KR20040037738A - Method for manufacturing lower arm connector with high strength and high toughness - Google Patents

Method for manufacturing lower arm connector with high strength and high toughness Download PDF

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KR20040037738A
KR20040037738A KR1020020066348A KR20020066348A KR20040037738A KR 20040037738 A KR20040037738 A KR 20040037738A KR 1020020066348 A KR1020020066348 A KR 1020020066348A KR 20020066348 A KR20020066348 A KR 20020066348A KR 20040037738 A KR20040037738 A KR 20040037738A
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South Korea
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carbon steel
strength
female connector
hot forging
lower female
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KR1020020066348A
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Korean (ko)
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고영상
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현대자동차주식회사
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Publication of KR20040037738A publication Critical patent/KR20040037738A/en

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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
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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

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

Abstract

PURPOSE: To manufacture a lower arm connector of bainitic non-quenched and tempered steel having superior mechanical properties by controlled cooling the hot forged low carbon steel after hot forging low carbon steel comprising chromium, aluminum, vanadium and titanium. CONSTITUTION: The method for manufacturing lower arm connector having high tensile strength and high toughness is characterized in that a lower arm connector formed of bainitic non-quenched and tempered steel is manufactured by controlled cooling the hot forged low carbon steel after hot forging a low carbon steel slab comprising 0.170 to 0.230 wt.% of C, 0.150 to 0.350 wt.% of Si, 1.900 to 2.100 wt.% of Mn, 0.030 wt.% or less of P, 0.020 to 0.050 wt.% of S, 0.150 to 0.350 wt.% of Cr, 0.015 to 0.045 wt.% of Al, 0.130 to 0.210 wt.% of V, 0.005 to 0.030 wt.% of Ti and a balance of Fe and other inevitable impurities, wherein the hot forging process is performed in the temperature range of 1,100 to 1,200 deg.C, and wherein the controlled cooling process is performed at a cooling rate of 15 to 20 deg.C/sec.

Description

고강도 고인성 로워 암 커넥터 제조방법{Method for manufacturing lower arm connector with high strength and high toughness}Method for manufacturing lower arm connector with high strength and high toughness}

본 발명은 고강도 고인성 로워 암 커넥터 제조방법에 관한 것으로서, 더욱 상세하게는 중탄소강 소재를 열간단조 후 방냉하고 이어 소입 및 소려 열처리하는 기존의 제조방법과는 달리, 크롬(Cr), 알루미늄(Al), 바나듐(V) 및 티타늄(Ti)을새로이 첨가하여 조성된 저탄소강을 사용하여 열간단조 후 제어냉각만 실시하여 제조함으로써, 단조공정 후 실시되던 소입 및 소려공정을 거치지 않고도 우수한 기계적 특성을 갖는 베이나이트계 비조질강의 로워 암 커넥터를 제조할 수 있고, 이에 제조 장비 및 공수의 축소, 비용 및 시간의 절감, 생산성 향상이 가능해지며, 특히 강도와 인성이 동시에 향상된 로워 암 커넥터를 제조할 수 있는 고강도 고인성 로워 암 커넥터 제조방법에 관한 것이다.The present invention relates to a high-strength high toughness lower female connector manufacturing method, and more specifically, unlike the conventional manufacturing method of cooling the medium-carbon steel material after hot forging, followed by quenching and heat treatment, chromium (Cr), aluminum (Al ), By using the low carbon steel newly added by the addition of vanadium (V) and titanium (Ti) to manufacture by performing only controlled cooling after hot forging, having excellent mechanical properties without undergoing the hardening and soaking process that was performed after the forging process It is possible to manufacture lower female connectors of bainite-based non-alloyed steel, which can reduce manufacturing equipment and man-hours, reduce costs and time, and improve productivity. In particular, lower female connectors with improved strength and toughness can be manufactured. It relates to a high strength high toughness lower female connector manufacturing method.

일반적으로 자동차 현가장치 부품 중 하나인 로워 암 커넥터(lower arm connector)(1)는, 첨부한 도 3에 도시한 바와 같이, 너클과 로워 암 부품을 연결시켜주는 중요한 보완부품이다.The lower arm connector 1, which is generally one of automobile suspension parts, is an important complementary part for connecting the knuckle and lower arm parts, as shown in FIG.

이러한 로워 암 커넥터(1)는 고강도 및 고인성을 필요로 하는 단조품으로서, 중탄소강을 소재로 하여 열간단조 후 조질처리하여 제조되고 있다.The lower female connector 1 is a forged product requiring high strength and high toughness. The lower female connector 1 is made of medium carbon steel and subjected to tempering after hot forging.

즉, 열간단조 후에 소입 및 소려의 열처리에 의한 조질처리를 하여, 소재 내에 마르텐사이트(martensite) 조직을 완전하게 생성시키고, 이를 통해 로워 암 커넥터의 용도에 요구되는 강도 및 인성이 확보되도록 하는 것이다.In other words, after hot forging, tempering treatment by heat treatment of quenching and heat treatment is performed to completely produce martensite structure in the material, thereby ensuring strength and toughness required for the use of the lower female connector.

상기 로워 암 커넥터의 제조과정을 좀 더 구체적으로 설명하면, 첨부한 도 4에 나타낸 바와 같이, 먼저 중탄소강 재질의 봉재를 1200∼1250℃ 정도의 고온으로 가열한 상태에서 부품형상으로 열간단조(hot forging)한 후 방랭한다.Referring to the manufacturing process of the lower female connector in more detail, as shown in the accompanying Figure 4, first, hot forging in the shape of parts in the state of heating the bar material of the medium carbon steel at a high temperature of about 1200 ~ 1250 ℃ (hot after forging).

이후, 냉각된 로워 암 커넥터 단조품은 850℃ 내외로 재가열 후 수냉 혹은 유냉시켜 재질을 경화시키는 소입공정(quenching)과, 이어 550∼650℃ 정도로 재가열 후 방냉하여 인성을 부여하는 소려공정(tempering)을 차례로 거치게 된다.Thereafter, the cooled lower female connector forged product is quenched to harden the material by re-heating to around 850 ° C. and then cooled or cooled by water, followed by a tempering process that gives toughness by cooling after reheating to about 550 to 650 ° C. In turn.

그러나, 상기와 같은 종래의 로워 암 커넥터 제조방법에서는 제품 강도 및 인성의 확보를 위하여 열간단조 후 반드시 별도의 소입 및 소려의 열처리공정을 거쳐야 하는 바, 이에 따른 장비 및 공수의 증가가 있었고, 비용 및 시간 측면에서도 매우 불리해지는 단점이 있었다.However, in the conventional method of manufacturing a lower female connector as described above, in order to secure product strength and toughness, a separate hardening and annealing heat treatment process must be performed after hot forging, thereby increasing the equipment and man-hour. There was also a disadvantage in terms of time.

또한, 종래의 제조방법에서는 로워 암 커넥터를 중탄소강을 소재로 하여 제조하였는 바, 이와 같이 제조된 로워 암 커넥터는, 작동시 복합응력, 즉 강한 굽힘응력과 비틀림응력을 받으면서 구동됨은 물론 고하중의 가혹한 작동조건하에서도 탁월한 내구성능을 가져야 함에도 불구하고, 중탄소강를 소재로 사용함에 따른 고부하 부품으로서의 한계가 있었다.In addition, in the conventional manufacturing method, since the lower female connector is manufactured using medium carbon steel, the lower female connector manufactured as described above is driven while being subjected to complex stress, that is, strong bending stress and torsional stress, as well as high load. Although it should have excellent durability even under severe operating conditions, there was a limitation as a high load part by using medium carbon steel as a material.

따라서, 본 발명은 상기와 같은 문제점을 해결하기 위하여 발명한 것으로서, 중탄소강 소재를 열간단조 후 방냉하고 이어 소입 및 소려 열처리하는 기존의 제조방법과는 달리, 크롬(Cr), 알루미늄(Al), 바나듐(V) 및 티타늄(Ti)을 새로이 첨가하여 조성된 저탄소강을 사용하여 열간단조 후 제어냉각만 실시하여 제조함으로써, 단조공정 후 실시되던 소입 및 소려공정을 거치지 않고도 우수한 기계적 특성을 갖는 베이나이트계 비조질강의 로워 암 커넥터를 제조할 수 있고, 이에 제조 장비 및 공수의 축소, 비용 및 시간의 절감, 생산성 향상이 가능해지며, 특히 강도와 인성이 동시에 향상된 로워 암 커넥터를 제조할 수 있는 고강도 고인성 로워 암 커넥터 제조방법을 제공하는데 그 목적이 있다.Therefore, the present invention was invented to solve the above problems, unlike the conventional manufacturing method of cooling the medium carbon steel material after hot forging, followed by quenching and heat treatment, chromium (Cr), aluminum (Al), Bainite having excellent mechanical properties without the hardening and soaking process that was performed after the forging process by manufacturing by controlling the cooling after hot forging using low carbon steel newly added with vanadium (V) and titanium (Ti). It is possible to manufacture lower female connectors made of non-manufactured steel, which can reduce manufacturing equipment and man-hours, reduce costs and time, and improve productivity. In particular, high-strength, high-strength lower female connectors can be manufactured with improved strength and toughness. It is an object of the present invention to provide a method for manufacturing a tough lower female connector.

도 1은 본 발명에 따른 제조과정을 보여주는 공정그래프1 is a process graph showing a manufacturing process according to the present invention

도 2는 본 발명의 제조방법에 의해 제조되는 로워 암 커넥터를 공정단계별로 도시한 도면2 is a view showing the lower arm connector manufactured by the manufacturing method of the present invention for each process step;

도 3은 통상의 로워 암 커넥터가 장착된 상태를 보여주는 도면3 is a view showing a state in which a conventional lower female connector is mounted;

도 4는 종래의 제조과정을 보여주는 공정그래프4 is a process graph showing a conventional manufacturing process

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

1: 로워 암 커넥터1: lower female connector

이하, 본 발명을 상세히 설명하면 다음과 같다.Hereinafter, the present invention will be described in detail.

본 발명은 탄소(C), 규소(Si), 망간(Mn), 인(P), 황(S)을 함유한 탄소강을 소재로 하여 로워 암 커넥터를 제조하는 방법에 있어서,The present invention relates to a method for manufacturing a lower female connector using carbon steel containing carbon (C), silicon (Si), manganese (Mn), phosphorus (P), and sulfur (S) as a material.

탄소(C) 0.170 ∼ 0.230 중량%, 규소(Si) 0.150 ∼ 0.350 중량%, 망간(Mn) 1.900 ∼ 2.100 중량%, 인(P) 0.030 중량% 이하, 황(S) 0.020 ∼ 0.050 중량%, 크롬(Cr) 0.150 ∼ 0.350 중량%, 알루미늄(Al) 0.015 ∼ 0.045 중량%, 바나듐(V) 0.130 ∼ 0.210 중량%, 티타늄(Ti) 0.005∼0.030 중량%, 잔여량의 철(Fe) 및 기타 불가피한 불순물로 조성된 저탄소강을 열간단조공정 후 제어냉각하여 베이나이트계 비조질강으로 이루어진 로워 암 커넥터를 제조하는 것을 특징으로 한다.0.170-0.230 wt% of carbon (C), 0.150-0.350 wt% of silicon (Si), 1.900-2.100 wt% of manganese (Mn), 0.030 wt% or less of phosphorus (P), 0.020-0.050 wt% of sulfur (S), chromium (Cr) 0.150 to 0.350% by weight, 0.015 to 0.045% by weight of aluminum (Al), 0.130 to 0.210% by weight of vanadium (V), 0.005 to 0.030% by weight of titanium (Ti), residual amounts of iron (Fe) and other unavoidable impurities The low carbon steel is controlled and cooled after the hot forging process to produce a lower female connector made of bainite-based non-coated steel.

특히, 상기 열간단조공정은 1100 ∼ 1200℃의 온도조건하에서 실시하는 것임을 특징으로 한다.In particular, the hot forging process is characterized in that it is carried out under the temperature conditions of 1100 ~ 1200 ℃.

또한, 상기 제어냉각은 냉각속도 15 ∼ 20℃/sec의 조건하에서 실시하는 것임을 특징으로 한다.In addition, the control cooling is characterized in that carried out under the conditions of the cooling rate of 15 to 20 ℃ / sec.

이하, 본 발명을 더욱 상세히 설명하면 다음과 같다.Hereinafter, the present invention will be described in more detail.

본 발명은 크롬(Cr), 알루미늄(Al), 바나듐(V) 및 티타늄(Ti)을 새로이 적정량 첨가한 저탄소강 소재를 단조공정 후 제어냉각하여 제품의 기지조직을 베이나이트화함으로써, 기존 대비 제품의 강도 및 인성을 동시에 향상시킬 수 있는 로워 암 커넥터 제조방법에 관한 것이다.The present invention is a low-carbon steel material containing a new addition of chromium (Cr), aluminum (Al), vanadium (V) and titanium (Ti) after the forging process to control and cool the base structure of the product by bainizing the base structure of the product, compared to the existing product It relates to a lower female connector manufacturing method that can improve the strength and toughness at the same time.

즉, 본 발명은 단조품 내 하부 베이나이트 조직 생성시 강도와 인성이 동시에 증가되는 성질을 이용한 것으로서, 제어냉각(공냉)시 경화능을 증가시키는 원소의 첨가로 저온 변태 생성물인 베이나이트(bainite) 조직을 생성시켜, 최종 완성된 로워 암 커넥터의 강도 및 인성을 동시에 향상시킬 수 있음 물론, 단조 후 별도의 열처리 공정을 삭제할 수 있도록 한 로워 암 커넥터 제조방법에 관한 것이다.That is, the present invention utilizes the property of simultaneously increasing the strength and toughness in the formation of the lower bainite structure in a forged product. The bainite structure, which is a low temperature transformation product due to the addition of an element which increases the hardenability during controlled cooling (air cooling), is used. By generating a, it is possible to improve the strength and toughness of the final lower arm connector at the same time, and, of course, relates to a method of manufacturing a lower arm connector to delete a separate heat treatment process after forging.

본 발명의 로워 암 커넥터 제조방법에서는, 상기와 같이 최종 제품 내에 베이나이트 조직을 생성시키기 위하여, 기존의 로워 암 커넥터 소재인 중탄소강에 비해 탄소(C)의 양을 줄이면서 크롬(Cr), 알루미늄(Al), 바나듐(V) 및 티타늄(Ti)을 새로이 첨가하여 조성한 저탄소강을 열간단조 후 제어냉각(공냉)하여 로워 암 커넥터를 제조하는 것에 가장 큰 특징이 있다.In the lower arm connector manufacturing method of the present invention, in order to create the bainite structure in the final product as described above, while reducing the amount of carbon (C) as compared to the existing lower arm connector material of medium carbon steel (Cr), aluminum The low carbon steel, which is newly added by adding (Al), vanadium (V), and titanium (Ti), has the greatest feature in manufacturing a lower female connector by hot-forging followed by controlled cooling (air cooling).

본 발명의 제조방법에서 로워 암 커넥터 제조시 사용되는 소재는 탄소(C) 0.170 ∼ 0.230 중량%, 규소(Si) 0.150 ∼ 0.350 중량%, 망간(Mn) 1.900 ∼ 2.100 중량%, 인(P) 0.030 중량% 이하, 황(S) 0.020 ∼ 0.050 중량%, 크롬(Cr) 0.150 ∼ 0.350 중량%, 알루미늄(Al) 0.015 ∼ 0.045 중량%, 바나듐(V) 0.130 ∼ 0.210 중량%, 티타늄(Ti) 0.005∼0.030 중량%, 잔여량의 철(Fe) 및 기타 불가피한 불순물로 조성된 저탄소강이다.In the manufacturing method of the present invention, the material used for manufacturing the lower female connector is 0.170 to 0.230 wt% of carbon (C), 0.150 to 0.350 wt% of silicon (Si), 1.900 to 2.100 wt% of manganese (Mn), and 0.030% of phosphorus (P). Wt% or less, sulfur (S) 0.020 to 0.050 wt%, chromium (Cr) 0.150 to 0.350 wt%, aluminum (Al) 0.015 to 0.045 wt%, vanadium (V) 0.130 to 0.210 wt%, titanium (Ti) 0.005 to Low carbon steel composed of 0.030% by weight, residual amounts of iron (Fe) and other unavoidable impurities.

상기 조성 중, 탄소(C)는 강에 있어서 강도를 증가시켜주고 열처리를 가능하게 하는 가장 중요한 원소이며, 본 발명에서는 인성 확보를 고려하는 동시에 그 함량이 너무 높으면 취성 및 경도가 증대됨을 고려하여 0.170 ∼ 0.230 중량%의 저탄소계로 설정하였다.Of the above composition, carbon (C) is the most important element to increase the strength and enable heat treatment in the steel, in the present invention, while considering the securing of toughness, while the content is too high 0.170 considering the increase in brittleness and hardness It set to the low carbon system of -0.230 weight%.

여기서, 상기 탄소의 함량을 상기 첨가범위에 비해 낮게 하면 기지조직을 마르텐사이트화하여 베이나이트 조직제어를 통해 강도를 높이는데 바람직하지 않다.Here, when the content of the carbon is lower than the addition range, it is not preferable to increase the strength through the bainite structure control by martensite the matrix structure.

상기 규소(Si)는 탈산제로서의 역할과 강도 확보를 위하여 첨가되는 것으로서, 0.150 ∼ 0.350 중량%로 첨가되며, 그 함량을 0.150 중량% 보다 낮게 하면 강도가 저하될 수 있고, 0.350 중량% 보다 높게 하면 오히려 인성이 저하되므로, 바람직하지 않다.The silicon (Si) is added to secure the role and strength as a deoxidizer, and is added at 0.150 to 0.350% by weight, and when the content is lower than 0.150% by weight, the strength may be lowered. Since toughness falls, it is not preferable.

또한, 강 중에 존재하는 황의 유해함을 방지하기 위하여 첨가되는 망간(Mn)은 치환형 고용체로 황과 결합하여 황화망간 개재물을 생성함과 동시에 결정립을 미세하게 하여 강도를 증가시키는 기능을 한다.In addition, manganese (Mn), which is added to prevent the harmfulness of sulfur present in the steel, is combined with sulfur as a substitutional solid solution to form manganese sulfide inclusions, and functions to increase the strength by making grains fine.

이러한 망간의 함량은 1.900 ∼ 2.100 중량%를 포함시켰는 바, 이때 함량이 1.900 중량% 미만에서는 원하는 강도를 얻을 수 없고, 2.100 중량% 초과시에는 성형성이 떨어지는 문제점이 있어, 바람직하지 않다.The content of such manganese is 1.900 to 2.100% by weight, where the desired strength cannot be obtained when the content is less than 1.900% by weight.

상기 망간은 황과 반응하여 망간황화합물을 형성, 가공성을 향상시키므로 본 발명에서는 고망간계열로 개발하였다.Since the manganese reacts with sulfur to form a manganese sulfur compound and improves processability, the present invention was developed as a high manganese series.

한편, 상기 인(P)은 0.030 중량% 이하로 제한하며, 상기 황(S)은 소성 변형온도가 낮은 황화물을 형성하여 제질물성을 약화시키므로 그 첨가범위를 0.020 ∼ 0.050 중량%로 제한한다.On the other hand, the phosphorus (P) is limited to 0.030% by weight or less, and the sulfur (S) forms a sulfide having a low plastic deformation temperature to weaken the material properties, so the addition range is limited to 0.020 to 0.050% by weight.

또한, 상기 크롬(Cr)은 인장강도 및 인성의 동시 증가와 조직 미세화를 위하여 첨가하는 것으로서, 0.150 중량% 미만으로 첨가하면 크롬탄화물 석출효과가 없어지는 문제점이 있고, 0.350 중량%를 초과하여 첨가하면 과대 석출 및 크롬질화물생성 등의 문제점이 있어, 바람직하지 않다In addition, the chromium (Cr) is added for simultaneous increase in tensile strength and toughness and microstructure, and when added below 0.150% by weight, there is a problem that the chromium carbide precipitation effect is lost, and when added in excess of 0.350% by weight Problems such as excessive precipitation and chromium nitride production are undesirable.

상기 티타늄(Ti)은 티타늄질화물(TiN) 형성으로 조직 미세화 및 강도 향상을 위하여 0.005 ∼0.030 중량%로 첨가하였으며, 상기 알루미늄(Al)은 제강중의 알루미늄질화물(AlN) 형성으로 적정 질소량을 조절하기 위하여 첨가하는 것으로서, 상기 첨가 범위를 벗어날 경우 유해한 질소 및 질화물 잔존의 문제점이 있으므로, 바람직하지 않다.The titanium (Ti) was added in an amount of 0.005 to 0.030% by weight in order to refine the structure and improve the strength by forming titanium nitride (TiN), the aluminum (Al) to adjust the appropriate nitrogen amount by forming the aluminum nitride (AlN) in steelmaking. In order to add, in order to remove harmful nitrogen and nitride when the product is out of the above range, it is not preferable.

또한, 상기 바나듐(V)은 강 중의 탄소와 반응하여 복합탄화물을 석출시켜 강도를 향상시키는데, 지나친 석출에 의한 취성의 증대를 방지하기 위하여 0.130 ∼ 0.210 중량%로 그 첨가범위를 제한하였다.In addition, the vanadium (V) to increase the strength by reacting with carbon in the steel to precipitate a composite carbide, to limit the addition range to 0.130 ~ 0.210% by weight in order to prevent the increase of brittleness due to excessive precipitation.

상기와 같은 조성으로 이루어진 합금강 소재를 이용하여 고강도 고인성 로워 암 커넥터를 제조하기 위해서는, 첨부한 도 1에 나타낸 바와 같이, 상기 조성의 저탄소강을 고온으로 가열한 상태에서 열간단조공정을 실시하여 해당 부품의 형상으로 성형하고, 이를 제어냉각(공냉)하여 제품을 완성하게 된다.In order to manufacture a high strength high toughness lower female connector using an alloy steel material having the composition described above, as shown in FIG. 1, a hot forging process is performed by heating a low carbon steel having the composition at a high temperature. It is molded into the shape of the part and controlled cooling (air cooling) to complete the product.

첨부한 도 2에서는 본 발명의 제조방법에 의해 제조되는 로워 암 커넥터를 공정단계별로 나타내었다.In FIG. 2, a lower arm connector manufactured by the manufacturing method of the present invention is shown for each process step.

본 발명의 제조방법에서, 열간단조는 소재를 1100 ∼ 1200℃의 온도로 가열한 후 실시하는 것이 바람직하며, 1200℃보다 높은 온도에서 열간단조를 실시할 경우, 결정립도가 급격히 커지면서 물성측면에서 취약해지는 바, 바람직하지 않다.In the production method of the present invention, the hot forging is preferably carried out after heating the material to a temperature of 1100 ~ 1200 ℃, when hot forging at a temperature higher than 1200 ℃, the grain size is rapidly increased and become weak in terms of physical properties Bar is not preferred.

상기 표 1에서는 단조시 가열온도와 소재 결정립도의 관계를 나타낸 것으로서, 결정립도가 작을수록 차량 부품에서의 물성(강도, 인성 등)이 우수해진다.Table 1 shows the relationship between the heating temperature during the forging and the grain size of the material. The smaller the grain size, the better the physical properties (strength, toughness, etc.) of the vehicle component.

가열온도에 따른 소재의 결정립도를 측정해 본 결과, 결정립도가 고온에서 급격히 커지므로, 물성측면에서 취약해짐을 방지하기 위해 가열온도를 1200가 넘지않도록 제한한다.As a result of measuring the grain size of the material according to the heating temperature, the grain size is rapidly increased at high temperature, so that the heating temperature is limited to not more than 1200 to prevent weakness in terms of physical properties.

한편, 단조공정 후 실시되는 제어냉각에서, 냉각속도는 하기 표 2에 나타낸 바와 같이 충격인성에 영향을 미치는 요소이다.On the other hand, in the controlled cooling carried out after the forging process, the cooling rate is a factor affecting the impact toughness as shown in Table 2 below.

본 발명의 제어방법에서는 냉각속도를 15 ∼ 20℃/sec의 범위 내에서 제어하는 것이 바람직하며, 15℃/sec 미만의 냉각속도에서는 페라이트 조직 등 이상 조직의 생성으로 물성치 변화가 있게 되므로 바람직하지 않고, 냉각속도를 20℃/sec보다 빠르게 할 경우 마르텐사이트 조직 등 이상조직의 생성으로 물성치 변화가 있어 바람직하지 않다.In the control method of the present invention, it is preferable to control the cooling rate within the range of 15 to 20 ° C./sec, and at the cooling rate of less than 15 ° C./sec, since the physical property changes due to the generation of abnormal structures such as ferrite tissue, it is not preferable. , If the cooling rate is faster than 20 ℃ / sec is the undesirable change in physical properties due to the generation of abnormal tissue such as martensite tissue.

이와 같이 하여, 상기 조성의 저탄소강을 열간단조 후 제어냉각하여 로워 암 커넥터를 제조하는 경우, 열간단조 후 가열로에서 재가열하였다가 냉각조에서 다시 냉각하는 별도의 열처리공정들을 거칠 필요 없이, 고강도 고인성의 제품을 제조할 수 있게 된다.Thus, in the case of manufacturing a lower female connector by controlling and cooling the low carbon steel of the composition after hot forging, the high strength deceased does not need to undergo a separate heat treatment process of reheating in a heating furnace after hot forging and cooling again in the cooling bath. It is possible to manufacture a sex product.

즉, 상기 조성의 저탄소강을 단조공정 후 제어냉각하여 로워 암 커넥터를 제조하게 되면, 제품 내에 기지조직이 베이나이트화되어 별도의 소입 및 소려의 열처리공정 없이도 기존 대비 강도와 인성이 동시에 향상된 제품을 제조할 수 있게 된다.That is, when the low-carbon steel of the composition is controlled and cooled after the forging process to manufacture the lower female connector, the base structure is bainized in the product, thereby improving the strength and toughness at the same time without the additional quenching and heat treatment process. It becomes possible to manufacture.

이하, 다음의 실시예에 의거 본 발명을 더욱 상세히 설명하는 바, 본 발명이 다음의 실시예로 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

실시예 1, 2Examples 1 and 2

본 발명의 제조방법에 의거하여, 다음의 표 3에 나타낸 바와 같은 조성 및 함량의 저탄소강을 1150℃의 온도로 가열한 상태에서 열간단조하고, 이어 3℃/sec의 냉각속도로 공냉하여 최종의 로워 암 커넥터를 제조하였으며, 이에 대한 인장강도, 항복강도, 피로강도 및 충격인성을 각각 측정하여 그 결과를 다음의 표 4에 나타내었다.According to the production method of the present invention, the low carbon steel of the composition and content as shown in the following Table 3 is hot forged while heated to a temperature of 1150 ℃, and then air-cooled at a cooling rate of 3 ℃ / sec to the final The lower female connector was manufactured, and tensile strength, yield strength, fatigue strength, and impact toughness were measured, respectively, and the results are shown in Table 4 below.

비교예 1, 2Comparative Examples 1 and 2

종래의 제조방법에 의거하여, 표 3에 나타낸 바와 같은 조성 및 함량의 중탄소강을 1250℃의 온도로 가열한 상태에서 열간단조하고, 이어 방냉, 재가열(850℃, 90min), 유냉, 템퍼링(600℃, 120min) 및 방냉하여 최종의 로워 암 커넥터를 제조하였으며, 이에 대한 인장강도, 항복강도, 피로강도 및 충격인성을 측정하여 그 결과를 다음의 표 4에 나타내었다.Based on the conventional manufacturing method, hot forging was carried out in the state of heating the medium carbon steel of the composition and content as shown in Table 3 to a temperature of 1250 ℃, followed by cooling, reheating (850 ℃, 90 min), oil cooling, tempering (600 ℃, 120min) and allowed to cool to prepare a final lower female connector, the tensile strength, yield strength, fatigue strength and impact toughness were measured for the results are shown in Table 4 below.

다음의 표 3은 실시예 1, 2와 비교예 1, 2의 소재 조성 및 함량을 비교, 예시하여 나타낸 것이다.Table 3 below shows and compares the material compositions and contents of Examples 1 and 2 with Comparative Examples 1 and 2.

다음의 표 4는 상기 표 3의 각 조성 및 함량을 갖는 소재를 사용하여 본 발명의 제조방법(실시예 1, 2) 및 기존의 제조방법(비교예 1, 2)에 의거 제조한 각로워 암 커넥터의 인장강도, 항복강도, 피로강도 및 충격인성을 해당 KS 규정에 근거하여 측정한 결과를 나타낸 것이다.Table 4 below is a corner arm manufactured according to the production method of the present invention (Examples 1 and 2) and the existing production method (Comparative Examples 1 and 2) using the materials having the respective compositions and contents of Table 3. The tensile strength, yield strength, fatigue strength and impact toughness of the connector are measured based on the relevant KS regulations.

측정 결과를 살펴보면, 상기 표 4에서 나타낸 바와 같이, 본 발명의 제조방법(실시예 1, 2)에 의거 제조한 로워 암 커넥터에서는 열간단조 후 별도의 열처리공정(소입 및 소려공정)을 거치지 않았음에도 불구하고 종래의 제조방법에 의거 제조한 로워 암 커넥터(비교예 1, 2)에 비해 강도와 인성이 모두 향상됨음을 알 수 있었다.Looking at the measurement results, as shown in Table 4, in the lower female connector manufactured according to the manufacturing method (Examples 1 and 2) of the present invention, even after the hot forging did not undergo a separate heat treatment process (hardening and soaking process) Nevertheless, it was found that both strength and toughness were improved compared to the lower female connectors (Comparative Examples 1 and 2) manufactured according to the conventional manufacturing method.

이상에서 살펴본 바와 같이, 본 발명에 따른 고강도 고인성 로워 암 제조방법에 의하면, 중탄소강 소재를 열간단조 후 방냉하고 이어 소입 및 소려 열처리하는 기존의 제조방법과는 달리, 크롬(Cr), 알루미늄(Al), 바나듐(V) 및 티타늄(Ti)을 새로이 첨가하여 조성된 저탄소강을 사용하여 열간단조 후 제어냉각만 실시하여 제조함으로써, 단조공정 후 실시되던 소입 및 소려공정을 거치지 않고도 우수한 기계적 특성을 갖는 베이나이트계 비조질강의 로워 암 커넥터를 제조할 수 있고, 이에 제조 장비 및 공수의 축소, 비용 및 시간의 절감, 생산성 향상이 가능해지며, 특히 강도와 인성이 동시에 향상된 로워 암 커넥터를 제조할 수 있는 효과가 있다.As described above, according to the high-strength high toughness lower arm manufacturing method according to the present invention, unlike the conventional manufacturing method of cooling the medium carbon steel material after hot forging, followed by quenching and annealing, chromium (Cr), aluminum ( By using low carbon steel newly prepared by newly adding Al), vanadium (V) and titanium (Ti), it is manufactured by only controlling cooling after hot forging, so that it has excellent mechanical properties without undergoing the hardening and soaking process performed after the forging process. It is possible to manufacture a lower female connector of bainite-based non-alloyed steel, which can reduce manufacturing equipment and labor, reduce cost and time, and improve productivity, and in particular, can produce a lower female connector with improved strength and toughness. It has an effect.

Claims (3)

탄소(C), 규소(Si), 망간(Mn), 인(P), 황(S)을 함유한 탄소강을 소재로 하여 로워 암 커넥터를 제조하는 방법에 있어서,In the method for producing a lower female connector using carbon steel containing carbon (C), silicon (Si), manganese (Mn), phosphorus (P), and sulfur (S), 탄소(C) 0.170 ∼ 0.230 중량%, 규소(Si) 0.150 ∼ 0.350 중량%, 망간(Mn) 1.900 ∼ 2.100 중량%, 인(P) 0.030 중량% 이하, 황(S) 0.020 ∼ 0.050 중량%, 크롬(Cr) 0.150 ∼ 0.350 중량%, 알루미늄(Al) 0.015 ∼ 0.045 중량%, 바나듐(V) 0.130 ∼ 0.210 중량%, 티타늄(Ti) 0.005∼0.030 중량%, 잔여량의 철(Fe) 및 기타 불가피한 불순물로 조성된 저탄소강을 열간단조공정 후 제어냉각하여 베이나이트계 비조질강으로 이루어진 로워 암 커넥터를 제조하는 것을 특징으로 하는 고강도 고인성 로워 암 커넥터 제조방법.0.170-0.230 wt% of carbon (C), 0.150-0.350 wt% of silicon (Si), 1.900-2.100 wt% of manganese (Mn), 0.030 wt% or less of phosphorus (P), 0.020-0.050 wt% of sulfur (S), chromium (Cr) 0.150 to 0.350% by weight, 0.015 to 0.045% by weight of aluminum (Al), 0.130 to 0.210% by weight of vanadium (V), 0.005 to 0.030% by weight of titanium (Ti), residual amounts of iron (Fe) and other unavoidable impurities Method for producing a high strength high toughness lower female connector, characterized in that the low-carbon steel after hot forging process controlled cooling to manufacture a lower female connector made of bainite-based non-coated steel. 제 1 항에 있어서, 상기 열간단조공정은 1100 ∼ 1200℃의 온도조건하에서 실시하는 것임을 특징으로 하는 로워 암 커넥터 제조방법.The method of claim 1, wherein the hot forging step is performed under a temperature condition of 1100 to 1200 ° C. 제 1 항에 있어서, 상기 제어냉각은 냉각속도 15 ∼ 20℃/sec의 조건하에서 실시하는 것임을 특징으로 하는 고강도 고인성 로워 암 커넥터 제조방법.The method of claim 1, wherein the controlled cooling is performed under a condition of a cooling rate of 15 to 20 ° C./sec.
KR1020020066348A 2002-10-30 2002-10-30 Method for manufacturing lower arm connector with high strength and high toughness KR20040037738A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112522610A (en) * 2020-11-18 2021-03-19 北京交通大学 V-Ti composite bainite non-quenched and tempered steel structure and manufacturing method thereof
WO2023145838A1 (en) * 2022-01-28 2023-08-03 Ｊｆｅスチール株式会社 Steel component and production method for same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5763628A (en) * 1980-10-03 1982-04-17 Daido Steel Co Ltd Production of forge hardened parts
JPS62205245A (en) * 1986-03-04 1987-09-09 Aichi Steel Works Ltd Non-heattreated steel for hot forging
KR920012499A (en) * 1990-12-31 1992-07-27 정명식 Heat treatment omitted hot forging steel with excellent toughness
JPH04210449A (en) * 1990-12-12 1992-07-31 Toa Steel Co Ltd High toughness non-heat treated steel for hot forging
KR950000908A (en) * 1993-06-16 1995-01-03 박득표 Manufacturing method of non-coated steel for high toughness hot forging
KR20020053398A (en) * 2000-12-27 2002-07-05 이계안 A microalloyed steel with high strength bainitic structure
KR20020068094A (en) * 2001-02-20 2002-08-27 한국기계연구원 High strength microalloyed steel having bainite structure for hot forging and manufacturing method therefor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5763628A (en) * 1980-10-03 1982-04-17 Daido Steel Co Ltd Production of forge hardened parts
JPS62205245A (en) * 1986-03-04 1987-09-09 Aichi Steel Works Ltd Non-heattreated steel for hot forging
JPH04210449A (en) * 1990-12-12 1992-07-31 Toa Steel Co Ltd High toughness non-heat treated steel for hot forging
KR920012499A (en) * 1990-12-31 1992-07-27 정명식 Heat treatment omitted hot forging steel with excellent toughness
KR950000908A (en) * 1993-06-16 1995-01-03 박득표 Manufacturing method of non-coated steel for high toughness hot forging
KR20020053398A (en) * 2000-12-27 2002-07-05 이계안 A microalloyed steel with high strength bainitic structure
KR20020068094A (en) * 2001-02-20 2002-08-27 한국기계연구원 High strength microalloyed steel having bainite structure for hot forging and manufacturing method therefor

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112522610A (en) * 2020-11-18 2021-03-19 北京交通大学 V-Ti composite bainite non-quenched and tempered steel structure and manufacturing method thereof
CN112522610B (en) * 2020-11-18 2022-03-25 北京交通大学 V-Ti composite bainite non-quenched and tempered steel structure and manufacturing method thereof
WO2023145838A1 (en) * 2022-01-28 2023-08-03 Ｊｆｅスチール株式会社 Steel component and production method for same
JP7380957B1 (en) * 2022-01-28 2023-11-15 Ｊｆｅスチール株式会社 Steel parts and their manufacturing method

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