KR100370582B1 - Manufacturing method of hot rolled hot dip galvanized steel sheet with excellent workability - Google Patents
Manufacturing method of hot rolled hot dip galvanized steel sheet with excellent workability Download PDFInfo
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- KR100370582B1 KR100370582B1 KR10-1998-0062068A KR19980062068A KR100370582B1 KR 100370582 B1 KR100370582 B1 KR 100370582B1 KR 19980062068 A KR19980062068 A KR 19980062068A KR 100370582 B1 KR100370582 B1 KR 100370582B1
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- 238000004519 manufacturing process Methods 0.000 title abstract description 21
- 229910001335 Galvanized steel Inorganic materials 0.000 title description 17
- 239000008397 galvanized steel Substances 0.000 title description 17
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 79
- 239000010959 steel Substances 0.000 claims abstract description 79
- 238000007747 plating Methods 0.000 claims abstract description 61
- 238000010438 heat treatment Methods 0.000 claims abstract description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 14
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910000423 chromium oxide Inorganic materials 0.000 claims abstract description 10
- 239000011701 zinc Substances 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000011651 chromium Substances 0.000 claims description 20
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 13
- 238000000034 method Methods 0.000 abstract description 13
- 229910052742 iron Inorganic materials 0.000 abstract description 7
- 230000008569 process Effects 0.000 abstract description 7
- 238000005097 cold rolling Methods 0.000 abstract description 3
- 230000008859 change Effects 0.000 abstract description 2
- 238000004904 shortening Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 18
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 11
- 238000012545 processing Methods 0.000 description 11
- 238000005098 hot rolling Methods 0.000 description 9
- 230000009466 transformation Effects 0.000 description 9
- 239000006104 solid solution Substances 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005246 galvanizing Methods 0.000 description 5
- 230000007704 transition Effects 0.000 description 5
- 238000005297 material degradation process Methods 0.000 description 4
- 238000005554 pickling Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000010960 cold rolled steel Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 230000008719 thickening Effects 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910015372 FeAl Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000003287 bathing Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910003470 tongbaite Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/002—Pretreatement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B1/00—Cleaning by methods involving the use of tools, brushes, or analogous members
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
Abstract
본 발명은 고가공성이 요구되는 전기스위치 박스 등에 사용되는 열연 용융아연 도금강판(Hot-rolled Galvanized Iron : 이하, HGI라 칭함)을 제조하는 방법에 관한 것으로, 강중 Cr이 0.3∼0.5중량%, B:0.010∼0.030중량%를 함유한 Ti첨가 극저탄소 열연강판을 산세하고, 브러쉬롤을 사용하여 잔존하는 크롬산화층을 제거후, 강판온도를 460∼500℃로하여 도금전 열처리를 실시하고, A1:0.15∼0.20중량%, 나머지는 Zn와 불가피한 불순물로 이루어진 아연도금욕에 침적하여 도금하는 것을 특징으로 한다.The present invention relates to a method for manufacturing a hot-rolled galvanized iron sheet (hereinafter referred to as HGI) used in an electric switch box or the like requiring high workability. : Pickled Ti-added ultra low carbon hot rolled steel sheet containing 0.010 to 0.030% by weight, using a brush roll to remove the remaining chromium oxide layer, and then performing a heat treatment before plating at a steel sheet temperature of 460 to 500 ° C., A1: 0.15 to 0.20% by weight, the remainder is characterized by immersing and plating in a zinc plating bath composed of Zn and inevitable impurities.
본 발명에 의하면, 종래 실시하던 냉간압연 공정의 단축에 따른 제조비용 및 성에너지 절감의 이점이 있으며, 도금전 열처리에 따른 재질변화를 최소화할 수 있어서 우수한 가공성을 확보할 수 있고, 도금전처리 조건을 변경하여 도금밀착성을 확보함으로써 결과적으로 경제성 및 품질을 향상시켜 산업상 이용가치가 매우 크다.According to the present invention, there is an advantage of reducing the manufacturing cost and sex energy due to the shortening of the conventional cold rolling process, it is possible to minimize the change in the material due to the heat treatment before plating to ensure excellent processability, pre-plating conditions By changing the plating adhesion to improve the economical and quality as a result, the industrial use value is very large.
Description
본 발명은 고가공성이 요구되는 전기스위치 박스 등에 사용되는 열연 용융아연 도금강판(Hot-rolled Galvanized Iron : 이하, HGI라 칭함)을 제조하는 방법에 관한 것으로, 보다 상세하게는 Cr 단독첨가 극저탄소강의 용융도금시 발생하는 재질열화, 내2차 충격성 저하 및 도금밀착성 저하를 방지한 가공성 및 도금밀착성이 우수한 열연 용융아연 도금 강판을 제조하는 방법에 관한 것이다.The present invention relates to a method for manufacturing a hot-rolled galvanized iron sheet (hereinafter referred to as HGI) used in an electric switch box or the like requiring high processability, and more specifically, Cr-added ultra low carbon steel. The present invention relates to a method for manufacturing a hot-rolled hot-dip galvanized steel sheet excellent in workability and plating adhesion, which prevents material degradation, secondary impact resistance, and plating adhesion from occurring during hot dip plating.
최근 용융아연 도금강판의 사용분야가 확대되어, 예전에는 후물재 구조물의 경우 열연강판을 산세후 도장만을 실시하여 사용하였으나, 열연강판의 내식성 향상요구에 따라 열연용융아연 도금강판 제품이 개발되어 생산되고 있다.Recently, the field of use of hot-dip galvanized steel sheet has been expanded, and in the past, in the case of thick material structure, hot-rolled steel sheet was used after the pickling and coating. have.
더욱이, 최근에는 열연 용융아연 도금강판의 주요 용도인 건축용 파이프, 가드레일, 데크플레이트(deck plate) 등의 구조물 외에 수요가의 요구에 따라 심가공을 필요로 하는 스위치박스 등에 사용할 수 있는 가공성이 매우 우수한 열연 용융아연 도금강판 제품의 개발 필요성이 절실해졌다.Moreover, in recent years, in addition to structures such as construction pipes, guard rails, deck plates, etc., which are major applications of hot-rolled hot-dip galvanized steel sheets, workability can be used for switch boxes requiring deep processing according to demand. There is an urgent need to develop an excellent hot rolled hot dip galvanized steel sheet product.
지금까지 스위치박스용 용융아연 도금강판을 제조하는 종래의 방법으로는 극저탄소강을 베이스로하여 탄질화물 형성원소인 Ti를 첨가한 초심가공용(Extra Deep Drawing Quality:이하, EDDQ라 칭함) 냉연강판을 연속 용융도금 설비(Continuous Galvanizing Line:이하, CGL이라 칭함)에서 780∼820℃로 연속소둔한후 용융도금을 실시하여 제조하고 있다.Until now, the conventional method of manufacturing hot-dip galvanized steel sheet for switch box is based on ultra-low carbon steel, and used for super deep processing (Extra Deep Drawing Quality: hereinafter referred to as EDDQ) containing Ti, a carbon nitride forming element. It is manufactured by continuous annealing at 780 ~ 820 ℃ in continuous galvanizing line (hereinafter referred to as CGL).
그러나 최근 냉간압연 공정 단축에 따른 제조비용의 절감목적으로 열연강판을 도금 소재로 하여 냉연강판의 EDDQ와 동등한 고가공성을 요구하는 경우가 많다.However, in recent years, in order to reduce manufacturing costs due to the shortening of the cold rolling process, hot rolled steel sheet is used as a plating material and often requires high processability equivalent to EDDQ of cold rolled steel sheet.
한편, 두께 2.5mm이상의 후물재 열연강판의 경우 고연성을 확보하기 위하여 극저탄소강(C≤0.002중량%)을 이용한 대표적인 사례로, 일본 고베제강(KSC)에서는, 0.002중량% C-0.03중량% Ti강을 Ar3이상의 온도에서 압연후 600℃ 이하 온도에서 권취함으로써 인장강도 28∼29㎏/㎟, 연신율 55% 이상인 가공용 열연강판을 제조하는 기술을 개발한 바 있다. 이 기술에서 저온권취를 선택한 가장 큰 이유는 강중에 고용 C를 적정히 잔존시켜 입계강도를 상승시킴으로써 내2차 가공취성을 개선하기 위한 것으로 알려져 있다.Meanwhile, in the case of thick hot rolled steel sheets having a thickness of 2.5 mm or more, a typical example of using ultra-low carbon steel (C≤0.002 wt%) to secure high ductility, in Japan Kobe Steel (KSC), 0.002 wt% C-0.03 wt% After rolling Ti steel at a temperature of Ar 3 or higher and winding it at a temperature of 600 ° C. or lower, a technology for manufacturing a hot rolled steel sheet for processing having a tensile strength of 28 to 29 kg / mm 2 and an elongation of 55% or more has been developed. The biggest reason for choosing low temperature winding in this technique is known to improve secondary processing brittleness by increasing the grain strength by appropriately remaining solid solution C in the steel.
그리고, 일본 강관(NKK)의 경우 역시 연성을 확보하기 위하여 0.002중량%C에 0.01∼0.02중량%의 Ti 또는 Nb를 단독첨가하고, 650℃ 이상에서 고온권치하여 50∼53% 범위의 연신율을 갖는 가공용 열연강판의 제조기술을 발표한 바 있다.In addition, in the case of Japanese steel pipe (NKK), 0.01-0.02% by weight of Ti or Nb is added alone to 0.002% by weight of C in order to ensure ductility, and it has an elongation in the range of 50-53% by winding at high temperature at 650 ° C or higher. It has announced the manufacturing technology of hot rolled steel sheets for processing.
이와 같이, 재질적으로 유리한 극저탄소강임에도 불구하고 1.6mm두께 이하의 박물인 용융아연 열연강판을 제조하는데 문제가 되는 것은, 열간압연시 Ar3변태점이 높기 때문에 압연온도의 확보가 어렵고, 조직적으로는 미세립과 조대립이 혼재한 혼립조직 등에 기인한 연신율의 열화가 발생하기 때문이다.As such, the problem of producing a hot-dip hot-dip steel sheet of 1.6 mm thickness or less despite being a materially advantageous ultra-low carbon steel is that it is difficult to secure a rolling temperature due to the high Ar 3 transformation point during hot rolling. This is because deterioration of the elongation caused by the mixed structure of the fine grains and coarse grains occurs.
환원하면, 이와 같은 Ti 첨가 극저탄소강을 이용하여 박물 열간 압연강판을 제조하는데 있어서 문제가 되는 것은 열간 압연온도의 저하에 따른 혼립조직의 생성에 의한 재질열화이다.In other words, a problem in producing a thin hot rolled steel sheet using such Ti-added ultra low carbon steel is material deterioration due to formation of a mixed structure due to a decrease in hot rolling temperature.
심가공 냉연강판의 제조에 이용되는 Ti첨가 극저탄소강의 경우 통상 3.5∼4.0mm로 압연되며, 910℃ 이상에서 열간압연을 마무리한다. 그런데 열간압연 두께가 박물화될수록 압연마무리 온도는 저하되어 1.6mm두께 강판의 경우, 통상 열간압연 마무리온도는 860∼880℃ 수준이 된다.In the case of the Ti-added ultra-low carbon steel used for the production of deep-processed cold rolled steel sheets, it is usually rolled to 3.5 to 4.0 mm and finishes hot rolling at 910 ° C or higher. However, as the hot rolling thickness is reduced, the rolling finish temperature is lowered, and in the case of 1.6 mm thick steel sheets, the hot rolling finish temperature is usually 860 to 880 ° C.
따라서 극저탄소강의 경우 열간압연시의 온도 저하에 의한 불균일 조직의 생성이 더욱 조장될 수 있음을 충분히 예상할 수 있어, 결국 기존의 오스테나이트역 압연에 의하여 가공용 박물 열연강판을 제조하기 위해서는 Ar3변태점을 저하시키는 원소의 첨가를 고려할 필요가 있다.Therefore, in the case of ultra low carbon steel, it can be expected that the formation of the non-uniform structure by the temperature decrease during hot rolling can be further promoted. Thus, in order to manufacture the hot-rolled steel sheet for processing by conventional austenite reverse rolling, Ar 3 transformation point It is necessary to consider the addition of an element that lowers the temperature.
그리고, 열연 용융아연 도금강판의 도금 소재로서 연성확보가 재질적으로 유리한 극저탄소강을 체택했음에도 불구하고 약 1.6mm 두께의 박물인 열연 용융아연 도금강판을 제조시 문제가 되는 것은, Ar3변태점(페라이트 변태온도)이 높기 때문에 압연온도의 확보가 어렵고, 조직적으로는 미세립과 조대립이 혼재한 혼립조직 등에 기인한 연신율의 현저한 감소가 발생하여 가공성이 떨어지는 문제점이 있다.In addition, despite the use of ultra-low carbon steel, which is advantageous in material ductility, as a plating material for hot-rolled hot-dip galvanized steel sheet, a problem in manufacturing hot-rolled hot-dip galvanized steel sheet, which is about 1.6 mm thick, is a problem of Ar 3 transformation point Due to the high ferrite transformation temperature, it is difficult to secure the rolling temperature, and a systematic decrease in elongation due to a mixed structure in which fine grains and coarse grains are mixed occurs, resulting in poor workability.
반면 극저탄소강에 Ar3변태점을 저하시키는 Cr을 첨가하면 가공성은 향상되나, 0.5%를 초과시 센지미어(Sendzimir) 혹은 무산화로방식의 CGL에서 열처리시에는 Cr의 표면농화에 따른 안정한 크롬 산화물의 형성으로 용융도금시 미도금이 발생하거나, 가공과정에서 치명적인 도금박리가 발생하는 문제점이 발생한다.On the other hand, the addition of Cr, which reduces the Ar 3 transformation point, to the ultra low carbon steel improves the workability, but when it exceeds 0.5%, the formation of stable chromium oxide due to the surface thickening of Cr during heat treatment in Czi of Sendzimir or non-oxidation furnace method As a result, unplating may occur during melt plating, or a fatal plating peeling may occur during processing.
그리고, 도금전 열처리 온도가 높으면 일부 고용탄소의 재고용에 따른 재질열화가 발생하는 문제점이 나타났다.In addition, when the heat treatment temperature before plating is high, there is a problem in that material degradation occurs due to re-use of some solid solution carbon.
또한, 고가공용 열연강판의 경우 입계 취성파괴에 의해 내2차 가공성이 저하되는 문제점이 나타나므로 이에 대한 개선이 필요하였다.In addition, in the case of the hot rolled steel sheet for high processing, the secondary workability is deteriorated due to the brittle fracture of grain boundary, and thus an improvement is required.
본 발명은 상기와 같은 Cr 단독첨가 극저탄소강의 용융도금시 발생하는 재질열화, 내2차 충격성 저하 및 도금밀착성 저하 등의 문제점을 해결하기 위해 본발명자가 수년에 걸친 연구와 현장 적용 실험을 통해 얻어진 결과에 근거하여 이루어진 것으로, 가공성 및 도금밀착성이 우수한 열연 용융아연 도금강판을 제조하는 방법을 제공함에 그 목적이 있다.The present invention is obtained by the present inventors through years of research and field application experiments to solve the problems such as material degradation, secondary impact resistance degradation and plating adhesion degradation caused during the hot-melting of Cr-added ultra low carbon steel as described above It is made on the basis of the results, and an object thereof is to provide a method for producing a hot-rolled hot-dip galvanized steel sheet excellent in workability and plating adhesion.
상기 목적을 달성하기 위한 본 발명의 가공성이 우수한 용융아연 도금강판의 제조방법은, 중량%로, 강중 Cr이 0.3∼0.5%, B:0.010∼0.030%를 함유한 Ti 첨가 극저탄소 열연강판을 산세하고, 브러쉬롤을 사용하여 잔존하는 스케일 및 크롬산화층을 제거한 후, 도금전 열처리시 강판온도를 460∼500℃로 하고, A1:0.15∼0.20중량% ,나머지는 Zn과 불가피한 불순물로 이루어진 통상의 아연도금욕에 침적하여 도금하는 것을 특징으로 하는 구성이다.Method for producing a hot-dip galvanized steel sheet excellent in workability of the present invention for achieving the above object is pickling Ti-added ultra-low carbon hot rolled steel sheet containing 0.3 to 0.5% Cr in steel, B: 0.010 to 0.030% by weight After removing the remaining scale and the chromium oxide layer using a brush roll, the steel sheet temperature during the heat treatment before plating was set to 460 to 500 ° C, A1: 0.15 to 0.20% by weight, and the rest of the usual zinc composed of Zn and unavoidable impurities. It is the structure characterized by immersing in a plating bath and plating.
이하에서는 양호한 실시예와 관련하여 본 발명을 상세하게 설명한다.Hereinafter, the present invention will be described in detail with reference to the preferred embodiments.
본 발명에 있어서 강중 Cr, B 첨가량 및 도금전 열처리온도를 한정한 이유를 설명하면 다음과 같다.In the present invention, the reason for limiting the amount of Cr and B added in steel and the heat treatment temperature before plating is as follows.
Ar3변태점을 크게 저하시키는 Cr을 0.3∼0.5중량% 범위로 한정하여 첨가하는 것은, 이 범위내로 Cr을 첨가하는 것에 의해 연신율이 개선되나 강도의 상승은 거의 없기 때문이다. 이는 강중 Cr원소의 고용경화능이 적고, 강중 C를 고정하는 효과가 있기 때문이다.The reason why Cr is added to the range of 0.3 to 0.5% by weight that significantly lowers the Ar 3 transformation point is because the elongation is improved by adding Cr within this range, but there is little increase in strength. This is because the solid hardening capacity of the Cr element in the steel is low and the effect of fixing the steel C is strong.
그러나 Cr 함량이 0.3중량% 미만인 경우 C를 고정하는 효과가 미미하고 Ar3변태점의 저하가 20℃ 미만으로 적어서 열간압연시 적정 사상압연온도의 확보가 관란하여 가공성이 불량한 문제점이 발생하였다.However, when the Cr content is less than 0.3% by weight, the C-fixing effect is insignificant, and the drop in Ar 3 transformation point is less than 20 ° C., so that the appropriate finishing rolling temperature during hot rolling is disturbed, resulting in poor workability.
반면, 강중 Cr이 0.5중량%를 초과시는 Ar3변태점 저하 및 C 를 고정하는 효과는 매우 크나, Cr 자체의 고용경화에 따른 가공성의 열화가 나타나고 도금 밀착성도 크게 저하되기 때문이다.On the other hand, when Cr exceeds 0.5 wt% in steel, the effect of lowering the Ar 3 transformation point and fixing C is very high, but deterioration of workability due to solid solution hardening of Cr itself is exhibited, and plating adhesion is also greatly reduced.
B를 0.010∼0.030%로 한정하여 첨가하는 것은 극저탄소강에서 문제가 되는 내2차 가공취성의 저하를 방지하기 위한 것으로, 0.010% 미만에서는 페라이트 결정립의 조대화에 미치는 효과가 미미하며, 0.030%를 초과시는 페라이트로의 변태를 크게 지연시켜 TiC 석출 억제에 따른 고용탄소량 증가로 재질이 크게 열화되기 때문이다.The addition of B in an amount of 0.010 to 0.030% is used to prevent secondary work brittleness, which is a problem in ultra low carbon steel, and less than 0.010% has a negligible effect on the coarsening of ferrite grains. This is because the material is significantly deteriorated due to the increase in the amount of dissolved carbon due to the inhibition of TiC precipitation.
Ti는 강중 잔류 고용탄소를 TiC로 석출하여 도금전 열처리 과정시 탄소의 재고용에 따른 재질열화를 막기 위해 첨가한 것으로, 본 발명의 경우 0.030% 미만에서는 일부 고용탄소에 의한 재질열화가 발생하며, 0.060% 초과시에는 과도한 Ti계 석출물로 인해 강도가 증가하고 연성이 저하되는 문제점이 있으므로 0.030∼0.060%로 첨가하였다.Ti is added to prevent the material deterioration due to the re-use of carbon during the heat treatment process before plating by depositing the residual solid solution carbon in the steel, in the case of the present invention less than 0.030%, material degradation due to some dissolved carbon occurs, 0.060 When it exceeds%, the strength is increased due to excessive Ti precipitates and ductility is deteriorated, so it is added at 0.030 to 0.060%.
기타 강중 원소로서 Mn은 필요한 강도 확보를 위해 대략 0.15중량% 함유하며, C:0.002중량% 이하, P:0.01중량% 이하, S:0.005중량% 이하, 고용 A1:0.03중량%, 고용N는 30ppm 이하로 첨가하였다.As other elements in steel, Mn contains about 0.15% by weight to secure the necessary strength, C: 0.002% by weight, P: 0.01% by weight, S: 0.005% by weight, solid solution A1: 0.03% by weight, and solid solution N is 30 ppm. It added below.
또한, 본 발명에서 도금전 열처리시 가열대에서의 강판온도를 460∼500℃로 한정하는 것은 다음과 같은 이유에 기인한다.In the present invention, the steel sheet temperature at the heating table during the heat treatment before plating is limited to 460 to 500 ° C due to the following reason.
염산산세를 거친 열연강판은 예열대에서 강판온도를 약 150℃로 승온한 후, 간접가열로인 가열대에서 460∼500℃로 가열하고 가스냉각대를 통과하여 약 460℃의 강판 입욕온도로 도금욕에 들어가게 된다.After hot-rolled hydrochloric acid, the hot rolled steel sheet is heated to about 150 ℃ in the preheating zone, then heated to 460 ~ 500 ℃ in the heating zone, which is an indirect heating furnace, and passed through the gas cooling zone to the steel plate bathing temperature of about 460 ℃. Will enter.
이때 10∼20%의 수소분위기의 로내에서 염산산세후 남아있는 강판의 산화피막을 환원 제거하여 도금밀착성을 향상시킨다.At this time, the plating film is improved by reducing and removing the oxide film of the steel sheet remaining after hydrochloric acid washing in the furnace of 10 to 20% hydrogen atmosphere.
한편, 용융아연 열연강판의 기계적성질은 냉연강판을 도금소재로 하는 CGL과 달리 제강성분과 열간압연 공정에서 거의 결정되므로 열연강판을 도금소재로 하는 PGL의 열처리공정에서는 가능한 재질변화를 일으키지 않도록 하여야 한다.On the other hand, the mechanical properties of hot-dip galvanized steel sheets are almost determined in the steelmaking component and hot rolling process, unlike CGL, which uses cold-rolled steel sheet as a plated material. .
환원열처리로내 강판의 온도가 낮은 것이 고용탄소의 재용해에 따른 기계적성질의 열화를 최소화하는 측면에서 유리하지만, 강판온도가 460℃ 미만으로 너무 낮으면 Fe와 Zn합금층 생성이 곤란하여 도금층 박리가 발생할 가능성이 높다. 반면 강판온도가 500℃를 초과시에는 강중 Cr이 표면으로 편석하여 치밀한 크롬산화물을 형성하여 미도금 및 도금 박리가 발생할 가능성이 증가하며, 고용탄소의 재용해에 따른 강도 상승으로 가공성이 크게 열화되는 문제점이 있기 때문이다.Although the low temperature of the steel sheet in the reduction heat treatment furnace is advantageous in minimizing the deterioration of mechanical properties due to the re-dissolution of the solid solution carbon, if the temperature of the steel sheet is lower than 460 ° C, it is difficult to form the Fe and Zn alloy layers and peel the plating layer. Is likely to occur. On the other hand, when the steel plate temperature exceeds 500 ℃, the possibility of unplating and plating peeling is increased due to the formation of dense chromium oxide due to segregation of Cr in the steel, and the workability is greatly deteriorated due to the increase in strength due to the re-dissolution of solid carbon. Because of this.
한편 본 발명의 Cr첨가강에서 Cr은 매우 산화되기 쉽기 때문에 통상의 용융아연 열연강판의 제조공정에서 열간압연과정 및 연속소둔 열처리공정 중에서 강판표면으로 확산되어 이들 원소의 농도가 모재(bulk)보다 10∼100배 정도 높게 된다.On the other hand, in the Cr-added steel of the present invention, since Cr is very easily oxidized, it is diffused to the surface of the steel sheet during the hot rolling process and the continuous annealing heat treatment process in the manufacturing process of ordinary hot-dip galvanized steel sheet, so that the concentration of these elements is 10 It becomes about 100 times higher.
이와 같이 결정입게나 입내에 농화된 난도금성 원소는 로내 분위기중의 극미량 수분이나 불순물과 반응하여 CrO2등의 산화물 피막을 형성하므로 용융아연 도금공정에서 용융아연과의 젖음성(wettability)을 크게 저하시킨다.As such, the non-plating element concentrated in the crystal grains or the mouth reacts with an extremely small amount of moisture or impurities in the furnace atmosphere to form an oxide film such as CrO 2 , which greatly reduces wettability with molten zinc in the hot dip galvanizing process. .
그 결과 젖음성 확보가 곤란하게 되어 미도금현상이 다발하게 되거나, 용융도금이 되더라도 도금밀착성을 열화시켜 가공시 도금박리가 발생하게 된다.As a result, it is difficult to secure the wettability, which leads to unplated phenomena, or even hot-dip plating, which degrades the adhesion of the plating and causes plating peeling during processing.
또한 난도금성 원소의 농화부와 비농화부에서 도금층의 불균일로 인해 용융도금후 합금화처리시 크게 영향을 미치게 되는 문제가 발생하게 된다.In addition, due to the non-uniformity of the plating layer in the thickening and non-concentrating portion of the non-plating element is a problem that greatly affects during the alloying process after hot-dip plating.
이와 같은 문제를 해결하기 위하여 본 발명에서는 2차적으로 브러쉬롤을 사용하여 잔존하는 크롬산화물을 제거함으로써 도금밀착성을 향상시키고자 하였다.In order to solve this problem, in the present invention, by using a brush roll to remove the remaining chromium oxide to improve the plating adhesion.
이때 표면연삭량이 0.5㎛ 미만일 경우, 두껍게 존재하는 크롬산화물을 완전히 제거할 수 없으며, 2㎛를 초과하면 철손실량이 증가하고 도금밀착성의 향상 효과도 포화 상태에 도달한 것으로 나타났다.At this time, if the surface grinding amount is less than 0.5㎛, it is not possible to completely remove the thick chromium oxide, if it exceeds 2㎛ it was found that the iron loss amount is increased and the effect of improving the plated adhesion also reached the saturation state.
따라서 브러쉬롤을 사용하여 짧은 시간 내에 Cr첨가강의 디스케일링이 가능하도록 한 본 발명에 의하면, Cr함량이 0.5% 이하인 열연강판의 용융도금시 표면외관이 우수하고 도금밀착성이 우수한 열연용융아연 도금 강판을 제조할 수 있다.Therefore, according to the present invention, which enables descaling of Cr-added steel in a short time by using a brush roll, a hot-rolled hot-dip galvanized steel sheet having excellent surface appearance and excellent plating adhesion when hot-dip galvanizing a hot-rolled steel sheet having a Cr content of 0.5% or less It can manufacture.
또한, 용융아연 도금욕의 A1첨가량 증가(기존0.18%→0.20% 이상)에 의해서 소지철과 도금층 계면에 Zn-Fe-Al-Cr계 또는 Fe-Al-Cr의 합금층 생성량을 증가시킴으로써 합금원소의 산화층을 환원시키는 것에 의해, 계면에서 합금원소의 산화피막으로 인한 용융도금 젖음성 저하를 방지하는 것을 검토하였다.In addition, by increasing the amount of A1 added in the hot-dip galvanizing bath (from 0.18% to 0.20% or more), alloying elements of Zn-Fe-Al-Cr-based or Fe-Al-Cr are increased at the interface between the base iron and the plating layer. By reducing the oxide layer, the study was conducted to prevent a decrease in the melt plating wettability caused by the oxide film of the alloying element at the interface.
그러나 도금욕내 A1농도가 0.20중량% 초과시는 도금욕에 불가피하게 불순물로 첨가되는 Pb와 공존시 입계부식이 발생하기 쉽기 때문에 경시도금박리가 발생할 가능성이 높다. 또한, 도금욕내 Al 농도 증가는 도금욕내 상부 드로스(Dross) 발생량을 증가시키고 도금층 표면에 부착시 표면외관 결함을 발생시키는 문제점이 있다.However, when the A1 concentration in the plating bath exceeds 0.20% by weight, it is highly likely to cause delamination over time because grain boundary corrosion easily occurs when co-existing with Pb, which is inevitably added to the plating bath. In addition, an increase in Al concentration in the plating bath increases the amount of upper dross generated in the plating bath and causes surface appearance defects when attached to the surface of the plating layer.
한편, Al이 0.15% 미만인 경우는 Fe 와 Zn 사이의 반응의 확산장벽으로 작용하는 FeAl5합금층 생성을억제하여 취약한 합금층을 형성하여 도금층 박리가 발생할 가능성이 증가하는 단점이 있다.On the other hand, if Al is less than 0.15%, the FeAl 5 alloy layer acts as a diffusion barrier between the reaction between Fe and Zn to suppress the formation of a weak alloy layer has a disadvantage that the possibility of plating layer peeling increases.
그리고, Fe, Pb 등의 불가피하게 혼입된 불순물 등은 도금욕 내에서 드로스 발생을 증가시켜 표면품질을 열화시키므로 0.1중량%이하로 관리하는 것이 좋다.In addition, impurities, such as Fe and Pb, are inevitably mixed in the plating bath to increase the dross generation and deteriorate the surface quality, so it is better to manage at 0.1% by weight or less.
이하에서는 실시예와 관련하여 본 발명을 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.
실시예 1Example 1
강중 Cr함량이 상이한 극저탄소 열연강판(0.002%C-0.14%Mn-0.04%Ti-0.006%PUltra-low carbon hot rolled steel sheets with different Cr contents in steel (0.002% C-0.14% Mn-0.04% Ti-0.006% P
-0.005%S)을 염산용액에서 산세후 10%의 수소농도 분위기에서 가열대 내의 강판온도를 변화시켜 열처리하고 용융아연 도금을 행한 후 기계적성질을 조사하여 이를 하기 표 1에 나타내었다.-0.005% S) after the pickling in hydrochloric acid solution and heat treatment by changing the temperature of the steel plate in the heating table in the hydrogen concentration atmosphere of 10% and the hot-dip galvanizing and then investigated the mechanical properties are shown in Table 1 below.
표 1에 의하면 본 발명에 의해 제조된 Cr첨가 용융도금 열연강판(발명강 1, 발명강 2)은 깊이 50mm 이상의 심한 가공을 요하는 전기스위치박스 제작에 필요한 도금강판의 최소 재질규격조건인 YS:17Kg/㎟ 이하, E1:45% 이상인 조건을 충족하여 사용이 가능하였다.According to Table 1, the Cr-added hot-dip hot-rolled steel sheet (Invention Steel 1, Invented Steel 2) manufactured by the present invention is YS, which is the minimum material specification condition of the plated steel sheet required for the production of an electrical switch box requiring a severe processing of 50 mm or more in depth: It was possible to meet the conditions of 17 Kg / mm 2 or less and E1: 45% or more.
반면 Cr함량이 0.3중량% 미만인 경우(비교강 1),혼립조직 형성에 따른 재질편차 및 고용탄소의 제고용에 따른 항복점 연신 발생에 의한 재질열화가 발생하였고, 0.5중량% 초과시(비교강 2)에는 Cr자체에 의한 강도 증가에 기인한 연성 저하가 크게 나타났다.On the other hand, when the Cr content is less than 0.3% by weight (comparative steel 1), material deterioration occurs due to material deviation due to the formation of the mixed structure and yield point stretching due to the enhancement of dissolved carbon, and exceeds 0.5% by weight (comparative steel 2). The decrease in ductility due to the increase in strength by Cr itself was large.
또한, 도금전 열처리온도가 500℃를 초과(비교강 3, 비교강 4)하면, 크롬카바이드 형태로 고용되어 있던 고용탄소가 급속히 재용해되어 항복강도가 상승하고, 항복점 연신율이 나타나고 연성이 크게 감소하여 스위치박스 가공시 대부분 파손이 발생하였다.In addition, if the heat treatment temperature before plating exceeds 500 ° C. (Comparative Steel 3, Comparative Steel 4), the solid solution carbon dissolved in the form of chromium carbide is rapidly redissolved to increase the yield strength, yield point elongation is elongated, and ductility is greatly reduced. As a result, most damage occurred during the processing of switch boxes.
실시예2Example 2
0.3중량%Cr 첨가강(0.002%C-0.14%Mn-0.006%P-0.005%S)에 B 함량을 변화시킨 강종에 대해 460℃ 도금욕에서 3초간 침적하여 도금부착량을 150g/㎡(단면기준)로 한 용융아연 열연강판을 제조후 내2차 가공취성을 평가한 결과를 표 2에 나타내었다.Steel grades with varying B content in 0.3 wt% Cr-added steels (0.002% C-0.14% Mn-0.006% P-0.005% S) were deposited for 3 seconds in a 460 ° C plating bath for 150 g / m2 (cross section basis). Table 2 shows the results of evaluating the secondary work brittleness after the manufacture of hot-dip galvanized steel sheet.
내2차 가공성은 1.6mm두께의 강판을 사용하여 드로잉비(Drawing ratio)가 2.1인 킵을 성형후옆으로 뉘어 90㎝ 높이에서 4.4㎏의 추를 자유낙하시켜 충격을 가해줄 때 취성파괴가 일어나는 온도(Ductile-Brittle Transition Temperature:The secondary workability is the temperature at which brittle fracture occurs when a 1.6mm-thick steel plate is used to lay a keep with a drawing ratio of 2.1 and form sideways after free molding. Ductile-Brittle Transition Temperature:
DBTT)를 측정하여 내2차 가공취성의 평가지수로 사용하였다.DBTT) was measured and used as an evaluation index of secondary work brittleness.
상기 표 2에 의하면 강중 B함량이 0.010% 미만인 강종의 경우(비교강 5, 비교강 6), 연성-취성 천이온도가 높아 내2차 가공취성에 취약함을 알 수 있다.According to Table 2, in the case of steel grade B less than 0.010% in steel (Comparative Steel 5, Comparative Steel 6), the ductile-brittle transition temperature is high, it is vulnerable to secondary work brittleness.
한편 발명강 3과 같이 B를 0.010∼0.030%범위 내로 첨가시, 연성-취성 천이온도가 크게 저하된 이유는 B의 입계편석에 의해 입계강도가 증가하였기 때문으로 추정된다.On the other hand, when B is added in the range of 0.010% to 0.030% as invented steel 3, the reason why the ductility-brittle transition temperature is greatly decreased is because grain boundary strength is increased by the grain boundary segregation of B.
그러나 B함량이 0.040%를 초과하면(비교강 7), 연성-취성 천이온도의 감소는 적은 반면, 페라이트로의 변태를 크게 지연시켜 TiC 석출억제에 따른 고용탄소량 증가로 재질이 크게 열화되는 문제점이 발생하였다.However, when the B content exceeds 0.040% (Comparative Steel 7), the decrease in the ductility-brittle transition temperature is small, but the material is significantly degraded due to the increase in the amount of solid carbon due to TiC precipitation suppression by significantly delaying the transformation into ferrite. This occurred.
실시예3Example 3
0.5%Cr첨가강(0.002%C-0.14%Mn-0.006%P-0.005%S)을 도금전 열처리온도 및 브러쉬롤 사용유무를 달리한 후 460℃ 도금욕에서 3초간 침적하여 도금부착량을 150g/㎡(단면기준)로 한 용융아연 열연강판을 여러가지 방법으로 도금밀착성을 시험한 결과를 하기 표 3에 나타내었다.After coating 0.5% Cr additive steel (0.002% C-0.14% Mn-0.006% P-0.005% S) with different heat treatment temperature and brush roll before plating, immerse it for 3 seconds in 460 ℃ plating bath for 150g / Table 3 shows the results of the plating adhesion test of the hot-dip galvanized steel sheet of m 2 (cross section basis) by various methods.
발명강 4와 같이 산세처리시 일부 잔존하는 크롬산화물을 브러쉬롤로 연삭하여 제거하고, 도금전 열처리 강판온도 500℃ 이하에서 열처리시 용융아연 열연강판의 도금밀착성은 매우 우수하였다.As invented steel 4, some residual chromium oxide was removed by grinding with a brush roll during pickling treatment, and the plating adhesion of the hot-dip galvanized steel sheet was excellent when the heat treatment was performed at a temperature of 500 ° C. or lower before the plating.
또한 본 실시예의 경우 형성한계도(Forming Limit Diagram;FLD)를 작성한 결과, 소지철이 파단될 때까지 도금층 박리가 발생하지 않았다.In addition, in the present embodiment, as a result of forming a Forming Limit Diagram (FLD), peeling of the plating layer did not occur until the base iron was broken.
그러나 강판온도가 500℃를 초과하면(비교강 8), 도금전 열처리시 Cr이 강판표면에 상당량 편석하여 크롬산화물을 형성하기 때문에 도금밀착성이 열화되었다.However, when the steel plate temperature exceeded 500 ° C. (comparative steel 8), the plating adhesion was degraded because Cr segregated to the surface of the steel sheet to form chromium oxide during heat treatment before plating.
또한 브러쉬롤을 사용하지 않은 경우(비교강 9), 열연산세후 일부 잔존하는 크롬계산화물로 인해 도금밀착성이 저하되는 것으로 나타났다.In addition, when the brush roll was not used (comparative steel 9), the plating adhesion was deteriorated due to the remaining chromium oxide after the thermal calculation.
상기 설명한 바와 같이 본 발명에 의하면, 전기스위치박스와 같이 고가공성이 요구되는 열연 용융아연 도금강판을 제조시, 기존의 제조방법과 비교하여 냉간압연 공정의 단축에 따른 제조비용 및 성에너지 절감의 이점이 있으며, 도금전 열처리에 따른 재질변화를 최소화할 수 있어서 우수한 가공성을 확보할 수 있고, 도금전처리 조건을 변경하여 도금밀착성을 확보함으로써 결과적으로 경제성 및 품질을 향상시켜 산업상 이용가치가 매우 크다.As described above, according to the present invention, when manufacturing a hot-rolled hot-dip galvanized steel sheet requiring high workability, such as an electric switch box, compared to the conventional manufacturing method, the advantages of reduction in manufacturing cost and sex energy according to the reduction of cold rolling process In addition, it is possible to minimize the change in the material due to the heat treatment before plating to ensure excellent processability, and by changing the plating pretreatment conditions to secure the adhesion of the coating, resulting in improved economic efficiency and quality, the industrial value is very high.
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| KR20160073493A (en) | 2014-12-16 | 2016-06-27 | 주식회사 포스코 | Method for manufacturing of galvanized steel sheet to improve an elogation and galvanized steel sheet manufactured thereby |
| KR20160074753A (en) | 2014-12-18 | 2016-06-29 | 주식회사 포스코 | Galvanized steel sheet having excellent elogation and method for manufacturing the same |
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| JPS56163250A (en) * | 1980-05-16 | 1981-12-15 | Nippon Steel Corp | Manufacture of galvanized hot rolled steel plate causing no blister |
| JPH0941110A (en) * | 1995-07-31 | 1997-02-10 | Kawasaki Steel Corp | Production of high tensile strength hot dip galvanized steel sheet |
| KR19980048988A (en) * | 1996-12-19 | 1998-09-15 | 김종진 | Manufacturing method of hot dip galvanized hot rolled steel sheet with excellent workability and plating surface quality |
| KR19980048991A (en) * | 1996-12-19 | 1998-09-15 | 김종진 | Method for manufacturing hot-dip galvanized steel sheet for electrical wire switch box using hot rolled disc |
| KR100270115B1 (en) * | 1996-11-19 | 2000-10-16 | 이구택 | The galvanizing coating method with hot rolled steel |
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- 1998-12-30 KR KR10-1998-0062068A patent/KR100370582B1/en not_active IP Right Cessation
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56163250A (en) * | 1980-05-16 | 1981-12-15 | Nippon Steel Corp | Manufacture of galvanized hot rolled steel plate causing no blister |
| JPH0941110A (en) * | 1995-07-31 | 1997-02-10 | Kawasaki Steel Corp | Production of high tensile strength hot dip galvanized steel sheet |
| KR100270115B1 (en) * | 1996-11-19 | 2000-10-16 | 이구택 | The galvanizing coating method with hot rolled steel |
| KR19980048988A (en) * | 1996-12-19 | 1998-09-15 | 김종진 | Manufacturing method of hot dip galvanized hot rolled steel sheet with excellent workability and plating surface quality |
| KR19980048991A (en) * | 1996-12-19 | 1998-09-15 | 김종진 | Method for manufacturing hot-dip galvanized steel sheet for electrical wire switch box using hot rolled disc |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20160073493A (en) | 2014-12-16 | 2016-06-27 | 주식회사 포스코 | Method for manufacturing of galvanized steel sheet to improve an elogation and galvanized steel sheet manufactured thereby |
| KR20160074753A (en) | 2014-12-18 | 2016-06-29 | 주식회사 포스코 | Galvanized steel sheet having excellent elogation and method for manufacturing the same |
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