EP4129510A1 - Hochfestes stahlblech für säureresistentes leitungsrohr, verfahren zur herstellung davon und mit hochfestem stahlblech hergestelltes leitungsrohr für säureresistentes stahlrohr - Google Patents

Hochfestes stahlblech für säureresistentes leitungsrohr, verfahren zur herstellung davon und mit hochfestem stahlblech hergestelltes leitungsrohr für säureresistentes stahlrohr Download PDF

Info

Publication number
EP4129510A1
EP4129510A1 EP21774925.8A EP21774925A EP4129510A1 EP 4129510 A1 EP4129510 A1 EP 4129510A1 EP 21774925 A EP21774925 A EP 21774925A EP 4129510 A1 EP4129510 A1 EP 4129510A1
Authority
EP
European Patent Office
Prior art keywords
steel plate
less
temperature
sour
strength steel
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.)
Pending
Application number
EP21774925.8A
Other languages
English (en)
French (fr)
Inventor
Daichi Izumi
Junji Shimamura
Yuta TAMURA
Satoshi Ueoka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
JFE Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by JFE Steel Corp filed Critical JFE Steel Corp
Publication of EP4129510A1 publication Critical patent/EP4129510A1/de
Pending legal-status Critical Current

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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
    • 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
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • 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
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • 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
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • 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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes

Definitions

  • This disclosure relates to a high strength steel plate for a sour-resistant line pipe that is excellent in material homogeneity in the steel plate and that is suitable for use in line pipes in the fields of construction, marine structure, shipbuilding, civil engineering, and construction industry machinery, and to a method for manufacturing the same.
  • This disclosure also relates to a high strength steel pipe using the high strength steel plate for a sour-resistant line pipe.
  • a line pipe is typically manufactured by forming a steel plate manufactured by a plate mill or a hot rolling mill into a steel pipe by UOE forming, press bend forming, roll forming, or the like.
  • the line pipe used to transport crude oil and natural gas containing hydrogen sulfide is required to have so-called sour resistance such as resistance to hydrogen-induced cracking (HIC resistance) and resistance to sulfide stress corrosion cracking (SSCC resistance), in addition to strength, toughness, weldability, and so on.
  • HIC is the following phenomenon: Hydrogen ions due to corrosion reaction adsorb to the surface of steel material and enter into the steel as atomic hydrogen, diffuse and accumulate around nonmetallic inclusions such as MnS and hard secondary phase in the steel, and become molecular hydrogen, the internal pressure of which causes cracking. This phenomenon is considered as a problem in line pipes with a relatively low level of strength with respect to oil well pipes, and many countermeasures have been proposed.
  • SSCC is known to occur in high hardness regions of welds, and in general has not been regarded as a significant problem in high strength seamless steel pipes for oil wells and line pipes with relatively low hardness.
  • mining environments for crude oil and natural gas have become increasingly severe, and it has been reported that SSCC also occurs in the base metal of line pipes in environments with high hydrogen sulfide partial pressure or low pH. This has raised the importance of controlling the hardness of the surface layer of the inner surface of a steel pipe to improve the SSCC resistance under more severe corrosion environments.
  • microcracking called fissure may occur in environments with relatively low hydrogen sulfide partial pressure and SSCC is likely to occur in this case, too.
  • TMCP Thermo-Mechanical Control Process
  • TMCP Thermo-Mechanical Control Process
  • An effective way of enhancing the strength of steel plates using the TMCP technology is to increase the cooling rate in controlled cooling.
  • the control cooling is performed at a high cooling rate, the surface layer of the steel plate is rapidly cooled, and the hardness of the surface layer becomes higher than that of the inside of the steel plate.
  • work hardening occurs when steel plates are formed into pipes, and hence the hardness of the surface layer increases and the SSCC resistance decreases.
  • JP3951428B (PTL 1) and JP3951429B (PTL 2) describe methods for performing high-speed controlled cooling in which the surface is recuperated before completion of bainite transformation in the surface layer after rolling.
  • JP2002-327212A (PTL 3) and JP3711896B (PTL 4) describe methods for manufacturing steel plates for line pipes in which the hardness of the surface layer is reduced by heating the surface of a steel plate after accelerated cooling to a higher temperature than the inside using a high frequency induction heating device.
  • JPH9-57327A (PTL 5) and JP3796133B (PTL 6) describe methods for improving the shape of a steel plate by performing descaling immediately before cooling the steel plate to reduce cooling unevenness caused by scale thickness unevenness.
  • the methods of PTLs 5 and 6 apply descaling to reduce the surface characteristics defects due to the scale indentation during hot leveling and to reduce the variation in the cooling stop temperature of the steel plate to improve the steel plate shape.
  • no optimization has been made concerning the descaling conditions from the viewpoint of improving SSCC resistance.
  • no consideration has been given to the cooling conditions to reduce the hardness of surface layers of steel plates.
  • the present inventors have studied the above issues and found that simply reducing the hardness of the surface layer, as conventionally known, is not sufficient to further improve the SSCC resistance of high strength steel pipes.
  • a locally high hardness portion is formed in the outermost part of the surface layer, which is infinitely close to a surface of the steel plate, and SSCC occurs starting from this region.
  • the inventors discovered that the adoption of a certain composition and the formation of magnetite-based scale on a surface of a steel plate were necessary conditions for obtaining a high strength steel plate without any local high hardness portions at 0.25 mm below the surface of the steel plate. It was revealed that in order to form magnetite-based scale on a surface of a steel plate, it is necessary to optimize the descaling conditions during the hot rolling process and to set the cooling stop temperature during controlled cooling within a predetermined range. The inventors also discovered that as one of the necessary conditions for manufacture, it is important to strictly control the cooling rate at 0.25 mm below the surface of the steel plate, and succeeded in finding the conditions to be met. The present disclosure was completed based on the above discoveries.
  • the high strength steel plate for a sour-resistant line pipe and the high strength steel pipe using the high strength steel plate for a sour-resistant line pipe disclosed herein are excellent not only in HIC resistance but also in SSCC resistance under more severe corrosion environments and environments with low hydrogen sulfide partial pressure below 1 bar.
  • FIG. 1 is a schematic view illustrating a method for obtaining test pieces for evaluation of SSCC resistance in Examples.
  • the C content effectively contributes to the improvement in strength.
  • the content is less than 0.020 %, sufficient strength cannot be secured. Therefore, the C content is 0.020 % or more, and preferably 0.025 % or more.
  • the C content exceeds 0.080 %, the hardness of the surface layer and the central segregation area increases during accelerated cooling, causing deterioration in SSCC resistance and HIC resistance. The toughness also deteriorates. Therefore, the C content is 0.080 % or less, and preferably 0.070 % or less.
  • Si is added for deoxidation. However, if the content is less than 0.01 %, the deoxidizing effect is not sufficient. Therefore, the Si content is 0.01 % or more, and preferably 0.05 % or more. On the other hand, if the Si content exceeds 0.50 %, the toughness and weldability are degraded. Therefore, the Si content is 0.50 % or less, and preferably 0.45 % or less.
  • the Mn effectively contributes to the improvement in strength and toughness. However, if the content is less than 0.50 %, the addition effect is not sufficient. Therefore, the Mn content is 0.50 % or more, and preferably 0.80 % or more. On the other hand, if the Mn content exceeds 1.80 %, the hardness of the surface layer and the central segregation area increases during accelerated cooling, causing deterioration in SSCC resistance and HIC resistance. The weldability also deteriorates. Therefore, the Mn content is 1.80 % or less, and preferably 1.70 % or less.
  • the P content is an inevitable impurity element that degrades the weldability and increases the hardness of the surface layer and the central segregation area, causing deterioration in SSCC resistance and HIC resistance. This tendency becomes more pronounced when the P content exceeds 0.015 %. Therefore, the P content is 0.015 % or less, and preferably 0.008 % or less. Although a lower P content is preferable, the P content is preferably 0.001 % or more from the viewpoint of the refining cost.
  • the S content is 0.0015 % or less, and preferably 0.0010 % or less. Although a lower S content is preferable, the S content is preferably 0.0002 % or more from the viewpoint of the refining cost.
  • Al is added as a deoxidizing agent. However, if the content is less than 0.010 %, the addition effect is not sufficient. Therefore, the Al content is 0.010 % or more, and preferably 0.015 % or more. On the other hand, an Al content beyond 0.080 % lowers the cleanliness of the steel and deteriorates the toughness. Therefore, the Al content is 0.080 % or less, and preferably 0.070 % or less.
  • N effectively contributes to the improvement in strength. However, if the content is less than 0.0010 %, sufficient strength cannot be secured. Therefore, the N content is 0.0010 % or more, and preferably 0.0015 % or more. On the other hand, if the N content exceeds 0.0080 %, the hardness of the surface layer and the central segregation area increases during accelerated cooling, causing deterioration in SSCC resistance and HIC resistance. The toughness also deteriorates. Therefore, the N content is 0.0080 % or less, and preferably 0.0070 % or less.
  • Mo is an effective element for improving toughness and increasing strength, it is an effective element for improving SSCC resistance regardless of the hydrogen sulfide partial pressure.
  • the inventors found that after subjection to the SSCC test, steel plates containing Mo had surfaces smoother than those of other steel plates without containing Mo. Although the mechanism is not necessarily clear, this fact may be related to the improved SSCC resistance.
  • the Mo content needs to be 0.01 % or more, and is preferably 0.10 % or more.
  • the Mo content exceeds 0.50 %, the hardenability becomes excessively high, causing an increase in the hardness of the surface layer and the central segregation area during accelerated cooling and deteriorating the SSCC resistance and HIC resistance. The weldability also deteriorates. Therefore, the Mo content is 0.50 % or less, and preferably 0.40 % or less.
  • Ca is an element effective for improving the HIC resistance by morphological control of sulfide inclusions.
  • the Ca content is 0.0005 % or more, and preferably 0.0008 % or more.
  • the Ca content is 0.0050 % or less, and preferably 0.0045 % or less.
  • the chemical composition according to the present disclosure may also contain at least one selected from the group consisting of Cu, Ni, and Cr in the following ranges to further improve the strength and toughness of the steel plate.
  • the Cu is an element effective for improving the toughness and increasing the strength. To obtain this effect, the Cu content is preferably 0.05 % or more. However, if the Cu content exceeds 0.30 %, SSCC resistance deteriorates because microcracks called fissures easily form in environments with low hydrogen sulfide partial pressures below 1 bar. Therefore, when Cu is added, the Cu content is 0.30 % or less, and preferably 0.25 % or less.
  • Ni is an element effective for improving the toughness and increasing the strength. To obtain this effect, the Ni content is preferably 0.01 % or more. However, if the Ni content exceeds 0.10 %, SSCC resistance deteriorates because microcracks called fissures easily form in environments with low hydrogen sulfide partial pressures below 1 bar. Therefore, when Ni is added, the Ni content is 0.10 % or less, and preferably 0.05 % or less.
  • the Cr content is preferably 0.05 % or more.
  • the Cr content exceeds 0.50 %, the hardenability becomes excessively high, causing an increase in the hardness of the surface layer and the central segregation area during accelerated cooling and deteriorating the SSCC resistance and HIC resistance. The weldability also deteriorates. Therefore, when Cr is added, the Cr content is 0.50 % or less, and preferably 0.45 % or less.
  • the chemical composition according to the present disclosure may further contain at least one selected from the group consisting of Nb, V, Ti, Zr, Mg, and REM in the following ranges.
  • Nb, V, and Ti are elements that can be optionally added to increase the strength and toughness of the steel plate. If the content of each added element is less than 0.005 %, the addition effect is not sufficient. Therefore, the content of each added element is preferably 0.005 % or more. On the other hand, if the content of each added element exceeds 0.1 %, the toughness of the welded portion deteriorates. Therefore, the content of each added element is preferably 0.1 % or less.
  • Zr, Mg, and REM are elements that can be optionally added in order to enhance the toughness through grain refinement and to improve the cracking resistance through control of the inclusion properties. If the content of each added element is less than 0.0005 %, the addition effect is not sufficient. Therefore, the content of each added element is preferably 0.0005 % or more. On the other hand, if the content of each added element exceeds 0.02 %, the addition effect is saturated. Therefore, when added, the content of each added element is preferably 0.02 % or less.
  • the present disclosure relates to a technique for improving the SSCC resistance of the high strength steel pipe using the high strength steel plate for a sour-resistant line pipe
  • the technique disclosed herein needs to satisfy the HIC resistance at the same time as the sour resistant performance.
  • the CP value obtained by the following Expression (1) is preferably set to 1.00 or less.
  • CP 4.46 % C + 2.37 % Mn / 6 + 1.74 % Cu + 1.7 % Ni / 15 + 1.18 % Cr + 1.95 % Mo + 1.74 % V ) / 5 + 22.36 % P
  • [%X] represents the content by mass% of the element X in steel.
  • the CP value is a formula designed to estimate the material property at the central segregation area from the content of each alloying element.
  • the CP value calculated according to Formula (1) is higher, the component concentration in the central segregation area is higher, and the hardness of the central segregation area increases.
  • the CP value obtained in Expression (1) is 1.00 or less, it is possible to suppress the occurrence of cracking in the HIC test.
  • the upper limit for the CP value may be set to 0.95 when higher HIC resistance is required.
  • the balance other than the above-described elements is Fe and inevitable impurities.
  • O is an element that is inevitably contained in the steel, and a content of 0.0050 % or less, preferably 0.0040 % or less, is allowable in the present disclosure.
  • the steel microstructure of the high strength steel plate for a sour-resistant line pipe disclosed herein will be described.
  • the surface layer is preferably formed with bainite phase as the steel microstructure.
  • the steel microstructure at 0.25 mm below the surface of the steel plate be bainite phase.
  • the entire steel microstructure of the steel plate, including portions other than the surface layer be bainite phase. Specifically, it suffices for the microstructure at the mid-thickness position representative of the "portions other than the surface layer" to be bainite phase.
  • the bainite phase includes a microstructure called bainitic ferrite or granular ferrite which contributes to transformation strengthening. These microstructures appear through transformation during or after accelerated cooling. If different microstructures such as ferrite, martensite, pearlite, martensite austenite constituent, retained austenite, and the like are mixed in the bainite phase, the strength decreases, the toughness is degraded, and the hardness of the surface layer increases. Therefore, the proportion of microstructures other than the bainite phase is desirably as low as possible. However, when the area fraction of such microstructures other than the bainitic phase is sufficiently low, their effects are negligible.
  • the inclusion of up to a certain amount of microstructure other than bainitic phase is allowable.
  • the total of the steel microstructures other than bainite (such as ferrite, martensite, pearlite, martensite austenite constituent, and retained austenite) is less than 10 % by area fraction, there is no adverse effect, and this is acceptable. More preferably, the total of the steel microstructures other than bainite is less than 5 % by area fraction.
  • a magnetite proportion in scale present on a surface of the steel plate after controlled cooling be 50 % or more.
  • scale present on a surface of the steel plate after controlled cooling is composed of wustite (FeO), magnetite (Fe 3 O 4 ), and hematite (Fe 2 O 3 ).
  • FeO wustite
  • Fe 3 O 4 magnetite
  • Fe 2 O 3 hematite
  • the magnetite proportion in order to keep the highest Vickers hardness at 0.25 mm below the surface of the steel plate as low as 230 HV or less, the magnetite proportion needs to be 50 % or more.
  • the upper limit of the magnetite proportion is not particularly limited, and the magnetite proportion may be 100 % or less or 95 % or less.
  • the highest Vickers hardness (HV 0.5) at 0.25 mm below the surface of the steel plate be 230 HV or less. These conditions can provide excellent SSCC resistance even in more severe corrosion environments and at low hydrogen sulfide partial pressures below 1 bar. If the highest Vickers hardness at 0.25 mm below the surface of the steel plate is greater than 230 HV, the presence of a local high hardness portion in the outermost surface layer causes deterioration in the resistance to SSCC originating from that portion.
  • the highest Vickers hardness (HV 0.5) at 0.25 mm below the surface of the steel plate means the highest value of 100 measurements taken at equal intervals along the plate width direction in a cross section perpendicular to the rolling direction of the steel plate.
  • HV 0.5 the indentation size can be made smaller when measuring with HV 0.5, making it possible to obtain hardness information closer to the surface and hardness information more sensitive to the microstructures. Measuring with at less than HV 0.5 results in excessively small indentation size and large measurement variation.
  • the reason for using the highest hardness instead of the average hardness is as follows. That is, the evaluation based on the highest hardness, rather than the average hardness, can detect local hard portions, and is more suitable for accurately examining crack propagation susceptibility since the presence of local hard portions makes crack propagation easier.
  • the high strength steel plate disclosed herein is a steel plate for steel pipes having a strength of X60 grade or higher in API 5L, and thus has a tensile strength of 520 MPa or more.
  • the high strength steel plate disclosed herein has a thickness of 14 mm to 39 mm.
  • the manufacturing method according to the present disclosure comprises: heating a slab having the above-described chemical composition, and hot rolling the slab to form a steel plate; and then subjecting the steel plate to controlled cooling under predetermined conditions.
  • the slab heating temperature is 1000 °C or higher, and preferably 1030 °C or higher.
  • the slab heating temperature is 1300 °C or lower, and preferably 1250 °C or lower. This temperature is the temperature in the heating furnace, and the slab is heated to this temperature to the center.
  • the steel plate in the hot rolling process, it is important to subject the steel plate to descaling at a discharge pressure of 10 MPa or more in a number of rolling passes as many as 50 % or more of a total number of rolling passes during the hot rolling.
  • rolling passes is intended to include both rolling passes for rough rolling and rolling passes for finish rolling during the hot rolling process.
  • a surface of a slab is descaled at a discharge pressure of 10 MPa or more at the position immediately before the slab is introduced into those rolling passes.
  • This descaling condition is one of the necessary conditions to suppress the non-uniformity of formation of scale, and to achieve a magnetite proportion of 50 % or more in the scale present on the surface of the steel plate after controlled cooling.
  • the "position immediately before the slab is introduced into those rolling passes" means a position in the longitudinal direction of the hot rolling line within 3 m, preferably within 1.5 m, of the position of the roll shaft of the rolling mill corresponding to the rolling pass.
  • Any number of passes for rough rolling may be applied within a general range without limitation, yet is preferably, for example, 2 or more and 12 or less.
  • Any number of passes for finish rolling may also be applied within a general range without limitation, yet is preferably, for example, 5 or more and 15 or less.
  • Descaling may be performed according to conventional methods, for example, by spraying highpressure water onto the slab surface from a number of descaling nozzles installed along the width direction of the hot-rolling line.
  • general conditions may be adopted for conditions other than the discharge pressure (e.g., water quantity, distance between nozzle and slab, and nozzle angle).
  • the discharge pressure is 10 MPa or more, and preferably 15 MPa or more. A higher discharge pressure is desirable, yet it requires a larger apparatus, and so on. Thus, it is preferable to keep the discharge pressure at or below 25 MPa.
  • the number of descaling is 50 % or more, preferably 60 % or more, of the total number of rolling passes.
  • the upper limit of the number of descaling is not limited, and the number of descaling may be 100 % of the total number of rolling passes, i.e., descaling may be performed immediately before all rolling passes.
  • the rolling finish temperature in terms of a temperature of the surface of the steel plate needs to be set in consideration of the required toughness for base metal and rolling efficiency. From the viewpoint of improving the strength and the HIC resistance, it is preferable to set the rolling finish temperature at or above the Ar 3 transformation temperature in terms of a temperature of the surface of the steel plate.
  • the Ar 3 transformation temperature means the ferrite transformation start temperature during cooling, and can be determined, for example, from the chemical composition of steel according to the following equation. The temperature of the surface of the steel plate can be measured by a radiation thermometer or the like.
  • Ar 3 ° C 910 ⁇ 310 % C ⁇ 80 % Mn ⁇ 20 % Cu ⁇ 15 % Cr ⁇ 55 % Ni ⁇ 80 % Mo , where [%X] indicates the content by mass% of the element X in steel.
  • Cooling start temperature is (Ar 3 - 10 °C) or higher in terms of a temperature of the surface of the steel plate.
  • the temperature of the surface of the steel plate at the start of cooling is low, the amount of ferrite formation before controlled cooling increases.
  • the temperature of the surface of the steel plate at the start of cooling is set to (Ar 3 - 10 °C) or higher. Note that the temperature of the surface of the steel plate at the start of cooling is not higher than the rolling finish temperature.
  • the average cooling rate is set to 100 °C/s or lower, and preferably 80 °C/s or lower. If the average cooling rate is less than 20 °C/s, ferrite and pearlite are formed, resulting in insufficient strength. Therefore, the average cooling rate is set to 20 °C/s or higher.
  • the average cooling rate in a temperature range from 550 °C to the cooling stop cooling temperature in terms of a temperature at 0.25 mm below the surface of the steel plate be 110 °C/s or higher, preferably 150 °C/s or higher. From the viewpoint of more reliably suppressing the formation of high hardness portions, the average cooling rate is preferably set to 200 °C/s or lower.
  • the average cooling rate in terms of an average temperature of the steel plate is set to 15 °C/s or higher.
  • the average cooling rage in terms of an average temperature of the steel plate is preferably 20 °C/s or higher.
  • the upper limit of the average cooling rate is not particularly limited. However, the average cooling rate is preferably 80 °C/s or lower such that excessive low-temperature transformation products will not be generated.
  • a temperature distribution in a cross section in the plate thickness direction can be determined in real time by difference calculation using a process computer, for example, on the basis of the surface temperature at the start of cooling measured by a radiation thermometer and the target surface temperature at the end of cooling.
  • the temperature at 0.25 mm below the surface of the steel plate in the temperature distribution is referred to as the "temperature at 0.25 mm below the surface of the steel plate", and the average value of temperatures in the thickness direction in the temperature distribution as the "average temperature of the steel plate”.
  • Cooling stop temperature 250 °C to 550 °C in terms of a temperature at 0.25 mm below the surface of the steel plate
  • the cooling stop temperature is one of the necessary conditions for achieving a magnetite proportion in scale present on the surface of the steel plate of 50 % or more after controlled cooling.
  • the cooling stop temperature exceeds 550 °C, bainite transformation is incomplete and sufficient strength cannot be obtained.
  • the cooling stop temperature is lower than 250 °C, the magnetite proportion cannot be increased to 50 % or more as a result of increased wustite.
  • the highest Vickers hardness at 0.25 mm below the surface of steel plate exceeds 230 HV, causing deterioration in the SSCC resistance after pipe making.
  • the hardness of the central segregation area increases and the HIC resistance deteriorates. Therefore, the cooling stop temperature is set to 250 °C to 550 °C in terms of a temperature at 0.25 mm below the surface of the steel plate.
  • a high strength steel pipe for sour-resistant line pipes (such as a UOE steel pipe, an electric-resistance welded steel pipe, and a spiral steel pipe) that is suitable for transporting crude oil and natural gas can be manufactured.
  • an UOE steel pipe is manufactured by groove machining the ends of a steel plate, forming the steel plate into a steel pipe shape by C press, U-ing press, and O-ing press, then seam welding the butting portions by inner surface welding and outer surface welding, and optionally subjecting it to an expansion process.
  • Any welding method may be applied as long as sufficient joint strength and joint toughness are guaranteed, yet it is preferable to use submerged arc welding from the viewpoint of excellent weld quality and manufacturing efficiency.
  • Expansion process can also be performed on a steel pipe that has been formed into a pipe shape by press-bend forming and then seam-welded at the butting faces.
  • the steels having the chemical compositions listed in Table 1 were made into slabs by continuous casting, heated to the temperatures listed in Table 2, and then hot rolled at the rolling finish temperatures listed in Table 2 to obtain the steel plates of the thicknesses listed in Table 2.
  • the hot rolling process included a total of 10 to 25 passes, ranging from 2 to 12 passes for rough rolling and 5 to 15 passes for finish rolling, and descaling was performed at the discharge pressures listed in Table 2, in the percentages of the total rolling passes listed in Table 2. Then, each steel plate was subjected to controlled cooling using a water-cooling type controlled-cooling device under the conditions listed in Table 2.
  • each obtained steel plate was observed by an optical microscope and a scanning electron microscope.
  • a sample for observation of metallic microstructure was taken from the central part in the width direction of each steel plate.
  • a cross section parallel to the longitudinal direction of rolling was mirror polished and then subjected to nital etching.
  • the polished surface of each sample was imaged at five locations that were randomly selected at magnifications ranging from 400 to 1000 times, and the area fraction of each phase was calculated by image analysis processing.
  • the microstructures at 0.25 mm below the surface of each steel plate, the type of microstructures at the mid-thickness position, and the area fractions of phases other than the bainite phase are listed in Table 3.
  • Scale was collected from the surface of each obtained steel plate. For scale sampling, samples were taken at a total of nine locations, i.e., at the central part and both ends in the width direction of the steel plate at the leading end, center, and trailing end of the steel plate in the longitudinal direction, respectively. At each location, at least 0.5 g of scale was collected. Then, on the scale collected at each location, phase identification was performed by X-ray diffraction (XRD) and quantitative analysis (i.e., measurement of magnetite proportion) was performed using a reference intensity ratio (RIR). The result of averaging the magnetite proportion of the scale at nine locations is presented in Table 3 as the "Magnetite proportion " according to the present disclosure.
  • XRD X-ray diffraction
  • RIR reference intensity ratio
  • the SSCC resistance was evaluated for a pipe made from a part of each steel plate.
  • Each pipe was manufactured by groove machining the ends of a steel plate, and forming the steel plate into a steel pipe shape by C press, U-ing press, and O-ing press, then seam welding the butting portions on the inner and outer surfaces by submerged arc welding, and subjecting it to an expansion process.
  • FIG. 1 after a coupon cut out from each obtained steel pipe was flattened, an SSCC test piece of 5 mm ⁇ 15 mm ⁇ 115 mm was collected from the inner surface of the steel pipe. At this time, in addition to specimens of only the base metal without the weld, specimens containing both the weld and base metal were taken.
  • Each collected SSCC test piece was loaded with 90 % stress of the actual yield strength (0.5 % YS) of the corresponding steel pipe, and evaluation was made using a NACE standard TM0177 Solution A solution, at a hydrogen sulfide partial pressure of 1 bar, in accordance with the 4-point bending SSCC test specified by the EFC 16 standard.
  • evaluation was made using a NACE standard TM0177 Solution B solution in accordance with the 4-point bending SSCC test specified by the EFC 16 standard.
  • HIC resistance was examined by performing HIC test at a hydrogen sulfide partial pressure of 1 bar and with an immersion time of 96 hours using a NACE standard TM0177 Solution A solution.
  • HIC resistance was evaluated by performing HIC test at a hydrogen sulfide partial pressure of 0.1 bar and a carbon-dioxide partial pressure of 0.9 bar and with an immersion time of 96 hours using a NACE standard TM0177 Solution B solution.
  • the HIC resistance was judged as "excellent” when the crack length ratio (CLR) was 10 % or less in the HIC test, "good” when the CLR was more than 10 % and 15 % or less, or “poor” when the CLR exceeded 15 %.
  • CLR crack length ratio
  • Nos. 1 to 6 and Nos. 30 to 31 are our examples in which the chemical compositions and the production conditions satisfy the appropriate ranges of the present disclosure.
  • the tensile strength of the steel plate was 520 MPa or more, and the SSCC resistance and HIC resistance were good or excellent.
  • Nos. 7 to 18 are comparative examples whose chemical compositions are outside the scope of the present disclosure.
  • solid solution strengthening was insufficient and the strength was low.
  • the steel plate did not contain Mo, and the SSCC resistance deteriorated under a very severe corrosion environment with a hydrogen sulfide partial pressure of 2 bar.
  • the steel plate had an excessively high Cu content, and the SSCC resistance deteriorated in an environment with a low hydrogen sulfide partial pressure.
  • No. 17 the steel plate had an excessively high Ni content, and the SSCC resistance deteriorated in an environment with a low hydrogen sulfide partial pressure.
  • Nos. 19 to 29 are comparative examples whose chemical compositions are within the scope of the present disclosure but whose manufacturing conditions are outside the scope of the present disclosure.
  • the slab heating temperature was low, the homogenization of the microstructure and the dissolving of carbides were insufficient and the strength was low.
  • the discharge pressure of descaling was less than 10 MPa, scaling was uneven, the magnetite proportion was less than 50 %, and the maximum hardness with HV 0.5 exceeded 230, resulting in inferior SSCC resistance and HIC resistance.
  • Nos. 19 to 29 are comparative examples whose chemical compositions are within the scope of the present disclosure but whose manufacturing conditions are outside the scope of the present disclosure.
  • the discharge pressure of descaling was less than 10 MPa, scaling was uneven, the magnetite proportion was less than 50 %, and the maximum hardness with HV 0.5 exceeded 230, resulting in inferior SSCC resistance and HIC resistance.
  • the magnetite proportion was less than 50 % since the proportion of the number of descaling relative to the number of total rolling passes was less than 50 %, and the highest hardness with HV 0.5 exceeded 230, resulting in inferior SSCC resistance and HIC resistance.
  • the cooling start temperature was low and the microstructure was formed in a layered manner with precipitation of ferrite, the strength was low and the HIC resistance was inferior.
  • the controlled cooling conditions were outside the scope of the present disclosure and a ferrite + bainite microstructure was obtained, the strength was low and the HIC resistance deteriorated. In No.
  • the average cooling rate in a temperature range from 750 °C to 550 °C at 0.25 mm below the surface of the steel plate exceeded 100 °C/s, which resulted in a high proportion of low-temperature transformation phase, and the highest hardness with HV 0.5 at 0.25 mm below the surface of the steel plate exceeded 230, resulting in inferior SSCC resistance.
  • the cooling stop temperature was low, the magnetite proportion was less than 50 %, and the highest hardness with HV 0.5 exceeded 230, resulting in inferior SSCC resistance.
  • the cooling stop temperature was high and bainitic transformation was incomplete, resulting in insufficient strength. Note that the cooling stop temperature was 560 °C in No. 26, and the column "Cooling rate in temp.
  • steel pipes such as electric-resistance welded steel pipes, spiral steel pipes, and UOE steel pipes
  • steel pipes manufactured by cold-forming the disclosed steel plate can be suitably used for transportation of crude oil and natural gas that contain hydrogen sulfides where sour resistance is required.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
EP21774925.8A 2020-03-26 2021-03-18 Hochfestes stahlblech für säureresistentes leitungsrohr, verfahren zur herstellung davon und mit hochfestem stahlblech hergestelltes leitungsrohr für säureresistentes stahlrohr Pending EP4129510A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020056573 2020-03-26
PCT/JP2021/011238 WO2021193383A1 (ja) 2020-03-26 2021-03-18 耐サワーラインパイプ用高強度鋼板およびその製造方法並びに耐サワーラインパイプ用高強度鋼板を用いた高強度鋼管

Publications (1)

Publication Number Publication Date
EP4129510A1 true EP4129510A1 (de) 2023-02-08

Family

ID=77891750

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21774925.8A Pending EP4129510A1 (de) 2020-03-26 2021-03-18 Hochfestes stahlblech für säureresistentes leitungsrohr, verfahren zur herstellung davon und mit hochfestem stahlblech hergestelltes leitungsrohr für säureresistentes stahlrohr

Country Status (6)

Country Link
EP (1) EP4129510A1 (de)
JP (1) JP7264269B2 (de)
KR (1) KR20220137970A (de)
CN (1) CN115298340B (de)
BR (1) BR112022019204A2 (de)
WO (1) WO2021193383A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023233734A1 (ja) * 2022-06-03 2023-12-07 Ｊｆｅスチール株式会社 サワーガス設備用高強度鋼板及びそれを用いた高強度鋼管
JP7332078B1 (ja) 2022-06-03 2023-08-23 Ｊｆｅスチール株式会社 サワーガス設備用高強度鋼板及びそれを用いた高強度鋼管

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62238378A (ja) * 1986-04-08 1987-10-19 Kobe Steel Ltd 耐水素誘起割れ性の優れた表面処理鋼材
JPH0957327A (ja) 1995-08-22 1997-03-04 Sumitomo Metal Ind Ltd 厚鋼板のスケール除去方法
JP3951428B2 (ja) 1998-03-30 2007-08-01 Ｊｆｅスチール株式会社 板厚方向材質差の小さい高張力鋼板の製造方法
JP3951429B2 (ja) 1998-03-30 2007-08-01 Ｊｆｅスチール株式会社 板厚方向材質差の小さい高張力鋼板の製造方法
JP3796133B2 (ja) 2000-04-18 2006-07-12 新日本製鐵株式会社 厚鋼板冷却方法およびその装置
JP2002327212A (ja) 2001-02-28 2002-11-15 Nkk Corp 耐サワーラインパイプ用鋼板の製造方法
JP3711896B2 (ja) 2001-06-26 2005-11-02 Ｊｆｅスチール株式会社 高強度ラインパイプ用鋼板の製造方法
JP4710423B2 (ja) * 2005-06-08 2011-06-29 Ｊｆｅスチール株式会社 耐ｓｓｃ特性に優れた高張力鋼板の製造方法
EP2264206B1 (de) * 2008-04-10 2014-11-26 Nippon Steel & Sumitomo Metal Corporation Hochfeste stahlbleche mit hervorragender balance zwischen abgratverarbeitbarkeit und leitfähigkeit sowie hervorragender ermüdungsfestigkeit, zinkbeschichtete stahlbleche und verfahren zur herstellung von beiden
KR101304859B1 (ko) * 2009-12-04 2013-09-05 주식회사 포스코 표면균열 저항성이 우수한 초고강도 라인파이프용 강판 및 그 제조방법
JP5652110B2 (ja) * 2010-10-18 2015-01-14 Ｊｆｅスチール株式会社 レーザー切断性に優れた鋼板およびその製造方法
CN104024461B (zh) 2012-03-30 2016-04-06 新日铁住金株式会社 抗氢诱发裂纹性优良的高强度管道用钢管和其所使用的高强度管道用钢板、以及它们的制造方法
JP6101132B2 (ja) * 2012-04-20 2017-03-22 株式会社神戸製鋼所 耐水素誘起割れ性に優れた鋼材の製造方法
CN106544587A (zh) * 2016-10-26 2017-03-29 首钢总公司 连铸坯大壁厚深海管线用热轧钢板及其生产方法
JP6665822B2 (ja) * 2017-03-30 2020-03-13 Ｊｆｅスチール株式会社 耐サワーラインパイプ用高強度鋼板およびその製造方法並びに耐サワーラインパイプ用高強度鋼板を用いた高強度鋼管
CN107326261A (zh) * 2017-06-16 2017-11-07 武汉钢铁有限公司 低屈强比薄规格高强抗酸管线钢热轧卷板及其制造方法
JP6866855B2 (ja) 2018-01-29 2021-04-28 Ｊｆｅスチール株式会社 耐サワーラインパイプ用高強度鋼板の製造方法、及び耐サワーラインパイプ用高強度鋼板、並びに耐サワーラインパイプ用高強度鋼板を用いた高強度鋼管
JP6460297B1 (ja) 2018-06-29 2019-01-30 新日鐵住金株式会社 鋼管及び鋼板
JP7155702B2 (ja) 2018-07-19 2022-10-19 日本製鉄株式会社 耐サワーラインパイプ用厚鋼板およびその製造方法

Also Published As

Publication number Publication date
JPWO2021193383A1 (de) 2021-09-30
WO2021193383A1 (ja) 2021-09-30
KR20220137970A (ko) 2022-10-12
JP7264269B2 (ja) 2023-04-25
CN115298340B (zh) 2023-10-31
BR112022019204A2 (pt) 2022-11-08
CN115298340A (zh) 2022-11-04

Similar Documents

Publication Publication Date Title
EP3604584B1 (de) Hochfeste stahlplatte für sauergasbeständiges leitungsrohr, verfahren zu dessen herstellung und hochfestes stahlrohr unter verwendung der hochfesten stahlplatte für sauergasbeständiges leitungsrohr
CN111094610B9 (zh) 钢管和钢板
EP3859027B1 (de) Hochfeste stahlplatte für sauergas-resistente leitungsrohre und verfahren zu ihrer herstellung, und hochfestes stahlrohr unter verwendung von hochfesten stahlplatten für sauergas-resistente leitungsrohre
EP3816311B1 (de) Stahlrohr und stahlblech
EP3604592B1 (de) Hochfeste stahlplatte für sauergasbeständiges leitungsrohr, verfahren zur herstellung davon und hochfestes stahlrohr aus hochfester stahlplatte für sauergasbeständiges leitungsrohr
EP3128029A1 (de) Stahlmaterial für hochgradig verformbare leitungsrohre mit hervorragenden reckalterungseigenschaften und anti-hic-eigenschaften, verfahren zur herstellung davon und geschweisstes stahlrohr
EP3733894A1 (de) Elektrisch widerstandsgeschweisstes stahlrohr und verfahren zur herstellung eines elektrisch widerstandsgeschweissten stahlrohrs
JP7272442B2 (ja) 耐サワーラインパイプ用高強度鋼板およびその製造方法並びに耐サワーラインパイプ用高強度鋼板を用いた高強度鋼管
EP4129510A1 (de) Hochfestes stahlblech für säureresistentes leitungsrohr, verfahren zur herstellung davon und mit hochfestem stahlblech hergestelltes leitungsrohr für säureresistentes stahlrohr
EP3239320A1 (de) Stahlplatte mit ausgezeichnetem widerstand gegenüber wasserstoffinduzierter rissbildung und stahlrohr für leitungsrohr
EP3859026B1 (de) Hochfeste stahlplatte für sauergas-resistente leitungsrohre und verfahren zu ihrer herstellung, und hochfestes stahlrohr unter verwendung von hochfesten stahlplatten für sauergas-resistente leitungsrohre
JP6665822B2 (ja) 耐サワーラインパイプ用高強度鋼板およびその製造方法並びに耐サワーラインパイプ用高強度鋼板を用いた高強度鋼管
EP3677698A1 (de) Hochfeste stahlplatte für sauergasbeständiges leitungsrohr, verfahren zur herstellung davon und hochfestes stahlrohr mit hochfestem stahlblech für sauergasbeständiges leitungsrohr
EP4116453A1 (de) Stahlrohr und stahlblech
RU2805165C1 (ru) Высокопрочный стальной лист для кислотостойких магистральных труб и способ его изготовления, и высокопрочная стальная труба с использованием высокопрочного стального листа для кислотостойкой магистральной трубы
EP3674433A1 (de) Hochfestes stahlblech für sauergasresistente leitungsrohre und hochfestes stahlrohr damit
EP4321632A1 (de) Hochfestes warmgewalztes stahlblech und herstellungsverfahren dafür sowie hochfestes widerstandsgeschweisstes stahlrohr und herstellungsverfahren dafür

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20221007

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)