KR100545086B1 - Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability - Google Patents

Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability Download PDF

Info

Publication number
KR100545086B1
KR100545086B1 KR1020010081210A KR20010081210A KR100545086B1 KR 100545086 B1 KR100545086 B1 KR 100545086B1 KR 1020010081210 A KR1020010081210 A KR 1020010081210A KR 20010081210 A KR20010081210 A KR 20010081210A KR 100545086 B1 KR100545086 B1 KR 100545086B1
Authority
KR
South Korea
Prior art keywords
less
steel sheet
low carbon
cold rolled
hot
Prior art date
Application number
KR1020010081210A
Other languages
Korean (ko)
Other versions
KR20030050704A (en
Inventor
이규영
박만영
Original Assignee
주식회사 포스코
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 포스코 filed Critical 주식회사 포스코
Priority to KR1020010081210A priority Critical patent/KR100545086B1/en
Publication of KR20030050704A publication Critical patent/KR20030050704A/en
Application granted granted Critical
Publication of KR100545086B1 publication Critical patent/KR100545086B1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C21D8/0236—Cold rolling
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • 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

Landscapes

  • 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 랭크포드값이 높고 균일 연신율이 우수한 인장강도 35kgf/㎟급의 냉연강판과 아연도금강판의 제조방법에 관한 것으로,The present invention relates to a method of manufacturing a cold rolled steel sheet and a galvanized steel sheet having a tensile strength of 35kgf / mm2 grade excellent in uniform elongation,

중량 %로, C:0.0005∼0.0040%, N:0.0040%이하, S:0.008%이하, Mn:0.6∼1.0%, P:0.04∼0.07%, 산가용Al:0.1∼0.2%이고 유효Ti(Ti*)=Ti(wt%)-[N(wt%)×(48÷14) + C(wt%)×(48÷12)]이고 Ti*가 0이하일 경우에 유효Nb(Nb*)=Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 하는 Ti: Ti*~0.03%, Nb:0.015%이하이며 또는 B:0.0015%이하를 함유하며 잔부 Fe및 기타 불가피하게 함유되는 원소를 포함한 극저탄소강과; By weight%, C: 0.0005 to 0.0040%, N: 0.0040% or less, S: 0.008% or less, Mn: 0.6 to 1.0%, P: 0.04 to 0.07%, acid value Al: 0.1 to 0.2%, and effective Ti (Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14) + C (wt%) × (48 ÷ 12)] and valid when Ti * is less than or equal to Nb (Nb *) = Nb Ti: Ti * to 0.03%, Nb: 0.015% or less, or B: 0.0015% or less, and the balance Fe to make Nb *> 0 under the condition of (wt%) + [Ti * × (93 ÷ 48)] And very low carbon steels containing other inevitable elements;

또한 이 극저탄소강을 통상의 방법으로 슬래브 재가열을 실시하고 열간압연하되, 열간 마무리 압연온도를 Ar3 변태점이상으로 하여 450∼700℃의 범위에서 권취하여 열연코일을 제조하고, 통상의 방법으로 산세하고 냉간압연을 60%이상 행한 후 소둔을 재결정온도이상 Ac3이하에서 실시하고 과시효처리를 행함에 의해서 냉연강판을 제조하고, 또한 아연도금강판은 상기 소둔 열처리후 아연도금욕을 통과함에 의하여 제조함을 요지로 한다.In addition, the ultra-low carbon steel is subjected to reheating of the slab in a conventional manner and hot rolled. The hot-rolled coil is manufactured by winding in a range of 450 to 700 ° C. with the hot finish rolling temperature above the Ar3 transformation point, and pickling by a conventional method. After cold rolling 60% or more, the annealing is carried out below the recrystallization temperature Ac3 or less and subjected to overaging treatment to produce a cold rolled steel sheet, and the galvanized steel sheet is manufactured by passing through a galvanizing bath after the annealing heat treatment. Make a point.

극저탄소강, 드로잉성, 장출성형성, 냉연강판Ultra low carbon steel, drawing, sheet forming, cold rolled steel

Description

드로잉성 및 장출 성형성이 향상되는 극저탄소강과 이를 이용한 고강도 냉연 또는 아연도금강판의 제조방법{Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability} Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability}             

도 1은 본 발명의 알루미늄 첨가에 따른 소둔후의 재질특성을 나타낸 그래프.1 is a graph showing the material properties after annealing according to the aluminum addition of the present invention.

도 2는 본 발명의 니오븀 첨가에 따른 소둔후의 랭크포드값 특성을 나타낸 그래프.Figure 2 is a graph showing the Rankford value characteristics after annealing according to the addition of niobium of the present invention.

본 발명은 드로잉성 및 장출 성형성이 향상되는 극저탄소강과 이를 이용한 고강도 냉연 및 아연도금강판의 제조방법에 관한 것이며, 보다 상세히는 랭크포드값(이하 rm값이라 함)이 높고 균일 연신율이 우수한 인장강도 35kgf/㎟급의 냉연강판과 아연도금강판의 제조방법에 관한 것이다.The present invention relates to a method for producing ultra-low carbon steel and a high-strength cold-rolled and galvanized steel sheet using the same, the drawing properties and elongated formability, more specifically, high Rankford value (hereinafter referred to as r m value) and excellent uniform elongation The present invention relates to a cold rolled steel sheet having a tensile strength of 35 kgf / mm 2 and a galvanized steel sheet.

일반적으로 냉연 및 표면처리 제품에서의 고강도강이라 함은 인장강도가 35kgf/㎟이상인 강판을 얘기하는데, 이와 같은 고강도 강판을 사용하여 자동차를 생산할 경우 강판의 두께를 낮출수 있기 때문에 에너지 소비를 대폭적으로 줄일 수 있는 효과가 있을 뿐만 아니라 자동차의 안정성 측면에서도 유리한 점이 있으나 성형성이 낮아 자동차 내,외판에 적용되는 부위가 한정되어 있다. In general, high-strength steel in cold-rolled and surface-treated products refers to a steel plate with a tensile strength of 35kgf / mm2 or more. When using a high-strength steel sheet to produce automobiles, the thickness of the steel sheet can be reduced, which greatly reduces energy consumption. Not only is there an effect that can be reduced, but there is an advantage in terms of stability of the automobile, but the moldability is low, and the parts applied to the interior and exterior of the automobile are limited.

프레스 성형성이 우수하기 위해서는 r값과 연신율이 높은 것이 바람직한데, 강도 확보를 위하여 첨가하는 Mn, Si, P등에 의한 입계 편석 및 전위 이동에 대한 장애물로써의 영향등에 의해 연신율은 일반적으로 감소한다. 또한 가공성 확보를 위하여 극저탄소강에 Ti, Nb등을 첨가하여 고용 원소(탄소 혹은/그리고 질소)를 탄질화물로 석출시켜 강을 IF(Interstitial Free)강으로 만드는 것이 일반적인 방법인데, Ti의 경우는 강도 확보를 위해 첨가되는 P 및 Fe와 결합하여 FeTiP를 이루는데 이러한 석출물들은 강의 rm값과 연신율에 악영향을 미친다. In order to have excellent press formability, it is desirable to have a high r value and a high elongation. The elongation generally decreases due to influences as an obstacle to grain boundary segregation and dislocation movement due to Mn, Si, and P added for securing strength. In addition, in order to secure workability, it is common to add Ti, Nb, etc. to ultra-low carbon steel to precipitate solid solution element (carbon or / and nitrogen) as carbonitride to make steel into IF (Interstitial Free) steel. FeTiP is combined with P and Fe added to secure strength, and these precipitates adversely affect the r m value and elongation of the steel.

일반적으로 P첨가량을 낮추거나 권취온도를 500℃이하로 하여 FeTiP석출물의 형성을 억제하여야 하는데, 전자는 강도 확보 측면에서 불리하며, 후자는 열연 권취 형상 및 작업성에서 아주 불리하며 이후의 소둔에서 재석출하는 단점도 있다. In general, the amount of P added or the winding temperature should be less than 500 ℃ to suppress the formation of FeTiP precipitates, the former is disadvantageous in terms of securing strength, the latter is very disadvantageous in the shape of hot rolled and workability, and re-prepared in subsequent annealing There are also disadvantages to shipping.

상기 IF강에서 연신율 증가를 위한 특허인 일본 특개평 9-118955호의 경우는 위의 문제를 해결하기 위해 Al량을 0.04~0.1%의 범위로 첨가해서 FeTiP의 미세 석출물의 수를 낮춤에 의해 연신율을 증가시키고 있는데, 이는 강도의 하락도 함께 수반하는 단점이 있으며, 또한, Materia 2000년 12월호(p944)에 의하면 Ti대신에 Zr을 첨가함에 따라서 FeTiP석출물을 완전 제거하여 연신율을 증가시킬 수 있음을 보고하고 있으나, 이는 제강 원단위의 급격한 증가를 수반한다.In the case of Japanese Patent Laid-Open No. 9-118955, which is a patent for increasing the elongation in the IF steel, in order to solve the above problem, the elongation is reduced by adding Al in a range of 0.04 to 0.1% by lowering the number of fine precipitates of FeTiP. This is accompanied by a decrease in strength, and also according to the December 2000 issue of Materia (p944), it is possible to increase the elongation by completely removing FeTiP precipitates by adding Zr instead of Ti. However, this entails a sharp increase in the steelmaking unit.

본발명은 상기 설명한 종래기술의 문제를 해결하기 위하여 창안한 것으로, FeTiP등의 석출물의 형성을 억제하기 위해 P를 낮추거나 권취온도를 낮추는 것이 아니라, Ti양을 낮추고 이의 보상을 위하여 Nb을 복합 첨가함에 의하여 FeTiP의 석출을 실질적으로 억제하고, Al을 다량 첨가함에 의해 FeTiP 석출물의 양을 줄임과 동시에 고용강화를 이루어 강도를 보상함으로서 rm값이 높고 균일 연신율이 우수한 인장강도 35kgf/㎟급의 극저탄소강과 이를 이용한 냉연강판 또는 아연도금강판의 제조방법을 제공하는데 그 목적이 있다.
The present invention was devised to solve the above-described problems of the prior art, and in order to suppress the formation of precipitates such as FeTiP, it is not lowering P or lowering the coiling temperature, but lowering the amount of Ti and adding Nb for the compensation thereof. as substantially inhibit the precipitation of FeTiP and, Al a large amount was added as the pole of FeTiP precipitate by both reduction and at the same time made the solid solution strengthening compensate for the intensity of r m value is high and is excellent in uniform elongation tensile strength of 35kgf / ㎟ class of by by Its purpose is to provide a low carbon steel and a method for producing a cold rolled steel sheet or a galvanized steel sheet using the same.

상기 목적을 달성하기 위한 본 발명은 드로잉성 및 장출 성형성이 향상되는 극저탄소강과 이를 이용한 고강도 냉연 및 아연도금강판의 제조방법에 있어서, 중량 %로, C:0.0005∼0.0040%, N:0.0040%이하, S:0.008%이하, Mn:0.6∼1.0%, P:0.04∼0.07%, 산가용Al:0.1∼0.2%이고 유효Ti(Ti*)=Ti(wt%)- [N(wt%)×(48÷14) + C(wt%)×(48÷12)]이고 Ti*가 0이하일 경우에 유효Nb(Nb*)=Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 하는 Ti: Ti*~0.03%, Nb:0.015%이하이며 또는 B:0.0015%이하를 함유하며 잔부 Fe및 기타 불가피하게 함유되는 원소를 포함한 극저탄소강과; In order to achieve the above object, the present invention provides a very low carbon steel and a high strength cold rolled and galvanized steel sheet using the same, which are improved in drawing property and elongation formability, in terms of weight%, C: 0.0005 to 0.0040%, N: 0.0040% S: 0.008% or less, Mn: 0.6 to 1.0%, P: 0.04 to 0.07%, acid value Al: 0.1 to 0.2%, and effective Ti (Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14) + C (wt%) × (48 ÷ 12)] and effective when Ti * is less than or equal to Nb (Nb *) = Nb (wt%) + [Ti * × (93 ÷ 48)] Ultra low carbon steel containing Ti: Ti * ~ 0.03%, Nb: 0.015% or less, or B: 0.0015% or less and containing the balance Fe and other unavoidably contained elements such that Nb * >

또한 이 극저탄소강을 통상의 방법으로 슬래브 재가열을 실시하고 열간압연하되, 열간 마무리 압연온도를 Ar3 변태점이상으로 하여 450∼700℃의 범위에서 권취하여 열연코일을 제조하고, 통상의 방법으로 산세하고 냉간압연을 60%이상 행한 후 소둔을 재결정온도이상 Ac3이하에서 실시하고 과시효처리를 행함에 의해서 냉연강판을 제조하고, 또한 아연도금강판은 상기 소둔 열처리후 아연도금욕을 통과함에 의하여 제조함을 특징으로 하는 고강도 냉연 및 아연도금강판의 제조방법을 제공한다.In addition, the ultra-low carbon steel is subjected to reheating of the slab in a conventional manner and hot rolled. The hot-rolled coil is manufactured by winding in a range of 450 to 700 ° C. with the hot finish rolling temperature above the Ar3 transformation point, and pickling by a conventional method. After cold rolling 60% or more, the annealing is carried out below the recrystallization temperature Ac3 or less and subjected to overaging treatment to produce a cold rolled steel sheet, and the galvanized steel sheet is manufactured by passing through a galvanizing bath after the annealing heat treatment. It provides a method of manufacturing a high strength cold rolled and galvanized steel sheet characterized in.

이하에서는 양호한 실시예와 관련하여 본 발명을 상세하게 설명한다.Hereinafter, the present invention will be described in detail with reference to the preferred embodiments.

본 발명의 드로잉성 및 장출 성형성이 향상되는 극저탄소강의 성분조성은 중량 %로, C:0.0005∼0.0040%, N:0.0040%이하, S:0.008%이하, Mn:0.6∼1.0%, P:0.04∼0.07%, 산가용Al:0.1∼0.2%이고 유효Ti(Ti*)= Ti(wt%)- [N(wt%)×(48÷14) + C(wt%)×(48÷12)]이고 Ti*가 0이하일 경우에 유효Nb(Nb*)= Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 하는 Ti: Ti*~0.03%, Nb:0.015%이하이며 또는 B:0.0015%이하를 함유하며 잔부 Fe및 기타 불가피하게 함유되는 원소를 포함하는 것을 특징으로 한다.The composition of the ultra-low carbon steel which improves the drawability and elongation moldability of the present invention is in weight%, C: 0.0005 to 0.0040%, N: 0.0040% or less, S: 0.008% or less, Mn: 0.6 to 1.0%, P: 0.04 to 0.07%, acid value Al: 0.1 to 0.2%, and effective Ti (Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14) + C (wt%) × (48 ÷ 12 )] And effective when Ti * is less than or equal to 0. Ti to make Nb *> 0 under the condition of Nb (Nb *) = Nb (wt%) + [Ti * × (93 ÷ 48)]: Ti * to 0.03% , Nb: 0.015% or less or B: 0.0015% or less, and the balance Fe and other inevitable elements.

이에 대한 각 성분의 수치 한정 이유를 설명하면 다음과 같다.The reason for numerical limitation of each component is as follows.

상기 C는 가공성을 저해하는 원소로 알려져있어 고가공성이 요구되는 제품의 경우 극저탄소강으로 생산하고 있으며, 이에 따라 통상의 극저탄소강 생산에서 얻어지는 조성으로 제한하였다.The C is known as an element that inhibits the workability, and in the case of a product requiring high workability, the C is produced as an ultra low carbon steel, and thus, the C is limited to a composition obtained in ordinary ultra low carbon steel production.

상기 Mn과 S는 에지크랙을 일으키는 FeS의 형성을 방지하기 위해 Mn은 S함량에 대해 통상 약 10배이상이 함유되어야 하는데, 본 발명의 조성은 이를 만족한다. Mn의 경우에 고용강화를 시키기 위해서는 다량 함유되는 것이 강도증가의 측면에서 유리하나, Mn의 입계 편석에 의한 연신율 하락도 우려되므로 상한을 1.0%이하로 설정하였고, Mn성분의 하한은 인장강도 35kgf/㎟을 확보하기 위하여 0.6%이상으로 설정되었다.In order to prevent the formation of FeS which causes edge cracks of Mn and S, Mn should generally be contained in an amount of about 10 times or more with respect to S content, and the composition of the present invention satisfies this. In the case of Mn, it is advantageous to contain a large amount in order to increase the solid solution in terms of strength, but the upper limit is set to 1.0% or less because the elongation may be lowered due to Mn grain boundary segregation, and the lower limit of Mn component is 35kgf / It was set at 0.6% or more to secure mm 2.

상기 P는 소량첨가에 의해서도 고용강화 효과가 탁월한 원소이므로 다량 첨가하는 것이 바람직하나, 다량 첨가시 입계취하에 의한 DBTT(Ductile Brittle Transition Temperature)가 높아짐에 따른 2차 가공취성이 우려되며 FeTiP형성 측면에서도 불리하므로 상한을 0.07%이하로 설정하였고, 하한은 인장강도 35kgf/㎟을 확보하기 위하여 0.04%이상으로 제한하였다.Since P is an element having an excellent solid solution effect even by a small amount of addition, it is preferable to add a large amount. However, when a large amount is added, secondary processing brittleness is a concern due to an increase in DBTT (Ductile Brittle Transition Temperature) due to grain boundary bleeding. The upper limit was set to 0.07% or less, and the lower limit was limited to 0.04% or more in order to secure a tensile strength of 35kgf / mm 2.

상기 B은 강판의 적용 용도 혹은 적용 부문에 따라 우려되는 P편석에 의한 2차가공취성을 방지하기 위하여 첨가를 행하며, r값등의 열화를 막기위하여 상한을 0.0015%이하로 설정하였다.The above-mentioned B is added to prevent secondary work brittleness due to P segregation, which is concerned according to the application use or application section of the steel sheet, and the upper limit is set to 0.0015% or less to prevent deterioration such as r value.

상기 N의 경우도 C와 마찬가지로 통상의 극저탄소강 생산에서 얻어지는 조성으로 제한하였다.N was also limited to the composition obtained in normal ultra low carbon steel production as in C.

상기 Ti는 C와 N등의 침입형 고용원소등이 가공성을 저해하므로 이를 석출시킬 수 있는 양, 즉 유효Ti(Ti*)= Ti(wt%)- [N(wt%)×(48÷14) + C(wt%)×(48÷12)] 이 하한으로 첨가되어야 한다. 전술한 바와 같이 연신율과 r값에 악영향을 미치는 FeTiP를 석출시키지만 0.03% 이하로 첨가될 경우 석출이 거의 이루어지지 않으므로 상한을 설정하였으며, 이 Ti함량은 항복강도를 높이는 것(24kgf/㎟이상일 경우에 판재 성형시 면 불량을 발생시키는 것으로 알려짐)으로 알려진 고용 C와 N를 TiC와 TiN의 형태로 기지에서 제거하는 역할을 한다.Since Ti is an invasive solid-solution element such as C and N, the workability is impaired, that is, the amount that can precipitate it, that is, effective Ti (Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14 ) + C (wt%) x (48 ÷ 12)] should be added as the lower limit. As described above, FeTiP, which adversely affects the elongation and r-value, is precipitated, but when it is added below 0.03%, precipitation is hardly achieved, so the upper limit is set, and the Ti content is to increase the yield strength (at least 24kgf / mm2). The solid solution C and N, which are known to cause surface defects in sheet forming, are removed from the matrix in the form of TiC and TiN.

Nb은 상기의 Ti에 의하여 C이 완벽하게 기지에서 제거되지 못하는 것을 방지하기 위하여 첨가되며, 즉 Ti*가 0이하일 경우에 유효Nb(Nb*)= Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 제한을 하고, 상한은 과다 첨가에 의한 연신율 하락과 재결정온도 상승을 방지하기 위하여 0.015%이하로 제한했다.Nb is added to prevent C from being completely removed from the matrix by the above Ti, that is, effective when Ti * is less than or equal to Nb (Nb *) = Nb (wt%) + [Ti * × (93 ÷ 48)], and the upper limit was limited to 0.015% or less in order to prevent the decrease of elongation due to excessive addition and the rise of recrystallization temperature.

상기 산가용 Al은 연신율의 향상이 안정적으로 확보되기 위하여 0.1% 이상으로 하한을 제한하였고 상한의 경우는 0.2% 초과의 첨가는 제강 원단위측면에서 불리하므로 제한하였다.The acid-soluble Al was limited to the lower limit to 0.1% or more in order to ensure the improvement of the elongation stably, and the upper limit in the case of the upper limit of more than 0.2% because it is disadvantageous in terms of the steelmaking unit.

본 발명에서는 상기 조성의 극저탄소강을 통상의 방법으로 슬래브 재가열을 실시하고 열간압연하되 열간 마무리 압연온도를 Ar3 변태점이상으로 하여 450∼700℃의 범위에서 권취하여 열연코일을 제조한다.In the present invention, the ultra-low carbon steel having the composition described above is subjected to slab reheating in a conventional manner and hot-rolled, but wound in a range of 450 to 700 ° C. with a hot finish rolling temperature above Ar3 transformation point to produce a hot rolled coil.

열연권취를 450∼700℃로 제한한 것은 450℃미만에서는 열연권취 작업이 어렵기 때문이며, 700℃초과의 경우는 산세 곤란한 산화막이 열연강판에 형성되므로 상기와 같이 제한하였다.The hot rolled winding was limited to 450 to 700 ° C. because the hot rolled winding operation was difficult at 450 ° C. or lower, and in the case of over 700 ° C., an oxide film which was difficult to pickle was formed on the hot rolled steel sheet.

상기와 같이 열연권취하여 열연코일을 제조한 후 통상의 경우와 같이 산세를 행하고 60%이상의 냉간압연을 행한후 냉연강판의 경우에는 소둔을 재결정온도이상 Ac3이하에서 실시하고 과시효처리를 행함에 의해 제조하고 아연도금강판의 경우에는 소둔 열처리후 아연 도금욕을 통과함에 의하여 제조한다. After the hot rolled coil is manufactured by hot rolling as described above, pickling is carried out as usual, followed by cold rolling of 60% or more, and in the case of cold rolled steel sheets, annealing is performed at a recrystallization temperature or higher and Ac3 or lower, and overaging treatment. In the case of the galvanized steel sheet is manufactured by passing through a galvanizing bath after annealing heat treatment.

이하에서는 실시예를 통하여 본 발명을 보다 상세하게 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

[실시예]EXAMPLE

진공유도로에 의해 표 1에 나타낸 조성의 극저탄소강 강괴를 두께 60mm, 폭 175mm로 제조하고 1200℃에서 1시간 재가열을 실시한 후 9패스(pass)로 2.8mm 두께가 되도록 열간압연을 하였다. 열간압연 마무리 온도는 Ar3 변태점이상으로 하였다. 이어서, 열연권취는 550℃, 650℃로 미리 가열된 로에 1시간 유지후 로냉시키는 모사실험으로 행하였다. 냉간압연은 압하율 75%로 하여 최종 두께 0.7mm가 되도록 실시하였으며, 연속소둔 열처리는 적외선 가열장치를 이용하였다.The ultra low carbon steel ingots of the composition shown in Table 1 were prepared by a vacuum induction in a thickness of 60 mm and a width of 175 mm, and reheated at 1200 ° C. for 1 hour, and then hot rolled to a thickness of 2.8 mm in 9 passes. Hot rolling finish temperature was made into the Ar3 transformation point or more. Subsequently, hot rolling was carried out by a simulation experiment in which a furnace was cooled to 550 ° C. and preheated to 650 ° C. for 1 hour and then cooled. Cold rolling was carried out to a final thickness of 0.7 mm with a reduction ratio of 75%. The continuous annealing heat treatment was performed using an infrared heater.

wt%wt% CC MnMn PP SS Sol AlSol Al TiTi NbNb NN BB Ti*Ti * Nb*Nb * 비교1Comparison 1 0.00210.0021 0.630.63 0.0510.051 0.00660.0066 0.0360.036 0.0100.010 0.0050.005 0.00160.0016 -- -0.004-0.004 -0.0025-0.0025 비교2Comparison 2 0.00200.0020 0.670.67 0.0520.052 0.00670.0067 0.0340.034 0.0350.035 0.0100.010 0.00190.0019 -- 0.0200.020 0.01000.0100 비교3Comparison 3 0.00190.0019 0.640.64 0.0520.052 0.00680.0068 0.0430.043 0.0100.010 0.0090.009 0.00150.0015 -- -0.003-0.003 0.00370.0037 비교4Comparison 4 0.00210.0021 0.660.66 0.0500.050 0.00670.0067 0.0550.055 0.0200.020 0.0110.011 0.00140.0014 -- 0.0070.007 0.01100.0110 비교5Comparison 5 0.00190.0019 0.690.69 0.0520.052 0.00680.0068 0.0740.074 0.0200.020 0.0090.009 0.00210.0021 -- 0.0050.005 0.00900.0090 발명1Inventive 1 0.00210.0021 0.690.69 0.0510.051 0.00590.0059 0.1210.121 0.0210.021 0.0090.009 0.00210.0021 -- 0.0050.005 0.00900.0090 발명2Inventive 2 0.00260.0026 0.710.71 0.0500.050 0.00620.0062 0.1800.180 0.0200.020 0.0050.005 0.00170.0017 -- 0.0040.004 0.00500.0050 발명3Inventive 3 0.00210.0021 0.730.73 0.0610.061 0.00500.0050 0.1180.118 0.0250.025 0.0050.005 0.00070.0007 0.00080.0008 0.0140.014 0.00500.0050

구 분division 권취온도 (℃)Winding temperature (℃) 항복강도 (kgf/㎟)Yield strength (kgf / ㎡) 인장강도 (kgf/㎟)Tensile Strength (kgf / ㎡) 균일 연신율 (%)Uniform elongation (%) 총연신율 (%)Total Elongation (%) rm값r m value 비교1Comparison 1 550550 21.9221.92 34.7834.78 23.0123.01 42.3042.30 1.9101.910 비교2Comparison 2 550550 22.7922.79 35.2635.26 22.8022.80 41.3541.35 2.0382.038 650650 22.3422.34 35.3035.30 23.2023.20 40.6540.65 2.1452.145 비교3Comparison 3 650650 23.5423.54 35.1035.10 22.9222.92 39.6439.64 2.1582.158 비교4Comparison 4 550550 20.3020.30 34.9334.93 23.4023.40 42.6042.60 2.0882.088 650650 21.3021.30 35.1035.10 23.1923.19 41.9741.97 2.2682.268 비교5Comparison 5 550550 21.7821.78 34.8134.81 24.2324.23 43.1443.14 2.1272.127 발명1Inventive 1 550550 21.2221.22 35.2435.24 25.8025.80 45.1845.18 2.1032.103 650650 22.5122.51 35.4035.40 25.3025.30 44.7044.70 2.0572.057 발명2Inventive 2 650650 21.5021.50 35.5035.50 25.4025.40 44.8044.80 2.0472.047 발명3Inventive 3 650650 22.2022.20 35.5135.51 25.2025.20 44.2044.20 2.2702.270

소둔 열처리 후의 재질 특성을 표 2와 도 1, 도 2에 나타내었다. The material properties after the annealing heat treatment are shown in Table 2 and FIGS. 1 and 2.

도 1은 본 발명의 알루미늄 첨가에 따른 소둔후의 재질특성을 나타낸 그래프이고, 도 2는 본 발명의 니오븀 첨가에 따른 소둔후의 랭크포드값 특성을 나타낸 그래프이다.1 is a graph showing the material properties after annealing according to the addition of aluminum of the present invention, Figure 2 is a graph showing the Rankford value characteristics after annealing according to the niobium addition of the present invention.

표 2에서 알 수 있듯이 본 발명강(1∼3)은 비교강(1∼5)에 비해 rm값은 2.047이상을 나타며 동등수준을 보이고 있다. 이는 rm값이 2.0보다 크면 성형성이 매우 좋다고 할 수 있기 때문에 드로잉성이 우수함을 알 수 있다. 다만 비교강(1)의 경우 Sol.Al, Ti* 및 Nb*함량이 본 발명의 범위를 벗어나므로 rm값이 약간 낮음을 알 수 있다. 또한 장출성형성 지표를 나타낼 수 있는 균일 연신율과 총 연신율에 있어서는 상기 본 발명의 강이 비교강에 비해 크게 우수하다. 이는 도 1에 나타낸 바와 같이 Sol.Al의 함량에 기인한 것으로 판단된다.As can be seen from Table 2, the inventive steels (1 to 3) have an r m value of 2.047 or more, and are equivalent to those of the comparative steels (1 to 5). This indicates that the moldability is very good when the r m value is larger than 2.0, and thus the drawing property is excellent. However, in the case of the comparative steel (1), since the Sol.Al, Ti * and Nb * content is outside the scope of the present invention, it can be seen that the value of r m is slightly low. In addition, the steel of the present invention is significantly superior to the comparative steel in the uniform elongation and the total elongation that can indicate the elongation-forming property index. This is believed to be due to the content of Sol.Al as shown in FIG.

도 1에서 알 수 있듯이 Al양이 증가함에 따라 균일 연신율과 총연신율이 증가하는데 0.06%이상에서 증가하기 시작을 하나 안정적인 확보를 위해서는 0.1%이상 의 첨가가 요구되며, 0.2%를 초과하면 포화되는 것을 알수가 있다. As can be seen in Figure 1, as the amount of Al increases, uniform elongation and total elongation begin to increase at 0.06% or more, but more than 0.1% is required to ensure stability, and if it exceeds 0.2%, it is saturated. I can tell.

도 2는 Nb*를 0이상으로 제어함에 의해 rm값을 평균 수준 이상으로 확보할 수 있으며, 0.004%이상에서는 고 rm값을 확보할 수 있음을 보여주고 있다.2 shows that the value of r m can be secured to an average level or more by controlling Nb * to 0 or more, and a value of high r m can be obtained at 0.004% or more.

상술한 바와 같이, 본 발명의 취지에 따라서 합금성분을 설계하고 이를 열연, 냉연, 소둔의 공정에 따라 강판을 생산하면 인장강도 35kgf/㎟급에서 드로잉성과 장출 성형성이 우수한 냉연강판과 아연도금강판 을 생산할 수 있다. As described above, if the alloy component is designed in accordance with the spirit of the present invention and the steel sheet is produced according to the process of hot rolling, cold rolling and annealing, the cold rolled steel sheet and the galvanized steel sheet having excellent drawing property and elongation formability at a tensile strength of 35kgf / mm2 grade Can produce

상기 설명한 바와 같이 본 발명에 의하면, 적절한 합금성분을 설계하고, 열간압연 및 연속소둔조건을 적절히 제어함으로써 인장강도 35kgf/㎟급의 드로잉성과 장출 성형성이 우수한 냉연강판과 아연도금강판을 생산할 수 있는 효과를 가지며, 자동차 및 가전등에 유용한 용도로 적용 확대가 가능하다.
As described above, according to the present invention, by designing an appropriate alloy component, and appropriately controlling the hot rolling and continuous annealing conditions, it is possible to produce cold rolled steel sheet and galvanized steel sheet excellent in drawing property and elongation formability of 35kgf / mm2 tensile strength. It has an effect and can be extended to be used for automobiles and home appliances.

Claims (3)

드로잉성 및 장출 성형성이 향상되는 극저탄소강에 있어서,In the ultra low carbon steel which improves drawability and elongation formability, 중량 %로, C:0.0005∼0.0040%, N:0.0040%이하, S:0.008%이하, Mn:0.6∼1.0%, P:0.04∼0.07%, 산가용Al:0.1∼0.2%이고, 유효Ti(Ti*)=Ti(wt%)- [N(wt%)×(48÷14) + C(wt%)×(48÷12)]이고 Ti*가 0이하일 경우에 유효Nb(Nb*)=Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 하는 Ti: Ti*~0.03%, Nb:0.015%이하를 함유하며 잔부 Fe및 기타 불가피하게 함유되는 원소를 포함한 것을 특징으로 하는 극저탄소강.In weight%, C: 0.0005 to 0.0040%, N: 0.0040% or less, S: 0.008% or less, Mn: 0.6 to 1.0%, P: 0.04 to 0.07%, acid value Al: 0.1 to 0.2%, and effective Ti ( Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14) + C (wt%) × (48 ÷ 12)] and is effective when Ti * is less than or equal to Nb (Nb *) = Ti: Ti * ~ 0.03%, Nb: 0.015% or less, and the balance Fe and other unavoidably contained Nb (wt%) + [Ti * × (93 ÷ 48)] to make Nb *> 0. Ultra-low carbon steel, characterized in that it contains an element. 제1항에 있어서, 상기 조성의 강에 0.0015%이하의 B을 더 함유하는 것을 특징으로 하는 극저탄소강.The ultra low carbon steel according to claim 1, further comprising B of 0.0015% or less in the steel of the composition. 고강도 냉연 및 아연도금강판의 제조방법에 있어서,In the manufacturing method of high strength cold rolled and galvanized steel sheet, 중량 %로, C:0.0005∼0.0040%, N:0.0040%이하, S:0.008%이하, Mn:0.6∼1.0%, P:0.04∼0.07%, 산가용Al:0.1∼0.2%이고 유효Ti(Ti*)=Ti(wt%)- [N(wt%)×(48÷14) + C(wt%)×(48÷12)]이고 Ti*가 0이하일 경우에 유효Nb(Nb*)=Nb(wt%) +[Ti*×(93÷48)]의 조건에서 Nb* > 0이 되도록 하는 Ti: Ti*~0.03%, Nb:0.015%이 하를 함유하며 잔부 Fe및 기타 불가피하게 함유되는 원소를 포함하는 극저탄소강을 통상의 방법으로 슬래브 재가열을 실시하고 열간압연하되, 열간 마무리 압연온도를 Ar3 변태점이상으로 하여 450∼700℃의 범위에서 권취하여 열연코일을 제조하고, 통상의 방법으로 산세하고 냉간압연을 60%이상 행한 후 소둔을 재결정온도이상 Ac3이하에서 실시하고 과시효처리를 행함에 의해서 냉연강판을 제조하고, 또한 아연도금강판은 상기 소둔 열처리후 아연도금욕을 통과함에 의하여 제조함을 특징으로 하는 드로잉성과 장출 성형성이 향상되는 고강도 냉연 및 아연도금강판의 제조방법.By weight%, C: 0.0005 to 0.0040%, N: 0.0040% or less, S: 0.008% or less, Mn: 0.6 to 1.0%, P: 0.04 to 0.07%, acid value Al: 0.1 to 0.2%, and effective Ti (Ti *) = Ti (wt%)-[N (wt%) × (48 ÷ 14) + C (wt%) × (48 ÷ 12)] and valid when Ti * is less than or equal to Nb (Nb *) = Nb (wt%) + [Ti * × (93 ÷ 48)] in the condition of Nb *> 0, Ti: Ti * ~ 0.03%, Nb: 0.015% or less, the balance Fe and other unavoidably The slab reheat is heated in a conventional manner, and the hot rolled slab is rolled in a conventional manner, and the hot rolled coil is wound in the range of 450 to 700 ° C. with the hot finish rolling temperature above the Ar3 transformation point to produce a hot rolled coil. After pickling and cold rolling 60% or more, annealing is carried out at the recrystallization temperature or higher Ac3 or less and overaging treatment to produce a cold rolled steel sheet, and the galvanized steel sheet is manufactured by passing the galvanizing bath after the annealing heat treatment. Draw characterized by the ship Process for producing high strength cold rolled and galvanized steel sheet with improved ductility and elongation formability.
KR1020010081210A 2001-12-19 2001-12-19 Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability KR100545086B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020010081210A KR100545086B1 (en) 2001-12-19 2001-12-19 Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020010081210A KR100545086B1 (en) 2001-12-19 2001-12-19 Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability

Publications (2)

Publication Number Publication Date
KR20030050704A KR20030050704A (en) 2003-06-25
KR100545086B1 true KR100545086B1 (en) 2006-01-24

Family

ID=29576410

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020010081210A KR100545086B1 (en) 2001-12-19 2001-12-19 Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability

Country Status (1)

Country Link
KR (1) KR100545086B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110359001A (en) * 2019-08-31 2019-10-22 日照宝华新材料有限公司 A kind of process and its equipment for producing think gauge hot substrate and having colored galvanizing production

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101118284B1 (en) * 2003-12-29 2012-03-20 주식회사 포스코 Steel sheet with very good drawability and fabrication method thereof
CN111996457A (en) * 2020-08-27 2020-11-27 攀钢集团研究院有限公司 Method for producing cold-rolled steel plate by low-temperature continuous annealing

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05171353A (en) * 1991-07-30 1993-07-09 Nippon Steel Corp Steel sheet for deep drawing excellent in baking hardenability and its production
JPH08253840A (en) * 1995-03-16 1996-10-01 Kawasaki Steel Corp Thin steel sheet excellent in press formability and production thereof
JPH10183240A (en) * 1996-12-20 1998-07-14 Kawasaki Steel Corp Material sheet for surface treatment, hot rolled steel sheet for the same and their production
JPH10183253A (en) * 1996-12-24 1998-07-14 Nisshin Steel Co Ltd Production of cold rolled steel sheet or hot dip plated steel sheet excellent in surface property and workability

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05171353A (en) * 1991-07-30 1993-07-09 Nippon Steel Corp Steel sheet for deep drawing excellent in baking hardenability and its production
JPH08253840A (en) * 1995-03-16 1996-10-01 Kawasaki Steel Corp Thin steel sheet excellent in press formability and production thereof
JPH10183240A (en) * 1996-12-20 1998-07-14 Kawasaki Steel Corp Material sheet for surface treatment, hot rolled steel sheet for the same and their production
JPH10183253A (en) * 1996-12-24 1998-07-14 Nisshin Steel Co Ltd Production of cold rolled steel sheet or hot dip plated steel sheet excellent in surface property and workability

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110359001A (en) * 2019-08-31 2019-10-22 日照宝华新材料有限公司 A kind of process and its equipment for producing think gauge hot substrate and having colored galvanizing production

Also Published As

Publication number Publication date
KR20030050704A (en) 2003-06-25

Similar Documents

Publication Publication Date Title
KR102020404B1 (en) Steel sheet having ultra high strength and superior ductility and method of manufacturing the same
KR100711356B1 (en) Steel Sheet for Galvanizing with Superior Formability and Method for Manufacturing the Steel Sheet
JP3569949B2 (en) Method of manufacturing thin steel sheet for processing with excellent bake hardenability and aging resistance
KR101143151B1 (en) High strength thin steel sheet having excellent elongation and method for manufacturing the same
JP3528716B2 (en) High-strength cold-rolled steel sheet, high-strength galvanized steel sheet excellent in surface properties and press formability, and manufacturing method thereof
JP4177477B2 (en) Manufacturing method of cold-rolled steel sheet and hot-dip galvanized steel sheet with excellent room temperature aging resistance and panel characteristics
KR100545086B1 (en) Manufacturing method for high strength cold rolled and zinc coated steel sheets with good drawability and stretch flangability
KR101360486B1 (en) Zinc plated steel sheet having excellent coating quality, high ductility, and ultra high strength and method for manufacturing the same
JPH055887B2 (en)
KR20140086273A (en) High strength galvannealed steel sheet having excellent formability and coating adhesion and method for manufacturing the same
KR101185233B1 (en) Extremely low carbon hot-rolled steel for cold rolling with excelent acid-cleaning characteristic and compactibility and method of manufacturing the same
JP2671726B2 (en) Manufacturing method of cold rolled steel sheet for ultra deep drawing
KR101657799B1 (en) Galvanized steel sheet having excellent elogation and method for manufacturing the same
KR100829682B1 (en) Manufacturing method for high strength cold rolled steel sheet with good elongation
KR100368233B1 (en) Manufacturing method of high strength cold rolled steel sheet with excellent formability
KR20010059365A (en) a high strength cold rolled steel sheet with high formability and the method of manufacturing the same
KR101125916B1 (en) Non-aging cold rolled steel sheet having less anisotropy and process for producing the same
KR101153659B1 (en) A cold rolled steel sheet having excellent formability and coatability, and A method for manufacturing the same
KR100276327B1 (en) The manufacturing method of 60kg grade high strength cold rolling steel sheet with having zinc plating and ductility
KR100544737B1 (en) Blackplates with excellent formability and method for manufacturing thereof
KR100544724B1 (en) Cold Rolled Steel Sheet with Superior Workability and Method for Manufacturing the Sheet
KR100276329B1 (en) The manufacturing method of high strength cold rolling steel sheet with having excellent zinc plating property
KR100478659B1 (en) Producing method of cold rolled soft steel plate having deep drawing quality
KR101149288B1 (en) Method for producing of steel sheet having good surface quality
KR100400868B1 (en) BH cold rolled steel with excellent machinability and its manufacturing method

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20121231

Year of fee payment: 8

FPAY Annual fee payment

Payment date: 20140102

Year of fee payment: 9

FPAY Annual fee payment

Payment date: 20150109

Year of fee payment: 10

FPAY Annual fee payment

Payment date: 20160111

Year of fee payment: 11

FPAY Annual fee payment

Payment date: 20170105

Year of fee payment: 12

FPAY Annual fee payment

Payment date: 20190115

Year of fee payment: 14