WO2019234851A1 - Tuyau en acier soudé par résistance électrique pour puits de pétrole - Google Patents

Tuyau en acier soudé par résistance électrique pour puits de pétrole Download PDF

Info

Publication number
WO2019234851A1
WO2019234851A1 PCT/JP2018/021710 JP2018021710W WO2019234851A1 WO 2019234851 A1 WO2019234851 A1 WO 2019234851A1 JP 2018021710 W JP2018021710 W JP 2018021710W WO 2019234851 A1 WO2019234851 A1 WO 2019234851A1
Authority
WO
WIPO (PCT)
Prior art keywords
pipe
steel pipe
less
content
base material
Prior art date
Application number
PCT/JP2018/021710
Other languages
English (en)
Japanese (ja)
Inventor
健介 長井
幸伸 永田
雅和 尾▲崎▼
Original Assignee
日本製鉄株式会社
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 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to PCT/JP2018/021710 priority Critical patent/WO2019234851A1/fr
Publication of WO2019234851A1 publication Critical patent/WO2019234851A1/fr

Links

Images

Classifications

    • 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
    • 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
    • C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Definitions

  • This disclosure relates to an ERW steel pipe for oil wells.
  • Patent Document 1 as an electric resistance welded steel pipe used for an expandable tubular casing, that is, an electric resistance welded steel pipe for an expanded oil well having excellent pipe expansion performance, C: 0.01 to 0.30 in mass%. %, Si: 0.01 to 0.70%, Mn: 0.5 to 2.0%, Nb: 0.005 to 0.100%, Ti: 0.005 to 0.050%, Al: 0.0.
  • Patent Document 1 discloses an embodiment in which the ferrite fraction of the base metal structure is 50 to 95%.
  • Patent Document 3 is suitable for a steel pipe in which tensile strain of 5% or more is introduced and the yield strength in the compression direction is small, particularly for applications that receive external pressure after being expanded by 10% or more in an oil well or gas well.
  • the component composition of the base material is, by mass%, C: 0.03 to 0.30%, Si: 0.01 to 0.8%, Mn: 0.3 -2.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.01% or less, and further, Nb : 0.1% or less, V: 0.3% or less, Mo: 0.5% or less, Ti: 0.1% or less, Cr: 1.0% or less, Ni: 1.0% or less, Cu: 1 0.0% or less, B: 0.003% or less, Ca: 0.004% or less, or one or more, and the balance is iron and inevitable impurities
  • the tube is obtained by heating in a two-phase region of austenite and
  • Patent Document 1 Japanese Patent No. 5014831
  • Patent Document 2 Japanese Patent No. 4943325
  • Patent Document 3 Japanese Patent No. 4833835
  • the subject of this indication is providing the electric-welded steel pipe for oil wells which is excellent in pipe expandability, and excellent in the compression yield strength of the pipe circumference direction after pipe expansion.
  • Means for solving the above problems include the following aspects. ⁇ 1> Including the base metal part and the ERW weld part
  • the chemical composition of the base material part is mass%, C: 0.010 to 0.100%, Si: 0 to 0.50%, Mn: 0.30 to 2.00% P: 0 to 0.0300%, S: 0 to 0.0100%, Al: 0.010 to 0.100%, B: 0.0007 to 0.0100%, Ti: 0 to 0.050%, Nb: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Mo: 0 to 0.30%, Cr: 0 to 0.50%, V: 0 to 0.100%, Ca: 0 to 0.0060%, and balance: Fe and impurities, satisfying the following formula (1), ⁇ represented by the following formula (2) is 1.8 or more,
  • the metal structure of the base material part is a tempered martensite structure, ERW steel pipe for oil wells having a yield strength in the pipe
  • ⁇ 3> The electric well welded steel pipe according to ⁇ 1> or ⁇ 2>, wherein the yield ratio in the pipe axis direction is 85 to 95%.
  • ⁇ 4> The electric well-welded steel pipe for oil wells according to ⁇ 3>, wherein a yield ratio in the pipe axis direction is 90 to 95%.
  • ⁇ 5> The oil well according to any one of ⁇ 1> to ⁇ 4>, wherein the compressive yield strength in the pipe circumferential direction measured in a state where the outer diameter is expanded by 15% is 500 to 800 MPa. ERW steel pipe.
  • the content of C in the chemical composition of the base material part is 0.010 to 0.080% by mass%, and The electric well-welded steel pipe for oil wells according to ⁇ 5>, wherein the compressive yield strength in the pipe circumferential direction measured in a state where the outer diameter is expanded by 15% is 570 to 800 MPa.
  • the content of C in the chemical composition of the base material part is 0.010 to 0.050% by mass%, and The electric well-welded steel pipe for oil wells according to ⁇ 6>, wherein the compressive yield strength in the pipe circumferential direction, measured in a state where the outer diameter is expanded by 15%, is 620 to 800 MPa.
  • an electric well-welded steel pipe for oil wells that is excellent in pipe expandability and excellent in compressive yield strength in the pipe circumferential direction after pipe expansion.
  • SEM scanning electron microscope
  • a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
  • “%” indicating the content of a component (element) means “% by mass”.
  • the content of C (carbon) may be expressed as “C amount”.
  • the content of other elements may be expressed in the same manner.
  • the term “process” is not limited to an independent process, and is included in this term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. It is.
  • the concept of “electric well-welded steel pipe” includes not only an electric-welded steel pipe used for oil wells but also an electric-welded steel pipe used for gas wells.
  • the oil well electric-welded steel pipe of the present disclosure (hereinafter also simply referred to as “electric-welded steel pipe”) includes a base metal part and an electric-welded weld part, and the chemical composition of the base metal part is C: 0.010 in mass%.
  • Si 0 to 0.50%
  • Mn 0.30 to 2.00%
  • P 0 to 0.0300%
  • S 0 to 0.0100%
  • Al 0.010 to 0.100%
  • B 0.0007 to 0.0100%
  • Ti 0 to 0.050%
  • Nb 0 to 0.100%
  • Ni 0 to 0.50%
  • Cu 0 to 0.50 %
  • Mo 0 to 0.30%
  • Cr 0 to 0.50%
  • V 0 to 0.100%
  • Ca 0 to 0.0060%
  • Fe and impurities Fe and impurities.
  • ⁇ expressed by the following formula (2) is 1.8 or more
  • the metal structure of the base material part is a tempered martensite structure
  • yield in the tube axis direction Degree (hereinafter also referred to as "YS") is 550 ⁇ 800MPa.
  • the above-described chemical composition of the base material part (including satisfying the formula (1) and ⁇ being 1.8 or more) is also referred to as “chemical composition in the present disclosure”.
  • the electric resistance steel pipe of this indication contains a base material part and an electric resistance welding part.
  • ERW steel pipes are generally made into open pipes by forming hot-rolled steel sheets into tubes (hereinafter also referred to as “roll forming”). It is manufactured by forming an electric resistance welded portion and then, if necessary, seam heat treating the electro-welded weld.
  • the base metal portion refers to a portion other than the ERW weld and the heat affected zone.
  • the heat affected zone (hereinafter also referred to as “HAZ”) is the effect of heat by electric resistance welding (when seam heat treatment is performed after electric resistance welding, heat generated by electric resistance welding and seam heat treatment).
  • the electric resistance welded portion may be simply referred to as a “welded portion”.
  • the electric resistance welded steel pipe of the present disclosure is excellent in pipe expandability and excellent in compressive yield strength in the pipe circumferential direction after pipe expansion. Since the electric resistance welded steel pipe of the present disclosure is excellent in pipe expandability and excellent in the compressive yield strength in the pipe circumferential direction after the pipe expansion, for example, expandable tubular technology (that is, by expanding the steel pipe in the oil well, When used for oil well finishing or repair), it has excellent crushing characteristics after pipe expansion.
  • the pressure-proof crushing property means resistance to collapse (that is, crushing due to external pressure).
  • Tube expandability, pipe expansion rate is excellent in tube expandability means that the tube can be expanded at a high tube expansion rate (for example, a tube expansion rate of 16% or more) without causing cracks.
  • the effect of excellent pipe expandability is mainly due to
  • the chemical composition of the base material part is the chemical composition in the present disclosure;
  • the YS in the tube axis direction is 800 MPa or less, Achieved by a combination of
  • the chemical composition of the base material part is the chemical composition in the present disclosure (in particular, the C content is 0.100% or less);
  • the metal structure of the base metal part is a tempered martensite structure,
  • the YS in the tube axis direction is 550 MPa or more; Achieved by a combination of
  • the compressive yield strength in the pipe circumferential direction after expanding the steel pipe is not determined only by the strength (for example, YS) of the steel pipe, but is strongly influenced by the Bauschinger effect due to the expansion. More specifically, in order to improve the compressive yield strength in the pipe circumferential direction of the steel pipe, it is particularly effective to suppress the Bausinger effect due to the pipe expansion.
  • a tempered martensite structure (that is, a single-phase structure made of tempered martensite) has a lower Bausinger effect and a ferrite single-phase structure than a two-phase structure (for example, a two-phase structure made of tempered martensite and ferrite).
  • the strength (for example, YS) is higher than that of the phase structure.
  • the tempered martensite structure is advantageous in increasing the compressive yield strength in the pipe circumferential direction after pipe expansion.
  • tempered martensite with a low C content was found to have a lower Bausinger effect compared to tempered martensite with a high C content. The reason for this is not clear, but tempered martensite with a low C content is less likely to generate internal stress because of its low cementite content. As a result, it is considered that the Bauschinger effect is reduced.
  • FIG. 1 shows the results of a basic experiment conducted by the present inventors.
  • the C content (%) and the stress due to the Bausinger effect It is a graph which shows an example of a relationship with a fall amount (MPa).
  • This basic experiment was performed as follows. Quenched and tempered electric-welded steel pipe (ie, metal in the base metal part) having a C content (%) in the chemical composition of the base metal part of 0.03%, 0.10%, and 0.40% Each structure prepared ERW steel pipe which is tempered martensite structure).
  • the chemical composition of the base metal part of these ERW steel pipes is substantially the same chemical composition except for the C content (%), and the chemical composition in the present disclosure is satisfied except for the C content (%). Adjusted.
  • the YS in the tube axis direction of these ERW steel pipes was 634 MPa (C: 0.03%), 707 MPa (C: 0.10%), and 733 MPa (C: 0.40%), respectively.
  • the heating temperature in quenching was 950 ° C., and the heating temperature in tempering was 650 ° C.
  • a round bar tensile test piece having a parallel portion diameter of 6.0 mm and an axial length of 12.0 mm was collected from the base material portion of each electric resistance steel pipe.
  • the electric resistance welded steel pipe of the present disclosure is excellent in compressive yield strength in the pipe circumferential direction after pipe expansion. More specifically, the electric resistance welded steel pipe of the present disclosure preferably has a compressive yield strength in the pipe circumferential direction measured in a state where the outer diameter is expanded by 15% in a range of 500 to 800 MPa.
  • the state where the pipe is expanded so that the outer diameter is increased by 15% means a state where the pipe is expanded so that the above-described pipe expansion rate is 15%.
  • the compressive yield strength in the pipe circumferential direction measured in a state where the outer diameter is expanded so as to be expanded by 15% is also referred to as “15% expanded compressive yield strength”.
  • the compression yield strength at the time of 15% tube expansion of 500 MPa or more means that the compression yield strength in the pipe circumferential direction after tube expansion is superior.
  • the compression yield strength at the time of 15% pipe expansion is more preferably 550 MPa or more, further preferably 570 MPa or more, further preferably 600 MPa or more, further preferably, from the viewpoint of the compressive yield strength in the pipe circumferential direction after the pipe expansion. It is 620 MPa or more.
  • the upper limit value (800 MPa) of the compression yield strength at the time of 15% pipe expansion is an upper limit value that is provided in consideration of the suitability for manufacturing an ERW steel pipe.
  • the upper limit value of the compression yield strength at the time of 15% pipe expansion is preferably 790 MPa from the viewpoint of the suitability for manufacturing an ERW steel pipe.
  • the compression yield strength at the time of 15% pipe expansion (that is, the compressive yield strength in the pipe circumferential direction measured with the outer diameter expanded by 15%) is measured as follows. Value.
  • the electric resistance welded steel pipe of the present disclosure is expanded by a hydraulic expansion test so that the outer diameter is expanded by 15%.
  • the diameter of the parallel portion is 6.0 mm from each of the base material 90 ° position, the base material 180 ° position, and the base material 270 ° position in the expanded ERW steel pipe, and the parallel portion has an axial length of 12 mm. Take a round bar compression test piece of 0.0 mm.
  • Each round bar compression test piece is sampled in such a direction that the axial direction of each round bar compression test piece is the pipe circumferential direction of the ERW steel pipe.
  • Each of the three round bar compression test pieces is subjected to the following compression test to determine the offset proof stress (MPa) at 0.05% strain.
  • MPa offset proof stress
  • the arithmetic average value of the obtained three measured values is obtained, and the obtained arithmetic average value is taken as the compression yield strength at the time of 15% expansion of the ERW steel pipe.
  • the test direction (that is, the compression direction) is the axial direction of the round bar compression test piece (that is, the direction corresponding to the circumferential direction of the ERW steel pipe), and the stroke speed during compression is 0.1 mm. / Min.
  • a load-displacement curve is obtained by the compression test, and a stress value (MPa) at 0.05% strain is read from the obtained load-displacement curve.
  • Base material 90 ° position means a position in the base material portion that is shifted by 90 ° from the ERW weld portion in the pipe circumferential direction
  • Base material 180 ° position means a position in the base material portion that is 180 ° shifted from the ERW weld portion in the pipe circumferential direction
  • the “base metal 270 ° position” means a position in the base metal portion that is displaced by 270 ° in the pipe circumferential direction from the ERW weld.
  • C 0.010 to 0.100% C is an element that improves the strength of steel. If the C content is less than 0.010%, the strength of the steel may not be sufficient. Therefore, the C content is 0.010% or more.
  • the C content is preferably 0.0011% or more, and more preferably 0.0012% or more.
  • the Bauschinger effect due to the pipe expansion becomes remarkable, and as a result, the compressive yield strength in the pipe circumferential direction after the pipe expansion may decrease. Therefore, the C content is 0.100% or less.
  • the C content is preferably 0.080% or less, more preferably 0.060% or less, and still more preferably 0.050% from the viewpoint of further improving the compressive yield strength in the pipe circumferential direction after pipe expansion. It is as follows. As a particularly preferred embodiment of the electric resistance welded steel pipe of the present disclosure, the C content is 0.010 to 0.080% (more preferably 0.010 to 0.060%, still more preferably 0.010 to 0.050%). And a compression yield strength at 15% tube expansion of 570 to 800 MPa (more preferably 600 to 800 MPa, still more preferably 620 to 800 MPa).
  • Si 0 to 0.50% Si is an element that can function as a deoxidizer for steel. If the Si content exceeds 0.50%, inclusions may be generated in the ERW weld and expansion may not be possible. Accordingly, the Si content is 0.50% or less. Si content becomes like this. Preferably it is 0.48% or less, More preferably, it is 0.46% or less. The Si content may be 0% by mass. The Si content may be more than 0%, 0.01% or more, or 0.05% or more.
  • Mn 0.30 to 2.00%
  • Mn is an element that can improve the hardenability of steel. Further, Mn is an element that has an effect of detoxifying S in addition to the effect of increasing hardenability. From the viewpoint of obtaining these effects, the Mn content is 0.30% or more.
  • the Mn content is preferably 1.00% or more, more preferably 1.40% or more.
  • Mn content is 2.00% or less.
  • the Mn content is preferably 1.90%.
  • P 0 to 0.0300%
  • P is an element that can exist as an impurity in steel. If the P content exceeds 0.0300%, pipe expandability may be impaired due to segregation at grain boundaries. Therefore, the P content is 0.0300% or less.
  • the P content is preferably 0.0290%, more preferably 0.0250% or less.
  • the P content may be 0%. From the viewpoint of reducing the dephosphorization cost, the P content may be more than 0%, 0.0001% or more, or 0.0010% or more.
  • S 0 to 0.0100% S is an element that can exist as an impurity in steel. If the S content exceeds 0.0100%, coarse MnS may be generated in the center segregation part or the ERW weld part, and the pipe expandability may deteriorate. Accordingly, the S content is 0.0100% or less.
  • the S content is preferably 0.0090% or less, and more preferably 0.0080% or less.
  • the S content may be 0%. From the viewpoint of reducing the desulfurization cost, the S content may be more than 0%, 0.0001% or more, or 0.0010% or more.
  • Al 0.010 to 0.100%
  • Al is an element that can function as a deoxidizer. From the viewpoint of exerting such a function, the Al content is 0.010% or more.
  • the Al content is preferably 0.015% or more, and more preferably 0.020% or more.
  • Al content is 0.100% or less.
  • the Al content is preferably 0.090% or less.
  • B 0.0007 to 0.0100%
  • B is an element that greatly improves the hardenability and increases the strength of the steel by containing a small amount. From the viewpoint of exhibiting such an effect, the B content is 0.0007% or more.
  • the B content is preferably 0.0010% or more, and more preferably 0.0020% or more.
  • the B content is 0.0100% or less.
  • the B content is preferably 0.0080% or less, and more preferably 0.0060% or less.
  • Ti 0 to 0.050%
  • Ti is an arbitrary element. Therefore, the Ti content may be 0%.
  • Ti is an element that forms carbonitrides, contributes to refinement of crystal grain size, and contributes to improvement of steel strength. Moreover, Ti suppresses the generation
  • Nb 0 to 0.100%
  • Nb is an arbitrary element. Therefore, the Nb content may be 0%.
  • Nb is an element that contributes to strength improvement and toughness improvement. From the viewpoint of obtaining such an effect, the Nb content may be more than 0% or 0.010% or more.
  • the Nb content is 0.100% or less.
  • the Nb content is preferably 0.080% or less.
  • Ni 0 to 0.50%
  • Ni is an arbitrary element. Therefore, the Ni content may be 0%.
  • Ni is an element that contributes to improving hardenability and contributes to improving the strength of steel. From the viewpoint of obtaining such an effect, the Ni content may be more than 0% or 0.05% or more.
  • the Ni content is 0.50% or less.
  • the Ni content is preferably 0.40% or less.
  • Cu 0 to 0.50% Cu is an arbitrary element. Therefore, the Cu content may be 0%.
  • Cu is an element that contributes to improving hardenability and contributes to improving the strength of steel. From the viewpoint of obtaining such an effect, the Cu content may be more than 0% or 0.05% or more.
  • the Cu content if the Cu content exceeds 0.50%, fine Cu particles are generated, and the compression yield strength in the pipe circumferential direction after pipe expansion may be significantly deteriorated. Therefore, the Cu content is 0.50% or less. Cu content becomes like this. Preferably it is 0.40% or less, More preferably, it is 0.20% or less, More preferably, it is 0.10% or less.
  • Mo 0 to 0.30%
  • Mo is an arbitrary element. Therefore, the Mo content may be 0%. Mo is an element that contributes to improving hardenability and contributes to improving the strength of steel. From the viewpoint of obtaining such an effect, the Mo content may be more than 0% or 0.01% or more. On the other hand, if the Mo content exceeds 0.30%, the compression yield strength in the pipe circumferential direction after pipe expansion may be reduced due to the formation of Mo carbonitride. Therefore, the Mo content is 0.30% or less. The Mo content is preferably 0.20% or less.
  • Cr 0 to 0.50% Cr is an arbitrary element. Therefore, the Cr content may be 0%. Cr is an element that contributes to improving the hardenability and contributes to improving the strength of the steel. From the viewpoint of obtaining such an effect, the Cr content may be more than 0% or 0.05% or more. On the other hand, if the Cr content exceeds 0.50%, the pipe expandability may be reduced by the Cr-based inclusions generated in the ERW weld. Therefore, the Cr content is 0.50% or less. The Cr content is preferably 0.40%, more preferably 0.30% or less.
  • V 0 to 0.100%
  • V is an arbitrary element. Therefore, the V content may be 0%.
  • V is an element that has substantially the same effect as Nb (that is, improved strength and improved toughness) and has an effect of suppressing softening of the weld. From the viewpoint of obtaining these effects, the V content may be more than 0% or 0.010% or more.
  • the V content exceeds 0.100%, the V carbonitride may reduce the compressive yield strength in the pipe circumferential direction after pipe expansion. Therefore, the V addition amount is 0.100% or less.
  • the V content is preferably 0.070% or less.
  • Ca 0 to 0.0060%
  • Ca is an arbitrary element. Therefore, the Ca content may be 0%.
  • Ca is an element that controls the form of sulfide inclusions, and is an element that improves the strength and low-temperature toughness of steel. From the viewpoint of obtaining these effects, the Ca content may be more than 0% or 0.0010% or more.
  • the Ca content exceeds 0.0060%, CaO—CaS becomes large clusters or large inclusions, which may adversely affect tube expandability. Therefore, the Ca content is 0.0060% or less.
  • the Ca content is preferably 0.0050% or less.
  • the remainder excluding the above-described elements is Fe and impurities.
  • the impurity refers to a component contained in the raw material or a component mixed in the manufacturing process and not intentionally contained in the steel.
  • impurities include all elements other than the elements described above.
  • the element as the impurity may be only one type or two or more types.
  • the impurities include O (oxygen), N (nitrogen), Mg, REM, Sb, Sn, W, Co, As, Pb, Bi, and H (hydrogen).
  • REM is a rare earth element, that is, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It refers to at least one element selected.
  • O is preferably controlled so that the content is 0.006% or less.
  • N is preferably controlled so that the content is 0.010% or less.
  • Mg and REM are mixed with a content of 0.01% or less, for example, Sb, Sn, W, Co, and As are mixed with a content of 0.1% or less.
  • the chemical composition of the base metal part is, in mass%, Ti: more than 0% and less than 0.050%, Nb: more than 0% and less than 0.100%, Ni: more than 0% and 0%. .50% or less, Cu: more than 0% to 0.50% or less, Mo: more than 0% to 0.30% or less, Cr: more than 0% to 0.50% or less, V: more than 0% to 0.100% or less, and Ca: You may contain 1 type or 2 types or more of more than 0% and 0.0060% or less. The preferable ranges of the contents of these elements are as described above.
  • each element symbol (Mn and Si) is the mass% of each element (Mn and Si). That is, the formula (1) means that the ratio of the mass% of Mn to the mass% of Si (in this specification, this ratio is “Mn / Si”) is more than 2.0. Yes. If Mn / Si is 2.0 or less, MnSi-based inclusions are generated in the welded portion, and cracks may occur during pipe expansion. Therefore, Mn / Si is over 2.0. Mn / Si is preferably 2.2 or more. There is no restriction
  • ⁇ 1.8 or more
  • ⁇ represented by the following formula (2) is 1.8 or more.
  • each element symbol means the mass% of each element.
  • ⁇ is an index related to the hardenability of the steel material, and the higher the value, the higher the hardenability.
  • the metal structure of the base material part in the present disclosure is a tempered martensite structure. If ⁇ is less than 1.8, a tempered martensite structure may not be obtained. When ⁇ is less than 1.8, for example, a two-phase structure composed of bainite and tempered martensite may be formed. Therefore, from the viewpoint of making the metal structure of the base material part a tempered martensite structure, in the chemical composition of the present disclosure, ⁇ is 1.8 or more. There is no particular limitation on the upper limit of ⁇ . For example, the upper limit of ⁇ may be 3.0 or 2.6.
  • the metal structure of the base material part in the present disclosure is a tempered martensite structure.
  • the tempered martensite structure means a single-phase structure composed of tempered martensite. That is, the metal structure of the base material part in the present disclosure does not include structures other than tempered martensite (for example, ferrite, upper bainite (hereinafter, also simply referred to as “bainite”), and the like).
  • the metal structure of a base material part is comprehensively determined based on the scanning electron microscope (SEM) photograph and the optical microscope photograph, and the YS value in the tube axis direction of the ERW steel pipe.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • discrimination between tempered martensite and martensite is performed by regarding the case where cementite can be confirmed on the SEM photograph as tempered martensite. Cementite is confirmed as a white spot in the SEM photograph.
  • tempered martensite and ferrite can be discriminated on the SEM photograph. If the lath structure can be confirmed by SEM photographs, it is tempered martensite, and if the lath structure cannot be confirmed, it is ferrite. If this standard cannot be discriminated, TEM observation is performed. If dislocation can be confirmed on the TEM photograph, it is tempered martensite, and if dislocation cannot be confirmed, it is ferrite.
  • tempered martensite and bainite discrimination between tempered martensite and bainite (ie, upper bainite) is considered as bainite when the preferential growth orientation of cementite precipitated in Lath is unidirectionally oriented in TEM on the TEM photograph.
  • the case where the preferred growth orientation of the precipitated cementite is random is regarded as tempered martensite.
  • an SEM photograph and an optical microscope photograph for determining the metal structure of the base metal part an SEM photograph and an optical microscope obtained by photographing a metal structure at a thickness of 1/4 in the L cross section of the base metal 90 ° position of the ERW steel pipe Use photos.
  • the L cross section means a cross section parallel to the tube axis direction and the thickness direction.
  • the wall thickness 1/4 position means a position where the distance from the outer peripheral surface of the ERW steel pipe is 1/4 of the wall thickness.
  • the meaning of the base material 90 ° position is as described above.
  • the L cross section of the base material 90 ° position of the ERW steel pipe is polished and then etched by nital.
  • SEM observation and optical microscope observation are respectively performed on the etched 1/4 thickness position in the L cross section, and an SEM photograph (magnification 2000 times) and an optical microscope photograph (magnification 500 times) are respectively taken.
  • the metal structure at the 1/4 thickness position is determined.
  • the determined metal structure is taken as the metal structure of the base material part.
  • the determination of the metal structure is comprehensively performed in consideration of not only the SEM photograph and the optical microscope photograph but also the YS value in the tube axis direction.
  • FIG. 2 shows a metal structure of a base material part (specifically, a thickness 1/4 position in the L cross section of the base material at 90 ° position) in an example of an electric resistance welded steel pipe of the present disclosure (Example 3 described later). It is a scanning electron microscope (SEM) photograph (2000-times multiplication factor).
  • FIG. 3 shows a metal structure of a base material portion (specifically, a thickness 1/4 position in the L cross section of the base material at a 90 ° position) in an example of the electric resistance welded steel pipe of the present disclosure (Example 3 described later). It is an optical micrograph (magnification 500 times). In FIG. 3, “20 ⁇ m” means 20 ⁇ m.
  • the metal structure (Example 3 described later) in the above example is determined to be a single-phase structure composed of tempered martensite.
  • the electric resistance welded steel pipe of the present disclosure has a yield strength (YS) in the pipe axis direction of 550 to 800 MPa.
  • the YS in the pipe axis direction is 550 MPa or more, so that the strength required as an ERW steel pipe for oil wells is ensured, and the compressive yield strength in the pipe circumferential direction after pipe expansion is improved.
  • the YS in the tube axis direction is preferably 580 MPa or more, more preferably 600 MPa or more, and further preferably 610 MPa or more.
  • the pipe expandability is improved when the YS in the pipe axis direction is 800 MPa or less.
  • YS in the tube axis direction is preferably 750 MPa or less, and more preferably 700 MPa or less.
  • the metal structure of the base material portion is a tempered martensite structure, and the YS in the pipe axis direction is 550 to 800 MPa. It shows that this is an electric resistance steel pipe obtained by quenching and tempering (As-rolled electric resistance welded steel pipe).
  • the as-roll ERW steel pipe refers to an ERW steel pipe that has not been subjected to heat treatment other than seam heat treatment after pipe making.
  • “Pipe making” refers to a process from forming a hot rolled steel sheet into an open pipe by roll forming, and forming an electric resistance welded portion by electro-welding the butt portion of the obtained open pipe.
  • YS in the tube axis direction and TS in the tube axis direction described later mean values measured as follows.
  • a JIS No. 4 sub-size round bar tensile test piece is taken from the 90 ° position of the base metal in the ERW steel pipe.
  • collected JIS4 subsize round bar tensile test piece the tensile test of a pipe axis direction is done based on JISZ2241 (2011), and YS and TS of a pipe axis direction are each measured.
  • the electric resistance welded steel pipe of the present disclosure preferably has a tensile strength (TS) in the pipe axis direction of 600 to 850 MPa.
  • the TS in the tube axis direction is more preferably 620 MPa or more.
  • the TS in the tube axis direction is more preferably 810 MPa or less.
  • the TS of 600 to 850 MPa in the pipe axis direction can be achieved by quenching and tempering after pipe making.
  • the YR in the tube axis direction is more preferably 89% or more, and still more preferably 90% or more.
  • the YR in the tube axis direction is 95% or less, the tube expandability is further improved.
  • the YR in the tube axis direction is more preferably 94% or less, still more preferably 93% or less.
  • the YR in the pipe axis direction of 85 to 95% can be achieved by quenching and tempering after pipe making when obtaining the electric resistance welded steel pipe of the present disclosure.
  • the wall thickness of the electric resistance welded steel pipe of the present disclosure is preferably 8.0 to 20.0 mm.
  • the wall thickness is more preferably 10.0 mm or more.
  • the wall thickness is 20.0 mm or less, it is advantageous in terms of the suitability for producing an electric resistance welded steel pipe (specifically, the formability when roll-forming a hot-rolled steel sheet).
  • the outer diameter of the electric resistance welded steel pipe of the present disclosure is preferably 152.4 to 406.4 mm (ie, 6 to 16 inches). When the outer diameter is 152.4 mm or more, it is more suitable as an electric-welded steel pipe for oil wells.
  • the outer diameter is more preferably 203.2 mm (that is, 8 inches) or more.
  • the outer diameter is 406.4 mm or less, it is advantageous in terms of the suitability for manufacturing an electric resistance welded steel pipe.
  • the outer diameter is preferably 355.6 mm (ie, 14 inches) or less.
  • the electric resistance steel pipe of the present disclosure is manufactured by quenching and tempering the as-roll electric resistance steel pipe. Whether or not the target electric resistance welded steel pipe is manufactured by quenching and tempering the as-rolled electric resistance welded steel pipe can be confirmed as follows.
  • a tensile test in the pipe axis direction is performed in the same manner as the above-described measurement of YS and TS. In the tensile test, it is confirmed whether substantial yield elongation (specifically, yield elongation of 0.1% or more) is observed.
  • substantial yield elongation specifically, yield elongation of 0.1% or more
  • substantial yield elongation is observed during the tensile test.
  • the target ERW steel pipe is an as-roll ERW steel pipe (including the case where it is an as-roll ERW steel pipe manufactured using a tempered hot-rolled steel sheet), at the time of the tensile test, Typical yield elongation is not observed.
  • the electric resistance welded steel pipe of the present disclosure is an electric resistance welded steel pipe, it is excellent in uneven thickness compared with a seamless steel pipe.
  • the excellent thickness deviation is advantageous in terms of the compressive yield strength in the pipe circumferential direction after pipe expansion.
  • the thickness deviation of the electric resistance welded steel pipe of the present disclosure is preferably in the range of 0.1 to 3.0%, more preferably in the range of 0.3 to 2.5%. When the thickness deviation is in this range, the compressive yield strength in the pipe circumferential direction after pipe expansion is further improved.
  • the thickness deviation can be measured by the following method.
  • the thickness measurement position is selected at a 15 ° pitch in the pipe circumferential direction starting from the ERW weld.
  • Process A is Preparing an azurol ERW steel pipe having a chemical composition in the present disclosure; A quenching and tempering step for obtaining an ERW steel pipe of the present disclosure by quenching and tempering the as-rolled ERW steel pipe, including.
  • the quenching and tempering process The as-rolled electric resistance welded steel pipe is heated to a heating temperature in the range of A3 point or more and A3 point + 100 ° C or less, then cooled to a cooling rate change temperature of 750 ° C or more, and then from the cooling rate change temperature of 50 ° C / s or more.
  • An as-roll electric resistance welded steel pipe is formed as an open pipe by roll-forming a hot-rolled steel sheet having the chemical composition in the present disclosure, and the butt portion of the obtained open pipe is electro-welded to form an electric-welded weld, and then required Accordingly, it is manufactured by performing seam heat treatment on the ERW weld. If necessary, the size reduction and / or shape adjustment by the sizer may be applied to the as-rolled ERW steel pipe after forming the ERW weld (but after seam heat treatment if seam heat treatment is performed). .
  • the as-rolled ERW steel pipe is heated to a heating temperature in the range of A3 point to A3 point + 100 ° C., then cooled to a cooling rate change temperature of 750 ° C. or more, and then from the above cooling rate change temperature.
  • the A3 point means a temperature at which transformation to austenite is completed during heating.
  • the A3 point is calculated by the following formula based on the chemical composition in the present disclosure.
  • the strain introduced in the pipe making is completely removed, and the metal structure of the base material part of the as-rolled ERW steel pipe is Transform to austenite.
  • Heating is performed in a heating furnace.
  • the holding time at the heating temperature is preferably 5 minutes or more and 60 minutes or less.
  • the heated as-rolled ERW steel pipe is cooled (for example, air-cooled), for example, over several seconds to several tens of seconds to a cooling rate change temperature of 750 ° C. or higher after exiting the heating furnace, and then from the cooling rate change temperature, 50 Cooling to a cooling end temperature (for example, room temperature) of 100 ° C. or lower at a cooling rate of at least ° C./s
  • a cooling end temperature for example, room temperature
  • Tempering in the quenching and tempering process is a process for obtaining the ERW steel pipe of the present disclosure by heating the as-rolled ERW steel pipe subjected to the above quenching to a heating temperature in the range of 300 ° C. or higher and A1 or lower and then cooling.
  • the A1 point means a temperature at which austenite starts to be generated during heating.
  • the A1 point is calculated by the following formula based on the chemical composition in the present disclosure.
  • the holding time at the heating temperature is preferably 5 minutes or more and 60 minutes or less.
  • the cooling is not particularly limited, and may be slow cooling or rapid cooling.
  • the metal structure (martensite) of the base material portion obtained by the above-described quenching is changed to tempered martensite by the above tempering, and the ERW steel pipe of the present disclosure is obtained.
  • the chemical composition of the base material part of the ERW steel pipe manufactured by the manufacturing method A is the same as the chemical composition of the base material part of the as-roll ERW steel pipe as a raw material. The reason is that quenching and tempering in production method A does not affect the chemical composition of the steel.
  • RT means room temperature.
  • RT room temperature
  • Example 1 to 20 Comparative Examples 1 to 18
  • ERW steel pipes having an outer diameter of 279.4 mm and a wall thickness of 15.9 mm were manufactured according to the above-mentioned production method A.
  • the outer diameter was 279.4 mm and the wall thickness was 15.9 mm, as in Production Method A, except that at least one production condition (including the chemical composition of the base material part) was changed.
  • An electric resistance welded steel pipe was manufactured. Details will be described below.
  • TM means a single-phase structure consisting of tempered martensite
  • M means a single-phase structure composed of martensite
  • F + TM means a two-phase structure composed of ferrite and tempered martensite
  • B + TM means a two-phase structure consisting of bainite and tempered martensite
  • B + M means a two-phase structure composed of bainite and martensite.
  • Tube expansion with a tube expansion rate of 16% was possible without causing cracks, and the tube expandability was good.
  • B Cracking occurred at the time of tube expansion with a tube expansion rate of 16%, or tube expansion with a tube expansion rate of 16% could not be performed, and tube expandability was insufficient.
  • the chemical composition of the base material part is the chemical composition in the present disclosure
  • the metal structure of the base material part is a tempered martensite structure (that is, a single-phase structure composed of tempered martensite).
  • the ERW steel pipes of Examples 1 to 20 having a YS in the pipe axis direction of 550 to 800 MPa are excellent in pipe expandability and have 15% pipe compressive yield strength (that is, compressive yield in the pipe circumferential direction after pipe expansion). Strength).
  • Comparative Example 5 In Comparative Example 5 in which the Mn content exceeded the upper limit, cracks occurred during tube expansion, and the tube expandability deteriorated. It is thought that the crack at the time of pipe expansion is caused by center segregation. In Comparative Example 6 in which the P content exceeded the upper limit, cracks occurred during tube expansion, and the tube expandability deteriorated. It is considered that the cracks at the time of pipe expansion are due to embrittlement due to grain boundary segregation. In Comparative Example 7 in which the S content exceeded the upper limit, cracks occurred during tube expansion, and the tube expandability deteriorated. It is thought that the crack at the time of pipe expansion is caused by center segregation.
  • Comparative Example 8 in which the Al content was below the lower limit, cracks occurred during tube expansion, and the tube expandability deteriorated.
  • the crack at the time of pipe expansion is considered to be due to insufficient deoxidation and the formation of voids in the structure of the cast slab which is the raw material of the ERW steel pipe.
  • Comparative Example 9 in which the Al content exceeded the upper limit, cracks due to welding defects occurred during pipe expansion, and the pipe expandability deteriorated.
  • Comparative Example 10 in which the B content is lower than the upper limit, the hardenability is insufficient, and the metal structure of the base material portion is not a single-phase structure composed of tempered martensite, but a two-phase structure composed of bainite and tempered martensite. It became.
  • Comparative Example 10 the compression yield strength at 15% tube expansion was insufficient. The reason for this is thought to be that the Bausinger effect became prominent.
  • Comparative Example 11 in which the B content exceeded the upper limit, B precipitates were formed and the hardenability was insufficient.
  • the metal structure of the base material portion did not become a single-phase structure composed of tempered martensite. A two-phase structure consisting of tempered martensite was obtained.
  • Comparative Example 11 the compression yield strength during 15% tube expansion was insufficient. The reason for this is thought to be that the Bausinger effect became prominent.
  • the metal structure of the base material part is a two-phase structure composed of ferrite and tempered martensite, and the metal structure of the base material part is bainite and tempered.
  • Comparative Examples 15 and 16 which are two-phase structures composed of martensite, the compression yield strength at 15% expansion was insufficient. The reason for this is thought to be that the Bausinger effect became prominent.
  • Comparative Example 14 the reason why the metal structure of the base material part became a two-phase structure composed of ferrite and tempered martensite is considered to be because the cooling rate change temperature in quenching was too low.
  • Comparative Example 15 the reason why the metal structure of the base material part became a two-phase structure composed of bainite and tempered martensite is considered that the cooling rate in quenching was too low.
  • Comparative Example 16 the reason why the metal structure of the base material part became a two-phase structure composed of bainite and tempered martensite is considered to be because the cooling end temperature in quenching was too high.
  • the metal structure of the base material part of Comparative Example 17 was a single-phase structure composed of martensite (that is, martensite that was not tempered). This is probably because tempering was not performed.
  • the metal structure of the base material part of Comparative Example 18 was a two-phase structure composed of bainite and martensite (that is, martensite that was not tempered). The reason for this is considered that the cooling end temperature in quenching is too high and tempering was not performed.
  • the thickness deviation was measured by the method described above. As a result, in all the examples, the thickness deviation was in the range of 0.5 to 2.5%.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

L'invention concerne un tuyau en acier soudé par résistance électrique pour puits de pétrole, qui comprend une partie de matrice et une partie soudée par résistance électrique, la composition chimique de la partie de matrice comprenant, en % en masse, 0,010 à 0,100 % de C, 0,30 à 2,00 % de Mn, 0,010 à 0,100 % d'Al, 0,0007 à 0,0100 % de B et un reste constitué de Fe et d'impuretés, l'exigence représentée par la formule (1) étant satisfaite, la valeur ß exprimée par la formule (2) étant de 1,8 ou plus, la structure métallique de la partie de matrice étant une structure de martensite revenue et la limite d'élasticité dans la direction de l'axe du tuyau étant de 550 à 800 MPa. Dans la formule (1) et la formule (2), chaque symbole d'élément représente une valeur de % en masse de chaque élément. Formule (1) : Mn/Si > 2,0 Formule (2) : ß = 2,7C + 0,4Si + Mn + 0,45Ni + 0,45Cu + 0,8Cr + 2Mo
PCT/JP2018/021710 2018-06-06 2018-06-06 Tuyau en acier soudé par résistance électrique pour puits de pétrole WO2019234851A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2018/021710 WO2019234851A1 (fr) 2018-06-06 2018-06-06 Tuyau en acier soudé par résistance électrique pour puits de pétrole

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2018/021710 WO2019234851A1 (fr) 2018-06-06 2018-06-06 Tuyau en acier soudé par résistance électrique pour puits de pétrole

Publications (1)

Publication Number Publication Date
WO2019234851A1 true WO2019234851A1 (fr) 2019-12-12

Family

ID=68769813

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/021710 WO2019234851A1 (fr) 2018-06-06 2018-06-06 Tuyau en acier soudé par résistance électrique pour puits de pétrole

Country Status (1)

Country Link
WO (1) WO2019234851A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006132441A1 (fr) * 2005-06-10 2006-12-14 Nippon Steel Corporation Tuyau de puits de pétrole pour utilisation en tube extensible d’une excellente robustesse après expansion du tube et procédé de fabrication idoine
JP2010001566A (ja) * 2008-05-19 2010-01-07 Nippon Steel Corp 低降伏比高強度電縫鋼管及びその製造方法
JP2015168864A (ja) * 2014-03-07 2015-09-28 新日鐵住金株式会社 板厚１５ｍｍ以上の電縫鋼管用熱延鋼板

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006132441A1 (fr) * 2005-06-10 2006-12-14 Nippon Steel Corporation Tuyau de puits de pétrole pour utilisation en tube extensible d’une excellente robustesse après expansion du tube et procédé de fabrication idoine
JP2010001566A (ja) * 2008-05-19 2010-01-07 Nippon Steel Corp 低降伏比高強度電縫鋼管及びその製造方法
JP2015168864A (ja) * 2014-03-07 2015-09-28 新日鐵住金株式会社 板厚１５ｍｍ以上の電縫鋼管用熱延鋼板

Similar Documents

Publication Publication Date Title
JP5857400B2 (ja) 高圧縮強度ラインパイプ用溶接鋼管及びその製造方法
JP6288390B1 (ja) ラインパイプ用アズロール電縫鋼管
JP4833835B2 (ja) バウシンガー効果の発現が小さい鋼管およびその製造方法
JP5223379B2 (ja) 低温靭性に優れるスパイラルパイプ用高強度熱延鋼板およびその製造方法
JP5561120B2 (ja) 高圧縮強度高靭性ラインパイプ用溶接鋼管及びその製造方法
RU2534566C1 (ru) Толстостенная сварная стальная труба с превосходной низкотемпературной ударной вязкостью, способ изготовления толстостенной сварной стальной трубы с превосходной низкотемпературной ударной вязкостью, и стальная пластина для изготовления толстостенной сварной стальной трубы
WO2015030210A1 (fr) Tôle d'acier pour tube de canalisation haute résistance à paroi épaisse présentant d'exceptionnelles propriétés de résistance au vieillissement, de résistance aux chocs, et une ductilité à faible température, et tube de canalisation
WO2011065582A1 (fr) Tuyau d'acier soudé pour tube de canalisation présentant une résistance à la compression supérieure et une excellente résistance à l'acidité, et procédé de production de celui-ci
JP5782827B2 (ja) 高圧縮強度耐サワーラインパイプ用鋼管及びその製造方法
JP6213703B1 (ja) ラインパイプ用電縫鋼管
JP4837807B2 (ja) 高強度溶接鋼管及びその製造方法
JPWO2019058422A1 (ja) 鋼管及び鋼板
WO2018235244A1 (fr) Tube d'acier soudé par résistance électrique de laminage pour tuyau de canalisation, et tôle d'acier laminée à chaud
JP5768603B2 (ja) 高一様伸び特性を備え、かつ溶接部低温靱性に優れた高強度溶接鋼管、およびその製造方法
WO2016152170A1 (fr) Tôle d'acier épaisse pour tuyau de construction, procédé pour la production de tôle d'acier épaisse pour tuyau de construction et tuyau de construction
WO2016185741A1 (fr) Tuyau en acier soudé par résistance électrique à haute résistance, procédé pour la production de tôle d'acier pour tuyau en acier soudé par résistance électrique à haute résistance et procédé pour la production de tuyau en acier soudé par résistance électrique à haute résistance
WO2018008194A1 (fr) Tuyau en acier électrosoudé pour tuyau de canalisation
JP5803270B2 (ja) 耐圧潰性に優れた高強度耐サワーラインパイプ及びその製造方法
WO2015151468A1 (fr) Matériau en acier pour tuyaux de canalisation hautement déformables ayant des caractéristiques de vieillissement après déformation et caractéristiques anti-hic supérieures, procédé de fabrication de ce dernier et tuyau en acier soudé
JP4949541B2 (ja) 二相組織油井鋼管及びその製造方法
WO2018066249A1 (fr) Tuyau en acier soudé par résistance électrique destiné à une poutre de torsion
JP7216902B2 (ja) 油井用電縫鋼管およびその製造方法
JP7155703B2 (ja) ラインパイプ用厚鋼板およびその製造方法
JP5786351B2 (ja) 耐コラプス性能の優れたラインパイプ用鋼管
JP6213702B1 (ja) ラインパイプ用電縫鋼管

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18921595

Country of ref document: EP

Kind code of ref document: A1

WA Withdrawal of international application
NENP Non-entry into the national phase

Ref country code: DE