KR100782760B1 - Method for manufacturing cold-rolled steel sheet and galvanized steel sheet having yield ratio and high strength - Google Patents
Method for manufacturing cold-rolled steel sheet and galvanized steel sheet having yield ratio and high strength Download PDFInfo
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- KR100782760B1 KR100782760B1 KR1020060130481A KR20060130481A KR100782760B1 KR 100782760 B1 KR100782760 B1 KR 100782760B1 KR 1020060130481 A KR1020060130481 A KR 1020060130481A KR 20060130481 A KR20060130481 A KR 20060130481A KR 100782760 B1 KR100782760 B1 KR 100782760B1
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- 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
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- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
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- 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
Abstract
Description
본 발명은 자동차용 내판재 멤버류 등의 구조부재로 사용되는 강판의 제조방법에 관한 것으로서, 보다 상세하게는 항복강도 300MPa급 이상의 고 항복비형 고 강도 강판 및 도금강판의 제조방법에 관한 것이다.The present invention relates to a method for manufacturing a steel sheet used as a structural member such as automobile inner member, and more particularly, to a method for manufacturing a high yield ratio type high strength steel sheet and a plated steel sheet having a yield strength of 300 MPa or more.
최근, 자동차의 충격 안전성 규제가 확산되면서 차체의 내충격성 향상을 위하여 멤버(Member), 빔(Beam) 및 필라(Pillar)등의 구조 부재에는 석출경화형 고강도 강판의 적용이 널리 이용되고 있다. Recently, as the impact safety regulations of automobiles have spread, application of precipitation hardening type high strength steel sheets has been widely applied to structural members such as members, beams, and pillars in order to improve impact resistance of a vehicle body.
석출경화형 고강도강판은 자동차의 충돌에너지를 흡수하기 위하여 설계되기 때문에 인장강도(TS) 대비 항복강도(YS)가 높은 즉, 항복비(YS/TS)가 높은 것을 특징으로 하고 있다. Precipitation hardening high-strength steel sheet is designed to absorb the collision energy of the vehicle, characterized in that the yield strength (YS) is high compared to the tensile strength (TS), that is, the yield ratio (YS / TS) is high.
이는 자동차 충돌시 충격에너지 흡수라는 측면에서 내충격성 향상을 위한 강판 두께 증가뿐만 아니라 고항복비형 고강도강의 재료가 요구되기 때문이다.This is because the material of high yield ratio type high strength steel as well as the increase in the thickness of the steel sheet to improve the impact resistance in the aspect of shock energy absorption in the automobile crash is required.
한편, 이러한 석출강화형 고강도강은 주로 Cu, Nb, Ti, V등과 같은 탄,질화물 형성 원소 첨가에 의한 석출강화 효과에 의해 강도를 향상시키는 강으로, 낮은 제조원가로 고강도화를 쉽게 이룰 수 있다. On the other hand, the precipitation-reinforced high-strength steel is mainly a steel to improve the strength by the precipitation strengthening effect by the addition of carbon, nitride forming elements such as Cu, Nb, Ti, V, etc., it is possible to easily achieve high strength at low manufacturing costs.
대표적인 것으로 일본 공개특허공보 2001-115210호, 일본 공개특허공보 평3-140412 및 일본 공개특허공보 평11-241119호가 있다. Representative examples include Japanese Laid-Open Patent Publication No. 2001-115210, Japanese Laid-Open Patent Publication No. Hei 3-140412, and Japanese Laid-Open Patent Publication No. Hei 11-241119.
일본 공개특허공보 2001-115210호에는 저탄소강에 Ti 및 Nb를 적절히 첨가하여 Ar3 변태점 이상의 온도에서 열간 압연 후 10℃/sec이상의 냉각속도로 냉각하여 다시 400~700℃ 부근으로 재가열함으로써 인장강도 590MPa이상의 고강도강판을 제조하는 기술이 개시되어 있다. Japanese Laid-Open Patent Publication No. 2001-115210 discloses that by appropriately adding Ti and Nb to low carbon steel, hot rolling at a temperature above Ar 3 transformation point, cooling at a cooling rate of 10 ° C./sec or more, and reheating to around 400 to 700 ° C., the tensile strength is 590 MPa. The technique for manufacturing the above high strength steel sheet is disclosed.
그러나, 일본 공개특허공보 2001-115210호에서와 같이 Ti 및 Nb 첨가량이 많은 경우에는 Ti 및 Nb에 의한 재결정 온도가 상승함에 따라 소둔 후 코일길이별 재질 편차 발생 가능성이 높을 뿐만 아니라 도금강판 제조시 합금화 불량 발생 가능성이 매우 높다는 문제를 안고 있다.However, as in Japanese Laid-Open Patent Publication No. 2001-115210, when the amount of Ti and Nb added is large, as the recrystallization temperature by Ti and Nb increases, the possibility of material deviation by coil length after annealing is high, and alloying is performed when manufacturing plated steel sheet. The problem is that there is a high possibility of defects.
한편, 일본 공개특허공보 평3-140412호 및 일본 공개특허공보 평11-241119호에는 Cu석출물을 이용한 석출강화형 고강도강판 제조방법으로, Cu를 0.8중량% 이상 첨가하여 제조하는 기술이 제시되어 있다.On the other hand, Japanese Patent Laid-Open Nos. Hei 3-140412 and Japanese Patent Laid-Open No. Hei 11-241119 disclose a technique for producing a precipitation-reinforced high strength steel sheet using Cu precipitates and adding 0.8 wt% or more of Cu. .
그러나, 이 역시 Cu계 석출물에 의한 도금 강판의 합금화 불량 및 용접성에 문제가 있어 현장 적용에 문제점을 안고 있다. However, this also has problems in poor alloying and weldability of the plated steel sheet by the Cu-based precipitates have problems in the field application.
본 발명자는 상기한 종래기술의 문제점을 개선시키기 위하여 연구 및 실험을 행하고, 그 결과에 근거하여 본 발명을 제안하게 된 것으로서, 본 발명은 석출강화와 고용강화를 동시에 확보함으로써 항복강도 편차가 적은 고항복비형 고강도 냉연강판 및 도금강판의 제조방법을 제공하고자 하는데, 그 목적이 있다. The present inventors have conducted research and experiments to improve the above problems of the prior art, and based on the results, the present invention proposes the present invention. It is intended to provide a method of manufacturing a yield ratio high strength cold rolled steel plate and a plated steel sheet, and an object thereof is provided.
이하, 본 발명에 대하여 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.
본 발명은 중량%로 C:0.06~0.08%, Mn:0.55~0.65%, Si: 0.07-0.13%, P:0.03%이하, S:0.01%이하, N:0.006%이하, 산가용 Al:0.02~0.05%, Nb:0.010~0.025%, 나머지 Fe 및 기타 불가피한 불순물로 조성되는 강 슬라브를 1150 ∼ 1220℃로 가열하여 870∼ 910℃에서 열간마무리압연하고, 540∼ 620℃의 온도 범위에서 권취를 행한 다음, 50%이상의 압하율로 냉간압연하여 냉연강판을 제조하고, 760~810℃의 온도범위에서 재결정소둔한 후, 1.2∼1.6%의 압하율로 조질압연하는 것을 특징으로 하는 고강도 냉연간판의 제조방법에 관한 것이다.In the present invention, C: 0.06 ~ 0.08%, Mn: 0.55 ~ 0.65%, Si: 0.07-0.13%, P: 0.03% or less, S: 0.01% or less, N: 0.006% or less, acid value Al: 0.02 Steel slab composed of ˜0.05%, Nb: 0.010˜0.025%, remaining Fe and other unavoidable impurities is heated to 1150 to 1220 ° C., hot rolled at 870 to 910 ° C., and wound up in a temperature range of 540 to 620 ° C. After the cold rolling is carried out at a reduction ratio of 50% or more to produce a cold rolled steel sheet, and after recrystallization annealing at a temperature range of 760 to 810 ° C., temper rolling at 1.2 to 1.6% of the high strength cold rolled sheet. It relates to a manufacturing method.
바람직하게는, 상기 고강도 냉연간판의 제조방법에 있어서, 상기 냉연강판의 두께가 0.6∼1.2mm인 경우에는 열연권취온도: 580∼ 620℃ 및 재결정소둔온도: 770~810℃로 하고; 상기 냉연강판의 두께가 1.2∼1.8mm인 경우에는 열연권취온도: 560∼ 600℃ 및 재결정소둔온도: 770~810℃로 하고; 그리고 상기 냉연강판의 두께가 1.8∼2.5mm인 경우에는 열연권취온도: 540∼ 580℃ 및 재결정소둔온도: 760~800℃로 설정한다.Preferably, in the method of manufacturing the high strength cold rolled steel sheet, when the thickness of the cold rolled steel sheet is 0.6 to 1.2 mm, the hot rolled winding temperature is 580 to 620 ° C and the recrystallization annealing temperature is 770 to 810 ° C; When the cold rolled steel sheet has a thickness of 1.2 to 1.8 mm, hot rolled coiling temperature: 560 to 600 ° C and recrystallization annealing temperature: 770 to 810 ° C; When the thickness of the cold rolled steel sheet is 1.8 to 2.5 mm, the hot rolled coiling temperature is set to 540 to 580 ° C and the recrystallization annealing temperature is set to 760 to 800 ° C.
또한, 본 발명은 중량%로 C:0.06~0.08%, Mn:0.55~0.65%, Si: 0.07-0.13%, P:0.03%이하, S:0.01%이하, N:0.006%이하, 산가용 Al:0.02~0.05%, Nb:0.010~0.025%, 나머 지 Fe 및 기타 불가피한 불순물로 조성되는 강 슬라브를 1150 ∼ 1220℃로 가열하여 870∼ 910℃에서 열간마무리압연하고, 540∼ 620℃의 온도 범위에서 권취를 행한 다음, 50%이상의 압하율로 냉간압연하여 냉연강판을 제조하고, 770~820℃의 온도범위에서 재결정소둔한 후, 용융아연도금하거나 또는 합금화용융아연도금한 다음, 1.0∼1.6%의 압하율로 조질압연하는 것을 특징으로 하는 고강도 도금강판의 제조방법에 관한 것이다.In addition, the present invention is C: 0.06 ~ 0.08%, Mn: 0.55 ~ 0.65%, Si: 0.07-0.13%, P: 0.03% or less, S: 0.01% or less, N: 0.006% or less, acid value Al Steel slab composed of: 0.02 ~ 0.05%, Nb: 0.010 ~ 0.025%, remaining Fe and other unavoidable impurities is heated to 1150-1220 ℃, hot-rolled at 870-910 ℃, and temperature range of 540-620 ℃ After winding at 50 ° C, cold rolling is carried out at a reduction ratio of 50% or more to produce a cold rolled steel sheet, and after recrystallization annealing at a temperature range of 770 to 820 ° C, hot dip galvanizing or hot dip galvanizing, followed by 1.0 to 1.6%. It relates to a method for producing a high strength plated steel sheet, characterized in that the rough rolling at a reduction ratio of.
바람직하게는, 상기 고강도 도금강판의 제조방법에 있어서, 상기 냉연강판의 두께가 0.6∼1.2mm인 경우에는 열연권취온도: 580∼ 620℃, 재결정소둔온도: 780~820℃ 및 조질압연압하율: 1.2∼1.6%로 하고; 상기 냉연강판의 두께가 1.2∼1.8mm인 경우에는 열연권취온도: 560∼600℃, 재결정소둔온도: 780~820℃ 및 조질압연 압하율: 1.1∼1.5%로 하고; 그리고 상기 냉연강판의 두께가 1.8∼2.5mm인 경우에는 열연권취온도: 540∼ 580℃, 재결정소둔온도: 770~810℃ 및 조질압연 압하율: 1.0∼1.4%로 설정한다.Preferably, in the manufacturing method of the high strength plated steel sheet, when the cold rolled steel sheet has a thickness of 0.6 to 1.2 mm, hot rolling temperature: 580 to 620 ° C., recrystallization annealing temperature: 780 to 820 ° C., and temper rolling rolling rate: 1.2 to 1.6%; When the thickness of the cold rolled steel sheet is 1.2 to 1.8 mm, hot rolling temperature: 560 to 600 ° C., recrystallization annealing temperature: 780 to 820 ° C., and temper rolling rolling rate: 1.1 to 1.5%; When the thickness of the cold rolled steel sheet is 1.8 to 2.5 mm, hot rolling temperature: 540 to 580 ° C., recrystallization annealing temperature: 770 to 810 ° C., and temper rolling rolling rate: 1.0 to 1.4%.
이하 본 발명을 상세히 설명한다. Hereinafter, the present invention will be described in detail.
본 발명은 Ti 을 첨가하지 않고 Nb 첨가량을 낮추고 Mn 및 Si의 함량을 높여 석출강화와 고용강화를 동시에 확보함으로써 보다 경제적으로 높은 강도를 확보할 수 있을 뿐만 아니라 항복강도 편차를 저감시킬 수 있는 것이다.In the present invention, by lowering the amount of Nb added without adding Ti and increasing the content of Mn and Si to secure precipitation and solid solution at the same time, it is possible to secure higher strength more economically as well as to reduce variation in yield strength.
이하, 성분범위의 한정이유에 대하여 설명한다.Hereinafter, the reason for limitation of the component range is demonstrated.
상기 C는 석출물 형성 원소로 중요한 역할을 하며, 그 함량이 0.06% 미만의 경우 충분한 석출 효과를 얻을 수 없고, 0.08%를 초과하게 되면 제강 연주 공정에서 주 편 크랙 발생 가능성이 높아지고 특히 소둔 후 냉각시 베이나이트 조직이 형성되어 복합조직의 형태를 이루어 소망의 재질이 확보하기 어렵다. C plays an important role as a precipitate-forming element, and if the content is less than 0.06%, sufficient precipitation effect cannot be obtained. If the content exceeds 0.08%, cast cracks are more likely to occur in the steelmaking process, and especially after annealing and cooling. The bainite structure is formed to form a complex structure so that the desired material is difficult to secure.
따라서, C의 함량은 0.06~0.08%로 제한하는 것이 바람직하다.Therefore, the content of C is preferably limited to 0.06 to 0.08%.
상기 Mn은 강중 S를 MnS로 석출시켜 열간압연시 S에 의한 판파단 발생 및 고온취화를 억제시키는 중요한 역할을 할 뿐만 아니라 본 발명에서는 고용강화에 의한 강도향상을 가져오는 성분으로서, 그 함량이 0.55%미만의 경우에는 목적하는 강도 확보가 곤란하고 0.65%를 초과하게 되면 목적하는 강도는 확보되나 연신율이 급격한 감소를 가져오고, 소둔시 Mn산화물의 강판표면으로의 용출이 심하여 표면 청정도 및 내산화성에 미치는 영향이 크다. The Mn precipitates S in MnS and plays an important role of suppressing plate breakage and high temperature embrittlement caused by S during hot rolling, and in the present invention, Mn is a component that brings about strength improvement due to solid solution strengthening, and its content is 0.55. If it is less than%, it is difficult to secure the desired strength, and if it exceeds 0.65%, the desired strength is secured, but the elongation is drastically reduced, and the annealing of Mn oxide to the surface of the steel sheet during annealing causes severe surface cleanliness and oxidation resistance. The impact is great.
따라서, Mn의 함량은 0.55~0.65%로 제한하는 것이 바람직하다. Therefore, the content of Mn is preferably limited to 0.55 ~ 0.65%.
상기 Si은 탈산 및 고용강화에 의한 강도향상을 위하여 첨가하는 성분으로서, 그 함량이 0.07%미만인 경우에는 첨가효과를 얻을 수 없고, 또한 0.13%를 초과하는 경우에는 도금성을 열화시킬 우려가 있으므로, 그 함량은 0.07~0.13%로 제한하는 것이 바람직하다. Si is a component added to improve the strength by deoxidation and solid solution strengthening. When the content is less than 0.07%, the effect of addition is not obtained, and when the content exceeds 0.13%, the plating property may be deteriorated. The content is preferably limited to 0.07 to 0.13%.
상기 P는 본 발명강에서 성형성을 크게 해치지 않으면서 강도확보가 가장 유리한 원소인데, 강중 P의 함량이 많을수록 강도상승에는 매우 유리하지만, 과잉의 P첨가는 취성파괴 발생가능성을 높여 열간압연 도중 슬라브의 판파단의 발생가능성이 증가될 뿐 아니라, 소둔완료 후 결정입계로의 확산 및 편석이 용이해짐에 따라 성형시 2차가공 취성 발생에 대한 문제점이 커지므로 0.03%이하로 제한하는 것이 바람직하다. The P is the most advantageous element to secure the strength without significantly deteriorating the formability in the present invention steel, the higher the content of P in the steel is very advantageous for the increase in strength, but the addition of excess P increases the probability of brittle fracture, slabs during hot rolling In addition to increasing the likelihood of plate breakage, as it becomes easier to diffuse and segregate to the grain boundary after annealing is completed, it is preferable to limit it to 0.03% or less, because the problem of occurrence of secondary processing brittleness during molding increases.
상기 S과 N는 강중 불순물로서 불가피하게 첨가되는 원소들이므로 가능한 한 낮게 관리하는 것이 바람직하다. 하지만, 그 함량들을 적게 관리할수록 강의 정련 비용이 높아진다. 따라서, 조업조건이 가능한 범위인 S의 함량 0.01% 이하, N함량 0.006% 이하로 관리하는 것이 바람직하다.Since S and N are inevitably added elements as impurities in steel, it is preferable to manage them as low as possible. However, the less they manage, the higher the refining cost of the steel. Therefore, it is preferable to manage the S content of 0.01% or less and the N content of 0.006% or less.
상기 Al은 탈산을 위해서 첨가되는 원소로서, 그 함량이 0.02% 미만의 경우 첨가효과를 충분히 얻을 수 없고, 0.05%를 초과하는 경우에는 제강 연주 조업시 개재물 과다 형성으로 인한 강판 표면 불량 발생 가능성이 높을 뿐만 아니라 제조 원가 상승을 가져오므로, 그 함량은 0.02~0.05%로 제한하는 것이 바람직하다. Al is an element added for deoxidation. If the content is less than 0.02%, the effect of addition is not sufficiently obtained. If Al is more than 0.05%, it is highly likely that surface defects occur due to excessive inclusions during steelmaking operation. In addition, the production cost increases, so the content is preferably limited to 0.02 ~ 0.05%.
상기 Nb은 열간압연중 고용 C를 NbC로 석출시켜 소둔 재결정 중에 결정립 미세화 및 석출물에 의한 강의 강도를 향상시키는 성분으로서, 그 함량이 0.010% 미만의 경우 충분한 NbC석출물이 형성되지 못하여 강도 상승 및 항복비 증가 효과를 얻을 수 없고, 그 함량이 0.025%를 초과하게 되면 연주주편 크랙 발생이 높아지게 되므로, 그 함량은 0.010~0.025%로 제한하는 것이 바람직하다. The Nb is a component that enhances the strength of the steel due to grain refinement and precipitation during annealing recrystallization by precipitation of solid solution C during hot rolling, and when the content is less than 0.010%, sufficient NbC precipitates are not formed to increase strength and yield ratio. If the increase effect is not obtained and the content exceeds 0.025%, the occurrence of cracks in the cast slab increases, so the content is preferably limited to 0.010% to 0.025%.
이하, 제조조건에 대하여 설명한다.Hereinafter, manufacturing conditions are demonstrated.
본 발명의 냉연강판은 상기와 같이 조성되는 강 슬라브를 열간압연, 냉간압연, 재결정소둔을 통해 제조한다. 재결정소둔은 냉연강판을 연속소둔처리하여 냉연강판으로 제공할 수도 있고, 도금하여 도금강판 또는 도금후 합금화처리하여 합금화 도금강판으로 제공할 수 있다. The cold rolled steel sheet of the present invention is produced by hot rolling, cold rolling, recrystallization annealing the steel slab formed as described above. Recrystallization annealing may be provided as a cold-rolled steel sheet by continuous annealing the cold-rolled steel sheet, or may be provided as a plated steel sheet or an alloyed plated steel sheet by post-plating alloying.
먼저, 상기와 같이 조성되는 강 슬라브를 1150 ∼ 1220℃로 가열하여 870∼ 910℃에서 열간마무리압연하고, 540∼ 620℃의 온도 범위에서 권취를 행하여 열연강판을 제조한다.First, the steel slab formed as mentioned above is heated to 1150-1220 degreeC, hot-rolled at 870-910 degreeC, and it winds up in the temperature range of 540-620 degreeC, and manufactures a hot rolled steel sheet.
권취온도가 540℃미만에서는 고용 C를 완전히 석출하지 못하여 석출물 효과가 떨어질뿐만 아니라 권취시 판 형상 불량의 문제가 나타나며, 권취온도가 620℃를 초과하게 되면 석출물이 조대화 되는 경향을 가지므로 석출물 효과가 크지 않아 항복비가 낮아지는 경향이 있다. If the coiling temperature is less than 540 ℃, not only do not precipitate the solid solution C completely, the precipitate effect is reduced, but also the problem of poor plate shape during the winding, and when the coiling temperature exceeds 620 ℃ precipitate tends to coarse The yield ratio tends to be low because it is not large.
냉연강판 및 도금강판의 두께가 0.6∼1.2mm인 경우에는 열연권취온도는 580∼ 620℃로, 냉연강판 및 도금강판의 두께가 1.2∼1.8mm인 경우에는 열연권취온도는 560∼ 600℃로, 그리고 냉연강판 및 도금강판의 두께가 1.8∼2.5mm인 경우에는 열연권취온도는 540∼ 580℃로 설정하는 것이 바람직하며, 상기와 같이 제한하므로써, 항복강도 편차를 보다 저감시킬 수 있다.When the thickness of the cold rolled steel plate and the plated steel sheet is 0.6 to 1.2 mm, the hot rolled coiling temperature is 580 to 620 ° C. When the thickness of the cold rolled steel sheet and the plated steel sheet is 1.2 to 1.8 mm, the hot rolled coiling temperature is 560 to 600 ° C. When the thickness of the cold rolled steel sheet and the plated steel sheet is 1.8 to 2.5 mm, the hot rolled coiling temperature is preferably set to 540 to 580 ° C., and the yield strength variation can be further reduced by limiting as described above.
상기와 같이 제조된 열연강판은 필요에 따라 산세처리한 후, 냉간압연한다.The hot rolled steel sheet manufactured as described above is subjected to pickling as necessary, followed by cold rolling.
냉간압연은 압하율을 50% 이상으로 하는 것이 바람직하다.It is preferable that cold rolling sets a reduction ratio to 50% or more.
냉간압하율이 50% 미만인 경우에는 석출물 핵생성을 위한 임계 핵생성 사이트의 감소로 충분한 석출물이 형성되지 않는다. If the cold reduction rate is less than 50%, sufficient precipitates are not formed due to the reduction of critical nucleation sites for precipitate nucleation.
다음으로 냉연강판을 재결정소둔한다. 재결정소둔은 760~810℃에서 행하는 것이 바람직하다. 소둔온도가 760℃미만의 경우 이 소둔온도가 미재결정 영역으로 코일내 재질 편차가 매우 높아 강판을 실용화할 수 없으며, 810℃ 초과의 조건에서는 고온 소둔에 따른 석출물 조대화 경향으로 충분한 석출 효과가 나타나지 않는다. Next, re-anneal the cold rolled steel sheet. It is preferable to perform recrystallization annealing at 760-810 degreeC. If the annealing temperature is less than 760 ℃, the steel sheet cannot be put into practical use because the annealing temperature is unrecrystallized and the material variation in the coil is very high.In the condition above 810 ℃, the precipitation tendency is increased due to the coarsening tendency of the precipitate due to the high temperature annealing. Do not.
상기 냉연강판의 두께가 0.6∼1.2mm인 경우에는 재결정소둔온도는 770~810℃로, When the thickness of the cold rolled steel sheet is 0.6 ~ 1.2mm, the recrystallization annealing temperature is 770 ~ 810 ℃,
상기 냉연강판의 두께가 1.2∼1.8mm인 경우에는 재결정소둔온도는 770~810℃로 하 고, 그리고 두께가 1.8∼2.5mm인 냉연강판의 제조방법에서는 재결정소둔온도는 760~800℃로 설정하는 것이 바람직하며, 상기와 같이 제한하므로써, 항복강도 편차를 보다 저감시킬 수 있다.When the cold rolled steel sheet has a thickness of 1.2 to 1.8 mm, the recrystallization annealing temperature is set to 770 to 810 ° C., and the recrystallization annealing temperature is set to 760 to 800 ° C. in the manufacturing method of the cold rolled steel sheet having a thickness of 1.8 to 2.5 mm. It is preferable that the yield strength variation can be further reduced by limiting as described above.
재결정소둔처리한 강판은 필요에 따라 용융아연도금하거나 또는 용융아연도금후 합금화처리한다. The recrystallized annealing steel sheet may be hot dip galvanized or alloyed after hot dip galvanizing as necessary.
상기 용융아연도금이나 합금화용융아연도금은 통상적인 방법에 따라 행한다.The hot dip galvanizing and alloying hot dip galvanizing is performed according to a conventional method.
합금화처리를 하는 경우 상기 재결정소둔은 합금화 용융도금 연속로에서 행할 수 있다. In the case of the alloying treatment, the recrystallization annealing may be performed in an alloyed hot dip plating furnace.
재결정소둔을 합금화 용융도금 연속로에서 행하는 경우, 도금강판의 두께가 0.6∼1.2mm인 경우에는 재결정소둔온도는 780~820℃로 하고, 상기 도금강판의 두께가 1.2∼1.8mm인 경우에는 재결정소둔온도는 780~820℃로, 그리고 상기 냉연강판의 두께가 1.8∼2.5mm인 경우에는 재결정소둔온도는 770~810℃로 설정하는 것이 바람직하며, 상기와 같이 제한하므로써, 항복강도 편차를 보다 저감시킬 수 있다.When recrystallization annealing is performed in an alloyed hot dip plating furnace, when the thickness of the plated steel sheet is 0.6 to 1.2 mm, the recrystallization annealing temperature is 780 to 820 ° C., and when the thickness of the plated steel sheet is 1.2 to 1.8 mm, the recrystallization annealing is performed. If the temperature is 780 ~ 820 ℃, and the thickness of the cold rolled steel sheet is 1.8 ~ 2.5mm, the recrystallization annealing temperature is preferably set to 770 ~ 810 ℃, by limiting as described above, to further reduce the yield strength variation Can be.
상기 냉연강판 및 도금강판은 1.0∼1.6%의 압하율로 조질압연한다.The cold rolled steel sheet and the plated steel sheet are temper rolled at a rolling ratio of 1.0 to 1.6%.
두께가 0.6∼2.5mm인 냉연강판을 제조하는 경우에는 조질압연압하율은 1.2∼1.6%로 설정하는 것이 바람직하다.In the case of producing a cold rolled steel sheet having a thickness of 0.6 to 2.5 mm, the tempered rolling reduction ratio is preferably set to 1.2 to 1.6%.
또한, 두께가 0.6∼1.2mm인 도금강판을 제조하는 경우에는 조질압연압하율은 1.2∼1.6%로, 두께가 1.2∼1.8mm인 도금강판을 제조하는 경우에는 조질압연 압하율은 1.1∼1.5%로, 그리고 두께가 1.8∼2.5mm인 도금강판을 제조하는 경우에는 조질압연 압하율은 1.0∼1.4%로 설정하는 것이 바람직하며, 상기와 같이 제한하므로써, 항복 강도 편차를 보다 저감시킬 수 있다.In the case of producing a plated steel sheet having a thickness of 0.6 to 1.2 mm, the tempered rolling reduction rate is 1.2 to 1.6%, and when the plated steel sheet having a thickness of 1.2 to 1.8 mm is produced, the tempered rolling rate is 1.1 to 1.5%. In the case of producing a plated steel sheet having a thickness of 1.8 to 2.5 mm, the temper rolling rolling reduction ratio is preferably set to 1.0 to 1.4%, and the yield strength variation can be further reduced by limiting as described above.
이하, 실시예를 통하여 본 발명을 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.
[실시예]EXAMPLE
하기 표 1과 같이 조성되는 강 슬라브를 하기 표 2와 같은 조건으로 열간압연, 냉간압연, 용융아연도금 및 조질압연을 행하고, 기계적 특성을 측정하고, 그 결과를 하기 표 3에 나타내었다.The steel slab formed as shown in Table 1 was subjected to hot rolling, cold rolling, hot dip galvanizing and temper rolling under the conditions as shown in Table 2 below, and the mechanical properties were measured, and the results are shown in Table 3 below.
표 2의 조건 이외의 공정은 통상적인 방법에 따라 행하였다.Processes other than the conditions of Table 2 were performed in accordance with a conventional method.
하기 표 3의 기계적 특성값은 인장시험시편이 압연방향과 90도인 시편에 대한 값이다.The mechanical properties shown in Table 3 below are for the specimens in which the tensile test specimen is 90 degrees to the rolling direction.
상기 표 3에 나타난 바와 같이, 본 발명에 부합되는 발명재 1 및 2는 항복강도가 높을 뿐만 아니라 항복강도 편차도 적음을 알 수 있다.As shown in Table 3, Inventive Materials 1 and 2 according to the present invention can be seen that not only the yield strength is high but also the yield strength variation is small.
상술한 바와 같이, 본 발명에 따르면 Ti를 첨가하지 않고 Nb의 함량도 낯춤으로써 제조원가를 절감할 수 있을 뿐만 아니라 재결정온도를 낮추어 항복강도 편차를 적게 함으로써 산업상, 경제적으로 활용가치가 높은 강판을 제공할 수 있다.As described above, according to the present invention, it is possible to reduce manufacturing cost by reducing the content of Nb without adding Ti, but also to reduce the yield strength variation by lowering the recrystallization temperature, thereby providing an industrially and economically useful steel sheet. can do.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100928784B1 (en) | 2007-12-27 | 2009-11-25 | 주식회사 포스코 | High yield ratio high strength cold rolled steel sheet, galvanized steel sheet and manufacturing method thereof |
| KR100957969B1 (en) | 2007-12-27 | 2010-05-17 | 주식회사 포스코 | High Strength High and High Yield Ratio Cold Rolled Steel Sheet and Galvanized Steel Sheet having Excellent Weldability and Manufacturing Method Thereof |
| CN103146998A (en) * | 2013-02-28 | 2013-06-12 | 首钢总公司 | Over-400Mpa galvanized high-strength structural steel and production method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100595946B1 (en) | 2000-02-29 | 2006-07-03 | 제이에프이 스틸 가부시키가이샤 | High tensile cold-rolled steel sheet having excellent strain aging hardening properties |
| KR20060096002A (en) * | 2003-09-30 | 2006-09-05 | 신닛뽄세이테쯔 카부시키카이샤 | High-yield-ratio high-strength thin steel sheet and high-yield-ratio high-strength hot-dip galvanized thin steel sheet excelling in weldability and ductility as well as high-yield-ratio high-strength alloyed hot-dip galvanized thin steel sheet and process for producing the same |
| JP2006265607A (en) | 2005-03-23 | 2006-10-05 | Nippon Steel Corp | High strength cold rolled steel sheet, high strength hot dip galvanized steel sheet, high strength alloyed hot dip galvannealed steel sheet, production method of high strength cold rolled steel sheet, production method of high hot dip galvannealed steel sheet, and production method of high strength alloyed galvannealed steel sheet |
| JP2006283156A (en) | 2005-04-01 | 2006-10-19 | Nippon Steel Corp | High-strength cold rolled steel sheet having excellent formability and weldability, high-strength hot dip galvanized steel sheet, high-strength alloyed galvannealed steel sheet, production method of high-strength cold rolled steel sheet, production method of high-strength hot dip galvanized steel sheet, and production method of high-strength alloyed galvannealed steel sheet |
-
2006
- 2006-12-19 KR KR1020060130481A patent/KR100782760B1/en active IP Right Grant
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100595946B1 (en) | 2000-02-29 | 2006-07-03 | 제이에프이 스틸 가부시키가이샤 | High tensile cold-rolled steel sheet having excellent strain aging hardening properties |
| KR20060096002A (en) * | 2003-09-30 | 2006-09-05 | 신닛뽄세이테쯔 카부시키카이샤 | High-yield-ratio high-strength thin steel sheet and high-yield-ratio high-strength hot-dip galvanized thin steel sheet excelling in weldability and ductility as well as high-yield-ratio high-strength alloyed hot-dip galvanized thin steel sheet and process for producing the same |
| JP2006265607A (en) | 2005-03-23 | 2006-10-05 | Nippon Steel Corp | High strength cold rolled steel sheet, high strength hot dip galvanized steel sheet, high strength alloyed hot dip galvannealed steel sheet, production method of high strength cold rolled steel sheet, production method of high hot dip galvannealed steel sheet, and production method of high strength alloyed galvannealed steel sheet |
| JP2006283156A (en) | 2005-04-01 | 2006-10-19 | Nippon Steel Corp | High-strength cold rolled steel sheet having excellent formability and weldability, high-strength hot dip galvanized steel sheet, high-strength alloyed galvannealed steel sheet, production method of high-strength cold rolled steel sheet, production method of high-strength hot dip galvanized steel sheet, and production method of high-strength alloyed galvannealed steel sheet |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100928784B1 (en) | 2007-12-27 | 2009-11-25 | 주식회사 포스코 | High yield ratio high strength cold rolled steel sheet, galvanized steel sheet and manufacturing method thereof |
| KR100957969B1 (en) | 2007-12-27 | 2010-05-17 | 주식회사 포스코 | High Strength High and High Yield Ratio Cold Rolled Steel Sheet and Galvanized Steel Sheet having Excellent Weldability and Manufacturing Method Thereof |
| CN103146998A (en) * | 2013-02-28 | 2013-06-12 | 首钢总公司 | Over-400Mpa galvanized high-strength structural steel and production method thereof |
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