KR100431802B1 - Method for Manufacturing Hot Rolled Steel Sheet with Good Formability - Google Patents

Method for Manufacturing Hot Rolled Steel Sheet with Good Formability Download PDF

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KR100431802B1
KR100431802B1 KR10-1999-0057853A KR19990057853A KR100431802B1 KR 100431802 B1 KR100431802 B1 KR 100431802B1 KR 19990057853 A KR19990057853 A KR 19990057853A KR 100431802 B1 KR100431802 B1 KR 100431802B1
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hot rolled
temperature
steel sheet
elongation
steel
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KR10-1999-0057853A
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KR20010056181A (en
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김진철
박기종
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주식회사 포스코
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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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/663—Bell-type furnaces
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

본 발명은 저탄소강을 이용하여 성형성이 요구되는 열연박판을 제조하는 방법에 관한 것으로, 열연박판의 제조방법에 있어서, 중량비로, 0.02∼0.03％의 C, 0.10∼0.20％의 Mn, 0.015% 이하의 P, 0.010% 이하의 S, 0.02∼0.04％의 가용성 Al, 40ppm 이하의 N 및 잔부 Fe로 조성되는 슬라브를 Ar3 변태점 이상의 온도로 유지하여 1.2∼2.3㎜두께로 사상압연한 후, 600℃ 이하의 온도에서 권취하여 열연코일로 형성한 다음, 645∼655℃의 온도범위에서 2∼5시간 동안 상소둔하므로써, 연신율이 향상되어 가공성이 우수한 재질의 열연강판을 생산할 수 있게 한 것이다.The present invention relates to a method for producing a hot rolled thin sheet requiring formability using low carbon steel. In the method for producing a hot rolled thin sheet, the weight ratio is 0.02 to 0.03% C, 0.10 to 0.20% Mn, 0.015% The slab composed of the following P, 0.010% or less S, 0.02 to 0.04% soluble Al, 40 ppm or less N, and the balance Fe was maintained at a temperature above the Ar3 transformation point, followed by finishing rolling at a thickness of 1.2 to 2.3 mm, followed by 600 ° C. It is wound at the following temperature and formed into a hot rolled coil, and then annealing for 2 to 5 hours in the temperature range of 645 ~ 655 ℃, the elongation is improved to be able to produce a hot rolled steel sheet of excellent workability.

Description

가공성이 우수한 열연박판 제조방법 {Method for Manufacturing Hot Rolled Steel Sheet with Good Formability}Process for manufacturing hot rolled sheet with excellent processability {Method for Manufacturing Hot Rolled Steel Sheet with Good Formability}

본 발명은 저탄소강을 이용하여 성형성이 우수한 열연박판을 제조하는 방법에 관한 것으로, 특히 열연박판의 성분을 조절한 다음 사상압연온도와 소둔처리온도를 적절하게 조절하여 연신율을 증대시킬 수 있도록 된 가공성이 우수한 열연박판의 제조방법에 관한 것이다.The present invention relates to a method for manufacturing a hot rolled sheet having excellent formability using low carbon steel, and in particular, to adjust the components of the hot rolled sheet and then to adjust the finishing rolling temperature and annealing temperature appropriately to increase the elongation. It is related with the manufacturing method of the hot rolled sheet excellent in workability.

일반적으로, 열간압연 연질강판을 성형성이 우수한 박판으로 제조하는 과정에서 성형성(이하, 연성 또는 연신율이라 표현함)을 좌우하게 되는 주요인자로, 강중에 첨가되는 주요성분이나 열간압연과정에서의 압연출측온도 및 권취시의 온도 등으로 알려져 있다.In general, the main factor that affects the formability (hereinafter, referred to as ductility or elongation) in the process of manufacturing a hot rolled soft steel sheet with excellent formability, is a major component added to steel or hot rolling process It is known as the production side temperature and the temperature at the time of winding.

그리고, 연성이 우수한 열연강판 중에서, 탄소가 0.02∼ 0.04％ 포함되면서 망간이 0.25％ 포함된 저탄소강은, Ar3변태점 이상의 온도에서 열간압연을 마무리한 후, 550∼650℃의 온도에서 권취하며, 극저탄소강은 티타늄이나 니오븀을 첨가하여 심가공용 열연강판으로 제조하게 된다.Among the hot rolled steel sheets having excellent ductility, low carbon steels containing 0.02% to 0.04% carbon and 0.25% manganese are wound at a temperature of 550 to 650 ° C after finishing hot rolling at a temperature above the Ar3 transformation point. Low carbon steel is made of hot rolled steel sheet for deep processing by adding titanium or niobium.

먼저, 연성이 우수한 열연강판을 제조하는 공지의 기술로는, 탄소가 0.002중량％ 첨가되면서 티타늄이 0.03중량％ 첨가된 강을, Ar3변태점 이상의 온도에서 마무리 압연을 행한 후 600℃이하의 온도에서 권취함으로써, 인장강도가 28∼29㎏/㎟정도이고, 연신율이 55％정도인 심가공용 열연강판을 얻은 경우가 보고되었다.First, as a well-known technique for manufacturing a hot rolled steel sheet having excellent ductility, steel with 0.03% by weight of titanium added while 0.002% by weight of carbon is subjected to finish rolling at a temperature above Ar3 transformation point and then wound at a temperature of 600 ° C or lower. As a result, a case has been reported in which a hot-rolled steel sheet for deep processing having a tensile strength of about 28 to 29 kg / mm 2 and an elongation of about 55% is obtained.

또한, 탄소가 0.002중량％ 정도 함유되면서 티타늄이나 니오븀을 0.01∼0.02중량％ 정도 첨가된 강을, 650℃이상의 온도에서 권취하여, 연신율이 50∼55％정도인 심가공용 열연강판을 얻은 경우가 보고되었다.In addition, steel containing about 0.002% by weight of carbon and 0.01 to 0.02% by weight of titanium or niobium was wound up at a temperature of 650 ° C or higher to obtain a hot-rolled steel sheet for deep processing having an elongation of about 50 to 55%. It became.

그러나, 열연강판의 연성을 확보함에 있어, 극저탄소에 티타늄이나 니오븀을 첨가하는 것은 연신율을 향상시키는 데에는 효율이 있으나, 모두 강판의 두께가 3.0㎜ 이상으로서 얇은 박판의 경우에는 그 제조대상에서 제외되었다.However, in securing the ductility of the hot rolled steel sheet, adding titanium or niobium to ultra low carbon is effective in improving the elongation, but all of them are excluded from the manufacture of thin sheets having a thickness of 3.0 mm or more. .

또한, 탄소가 0.04중량％ 정도로 함유되면서 망간이 0.15중량％ 또는 0.03∼0.20중량％정도로 함유된 저탄소강에 구리성분을 첨가하여, 두께가 1.6㎜ 정도이면서 연신율이 41％정도인 강판을 얻은 경우도 보고되었다.In addition, when a copper component is added to a low carbon steel containing about 0.04% by weight of carbon and about 0.15% by weight of manganese or about 0.03 to 0.20% by weight, a steel sheet having an elongation of about 1.6 mm and an elongation of about 41% is obtained. Reported.

상기와 같이, 열간압연 연강판을 제조함에 있어 두께가 얇아지면서 발생되는 문제점은, 열간압연소재가 얇아짐에 따라 압연을 행하는 동안 강판의 방열량이 증가하기 때문에, 압연 마무리 단계에서 강판의 온도가 Ar3변태점 이하로 저하될 가능성이 높아지게 된다는 것이다.As described above, the problem that occurs when the thickness is thin in manufacturing the hot rolled mild steel sheet, the heat dissipation amount of the steel sheet during the rolling is increased as the hot rolled material becomes thin, the temperature of the steel sheet in the rolling finish step is Ar3 The possibility of falling below the transformation point is increased.

즉, Ar3변태점 이하의 온도에서는, 내부조직에 조대페라이트 결정립과 미세 페라이트 결정립이 혼재된 혼합조직 또는 연신페라이트 결정립과 미세페라이트 결정립이 잔존하는 변형 조직으로 나타나게 되어, 연신율이 급격하게 저하된다.That is, at the temperature below the Ar3 transformation point, the internal structure appears as a mixed structure in which coarse ferrite grains and fine ferrite grains are mixed, or a deformed structure in which stretched ferrite grains and fine ferrite grains remain, and the elongation is drastically lowered.

특히, 압연되는 열연강판의 폭방향 양단부에서는 이들 혼합조직과 변형조직의 발생가능성이 높아지는데, 이러한 점을 고려하여 압연강판의 양단부를 제거한다고 가정할 경우, 그 제거량이 증가되므로써 강판의 실수율이 상대적으로 저하되는 문제점이 있다.Particularly, the probability of occurrence of these mixed and deformed structures increases at both ends of the rolled hot rolled steel sheet in the width direction. In consideration of this, it is assumed that both ends of the rolled steel sheet are removed. There is a problem that is lowered.

한편, 혼합조직에 의한 재질연화를 방지함과 더불어 연성을 향상시키기 위해, Ar3변태점의 온도저하에 유효한 성분으로 알려진 크롬(Cr)이나 보론(B)을 첨가하여 열연강판을 제조하는 사례가 보고되었다.On the other hand, in order to prevent softening of the material by the mixed structure and to improve ductility, a case has been reported in which a hot rolled steel sheet is manufactured by adding chromium (Cr) or boron (B), which are known as effective ingredients at the temperature drop of Ar3 transformation point. .

즉, 탄소가 0.04중량％로 함유되면서 망간이 0.1중량％로 함유된 성분을 기본성분으로하여 크롬을 0.50중량％, 보론을 0.001중량％로 첨가하여 1.2∼2.3㎜의 열연강판을 제조한 결과, 인장강도가 33㎏/㎟정도이고, 연신율이 48％정도인 심가공용 열연강판을 얻은 경우가 보고되었다.That is, as a result of preparing a hot rolled steel sheet of 1.2 to 2.3 mm by adding 0.50% by weight of chromium and 0.001% by weight of boron, based on a component containing 0.04% by weight of carbon and 0.1% by weight of manganese, It has been reported that a hot rolled steel sheet for deep processing has a tensile strength of about 33 kg / mm 2 and an elongation of about 48%.

또한, 대한민국 특허출원(제96-55358호)에서도 저탄소화 및 저망간화에 의한 기지의 연질화, 크롬첨가에 의한 Ar3변태점의 온도저하의 방지 및 열간압연 마무리 압연직전에 양단부를 에지히터로 순간적으로 가열하여 온도저하를 방지함으로써, 인장강도가 33㎏/㎟ 정도이고, 연신율이 48％ 정도인 심가공용 열연강판을 얻은 경우가 제안되었다.In addition, Korean patent application (No. 96-55358) also prevents temperature reduction of Ar3 transformation point due to low carbonization and low manganeseization, prevents the temperature drop of Ar3 transformation point due to chromium addition, and instantaneously the edge heaters at both ends immediately before hot rolling finish rolling. It has been proposed to obtain a hot-rolled steel sheet for deep processing, which has a tensile strength of about 33 kg / mm 2 and an elongation of about 48% by preventing the temperature decrease by heating to a temperature.

그러나, 상기 방법은 열연강판의 재질연질화를 방지함과 더불어 연성을 향상시키는 과정에서, 크롬(Cr)이나 보론(B) 등의 성분을 별도로 첨가함으로써 Ar3변태점의 온도가 저하되는 것을 방지하는 데는 효과가 있었지만, 연신율의 향상에는 그다지 도움이 되지 않았다.However, in the above method, in order to prevent soft nitriding of the hot rolled steel sheet and to improve ductility, it is possible to prevent the temperature of the Ar 3 transformation point from being lowered by adding components such as chromium (Cr) and boron (B) separately. Although it worked, it did not help much in improving the elongation.

이에, 본 발명은 상기한 바와 같은 문제점들을 해결하기 위하여 안출된 것으로, 열연박판의 성분을 조절한 다음, 사상압연온도와 소둔처리온도를 적절하게 조절하여 낮은 권취온도에서도 연신율을 증대시킬 수 있도록 된 가공성이 우수한 열연박판 제조 방법을 제공하는 데에 그 목적이 있다.Thus, the present invention was devised to solve the above problems, and after adjusting the components of the hot rolled sheet, it is possible to increase the elongation even at a low winding temperature by appropriately adjusting the finishing rolling temperature and annealing treatment temperature. The purpose is to provide a hot rolled sheet manufacturing method excellent in workability.

이하, 본 발명에 따른 실시예들을 첨부된 표들을 참고로하여 상세하게 설명하면 다음과 같다.Hereinafter, the embodiments according to the present invention will be described in detail with reference to the accompanying tables.

본 발명은, 열연박판의 제조방법에 있어서, 중량비로, 0.02∼0.03％의 C, 0.10∼0.20％의 Mn, 0.015% 이하의 P, 0.010% 이하의 S, 0.02∼0.04％의 가용성 Al, 40ppm 이하의 N 및 잔부 Fe로 조성되는 슬라브를 Ar3 변태점 이상의 온도로 유지하여 1.2∼2.3㎜두께로 사상압연한 후, 600℃ 이하의 온도에서 권취하여 열연코일로 형성한 다음, 645∼655℃의 온도범위에서 2∼5시간 동안 상소둔하는 것을 특징으로 한다.In the manufacturing method of a hot rolled sheet, this invention WHEREIN: 0.02 to 0.03% C, 0.10 to 0.20% Mn, 0.015% or less P, 0.010% or less S, 0.02 to 0.04% soluble Al, 40 ppm The slab composed of the following N and the balance Fe is kept at a temperature not lower than the Ar3 transformation point, and subjected to filament rolling to a thickness of 1.2 to 2.3 mm, wound up at a temperature of 600 ° C. or lower, and formed into a hot rolled coil, followed by a temperature of 645 to 655 ° C. It is characterized by annealing for 2 to 5 hours in the range.

상기 열연박판 중의 탄소는, 심가공용 열간압연 박판을 제조함에 있어 적정 강도 및 연성을 얻음과 동시에, Ar3변태점의 온도범위를 위해 함량이 제한된 것으로, 0.03％ 이상으로 함유되면 강도범위는 초과되고 연신율이 저하되며, 0.02％ 이하로 함유되면 Ar3변태점 온도가 저하되어 조직 내에 혼립조직이 발생된다.The carbon in the hot rolled thin sheet is obtained to obtain the appropriate strength and ductility in manufacturing the hot rolled thin sheet for deep processing, and the content is limited for the temperature range of the Ar 3 transformation point. When the content is lower than 0.02%, the Ar3 transformation point temperature is lowered, and a mixed structure is generated in the tissue.

그리고, 망간은, 고용강화원소로서 탄소와 더불어 강도를 확보하는 데 유효한 특징이 있을 뿐만 아니라 Ar3변태점의 온도범위를 유지하여 혼립조직의 발생을 방지시키지만, 역시 기지의 연질화를 위하여 0.10∼0.20％로 제한하였다.In addition, manganese is not only effective in securing strength with carbon as a solid solution strengthening element, but also maintains the temperature range of the Ar3 transformation point to prevent the formation of mixed structure, but also 0.10 to 0.20% for softening of the matrix. Limited to.

그리고, 인과 황은, 강 중의 불순물로서 불가피하게 존재하지만 통상의 규제치를 초과하면 연성과 인성에 악영향을 미치기 때문에, 각각 0.015％와 0.010％ 이하로 제한하였다.Phosphorus and sulfur are inevitably present as impurities in the steel, but if they exceed the usual regulation values, they adversely affect the ductility and toughness, so they are limited to 0.015% and 0.010% or less, respectively.

그리고, 알루미늄은, 강의 탈산에 필요한 원소로서, 통상의 경우 가용성(Soluble) 알루미늄이 0.04％ 이하로 되면, 충분히 탈산되기 때문에, 그 함량을 0.02∼0.04％로 제한하였다.In addition, aluminum is an element necessary for deoxidation of steel, and in general, when soluble aluminum becomes 0.04% or less, it is sufficiently deoxidized, so the content is limited to 0.02 to 0.04%.

그리고, 질소는, 강중에 고용되어 있으면서 탄소와 함께 연성을 저하시키게 되므로 40ppm이하로 제한하였고, 이들도 열간압연 후 600℃ 이하의 낮은 온도에서 권취함으로써 대부분의 강중에 고용됨을 알 수 있었다.In addition, nitrogen was limited to 40 ppm or less because it was reduced in ductility with carbon while being dissolved in steel, and it was found that these were also dissolved in most steel by winding at a low temperature of 600 ° C. or lower after hot rolling.

한편, 이러한 조성을 갖는 열연강판을 600℃를 초과하여 권취하면, AlN석출물이 미리 생성된다. 이때 생성된 AlN은 이후의 소둔공정에서 너무 성장되어 박판의 연신율 향상에 기여하지 못한다.상소둔로(Batch Annealing Furnace)에서 열처리하는 조건은 645∼655℃ 온도에서 2∼5시간이다. 이러한 온도범위는 열간압연 후 권취시 석출되지 못한 AlN 석출물을 조장시켜 연성을 향상시키기 위한 것이다. 즉, AlN이 석출됨으로써 금속기지 내에 있는 침입형 원소의 양을 감소시켜 슬립이 조장되면서 연성이 향상된다.On the other hand, when the hot rolled steel sheet having such a composition is wound over 600 ° C, AlN precipitates are generated in advance. At this time, the produced AlN is so grown in the subsequent annealing process that does not contribute to the improvement of the elongation of the thin plate. Heat treatment conditions in a batch annealing furnace (Batch Annealing Furnace) is 2 to 5 hours at a temperature of 645 ~ 655 ℃. This temperature range is intended to enhance ductility by promoting AlN precipitates that did not precipitate during winding after hot rolling. In other words, AlN precipitates to reduce the amount of invading elements in the metal base, thereby improving slippage and improving ductility.

여기서, 645℃ 미만의 온도에서는 AlN 석출이 일부만 일어나게 되어 연신율이 향상되지 못하는 특징이 있으며, 655℃ 이상의 온도에서 5시간 이상 소둔하게 되면 연신율이 50％대 이상으로 향상되는 반면에 전력의 소모량가 증대되어 경제적인 측면에서 단점이 있다.Here, the AlN precipitation occurs only a portion of the temperature below 645 ℃, the elongation is not improved, and when the annealing for more than 5 hours at a temperature of 655 ℃ or more, the elongation is improved to 50% or more while the power consumption is increased There are disadvantages in economic terms.

물론, 700℃ 이상의 온도에서는 비정상적인 조대한 결정립이 생성되어 항복강도 및 인장강도가 급격하게 저하될 뿐만 아니라 고온으로 인하여 소둔시 불음형상(Sticking)이 일어나게 되는 단점이 있다.Of course, the abnormal coarse grains are generated at a temperature of 700 ° C. or more, which leads to a sharp drop in yield strength and tensile strength, as well as a disadvantage in that frosting occurs during annealing due to high temperature.

[실시예]EXAMPLE

본 발명에 이용된 발명강(A) 및 비교강(B)은 표 1에서와 같은 성분으로 실험하였다. 표 1에서 비교강(B)은 크롬을 첨가한 강으로서 Ar3변태점 온도를 감소시켜 압연강판의 양단부 혼립을 저감시키면서 연신율을 향상시키는 것으로써, 최종 열연상태의 기계적 특성치를 본 발명강과 비교하기 위한 것으로 예시되었다.Inventive steel (A) and comparative steel (B) used in the present invention were tested with the same components as in Table 1. Comparative steel (B) in Table 1 is a chromium-added steel to reduce the Ar3 transformation point temperature to improve the elongation while reducing the mixing of both ends of the rolled steel sheet to compare the mechanical properties of the final hot rolled state with the present invention steel Illustrated.

강 종River bell 화학 성분(wt％)Chemical composition (wt%) 비 고Remarks CC SiSi MnMn PP SS S-AlS-Al CrCr TiTi NN AA 0.0230.023 0.050.05 0.140.14 0.0120.012 0.0080.008 0.0360.036 -- -- 2424 발명강Invention steel BB 0.0220.022 0.040.04 0.080.08 0.0120.012 0.0060.006 0.0270.027 0.200.20 -- 2121 비교강Comparative steel

표 1과 같은 성분을 갖는 강판을 1200℃에서 3시간 재가열한 후 열간압연을 행하여 두께 1.2㎜의 열연강판으로 제조하였으며, 이때 열간압연 마무리 목표온도는 880℃로 하였고, 600℃에서 권취를 행하였다.The steel sheet having the components shown in Table 1 was reheated at 1200 ° C. for 3 hours, and then hot rolled to produce a hot rolled steel sheet having a thickness of 1.2 mm. At this time, the hot rolling finish temperature was set at 880 ° C. and wound at 600 ° C. .

이 과정을 통해, 제조된 열연박판의 기계적 성질은 JIS 5호 인장시편을 이용하여 10㎜/min의 인장속도로 인장하여 평가하였으며, 이 때의 기계적 성질을 표 2에 도시하였다.Through this process, the mechanical properties of the prepared hot rolled sheet was evaluated by pulling at a tensile speed of 10 mm / min using a JIS No. 5 tensile test specimen, the mechanical properties at this time are shown in Table 2.

강 종River bell 권취온도(℃)Winding temperature (℃) 소둔 조건(℃,시간)Annealing condition (℃, time) 기계적 성질Mechanical properties 연신율Elongation 비 고Remarks 항복강도(Kg/㎟)Yield strength (Kg / ㎡) 인장강도(Kg/㎟)Tensile Strength (Kg / ㎡) 연신율(％)Elongation (%) 발명강AInventive Steel A 600600 550, 5550, 5 2626 3737 4343 미달Under 비교재1Comparative Material 1 600, 5600, 5 2525 3636 4444 미달Under 비교재2Comparative Material 2 650, 2650, 2 2424 3333 5252 합격pass 발명재1Invention 1 650, 5650, 5 2525 3535 5151 합격pass 발명재2Invention 2 700, 8700, 8 1717 2525 3939 미달Under 비교재3Comparative Material 3 비교강BComparative Steel B 600600 열연상태Hot rolled state 2323 3232 4646 합격pass 비교재4Comparative Material 4

표 2를 살펴보면, 발명강(A)를 이용한 발명재(1, 2)의 경우 소둔온도가 645∼655℃로 유지될 때 50％ 이상으로 인장되었으며, 비교강(B)를 이용한 비교재(4)의 경우에는 연신율이 46％ 내외로 인장되었음을 알 수 있었다.Referring to Table 2, in the case of the invention materials (1, 2) using the invention steel (A), when the annealing temperature is maintained at 645 ~ 655 ℃ was stretched to 50% or more, the comparative material using the comparative steel (B) (4 ), It was found that the elongation was about 46%.

따라서, 중량비로, 0.02∼0.03％C - 0.10∼0.20％Mn - 0.02∼0.04％Al이 첨가됨과 더불어 P, S, Si, N이 불순물로 첨가된 강판을, 1.2∼2.3㎜의 두께로 열간압연하는 과정에서 사상압연온도를 Ar3변태점 이상으로 유지한 다음 600℃ 이하의 온도에서 권취하여 열연코일로 형성시키고, 그리고, 소둔로에서 645∼655℃의 온도범위로 2∼5시간 동안 소둔처리하므로써, 항복강도가 22∼25Kg/㎟, 인장강도가 32∼35Kg/㎟, 연신율이 50％ 이상의 재질특성을 갖는 열연박판이 제조됨을 알 수 있다.Therefore, in the weight ratio, 0.02 to 0.03% C-0.10 to 0.20% Mn-0.02 to 0.04% Al was added and P, S, Si and N were hot rolled to a thickness of 1.2 to 2.3 mm to which the impurities were added. By maintaining the filament rolling temperature above the Ar3 transformation point in the process, and wound up at a temperature below 600 ℃ to form a hot rolled coil, and annealing for 2 to 5 hours in the temperature range of 645 ~ 655 ℃, It can be seen that a hot rolled sheet having a material property of yield strength of 22 to 25 Kg / mm 2, tensile strength of 32 to 35 Kg / mm 2, and elongation of 50% or more is manufactured.

이상에서 설명한 바와 같이, 본 발명에 따른 가공성이 우수한 열연박판 제조 방법에 의하면, 저탄소강의 성분을 조절한 다음 사상압연온도와 소둔처리온도를 적절하게 조절하므로써, 연신율이 향상되어 가공성이 우수한 재질의 열연강판을 생산할 수 있는 효과가 있는 것이다.As described above, according to the method for manufacturing a hot rolled sheet excellent in workability according to the present invention, by controlling the components of low carbon steel and then appropriately adjusting the finishing rolling temperature and the annealing treatment temperature, the elongation is improved to make the hot rolled material excellent in workability. The effect is to produce a steel sheet.

Claims (1)

열연박판의 제조방법에 있어서,In the method for producing a hot rolled sheet, 중량비로, 0.02∼0.03％의 C, 0.10∼0.20％의 Mn,0.015% 이하의 P, 0.010% 이하의 S, 0.02∼0.04％의 가용성 Al, 40ppm 이하의 N 및 잔부 Fe로 조성되는 슬라브를 Ar3 변태점 이상의 온도로 유지하여1.2∼2.3㎜두께로사상압연한 후, 600℃ 이하의 온도에서 권취하여 열연코일로 형성한 다음, 645∼655℃의 온도범위에서 2∼5시간동안 상소둔하는것을 특징으로 하는 가공성이 우수한 열연박판제조방법.The slab composed of 0.02 to 0.03% of C , 0.10 to 0.20% of Mn , 0.015% or less of P, 0.010% or less of S, 0.02 to 0.04% of soluble Al, 40 ppm or less of N, and the balance of Fe is selected from Ar3. by keeping it at a temperature above the transformation point and then rolled to a spirit 1.2~2.3㎜ thickness, by winding at a temperature not higher than 600 ℃ formed of a hot-rolled coil following, characterized in that it placed appeal for 2-5 hours at a temperature range of 645~655 ℃ Process for producing hot rolled sheet with excellent workability.
KR10-1999-0057853A 1999-12-15 1999-12-15 Method for Manufacturing Hot Rolled Steel Sheet with Good Formability KR100431802B1 (en)

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WO2014065623A1 (en) * 2012-10-26 2014-05-01 Sac Co., Ltd. Batch type annealing thermal processing facility and method of manufacturing steel plate by using the facility

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JPH0499124A (en) * 1990-08-02 1992-03-31 Kobe Steel Ltd Production of hot rolled mild steel sheet
KR960014368A (en) * 1994-10-27 1996-05-22 김만제 Manufacturing method of high ductility hot rolled mild steel sheet
KR19990053144A (en) * 1997-12-23 1999-07-15 이구택 Manufacturing method of hot rolled mild steel sheet for processing with excellent texture uniformity
KR100285649B1 (en) * 1996-11-19 2001-05-02 이구택 Method of manufacturing thin hot coil for deep drawing

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JPH0499124A (en) * 1990-08-02 1992-03-31 Kobe Steel Ltd Production of hot rolled mild steel sheet
KR960014368A (en) * 1994-10-27 1996-05-22 김만제 Manufacturing method of high ductility hot rolled mild steel sheet
KR100285649B1 (en) * 1996-11-19 2001-05-02 이구택 Method of manufacturing thin hot coil for deep drawing
KR19990053144A (en) * 1997-12-23 1999-07-15 이구택 Manufacturing method of hot rolled mild steel sheet for processing with excellent texture uniformity
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014065623A1 (en) * 2012-10-26 2014-05-01 Sac Co., Ltd. Batch type annealing thermal processing facility and method of manufacturing steel plate by using the facility

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