WO2012141220A1 - Plaque d'acier à haute résistance et tuyau d'acier à haute résistance ayant une excellente déformabilité et une excellente ténacité à basse température, et leurs procédés de fabrication - Google Patents

Plaque d'acier à haute résistance et tuyau d'acier à haute résistance ayant une excellente déformabilité et une excellente ténacité à basse température, et leurs procédés de fabrication Download PDF

Info

Publication number
WO2012141220A1
WO2012141220A1 PCT/JP2012/059917 JP2012059917W WO2012141220A1 WO 2012141220 A1 WO2012141220 A1 WO 2012141220A1 JP 2012059917 W JP2012059917 W JP 2012059917W WO 2012141220 A1 WO2012141220 A1 WO 2012141220A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
temperature
strength steel
plane
low
Prior art date
Application number
PCT/JP2012/059917
Other languages
English (en)
Japanese (ja)
Inventor
坂本　真也
原　卓也
Original Assignee
新日本製鐵株式会社
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 新日本製鐵株式会社 filed Critical 新日本製鐵株式会社
Priority to CN201280005710.2A priority Critical patent/CN103328669B/zh
Priority to KR1020137015161A priority patent/KR101531361B1/ko
Priority to BR112013026065-3A priority patent/BR112013026065B1/pt
Priority to JP2013509948A priority patent/JP5413537B2/ja
Publication of WO2012141220A1 publication Critical patent/WO2012141220A1/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
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling
    • 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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • 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
    • C21D2201/00—Treatment for obtaining particular effects
    • C21D2201/05—Grain orientation
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/008—Martensite

Definitions

  • the present invention is suitably used as a line pipe for transportation of natural gas, crude oil and the like, and in particular, a high-strength steel plate and a high-strength steel pipe excellent in deformation performance and low-temperature toughness with a large deformation tolerance against ground fluctuation and the like, and production thereof Regarding the method.
  • line pipes have become increasingly important as a long-distance transportation method for natural gas and crude oil.
  • Line pipes are laid in various environments. For example, ground pipes are frozen in summer and winter in frozen land belts, are subject to external pressure due to ocean currents on the seabed, and are subject to ground deformation due to earthquakes. Under such an environment, the line pipe may bend and displace due to ground fluctuation or the like, and therefore, a steel pipe excellent in deformation performance that hardly causes buckling or the like even when the line pipe is deformed is desired.
  • the technology that has been proposed in the past is a technology that focuses on the work hardening index and yield ratio to improve the deformation performance of steel plates and steel pipes used in line pipes.
  • line pipes used in cold regions such as frozen land zones are required to have excellent low-temperature toughness, but for technology to obtain steel plates and steel pipes that are excellent in deformation performance and low-temperature toughness. Sufficient consideration has not been made.
  • the present invention has been devised in view of the above-described problems, and is capable of suppressing the amount of reduction in thickness during deformation, a high-strength steel plate and a high-strength steel pipe excellent in deformation performance and low-temperature toughness, and these It is an object to provide a manufacturing method.
  • the present inventors diligently studied to solve the above problems. As a result, it has been found that the deformation performance of steel plates and steel pipes used in pipelines and the like can be improved by paying attention to the Rankford value.
  • the present inventors have intensively studied to obtain a high-strength steel plate and a high-strength steel pipe excellent in deformation performance and low-temperature toughness.
  • the size of the effective crystal grain size should be optimized while optimizing the amount of texture having a predetermined crystal orientation.
  • the present inventors have further studied, and in order to optimize the amount of texture having a predetermined crystal orientation, it is particularly effective to control various production conditions including the reduction ratio during hot rolling. In particular, it has been found that the rolling reduction per rolling pass in the temperature range above the recrystallization temperature is very important.
  • the present invention has been made as a result of studies based on the above findings, and the gist thereof is as follows.
  • C, Mn, Ni, Cu, Cr, Mo, V, Si, and B are contents in mass% of each element.
  • V 0.010 to 0.100%
  • Ni 1.0% or less
  • Cu 1.0% or less
  • Cr 1.0% or less
  • Mo 1.0%
  • B 0.0001 to 0.0020%
  • Ca 0.0040% or less
  • Mg 0.0010% or less
  • REM 0.005% or less
  • a high-strength steel pipe excellent in deformation performance and low-temperature toughness characterized by comprising the steel plate of any one of (1) to (3) above.
  • C, Mn, Ni, Cu, Cr, Mo, V, Si, and B are contents in mass% of each element.
  • the steel slab further comprises, in mass%, V: 0.010 to 0.100%, Ni: 1.0% or less, Cu: 1.0% or less, Cr: 1.0% or less, Mo : 1.0% or less, B: 0.0001 to 0.0020%, Ca: 0.0040% or less, Mg: 0.0010% or less, REM: 0.005%, containing one or more elements selected from the following: (6)
  • a method for producing a high-strength steel pipe excellent in deformation performance and low-temperature toughness characterized in that a steel plate obtained by the production method of (5) or (6) is formed into a tubular shape and a butt portion is welded.
  • the present invention it is possible to obtain a high-strength steel plate and a high-strength steel pipe excellent in deformation performance and low-temperature toughness that can suppress a decrease in thickness during deformation.
  • C is an element necessary for securing the strength of steel. If the C content is less than 0.03%, the strength of the final product is insufficient. When the C content is more than 0.08%, the low temperature toughness of the base material and HAZ is remarkably lowered. Therefore, the C content is 0.03 to 0.08%.
  • Si is an element that acts as a deoxidizer and contributes to the improvement of strength. If the Si content is less than 0.01%, the strength of the final product may be insufficient. If the Si amount is more than 0.50%, the HAZ toughness is remarkably lowered. Therefore, the Si amount is set to 0.01 to 0.50%.
  • Mn is an element that contributes to improving the strength of steel. If the Mn content is less than 1.50%, the strength of the final product may be insufficient. When the amount of Mn exceeds 2.50%, the low temperature toughness of the base material and the HAZ is remarkably lowered. Therefore, the Mn content is 1.50-2.50%. Preferably, it is 1.50 to 2.00%.
  • Al is an element that contributes to refinement of the metal structure as a deoxidizing element. If the Al content is less than 0.001%, this effect cannot be sufficiently obtained. If the Al content exceeds 0.080%, Al-based non-metallic inclusions increase in the steel and the cleanliness of the steel deteriorates. Therefore, the amount of Al is limited to 0.080% or less. A preferred range is 0.001 to 0.050% or less.
  • Ti is an element that precipitates as TiN in the steel to suppress the coarsening of the austenite grains of the HAZ during reheating of the slab and refine the metal structure and improve the low temperature toughness of the base material and the HAZ.
  • the Ti content is less than 0.005%, this effect cannot be sufficiently obtained.
  • the Ti content exceeds 0.030%, the low temperature toughness deteriorates due to the coarsening of TiN and precipitation hardening by TiC. Therefore, the Ti amount is set to 0.005 to 0.030%.
  • Nb has the effect of suppressing the recrystallization of austenite during hot rolling to refine the structure and improving the low temperature toughness of the base material and HAZ, but this effect is achieved when the Nb content is less than 0.010%. Is not enough. On the other hand, if the Nb content exceeds 0.050%, the HAZ toughness and on-site weldability are adversely affected. Therefore, the Nb content is 0.010 to 0.050%.
  • P is an impurity inevitably contained in the steel, and the low temperature toughness of the base metal and HAZ deteriorates by causing grain boundary segregation and center segregation, but if the amount of P is 0.015% or less This is an acceptable range for low temperature toughness. Therefore, the P content is limited to 0.015% or less.
  • S is an impurity inevitably contained in the steel, and ductility and toughness are reduced by producing sulfides that are stretched by hot rolling in the steel, but the amount of S is 0.0050% or less. If it exists, it becomes an allowable range for ductility and toughness. Therefore, the amount of S is limited to 0.0050% or less.
  • N is an element that improves the low temperature toughness of the base material and the HAZ by precipitating as TiN in the steel, thereby suppressing the coarsening of the austenite grains of the HAZ during reheating of the slab. If the N content is less than 0.0010%, this effect cannot be sufficiently obtained. If the N content exceeds 0.0060%, the toughness decreases due to an increase in the solid solution N content. Therefore, the N content is 0.0010 to 0.0060%.
  • the carbon equivalent Ceq represented by the following formula (A) calculated from the content in terms of mass% of C, Mn, Ni, Cu, Cr, Mo, V is 0.35 to 0. .50%.
  • the carbon equivalent Ceq is a value that serves as an index of hardenability.
  • the Ceq value is less than 0.35%, the target tensile strength of 565 MPa or more cannot be obtained. If the Ceq value is more than 0.50%, MA (Martensite-Austenite Constituent: a mixture of martensite and austenite) that deteriorates toughness becomes prominent, and the toughness deteriorates.
  • MA Martensite-Austenite Constituent: a mixture of martensite and austenite
  • Pcm represented by the following numerical formula (B) calculated from the content in the mass% of C, Si, Mn, Cu, Cr, Ni, Mo, V, and B is 0.15. ⁇ 0.25%. Pcm is a value that serves as an index of weldability.
  • the element not contained in the steel is calculated as 0.
  • the balance of the steel sheet and steel pipe according to the present invention is composed of Fe and inevitable impurities.
  • the steel plate and the steel pipe according to the present invention include one or more elements selected from V, Ni, Cu, Cr, Mo, B, Ca, Mg, and REM, as necessary. It may be further contained in a numerical range as described in (1). Even if these elements are contained in the following ranges, the X-ray random intensity ratio and the Rankford value in the steel plate and steel pipe are within the ranges specified in the present invention.
  • V has almost the same effect as Nb, but the effect is weaker than Nb. Moreover, it has the effect which suppresses softening of a welding part. If the amount of V is less than 0.010%, the effect of improving the low temperature toughness of the base metal and HAZ and suppressing the softening of the welded portion will be insufficient. If the amount of V exceeds 0.100%, it adversely affects the toughness of HAZ and on-site weldability. Therefore, the V amount is 0.010 to 0.100%.
  • Ni, Cu, Cr, and Mo are elements that increase the hardenability and contribute to increasing the strength of steel.
  • the content is too large, the toughness of the HAZ and the field weldability are lowered in addition to the reduction in economic efficiency. Therefore, Ni, Cu, Cr, and Mo each have a content of 1.0% or less.
  • B is an element that enhances hardenability and contributes to high strength of steel. If the amount of B is less than 0.0001%, this effect cannot be sufficiently obtained. If the amount of B exceeds 0.0020%, the toughness of HAZ and on-site weldability will deteriorate. Therefore, the B amount is set to 0.0001 to 0.0020%.
  • Ca and REM are elements that control the form of sulfide and contribute to the improvement of low temperature toughness. If the Ca content exceeds 0.0040% and the REM content exceeds 0.005%, a large amount of CaO-CaS or REM-CaS precipitates to form large clusters and large inclusions, which impairs the cleanliness of the steel. Also, there is a risk of adversely affecting on-site weldability. Therefore, the Ca content is 0.0040% or less, and the REM content is 0.005% or less.
  • Mg is an element that disperses and precipitates as a fine oxide and contributes to the improvement of low temperature toughness by suppressing the coarsening of the HAZ grain size. If the Mg content is more than 0.0010%, the toughness deteriorates due to the coarsening of the oxide. Therefore, the Mg content is 0.0010% or less.
  • the metal structure needs to be composed of a composite structure of soft ferrite and one or two of hard bainite and martensite in order to improve work hardening characteristics.
  • the metal structure needs to have an effective crystal grain size of 20 ⁇ m or less at the center of thickness. This is because the low temperature toughness deteriorates when the effective crystal grain size exceeds 20 ⁇ m.
  • the effective crystal grain size is the crystal grain size at the equivalent circle diameter of the part surrounded by the boundary of the structure with an orientation difference of 15 ° or less, as measured by the EBSP (Electron Backscatter Diffraction Pattern) method. Means.
  • the texture needs to satisfy the conditions as described below for the X-ray random intensity ratio in order to obtain preferable Rankford values for steel plates and steel pipes.
  • attention is paid to the Rankford value rD in the 45 ° direction with respect to the rolling direction of the steel sheet and the Rankford value rC in the sheet width direction.
  • the crystal orientations described below all refer to planes parallel to the plate surface.
  • the X-ray random intensity ratio is a numerical value representing the degree of integration of crystal planes having respective orientations, and indicates the ratio of X diffraction intensities of crystal planes having respective orientations to a random standard sample having no texture.
  • the texture having the ⁇ 111 ⁇ plane crystal orientation is preferably developed as much as possible because rC and rD can be increased as the texture grows.
  • the X-ray random intensity ratio of the ⁇ 111 ⁇ plane needs to be 0.5 or more. If the X-ray random intensity ratio of the ⁇ 111 ⁇ plane exceeds 5.0, the target value may not be obtained for the X-ray random intensity ratio of other crystal orientations.
  • the intensity ratio is 5.0 or less.
  • the texture having the ⁇ 554 ⁇ plane crystal orientation can increase the rC as it develops, so it is preferable that it develop as much as possible.
  • the X-ray random intensity ratio of the ⁇ 554 ⁇ plane needs to be 1.0 or more. Further, if the X-ray random intensity ratio of the ⁇ 554 ⁇ plane is more than 3.0, a target value may not be obtained for the X-ray random intensity ratio of other crystal orientations.
  • the line random intensity ratio is 3.0 or less.
  • the texture having the ⁇ 100 ⁇ plane crystal orientation becomes the cause of lowering rC and rD as it grows, it is preferable that the development is suppressed as much as possible.
  • the X-ray random intensity ratio of the ⁇ 100 ⁇ plane needs to be 3.0 or less.
  • the texture having the ⁇ 112 ⁇ plane and ⁇ 223 ⁇ plane crystal orientation is developed as much as possible, because the rD can be increased as it grows.
  • the X-ray random intensity ratio of each of the ⁇ 112 ⁇ plane and the ⁇ 223 ⁇ plane needs to be 0.5 or more. If the X-ray random intensity ratio of each of the ⁇ 112 ⁇ plane and the ⁇ 223 ⁇ plane exceeds 4.0, the target value may not be obtained for the X-ray random intensity ratio of other crystal orientations.
  • the X-ray random intensity ratio between the ⁇ 223 ⁇ plane and the ⁇ 223 ⁇ plane is 4.0 or less.
  • a measured value measured by X-ray diffraction at the center of thickness is used. This is because the texture that can increase the rC and rD of the ⁇ 111 ⁇ plane, etc. is easy to develop in the thick surface layer part and difficult to develop in the central thickness part, so the X-ray random intensity ratio in the thick central part.
  • the evaluation object it is possible to exhibit a deformation performance of a certain level or more in the entire thickness direction.
  • the steel sheet has a thickness of 25 mm or more and a tensile strength of 565 MPa or more (API standard of X70 or more from the viewpoint of preventing breakage due to internal pressure when used as a line pipe while ensuring the strength required as a final product. Grade).
  • the deformation performance improves as the Rankford value rD in the 45 ° direction and the Rankford value rC in the sheet width direction increase with respect to the rolling direction of the steel sheet.
  • rD and rC are preferably 1.0 or more, more preferably 1.1 or more.
  • a steel piece is obtained from the molten steel obtained by a known casting method such as continuous casting.
  • the obtained steel slab is heated to a temperature of 1000 to 1150 ° C. If the heating temperature is less than 1000 ° C., sufficient recrystallization of austenite cannot be achieved, and sufficiently high low temperature toughness cannot be obtained. When the heating temperature is higher than 1150 ° C., the austenite grains are coarsened, the effective crystal grain size is increased, and the low temperature toughness is lowered.
  • the reduction rate per pass that is, the value of the cumulative reduction rate / pass number
  • the heating temperature is 1000 ° C. or more and less than 1050 ° C.
  • rolling is performed at 10 to 15%, and the cumulative rolling reduction is 35% or higher. If the cumulative rolling reduction is less than 35%, the austenite grain size cannot be sufficiently reduced by recrystallization, the effective crystal grain size increases, and the low temperature toughness decreases.
  • the rolling reduction per pass is particularly important in obtaining the target texture of crystal orientation.
  • the rolling reduction per pass has not been increased due to equipment restrictions and the like.
  • the rolling reduction per pass needs to be in the above range. If the rolling reduction per pass is out of the above range, the target texture distribution cannot be obtained.
  • the reduction rate of individual paths may be outside the above range due to reasons such as the pass schedule, but it is preferable that the reduction rate is in the above range in passes that are more than half of the number of passes. It is more preferable that the above range be in the pass.
  • water cooling is performed with an Ar 3 transformation point of ⁇ 50 ° C. or more and lower than the Ar 3 transformation point as a cooling start temperature and a temperature range of 200 to 500 ° C. as a cooling end temperature.
  • the cooling start temperature is less than Ar 3 transformation point ⁇ 50 ° C.
  • the formation of ferrite is promoted and the target strength cannot be obtained.
  • the cooling start temperature is equal to or higher than the Ar 3 transformation point, the development of the texture of each of the ⁇ 112 ⁇ plane and the ⁇ 223 ⁇ plane is suppressed, and the target X-ray random intensity ratio cannot be obtained. Decreases.
  • the cooling rate is not particularly limited, but is about 1 to 10 ° C./s.
  • the Ar 3 transformation point is obtained from the following mathematical formula (C).
  • C, Si, etc. in the following mathematical formula (C) mean the content of each element in mass% in steel.
  • Ar 3 868-396 ⁇ C + 24.6 ⁇ Si-69.1 ⁇ Mn-36.1 ⁇ Ni-20.7 ⁇ Cu-24.8 ⁇ Cr + 29.6 ⁇ Mo (C)
  • the steel plate thus manufactured is further formed into a tubular shape, and a steel pipe is obtained by joining the butted portions.
  • a known UOE method, a bending roll method, or the like is used as a tube forming method for forming the steel sheet into a tubular shape, and arc welding, laser welding, or the like is used as a welding method for the butt portion.
  • the molten steel having the composition of each steel type A to F shown in Table 1 below was melted in a converter and made into a steel slab by continuous casting.
  • the obtained steel slab was hot-rolled and cooled under the conditions shown in Table 2 below. Nos. 1-5 and 8-15, and No. 1 in which the steel plate was formed into a tubular shape and the butt portion was joined. 6-7 steel pipes were obtained. No. The diameter of the 6-7 steel pipe is 48 inches (1219.2 mm).
  • Tensile strength was measured by cutting out a JIS No. 5 plate-like test piece whose longitudinal direction was parallel to the rolling direction from the obtained steel sheet, and performing a tensile test based on the method described in JIS Z2241 using this test piece. Further, the tensile strength was also obtained for the grades in the API standard. For the steel pipe, the tensile strength was measured with a full thickness test piece in the longitudinal direction of the steel pipe based on the API standard.
  • the metal structure was observed with an optical microscope. Effective crystal grain size is measured by the EBSP method, the boundary of the structure having an orientation difference of 15 ° or more is regarded as a grain boundary, the area inside one crystal is obtained, and the area converted to the equivalent circle diameter is effective. The crystal grain size was evaluated.
  • the X-ray random strength ratio was obtained by cutting a test piece of 10 mm in the rolling direction ⁇ 10 mm in the plate width direction from the obtained steel plate, polishing the test piece to the vicinity of the thickness center by mechanical polishing, and polishing it to a mirror surface by buffing, The strain was removed by electrolytic polishing or the like, and at the same time, the thickness center layer was adjusted to be a measurement surface, and evaluation was performed by measuring the diffraction intensity of each crystal orientation by X-ray diffraction.
  • the Rankford value is obtained by cutting out a JIS No. 5 plate-shaped test piece from the obtained steel plate, a test piece whose longitudinal direction is parallel to the rolling direction, a test piece parallel to the 45 ° direction with respect to the rolling direction, and the plate width direction. Parallel test specimens were manufactured, and tensile tests based on the method described in JISZ2241 were performed using these test specimens. When the specimen was given a uniaxial tensile strain of 3%, the width strain of each test specimen and Each rankford value rC, rD, rL was evaluated from the thickness strain ratio. rL is the Rankford value in the rolling direction.
  • Manufacturing No. Nos. 1 to 7 are invention examples. 1 to 5 are steel plates; 6 to 7 are examples of steel pipes. In all of these, the composition, metal structure, effective crystal grain size, X-ray random strength ratio, wall thickness, and tensile strength satisfy the conditions of the present invention, the rD value is 1.0 or more, and the rC value is 1. A high-strength steel sheet excellent in low-temperature toughness with a Charpy absorbed energy of 200 J or more is obtained.
  • the metal structure, effective crystal grain size, X-ray random strength ratio, and tensile strength satisfy the conditions of the present invention. What has been obtained.
  • FIG. 1 shows an example of a structure photograph at the thickness center of the steel sheet of the invention.
  • the photograph in FIG. Two In the structure photograph, a white portion having no fine structure inside is ferrite, and a portion other than ferrite, which is gray as a whole and has a fine structure inside, is bainite or martensite.
  • Manufacturing No. 8 to 15 are comparative examples.
  • Production No. No. 8 is an example in which the effective crystal grain size is large because the heating temperature is high, and the low temperature toughness is deteriorated.
  • Manufacturing No. No. 9 has a low rolling reduction per pass in a temperature range equal to or higher than the recrystallization temperature, so the target texture distribution was not obtained, and the rD and rC values, which are indicators of deformation characteristics, deteriorated. It is an example.
  • Manufacturing No. No. 10 is an example in which the cumulative reduction rate in the temperature range above the recrystallization temperature is low, so that the austenite grain size cannot be sufficiently reduced by recrystallization, the effective crystal grain size is increased, and the low temperature toughness is deteriorated. is there.
  • Production No. No. 11 is an example in which the development of the texture of the ⁇ 554 ⁇ plane is suppressed and the rC value is deteriorated because the cumulative rolling reduction in the temperature range from the Ar 3 transformation point to the recrystallization temperature is low.
  • Manufacturing No. No. 12 is an example in which, since the cooling start temperature is high, the development of the texture of each of the ⁇ 112 ⁇ plane and the ⁇ 223 ⁇ plane is suppressed, and the rD value is deteriorated.
  • Manufacturing No. No. 13 is an example in which the strength is lowered because the cooling end temperature is high.
  • Manufacturing No. No. 14 is an example in which the strength, the rD value, and the rC value are deteriorated because both Ceq and Pcm are low and the rolling reduction per pass in the temperature range equal to or higher than the recrystallization temperature is low.
  • Manufacturing No. No. 15 is an example in which both Ceq and Pcm are high, the effective crystal grain size is large because the heating temperature is high, and the toughness is lowered by increasing the strength.

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)

Abstract

L'invention concerne une plaque d'acier à haute résistance et un tuyau d'acier à haute résistance ayant une excellente déformabilité et une excellente ténacité à basse température, par lesquels il est possible de supprimer la diminution d'épaisseur pendant une déformation, et leurs procédés de fabrication. La plaque d'acier à haute résistance est caractérisée en ce qu'elle comprend une composition à l'intérieur d'une plage de valeurs numériques prédéterminée, en ce qu'elle comprend une structure complexe présentant un ou plusieurs types de ferrite, bainite et martensite ; le diamètre effectif de particule cristalline dans la partie centrale de l'épaisseur est de 20 µm ou moins ; le rapport d'intensité aléatoire de rayons X d'un plan {111} parallèle à la surface de la plaque dans la partie centrale de l'épaisseur est de 0,5-5,0 ; le rapport d'intensité aléatoire des rayons X d'un plan {554} est de 1,0-3,0 ; le rapport d'intensité aléatoire des rayons X d'un plan {100} est de 3,0 ou moins ; les rapports d'intensité aléatoire des rayons X d'un plan {112} et d'un plan {223} sont tous les deux de 0,5 - 4,0 ; l'épaisseur est égale ou supérieure à 25 mm ; et la résistance à la traction est égale ou supérieure à 565 MPa.
PCT/JP2012/059917 2011-04-12 2012-04-11 Plaque d'acier à haute résistance et tuyau d'acier à haute résistance ayant une excellente déformabilité et une excellente ténacité à basse température, et leurs procédés de fabrication WO2012141220A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CN201280005710.2A CN103328669B (zh) 2011-04-12 2012-04-11 变形性能和低温韧性优良的高强度钢板、高强度钢管以及它们的制造方法
KR1020137015161A KR101531361B1 (ko) 2011-04-12 2012-04-11 변형 성능 및 저온 인성이 우수한 고강도 강판 및 고강도 강관 및 이들의 제조 방법
BR112013026065-3A BR112013026065B1 (pt) 2011-04-12 2012-04-11 Chapa de aço de alta resistência e tubo de aço de alta resintência excelentes em capacidade de deformação e tenacidade a baixa temperatura e método de produção dos mesmos
JP2013509948A JP5413537B2 (ja) 2011-04-12 2012-04-11 変形性能及び低温靭性に優れた高強度鋼板及び高強度鋼管並びにこれらの製造方法

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011088564 2011-04-12
JP2011-088564 2011-04-12

Publications (1)

Publication Number Publication Date
WO2012141220A1 true WO2012141220A1 (fr) 2012-10-18

Family

ID=47009387

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/059917 WO2012141220A1 (fr) 2011-04-12 2012-04-11 Plaque d'acier à haute résistance et tuyau d'acier à haute résistance ayant une excellente déformabilité et une excellente ténacité à basse température, et leurs procédés de fabrication

Country Status (5)

Country Link
JP (1) JP5413537B2 (fr)
KR (1) KR101531361B1 (fr)
CN (1) CN103328669B (fr)
BR (1) BR112013026065B1 (fr)
WO (1) WO2012141220A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014237964A (ja) * 2013-06-07 2014-12-18 新日鐵住金株式会社 壁パネル
WO2016045266A1 (fr) * 2014-09-26 2016-03-31 宝山钢铁股份有限公司 Acier à haute résistance pour laminage à chaud à haute ténacité présentant une limite d'élasticité de 800 mpa et son procédé de préparation
EP3239327A4 (fr) * 2014-12-24 2017-11-22 Posco Matériau d'acier haute résistance pour récipient sous pression ayant une ténacité remarquable après traitement thermique post-soudure (pwht), et son procédé de production

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101899689B1 (ko) 2016-12-23 2018-09-17 주식회사 포스코 길이방향 균일 연신율이 우수한 용접강관용 강재, 이의 제조방법 및 이를 이용한 강관
KR101999027B1 (ko) * 2017-12-26 2019-07-10 주식회사 포스코 수소유기균열 저항성이 우수한 압력용기용 강재 및 그 제조방법
CN110317994B (zh) * 2018-03-30 2021-12-17 宝山钢铁股份有限公司 一种高热输入焊接用超高强度钢及其制造方法
CN109355549B (zh) * 2018-12-11 2020-10-02 东北大学 一种具有高强度和优异低温韧性的钢板及其制造方法
KR102307903B1 (ko) * 2019-11-04 2021-09-30 주식회사 포스코 저온 충격인성이 우수한 고강도 강재 및 그 제조방법
CN111334716B (zh) * 2020-03-25 2021-04-13 江西理工大学 一种含铬钛硼的低碳高强深冲钢及其制备方法和应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08209240A (ja) * 1995-02-02 1996-08-13 Nippon Steel Corp 耐ｃｏ２ 腐食性および低温靱性の優れたラインパイプ用鋼板の製造方法
JP2003293039A (ja) * 2002-04-01 2003-10-15 Nippon Steel Corp 粗大結晶粒の含有を抑制し、低温靱性に優れた高強度鋼板および鋼管の製造方法
JP2004225132A (ja) * 2003-01-24 2004-08-12 Nippon Steel Corp 深絞り性に優れた高強度冷延鋼板及びめっき鋼板、加工性に優れた鋼管、並びに、それらの製造方法
JP2009179832A (ja) * 2008-01-29 2009-08-13 Jfe Steel Corp 角筒絞り成形性と形状凍結性に優れた高強度冷延鋼板およびその製造方法ならびに製品形状に優れた自動車用部品
JP2009263718A (ja) * 2008-04-24 2009-11-12 Nippon Steel Corp 穴広げ性に優れた熱延鋼板及びその製造方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1144893C (zh) * 2000-02-28 2004-04-07 新日本制铁株式会社 成形性优良的钢管及制造这种钢管的方法
WO2006106591A1 (fr) * 2005-04-04 2006-10-12 Nippon Steel Corporation Tole d’acier tres resistante et tuyau d’acier soude tres resistant ayant une performance de cassure ductile excellente et procede pour les fabriquer
KR100833035B1 (ko) * 2006-12-20 2008-05-27 주식회사 포스코 변형능이 우수한 고강도 고인성 라인파이프용 강판 및 그제조방법
KR100951296B1 (ko) * 2007-12-04 2010-04-02 주식회사 포스코 저온인성이 우수한 고강도 라인파이프용 강판 및 그제조방법
KR100979007B1 (ko) * 2007-12-27 2010-08-30 주식회사 포스코 극저온 인성이 우수한 초고강도 라인파이프용 강판 및 그제조방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08209240A (ja) * 1995-02-02 1996-08-13 Nippon Steel Corp 耐ｃｏ２ 腐食性および低温靱性の優れたラインパイプ用鋼板の製造方法
JP2003293039A (ja) * 2002-04-01 2003-10-15 Nippon Steel Corp 粗大結晶粒の含有を抑制し、低温靱性に優れた高強度鋼板および鋼管の製造方法
JP2004225132A (ja) * 2003-01-24 2004-08-12 Nippon Steel Corp 深絞り性に優れた高強度冷延鋼板及びめっき鋼板、加工性に優れた鋼管、並びに、それらの製造方法
JP2009179832A (ja) * 2008-01-29 2009-08-13 Jfe Steel Corp 角筒絞り成形性と形状凍結性に優れた高強度冷延鋼板およびその製造方法ならびに製品形状に優れた自動車用部品
JP2009263718A (ja) * 2008-04-24 2009-11-12 Nippon Steel Corp 穴広げ性に優れた熱延鋼板及びその製造方法

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014237964A (ja) * 2013-06-07 2014-12-18 新日鐵住金株式会社 壁パネル
WO2016045266A1 (fr) * 2014-09-26 2016-03-31 宝山钢铁股份有限公司 Acier à haute résistance pour laminage à chaud à haute ténacité présentant une limite d'élasticité de 800 mpa et son procédé de préparation
US10378073B2 (en) 2014-09-26 2019-08-13 Baoshan Iron & Steel Co., Ltd. High-toughness hot-rolling high-strength steel with yield strength of 800 MPa, and preparation method thereof
RU2701237C2 (ru) * 2014-09-26 2019-09-25 Баошан Айрон Энд Стил Ко., Лтд. Высокопрочная горячекатаная сталь с высокой ударной прочностью и пределом текучести не менее 800 мпа и способ ее производства
EP3239327A4 (fr) * 2014-12-24 2017-11-22 Posco Matériau d'acier haute résistance pour récipient sous pression ayant une ténacité remarquable après traitement thermique post-soudure (pwht), et son procédé de production
US20190100818A1 (en) * 2014-12-24 2019-04-04 Posco High-strength steel plate for pressure vessel having excellent toughness after post weld heat treatment and manufacturing method thereof
US10604817B2 (en) 2014-12-24 2020-03-31 Posco High-strength steel plate for pressure vessel having excellent toughness after post weld heat treatment and manufacturing method thereof

Also Published As

Publication number Publication date
KR101531361B1 (ko) 2015-06-24
CN103328669A (zh) 2013-09-25
BR112013026065A2 (pt) 2019-08-20
CN103328669B (zh) 2015-03-11
JP5413537B2 (ja) 2014-02-12
KR20130114179A (ko) 2013-10-16
BR112013026065B1 (pt) 2020-05-26
JPWO2012141220A1 (ja) 2014-07-28

Similar Documents

Publication Publication Date Title
JP5413537B2 (ja) 変形性能及び低温靭性に優れた高強度鋼板及び高強度鋼管並びにこれらの製造方法
US8765269B2 (en) High strength steel pipe for low-temperature usage having excellent buckling resistance and toughness of welded heat affected zone and method for producing the same
JP5293903B1 (ja) 厚肉電縫鋼管及びその製造方法
JP5151008B2 (ja) 耐ｈｉｃ性および溶接部靱性優れる耐サワー高強度電縫鋼管用熱延鋼板およびその製造方法
JP5445720B1 (ja) アレスト性に優れた高強度厚鋼板
JP4969915B2 (ja) 耐歪時効性に優れた高強度ラインパイプ用鋼管及び高強度ラインパイプ用鋼板並びにそれらの製造方法
JP5048167B2 (ja) 低温靭性に優れた厚肉溶接鋼管および低温靭性に優れた厚肉溶接鋼管の製造方法、厚肉溶接鋼管製造用鋼板
JP5574059B2 (ja) 低温靭性に優れた高強度ｈ形鋼及びその製造方法
JP6193206B2 (ja) 耐サワー性、ｈａｚ靭性及びｈａｚ硬さに優れた鋼板およびラインパイプ用鋼管
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
JP4484123B2 (ja) 高強度かつ溶接熱影響部靭性に優れたクラッド鋼板用母材およびその製造方法
JP4837807B2 (ja) 高強度溶接鋼管及びその製造方法
JP6587041B1 (ja) ラインパイプ用電縫鋼管
JP5884201B2 (ja) 引張強さ５４０ＭＰａ以上の高強度ラインパイプ用熱延鋼板
JP2009068078A (ja) 靭性および疲労亀裂発生抑制特性に優れた溶接継手
WO2014175122A1 (fr) Poutre d'acier en forme de h et procédé de production de celle-ci
WO2016157863A1 (fr) Tôle d'acier à résistance et ténacité élevées et procédé pour la produire
JP2019116658A (ja) 疲労強度に優れた電縫鋼管およびその製造方法
JP2019116659A (ja) 疲労強度に優れた厚肉大径電縫鋼管およびその製造方法
JP2016216819A (ja) 厚鋼板及び溶接継手
WO2009119570A1 (fr) Tube d'acier uoe pour tubes de canalisation et son procédé de fabrication
JP2010222669A (ja) 熱間圧延ｔ形鋼およびその製造方法
JP7215332B2 (ja) 耐サワーラインパイプ用溶接鋼管の製造方法
JP6631353B2 (ja) 耐サワー鋼板及び耐サワー鋼管
JP2017155290A (ja) 耐サワー鋼板

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: 12771959

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2013509948

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20137015161

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12771959

Country of ref document: EP

Kind code of ref document: A1

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112013026065

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 112013026065

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20131009