KR20100047018A - Quenched hot-rolled steel sheet with excellent coating adhesion, and method for producing the same - Google Patents

Quenched hot-rolled steel sheet with excellent coating adhesion, and method for producing the same Download PDF

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KR20100047018A
KR20100047018A KR1020080106090A KR20080106090A KR20100047018A KR 20100047018 A KR20100047018 A KR 20100047018A KR 1020080106090 A KR1020080106090 A KR 1020080106090A KR 20080106090 A KR20080106090 A KR 20080106090A KR 20100047018 A KR20100047018 A KR 20100047018A
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steel sheet
silicon
weight
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added
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Korean (ko)
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이승하
김택준
도형협
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현대제철 주식회사
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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
    • 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
    • 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
    • C22C38/02—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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Abstract

PURPOSE: A thermal process cure type steel sheet with a superior plating adherence and a manufacturing method thereof are provided to secure platability and to make excellent martensite structure by cooling a cooling speed of 50~150°C. CONSTITUTION: A thermal process cure type steel sheet comprises nickel 0.01~2 weight%, aluminum 0.03 weight%, sulfur 0.05 weight%, carbon 0.19~0.40 weight%, manganese 0.5~2.5 weight%, chrome 0.1~0.5 weight%, boron 0.0015~0.0040 weight%, silicon 0.01~0.5 weight%, phosphorus 0.05 weight%, niobium 0.01~0.10 weight%, copper 0.01~1 weight%, and the two kind of iron for the rest. Molybdenum is added to 0.05~0.20 weight% according to the content of silicon.

Description

도금 부착성이 우수한 열처리 경화형 강판 및 그 제조방법{Quenched hot-rolled steel sheet with excellent coating adhesion, and method for producing the same}Quenched hot-rolled steel sheet with excellent coating adhesion, and method for producing the same}

본 발명은 열처리 경화형 강판 및 그 제조방법에 관한 것으로, 더욱 상세하게는 열간 프레스 가공 후에도 도금 부착성이 우수한 열처리 경화형 강판 및 그 제조방법에 관한 것이다.The present invention relates to a heat treated hardened steel sheet and a method of manufacturing the same, and more particularly, to a heat treated hardened steel sheet and a method of manufacturing the same even after hot press working.

최근 자동차 산업은 안전성 및 경량화 요구에 부응하기 위해 초고강도 강판의 적용이 증가하고 있다. 하지만 초고강도 강판의 경우 강판의 가공성형성이 저하되어 복잡한 형상으로의 가공이 필요한 자동차 부품에의 적용이 제한된다. Recently, the automotive industry is increasing the application of ultra-high strength steel sheet to meet the demand for safety and light weight. However, in the case of ultra-high strength steel sheet, the formability of the steel sheet is deteriorated, and thus the application to the automotive parts requiring processing into a complicated shape is limited.

따라서 강판을 가열하고 고온상태에서 프레스 성형을 한 후 급냉하여 고강도를 확보할 수 있도록 한 열처리 강화형 강판에 대한 요구가 높아지고 있다. Therefore, there is a growing demand for heat-treatment-enhanced steel sheets that are capable of securing high strength by heating the steel sheets and pressing them in a high temperature state and then quenching them.

열처리 경화형 강판은 보론(B)을 0.0005wt%이상 함유하고 탄소(C)와 망간(Mn)을 기본으로 한 소재를 900℃이상의 고온에서 프레스 성형하고 금형 내에서 급냉시켜 부품상태의 강도를 높이게 된다. Heat-treated hardened steel sheet contains more than 0.0005wt% of boron (B) and press-forms materials based on carbon (C) and manganese (Mn) at a high temperature of 900 ℃ or higher and rapidly cools them in a mold to increase the strength of parts. .

이러한 열처리 경화형 강판은 강도가 1,200MPa 이상으로 아주 높기 때문에 항복강도를 밀도로 나눈 비강도면에서 아주 우수하여 자동차의 경량화에 크게 기여할 수 있으며, 또한 가공 후 형상변형(Springback)이 거의 없어서 성형이 어려운 초고강도 요구 부품에 적용되고 있다. Since the heat-treated hardened steel sheet has a very high strength of 1,200 MPa or more, it is very excellent in terms of specific strength divided by yield strength, which can greatly contribute to the weight reduction of automobiles, and hard to form because there is almost no springback after processing. It is applied to high strength demanding parts.

그런데, 자동차용으로 개발되는 열처리 경화형 강판은 대부분 자동차의 프레임이나 충격 부재용으로 사용되므로 자동차의 충돌시 운전자 및 승객을 보호하기 위한 충격인성이 요구되고 있다. By the way, since the heat-treated hardened steel sheet developed for automobiles are mostly used for the frame or the impact member of the vehicle, impact toughness for protecting the driver and passengers during the collision of the vehicle is required.

따라서 국내 특허 2006-0018860에서는 탄소(C), 망간(Mn), 크롬(Cr), 티타늄(Ti), 보론(B)을 기본으로 하고 실리콘(Si), 인(P), 니오븀(Nb) 중 1종 또는 2종 이상을 추가로 함유한 강재를 성형 후의 금형 냉각시에 Ms(오스테나이트로부터 마르텐사이트가 생성되기 시작하는 온도)점 이하의 온도역에서의 평균 냉각속도를 일정 범위 내로 억제함으로써 열간 프레스 성형에 의해 안정된 강도와 인성을 겸비하도록 하고 있다. Therefore, domestic patent 2006-0018860 is based on carbon (C), manganese (Mn), chromium (Cr), titanium (Ti), boron (B), and among silicon (Si), phosphorus (P), niobium (Nb) The steel material further containing one or two or more kinds of steels is heated by suppressing the average cooling rate at a temperature range below the Ms (temperature at which martensite starts to form from austenite) during cooling of the mold after molding to within a predetermined range. By press molding, it is intended to have stable strength and toughness.

그리고, 일본 특개평8-269615호에서는 탄소(C), 실리콘(Si), 망간(Mn), 알루미늄(Al), 보론(B), 인(P)을 기본으로 한 강재에 구리(Cu), 니켈(Ni), 티타늄(Ti) 중 1종을 더 함유하여 강도와 인성을 확보하도록 하고 있다. In Japanese Patent Laid-Open No. 8-269615, carbon (C), silicon (Si), manganese (Mn), aluminum (Al), boron (B), phosphorus (P) based steels based on copper (Cu), Nickel (Ni) and titanium (Ti) are further contained to ensure strength and toughness.

하지만 상술한 종래의 열처리 경화형 강판들은 실리콘(Si), 망간(Mn), 인(P) 등의 난도금성 원소를 포함하므로 도금부착성이 낮아지는 문제점이 있다. However, the above-described conventional heat treatment hardened steel sheets include a non-plating element such as silicon (Si), manganese (Mn), phosphorus (P), and thus have a problem of low plating adhesion.

즉, 열간 프레스 성형시 난도금성 원소들이 강판표면으로 확산하여 강판표면에 잔류하게 되고, 그 중에서도 실리콘(Si)은 아연(Zn)보다 모재인 철(Fe)과의 친화력이 크므로 철-규소(Fe-Si)화합물을 형성하여 강판 표면에 산화막을 형성하게 된다. 따라서 열간 프레스 가공 후 내식성 향상을 위해 아연도금을 하더라도 도금부착성이 크게 낮아지는 문제점이 발생하고, 혹은 도금이 되더라도 도금밀착성을 열화시키는 문제점이 발생하는 것이다. That is, during hot press molding, non-plating elements diffuse to the steel plate surface and remain on the steel plate surface. Among them, silicon (Si) has a greater affinity with iron (Fe) than the base metal (Zn), so that iron-silicon ( Fe-Si) compound is formed to form an oxide film on the surface of the steel sheet. Therefore, even after galvanizing to improve the corrosion resistance after hot pressing work, there is a problem that the plating adhesion is significantly lowered, or even if the plating is a problem that degrades the plating adhesion.

본 발명은 상기한 바와 같은 종래의 문제점을 해결하기 위한 것으로, 본 발명의 목적은 실리콘(Si), 망간(Mn), 인(P) 등의 난도금성 원소가 첨가되는 강에서 몰리브덴(Mo)을 첨가하여 제조함으로써 열간 프레스 가공 후에도 도금 부착성이 확보되도록 한 도금부착성이 우수한 열처리 경화형 강판 및 그 제조방법을 제공하는 것이다. The present invention is to solve the conventional problems as described above, an object of the present invention is to provide molybdenum (Mo) in a steel to which non-plating elements such as silicon (Si), manganese (Mn), phosphorus (P) is added. The present invention provides a heat-treated hardened steel sheet having excellent plating adhesion to ensure plating adhesion even after hot press working, and a manufacturing method thereof.

상기한 목적을 달성하기 위한 본 발명의 특징에 따르면, 본 발명은 탄소(C) 0.19~0.40wt%, 망간(Mn) 0.5~2.5wt%, 크롬(Cr) 0.1~0.5wt%, 보론(B) 0.0015~0.0040wt%, 실리콘(Si) 0.01~0.5wt%, 인(P) 0.05wt% 이하, 황(S) 0.05wt% 이하, 알루미늄(Sol.Al) 0.03wt% 이하, 나머지 철의 합금조성을 가지는 강에 니켈(Ni) 0.01~2wt%, 니오븀(Nb) 0.01~0.10wt%, 구리(Cu) 0.01~1wt% 중 1종 또는 2종 이상이 기본조성으로 함유되며, 몰리브덴(Mo)이 실리콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 첨가된다. According to a feature of the present invention for achieving the above object, the present invention is carbon (C) 0.19 ~ 0.40wt%, manganese (Mn) 0.5 ~ 2.5wt%, chromium (Cr) 0.1 ~ 0.5wt%, boron (B ) 0.0015 ~ 0.0040wt%, silicon (Si) 0.01 ~ 0.5wt%, phosphorus (P) 0.05wt% or less, sulfur (S) 0.05wt% or less, aluminum (Sol.Al) 0.03wt% or less, alloy of remaining iron One or two or more of 0.01-2 wt% of nickel (Ni), 0.01-10.1 wt% of niobium (Nb), and 0.01-1 wt% of copper (Cu) are contained in the steel having a composition, and molybdenum (Mo) Depending on the content of silicon (Si) is added in the range of 0.05 ~ 0.20wt%.

탄소(C) 0.19~0.40wt%, 망간(Mn) 0.5~2.5wt%, 크롬(Cr) 0.1~0.5wt%, 보론(B) 0.0015~0.0040wt%, 실리콘(Si) 0.01~0.5wt%, 인(P) 0.05wt% 이하, 황(S) 0.05wt% 이하, 알루미늄(Sol.Al) 0.03wt% 이하, 나머지 철의 합금조성을 가지는 강에 니켈(Ni) 0.01~2wt%, 니오븀(Nb) 0.01~0.10wt%, 구리(Cu) 0.01~1wt% 중 1종 또는 2종 이상이 기본조성으로 함유되며, 몰리브덴(Mo)이 실리콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 첨가되는 강판을 가열로에서 오스테나이트 재결정 온도 이상인 900~1000℃로 가열한 후 프레스 가공을 통하여 Ms 온도 이하인 150℃까지 평균 냉각속도 50~150℃로 냉각한다. Carbon (C) 0.19 ~ 0.40wt%, Manganese (Mn) 0.5 ~ 2.5wt%, Chromium (Cr) 0.1 ~ 0.5wt%, Boron (B) 0.0015 ~ 0.0040wt%, Silicon (Si) 0.01 ~ 0.5wt%, 0.05 wt% or less of phosphorus (P), 0.05 wt% or less of sulfur (S), 0.03 wt% or less of aluminum, 0.01 to 2 wt% of nickel (Ni), and niobium (Nb) in steel having an alloy composition of the remaining iron 0.01 ~ 0.10wt%, one or two or more of the copper (Cu) 0.01 ~ 1wt% is contained as a basic composition, molybdenum (Mo) is added in the range of 0.05 ~ 0.20wt% depending on the content of silicon (Si) The steel sheet is heated to 900 ~ 1000 ℃ above the austenite recrystallization temperature in a heating furnace and then cooled to an average cooling rate of 50 ~ 150 ℃ to 150 ℃ below the Ms temperature through a press working.

본 발명의 열처리 경화형 강판은 강도향상을 위해 실리콘(Si), 망간(Mn), 인(P) 등의 도금성 저해원소를 포함하되, 실리콘(Si), 망간(Mn), 인(P)의 첨가에 의해 발생되는 도금성 저하는 몰리브덴(Mo)을 첨가를 통해 향상되도록 한다. The heat-treated hardened steel sheet of the present invention includes a plating inhibitory element such as silicon (Si), manganese (Mn), phosphorus (P), and the like to improve the strength of silicon (Si), manganese (Mn), phosphorus (P) The plating deterioration caused by the addition allows the molybdenum (Mo) to be improved through the addition.

따라서, 1200~1500MPa의 인장강도를 가지면서 도금부착성이 우수한 열처리 경화형 강판을 제조할 수 있다. 즉, 본 발명의 합금설계는 고강도와 더불어 우수한 도금특성이 확보되므로 소비자의 욕구를 반영한 우수한 품질의 자동차용 강판을 제공할 수 있는 유용한 효과가 있다. Therefore, it is possible to manufacture a heat-treated hardened steel sheet having excellent plating adhesion while having a tensile strength of 1200 ~ 1500MPa. That is, the alloy design of the present invention has a useful effect that can provide a high-quality automotive steel sheet reflecting the needs of consumers because the high plating and excellent plating properties are secured.

이하 본 발명에 의한 도금 젖음성이 우수한 열처리 경화형 강판 및 그 제조방법의 바람직한 실시예를 상세하게 설명한다.Hereinafter, the preferred embodiment of the heat-treated hardened steel sheet excellent in plating wettability according to the present invention and a manufacturing method thereof will be described in detail.

본 발명은 탄소(C) 0.19~0.40wt%, 망간(Mn) 0.5~2.5wt%, 크롬(Cr) 0.1~0.5wt%, 보론(B) 0.0015~0.0040wt%, 실리콘(Si) 0.01~0.5wt%, 인(P) 0.05wt% 이하, 황(S) 0.05wt% 이하, 알루미늄(Sol.Al) 0.03wt% 이하, 나머지 철의 합금조성을 가지는 강에 니켈(Ni), 니오븀(Nb), 구리(Cu) 중 1종 또는 2종 이상이 기본조성으로 함유되며, 몰리브덴(Mo)이 실리콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 첨가된다. The present invention is carbon (C) 0.19 ~ 0.40wt%, manganese (Mn) 0.5 ~ 2.5wt%, chromium (Cr) 0.1 ~ 0.5wt%, boron (B) 0.0015 ~ 0.0040wt%, silicon (Si) 0.01 ~ 0.5 wt%, phosphorus (P) 0.05 wt% or less, sulfur (S) 0.05 wt% or less, aluminum (Sol.Al) 0.03 wt% or less, steel (Ni), niobium (Nb), One or two or more of copper (Cu) is contained as a basic composition, molybdenum (Mo) is added in the range of 0.05 ~ 0.20wt% depending on the content of silicon (Si).

보다 상세하게는 몰리브덴(Mo)을 실시콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 함유하고, 탄소(C), 망간(Mn), 크롬(Cr), 보론(B), 실리콘(Si)을 기본으로 한 강재를 성형 후 오스테나이트 재결정 온도 이상인 950℃ 정도의 고온으로 가열하여 완전 오스테나이트화시킨 다음, 이 강판을 프레스 금형에서 한 번에 제품 형상으로 프레스 성형하면서 Ms점 온도 이하인 150℃까지 평균 냉각속도가 50~150℃/s로 냉각하여 제조한다. More specifically, molybdenum (Mo) is contained in the range of 0.05 to 0.20 wt% according to the content of the conducting cone (Si), and carbon (C), manganese (Mn), chromium (Cr), boron (B), and silicon ( After forming the steel based on Si), it is heated to a high temperature of about 950 ° C., which is higher than or equal to the austenite recrystallization temperature, to be completely austenitized. It is prepared by cooling the average cooling rate to 50 ~ 150 ℃ / s to ℃.

본 발명은 강도확보를 위해 실리콘(Si), 망간(Mn), 인(P) 등의 도금성 저해원소를 포함하되, 실리콘(Si), 망간(Mn), 인(P)의 첨가에 의해 발생되는 도금성 저하는 몰리브덴(Mo)을 첨가를 통해 향상되도록 한다. The present invention includes a plating inhibitory element such as silicon (Si), manganese (Mn), phosphorus (P) to secure the strength, but is generated by the addition of silicon (Si), manganese (Mn), phosphorus (P) Degradation of the plating is to be improved through the addition of molybdenum (Mo).

몰리브덴(Mo)은 고용상태로 존재시 결정립계의 결합력을 증가시켜 인(P)에 의한 결정립계 파괴를 개선하고, 실리콘(Si), 망간(Mn)의 표면 농화를 방지한다. Molybdenum (Mo) increases the binding force of the grain boundary when present in solid solution to improve the grain boundary breakdown by phosphorus (P), and prevent the surface thickening of silicon (Si), manganese (Mn).

니켈(Ni)은 0.01~2wt%, 니오븀(Nb)은 0.01~0.10wt%, 구리(Cu)는 0.01~1wt% 범위로 1종 또는 2종 이상이 함유된다. 이들 원소들은 강판의 담금질성을 높이고 담금질 후 강도의 안정화를 높이기 위해 함유된다. Nickel (Ni) is 0.01 to 2wt%, niobium (Nb) is 0.01 to 0.10wt%, copper (Cu) is contained in one or two or more types in the range of 0.01 to 1wt%. These elements are contained to increase the hardenability of the steel sheet and to stabilize the strength after the hardening.

이하, 본 발명의 합금원소들의 기능과 함유량은 다음과 같다. Hereinafter, the function and content of the alloying elements of the present invention are as follows.

탄소(C) 0.19~0.40wt%Carbon (C) 0.19 ~ 0.40wt%

탄소는 강판에 고강도를 부여하기 위한 불가결한 원소로서, 강판의 담금질성을 높이고 담금질 후 강도를 결정하는 주요 원소이다. 탄소는 오스테나이트를 안정화시켜 Ac3점을 내림으로써 담금질 처리 온도의 저온화를 촉진한다. Carbon is an indispensable element for imparting high strength to the steel sheet, and is a major element for increasing the hardenability of the steel sheet and determining the strength after the hardening. Carbon stabilizes austenite and lowers the Ac 3 point to promote lowering of the quenching treatment temperature.

탄소는 소량 첨가시 강도가 낮을 뿐 아니라 오스테나이트가 페라이트로 변태되어 마르텐사이트 분율 확보가 어렵기 때문에 소재의 강도를 확보하기 위해 0.19wt% 이상 첨가한다. 단 0.40wt%를 초과하면 담금질부의 인성열화가 현저해지므로, 그 상한치를 0.40wt%로 제한한다. Carbon is not only low in strength when added in small amounts, but austenitic is transformed into ferrite, so martensite fraction is difficult to secure, so 0.19 wt% or more is added to secure the strength of the material. However, if it exceeds 0.40 wt%, the toughness of the hardened portion becomes remarkable, so the upper limit thereof is limited to 0.40 wt%.

크롬(Cr) 0.1~0.5wt%Chromium (Cr) 0.1-0.5wt%

크롬은 강판의 담금질성을 높이고, 담금질 후 강도를 안정적으로 확보하는데 효과적인 원소이다. 이러한 크롬은 0.1wt% 이상 첨가되어야 강도를 확보할 수 있으며, 0.5wt%를 초과하는 경우에는 그 효과가 증대되지 않는다. 따라서 0.1~0.5wt% 범위로 첨가한다. Chromium is an effective element to increase the hardenability of the steel sheet and to secure the strength after the hardening. Such chromium may be added at least 0.1 wt% to secure strength, and when it exceeds 0.5 wt%, the effect is not increased. Therefore, it is added in the range of 0.1 ~ 0.5wt%.

보론(B) 0.0015~0.0040wt%Boron (B) 0.0015 ~ 0.0040wt%

보론은 연속냉각 변태시 오스테나이트의 페라이트로 변태를 지연시킴으로써 강판의 담금질성을 높이고, 담금질 후 강도를 안정적으로 확보한다. 보론은 0.0015wt% 미만으로 첨가되면 그 효과가 없고, 0.0040wt%를 초과하여 첨가되면 그 효과가 포화된다. 따라서 0.0015~0.0040wt% 범위로 첨가한다.Boron increases the hardenability of the steel sheet by delaying the transformation into austenite ferrite during continuous cooling transformation, and secures the strength after quenching. Boron has no effect when added below 0.0015 wt%, and the effect is saturated when added above 0.0040 wt%. Therefore, it is added in the range 0.0015 ~ 0.0040wt%.

실리콘(Si) 0.01~0.5wt% Silicon (Si) 0.01 ~ 0.5wt%

실리콘은 강판의 담금질성을 높이고 담금질 후 강도의 안정화를 높이는 효과를 갖는다. 하지만 실리콘은 0.01wt% 이상은 첨가되어야 효과가 있으며, 과다 첨가 시 도금성 및 적스케일로 인한 표면 결함을 발생시키고 도금부착성을 저하시켜 미도금 및 도금 박리현상 등의 문제를 발생시키므로 그 상한치를 0.5wt%로 제한한다. Silicon has the effect of increasing the hardenability of the steel sheet and stabilization of strength after quenching. However, silicon is effective only when 0.01wt% or more is added, and when it is added excessively, it causes surface defects due to plating property and red scale, and deteriorates plating adhesion, causing problems such as unplating and plating peeling phenomenon. Limit to 0.5wt%.

인(P) 0.05wt% 이하Phosphorus (P) 0.05wt% or less

인는 강도확보에 유용한 원소이다. 그러나 다량으로 첨가하면 가공성을 저하할 뿐 아니라 용접성도 저하하므로 그 상한치를 0.05wt%로 제한한다.Phosphorus is a useful element for securing strength. However, if a large amount is added, not only the workability is reduced but also the weldability is limited, so the upper limit thereof is limited to 0.05 wt%.

황(S) 0.05wt% 이하Sulfur (S) 0.05 wt% or less

황은 강의 제조시 불가피하게 함유되는 원소로 강판의 강도확보에 기여한다. 황은 과다 첨가시 조대한 개재물을 증가시켜 피로특성을 열화하므로 0.05wt% 이하의 범위로 규제한다. Sulfur is an inevitable element in the production of steel and contributes to securing the strength of the steel sheet. Sulfur deteriorates fatigue characteristics by increasing coarse inclusions when added excessively, so it is regulated in the range of 0.05wt% or less.

알루미늄(Sol.Al) 0.03wt% 이하Aluminum (Sol.Al) 0.03wt% or less

알루미늄은 주로 탈산제로 사용되는 원소이다. 알루미늄은 실리콘과 마찬가지로 강판의 담금질성을 높이고 담금질 후의 강도의 안정화를 높이는 효과를 갖는다. 하지만 알루미늄은 0.03wt%를 초과하여 첨가되면 강도가 저하된다. Aluminum is an element mainly used as a deoxidizer. Aluminum, like silicon, has the effect of increasing the hardenability of the steel sheet and stabilizing the strength after the hardening. However, when aluminum is added in excess of 0.03wt%, the strength is lowered.

니켈(Ni) 0.01~2wt% 이하, 니오븀(Nb) 0.01~0.10wt% 이하, 구리(Cu) 0.01~1wt% 이하의 1종 또는 2종 이상Nickel (Ni) 0.01 to 2 wt% or less, Niobium (Nb) 0.01 to 0.10 wt% or less, copper (Cu) 0.01 to 1 wt% or less

이들 원소들은 강판의 담금질성을 높이고 담금질 후 강도의 안정화를 높이는 효과를 갖는다. 그러나 이들의 함유량이 각각의 상한을 넘으면 그 효과는 포화한다. These elements have the effect of increasing the hardenability of the steel sheet and stabilizing the strength after quenching. However, when these contents exceed each upper limit, the effect will be saturated.

몰리브덴(Mo) 0.05~0.20wt%Molybdenum (Mo) 0.05 ~ 0.20wt%

몰리브덴은 도금부착성을 높이는 효과를 갖는다. 도금부착성을 저해하는 실리콘이 0.1wt% 이상 함유되는 열처리 경화형 강판의 경우 도금부착성을 향상시킨다. 몰리브덴은 0.05wt% 미만 첨가로는 도금부착성 향상 효과가 없고, 0.20wt%를 초과하면 그 효과가 포화한다. Molybdenum has the effect of improving plating adhesion. In the case of a heat-curing steel sheet containing 0.1 wt% or more of silicon that inhibits the plating adhesion, the plating adhesion is improved. Molybdenum has no effect of improving the adhesion to plating by addition of less than 0.05 wt%, and the effect is saturated when it exceeds 0.20 wt%.

본 발명은 상기 강판의 성분들을 함유하고, 나머지는 실질적으로 철(Fe) 및 불가피한 원소들이며, 원료, 자재, 제조설비 등의 상황에 따라 함유되는 원소로서 0.01%이하의 불가피한 불순물의 미세한 혼입도 허용된다. The present invention contains the components of the steel sheet, and the rest are substantially iron (Fe) and unavoidable elements, and the element is included according to the situation of raw materials, materials, manufacturing facilities, etc., allowing fine incorporation of inevitable impurities of less than 0.01%. do.

본 발명에서 사용하는 강판은 열간 프레스 성형에 앞서 가열시에 오스테나이트 온도역으로 가열하여 오스테나이트 변태를 시키므로, 가열 전의 실온에서의 기계적 성질은 중요하지 않다. The steel sheet used in the present invention is heated to an austenite temperature range at the time of heating prior to hot press molding to cause austenite transformation, so the mechanical properties at room temperature before heating are not important.

가열 전의 금속 조직은 특별히 제한되지 않으나, 소지 강판으로서는 열연 강판, 냉연 강판, 도금 강판 중 어느 것을 사용해도 되고, 그 제조 방법은 특별히 한정은 하지 않는다. 도금강판으로는 알루미늄계 도금강판과 아연계 도금강판 또는 전기도금 강판, 용융도금 강판, 합금화 용융 아연도금 강판이 사용될 수 있다. The metal structure before heating is not particularly limited, but any of hot rolled steel sheet, cold rolled steel sheet and plated steel sheet may be used as the base steel sheet, and the production method is not particularly limited. As the plated steel sheet, an aluminum-based plated steel sheet and a zinc-based plated steel sheet or an electroplated steel sheet, a hot dip plated steel sheet, or an alloyed hot dip galvanized steel sheet may be used.

열간 프레스 성형의 조건은 다음과 같다. The conditions of hot press molding are as follows.

상술한 열연강판, 냉연강판, 도금강판을 가열로에서 오스테나이트 재결정 온도 이상인 900~1000℃에서 가열한 후 프레스 가공을 통하여 Ms 온도 이하인 150℃까지 평균 냉각속도 50~150℃로 냉각하여 담금질 처리를 실시한다. The hot rolled steel sheet, cold rolled steel sheet, and plated steel sheet are heated in a heating furnace at 900 to 1000 ° C., which is higher than the austenite recrystallization temperature, and then cooled by pressing to an average cooling rate of 50 ° C. to 150 ° C., which is lower than the Ms temperature. Conduct.

열간 프레스 성형은 오스테나이트 상에서 이루어져야 강도상승 효과가 좋다.따라서 가열온도가 900℃ 보다 낮으면 다른 상들이 생성되어 강도향상 효과가 낮아진다. 그리고 가열온도가 1000℃보다 높으면 산세문제 및 가공성의 열화문제가 발생한다. Hot press molding must be done on the austenite phase to increase the strength. Therefore, when the heating temperature is lower than 900 ° C, other phases are generated and the effect of increasing the strength is lowered. If the heating temperature is higher than 1000 ° C., pickling problems and workability deterioration problems occur.

냉각속도는 열처리 경화형 강판의 안정된 강도 및 인성을 확보하는데 중요하다. 50~150℃의 냉각속도로 냉각하는 경우 강도의 편차가 적고 인성이 뛰어난 마르텐사이트 조직이 얻어진다. 이에 따라 1200~1500MPa의 인장강도와 우수한 도금성이 확보된다.Cooling rate is important to ensure stable strength and toughness of the heat-treated hardened steel sheet. When cooled at a cooling rate of 50-150 ° C., a martensitic structure is obtained which has a small variation in strength and excellent toughness. This ensures a tensile strength of 1200-1500 MPa and excellent plating properties.

이하, 상술한 도금 부착성이 우수한 열처리 경화형 강판 및 그 제조방법을 실시예를 통해 설명하기로 한다. Hereinafter, the heat treatment hardened steel sheet and the method of manufacturing the same having excellent plating adhesion will be described through examples.

도 1은 몰리브덴을 첨가한 열처리 경화형 강판과 몰리브덴을 첨가하지 않고 실리콘만 첨가한 열처리 경화형 강판의 도금부착량 및 파우더링 지수를 나타낸 그래프이고, 도 2는 몰리브덴을 첨가한 열처리 경화형 강판과 몰리브덴을 첨가하지 않고 실리콘만 첨가한 열처리 경화형 강판의 미도금 영역을 나타낸 그래프이다. 1 is a graph showing the coating amount and powdering index of the heat-treated hardened steel sheet added with molybdenum and silicon-free heat-treated hardened steel sheet without adding molybdenum, and FIG. It is a graph which shows the unplated area | region of the heat-hardening type steel plate which only silicon was added without.

[실시예]EXAMPLE

실리콘이 첨가되되, 몰리브덴을 첨가한 강과 그렇지 않은 강을 가열로에서 오스테나이트 재결정 온도 이상인 950℃에서 가열한 후, 프레스 가공을 실시하여 Ms점 온도 이하인 150℃까지 50℃의 냉각속도로 냉각하여 도금부착성 및 파우더링 지수 등을 측정하였다. Silicon is added but molybdenum and other steels are heated in a heating furnace at 950 ° C. above austenite recrystallization temperature, and then press-processed to cool to 150 ° C. below Ms point temperature and plated by cooling at 50 ° C. Adhesion and powdering index were measured.

도 1 및 도 2 도시된 바와 같이, 실리콘이 첨가되는 강에서 몰리브덴을 첨가하는 경우 도금부착성이 향상되고, 미도금(bare-spot) 영역도 현저하게 감소되었다. 그리고, 도금 부착성에 악영향을 미치는 파우더링 지수(Powdering Index)도 현저하게 낮아졌다. 1 and 2, when molybdenum is added in the steel to which silicon is added, the plating adhesion is improved, and the bare-spot area is also significantly reduced. In addition, the Powdering Index, which adversely affects the plating adhesion, was also significantly lowered.

도 1과 도 2의 결과를 통해서, 강도 확보를 위해 실리콘이 첨가되는 강에서 적정 몰리브덴을 함유하는 경우 도금부착성이 향상됨을 알 수 있다. 1 and 2, it can be seen that the plating adhesion is improved when the molybdenum is contained in the steel to which silicon is added to secure the strength.

이와 같은 본 발명의 기본적인 기술적 사상의 범주 내에서, 당업계의 통상의 지식을 가진 자에게 있어서는 다른 많은 변형이 가능함은 물론이고, 본 발명의 권리범위는 첨부한 특허청구 범위에 기초하여 해석되어야 할 것이다.  Within the scope of the basic technical idea of the present invention, many other modifications are possible to those skilled in the art, and the scope of the present invention should be interpreted based on the appended claims. will be.

도 1은 몰리브덴을 첨가한 열처리 경화형 강판과 몰리브덴을 첨가하지 않고 실리콘만 첨가한 열처리 경화형 강판의 도금부착량 및 파우더링 지수를 나타낸 그래프.1 is a graph showing the coating amount and the powdering index of the heat-treated hardened steel sheet added with molybdenum and silicon-treated heat-treated hardened steel sheet without adding molybdenum.

도 2는 몰리브덴을 첨가한 열처리 경화형 강판과 몰리브덴을 첨가하지 않고 실리콘만 첨가한 열처리 경화형 강판의 미도금 영역을 나타낸 그래프.2 is a graph showing an unplated region of a heat-treated hardened steel sheet added with molybdenum and silicon-treated heat-treated hardened steel sheet without adding molybdenum.

Claims (2)

탄소(C) 0.19~0.40wt%, 망간(Mn) 0.5~2.5wt%, 크롬(Cr) 0.1~0.5wt%, 보론(B) 0.0015~0.0040wt%, 실리콘(Si) 0.01~0.5wt%, 인(P) 0.05wt% 이하, 황(S) 0.05wt% 이하, 알루미늄(Sol.Al) 0.03wt% 이하, 나머지 철의 합금조성을 가지는 강에 니켈(Ni) 0.01~2wt%, 니오븀(Nb) 0.01~0.10wt%, 구리(Cu) 0.01~1wt% 중 1종 또는 2종 이상이 기본조성으로 함유되며, 몰리브덴(Mo)이 실리콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 첨가되는 것을 특징으로 하는 도금 젖음성이 우수한 열처리 경화형 강판. Carbon (C) 0.19 ~ 0.40wt%, Manganese (Mn) 0.5 ~ 2.5wt%, Chromium (Cr) 0.1 ~ 0.5wt%, Boron (B) 0.0015 ~ 0.0040wt%, Silicon (Si) 0.01 ~ 0.5wt%, 0.05 wt% or less of phosphorus (P), 0.05 wt% or less of sulfur (S), 0.03 wt% or less of aluminum, 0.01 to 2 wt% of nickel (Ni), and niobium (Nb) in steel having an alloy composition of the remaining iron 0.01 ~ 0.10wt%, one or two or more of the copper (Cu) 0.01 ~ 1wt% is contained as a basic composition, molybdenum (Mo) is added in the range of 0.05 ~ 0.20wt% depending on the content of silicon (Si) Heat-treated hardened steel sheet excellent in plating wettability, characterized in that. 탄소(C) 0.19~0.40wt%, 망간(Mn) 0.5~2.5wt%, 크롬(Cr) 0.1~0.5wt%, 보론(B) 0.0015~0.0040wt%, 실리콘(Si) 0.01~0.5wt%, 인(P) 0.05wt% 이하, 황(S) 0.05wt% 이하, 알루미늄(Sol.Al) 0.03wt% 이하, 나머지 철의 합금조성을 가지는 강에 니켈(Ni) 0.01~2wt%, 니오븀(Nb) 0.01~0.10wt%, 구리(Cu) 0.01~1wt% 중 1종 또는 2종 이상이 기본조성으로 함유되며, 몰리브덴(Mo)이 실리콘(Si)의 함량에 따라 0.05~0.20wt% 범위로 첨가되는 강판을 Carbon (C) 0.19 ~ 0.40wt%, Manganese (Mn) 0.5 ~ 2.5wt%, Chromium (Cr) 0.1 ~ 0.5wt%, Boron (B) 0.0015 ~ 0.0040wt%, Silicon (Si) 0.01 ~ 0.5wt%, 0.05 wt% or less of phosphorus (P), 0.05 wt% or less of sulfur (S), 0.03 wt% or less of aluminum, 0.01 to 2 wt% of nickel (Ni), and niobium (Nb) in steel having an alloy composition of the remaining iron 0.01 ~ 0.10wt%, one or two or more of the copper (Cu) 0.01 ~ 1wt% is contained as a basic composition, molybdenum (Mo) is added in the range of 0.05 ~ 0.20wt% depending on the content of silicon (Si) Grater 가열로에서 오스테나이트 재결정 온도 이상인 900~1000℃로 가열한 후 프레스 가공을 통하여 Ms 온도 이하인 150℃까지 평균 냉각속도 50~150℃로 냉각하는 것을 특징으로 하는 도금 젖음성이 우수한 열처리 경화형 강판의 제조방법. Method for producing a heat-treated hardened steel sheet having excellent plating wettability, characterized in that the heating is heated to 900 ~ 1000 ℃ above the austenite recrystallization temperature and then cooled to 150 ℃ below the Ms temperature through the press working process at an average cooling rate of 50 ~ 150 ℃ .
KR1020080106090A 2008-10-28 2008-10-28 Quenched hot-rolled steel sheet with excellent coating adhesion, and method for producing the same KR20100047018A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10655204B2 (en) 2015-05-26 2020-05-19 Posco Hot press formed article having good anti-delamination, and preparation method for same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10655204B2 (en) 2015-05-26 2020-05-19 Posco Hot press formed article having good anti-delamination, and preparation method for same

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