.55-1.65%, P is less than or equal to 0.012%, S is less than or equal to 0.002%, Al: 0.025 to 0.045%, Nb: 0.035 to 0.045%, Ti: 0.010-0.025%, Cr: 0.20-0.30%, N is less than or equal to 0.0030%, O is less than or equal to 0.0020%, H is less than or equal to 0.00015%, and the balance is Fe and inevitable impurities, wherein CEpcm = C + Si/30+ (Mn + Cu + Cr)/20+ Ni/60+ Mo/15+ V/10+5B is less than or equal to 0.18%.
2. The utility model provides an economic large thickness steel sheet for pipe fitting which characterized in that: the paint comprises the following components in percentage by mass: c: 0.07-0.09%, Si: 0.15-0.25%, Mn: 1.55-1.60%, P is less than or equal to 0.012%, S is less than or equal to 0.002%, Al: 0.025 to 0.030%, Nb: 0.040-0.045%, Ti: 0.016-0.025%, Cr: 0.25 to 0.30 percent of the total weight of the alloy, less than or equal to 0.0030 percent of N, less than or equal to 0.0020 percent of O, less than or equal to 0.00015 percent of H, and the balance of Fe and inevitable impurities, wherein CEpcm is less than or equal to 0.18 percent.
3. The utility model provides an economic large thickness steel sheet for pipe fitting which characterized in that: the paint comprises the following components in percentage by mass: c: 0.07%, Si: 0.25%, Mn: 1.60%, P: 0.011%, S: 0.001%, Al: 0.030%, Nb: 0.045%, Ti: 0.016%, Cr: 0.25%, N: 0.0030%, O: 0.0010%, 0.0001% of H, and the balance of Fe and inevitable impurities, wherein CEpcm = 0.17%.
4. A manufacturing method of an economical steel plate for large-thickness pipe fittings is characterized by comprising the following steps: the method comprises the following steps:
(1) smelting: molten iron pretreatment → converter smelting → LF furnace treatment → RH vacuum treatment → continuous casting;
in the converter smelting, the tapping P is less than or equal to 0.010 percent, the tapping S is less than or equal to 0.003 percent, and an aluminum wire is added in an argon station for deoxidation; in LF refining, the white slag retention time is more than or equal to 17 min; RH vacuum pressure maintaining is carried out, the pressure is less than or equal to 100Pa, the time is more than or equal to 12min, calcium treatment is carried out before tapping, the static argon blowing time is more than or equal to 12min after wire feeding, the content of gas is controlled, and the mass percentage content is as follows: n is less than or equal to 0.0030 percent, O is less than or equal to 0.0020 percent, and H is less than or equal to 0.00015 percent; controlling the superheat degree to be less than or equal to 20 ℃ in the continuous casting process, adopting a secondary cooling electromagnetic stirring and solidification tail end soft pressing mode, keeping a constant drawing speed in the casting process, wherein the drawing speed range is 0.6-0.8 m/min, and the center segregation C class is less than or equal to 1.0;
(2) a heating step: a walking beam type heating furnace is adopted, the temperature of a soaking section is controlled to be 1170-1230 ℃, and the total heating time of the casting blank in the heating furnace is 260-300 min;
(3) rolling and cooling: the method adopts a two-stage controlled rolling process of a recrystallization zone and a non-recrystallization zone, wherein the initial rolling temperature of rough rolling is 1020-.
5. The method for manufacturing an economical steel plate for a large-thickness pipe fitting according to claim 4, wherein: the yield strength of the steel plate is more than or equal to 469MPa, the tensile strength is more than or equal to 613MPa, the yield ratio is less than or equal to 0.77, the transverse impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ below zero is more than or equal to 150J, the longitudinal impact energy at the position with the thickness of 1/2 and at the temperature of 30 ℃ below zero is more than or equal to 200J, and the DWTT at the temperature of 20 ℃ below zero is more than or equal to 85 percent.
6. The method for manufacturing an economical steel plate for a large-thickness pipe fitting according to claim 4, wherein: the quenching temperature of the sample is 910-.
7. The method for manufacturing an economical steel plate for a large-thickness pipe fitting according to claim 6, wherein: the sample quenching is water quenching.
8. The method for manufacturing an economical steel plate for a large-thickness pipe fitting according to claim 4, wherein: the flaw detection result of the steel plate meets the I-level requirement of NB/T47013-.
9. The method for manufacturing an economical steel plate for a large-thickness pipe fitting according to claim 4, wherein: the thickness of the steel plate is 30-50mm, and the thickness of the continuous casting billet/the thickness of the finished steel plate is less than or equal to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210591815.6A CN114892102B (en) | 2022-05-28 | 2022-05-28 | Economical steel plate for large-thickness pipe fitting and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210591815.6A CN114892102B (en) | 2022-05-28 | 2022-05-28 | Economical steel plate for large-thickness pipe fitting and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114892102A true CN114892102A (en) | 2022-08-12 |
| CN114892102B CN114892102B (en) | 2023-08-15 |
Family
ID=82725255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210591815.6A Active CN114892102B (en) | 2022-05-28 | 2022-05-28 | Economical steel plate for large-thickness pipe fitting and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114892102B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112501496A (en) * | 2020-10-20 | 2021-03-16 | 江苏省沙钢钢铁研究院有限公司 | On-line quenching type double-phase low-yield-ratio steel plate and production method thereof |
| WO2022022066A1 (en) * | 2020-08-17 | 2022-02-03 | 莱芜钢铁集团银山型钢有限公司 | Steel board for polar marine engineering and preparation method therefor |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3812168B2 (en) * | 1998-09-30 | 2006-08-23 | 住友金属工業株式会社 | Manufacturing method of seamless steel pipe for line pipe with excellent strength uniformity and toughness |
| CN100547106C (en) * | 2007-12-10 | 2009-10-07 | 巨龙钢管有限公司 | A kind of X80 steel made pipe fittings and manufacturing process thereof |
| CN103014554B (en) * | 2011-09-26 | 2014-12-03 | 宝山钢铁股份有限公司 | Low-yield-ratio high-tenacity steel plate and manufacture method thereof |
| CN106191662A (en) * | 2016-08-25 | 2016-12-07 | 山东钢铁股份有限公司 | A kind of titanium deoxidation easy-weld hardening high-strength tenacity steel plate and manufacture method thereof |
| CN107937802A (en) * | 2017-10-26 | 2018-04-20 | 江阴兴澄特种钢铁有限公司 | 60 80mm thickness low-crackle sensitives, easy weld-end fittings steel plate and its manufacture method used under a kind of cryogenic conditions |
| CN110306111A (en) * | 2019-07-17 | 2019-10-08 | 张家港宏昌钢板有限公司 | A kind of thick steel plates and its manufacturing method |
-
2022
- 2022-05-28 CN CN202210591815.6A patent/CN114892102B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022022066A1 (en) * | 2020-08-17 | 2022-02-03 | 莱芜钢铁集团银山型钢有限公司 | Steel board for polar marine engineering and preparation method therefor |
| CN112501496A (en) * | 2020-10-20 | 2021-03-16 | 江苏省沙钢钢铁研究院有限公司 | On-line quenching type double-phase low-yield-ratio steel plate and production method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114892102B (en) | 2023-08-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109536846B (en) | High-toughness hot-rolled steel plate with yield strength of 700MPa and manufacturing method thereof | |
| CN100548567C (en) | The manufacture method of ultralow temperature high intensity fine grain simple steel flange | |
| CN110983187A (en) | Novel high-strength weather-resistant pipeline steel X80 steel plate and production method thereof | |
| CN113637917A (en) | 690 MPa-level ultrahigh-strength extra-thick ship plate steel with excellent low-temperature impact performance and production method thereof | |
| CN112981254A (en) | Wide high-strength high-toughness thick-wall X80M pipeline steel plate and manufacturing method thereof | |
| CN114645183A (en) | Production method of high-toughness low-yield-ratio low-alloy high-strength steel plate | |
| CN113462972A (en) | Quenching and tempering high-strength low-temperature-resistant H-shaped steel for ocean engineering and preparation method thereof | |
| CN112813346A (en) | Cold heading steel suitable for 6.8 and 8.8-grade weather-resistant fasteners and production method thereof | |
| CN112813344A (en) | High-strength high-toughness easy-to-weld structural steel plate with yield strength of 620MPa and preparation method thereof | |
| CN111926253A (en) | Hydrogen sulfide corrosion resistant high-strength toughness normalized steel and manufacturing method thereof | |
| CN111321354B (en) | X70M hot-rolled steel strip and manufacturing method thereof | |
| CN111793777A (en) | 1000 MPa-level hot-rolled high-strength corrosion-resistant dual-phase steel plate and preparation method thereof | |
| CN114058974B (en) | 15.9-grade corrosion-resistant high-strength bolt steel and production method and heat treatment method thereof | |
| CN111455267A (en) | High-strength and high-toughness J55 hot rolled steel strip and production method thereof | |
| CN111876696B (en) | Steel plate for X100 pipe fitting with service temperature below-60 ℃ and manufacturing method thereof | |
| CN114752863B (en) | Steel plate for thin TMCP+ tempered pipe fitting and manufacturing method thereof | |
| CN115161545B (en) | High-plasticity low-strength medium-carbon cold heading steel precision wire and production method thereof | |
| CN116426842A (en) | Steel for Nb-Ti component L360M-WG hot-bending bend and production method thereof | |
| CN114892102A (en) | Economical steel plate for large-thickness pipe fitting and manufacturing method thereof | |
| CN114774779A (en) | Hot-rolled round steel for Christmas tree valve in oil field in alpine region and preparation method thereof | |
| CN113699462A (en) | Hot-rolled steel strip for 750 MPa-grade continuous oil pipe and manufacturing method thereof | |
| CN110331332A (en) | It is a kind of to produce the super thick pipe part steel plate used under condition of ultralow temperature and its manufacturing method with DQ substitution hardening and tempering process | |
| CN115369327B (en) | Rare earth microalloying low-temperature structural pipe and manufacturing method thereof | |
| CN112853205B (en) | 850 MPa-grade low-yield-ratio hot-rolled high-strength complex phase steel and manufacturing method thereof | |
| CN115261727B (en) | MnV-series non-quenched and tempered cold heading steel wire rod for 9.8-grade fastener and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |