KR100550324B1 - Method for preventing oxidation of press hardening process - Google Patents

Method for preventing oxidation of press hardening process Download PDF

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KR100550324B1
KR100550324B1 KR1020030099002A KR20030099002A KR100550324B1 KR 100550324 B1 KR100550324 B1 KR 100550324B1 KR 1020030099002 A KR1020030099002 A KR 1020030099002A KR 20030099002 A KR20030099002 A KR 20030099002A KR 100550324 B1 KR100550324 B1 KR 100550324B1
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cold rolled
rolled material
press
oxides
oxide
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KR20050067964A (en
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강수영
한상빈
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주식회사 포스코
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
    • 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
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
    • 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

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  • Engineering & Computer Science (AREA)
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Abstract

본 발명은 표면이 미려하고 정도가 높은 프레스 경화제품을 생산하기 위한 방법에 관한 것으로서, 소정의 가열로안에서 냉연 소재를 800~900도로 가열하되, 가열로내에서 상기 냉연 소재를 유지시키는 시간을 냉연 소재의 두께에 따라 2~10분으로 하여 프레스 금형에서 열간성형을 한 후 냉각수에 의한 급속 냉각을 하여도 상기 냉연 소재 표면에 형성된 산화물들이 치밀하도록 구조화하여 산화물들의 구조를 조밀하게 만들어 주므로서 열간성형 시 산화물(FeO, Fe3O4, F2O3)들이 박리되는 것을 방지하여, 표면이 미려하고, 정도가 높으며 균일한 경도를 형성한 프레스 경화제품 생산을 도모할 수 있다.

Figure 112003050370439-pat00001

냉간 소재, 열간 가공, 프레스, 템터 컬러, 박리, 산화물, 고착

The present invention relates to a method for producing a press-cured product having a beautiful surface and high precision, wherein the cold rolled material is heated in a predetermined heating furnace at 800 to 900 degrees, and the time for maintaining the cold rolled material in the heating furnace is cold rolled. After hot forming in press mold for 2 ~ 10 minutes depending on the thickness of the material, even though rapid cooling by coolant, the oxides formed on the surface of the cold rolled material are densely structured to make the structure of oxides compact. By preventing peeling of the oxide oxides (FeO, Fe3O4, F2O3), it is possible to produce a press-cured product having a beautiful surface, high precision and uniform hardness.

Figure 112003050370439-pat00001

Cold material, hot working, press, temper color, peeling, oxide, fixation

Description

프레스 경화 공정의 산화 방지방법{METHOD FOR PREVENTING OXIDATION OF PRESS HARDENING PROCESS} Anti-oxidation method of press hardening process {METHOD FOR PREVENTING OXIDATION OF PRESS HARDENING PROCESS}             

도 1은 본 발명에 따른 프레스 제품의 표면에 부착되는 산화물을 도시한 상태도.1 is a state diagram showing an oxide attached to the surface of a press product according to the present invention.

<도면의 주요 부분에 대한 부호의 설명><Explanation of symbols for the main parts of the drawings>

1: 냉연 소재 2: 산화물1: cold rolled material 2: oxide

3: 제품3: product

본 발명은 자동차의 연비 개선의 목적으로 하는 경량화를 위한 자동차 부품의 생산에 관한 것으로, 특히 냉연 소재를 일정 온도로 가열한 후 프레스 금형에서 열간 성형을 하고, 냉각수에 의해 급속 냉각을 하여도 냉연 소재 표면에 형성된 소정의 산화물들이 박리되지 않도록 구성되는 프레스 경화 공정의 산화 방지방법에 관한 것이다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of automotive parts for weight reduction for the purpose of improving the fuel efficiency of automobiles. In particular, the cold rolled material is heated to a certain temperature and then hot formed in a press die, and the cold rolled material is rapidly cooled by cooling water. The present invention relates to a method for preventing oxidation in a press hardening process, which is configured so that predetermined oxides formed on a surface do not peel off.

일반적으로, 종래에는 자동차에 소요되는 부품을 상온에서 프레스 성형하여 사용하였으나, 자동차의 무게를 줄여 경량화를 위하여 냉연 소재를 900도 이상으로 가열하여 프레스 금형에서 열간 성형을 한 후 급속 냉각을 통하여 고강도의 부품을 생산하였는데, 가열 작업 시 생성된 산화물(예를 드렁, FeO, Fe3O4,F2O3등)들이 들뜬 상태가 되어, 열간 프레스 작업 시 냉연 소재와 분리되어 제품의 냉각을 위하여 투입된 냉각수와 접촉되고 이로 인하여 제품 표면이 부식되어 가공성 저하와, 연속작업 시 분리된 산화물(FeO, Fe3O4,F2O3)에 의하여 금형의 정도가 저하되어 자주 청소를 해야하는 문제점이 발생하였다. 또한, 냉각을 위하여 투입된 냉각수에 의하여 제품 표면의 부식으로 가공성이 저하되고, 제품의 연속작업시 분리된 산화물이 금형 사이에 끼이면서 금형의 정도 유지를 위하여 산화물 제거를 자주해야하므로 생산성이 저하되며, 분리된 산화물들이 금형에 가공된 냉각수 홀을 막아 냉각수 불균형 공급에 의한 제품의 경도 차이가 나는 등의 문제점이 있었다.In general, in the past, the parts required for automobiles were used by press molding at room temperature, but in order to reduce the weight of the automobile, the cold rolled material was heated to 900 degrees or more, hot formed in a press die, and then rapidly cooled to achieve high strength. The parts were produced, and the oxides produced during the heating operation (eg, druning, FeO, Fe3O4, F2O3, etc.) were excited. The surface of the product was corroded and the workability was reduced, and the degree of mold was degraded by the separated oxides (FeO, Fe3O4, F2O3) during continuous operation, which caused frequent problems of cleaning. In addition, the workability is lowered due to corrosion of the surface of the product by the cooling water added for cooling, and the productivity is lowered because the separated oxide is stuck between the molds during the continuous operation of the product and the oxides need to be frequently removed to maintain the mold. There was a problem that the separated oxides block the cooling water holes processed in the mold and the hardness difference of the product due to the cooling water imbalance supply.

상기와 같은 문제점을 해결하기 위하여 안출된 것으로써 본 발명의 목적은 냉연 소재의 열간 가공을 원활히 수행할 수 있도록 구성되는 프레스 경화 공정의 산화 방지방법을 제공하는데 있다.SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preventing oxidation of a press hardening process which is configured to smoothly perform hot working of a cold rolled material.

본 발명의 다른 목적은 열간 가공후 급속 냉각 공정시 제품의 표면에 생성된 산화물을 상기 제품에 긴밀히 고착되도록 구성되는 프레스 경화 공정의 산화 방지방법을 제공하는데 있다. Another object of the present invention is to provide an oxidation preventing method of a press hardening process configured to closely adhere an oxide produced on a surface of a product to a product during a rapid cooling process after hot working.                         

본 발명의 또 다른 목적은 내연 소재의 열간 가공후 급속 냉각시 제품의 표면에 생성되는 산화물을 긴밀히 고착시켜 원활한 프레스 공정을 유도함으로써 생산성을 향상시킬 수 있도록 구성되는 프레스 경화 공정의 산화 방지방법을 제공하는데 있다.
It is still another object of the present invention to provide a method for preventing oxidation of a press hardening process configured to improve productivity by inducing a smooth press process by closely bonding oxides formed on a surface of a product during rapid cooling after hot working of an internal combustion material. It is.

상술한 바와 같은 목적을 해결하기 위하여 안출된 것으로서, 본 발명은 표면이 미려하고 정도가 높은 프레스 경화제품을 생산하기 위한 방법에 있어서, 소정의 가열로안에서 냉연 소재를 800~900도로 가열하되, 가열로내에서 상기 냉연 소재를 유지시키는 시간을 냉연 소재의 두께에 따라 2~10분으로 하여 프레스 금형에서 열간성형을 한 후 냉각수에 의한 급속 냉각을 하여도 상기 냉연 소재 표면에 형성된 산화물들이 치밀하도록 구조화하여 산화물들의 구조를 조밀하게 만들어 주므로서 열간성형 시 산화물(FeO, Fe3O4, F2O3)들이 박리되는 것을 방지함을 특징으로 한다.In order to solve the object as described above, the present invention is a method for producing a press-cured product with a beautiful surface and high precision, heating the cold-rolled material in a predetermined heating furnace to 800 ~ 900 degrees, heating The time for maintaining the cold rolled material in the furnace is 2 to 10 minutes depending on the thickness of the cold rolled material, and hot forming is performed in the press die, and the oxides formed on the surface of the cold rolled material are dense even after rapid cooling with a coolant. By making the structure of the oxide densely, the oxides (FeO, Fe3O4, F2O3) is prevented from being peeled off during hot forming.

이하 본 발명의 바람직한 실시예를 첨부된 도면을 참조하여 상세히 설명하면 다음과 같다. 그리고, 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단되는 경우 그 상세한 설명을 생략한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the case where it is determined that the gist of the present invention may be unnecessarily obscured, the detailed description thereof will be omitted.

도 1은 본 발명에 따른 프레스 제품의 표면에 부착되는 산화물을 도시한 상태도로써, 본 발명은 먼저 제품(3)을 생산하기 위하여 제단된 냉연 소재(1)를 미 도시된 가열로에 인입하고, 가열로를 조작하여 냉연 소재(1)의 온도가 800~900도가 될때까지 승온을 하고, 가열로의 온도가 800~900도가 되면 승온을 멈추며, 이때부터 가열로 내부에서 상기 냉연 소재(1)를 소정의 시간동안 유지시킨다. 상기 유지 시간은 냉연 소재의 두께에 따라 2~10분 사이로 한다.1 is a state diagram showing an oxide adhered to the surface of a press product according to the present invention, the present invention first introduces the cold-rolled material (1), which is cut in order to produce the product (3) into the furnace shown, The temperature of the cold rolled material 1 is increased to 800 to 900 degrees by operating a furnace, and the temperature is stopped when the temperature of the furnace is 800 to 900 degrees. From this time, the cold rolled material 1 is removed from the inside of the furnace. Hold for a predetermined time. The holding time is between 2 and 10 minutes depending on the thickness of the cold rolled material.

이때 냉연 소재(1)의 가열시간을 800~900도로 하는 이유는 900도 이상으로 가열 할 시 냉연 소재(1)의 표면에 산화물(2)의 형성은 양호하나, 하기 <표 1>에서 나타난 바와 같이 제품의 경도 측정 값들의 변화가 없으며 가열 시간이 길수록 제품 생산 시간에 영향을 주고, 냉연 소재(1)의 가열시간을 800도 이하로 할 경우 냉연 소재(1)의 표면에 발생하는 산화물(2)들의 구조가 서로 치밀하지 못하며, 간격이 발생하여 들떠있어 열간성형 작업 시 냉연 소재(1)가 금형에 의하여 밴딩 되면서 들떠있던 산화물(2)들이 냉연 소재(1)에서 분리되는 현상이 발생한다.The reason for the heating time of the cold rolled material (1) is 800 ~ 900 degrees because the formation of the oxide (2) is good on the surface of the cold rolled material (1) when heated to more than 900 degrees, as shown in <Table 1> Likewise, the hardness measurement values of the product do not change, and the longer the heating time affects the production time of the product, the oxide (2) generated on the surface of the cold rolled material (1) when the heating time of the cold rolled material (1) is 800 degrees or less. ) Structure is not dense with each other, and the gap occurs and the excitation occurs during the hot forming operation, as the cold rolled material (1) is bent by the mold, the floating oxide (2) is separated from the cold rolled material (1) occurs.

시험조건Exam conditions 경도 측정값Hardness measurement 가열온도Heating temperature (℃)(℃) 유지시간Retention time (분)(minute) 냉각Cooling 방법Way 시험편Test piece 종류Kinds 시험편Test piece 두께(mm)Thickness (mm) 1One 22 33 44 55 700700 33 급냉Quench 범퍼bumper 22 240.4240.4 267.3267.3 255.0255.0 255.0255.0 250.4250.4 33 217.8217.8 218.4218.4 215.8215.8 212.5212.5 210.1210.1 800800 33 501.5501.5 503.8503.8 502.5502.5 503.3503.3 505.8505.8 33 484.8484.8 488.7488.7 471.7471.7 471.7471.7 479.3479.3 900900 33 463.5463.5 474.7474.7 453.4453.4 470.2470.2 465.7465.7 33 446.4446.4 468.1468.1 467.2467.2 468.0468.0 481.6481.6 10001000 33 477.1477.1 480.9480.9 467.2467.2 473.2473.2 477.1477.1 33 480.9480.9 468.7468.7 477.8477.8 488.7488.7 474.1474.1

상기 냉연 소재(1)의 가열 후 가열로 내부에서 유지시간을 가지는 이유는 소재의 두께에 따라 차이를 가지며, 하기 <표 2>에 명시된 바와 같이 냉연 소재(1)가1.0t 이하이면 유지시간을 2분으로 하고, 1.0~2.0t이면 유지시간을2~3분, 2.0~3.0t이면 유지시간을3~4분, 3.0~3.5t이면 유지시간을4~5분,3.5~4.0t이면 유지 시간을5~6분, 4.0~4.5t이면 유지시간을6~8분,4.5t 이상이면 유지시간을8~10분 으로 하므로 서 냉연 소재(1)의 표면에 생성된 산화물(2)들의 구조가 조밀하게 되어 치밀한 산화물 조직으로 되어 냉연 소재(1)의 표면이 푸른색을 띤 템터컬러 현상이 되면서 냉연 소재(1)와 산화물(2)들이 분리되지 않음을 알 수 있다.The reason for having a holding time in the heating furnace after heating of the cold rolled material 1 has a difference depending on the thickness of the material, and as shown in Table 2 below, if the cold rolled material 1 is 1.0t or less, If it is 2 minutes, if it is 1.0 ~ 2.0t, holding time is 2-3 minutes, if it is 2.0 ~ 3.0t, holding time is 3-4 minutes, if it is 3.0 ~ 3.5t, holding time is 4-5 minutes, and if it is 3.5 ~ 4.0t The structure of the oxides (2) formed on the surface of the cold-rolled material (1) with a holding time of 5 to 6 minutes, 4.0 to 4.5t and holding time of 6 to 8 minutes and holding time of 4.5 to 5t or more It can be seen that the cold rolled material 1 and the oxides 2 are not separated as the densified structure becomes a dense oxide structure and thus the surface of the cold rolled material 1 becomes a blue color temperament phenomenon.

소재 두께(mm)Material thickness (mm) 유지시간(분)Retention time (minutes) 비고Remarks 1.0이하1.0 or less 22 발명 조건Invention condition 1.0~2.01.0-2.0 2~32 ~ 3 발명 조건Invention condition 2.0~3.02.0 ~ 3.0 3~43 ~ 4 발명 조건Invention condition 3.0~3.53.0-3.5 4~54 ~ 5 발명 조건Invention condition 3.5~4.03.5 to 4.0 5~65 ~ 6 발명 조건Invention condition 4.0~4.54.0 ~ 4.5 6~86 ~ 8 발명 조건Invention condition 4.5이상4.5 or more 8~108 ~ 10 발명 조건Invention condition

분명히, 청구항들의 범위내에 있으면서 이러한 실시예들을 변형할 수 있는 많은 방식들이 있다. 다시 말하면, 이하 청구항들의 범위를 벗어남 없이 본 발명을 실시할 수 있는 많은 다른 방식들이 있을 수 있는 것이다.Apparently, there are many ways to modify these embodiments while remaining within the scope of the claims. In other words, there may be many other ways in which the invention may be practiced without departing from the scope of the following claims.

본 발명에 의하면, 냉연소재 표면에 형성된 산화물(FeO, Fe3O4, F2O3)들이 치밀한 구조인 템터컬러화 되어 소재표면의 산화물(FeO, Fe3O4, F2O3)들의 구조가 조밀하게 된 상태에서 성형을 하므로서 표면이 미려하고, 정도가 높으며 균일한 경도를 형성한 프레스 경화제품 생산을 도모할 수 있는 효과가 있다.According to the present invention, the oxides (FeO, Fe3O4, F2O3) formed on the surface of the cold-rolled material are temperized, which is a dense structure, and the surfaces of the oxides (FeO, Fe3O4, F2O3) on the surface of the material are compacted to form a beautiful surface. And, the degree is high and there is an effect that can promote the production of press-cured products formed a uniform hardness.

Claims (1)

표면이 미려하고 정도가 높은 프레스 경화제품을 생산하기 위한 방법에 있어서,In the method for producing a press hardened product with a beautiful surface and high precision, 소정의 가열로안에서 냉연 소재를 800~900도로 가열하되, 가열로내에서 상기 냉연 소재를 유지시키는 시간을 냉연 소재의 두께에 따라 2~10분으로 하여 프레스 금형에서 열간성형을 한 후 냉각수에 의한 급속 냉각을 하여도 상기 냉연 소재 표면에 형성된 산화물들이 치밀하도록 구조화하여 산화물들의 구조를 조밀하게 만들어 주므로서 열간성형 시 산화물(FeO, Fe3O4, F2O3)들이 박리되는 것을 방지함을 특징으로 하는 프레스 경화 공정의 산화 방지방법.The cold rolled material is heated in a predetermined heating furnace at 800 to 900 degrees, and the time for maintaining the cold rolled material in the heating furnace is 2 to 10 minutes depending on the thickness of the cold rolled material. Press hardening process characterized in that the oxides (FeO, Fe3O4, F2O3) are prevented from peeling during hot forming by structuring densely the oxides formed on the surface of the cold rolled material even after rapid cooling To prevent oxidation.
KR1020030099002A 2003-12-29 2003-12-29 Method for preventing oxidation of press hardening process KR100550324B1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5767129A (en) * 1980-09-25 1982-04-23 Nippon Steel Corp Production of high-strength cold rolled steel plate for automobile
JPS5819441A (en) * 1981-07-28 1983-02-04 Nippon Kokan Kk <Nkk> Manufacture of high tensile cold rolled steel plate with low yield ratio and high burning hardenability
JPH0320407A (en) * 1989-06-19 1991-01-29 Kobe Steel Ltd Method for preventing oxidation of grain boundary in high strength cold-rolled steel sheet
KR950008708A (en) * 1993-09-17 1995-04-19 조말수 Manufacturing method of ultra-high strength cold rolled steel sheet with excellent spot weldability and press workability
KR960023166A (en) * 1994-12-26 1996-07-18 도자끼 시노부 Automotive steel sheet with excellent impact resistance and manufacturing method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5767129A (en) * 1980-09-25 1982-04-23 Nippon Steel Corp Production of high-strength cold rolled steel plate for automobile
JPS5819441A (en) * 1981-07-28 1983-02-04 Nippon Kokan Kk <Nkk> Manufacture of high tensile cold rolled steel plate with low yield ratio and high burning hardenability
JPH0320407A (en) * 1989-06-19 1991-01-29 Kobe Steel Ltd Method for preventing oxidation of grain boundary in high strength cold-rolled steel sheet
KR950008708A (en) * 1993-09-17 1995-04-19 조말수 Manufacturing method of ultra-high strength cold rolled steel sheet with excellent spot weldability and press workability
KR960023166A (en) * 1994-12-26 1996-07-18 도자끼 시노부 Automotive steel sheet with excellent impact resistance and manufacturing method thereof

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