KR101553607B1 - Ferritic stainless steel having excellent ductility and method for manufacturing the same - Google Patents
Ferritic stainless steel having excellent ductility and method for manufacturing the same Download PDFInfo
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- KR101553607B1 KR101553607B1 KR1020150061378A KR20150061378A KR101553607B1 KR 101553607 B1 KR101553607 B1 KR 101553607B1 KR 1020150061378 A KR1020150061378 A KR 1020150061378A KR 20150061378 A KR20150061378 A KR 20150061378A KR 101553607 B1 KR101553607 B1 KR 101553607B1
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- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 title abstract description 14
- 239000002244 precipitate Substances 0.000 claims abstract description 52
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 36
- 239000010959 steel Substances 0.000 claims description 36
- 239000000463 material Substances 0.000 claims description 26
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 21
- 238000001816 cooling Methods 0.000 claims description 18
- 230000001419 dependent effect Effects 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 15
- 238000000137 annealing Methods 0.000 claims description 13
- 238000005266 casting Methods 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000005098 hot rolling Methods 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 3
- 238000003303 reheating Methods 0.000 claims 1
- 239000011159 matrix material Substances 0.000 abstract description 3
- 239000010936 titanium Substances 0.000 description 58
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 230000007797 corrosion Effects 0.000 description 7
- 238000005260 corrosion Methods 0.000 description 7
- 229910052719 titanium Inorganic materials 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 238000010899 nucleation Methods 0.000 description 4
- 230000006911 nucleation Effects 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000010583 slow cooling Methods 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- 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
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
- B22D11/002—Stainless steels
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- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
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- 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
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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Abstract
Description
본 발명은 연성이 우수한 페라이트계 스테인리스 강재 및 그 제조방법에 관한 것으로, 보다 상세하게는 오스테나이트계 스테인리스 강재에 비하여 연성이 나빠 고연성을 요하는 용도에 사용되기 어려웠던 페라이트계 스테인리스 강재의 연성을 향상시킨 신규한 페라이트계 스테인리스 강재 및 그 제조방법에 관한 것이다.
The present invention relates to a ferritic stainless steel material excellent in ductility and a method for producing the ferritic stainless steel material. More particularly, the present invention relates to a ferritic stainless steel material which is less ductile than an austenitic stainless steel material and hardly used in applications requiring ductility And a method of manufacturing the ferritic stainless steel material.
페라이트계 스테인리스 강재는 고가의 합금원소가 적게 첨가되면서도 내식성을 뛰어나서, 오스테나이트계 스테인리스 강재에 비하여 가격 경쟁력이 높은 강재이다. 페라이트계 스테인리스계 강재는 건축재료, 수송기기, 주방기기 등의 용도에 사용되고 있으나, 연성이 열위하여 많은 분야에서 오스테나이트계 스테인리스 강재를 대체하지 못하고 있다. 이에, 연성을 향상시켜 그 용도 확대를 도모하는 검토가 적극적으로 진행되고 있다.
Ferritic stainless steels are superior in corrosion resistance and have high price competitiveness compared to austenitic stainless steels, while adding a small amount of expensive alloying elements. Ferritic stainless steel steels are used in construction materials, transportation equipment, kitchen appliances, etc., but they are not replacing austenitic stainless steels in many fields in order to develop ductility. Accordingly, studies have been actively made to improve the ductility and expand the use thereof.
이를 해결하기 위해, 석출물의 총량 또는 개수를 제한함으로써 페라이트계 스테인리스 강재의 연성을 향상시키려는 시도가 이어져 왔으나, 현재까지 의미 있는 연구 성과는 전무한 실정이다.
In order to solve this problem, attempts have been made to improve the ductility of ferritic stainless steel by limiting the total amount or the number of precipitates, but there has been no meaningful research result to date.
본 발명의 일 측면은, 연성이 우수한 페라이트계 스테인리스 강재와 이를 제조하는 방법을 제공하고자 하는 것이다.
An aspect of the present invention is to provide a ferritic stainless steel material excellent in ductility and a method of manufacturing the ferritic stainless steel material.
본 발명의 과제는 상술한 내용에 한정하지 않는다. 본 발명의 추가적인 과제는 명세서 전반적인 내용에 기재되어 있으며, 본 발명이 속하는 기술분야의 통상적인 지식을 가지는 자라면 본 발명의 명세서로부터 본 발명의 추가적인 과제를 이해하는데 아무런 어려움이 없을 것이다.
The object of the present invention is not limited to the above description. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
본 발명의 일 측면의 일 실시형태는, 중량%로, C: 0.005~0.1%, Si: 0.01~2.0%, Mn: 0.01~1.5%, P: 0.05% 이하, S: 0.005% 이하, Cr: 10~30%, Ti: 0.005~0.5%, Al: 0.01~0.15%, N: 0.005~0.03%, 잔부 Fe 및 불가피한 불순물을 포함하고, 페라이트 기지에, 3.5×106개/mm2 이하의 Ti(CN) 독립 석출물을 포함하는 페라이트계 스테인리스 강재를 제공한다.
An embodiment of one aspect of the present invention is a steel sheet comprising, by weight percent, 0.005 to 0.1% of C, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% , Ti: 0.005-0.5%, Al: 0.01-0.15%, N: 0.005-0.03%, the balance being Fe and unavoidable impurities, and a ferrite base containing 3.5 x 10 6 / mm 2 or less Ti (CN) independent precipitates.
본 발명의 일 측면의 다른 일 실시형태는, 중량%로, C: 0.005~0.1%, Si: 0.01~2.0%, Mn: 0.01~1.5%, P: 0.05% 이하, S: 0.005% 이하, Cr: 10~30%, Ti: 0.005~0.5%, Al: 0.01~0.15%, N: 0.005~0.03%, 잔부 Fe 및 불가피한 불순물을 포함하고, 페라이트 기지에, Ti(CN) 독립 석출물과 TiN 개재물을 핵으로 하여 석출된 Ti(CN) 종속 석출물을 포함하고, 하기 식 1로 정의되는 PS가 60% 이하(0% 제외)인 페라이트계 스테인리스 강재를 제공한다.Another embodiment according to one aspect of the present invention is a ferritic stainless steel comprising 0.005 to 0.1% of C, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% or less of P, (CN) -dependent precipitates and TiN inclusions are added to the ferrite matrix in an amount of 10 to 30%, Ti to 0.005 to 0.5%, Al to 0.01 to 0.15%, N: 0.005 to 0.03%, and the balance Fe and unavoidable impurities And a Ti (CN) -dependent precipitate precipitated as a nucleus, wherein the P S defined by the following
[식 1][Formula 1]
PS(%)={NS/(NS+NC)} × 100P S (%) = {N S / (N S + N C )} × 100
(여기서, NS는 Ti(CN) 독립 석출물의 단위 면적 당 개수(개/mm2)이며, NC는 Ti(CN) 종속 석출물의 단위 면적 당 개수(개/mm2)를 의미함)
(Where N S is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 ) and N C is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 )
이때, 상기 Ti(CN) 독립 석출물의 입경은 0.01μm 이상일 수 있다.
At this time, the grain size of the Ti (CN) independent precipitate may be 0.01 탆 or more.
이때, 상기 Ti(CN) 독립 석출물의 평균 입경은 0.15μm 이하인 것이 바람직하다.
At this time, it is preferable that the average particle size of the Ti (CN) independent precipitate is 0.15 탆 or less.
이때, 상기 TiN 개재물의 평균 입경은 2μm 이상인 것이 바람직하다.
At this time, the average particle diameter of the TiN inclusions is preferably 2 탆 or more.
이때, 상기 스테인리스 강재의 연신율은 34% 이상일 수 있다.
At this time, the elongation of the stainless steel material may be 34% or more.
본 발명의 다른 일 측면은, 중량%로, C: 0.005~0.1%, Si: 0.01~2.0%, Mn: 0.01~1.5%, P: 0.05% 이하, S: 0.005% 이하, Cr: 10~30%, Ti: 0.005~0.5%, Al: 0.01~0.15%, N: 0.005~0.03%, 잔부 Fe 및 불가피한 불순물을 포함하는 용강을 슬라브로 주조하는 단계를 포함하는 페라이트계 스테인리스 강재의 제조방법에 있어서, 상기 용강의 주조시, 상기 슬라브의 표면 온도를 기준으로 1100~1200℃의 온도에서의 평균 냉각속도를 5℃/sec 이하(0℃/sec 제외)로 제어하는 것을 특징으로 하는 페라이트계 스테인리스 강재의 제조방법을 제공한다.
Another aspect of the present invention is to provide a ferritic stainless steel comprising 0.005 to 0.1% of C, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% or less of P, 0.005% or less of S, Casting a molten steel containing at least one of Fe, Ti, Ti and Al in an amount of 0.005 to 0.5%, 0.01 to 0.15% of Al, 0.005 to 0.03% of N, and the balance Fe and unavoidable impurities in a slab of a ferritic stainless steel material , And an average cooling rate at a temperature of 1100 to 1200 ° C is controlled to be 5 ° C / sec or less (excluding 0 ° C / sec) based on the surface temperature of the slab at the time of casting the molten steel. Of the present invention.
이때, 상기 용강의 주조시, 상기 슬라브의 표면 온도를 기준으로 1000~1250℃의 온도에서의 평균 냉각속도를 5℃/sec 이하(0℃/sec 제외)로 제어하는 것이 보다 바람직하다.
At this time, it is more preferable to control the average cooling rate at a temperature of 1000 to 1250 ° C to 5 ° C / sec or less (excluding 0 ° C / sec) based on the surface temperature of the slab when casting the molten steel.
이때, 상기 용강을 슬라브로 주조 후, 상기 슬라브를 열간압연하여 열연판을 얻는 단계; 및 상기 열연판을 450~1080℃의 온도에서 1~60분 동안 열연판 소둔하는 단계를 더 포함할 수 있다.
At this time, after casting the molten steel into a slab, hot rolling the slab to obtain a hot rolled steel sheet; And annealing the hot-rolled sheet at a temperature of 450 to 1080 ° C for 1 to 60 minutes.
본 발명에 따른 페라이트계 스테인리스 강재는 연성이 매우 우수한 장점이 있다.
The ferritic stainless steel material according to the present invention has an advantage of extremely excellent ductility.
도 1은 발명예 1에 따른 열연판의 미세조직을 관찰한 전자현미경(Scanning Electron Microscope, SEM) 사진이다.
도 2는 도 1의 A 부분을 확대하여 관찰한 전자현미경(Scanning Electron Microscope, SEM) 사진이다.1 is a scanning electron microscope (SEM) photograph showing a microstructure of a hot rolled sheet according to Inventive Example 1 observed.
FIG. 2 is a scanning electron microscope (SEM) photograph of a portion A of FIG. 1 taken on an enlarged scale.
본 발명자들은 페라이트계 스테인리스 강재의 연성을 향상시키기 위하여 다양한 검토를 행한 결과, 이하의 지견을 얻을 수 있었다.
The inventors of the present invention conducted various studies in order to improve the ductility of the ferritic stainless steel material, and the following findings were obtained.
(1) 일반적으로 페라이트계 스테인리스 강재에는 내식성 향상을 위해 미량의 Ti이 첨가되는데, 이러한 Ti 첨가 페라이트계 스테인리스 강재의 경우, 불가피하게 페라이트 기지 내 Ti(CN)이 다량 석출되며, 이러한 Ti(CN) 석출물은 강재의 연성을 열화시키는 주요 원인이 된다.
(1) Generally, a small amount of Ti is added to a ferritic stainless steel material in order to improve corrosion resistance. In the case of such a Ti-added ferritic stainless steel material, a large amount of Ti (CN) The precipitate is a main cause of deterioration of the ductility of the steel.
(2) 한편, Ti(CN) 석출물은, 페라이트 기지 내 독립적으로 석출되는 Ti(CN) 석출물(이하, 'Ti(CN) 독립 석출물'이라 함)과 제강에서 정출되는 TiN 개재물을 핵으로 하여 석출되는 Ti(CN) 석출물(이하, 'Ti(CN) 종속 석출물'이라 함)으로 이루어지는데, 이 중 Ti(CN) 종속 석출물은, Ti(CN) 독립 석출물과 비교할 때, 연성 열화에 크게 영향을 미치지 아니한다.
(2) On the other hand, the Ti (CN) precipitate is a precipitate of Ti (CN) precipitates independently precipitated in a ferrite matrix (hereinafter referred to as Ti Ti (CN) -dependent precipitates (hereinafter referred to as "Ti (CN) -dependent precipitates"). The Ti (CN) It does not go crazy.
(3) 따라서, Ti 첨가 페라이트계 스테인리스 강재의 연성을 향상시키기 위한 한가지 수단으로, 가능한 한 많은 Ti(CN)이 TiN 개재물을 핵으로 하여 종속 석출물로 석출되도록 유도하여, Ti(CN) 독립 석출물의 개수를 저감함으로써, 이를 달성할 수 있다.
(3) Therefore, as one means for improving the ductility of the Ti-added ferritic stainless steel material, it is possible to induce the Ti (CN) as much as possible to precipitate into the sintered precipitate with the TiN inclusion as nuclei, This can be achieved by reducing the number.
이하, 본 발명의 일 측면인 연성이 우수한 페라이트계 스테인리스 강재에 대하여 상세히 설명한다.
Hereinafter, a ferritic stainless steel material having excellent ductility, which is one aspect of the present invention, will be described in detail.
먼저 본 발명의 페라이트계 스테인리스 강재의 바람직한 조성에 대하여 상세히 설명한다. 후술하는 각 성분의 함량은 특별히 언급하지 않는 한 모두 중량 기준임을 미리 밝혀둔다.
First, the preferred composition of the ferritic stainless steel of the present invention will be described in detail. It is to be noted that the content of each component described below is based on weight unless otherwise specified.
C: 0.005~0.1% C: 0.005 to 0.1%
C는 강재의 강도에 크게 영향을 미치는 원소로써, 그 함량이 과다할 경우, 강재의 강도가 지나치게 상승하여 연성이 저하되는 바, 0.1% 이하로 한정한다. 다만, 그 함량이 지나치게 낮을 경우, 강도가 지나치게 저하되는 바, 그 하한을 0.005%로 한정할 수 있다.
C is an element that greatly affects the strength of the steel. When the content is excessive, the strength of the steel is excessively increased to deteriorate the ductility, which is limited to 0.1% or less. However, if the content is too low, the strength is excessively lowered, so that the lower limit can be limited to 0.005%.
Si: 0.01~2.0% Si: 0.01 to 2.0%
Si은 제강시 용강의 탈산과 페라이트 안정화를 위해 첨가되는 원소로, 본 발명에서는 0.01% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 재질의 경화를 일으켜 강의 연성이 저하되는 바, 2.0% 이하로 한정한다.
Si is an element added for deoxidation of molten steel during steelmaking and stabilization of ferrite. In the present invention, 0.01% or more Si is added. However, when the content is excessive, the material is hardened and ductility of the steel is lowered, and the content is limited to 2.0% or less.
Mn: 0.01~1.5% Mn: 0.01 to 1.5%
Mn은 내식성 개선에 유효한 원소로, 본 발명에서는 0.01% 이상 첨가하고, 보다 바람직하게는 0.5% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 용접시 Mn계 퓸 발생이 급증하여 용접성이 저하되며, 과도한 MnS 석출물 형성으로 인해 강의 연성이 저하되는 바, 1.5% 이하로 한정하며, 보다 바람직하게는 1.0% 이하로 한정한다.
Mn is an element effective for improving the corrosion resistance. In the present invention, 0.01% or more is added, and more preferably 0.5% or more is added. However, when the content is excessive, the occurrence of Mn-based fumes is rapidly increased at the time of welding, and the weldability is deteriorated, and the ductility of the steel is deteriorated due to the formation of excessive MnS precipitates. The content is limited to 1.5% or less, more preferably 1.0% .
P: 0.05% 이하 P: not more than 0.05%
인은 강 중 불가피하게 함유되는 불순물로써, 산세시 입계 부식을 일으키거나 열간 가공성을 저해하는 주요 원인이 되는 원소이므로, 그 함량을 가능한 한 낮게 제어하는 것이 바람직하다. 본 발명에서는 상기 인의 함량의 상한을 0.05%로 관리한다.
Phosphorus is an impurity that is inevitably contained in steel. It is an element that causes intergranular corrosion at the time of pickling or hinders hot workability. Therefore, it is desirable to control the content as low as possible. In the present invention, the upper limit of the phosphorus content is controlled to 0.05%.
S: 0.005% 이하 S: not more than 0.005%
황은 강 중 불가피하게 함유되는 불순물로써, 결정립계에 편석되어 열간 가공성을 저해하는 주요 원인이 되는 원소이므로, 그 함량을 가능한 한 낮게 제어하는 것이 바람직하다. 본 발명에서는 상기 황의 함량의 상한을 0.005%로 관리한다.
Since sulfur is an impurity inevitably contained in the steel, it is an element that is segregated in grain boundaries and is a main cause of inhibiting hot workability, and therefore, it is desirable to control the content as low as possible. In the present invention, the upper limit of the sulfur content is controlled to 0.005%.
Cr: 10~30%Cr: 10 to 30%
크롬은 강의 내식성 향상에 효과적인 원소로, 본 발명에서는 10% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 제조 비용이 급증할 뿐만 아니라, 입계 부식이 일어나는 문제가 있는 바, 30% 이하로 한정한다
Chromium is an element effective for improving the corrosion resistance of steel. In the present invention, it is added by 10% or more. However, if the content is excessive, not only does the production cost increase, but also intergranular corrosion occurs, so that the content is limited to 30% or less
Ti: 0.005~0.5%Ti: 0.005-0.5%
티타늄은 탄소 및 질소를 고정하여 강 중 고용 탄소 및 고용 질소의 양을 저감하고, 강의 내식성 향상에 효과적인 원소로, 본 발명에서는 0.005% 이상 첨가하고, 보다 바람직하게는 0.1% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 제조 비용이 급증할 뿐만 아니라, Ti계 개재물 형성으로 인해 표면 결함이 야기되는 바, 0.5% 이하로 한정하고, 보다 바람직하게는 0.3% 이하로 한정한다.
Titanium is an element effective in reducing the amount of solid carbon and nitrogen employed in steel by fixing carbon and nitrogen and improving the corrosion resistance of steel. In the present invention, 0.005% or more, and more preferably 0.1% or more is added. However, if the content is excessive, not only the production cost increases but also surface defects are caused by the formation of Ti inclusions. The content is limited to 0.5% or less, more preferably 0.3% or less.
Al: 0.01~0.15%Al: 0.01 to 0.15%
알루미늄은 강력한 탈산제로써, 용강 중 산소의 함량을 낮추는 역할을 하며, 본 발명에서는 0.01% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 비금속 개재물 증가로 인해 냉연 스트립의 슬리브 결함이 발생함과 동시에, 용접성을 열화시키는 바, 0.15% 이하로 한정하고, 보다 바람직하게는 0.1% 이하로 한정한다.
Aluminum is a powerful deoxidizing agent, which serves to lower the content of oxygen in molten steel. In the present invention, 0.01% or more of aluminum is added. However, when the content is excessive, the sleeve defect of the cold-rolled strip occurs due to the increase of the nonmetallic inclusions, and the weldability deteriorates, and is limited to 0.15% or less, more preferably 0.1% or less.
N: 0.005~0.03%N: 0.005 to 0.03%
질소는 열간 압연시 오스테나이트를 석출시켜 재결정을 촉진시키는 역할을 하는 원소로, 본 발명에서는 0.005% 이상 첨가한다. 다만, 그 함량이 과다할 경우, 강의 연성을 저하하는 바, 0.03% 이하로 한정한다.
Nitrogen is an element that accelerates recrystallization by precipitation of austenite during hot rolling. In the present invention, 0.005% or more of nitrogen is added. However, when the content is excessive, the ductility of the steel is deteriorated, and it is limited to 0.03% or less.
본 발명의 스테인리스 강재는, 페라이트 기지에 3.5×106개/mm2 이하(0개/mm2 제외)의 Ti(CN) 독립 석출물을 포함한다. 전술한 바와 같이, Ti(CN) 석출물은, Ti(CN) 독립 석출물과 TiN 개재물을 핵으로 하여 석출된 Ti(CN) 종속 석출물으로 이루어지는데, 이 중 Ti(CN) 종속 석출물은, Ti(CN) 독립 석출물과 비교할 때, 연성 열화에 크게 영향을 미치지 아니하는 바, 본 발명에서는 특별히 Ti(CN) 독립 석출물의 개수만을 제어한다. Ti(CN) 독립 석출물의 개수를 상기의 범위를 벗어날 경우, 목적하는 연성을 확보하기 어려운 문제가 있다.
The stainless steel material of the present invention contains a Ti (CN) independent precipitate of 3.5 × 10 6 / mm 2 or less (excluding 0 / mm 2 ) in a ferrite base. As described above, the Ti (CN) precipitate is composed of Ti (CN) -dependent precipitates and Ti (CN) -dependent precipitates precipitated with the TiN inclusion as nuclei. ) Independent precipitates do not greatly affect the deterioration of ductility, and the present invention specifically controls only the number of Ti (CN) independent precipitates. When the number of Ti (CN) independent precipitates is out of the above range, there is a problem that it is difficult to secure the desired ductility.
상기와 같이 Ti(CN) 독립 석출물의 개수를 저감하기 위한 한가지 수단으로, 가능한 한 많은 Ti(CN)이 TiN 개재물을 핵으로 석출되도록 유도함으로써 이를 달성할 수 있으며, 본 발명의 일 구현예에 따르면, 하기 식 1로 정의되는 PS를 60% 이하로 제어함으로써 목적하는 연성을 확보할 수 있다.As one way to reduce the number of Ti (CN) independent precipitates as described above, this can be achieved by inducing the TiN inclusions to precipitate into nuclei as much as possible, and according to one embodiment of the present invention , And the desired ductility can be ensured by controlling the P S defined by the following
[식 1][Formula 1]
PS(%)={NS/(NS+NC)} × 100P S (%) = {N S / (N S + N C )} × 100
(여기서, NS는 Ti(CN) 독립 석출물의 단위 면적 당 개수(개/mm2)이며, NC는 Ti(CN) 종속 석출물의 단위 면적 당 개수(개/mm2)를 의미함)
(Where N S is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 ) and N C is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 )
한편, 본 발명에서 개수 제어의 대상인 Ti(CN) 독립 석출물은, 입경이 0.01μm 이상의 Ti(CN) 독립 석출물로 한정될 수 있다. 입경 0.01μm 미만의 Ti(CN) 독립 석출물은 분석하여 정량화하는데 한계가 있는 바, 이에 대해서는 특별히 고려하지 않아도 무방하다. 한편, Ti(CN) 독립 석출물의 입경의 상한에 대해서는 특별히 한정하지 않으나, 통상적으로 2μm를 초과하는 입경을 가지는 Ti(CN) 독립 석출물은 형성되기 곤란한 바, 그 상한을 2μm으로 한정할 수는 있다.
On the other hand, in the present invention, the Ti (CN) independent precipitate to be subjected to the number control can be limited to Ti (CN) independent precipitates having a particle diameter of 0.01 탆 or more. There is a limitation in analyzing and quantifying Ti (CN) independent precipitates having a particle diameter of less than 0.01 탆, and this need not be considered particularly. On the other hand, although the upper limit of the particle diameter of the Ti (CN) independent precipitate is not particularly limited, it is difficult to form a Ti (CN) independent precipitate usually having a particle diameter exceeding 2 탆, and the upper limit can be limited to 2 탆 .
이때, 상기 Ti(CN) 독립 석출물의 평균 입경은 0.15μm 이하인 것이 바람직하다. 이는 Ti(CN) 독립 석출물의 평균 입경이 0.15μm를 초과할 경우, Ti(CN) 독립 석출물의 개수 저감에는 유리하나, 표면 흠 문제를 일으킬 우려가 있기 때문이다. 여기서, 평균 입경이란, 강재의 일 단면을 관찰하여 검출한 입자의 평균 원 상당 직경(equivalent circular diameter)을 의미한다.
At this time, it is preferable that the average particle size of the Ti (CN) independent precipitate is 0.15 탆 or less. This is because, when the average particle diameter of the Ti (CN) independent precipitate exceeds 0.15 m, it is advantageous to reduce the number of Ti (CN) independent precipitates, but there is a risk of causing a surface flaw. Here, the average particle diameter means an equivalent circular diameter of particles detected by observing one end face of the steel material.
이때, 상기 TiN 개재물의 평균 입경은 2μm 이상인 것이 바람직하다. 이는 평균 입경 2μm 이상의 상대적으로 조대한 TiN 개재물이, Ti(CN)의 석출을 위한 핵 생성 사이트로 작용하기에 유리하기 때문이다. 한편, TiN 개재물의 평균 입경의 상한에 대해서는 특별히 한정하지 않으나, TiN 개재물의 크기가 지나치게 조대할 경우, TiN 개재물의 전체 표면적이 지나치게 감소하여 Ti(CN) 종속 석출물 개수 증대에 불리한 영향을 미칠 수 있는 바, 그 상한을 20μm으로 한정할 수는 있다.
At this time, the average particle diameter of the TiN inclusions is preferably 2 탆 or more. This is because relatively coarse TiN inclusions having an average particle diameter of 2 占 퐉 or more are advantageous to serve as a nucleation site for precipitation of Ti (CN). On the other hand, the upper limit of the average particle size of the TiN inclusions is not particularly limited, but if the size of the TiN inclusions is excessively large, the total surface area of the TiN inclusions may be excessively decreased to adversely affect the increase in the number of Ti (CN) The upper limit of the bar can be limited to 20 μm.
본 발명의 페라이트계 스테인리스 강재는 연성이 매우 우수한 장점을 가진다. 본 발명의 일 구현예에 따르면, 본 발명의 페라이트계 스테인리스 강재의 연신율은 34% 이상일 수 있다.
The ferritic stainless steel material of the present invention has an advantage of extremely excellent ductility. According to one embodiment of the present invention, the elongation of the ferritic stainless steel of the present invention may be at least 34%.
이상에서 설명한 본 발명의 페라이트계 스테인리스 강재는 다양한 방법으로 제조될 수 있으며, 그 제조방법은 특별히 제한되지 않는다. 다만, 그 일 구현예로써 다음과 같은 방법에 의하여 제조될 수 있다.
The ferritic stainless steel material of the present invention described above can be produced by various methods, and the production method thereof is not particularly limited. However, it can be produced by the following method as one embodiment thereof.
이하, 본 발명의 다른 일 측면인 연성이 우수한 페라이트계 스테인리스 강재의 제조방법의 제조방법에 대하여 상세히 설명한다.
Hereinafter, a method of manufacturing a ferritic stainless steel material having excellent ductility, which is another aspect of the present invention, will be described in detail.
본 발명의 일 측면인 페라이트계 스테인리스 강재의 제조방법은, 전술한 조성을 가지는 용강을 슬라브로 주조하는 단계를 포함하는 페라이트계 스테인리스 강재의 제조방법에 관한 것으로, 본 발명에서는 Ti(CN)이 독립적으로 석출되는 것을 최대한 억제하기 위하여, Ti, C 및 N의 확산에 의해 TiN 개재물을 핵으로 하여 Ti(CN) 종속 석출물이 형성되도록 유도하는 것을 하나의 기술적 특징으로 한다.
A method for producing a ferritic stainless steel material according to one aspect of the present invention is a method for producing a ferritic stainless steel material including casting molten steel having the above composition into a slab. In the present invention, Ti (CN) In order to suppress the precipitation as much as possible, it is a technical feature that Ti (CN) -containing precipitates are formed using TiN inclusion as nuclei by diffusion of Ti, C and N.
일반적으로 용강의 주조시, 생산성 향상을 위해, 주조에 의해 얻어진 슬라브의 냉각을 실시한다. 그런데, 본 발명자들의 검토 결과, 통상적인 슬라브 냉각 속도에서는 상대적으로 미세한 TiN 개재물이 형성되고, Ti(CN)의 무작위 석출이 야기되며, 이는 Ti(CN) 독립 석출물의 개수를 크게 증가시키는 한가지 원인이 된다. 이는, 냉각이 비교적 빠르게 진행되어 합금 원소들의 확산이 제한되고, 핵생성 에너지가 충분히 제공되어 여러 장소에서 동시다발적으로 TiN 개재물 및 Ti(CN) 석출물의 핵생성이 조장되기 때문으로 추측된다.
Generally, during casting of molten steel, the slab obtained by casting is cooled to improve the productivity. As a result of examinations by the present inventors, it has been found that at a typical slab cooling rate, relatively fine TiN inclusions are formed and random precipitation of Ti (CN) is caused, which is one cause of a large increase in the number of Ti (CN) do. This is presumably because cooling progresses relatively fast, diffusion of alloying elements is limited, and sufficient nucleation energy is provided, which promotes the nucleation of TiN inclusions and Ti (CN) precipitates simultaneously and in many places.
이에 반해, 본 발명에서는 상기 용강의 주조시, 상기 슬라브의 표면 온도를 기준으로 1100~1200℃의 온도에서의 평균 냉각속도를 5℃/sec 이하(0℃/sec 제외)로, 보다 바람직하게는 3℃/sec 이하(0℃/sec 제외)로, 보다 더 바람직하게는 2℃/sec 이하(0℃/sec 제외)로 제어한다. 즉, 본 발명자들은 1100~1200℃의 온도에서의 슬라브의 평균 냉각 속도를 적절히 제어함으로써, 가능한 한 많은 Ti(CN) 이 TiN 개재물을 핵으로 석출되도록 유도함으로써, Ti(CN) 독립 석출물의 개수를 저감하고자 하였으며, 상기의 조건 하 슬라브의 냉각을 실시함으로써 Ti(CN) 독립 석출물의 개수를 목표 개수 이하로 저감할 수 있음을 알아내었다. 이는 서냉에 따라 합금 원소들의 이동에 필요한 시간이 충분히 확보되었기 때문에, 다량의 Ti, C 및 N이 에너지가 높은 TiN 개재물 주위로 확산되어 이를 핵으로 Ti(CN)이 석출되었기 때문으로 추측된다. 본 발명에서는 상기와 같이 슬라브의 평균 냉각속도를 제어하기 위한 수단에 대해서는 특별히 한정하지 않으나, 예를 들면, 연주 스트랜드에 보온재를 설치하는 등의 방법을 들 수 있다.
On the other hand, in the present invention, the average cooling rate at a temperature of 1100 to 1200 ° C is 5 ° C / sec or less (excluding 0 ° C / sec) based on the surface temperature of the slab at the time of casting the molten steel, (Exclusive of 0 占 폚 / sec), more preferably not more than 2 占 폚 / sec (exclusive of 0 占 폚 / sec). That is, by controlling the average cooling rate of the slab at a temperature of 1100 to 1200 ° C as much as possible, the present inventors induced the TiN inclusion to precipitate into nuclei as much as possible so that the number of Ti (CN) And that the number of Ti (CN) independent precipitates can be reduced below the target number by cooling the slab under the above conditions. It is presumed that Ti, C and N are diffused around TiN inclusions having high energy and Ti (CN) is precipitated as nuclei because a large amount of Ti, C and N are dispersed around the alloying elements due to slow cooling. In the present invention, the means for controlling the average cooling rate of the slabs as described above is not particularly limited. For example, a method of providing a thermal insulating material on the playing strand can be mentioned.
한편, 상기와 같이 평균 냉각속도를 제어하는 방법은 특별히 한정하지 않으며, 상기의 온도 범위 전 구간에서 일정한 냉각 속도로 서냉하거나, 상기의 온도 구간 내 특정 온도에서 균열 후 빠른 냉각 속도로 급냉하는 방법을 취할 수 있다.
The method of controlling the average cooling rate as described above is not particularly limited, and a method of slowly cooling at a constant cooling rate throughout the temperature range described above, or quenching at a specific cooling rate within a predetermined temperature range in the above temperature range I can take it.
한편, 본 발명의 일 구현예에 따르면, 상기와 같이 서냉을 실시하는 온도 범위를 1000~1250℃로 확장함으로써, TiN 개재물의 조대화를 유도하고, 이에 따라 TiN 개재물이 Ti(CN) 석출을 위한 핵생성 사이트로 보다 용이하게 작용함으로써, 그 효과를 보다 극대화할 수 있다.
According to an embodiment of the present invention, the temperature range for slow cooling as described above is extended to 1000 to 1250 DEG C to induce the coarsening of TiN inclusions, whereby TiN inclusions are formed for Ti (CN) precipitation By acting more easily with the nucleation site, the effect can be maximized.
본 발명의 일 구현예에 따르면, 상기 슬라브를 마무리 열간압연하여 열연판을 얻는 단계; 및 상기 열연판을 열연판 소둔하는 단계를 더 포함할 수 있다. 이하, 각각의 공정에 대하여 보다 상세히 설명한다.
According to an embodiment of the present invention, there is provided a method of manufacturing a hot-rolled steel sheet, comprising the steps of: And a step of subjecting the hot-rolled sheet to hot-rolled sheet annealing. Hereinafter, each step will be described in more detail.
열연판 소둔: 450~1080℃의 온도에서 60분 이하 실시Annealing of hot rolled sheet: conducted at a temperature of 450 ~ 1080 ℃ for 60 minutes or less
열연판 소둔은 열간압연된 열연판의 연성을 보다 향상시키기 위해 실시되는 단계로써, 이를 통해 Ti(CN) 독립 석출물의 재용해와 재용해된 합금 원소들의 확산을 유도하여, Ti(CN) 독립 석출물의 개수를 보다 저감할 수 있다. 이를 위해서는 소둔온도를 450℃ 이상에서 실시할 필요가 있다. 다만, 소둔온도가 1080℃를 초과하거나, 소둔시간이 60분을 초과할 경우, Ti(CN) 종속 석출물의 재용해가 일어나 오히려 그 효과가 반감될 우려가 있다. 한편, 소둔시간의 하한은 특별히 정할 필요는 없으나, 충분한 효과를 얻기 위해서는 1분 이상 실시하는 것이 보다 바람직하다.
The hot-rolled sheet annealing is a step carried out to further improve the ductility of the hot-rolled hot-rolled sheet, thereby inducing redissolution of the Ti (CN) independent precipitate and diffusion of the redissolved alloy elements, Can be further reduced. For this purpose, it is necessary to carry out annealing at a temperature of 450 DEG C or higher. However, if the annealing temperature exceeds 1080 占 폚 or the annealing time exceeds 60 minutes, there is a fear that the effect of the Ti (CN) dependent precipitate is redissolved rather than half. On the other hand, although the lower limit of the annealing time is not particularly defined, it is more preferable to carry out the annealing for one minute or longer to obtain a sufficient effect.
제조조건을 상술한 바와 같이 제어하였을 경우 그 외의 특별히 한정하지 않은 조건은, 통상의 페라이트계 스테인리스 강판의 제조조건에 준하여 행할 수 있다. 덧붙여, 상기 소둔된 열연판을 냉간압연 및 냉연판 소둔하여 냉연강판으로도 제조할 수도 있다.
When the production conditions are controlled as described above, other conditions are not particularly limited and can be carried out in accordance with the production conditions of a conventional ferritic stainless steel sheet. In addition, the annealed hot rolled sheet may be cold rolled and cold rolled sheet annealed to produce a cold rolled steel sheet.
이하, 실시예를 통하여 본 발명을 보다 구체적으로 설명한다. 다만, 하기하는 실시예는 본 발명을 예시하여 구체화하기 위한 것일 뿐, 본 발명의 권리범위를 제한하기 위한 것이 아니라는 점에 유의할 필요가 있다. 본 발명의 권리범위는 특허청구범위에 기재된 사항과 이로부터 합리적으로 유추되는 사항에 의하여 결정되는 것이기 때문이다.
Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate and specify the present invention and not to limit the scope of the present invention. And the scope of the present invention is determined by the matters described in the claims and the matters reasonably deduced therefrom.
(( 실시예Example ))
표 1의 조성을 가지는 용강을 준비하고, 표 2에 기재된 조건으로 등속주조하여 슬라브를 제조하고, 제조된 슬라브를 열간압연 및 열연판소둔하여 열연판을 얻었다. 표 1에 기재된 각 원소의 함량은 중량%를 의미하며, 표 2에 기재된 슬라브의 냉각속도는 1100~1200℃의 온도 범위에서 슬라브의 표면온도를 기준으로 측정한 평균 냉각속도를 의미한다.
Molten steel having the composition shown in Table 1 was prepared and cast at a constant speed according to the conditions shown in Table 2 to prepare slabs. The slabs were subjected to hot rolling and hot-rolled annealing to obtain hot-rolled steel sheets. The content of each element shown in Table 1 means weight%, and the cooling rate of the slab shown in Table 2 means the average cooling rate measured based on the surface temperature of the slab in a temperature range of 1100 to 1200 ° C.
이후, 제조된 각각의 냉연판에 대하여 투과전자현미경(Transmission Electron Microscope, TEM) 사진을 촬영하고, 이미지 애널라이저(Image Analyzer)를 통해 입경 0.01μm 이상인 Ti(CN) 독립 석출물의 개수 및 개수 비(PS)를 측정하였다. 또한, 상기 냉연판의 압연방향에 대하여 90° 방향을 기준으로 JIS 13B 규격에 의거하여 채취된 시험편을 채취하여, 연신율을 측정하였다. 그 결과를 하기 표 3에 나타내었다.
Each of the prepared cold-rolled sheets was photographed by a transmission electron microscope (TEM), and the number and the number ratio of Ti (CN) -dependent precipitates having a particle diameter of 0.01 탆 or more (P S ) was measured. In addition, a test piece taken in accordance with JIS 13B standard was taken with respect to the rolling direction of the cold-rolled sheet with reference to the 90 占 direction, and the elongation was measured. The results are shown in Table 3 below.
표 3을 참조할 때, 본 발명이 제안하는 조건을 모두 만족하는 발명예 1 내지 3의 경우, Ti(CN) 독립 석출물의 개수가 3.5×106개/mm2 이하로 억제되어 연신율 34% 이상의 우수한 연성을 확보할 수 있음을 알 수 있다. 반면, 비교예 1 및 2의 경우, 슬라브의 냉각이 상대적으로 빠르게 진행되어 Ti(CN) 독립 석출물이 과다하게 형성되어 연성이 열화되었음을 알 수 있다.
In the case of Inventive Examples 1 to 3, which satisfy all of the conditions proposed by the present invention, the number of Ti (CN) independent precipitates is suppressed to 3.5 x 10 6 / mm 2 or less, It can be seen that excellent ductility can be secured. On the other hand, in the case of Comparative Examples 1 and 2, it can be seen that the cooling of the slab progressed relatively quickly, and excessive formation of the Ti (CN) independent precipitate deteriorated the ductility.
한편, 도 1은 발명예 1에 따른 열연판의 미세조직을 관찰한 전자현미경(Scanning Electron Microscope, SEM) 사진이고, 도 2는 도 1의 A 영역을 확대하여 관찰한 전자현미경(Scanning Electron Microscope, SEM) 사진이다. 도 1의 A 영역의 가운데에 위치하고 있는 것이 제강에서 정출된 TiN 개재물에 해당하는데, 이를 확대하여 관찰한 도 2를 참조하면, 상기 TiN 개재물을 핵으로 하여 다량의 Ti(CN)이 석출되어 있음을 시각적으로 확인할 수 있다.1 is a scanning electron microscope (SEM) photograph of a microstructure of a hot-rolled sheet according to Inventive Example 1. FIG. 2 is a scanning electron microscope (SEM) SEM) picture. FIG. 2 is an enlarged view of the TiN inclusions formed in the center of the region A in FIG. 1, and a large amount of Ti (CN) precipitates from the TiN inclusion as nuclei It can be confirmed visually.
Claims (10)
페라이트 기지에, 3.5×106개/mm2 이하의 Ti(CN) 독립 석출물을 포함하는 페라이트계 스테인리스 강재.
0.005 to 0.1% of Si, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% or less of P, 0.005% or less of S, 10 to 30% of Cr, 0.005 to 0.5% of Ti, 0.01 to 0.15% of Al, 0.005 to 0.03% of N, the balance Fe and unavoidable impurities,
A ferritic stainless steel material containing a Ti (CN) independent precipitate of 3.5 x 10 6 / mm 2 or less on a ferrite base.
페라이트 기지에, Ti(CN) 독립 석출물과 TiN 개재물을 핵으로 하여 석출된 Ti(CN) 종속 석출물을 포함하고, 하기 식 1로 정의되는 PS가 60% 이하인 페라이트계 스테인리스 강재.
[식 1]
PS(%)={NS/(NS+NC)} × 100
(여기서, NS는 Ti(CN) 독립 석출물의 단위 면적 당 개수(개/mm2)이며, NC는 Ti(CN) 종속 석출물의 단위 면적 당 개수(개/mm2)를 의미함)
0.005 to 0.1% of Si, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% or less of P, 0.005% or less of S, 10 to 30% of Cr, 0.005 to 0.5% of Ti, 0.01 to 0.15% of Al, 0.005 to 0.03% of N, the balance Fe and unavoidable impurities,
A ferritic stainless steel material comprising a Ti (CN) independent precipitate and a Ti (CN) dependent precipitate precipitated with a TiN inclusion as nuclei in the ferrite base, wherein the P S defined by the following formula 1 is 60% or less.
[Formula 1]
P S (%) = {N S / (N S + N C )} × 100
(Where N S is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 ) and N C is the number of Ti (CN) -dependent precipitates per unit area (number / mm 2 )
상기 PS가 58% 이하인 페라이트계 스테인리스 강재.
3. The method of claim 2,
Wherein the P S is 58% or less.
상기 Ti(CN) 독립 석출물의 입경은 0.01μm 이상인 페라이트계 스테인리스 강재.
3. The method according to claim 1 or 2,
Wherein the Ti (CN) independent precipitate has a grain size of 0.01 탆 or more.
상기 Ti(CN) 독립 석출물의 평균 입경은 0.15μm 이하인 페라이트계 스테인리스 강재.
3. The method according to claim 1 or 2,
Wherein said Ti (CN) independent precipitate has an average grain size of 0.15 탆 or less.
상기 TiN 개재물의 평균 입경은 2μm 이상인 페라이트계 스테인리스 강재.
3. The method of claim 2,
Wherein the average particle diameter of the TiN inclusions is 2 占 퐉 or more.
상기 스테인리스 강재의 연신율은 34% 이상인 페라이트계 스테인리스 강재.
3. The method according to claim 1 or 2,
And the elongation of the stainless steel is at least 34%.
상기 용강의 주조시, 상기 슬라브의 표면 온도를 기준으로 1100~1200℃의 온도에서의 평균 냉각속도를 5℃/sec 이하(0℃/sec 제외)로 제어하는 것을 특징으로 하는 페라이트계 스테인리스 강재의 제조방법.
0.005 to 0.1% of Si, 0.01 to 2.0% of Si, 0.01 to 1.5% of Mn, 0.05% or less of P, 0.005% or less of S, 10 to 30% of Cr, 0.005 to 0.5% of Ti, , Al: 0.01 to 0.15%, N: 0.005 to 0.03%, and the balance Fe and unavoidable impurities, in a slab of a ferritic stainless steel material,
Wherein an average cooling rate at a temperature of 1100 to 1200 占 폚 is controlled to 5 占 폚 / sec or less (excluding 0 占 폚 / sec) based on the surface temperature of the slab at the time of casting the molten steel. Gt;
상기 용강의 주조시, 상기 슬라브의 표면 온도를 기준으로 1000~1250℃의 온도에서의 평균 냉각속도를 5℃/sec 이하(0℃/sec 제외)로 제어하는 것을 특징으로 하는 페라이트계 스테인리스 강재의 제조방법.
9. The method of claim 8,
Wherein an average cooling rate at a temperature of 1000 to 1250 占 폚 is controlled to 5 占 폚 / sec or less (excluding 0 占 폚 / sec) based on the surface temperature of the slab during casting of the molten steel. Gt;
상기 용강을 슬라브로 주조 후,
상기 슬라브를 재가열하는 단계;
상기 재가열된 슬라브를 열간압연하여 열연강재를 얻는 단계; 및
상기 열연강재를 450~1080℃의 온도에서 60분 이하 동안 열연판 소둔하는 단계를 더 포함하는 페라이트계 스테인리스 강재의 제조방법.9. The method of claim 8,
After casting the molten steel into a slab,
Reheating the slab;
Hot-rolling the reheated slab to obtain a hot-rolled steel; And
Further comprising the step of annealing the hot-rolled steel sheet at a temperature of 450 to 1080 DEG C for 60 minutes or less in the hot-rolled steel sheet.
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| PCT/KR2015/004410 WO2016104883A1 (en) | 2014-12-26 | 2015-04-30 | Ferritic stainless steel material having superb ductility and method for producing same |
| US15/529,263 US20170283894A1 (en) | 2014-12-26 | 2015-04-30 | Ferritic stainless steel having excellent ductility and method for manufacturing same |
| JP2017533577A JP6605032B2 (en) | 2014-12-26 | 2015-04-30 | Ferritic stainless steel material excellent in ductility and its manufacturing method |
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| WO2018062617A1 (en) * | 2016-09-28 | 2018-04-05 | 주식회사 포스코 | Ferritic stainless steel having reduced carbon sludge adsorption for exhaust system heat exchanger and method of manufacturing same |
| CN109415783A (en) * | 2016-03-30 | 2019-03-01 | 日新制钢株式会社 | Ferrite series stainless steel plate containing Ti and manufacturing method and flange |
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| KR102020511B1 (en) | 2017-12-14 | 2019-09-10 | 주식회사 포스코 | Ferritic stainless steel with excellent impact toughness and manufacturing method thereof |
| KR102123665B1 (en) * | 2018-10-23 | 2020-06-18 | 주식회사 포스코 | High-strength ferritic stainless steel for clamp and method for manufacturing the same |
| CN109648064B (en) * | 2019-01-25 | 2021-04-20 | 北京科技大学 | Method for realizing sigma phase transformation of super austenitic stainless steel solidification structure |
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| JP2005307234A (en) * | 2004-04-19 | 2005-11-04 | Nisshin Steel Co Ltd | Ferritic stainless steel sheet having excellent ridging resistance and surface characteristic and method for manufacturing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109415783A (en) * | 2016-03-30 | 2019-03-01 | 日新制钢株式会社 | Ferrite series stainless steel plate containing Ti and manufacturing method and flange |
| EP3438308A4 (en) * | 2016-03-30 | 2019-09-25 | Nippon Steel Nisshin Co., Ltd. | Ti-containing ferritic stainless steel sheet, manufacturing method, and flange |
| CN109415783B (en) * | 2016-03-30 | 2021-02-12 | 日铁不锈钢株式会社 | Ti-containing ferritic stainless steel sheet, method for producing same, and flange |
| WO2018062617A1 (en) * | 2016-09-28 | 2018-04-05 | 주식회사 포스코 | Ferritic stainless steel having reduced carbon sludge adsorption for exhaust system heat exchanger and method of manufacturing same |
| EP3521471A4 (en) * | 2016-09-28 | 2019-09-04 | Posco | Ferritic stainless steel having reduced carbon sludge adsorption for exhaust system heat exchanger and method of manufacturing same |
| US11634801B2 (en) | 2016-09-28 | 2023-04-25 | Posco Co., Ltd | Ferritic stainless steel having reduced carbon sludge adsorption for exhaust system heat exchanger and method of manufacturing same |
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| EP3239335B1 (en) | 2019-11-13 |
| EP3239335A1 (en) | 2017-11-01 |
| ES2767505T3 (en) | 2020-06-17 |
| WO2016104883A8 (en) | 2017-01-19 |
| CN107109598A (en) | 2017-08-29 |
| WO2016104883A1 (en) | 2016-06-30 |
| CN107109598B (en) | 2018-09-14 |
| EP3239335A4 (en) | 2017-11-29 |
| US20170283894A1 (en) | 2017-10-05 |
| JP6605032B2 (en) | 2019-11-13 |
| JP2018505308A (en) | 2018-02-22 |
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