KR100431435B1 - Method for Preventing Surface Cracks of Ferritic Stainless Steel During Hot Rolling Process - Google Patents
Method for Preventing Surface Cracks of Ferritic Stainless Steel During Hot Rolling Process Download PDFInfo
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- KR100431435B1 KR100431435B1 KR10-1999-0040081A KR19990040081A KR100431435B1 KR 100431435 B1 KR100431435 B1 KR 100431435B1 KR 19990040081 A KR19990040081 A KR 19990040081A KR 100431435 B1 KR100431435 B1 KR 100431435B1
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- rolling
- stainless steel
- hot
- ferritic stainless
- slab
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- 238000005098 hot rolling Methods 0.000 title claims abstract description 27
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims abstract description 9
- 238000005096 rolling process Methods 0.000 claims abstract description 68
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000011651 chromium Substances 0.000 claims abstract description 11
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 9
- 238000003303 reheating Methods 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 230000007547 defect Effects 0.000 abstract description 15
- 238000005336 cracking Methods 0.000 abstract description 8
- 238000005498 polishing Methods 0.000 abstract description 4
- 239000002344 surface layer Substances 0.000 description 11
- 229910000859 α-Fe Inorganic materials 0.000 description 11
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 229910001566 austenite Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000002547 anomalous effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- -1 ferritic Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/16—Control of thickness, width, diameter or other transverse dimensions
-
- 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
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2201/00—Special rolling modes
- B21B2201/04—Ferritic rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2265/00—Forming parameters
- B21B2265/14—Reduction rate
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Rolling (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
페라이트계 스테인레스강의 열간 압연 중 표면 결함 방지 방법에 관한 것으로, 16 ~ 18% 크롬을 함유하고 니켈을 소량 잔류 원소로 함유한 페라이트계 스테인레스강의 열간 압연 공정에서, 열연 가열로에서 재가열한 후, 조압연의 첫 번째 압연인 R1의 압하율은 10% 이하이고, 두 번째 압연인 R2의 첫 패스 압하율을 18% 이하로 설정하여 생산함으로써, 열연 스트립의 표면에 발생하는 표면 크랙성 결함을 감소하게 함으로써, 결함 제거를 위한 스트립 연마 공정이 필요 없게 된다.The present invention relates to a method for preventing surface defects during hot rolling of ferritic stainless steel, wherein the hot rolling process of ferritic stainless steel containing 16 to 18% chromium and a small amount of nickel as a residual element is performed after reheating in a hot rolling furnace, followed by rough rolling. The rolling reduction of R1, which is the first roll of, is less than 10%, and produced by setting the first pass reduction of R2, which is the second rolling, to 18% or less, thereby reducing surface cracking defects occurring on the surface of the hot rolled strip. This eliminates the need for strip polishing to eliminate defects.
Description
본 발명은 스테인레스강의 열연 기술에 관한 것으로, 보다 상세하게는 16 ~ 18% 크롬을 함유하고 니켈을 소량 잔류 원소로 함유한 페라이트계 스테인레스강의 열간 압연 중 표면 결함 방지 방법에 관한 것이다.The present invention relates to a hot rolling technique of stainless steel, and more particularly, to a method for preventing surface defects during hot rolling of ferritic stainless steel containing 16-18% chromium and containing a small amount of residual elements.
일반적으로 스테인레스강은 크게 마르텐사이트계, 페라이트계, 오스테나이트계 및 이상계 4가지로 나눌 수 있는 데, 페라이트계와 오스테나이트계가 전체의 90%를 차지하고 있다.In general, stainless steel can be divided into martensite, ferritic, austenite, and anomalous. The ferritic and austenitic steels account for 90% of the total stainless steel.
페라이트계 스테인레스강은 크롬(Cr)계 스테인레스강의 일종으로 크롬 함량이 12 ∼ 18% 범위이며, 일반적으로 널리 쓰이는 강종으로 AISI 430 및 409 강종이 있다.Ferritic stainless steel is a kind of chromium (Cr) stainless steel with chromium content in the range of 12 to 18%, and commonly used AISI 430 and 409 steel grades.
그리고, 오스테나이트계 스테인레스강은 스테인레스강에 니켈(Ni)이 충분히 첨가되면 결정구조가 오스테나이트로 바뀌기 때문에 오스테나이트계 스테인레스강이라는 용어가 생겨 났으며 기본 조성은 크롬 18%와 니켈 8%로서 18/8 강종으로 불리고 있다.In addition, austenitic stainless steel has the term austenitic stainless steel because the crystal structure is changed to austenite when nickel (Ni) is sufficiently added to the stainless steel, and the basic composition is 18% of chromium and 18% of nickel. It is called / 8 steel grade.
이러한 스테인레스강 열연 공장의 설비는 슬라브 야드(slab yard), 열연 가열로 및 압연 설비, 수냉각 및 권치기, 계산기, 정정설비 등이 있으며, 이밖에도 수처리 설비, 유실 등의 운전 부대 설비가 있다.The facilities of such stainless steel hot rolling mills include slab yards, hot rolled furnaces and rolling equipment, water cooling and winding machines, calculators, and correction equipment. In addition, there are operating facilities such as water treatment facilities and oil chambers.
도 1은 열연 스트립의 압연시 설비 개략도에 관한 것으로, 상기 도면에 따르면 열연용 소재로는 슬라브(slab)(11)를 사용하며, 열연 가열로(12)는 슬라브(11)를 필요한 온도까지 균일하게 가열하는 설비를 말한다.1 is a schematic diagram of a facility for rolling a hot rolled strip. According to the drawings, a slab 11 is used as a material for hot rolling, and the hot rolled furnace 12 uniformly adjusts the slab 11 to a required temperature. It means the equipment to be heated.
압연 공정은 소재를 회전하는 2개의 롤(roll) 사이를 통과시켜 원하는 치수, 형상과 제품을 만드는 것으로 두께가 두꺼운 소재를 바로 얇은 최종 제품의 사이즈로 압연하기가 어렵다.The rolling process passes the material between two rolls to create the desired dimensions, shape and product, making it difficult to roll thick material directly into the size of the thin end product.
따라서, 압연 공정은 크게 조압연 구간(13)과 사상압연 구간(15)으로 나누어 작업하게 되는 데 조압연 구간(13)에서는 많은 양의 두께와 폭 압연을 통해 최종마무리를 위한 1 차적 압연을 하고, 이렇게 만들어진 소재를 바(bar)(14)라 하며 사상압연 구간(15)에서 최종 마무리를 하는 개념으로 압연한 후, 최종 사상압연기(15)를 통과한 스트립(6)을 코일 모양으로 감는다.Therefore, the rolling process is largely divided into rough rolling section 13 and finishing rolling section 15. In the rough rolling section 13, primary rolling for final finishing is performed by rolling a large amount of thickness and width. The rolled strip 6 passed through the final finishing mill 15 is wound into a coil shape after rolling the material thus made, called a bar 14, in the finishing finishing section 15.
상기 조압연 구간(13)에서 압연 순서에 대해 상술하면, 열연 가열로(12)에서 축출한 슬라브(11)를 순차적으로 R1, R2(1패스), R2(2패스), R2(3패스), R3, R4 압연롤을 통과하여 원하는 바(bar)(14)를 만든다. 여기서, R1, R3, R4 압연롤은 순방향의 압연기이고, R2는 순방향, 역방향 왕복 압연기이다.In the rough rolling section 13, the rolling order is described in detail. The slabs 11 evicted from the hot rolling furnace 12 are sequentially R1, R2 (1 pass), R2 (2 pass), and R2 (3 pass). , R3, R4 through the rolling roll to make the desired bar (14). Here, R1, R3 and R4 rolling rolls are forward rolling mills, and R2 is forward and reverse reciprocating rolling mills.
한편, 도 2는 열연 가열로(12)에서의 STS430 강의 슬라브(11) 단면 관찰 사진에 관한 것으로, 배율을 10배로 하였다.In addition, FIG. 2 is related with the cross-sectional observation photograph of the slab 11 of STS430 steel in the hot-rolling furnace 12, and magnification was made 10 times.
상기 도면에 의하면, 통상의 크롬을 함유하고 니켈을 소량 잔류 원소로 함유한 페라이트계 스테인레스강의 슬라브(11)를 1250℃ 정도로 열간 압연시에 슬라브(11) 표층부는 고온 산화성 분위기 하에서 표면에 탈탄 등에 의하여 슬라브 표층부(21)에 페라이트 단상 조직이 가열 온도 및 성분에 따라 2 ~ 5mm 생성되고 그 하부에 페라이트와 오스테나이트 혼상 조직(22)이 생성된다.According to the drawing, when the hot-rolled slab 11 of ferritic stainless steel containing ordinary chromium and a small amount of nickel as a residual element at about 1250 ° C., the surface layer portion of the slab 11 is decarburized on the surface under a high temperature oxidizing atmosphere. In the slab surface layer portion 21, a ferrite single phase structure is generated 2 to 5 mm depending on the heating temperature and the components, and a ferrite and austenite mixed structure 22 is formed at the bottom thereof.
이와 같이 페라이트계 스테인레스강은 화학 성분의 특성상 페라이트와 오스테나이트 혼상 조직에서 압연이 되므로 페라이트 조직과 페라이트와 오스테나이트의 혼상 조직간의 가공성의 차이에 의한 열간 가공성이 오스테나이트계 스테인레스에 비하여 열위한 문제점이 있다.As such, ferritic stainless steel is rolled in the ferrite and austenite mixed phase due to the chemical properties, so the hot workability due to the difference in workability between the ferrite structure and the mixed structure of the ferrite and austenite has a problem for heat compared to the austenitic stainless steel. have.
한편, 종래의 압연 공정은 고온인 초기 압연시에 압하율을 높여 압연함으로써 온도가 떨어지는 다음 압연 공정(R2 이후)에서 롤의 압연 부하를 줄이는 것으로설정되어 있으며, 이때에 표층에서 롤과의 마찰이 가장 크므로 크랙의 발생이 용이하게 되고, 특히 온도가 높으면 슬라브 표층부의 페라이트 단상(21) 조직의 두께가 두꺼워져 크랙 발생이 용이하여 발생된 크랙이 R2 이후에서도 제거되지 않고 열연 스트립(16)에 결함이 잔존하므로 결함을 제거하기 위하여 스트립 연마 공정이 추가로 필요하게 된다.On the other hand, the conventional rolling process is set to reduce the rolling load of the roll in the next rolling process (after R2) when the temperature is lowered by increasing the rolling reduction rate during the initial rolling at a high temperature, whereby friction with the roll in the surface layer is reduced. Since it is the largest, it is easy to generate cracks. Especially, if the temperature is high, the thickness of the ferrite single phase 21 structure of the slab surface layer becomes thick, so that cracks are easily generated. As the defects remain, an additional strip polishing process is needed to remove the defects.
본 발명은 이와 같은 문제점을 해결하기 위하여 안출한 것으로, 그 목적은 페라이트계 스테인레스강의 열간 압연 중 조압연 초기에 크랙이 발생하지 않을 정도로 낮은 압하율로 압연을 실시함으로써, 슬라브 조질의 열간 가공성의 차이로 인한 크랙성 표면 결함의 발생을 방지하는 방법을 제공한다.The present invention has been made to solve the above problems, and its object is to perform rolling at a low rolling rate such that cracks do not occur at the initial stage of rough rolling during hot rolling of ferritic stainless steel, thereby resulting in a difference in hot workability of slab quality. It provides a method for preventing the occurrence of cracked surface defects caused by.
도 1은 열연 스트립의 압연시 설비 개략도,1 is a schematic view of the installation in the rolling of a hot rolled strip,
도 2는 열연 가열로에서의 STS430 강의 슬라브 단면 관찰 사진,2 is a sectional view of the slab cross section of the STS430 steel in the hot-rolling furnace,
도 3은 STS430강의 슬라브 조건에 따른 단면 연신율에 의한 열간 가공성을 평가한 결과를 나타낸 그래프,3 is a graph showing the results of evaluating hot workability by the cross-sectional elongation according to slab conditions of STS430 steel,
도 4는 열간 압연시 재가열 온도 및 조압연 R1, R2 압연롤의 압하율, 압하량에 따른 표면 크랙성 결함 발생에 의한 열연 스트립의 연마 보수율 추이를 나타낸 그래프이다.4 is a graph showing the polishing repair rate of the hot rolled strip due to the reheating temperature during the hot rolling, the rolling reduction ratio of the rough rolling R1 and R2 rolling rolls, and the occurrence of surface cracking defects according to the rolling reduction.
상기와 같은 목적을 달성하기 위하여, 본 발명은 16 ~ 18% 크롬을 함유하고 니켈을 소량 잔류 원소로 함유한 페라이트계 스테인레스강의 열간 압연 공정에서, 열연 가열로에서 재가열한 후, 조압연의 첫 번째 압연인 R1의 압하율은 10% 이하이고, 두 번째 압연인 R2의 첫 패스 압하율을 18% 이하로 설정하여 생산한다.In order to achieve the above object, the present invention, in the hot rolling process of ferritic stainless steel containing 16-18% chromium and containing a small amount of residual elements, after reheating in a hot-rolling furnace, the first of the rough rolling The rolling reduction of R1, which is rolled, is 10% or less, and is produced by setting the first pass reduction of R2, which is the second rolling, to 18% or less.
이하, 본 발명을 보다 상세히 설명한다.Hereinafter, the present invention will be described in more detail.
도 3은 STS430강의 슬라브 조건에 따른 단면 연신율에 의한 열간 가공성을 평가한 결과를 나타낸 그래프이고, 도 4는 열간 압연시 재가열 온도 및 조압연 R1, R2 압연롤의 압하율, 압하량에 따른 표면 크랙성 결함 발생에 의한 열연 스트립의 연마 보수율 추이를 나타낸 그래프이다.3 is a graph showing the results of the evaluation of hot workability by the cross-sectional elongation according to the slab conditions of STS430 steel, Figure 4 is the reheating temperature during hot rolling and the surface cracking according to the reduction rate, rolling reduction of the rough rolling R1, R2 rolling rolls It is a graph showing the trend of polishing repair rate of hot rolled strip due to the generation of defects.
도 3에 도시된 바와 같이, 열간 가공성은 슬라브(31)와 바(bar)(32) 사이에 열간 가공성 차이가 발생되며, STS430 슬라브(31) 상태보다 열간 압연을 한번 이상 행한 STS430 바(bar)(32)에서의 열간 가공성이 매우 우수함을 보여준다. 그리고, 슬라브를 열간 압연시에 이러한 열간 가공성 차이 이외에 슬라브 표층부의 페라이트 단상(21)의 존재는 열간 가공성 차이에 영향을 미친다. 여기서, STS430 바(bar)는 슬라브를 200mm에서 35mm까지 열간 압연 후 재가열하여 열간 가공성을 평가한 것이다.As shown in Figure 3, the hot workability is a difference between the hot workability between the slab 31 and the bar (32) occurs, STS430 bar (hot) that has been subjected to hot rolling more than once than the STS430 slab 31 state It is shown that the hot workability in (32) is very excellent. The presence of the ferrite single phase 21 in the slab surface layer portion affects the hot workability difference in addition to the hot workability difference in hot rolling of the slab. Here, STS430 bar (bar) is to evaluate the hot workability by reheating the slab after hot rolling from 200mm to 35mm.
또한, 재가열한 STS430 슬라브(33)는 전 온도 범위에 열가공성이 매우 우수함을 보여 주었다.In addition, the reheated STS430 slab 33 showed that the thermal workability is very excellent over the entire temperature range.
도 4에 도시된 바와 같이, 종래의 조건인 조압연 구간(13)의 R1 및 R2 첫 패스에서 강압하를 실시한 경우에는 열간 압연롤과 슬라브(11)의 계면에서 마찰이 가장 심하므로 슬라브(11)의 표층부에서의 페라이트 단상 조직(21)과 페라이트와 오스테나이트 혼상 조직(22)의 열간 가공성 차이에 의하여 표층부에서 크랙 발생이 용이하여 표면 크랙성 결함에 의하여 열연 스트립의 연마 보수율이 매우 높게 나타나고 있다.As shown in FIG. 4, when the step is performed in the first pass of R1 and R2 of the rough rolling section 13 which is a conventional condition, the slab 11 has the highest friction at the interface between the hot rolling roll and the slab 11. Due to the difference in the hot workability between the ferrite single phase structure 21 and the ferrite and austenite mixed phase structure 22 at the surface layer portion of), cracks are easily generated at the surface layer portion, and the polishing repair rate of the hot rolled strip is very high due to surface cracking defects. .
이를 개선하기 위하여, STS430 강종(16.2%:Cr, 0.05%:C, 0.04%:N, 0.4%:Si, 0.5%:Mn, 0.2%:Ni)을 열간 압연시에 슬라브 압연의 첫 번째 압연 공정인 조압연 R1에서 압하율을 종래의 16%에서 8%로 낮추고, 그 다음 압연 공정인 조압연 R2 첫 패스에서는 압하율을 종래의 20 ~ 24%에서 16%로 낮추면 표면 크랙성 결함이 현저하게 감소한다.To improve this, the first rolling process of slab rolling during hot rolling of STS430 steel grades (16.2%: Cr, 0.05%: C, 0.04%: N, 0.4%: Si, 0.5%: Mn, 0.2%: Ni) In the rough rolling R1, the reduction ratio was reduced from 16% to 8% in the conventional rolling process, and the rolling reduction ratio in the first pass of the rough rolling R2 was lowered to 16% from the conventional 20 to 24%. Decreases.
특히, 조압연 R1의 압하율만 16%에서 8%로 낮추고 다음 공정인 조압연 R2 첫 패스의 압하율은 종래의 동일 수준의 20 ~ 24%로 유지하여 압연하면 테스트 1과 2에서와 같이 표면 크랙성 결함의 발생율은 감소하지만 완전히 개선하기가 어려우나 R1과 R2 첫 패스의 압하율을 동시에 낮추는 본 발명의 압연 방법에서 표면 크랙성 결함의 개선에 매우 효과적인 것으로 나타났다.In particular, if only the rolling reduction rate of rough rolling R1 is reduced from 16% to 8% and the rolling reduction of the first pass of the rough rolling R2, which is the next process, is maintained at 20 to 24% of the same level as before, rolling Although the incidence of cracking defects is reduced but difficult to fully improve, it has been shown to be very effective in improving surface cracking defects in the rolling method of the present invention which simultaneously lowers the reduction ratio of R1 and R2 first pass.
이것은 도 3에서와 같이, 슬라브 표층부의 페라이트 단상 조직이(21) 슬라브 초기 압연시 압하율이 높으면 슬라브 조직은 큰 연주 조직을 그대로 가지고 있으므로 열간 가공성이 나빠 표층부의 크랙 발생이 쉽게 되나, STS430 바(bar)(32)는 열간 가공성에 의해 슬라브 조직이 압연에 의해 특히 롤과의 마찰에 의해 압연 가공을 가장 많이 받는 표층부는 미세하고 가공성이 좋은 압연 조직으로 바뀌므로 슬라브에 비하여 열간 가공성이 좋은 것으로 알 수 있다.As shown in FIG. 3, if the ferrite single-phase structure of the slab surface layer 21 has a high rolling reduction rate at the initial rolling of the slab, the slab structure has a large playing structure as it is, so that hot workability is poor and cracks are easily generated at the surface layer portion. bar) (32) shows that the hot workability is better than that of the slab because the surface layer portion where the slab structure is subjected to the rolling process by hot workability, in particular by friction with the roll, is changed to a fine and workable rolling structure. Can be.
또한, 도 4에서와 같이, STS430 강종을 실제 압연 결과에서 보듯이 조압연 첫 패스인 R1에서의 압하율 및 R2 첫 패스에서의 압하율을 동시에 낮추면 종래에 비하여 크랙성 표면 결함이 매우 감소하는 것을 알 수 있다.In addition, as shown in Figure 4, as shown in the actual rolling results of the STS430 steel sheet at the same time lowering the reduction rate in the first pass of the rough rolling R1 and the first pass of the R2 at the same time it is significantly reduced cracking surface defects compared to the conventional Able to know.
특히, 온도가 높으면 슬라브 표층부의 페라이트 단상 조직의 두께가 두꺼워져 크랙 발생이 용이하므로 실제 열연 작업시 온도 변동폭을 감안한다면 본 발명은 온도에 대한 영향도 최소화 할 수 있는 압연 방법이다.Particularly, if the temperature is high, the thickness of the ferrite single-phase structure of the slab surface layer becomes thick, so that cracks are easily generated. Therefore, the present invention is a rolling method that can minimize the influence on temperature in consideration of the temperature fluctuation during the actual hot rolling operation.
이와 같이 본 발명은 크롬을 16 ~ 18% 함유한 페라이트계 스테인레스강은 열간 압연시 R1과 R2에서 압하율을 낮추어 열간 압연 온도의 영향을 최소화하여 열연스트립의 표면에 발생하는 표면 크랙성 결함을 감소하게 함으로써, 결함 제거를 위한 스트립 연마 공정이 필요 없게 된다.As such, the present invention reduces the surface cracking defects occurring on the surface of the hot rolled strip by minimizing the influence of the hot rolling temperature by reducing the rolling reduction ratio in R1 and R2 during hot rolling of the ferritic stainless steel containing 16 to 18% of chromium. This eliminates the need for a strip polishing process for removing defects.
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| KR101230126B1 (en) * | 2009-12-29 | 2013-02-05 | 주식회사 포스코 | Manufacturing method of hot-rolled ferritic stainless steel sheet without edge crack |
| KR200479419Y1 (en) | 2014-06-19 | 2016-01-27 | 삼성중공업 주식회사 | Connector |
| KR102034448B1 (en) * | 2017-12-20 | 2019-10-18 | 주식회사 포스코 | Steel and method for the same |
| CN110686971B (en) * | 2019-10-14 | 2020-10-30 | 中国科学院武汉岩土力学研究所 | Method for accurately judging cracking stress and cracking type of fractured rock mass |
| CN115874017B (en) * | 2022-12-27 | 2024-05-14 | 东北大学 | Method for reducing hot rolling cracks of super duplex stainless steel |
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| JPH0820844A (en) * | 1994-07-05 | 1996-01-23 | Kawasaki Steel Corp | Ferritic stainless steel sheet excellent in workability and its production |
| JPH09155407A (en) * | 1995-12-07 | 1997-06-17 | Sumitomo Metal Ind Ltd | Manufacture of ferritic stainless steel sheet excellent in r value |
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| JPH0820844A (en) * | 1994-07-05 | 1996-01-23 | Kawasaki Steel Corp | Ferritic stainless steel sheet excellent in workability and its production |
| JPH09155407A (en) * | 1995-12-07 | 1997-06-17 | Sumitomo Metal Ind Ltd | Manufacture of ferritic stainless steel sheet excellent in r value |
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