KR20150074944A - High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof - Google Patents
High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof Download PDFInfo
- Publication number
- KR20150074944A KR20150074944A KR1020130163207A KR20130163207A KR20150074944A KR 20150074944 A KR20150074944 A KR 20150074944A KR 1020130163207 A KR1020130163207 A KR 1020130163207A KR 20130163207 A KR20130163207 A KR 20130163207A KR 20150074944 A KR20150074944 A KR 20150074944A
- Authority
- KR
- South Korea
- Prior art keywords
- less
- hot
- excluding
- rolling
- steel
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 86
- 239000010959 steel Substances 0.000 title claims abstract description 86
- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 title abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 7
- 238000005098 hot rolling Methods 0.000 claims description 18
- 238000001816 cooling Methods 0.000 claims description 11
- 229910000859 α-Fe Inorganic materials 0.000 claims description 11
- 238000005096 rolling process Methods 0.000 claims description 10
- 238000003303 reheating Methods 0.000 claims description 9
- 229910001562 pearlite Inorganic materials 0.000 claims description 7
- 238000004804 winding Methods 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 230000009467 reduction Effects 0.000 claims description 6
- 238000005496 tempering Methods 0.000 claims description 6
- 238000005304 joining Methods 0.000 claims description 2
- 239000011159 matrix material Substances 0.000 claims description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 11
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 11
- 239000001257 hydrogen Substances 0.000 abstract description 11
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- 239000011572 manganese Substances 0.000 description 15
- 238000005336 cracking Methods 0.000 description 12
- 239000000203 mixture Substances 0.000 description 9
- 239000010955 niobium Substances 0.000 description 9
- 239000011575 calcium Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 239000010936 titanium Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 238000005728 strengthening Methods 0.000 description 6
- 230000009466 transformation Effects 0.000 description 6
- 239000007789 gas Substances 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 229910052719 titanium Inorganic materials 0.000 description 5
- 238000003466 welding Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 238000005204 segregation Methods 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 239000010779 crude oil Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910004283 SiO 4 Inorganic materials 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000001636 atomic emission spectroscopy Methods 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000003763 resistance to breakage Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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 Steel (AREA)
Abstract
Description
본 발명은 유정관 등의 강관(파이프)에 사용되는 열연강판에 관한 것으로서, 보다 상세하게는 내HIC(hydrogen induced crack) 특성이 우수한 고강도 고인성 열연강판과 이로부터 제조된 강관에 관한 것이다.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-rolled steel sheet used for a steel pipe such as a tubular steel pipe, and more particularly to a high-strength and high-strength hot-rolled steel sheet having excellent HIC (hydrogen induced crack) characteristics and a steel pipe produced therefrom.
유정관 등으로 사용되는 강재는 고강도, 내외압 압괴강도, 인성, 내지연 파괴성 등이 요구된다. 한편, 최근 에너지 수요 증가에 따라, H2S(황화수소) 가스 함유량이 높은 원유 혹은 천연가스가 개발됨에 따라 H2S 가스에 의한 강재의 파손 저항성이 우수한 강재가 요구되고 있다. 또한 최근 에너지원으로써, 천연가스 요구가 증가되면서 고압의 천연가스 수송에 따라 라인파이프 강재에 높은 응력이 적용될 수 있으며, 이에 대해 내사워(sour) 특성이 우수한 강재가 요구되고 있다.
Steels used in fluidized tubes are required to have high strength, internal and external pressure strength, toughness, and delayed fracture resistance. On the other hand, as crude oil or natural gas having a high H 2 S (hydrogen sulfide) gas content has been developed due to recent increase in energy demand, a steel material excellent in resistance to breakage of steel material by H 2 S gas is required. Also, as a recent energy source, as the demand for natural gas increases, a high stress can be applied to the line pipe steel according to high-pressure natural gas transportation, and a steel material excellent in sour characteristics is required.
특히, H2S를 포함하는 가스 또는 원유 수송용 강재에서는 H2S에 의한 수소유기균열(HIC, Hydrogen induced crack)이 문제시되고 있는데, 강재와 H2S 분위기화의 부식반응에 의해 강재 표면에 발생되는 수소가 원자상태로 강중에 침입, 확산하여 분자화됨에 따라 강의 개재물이나 경한 2차상에 모인 수소 분자의 압력으로 인해 균열이 발생하는 것으로 알려져 있다.
Particularly, in the case of a gas containing H 2 S or a steel for transporting crude oil, a hydrogen organic crack (HIC) due to H 2 S is a problem. The corrosion reaction of the steel and H 2 S atmosphere It is known that cracks are generated due to the pressure of hydrogen molecules gathered on the inclusions of the steel or on the light secondary as the generated hydrogen enters the steel as an atomic state and diffuses and is molecularized.
또한, 극한지에서 원유 등을 채굴하는 경우, 우수한 인성을 갖는 강관이 요구되고 있다. 그러나, 종래에는 열처리 후 강도를 확보하기 위하여 합금원소를 과다하게 첨가하고, 열처리 조건을 최적화하지 못하여, 요구되는 강도를 만족할 수 있지만 극한지에서 요구되는 고인성 및 내HIC 특성의 문제를 완전히 해결하지 못하고 있다.
Further, in the case of mining crude oil or the like in an extreme ground, a steel pipe having excellent toughness is required. However, conventionally, in order to secure the strength after the heat treatment, the alloy element is excessively added and the heat treatment conditions are not optimized, so that the required strength can be satisfied, but the problems of the toughness and the HIC characteristic required in the extreme conditions are completely solved I can not.
본 발명의 일측면은 우수한 수소유기균열(HIC) 특성이 우수하고, 높은 강도와 인성을 확보할 수 있는 열연강판과 이를 이용하여 제조된 강관 및 이들을 제조하는 방법을 제공하고자 하는 것이다.
An aspect of the present invention is to provide a hot-rolled steel sheet excellent in hydrogen-organic cracking (HIC) characteristics, high strength and toughness, a steel pipe manufactured using the same, and a method for manufacturing the same.
본 발명의 일태양은 중량%로, C: 0.15~0.5%, Si: 0.2~0.5%, Mn: 1.0~2.5%, P: 0.02%이하(0은 제외), S: 0.01%이하(0은 제외), Ca: 0.001~0.006%, Al: 0.01~0.06%, N: 0.008%이하(0은 제외), Nb: 0.01~0.03%, Ti: 0.005~0.04%, B: 0.0001~0.003%, 나머지는 Fe 및 불가피한 불순물을 포함하고,An aspect of the present invention is a steel sheet comprising, by weight%, 0.15 to 0.5% of C, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% 0.001 to 0.006% of Ca, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), Nb of 0.01 to 0.03%, Ti of 0.005 to 0.04%, B of 0.0001 to 0.003% Comprises Fe and unavoidable impurities,
상기 C 및 Mn은 {(C/12)+(Mn/55)}*100 ≤ 4.6 을 만족하는 내HIC 특성이 우수한 고강도 고인성 열연강판을 제공한다.
The present invention provides a high strength and high toughness hot-rolled steel sheet excellent in HIC characteristics satisfying C and Mn satisfying {(C / 12) + (Mn / 55)} * 100? 4.6.
본 발명의 또 다른 일태양은 상기 조성 및 관계식을 만족하는 강 슬라브를 준비하는 단계;According to another aspect of the present invention, there is provided a method of manufacturing a steel slab, comprising the steps of: preparing a steel slab satisfying the above composition and relationship;
상기 강 슬라브를 재가열하는 단계;Reheating the steel slab;
재가열된 강 슬라브를 열간압연하고, Ar3 이상의 마무리 압연온도에서 열간압연하는 단계; 및Hot-rolling the reheated steel slab and hot rolling at a finishing rolling temperature of Ar3 or higher; And
열간압연 후 냉각하고, 480~680℃의 온도에서 권취하는 단계를 포함하는 내HIC 특성이 우수한 고강도 고인성 열연강판의 제조방법을 제공한다.
Rolling after hot rolling, and winding at a temperature of 480 to 680 캜. The present invention also provides a method of manufacturing a high strength and high toughness hot rolled steel sheet excellent in HIC characteristics.
본 발명의 또 다른 일태양은 상기 조성 및 관계식을 만족하고, 항복강도가 580MPa 이상인 내HIC 특성이 우수한 고강도 고인성 강관을 제공한다.
Another aspect of the present invention provides a high strength and high strength steel pipe that satisfies the above composition and relationship and has excellent HIC characteristics with a yield strength of 580 MPa or more.
본 발명의 또 다른 일태양은 상기 조성 및 관계식을 만족하는 강 슬라브를 준비하는 단계;According to another aspect of the present invention, there is provided a method of manufacturing a steel slab, comprising the steps of: preparing a steel slab satisfying the above composition and relationship;
상기 강 슬라브를 재가열하는 단계;Reheating the steel slab;
재가열된 강 슬라브를 열간압연하고, Ar3 이상의 마무리 압연온도에서 열간압연하는 단계;Hot-rolling the reheated steel slab and hot rolling at a finishing rolling temperature of Ar3 or higher;
열간압연 후 냉각하고, 480~680℃의 온도에서 권취하여 열연강판을 제조하는 단계; Rolling after hot rolling and winding at a temperature of 480 to 680 캜 to produce a hot-rolled steel sheet;
상기 열연강판을 조관하여 강관을 제조하는 단계;Preparing a steel pipe for joining the hot-rolled steel sheet;
상기 제조된 강관을 900~950℃에서 오스테나이징 처리하고, 650~700℃에서 2~3분간 템퍼링 열처리하는 단계를 포함하는 내HIC 특성이 우수한 고강도 고인성 강관의 제조방법을 제공한다.
The present invention also provides a method of manufacturing a high strength and high strength steel pipe having excellent HIC characteristics including austenizing the steel pipe at 900 to 950 ° C. and tempering at 650 to 700 ° C. for 2 to 3 minutes.
본 발명에 의하면, 항복강도가 580MPa 이상이고, 0℃에서 충격에너지 값이 170J 이상이며, 내수소유기균열 저항성이 우수한 강재를 제공함으로서, 부식환경 및 극한지에서 유용하게 사용될 수 있는 강관의 제조가 가능하다.
According to the present invention, it is possible to provide a steel material having a yield strength of 580 MPa or more, an impact energy value of 170 J or more at 0 캜, and excellent resistance to hydrogen-organic cracking, It is possible.
이하, 본 발명에 대해 상세히 설명한다. 먼저 본 발명의 조성에 대해 상세히 설명한다(이하, 중량%).Hereinafter, the present invention will be described in detail. First, the composition of the present invention will be described in detail (hereinafter,% by weight).
본 발명의 열연강판은 중량%로, C: 0.15~0.5%, Si: 0.2~0.5%, Mn: 1.0~2.5%, P: 0.02%이하(0은 제외), S: 0.01%이하(0은 제외), Ca: 0.001~0.006%, Al: 0.01~0.06%, N: 0.008%이하(0은 제외), Nb: 0.01~0.03%, Ti: 0.005~0.04%, B: 0.0001~0.003%, 나머지는 Fe 및 불가피한 불순물을 포함한다.
The hot-rolled steel sheet according to the present invention comprises 0.15 to 0.5% of C, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% or less of P (excluding 0) 0.001 to 0.006% of Ca, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), Nb of 0.01 to 0.03%, Ti of 0.005 to 0.04%, B of 0.0001 to 0.003% Includes Fe and unavoidable impurities.
탄소(C): 0.15~0.5%Carbon (C): 0.15-0.5%
상기 C는 강도, 인성 및 파이프라인 시공시의 원주 용접부 인성에 영향을 미치는 원소이다. 상기 C는 강재의 경화능을 증가시키는 원소로서 열간 마무리 압연 후 냉각시 페라이트 변태를 지연시켜 펄라이트 분율을 증가시킴으로써 항복강도뿐만 아니라 인장강도를 증가시킨다. 그 함량이 0.15% 미만인 경우 펄라이트 형성이 부족하여 본 발명에서 목표로 하는 강도를 확보할 수 없으며, 0.5%를 초과하는 경우 인성의 저하 및 전기저항 용접시 용접성의 저하를 초래하므로, 상기 C의 함량은 0.15~0.5%로 하는 것이 바람직하다.
C is an element that affects the strength, toughness, and toughness of a circumferential weld at the time of pipeline construction. C is an element for increasing the hardenability of steel, and increases the yield strength as well as the tensile strength by increasing the pearlite fraction by retarding the ferrite transformation upon cooling after hot rolling. If the content is less than 0.15%, the pearlite formation is insufficient and the desired strength can not be secured in the present invention. When the content exceeds 0.5%, the toughness is lowered and the weldability is lowered in the case of electric resistance welding, Is preferably 0.15 to 0.5%.
실리콘(Si): 0.2~0.5%Silicon (Si): 0.2 to 0.5%
Si은 페라이트 상중의 C 활동도를 증가시키고, 페라이트 안정화를 촉진하는 작용을 하며, 고용강화에 의한 강도확보에 기여한다. 또한, 상기 Si은 전기저항용접(ERW)시 Mn2SiO4 등의 저융점 산화물을 형성시키고 용접시에 산화물이 쉽게 배출되도록 한다. 그 함량이 0.2% 미만인 경우에는 제강상의 비용 문제가 발생하는 반면, 0.5%를 초과하는 경우에는 Mn2SiO4 이외에 고융점의 SiO2 산화물의 형성량이 많아지고, 전기저항용접시 용접부의 인성을 저하시킬 수 있다. 따라서, 상기 Si의 함량은 0.2~0.5%로 하는 것이 바람직하다.
Si increases C activity in the ferrite phase, promotes ferrite stabilization, and contributes to securing strength by solid solution strengthening. Also, the Si is to form a low-melting-point oxides such as Mn 2 SiO 4 when electric resistance welding (ERW) and an oxide easily discharged at the time of welding. If the content is less than 0.2%, a cost problem in steelmaking will arise. On the other hand, if the content exceeds 0.5%, the amount of SiO 2 oxide having a high melting point in addition to Mn 2 SiO 4 is increased and the toughness . Therefore, the content of Si is preferably 0.2 to 0.5%.
망간(Mn): 1.0~2.5%Manganese (Mn): 1.0 to 2.5%
Mn은 오스테나이트/페라이트 변태 개시 온도에 큰 영향을 주고 변태 개시 온도를 저하시키는 원소로서, 파이프 모재부 및 용접부의 인성에 영향을 미치며, 고용강화 원소로써 강도 증가에 기여한다. 그 함량이 1.0% 미만에서는 상기의 효과를 기대하기 어려운 반면 2.5%를 초과하는 경우에는 편석대가 발생할 가능성이 높다. 따라서, 상기 Mn의 함량은 1.0~2.5%로 제한하는 것이 바람직하다.
Mn is an element that greatly affects the austenite / ferrite transformation initiation temperature and lowers the transformation initiation temperature, affects the toughness of the pipe base material portion and the welded portion, and contributes to the strength increase as a solid solution strengthening element. If the content is less than 1.0%, it is difficult to expect the above effect, whereas if the content exceeds 2.5%, the segregation zone is likely to occur. Therefore, the content of Mn is preferably limited to 1.0 to 2.5%.
인(P): 0.02% 이하Phosphorus (P): not more than 0.02%
P은 고용강화 원소로서, 오스테나이트/페라이트 변태 개시 온도를 대폭적으로 상승시키는 작용을 하고, 조대한 페라이트 입자를 형성하는데 유용하게 작용한다. 그 함량이 0.02%를 초과하는 경우 상기의 효과를 확보하기 어려우므로, 상기 P의 함량은 0.02% 이하로 제한하는 것이 바람직하다. 보다 바람직하게는 0.015% 이하이다.
P is a solid solution strengthening element, which functions to significantly increase the austenite / ferrite transformation start temperature and is useful for forming coarse ferrite particles. When the content exceeds 0.02%, it is difficult to secure the above effect. Therefore, the P content is preferably limited to 0.02% or less. More preferably, it is 0.015% or less.
황(S): 0.01% 이하Sulfur (S): not more than 0.01%
S는 조대한 개재물을 형성하기 쉬운 원소이고, 인성 저하나 크랙 진전을 조장하므로 가능한 한 낮게 제한하는 것이 바람직하므로, 상기 S의 함량은 0.01% 이하로 제한하는 것이 바람직하다. 보다 바람직하게는 0.005% 이하이다.
S is an element which is easy to form coarse inclusions and promotes toughness and crack propagation, so it is preferable to limit the S content to as low as possible, and therefore, the content of S is preferably limited to 0.01% or less. More preferably, it is 0.005% or less.
칼슘(Ca): 0.001~0.006%Calcium (Ca): 0.001 to 0.006%
Ca상기 Ca는 유화물의 형태 제어를 위해 첨가한다. 그 함량이 0.006%를 초과하는 경우, 소강 중의 S량에 대하여 과다 첨가되어 CaO 클러스터(cluster)의 CaS가 발생하는 반면, 0.001% 미만인 경우에는 MnS가 발생하고, 인성의 저하를 초래할 수 있다. 또한, S량이 많다면 CaS 클러스터가 발생을 방지하기 위해 동시에 S량도 제어하는 것이 바람직하다. 즉, 철중의 S량 및 O량에 따라 Ca량을 제어하는 것이 바람직하다. 따라서, 상기 Ca의 함량은 0.001~0.006%로 하는 것이 바람직하다.
Ca The Ca is added to control the morphology of the emulsion. When the content exceeds 0.006%, CaS in the CaO cluster is generated in excess of the amount of S in the low-temperature steel, whereas when the content is less than 0.001%, MnS is generated and toughness may be lowered. If the amount of S is large, it is preferable to control the amount of S at the same time in order to prevent the occurrence of CaS clusters. That is, it is preferable to control the Ca amount according to the S amount and O amount of iron. Therefore, the content of Ca is preferably 0.001 to 0.006%.
알루미늄(Al): 0.01~0.06%Aluminum (Al): 0.01 to 0.06%
Al은 제강시의 탈산을 위해 첨가한다. 그 함량이 0.01% 미만인 경우 이러한 작용이 부족한 반면, 0.06%를 초과하는 경우 전기저항 용접시 용접부에 알루미나 또는 알루미나 산화물을 포함하는 복합 산화물의 형성이 조장되고 용접부 인성을 손상시킬 수 있다. 따라서 상기 Al의 함량은 0.01~0.06%로 하는 것이 바람직하다. 보다 바람직하게는 0.015~0.05%이다.
Al is added for deoxidation during steelmaking. If the content is less than 0.01%, such action is insufficient. If the content is more than 0.06%, the formation of a composite oxide containing alumina or alumina oxide may be promoted in the welded portion during the electric resistance welding, and the toughness of the welded portion may be damaged. Therefore, the content of Al is preferably 0.01 to 0.06%. More preferably, it is 0.015 to 0.05%.
질소(N): 0.008% 이하Nitrogen (N): Not more than 0.008%
N는 고용 상태에서는 시효 열화를 일으키는 원인이므로, Ti, Al등의 질화물로서 고정된다. 그 함량이 0.008%를 초과하는 경우 Ti, Al등의 첨가량 증가가 불가피하므로, 상기 N의 함량은 0.008%이하로 제한하는 것이 바람직하다. 보다 바람직하게는 0.005%이하이다.
N is fixed as a nitride such as Ti, Al or the like because it causes aging deterioration in the employment state. When the content exceeds 0.008%, the addition amount of Ti, Al or the like is inevitably increased. Therefore, the content of N is preferably limited to 0.008% or less. More preferably, it is 0.005% or less.
니오븀(Nb): 0.01~0.03%Niobium (Nb): 0.01 to 0.03%
Nb는 소량 첨가에 의해 석출강화 효과를 확보할 수 있는 성분으로, 0.03% 초과시 석출강화에 의해 충격특성이 저하되게 되므로, 그 함량을 0.03% 이하로 하는 것이 바람직하며, 0.01% 미만에서는 석출강화 효과를 얻을 수 없으므로, 그 함량은 0.01~0.03%로 하는 것이 바람직하다.
Nb is a component capable of ensuring the precipitation strengthening effect by the addition of a small amount of Nb. When the Nb content exceeds 0.03%, the impact characteristics are deteriorated by precipitation strengthening. Therefore, the content of Nb is preferably 0.03% , The content thereof is preferably 0.01 to 0.03%.
티타늄(Ti): 0.005~0.04%Titanium (Ti): 0.005 to 0.04%
Ti는 강중에서 TiN으로 석출되어 재가열시 오스테나이트의 결정립 성장을 억제함으로써, 고강도 및 고인성을 얻을 수 있게 하며, TiC 등으로 석출되어 강을 강화하는 역할을 한다. 이러한 역할을 위해서는 0.005% 이상이 필요하나, 그 함량이 0.04%를 초과하게 되면, 슬라브 결함을 유발할 수 있다.
Ti is precipitated as TiN in the steel to inhibit the growth of austenite grains during reheating, thereby obtaining high strength and high toughness, and precipitating with TiC and strengthening the steel. For such a role, 0.005% or more is required, but if the content exceeds 0.04%, slab failure may be caused.
보론(B): 0.001~0.003%Boron (B): 0.001 to 0.003%
B는 강의 경화능을 증가시켜 강재의 강도를 증가시키는데 유용하다. 이를 위해서는 0.001% 이상 포함되어야 하나, 그 함량이 0.003%를 초과하는 경우에는 경화능이 너무 증가하여 충격인성이 나빠지게 되므로, 상한은 0.003%로 하는 것이 바람직하다.
B is useful for increasing the hardenability of the steel to increase the strength of the steel. For this purpose, the content should be 0.001% or more. If the content is more than 0.003%, the hardenability is excessively increased and the impact toughness is deteriorated. Therefore, the upper limit is preferably 0.003%.
상기 조성 이외에 나머지는 Fe 및 불가피한 불순물을 포함한다. 다만, 본 발명의 기술사상을 벗어나지 않는 범위에서 다른 합금성분의 추가를 배재하지는 않는다.
In addition to the above composition, the balance includes Fe and unavoidable impurities. However, the addition of other alloying elements is not excluded from the scope of the present invention.
본 발명에서 상기 C 및 Mn의 함량은 {(C/12)+(Mn/55)}*100 ≤ 4.6의 관계(관계식 1)를 만족하는 것이 바람직하다. In the present invention, the content of C and Mn preferably satisfies the relationship (relational expression 1): {(C / 12) + (Mn / 55)} 100?
상기 관계식 1은 슬라브 내부에 편석을 억제하기 위한 것이다. C의 함량과 Mn의 함량 증가는 슬라브의 응고 온도를 낮추어 슬라브 중심의 편석을 조장하며, 델타 페라이트의 구간을 좁게하여 연주 중 슬라브의 균질화를 어렵게 한다. 또한, Mn은 슬라브 중심부에 편석되는 대표적인 원소로서 파이프의 연성을 해지는 제2상의 형성을 조장하며, C의 증가는 연주시 고상 및 액상의 공존 구간을 넓혀 편석을 심하시키게 된다. 따라서, 상기 관계식 1의 값이 4.6을 초과하게 되면, 강도는 증가하나, 상기의 이유로 슬라브의 비균질성이 증가하여 슬라브에 경한 제2상이 형성되게 된다. 따라서, 충격인성과 내HIC 특성을 확보하기 위해서는 관계식 1의 값이 4.6 이하인 것이 바람직하다.
The above relational expression 1 is for suppressing segregation in the inside of the slab. Increasing the content of C and Mn increases the segregation of the center of the slab by lowering the solidification temperature of the slab and narrowing the section of the delta ferrite, making it difficult to homogenize the slab during the performance. Further, Mn promotes the formation of the second phase, which is a typical element segregated in the central portion of the slab, which softens the pipe. The increase of C widens the coexistence section between the solid phase and the liquid phase during the performance, and segregation becomes severe. Therefore, if the value of the above relational expression 1 exceeds 4.6, the strength is increased, but the non-homogeneity of the slab is increased due to the above-mentioned reason, resulting in the formation of the light blue phase in the slab. Therefore, in order to ensure the impact toughness and the HIC resistance, the value of the relational expression 1 is preferably 4.6 or less.
이하, 본 발명의 미세조직에 대해 상세히 설명한다. 본 발명 열연강판은 면적분율로, 페라이트 기지조직에 5~15%의 펄라이트를 제2상으로 포함한다. 본 발명에서는 강관의 강도를 확보하기 위해서는 5% 이상의 펄라이트를 포함하는 것이 발람직하나, 15%를 초과하는 경우에는 인성이 저하될 우려가 있다.
Hereinafter, the microstructure of the present invention will be described in detail. The hot-rolled steel sheet of the present invention has an area fraction of 5 to 15% of pearlite in the ferrite matrix as the second phase. In the present invention, in order to secure the strength of the steel pipe, the inclusion of 5% or more of pearlite is preferable, and if it is more than 15%, the toughness may decrease.
한편, 본 발명은 강 내에 비금속 개재물을 포함한다. Al2O3, AlMgO, AlCaO, CaS 등이 있다.On the other hand, the present invention includes nonmetallic inclusions in the steel. Al 2 O 3 , AlMgO, AlCaO, CaS and the like.
상기 비금속 개재물은 크기가 20㎛ 이상인 것이 관찰면적 100*50㎟당 60개 이하인 것이 바람직하다. 본 발명에서는 균열발생 주위의 조직과 경도에 따라서 균열발생 기점이 되는 비금속 개재물의 크기가 다르다는 점을 기반하여 비금속 개재물 분율을 적절히 제어한다. 관찰면적 100*50㎟당 20㎛ 이상의 비금속 개재물이 60개 이하를 가지도록 하여 내수소유기균열성을 개선할 수 있다. 상기 60개를 초과하는 경우에는 수소유기균열의 개시점 역할을 하게 되어 내수소유기균열성의 저하를 초래할 수 있다.
The nonmetallic inclusions preferably have a size of 20 mu m or more and 60 or less per observation area of 100 * 50mm2. In the present invention, the nonmetallic inclusion fraction is appropriately controlled based on the fact that the sizes of the nonmetallic inclusions which are the origin of the cracks are different depending on the texture and the hardness around the cracks. The hydrogen-organic cracking resistance can be improved by making 60 or less non-metallic inclusions of 20 占 퐉 or more per 100 * 50 mm2 of observation area. If the number exceeds 60, it may act as a starting point of hydrogen organic cracking, which may result in deterioration of hydrogen-organic cracking resistance.
이하, 본 발명의 제조방법에 대해 상세히 설명한다. Hereinafter, the production method of the present invention will be described in detail.
본 발명 열연강판의 제조방법은 상기 조성 및 관계식을 만족하는 강 슬라브를 준비하는 단계; 재가열하는 단계; 상기 재가열된 강 슬라브를 열간압연하는 단계; 및 상기 열간압연 후 냉각하고 권취하는 단계를 포함한다.
A method of manufacturing a hot-rolled steel sheet according to the present invention includes the steps of preparing a steel slab satisfying the above composition and relational expression; Reheating; Hot-rolling the reheated steel slab; And cooling and winding after the hot rolling.
상기 강 슬라브는 정련 과정을 거친 용강을 주조하여 제조된다. 본 발명에 따른 비금속 개재물의 제어를 위해서는 2차 정련과정에서의 공정조건 제어를 통해 얻어질 수 있는데, 일예로, 2차 정련 공정은 전로(LF)에서 Ar 버블링을 하거나, VTD(Vacuum Tank Degasser) 또는 RH 등과 같은 탈가스 공정에서 Ar 버블링에 의해 개재물을 제어할 수 있다. 본 발명은 이러한 공정조건에 반드시 제한되는 것이 아니며, 어떠한 방법이어도 무방하다.
The steel slab is manufactured by casting molten steel subjected to a refining process. In order to control the nonmetallic inclusions according to the present invention, the secondary refining process may be performed by controlling the process conditions in the secondary refining process. For example, the secondary refining process may be performed by Ar bubbling in a converter (LF) or by using a Vacuum Tank Degasser ) Or RH or the like, the inclusions can be controlled by Ar bubbling. The present invention is not necessarily limited to these process conditions, and any method may be used.
상기 재가열은 1150~1300℃인 것이 바람직하다. 본 발명에서 재가열 온도는 Nb계 석출물의 고용온도에 의해 결정되며, 본 발명의 성분범위에서는 1150℃ 이상에서 고용이 가능하며, 1300℃를 초과하여 가열하는 경우는 강재의 결정립도가 매우 커져 인성이 저하되므로 1150~1300℃로 재가열 하는 것이 바람직하다.
The reheating is preferably 1150 to 1300 ° C. In the present invention, the reheating temperature is determined by the solid solution temperature of the Nb-based precipitate. In the component range of the present invention, the solid solution can be solidified at a temperature of 1150 DEG C or higher. When heated above 1300 DEG C, So it is preferable to reheat to 1150 to 1300 占 폚.
상기 열간압연시 마무리 압연은 Ar3 이상의 온도에서 행하는 것이 바람직하다. 70% 이상의 압하량으로 행하는 것이 바람직하다. Ar3 이상에서 압연을 마무리 하는 것은 Ar3 미만 온도에서는 페라이트 변태를 개시하며 이때 압연이 되면 수소유기균열저항성이 매우 낮아지므로, Ar3 이상에서 압연을 마무리하는 것이 바람직하다. 한편, 미재결정온도 미만에서 압하량은 열연강재 미세조직의 결정입도 및 균일성에 매우 큰 영향을 끼치며 결정입도 및 균일성은 수소유기균열 저항성 및 저온인성에 영향이 크다. 따라서, 압하량이 70% 미만인 경우에는 결정입도의 균질성이 저하되어 저온인성이 저하되므로 70% 이상의 압하량을 압연하는 것이 바람직하다.The finish rolling during the hot rolling is preferably performed at a temperature of Ar3 or higher. It is preferable to perform the reduction with a reduction of 70% or more. Finishing the rolling at Ar3 or above would initiate ferrite transformation at temperatures below Ar3, which would result in extremely low hydrogen organic cracking resistance when rolled, so it is desirable to finish rolling at Ar3 or above. On the other hand, when the temperature is lower than the non-recrystallization temperature, the reduction amount greatly affects the crystal grain size and uniformity of the hot-rolled steel microstructure, and the crystal grain size and uniformity are greatly influenced by hydrogen organic cracking resistance and low temperature toughness. Therefore, when the reduction amount is less than 70%, the homogeneity of the crystal grain size is lowered and the low temperature toughness is lowered. Therefore, it is desirable to roll a reduction amount of 70% or more.
상기 냉각은 Ar3 온도 이상에서 개시해야 하며, 그 미만의 온도에서 개시되는 경우, 냉각 전에 조대한 페라이트가 형성되어 인성을 저하시키는 원인이 된다. 따라서 Ar3 온도 이상에서 냉각을 개시하며 냉각속도가 느린 경우 수소유기균열 저항성을 떨어뜨리는 펄라이트 조직 형성이 용이하며, 빠른 경우는 베이나이트 형성이 용이하기 때문에 냉각속도는 10~30℃/sec의 냉각속도로 냉각하는 것이 바람직하다. 한편, 상기 권취는 450~680℃의 온도에서 행하는 것이 바람직하며, 680℃ 초과의 온도에서 권취를 하는 경우는 변태가 불안정하여 펄라이트 조직 형성이 가능하며, 450℃ 미만에서는 강재의 강성이 커 권취가 매우 어렵다.
The cooling should start at an Ar3 temperature or higher, and if it is started at a temperature lower than the Ar3 temperature, coarse ferrite is formed before cooling to lower the toughness. Therefore, it is easy to form the pearlite structure which lowers the organic cracking resistance when the cooling is started at a temperature above the Ar3 temperature and the cooling rate is slow. In the case of a rapid bainite formation, the cooling rate is 10 to 30 DEG C / . ≪ / RTI > On the other hand, the winding is preferably carried out at a temperature of 450 to 680 DEG C, and when the winding is performed at a temperature higher than 680 DEG C, the transformation is unstable and pearlite structure formation is possible. It is very difficult.
한편, 본 발명의 상기 열연강판을 이용하여, 조관된 파이프는 다음과 같은 특징을 갖는다. 조관 방법은 특별히 한정되지 않으나, 일예로는 전기저항용접을 이용하여 용접된 강관의 형태로 조관되는 것이 바람직하다. On the other hand, using the hot-rolled steel sheet of the present invention, a pipe that has been gouged has the following characteristics. The tube making method is not particularly limited, but for example, it is preferable that the tube is formed in the form of a welded steel tube using electric resistance welding.
상기 조관된 강관을 900~950℃에서 오스테나이징 한 후, 650~700℃에서 2~3분간 템퍼링 열처리를 행한다. 상기 오스테나이징 처리 및 템퍼링 열처리를 통해, 본 발명의 강관은 우수한 항복강도와 저온인성을 확보할 수 있으며, 내HIC 특성을 향상시킬 수 있다.
The tubular steel pipe is austenized at 900 to 950 占 폚 and then subjected to a tempering heat treatment at 650 to 700 占 폚 for 2 to 3 minutes. Through the austenizing treatment and the tempering heat treatment, the steel pipe of the present invention can secure an excellent yield strength and a low temperature toughness, and can improve the HIC characteristics.
본 발명의 강관은 항복강도가 580MPa 이상, 0℃에서의 충격에너지가 170J 이상이며, NACE TM0284에 따라서 0.1기압 H2S 가스로 포화된 pH5 인 용액 중에서 행하여지는 수소유기균열저항성 평가시험에서 HIC 크랙이 발생하지 않아, 우수한 내수소유기균열 저항성을 확보할 수 있다.
The steel pipe of the present invention has a HIC crack in the hydrogen organic cracking resistance evaluation test performed in a solution having a yield strength of 580 MPa or more, an impact energy at 0 DEG C of 170 J or more, and a pH of 5 saturated with 0.1 atm H 2 S gas according to NACE TM0284 And therefore excellent hydrogen-organic crack resistance can be ensured.
이하, 본 발명의 실시예에 대해 상세히 설명한다. 하기 실시예는 본 발명의 이해를 위한 것일 뿐, 본 발명을 한정하는 것은 아니다.Hereinafter, embodiments of the present invention will be described in detail. The following examples are for the purpose of understanding the present invention and are not intended to limit the present invention.
(실시예)(Example)
하기 표 1과 같이 조성(중량%, 나머지는 Fe 및 불가피한 불순물임)되는 강을 1200℃ 범위에서 2.5시간 동안 재가열한 후, 900℃ 이상에서 마무리 열간압연 및 냉각개시하고, 600℃ 범위에서 권취하여 강재를 제조하였다.The steel having the composition (% by weight, the balance being Fe and unavoidable impurities) was reheated in the range of 1200 ° C for 2.5 hours as shown in Table 1, and then subjected to finish hot rolling and cooling at 900 ° C or higher. A steel material was prepared.
이 강재를 이용하여 전기저항법을 이용하여 7인치로 강관을 조관하고, 고주파 열처리 실험 장비를 이용하여 하기 표 2의 방법으로 열처리를 실시하였다. 이후, 상기 강관의 항복강도, 내수소유기균열성, 충격인성 및 개재물을 관찰하여 그 결과를 표 2에 나타내었다.
Using this steel material, a steel pipe with a diameter of 7 inches was formed by using an electric resistance method, and heat treatment was carried out by the method of the following Table 2 using a high frequency heat treatment experimental equipment. Then, the yield strength, hydrogen-induced organic cracking resistance, impact toughness and inclusions of the steel pipe were observed, and the results are shown in Table 2.
상기 강관의 수소유기균열저항성은 NACE TM0284에 따라서 0.1기압 H2S 가스로 포화된 pH 5 용액 중에서 행하였고, 초음파 탐상법에 의해 균열 발생여부를 관찰하였다. 강관에 존재하는 개재물의 분포와 크기는 발광분광분석기 (Optical Emission Spectroscopy)를 이용하여 측정하였다. 발광분석기는 금속시편의 표면에 50㎛ 정도의 영역을 급속 가열하여 플라즈마를 생성하여 방출되는 원소의 특성 스펙트럼을 분석하여 비금속 개재물을 분석하게 된다. 통계적으로 의미있는 값을 얻기 위하여 동일한 시편에 대하여 여러 부분을 연속적으로 분석하여 개재물 분포를 측정하였다.
The hydrogen organic cracking resistance of the steel tube was measured in a pH 5 solution saturated with 0.1 atm H 2 S gas according to NACE TM0284, and the occurrence of cracking was observed by ultrasonic flaw detection. The distribution and size of the inclusions in the steel pipe were measured by using optical emission spectroscopy. In the luminescence analyzer, plasma is generated by rapidly heating a region of about 50 μm on the surface of a metal specimen, and a characteristic spectrum of an emitted element is analyzed to analyze nonmetallic inclusions. In order to obtain statistically significant values, the inclusion distribution was measured by continuously analyzing several parts of the same specimen.
식 1은 관계식 1을 의미하며, 이는 {(C/12)+(Mn/55)}*100 임.
Equation 1 means the relation 1, which is {(C / 12) + (Mn / 55)} * 100.
상기 개재물 수는 관찰면적 100*50㎟당 개수이다.
The number of inclusions is the number per 100 * 50 mm 2 of observation area.
상기 표 2에 나타난 바와 같이, 본 발명의 성분 범위를 만족하는 발명강 A와 B를 이용하여 본 발명의 제조 방법에 따라 제조된 발명재 1, 2 및 3의 경우 항복강도가 580MPa 이상이고, 0℃에서의 충격에너지 값이 170J 이상이며, HIC크랙이 발생하지 않았다.
As shown in Table 2, in the case of inventive materials 1, 2 and 3 produced according to the manufacturing method of the present invention using inventive steels A and B satisfying the composition range of the present invention, the yield strength was 580 MPa or more and 0 The impact energy value at 170 DEG C was 170 J or more, and no HIC crack occurred.
이에 비해 본 발명의 조성 및 공정을 만족하지 못하는 비교예 1 및 2는 내HIC 특성이 열위하거나, 저온인성이 열위한 것을 알 수 있다.
In contrast, Comparative Examples 1 and 2, which do not satisfy the composition and process of the present invention, show that the internal HIC characteristic is inferior or the low temperature toughness is heated.
Claims (10)
상기 C 및 Mn은 {(C/12)+(Mn/55)}*100 ≤ 4.6 을 만족하는 내HIC 특성이 우수한 고강도 고인성 열연강판.
0.1 to 0.5% of Si, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% or less of P (excluding 0), S of 0.01% or less (excluding 0), Ca of 0.001 0.001 to 0.006% of Al, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), 0.01 to 0.03% of Nb, 0.005 to 0.04% of Ti, 0.0001 to 0.003% of B and the balance of Fe and unavoidable impurities Including,
Wherein said C and Mn satisfy the following formula: {(C / 12) + (Mn / 55)} 100? 4.6.
상기 열연강판은 내부에 개재물을 포함하고, 상기 개재물은 크기가 20㎛ 이상인 것이 관찰면적 100*50㎟당 60개 이하인 내HIC 특성이 우수한 고강도 고인성 열연강판.
The method according to claim 1,
Wherein the hot-rolled steel sheet has an inclusion therein, and the inclusions have an HIC characteristic of 20 or less in size and 60 or less in an observation area of 100 * 50 mm 2.
상기 열연강판의 미세조직은 페라이트 기지조직에 면적분율로 5~15%의 펄라이트를 포함하는 내HIC 특성이 우수한 고강도 고인성 열연강판.
The method according to claim 1,
The microstructure of the hot-rolled steel sheet has excellent HIC characteristics including 5 to 15% pearlite in an area fraction in a ferrite matrix.
상기 강 슬라브를 재가열하는 단계;
재가열된 강 슬라브를 열간압연하고, Ar3 이상의 마무리 압연온도에서 열간압연하는 단계; 및
열간압연 후 냉각하고, 480~680℃의 온도에서 권취하는 단계
를 포함하는 내HIC 특성이 우수한 고강도 고인성 열연강판의 제조방법.
0.1 to 0.5% of Si, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% or less of P (excluding 0), S of 0.01% or less (excluding 0), Ca of 0.001 0.001 to 0.006% of Al, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), 0.01 to 0.03% of Nb, 0.005 to 0.04% of Ti, 0.0001 to 0.003% of B and the balance of Fe and unavoidable impurities (C / 12) + (Mn / 55)} 100 < = 4.6;
Reheating the steel slab;
Hot-rolling the reheated steel slab and hot rolling at a finishing rolling temperature of Ar3 or higher; And
Cooling after hot rolling and winding at a temperature of 480 to 680 캜
Wherein the hot-rolled steel sheet has excellent HIC characteristics.
상기 재가열은 1150~1300℃의 온도범위로 행하는 내HIC 특성이 우수한 고강도 고인성 열연강판의 제조방법.
The method of claim 4,
Wherein the reheating is performed in a temperature range of 1150 to 1300 占 폚.
상기 열간압연의 압하율은 70% 이상인 내HIC 특성이 우수한 고강도 고인성 열연강판의 제조방법.
The method of claim 4,
Wherein the reduction ratio of the hot rolling is 70% or more.
상기 냉각시 냉각속도는 10~30℃/s인 내HIC 특성이 우수한 고강도 고인성 열연강판의 제조방법.
The method of claim 4,
Wherein the cooling rate during cooling is 10 to 30 DEG C / s.
상기 C 및 Mn은 {(C/12)+(Mn/55)}*100 ≤ 4.6 을 만족하며,
항복강도가 580MPa 이상인 내HIC 특성이 우수한 고강도 고인성 강관.
0.1 to 0.5% of Si, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% or less of P (excluding 0), S of 0.01% or less (excluding 0), Ca of 0.001 0.001 to 0.006% of Al, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), 0.01 to 0.03% of Nb, 0.005 to 0.04% of Ti, 0.0001 to 0.003% of B and the balance of Fe and unavoidable impurities Including,
Wherein C and Mn satisfy the following formula: {(C / 12) + (Mn / 55)} 100? 4.6,
High strength high strength steel pipe with excellent HIC characteristics with a yield strength of 580 MPa or more.
상기 강관은 0℃에서의 충격에너지가 170J 이상인 내HIC 특성이 우수한 고강도 고인성 강관.
The method of claim 8,
The high-strength high-strength steel pipe excellent in the HIC characteristic having an impact energy of 170 J or more at 0 캜.
상기 강 슬라브를 재가열하는 단계;
재가열된 강 슬라브를 열간압연하고, Ar3 이상의 마무리 압연온도에서 열간압연하는 단계;
열간압연 후 냉각하고, 480~680℃의 온도에서 권취하여 열연강판을 제조하는 단계;
상기 열연강판을 조관하여 강관을 제조하는 단계;
상기 제조된 강관을 900~950℃에서 오스테나이징 처리하고, 650~700℃에서 2~3분간 템퍼링 열처리하는 단계
를 포함하는 내HIC 특성이 우수한 고강도 고인성 강관의 제조방법.
0.1 to 0.5% of Si, 0.2 to 0.5% of Si, 1.0 to 2.5% of Mn, 0.02% or less of P (excluding 0), S of 0.01% or less (excluding 0), Ca of 0.001 0.001 to 0.006% of Al, 0.01 to 0.06% of Al, 0.008% or less of N (excluding 0), 0.01 to 0.03% of Nb, 0.005 to 0.04% of Ti, 0.0001 to 0.003% of B and the balance of Fe and unavoidable impurities (C / 12) + (Mn / 55)} 100 < = 4.6;
Reheating the steel slab;
Hot-rolling the reheated steel slab and hot rolling at a finishing rolling temperature of Ar3 or higher;
Rolling after hot rolling and winding at a temperature of 480 to 680 캜 to produce a hot-rolled steel sheet;
Preparing a steel pipe for joining the hot-rolled steel sheet;
Austenizing the steel tube at 900 to 950 占 폚 and tempering the steel tube at 650 to 700 占 폚 for 2 to 3 minutes
And a high strength and high strength tough steel pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020130163207A KR101568520B1 (en) | 2013-12-24 | 2013-12-24 | High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020130163207A KR101568520B1 (en) | 2013-12-24 | 2013-12-24 | High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20150074944A true KR20150074944A (en) | 2015-07-02 |
| KR101568520B1 KR101568520B1 (en) | 2015-11-11 |
Family
ID=53787975
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020130163207A KR101568520B1 (en) | 2013-12-24 | 2013-12-24 | High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR101568520B1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101714913B1 (en) * | 2015-11-04 | 2017-03-10 | 주식회사 포스코 | Hot-rolled steel sheet having excellent resistance of hydrogen induced crack and sulfide stress crack for use in oil well and method for manufacturing the same |
| WO2017099433A1 (en) * | 2015-12-10 | 2017-06-15 | 주식회사 포스코 | Wire rod and steel wire having excellent hydrogen induced cracking resistance, and manufacturing method therefor |
| KR20180072493A (en) * | 2016-12-21 | 2018-06-29 | 주식회사 포스코 | Hot rolled steel sheet for use in oil well pipe, steel pipe using the same and method for manufacturing thereof |
| KR20190076787A (en) * | 2017-12-22 | 2019-07-02 | 주식회사 포스코 | Hot-rolled steel sheet for use in oil well and method for manufacturing the same |
| US11155906B2 (en) | 2016-11-11 | 2021-10-26 | Posco | Pressure vessel steel having excellent hydrogen induced cracking resistance, and manufacturing method therefor |
| CN114951573A (en) * | 2022-04-26 | 2022-08-30 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for 12.9-grade fastener and production method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4102206B2 (en) | 2003-01-24 | 2008-06-18 | 新日本製鐵株式会社 | High-strength steel pipe with excellent workability and its manufacturing method |
| JP5278188B2 (en) | 2009-06-19 | 2013-09-04 | 新日鐵住金株式会社 | Thick steel plate with excellent resistance to hydrogen-induced cracking and brittle crack propagation |
-
2013
- 2013-12-24 KR KR1020130163207A patent/KR101568520B1/en active IP Right Grant
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101714913B1 (en) * | 2015-11-04 | 2017-03-10 | 주식회사 포스코 | Hot-rolled steel sheet having excellent resistance of hydrogen induced crack and sulfide stress crack for use in oil well and method for manufacturing the same |
| WO2017099433A1 (en) * | 2015-12-10 | 2017-06-15 | 주식회사 포스코 | Wire rod and steel wire having excellent hydrogen induced cracking resistance, and manufacturing method therefor |
| CN108138294A (en) * | 2015-12-10 | 2018-06-08 | 株式会社Posco | The excellent wire rod of hydrogen-induced cracking resistance, steel wire and their manufacturing method |
| US11155906B2 (en) | 2016-11-11 | 2021-10-26 | Posco | Pressure vessel steel having excellent hydrogen induced cracking resistance, and manufacturing method therefor |
| KR20180072493A (en) * | 2016-12-21 | 2018-06-29 | 주식회사 포스코 | Hot rolled steel sheet for use in oil well pipe, steel pipe using the same and method for manufacturing thereof |
| CN108265222A (en) * | 2016-12-21 | 2018-07-10 | Posco公司 | Hot rolled steel plate for oil well pipe, steel pipe and its manufacturing method using the steel plate |
| KR20190076787A (en) * | 2017-12-22 | 2019-07-02 | 주식회사 포스코 | Hot-rolled steel sheet for use in oil well and method for manufacturing the same |
| CN114951573A (en) * | 2022-04-26 | 2022-08-30 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for 12.9-grade fastener and production method thereof |
| CN114951573B (en) * | 2022-04-26 | 2024-04-02 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for 12.9-grade fastener and production method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| KR101568520B1 (en) | 2015-11-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5277648B2 (en) | High strength steel sheet with excellent delayed fracture resistance and method for producing the same | |
| KR101568520B1 (en) | High strength and toughness hot rolled steel sheet having excellent hic resistance, steel pipe produced by the same and method for manufacturing thereof | |
| KR101778406B1 (en) | Thick Plate for Linepipes Having High Strength and Excellent Excessive Low Temperature Toughness And Method For Manufacturing The Same | |
| KR101304824B1 (en) | API Steel Plate for Line Pipe and Method for Manufacturing the API Steel Plate | |
| KR101657823B1 (en) | Steel having excellent low temperature toughness and hydrogen induced cracking resistance and manufacturing method thereof | |
| KR101889186B1 (en) | High-strength hot-rolled steel plate having excellent hydrogen induced cracking resistance and dwtt toughness at low temperature, and method for manufacturing the same | |
| KR101889189B1 (en) | Ts 450mpa grade heavy guage steel sheet having excellent resistance to hydrogen induced cracking and method of manufacturing the same | |
| KR101560941B1 (en) | Hot rolled steel sheet for pipe having excellent strength and expending property and method for manufacturing the same | |
| KR20160078844A (en) | Steel sheet having excellent resistance to hydrogen induced cracking, and method of manufacturing the same | |
| KR100345704B1 (en) | A method of manufacturing high strength hot rolled steel strip with low susceptibility of SSCC | |
| KR20150124811A (en) | Steel sheet for line pipe and method of manufacturing the same | |
| KR101647226B1 (en) | Steel plate having excellent fracture resistance and yield ratio, and method for manufacturing the same | |
| KR101461730B1 (en) | Hot-rolled steel sheet having excellent hydrogen induced crack resistance and low temperature impact toughness and method of manufacturing the same | |
| KR102305429B1 (en) | High-strength steel sheet having excellent fatigue resistance, method for manufacturing thereof, and welded steel pipe using thereof | |
| KR102043521B1 (en) | Hot-rolled steel sheet for use in oil well and method for manufacturing the same | |
| KR101412372B1 (en) | Hot-rolled steel sheet and method of manufacturing the hot-rolled steel sheet | |
| KR101226471B1 (en) | Hot rolled steel sheet with low yield ratio and method for manufacturing the same | |
| KR101412376B1 (en) | Method for hot rolling and steel sheet of line pipe manufactured using the same | |
| KR101572319B1 (en) | Method of manufacturing hot-rolled steel sheet and high strength steel pipe | |
| KR101647213B1 (en) | Hot rolled steels having high strength, elongation and toughness for use in oil well tube and method for producing the same and steel pipe prepared by the same method for producing the same | |
| KR101639901B1 (en) | Hot rolled steels having excellent impact toughness and workability for use in oil well tube and method for producing the same and steel pipe prepared by the same | |
| KR101490561B1 (en) | Hot-rolled steel sheet having excellent hydrogen induced crack resistance and yield ratio and method of manufacturing the same | |
| KR101377890B1 (en) | High strength hot-rolled steel sheet and method of manufacturing the same | |
| JPH1112642A (en) | Manufacture of steel product for line pipe, excellent in sulfide corrosion cracking resistance | |
| KR20220087189A (en) | Steel sheet for pipe having excellent hydrogen induced crack resistance and method of manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| E701 | Decision to grant or registration of patent right | ||
| GRNT | Written decision to grant | ||
| FPAY | Annual fee payment |
Payment date: 20181102 Year of fee payment: 4 |