KR20020049924A - A method for manufacturing cold forming steel wire rod for spring - Google Patents

A method for manufacturing cold forming steel wire rod for spring Download PDF

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Publication number
KR20020049924A
KR20020049924A KR1020000079249A KR20000079249A KR20020049924A KR 20020049924 A KR20020049924 A KR 20020049924A KR 1020000079249 A KR1020000079249 A KR 1020000079249A KR 20000079249 A KR20000079249 A KR 20000079249A KR 20020049924 A KR20020049924 A KR 20020049924A
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South Korea
Prior art keywords
wire rod
spring
less
wire
steel
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KR1020000079249A
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Korean (ko)
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서일권
이경수
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이구택
주식회사 포스코
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Priority to KR1020000079249A priority Critical patent/KR20020049924A/en
Publication of KR20020049924A publication Critical patent/KR20020049924A/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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

PURPOSE: Provided is a production process of wire rod for cold molding spring steel which rolls casting blooms to make a billet and controls conditions in grinding so that it minimizes surface decarbonization to improves life span in producing the spring. CONSTITUTION: In a wire rod for cold molding spring steel which is produced by casting steel wherein 0.40-0.70wt% of C, 1.2-1.6wt% of Si, 0.60-0.90wt% of Mn, 0.60-0.90wt% of Cr, less than 0.030wt% of P, less than 0.030wt% of S, 0.010-0.020wt% of Al, residual Fe and other impurities are mixed to make blooms and rolls by the billet, grinding for front side, reheating, wire rolling, cooling in water, winding and binding the wire rod, the production process of wire rod for cold molding spring steel is characterized by rotating a grinding wheel with 20-24 meshes in luminous intensity at 2000-4000 ppm and transferring the billet at 0.3-1.3m/sec.

Description

냉간성형 스프링강 선재의 제조방법{A METHOD FOR MANUFACTURING COLD FORMING STEEL WIRE ROD FOR SPRING}Manufacturing method of cold forming spring steel wire {A METHOD FOR MANUFACTURING COLD FORMING STEEL WIRE ROD FOR SPRING}

본 발명은 자동차 차체를 지지하고 노면의 충격으로부터 완충역할을 하는 자동차용 현가 스프링 선재의 제조방법에 관한 것으로, 보다 상세하게는 표면탈탄이 저감되고 피로수명이 향상되는 스프링용 선재를 제조하는 방법에 관한 것이다.The present invention relates to a method for manufacturing a suspension spring wire for automobiles that support an automobile body and cushion a road surface, and more particularly, to a method for manufacturing a spring wire rod with reduced surface decarburization and improved fatigue life. It is about.

자동차용 냉간성형 현가스프링은, 자동차 차체를 지지하고 노면의 충격으로부터 완충시키는 역할을 하는 소재로서, 종래에는 상기 스프링용 선재에 있어서,표면결함을 제어하여 최소한의 생산성을 확보하고자 하는 노력이 진행되어 왔다.Cold-formed suspension springs for automobiles are a material that serves to support the vehicle body and cushion the impact of the road surface. Conventionally, in the spring wire rod, efforts have been made to control surface defects to secure minimum productivity. come.

그러나, 스프링용 강 선재의 성분중에는 탄성확보를 위해 Si이 다량 함유되는데, 이것은 가열로내에서 소재표면부의 탈탄을 조장하는 역할을 하여, 도 1에 나타난 바와 같은 탄소고용도가 낮은 페라이트탈탄층을 형성시킨다. 상기 페라이트탈탄층은, 모재부 대비 탄소의 함유량이 적어 경도가 매우 낮기 때문에, 수냉 및 템퍼링처리에 의해서도 강도를 향상시킬 수 없다.However, a large amount of Si is contained in the components of the spring steel wire to secure elasticity, which serves to promote decarburization of the surface of the material in the heating furnace, thereby reducing the ferrite decarburization layer having low carbon utilization as shown in FIG. 1. To form. Since the ferrite decarburized layer has a low carbon content and a very low hardness, the strength cannot be improved even by water cooling and tempering.

이러한 소재를 이용해 현가용스프링을 제조하면, 스프링 표면에 작용하는 응력상태를 나타내는 도 2와 같이, 표면부에 고응력이 반복적으로 적용되어 표면부의 균열발생 원인으로 되고, 이에 따라 피로수명이 단축하게 되는 주요인으로 작용한다.When the suspension spring is manufactured using such a material, high stress is repeatedly applied to the surface portion as shown in FIG. 2 showing the stress state acting on the surface of the spring, causing cracks on the surface portion, thereby reducing fatigue life. Acts as the main factor.

상기한 문제점을 해결하기 위하여, 대한민국 특허출원 제99-63182호에서는 고실리콘강에서 가열로내 페라이트 탈탄발생 온도구간 속도를 조절하여 탈탄을 저감하는 기술을 제시한 바 있다.In order to solve the above problems, Korean Patent Application No. 99-63182 has proposed a technique for reducing the decarburization by controlling the speed of the ferrite decarburization temperature section in the furnace in high silicon steel.

한편, 냉간성형 스프링강의 경우에는, 통상적인 열간성형 스프링강과는 달리 절삭을 통한 표면부 제거가 곤란하므로, 소재상태에서 표면품질을 확보해야 하는 어려움이 있다. 즉, 도 3(a)에 나타난 바와 같은, 회전하는 바이트를 통과시켜 표면을 절삭하는 종래의 냉간성형 방법을 적용하면, 고주파에 의한 10초 이내의 급속가열시 표면의 가공경화부에 균열이 유발되는 가능성이 높아서, 스프링으로의 사용이 곤란하게 되는 것이다.On the other hand, in the case of cold-formed spring steel, unlike the conventional hot-formed spring steel, it is difficult to remove the surface portion by cutting, there is a difficulty in ensuring the surface quality in the state of the material. That is, if the conventional cold forming method of cutting the surface by passing through the rotating bite, as shown in Fig. 3 (a), the crack is caused in the work hardening of the surface during rapid heating within 10 seconds by high frequency It is highly likely to be used, which makes it difficult to use the spring.

이에 본 발명의 발명자들은 상기와 같은 문제점을 해결하기 위하여 연구 및 실험을 행하고 그 결과에 근거하여 제안된 것으로, 본 발명은 연속주조된 주편(블룸)을 압연하여 빌렛으로 만든 후 전연연마할 때 그 조건을 적절히 제어함으로써, 표면탈탄발생을 최소화하고 냉간성형 스프링제조시 피로수명을 향상할 수 있는, 스프링용강 선재의 제조방법을 제공하는데, 그 목적이 있다.In order to solve the above problems, the inventors of the present invention have conducted research and experiments, and have been proposed based on the results. The present invention has been made by rolling a continuous cast slab (bloom) into a billet, followed by pre-polishing. It is an object of the present invention to provide a method for producing a spring steel wire rod, which can minimize surface decarburization and improve fatigue life during cold forming spring by appropriately controlling the conditions.

도 1은 페라이트 탈탄층 및 모재부 조직을 나타내는 사진1 is a photograph showing the ferrite decarburized layer and the base material structure

도 2는 스프링 표면에 작용하는 응력을 나타내는 도면2 shows stresses acting on a spring surface;

도 3(a)는 종래 냉간스프링의 제조공정을 나타내는 도면Figure 3 (a) is a view showing a manufacturing process of a conventional cold spring

도 3(b)는 고주파 유도가열식을 적용하여 스프링을 제조하는 공정을 나타내는 도면Figure 3 (b) is a view showing a process for manufacturing a spring by applying a high frequency induction heating formula

상기 목적을 달성하기 위한 본 발명은,The present invention for achieving the above object,

중량%로, C: 0.40∼0.70%, Si: 1.2∼1.6%, Mn: 0.60∼0.90%, Cr: 0.60∼0.90%, P: 0.030% 이하, S: 0.030% 이하, Al: 0.010∼0.020%, 잔부 Fe 및 기타 불가피한 불순물로 조성되는 강을 연속주조하여 주편으로 제조한 후 빌렛으로 압연하고, 전면연마를 실시한 다음 재가열하고 선재압연한 후, 수냉하고 권취한 다음 상기 선재를 결속하는 것을 포함하여 이루어지는 냉간성형 스프링강 선재의 제조방법에 있어서,By weight%, C: 0.40 to 0.70%, Si: 1.2 to 1.6%, Mn: 0.60 to 0.90%, Cr: 0.60 to 0.90%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.020% , Continuous casting of steel composed of balance Fe and other unavoidable impurities, made into cast steel, rolled into billets, subjected to total polishing, then reheated, rolled wire, water-cooled and wound, and then binding the wire In the method for producing a cold formed spring steel wire rod,

상기 전면연마는, 조도가 20~24mesh인 연마휠을 2000~4000rpm의 속도로 회전시키면서 0.3~1.3m/sec의 속도로 빌렛을 이송하여 실시하는 것을 특징으로 하는 냉간성형 스프링강 선재의 제조방법에 관한 것이다.The front grinding is to produce a cold-formed spring steel wire, characterized in that carried out by transferring the billet at a speed of 0.3 ~ 1.3m / sec while rotating the polishing wheel having a roughness of 20 ~ 24mesh at a speed of 2000 ~ 4000rpm It is about.

이하, 본 발명에 대하여 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

본 발명에서 상기 C는 0.40~0.70%로 첨가하는 것이 바람직한데, 그 이유는 0.4% 미만에서는 현가용 스프링 등이 요구되는 강도를 확보하기 어렵고, 0.70%를 초과하면 인성확보가 어렵고, 제시된 성분계 범위내에서 급냉시 판상 마르텐사이트의 생성으로 인한 균열발생이 용이하기 때문이다.In the present invention, the C is preferably added at 0.40 to 0.70%, and the reason is that less than 0.4% is difficult to secure the required strength of the suspension spring, etc., if it exceeds 0.70%, toughness is difficult to be obtained, and the proposed component range This is because cracks are easily generated due to the formation of plate-like martensite during quenching.

상기 Si는 그 함량을 1.2~1.6%로 설정하는 것이 바람직한데, 그 이유는 그 함량이 1.2% 미만이면 규소가 페라이트에 고용되어 모재의 강도를 향상시키고 변형저항성을 높이는 효과가 미흡하고, 1.6%를 초과하면 표면탈탄발생이 커서 피로수명의 급격한 저하가능성이 크기 때문이다.The content of Si is preferably set to 1.2 to 1.6%. The reason is that if the content is less than 1.2%, silicon is dissolved in ferrite to improve the strength of the base material and increase the deformation resistance. If it exceeds, the surface decarburization is large and the fatigue life is likely to drop rapidly.

상기 Mn은 그 함량을 0.60~0.90%로 설정하는 것이 바람직한데, 그 이유는 그 함량이 0.60% 미만인 경우에는 소입성의 저하로 강도의 확보가 어렵고, 0.90%를 초과하는 경우에는 인성을 저하시키기 때문이다.The Mn is preferably set to a content of 0.60 to 0.90%. The reason is that when the content is less than 0.60%, it is difficult to secure the strength due to a decrease in the hardenability, and when the content exceeds 0.90%, the toughness is reduced. Because.

상기 Cr은 그 함량을 0.60~0.90%로 설정하는 것이 바람직한데, 그 이유는 그 함량이 0.60% 미만이면 고강도의 확보를 위한 충분한 소입효과가 없고, 0.90%를 초과하면 소재의 변형 저항성을 저하시키기 때문이다.The Cr is preferably set to a content of 0.60 to 0.90%, because if the content is less than 0.60%, there is no sufficient hardening effect for securing high strength, and if the content exceeds 0.90%, the deformation resistance of the material is lowered. Because.

상기 P과 S은 그 함량을 각각 0.030% 이하로 설정하는 것이 바람직하다. 만약, 그 함량이 0.030%를 초과하면 인의 경우 결정입계에 편석되어 인성을 저하시키고, 황의 경우는 유화물을 형성시킨다.P and S are preferably set to 0.030% or less, respectively. If the content is more than 0.030%, phosphorus segregates at grain boundaries to reduce toughness, and sulfur forms an emulsion.

상기 Al은 0.005∼0.020%로 하는 것이 바람직한데, 그 이유는 그 함량이 0.005%미만이면 결정입도의 조대화로 스프링으로 사용시 피로수명의 단축을 유발하고, 0.020%이상 첨가시 용강중 산소와 결합해 조대한 개재물을 형성하여 피로수명을 단축시키기 때문이다.The Al is preferably 0.005 to 0.020%. If the content is less than 0.005%, Al causes shortening of fatigue life when used as a spring due to coarsening of crystal grains, and when combined with oxygen in molten steel when added above 0.020% This is because the formation of coarse inclusions shortens the fatigue life.

상기와 같이 조성된 용강을 이용해 냉간성형 스프링용강 선재로 제조하는데, 그 공정을 다음과 같다.By using the molten steel formed as described above to manufacture a cold-formed spring steel wire rod, the process is as follows.

먼저, 상기와 같이 조성된 용강을 연속주조하는데, 이 때 주조속도는 0.70~0.80m/min로 하는 것이 바람직하다. 그 이유는, 상기 주조속도가 0.70m/min미만이면 용강의 과냉으로 인한 주조성 확보가 어렵고, 0.80m/min이상이면 중심부에 C, Si등의 편석이 발생되며 편석부위가 선재압연후까지 잔존하여 고주파 열처리시 시간내에 뜨임되지 못해 냉간성형 가공성의 확보가 어렵기 때문이다.First, continuous casting of molten steel formed as described above, wherein the casting speed is preferably set to 0.70 ~ 0.80m / min. The reason is that if the casting speed is less than 0.70m / min, it is difficult to secure castability due to supercooling of molten steel, and if it is more than 0.80m / min, segregation such as C, Si is generated in the center, and the segregation portion remains until after wire rolling. This is because it cannot be tempered in time during high frequency heat treatment, making it difficult to secure cold forming processability.

상기 주조후에는 경압하를 실시하여 주편으로 만드는데, 이 때 상기 경합하는 4~8mm로 실시하는 것이 바람직하다. 그 이유는, 8mm이상의 경압하를 실시하면 유해한 내부크랙이 유발되고 4mm미만의 경압하시는 편석저감의 효과가 없기 때문이다.After the casting, it is subjected to light pressure to form a cast. At this time, the contention is preferably performed at 4 to 8 mm. The reason for this is that when the pressure is reduced to 8 mm or more, harmful internal cracks are caused and the segregation reduction effect of pressure less than 4 mm is not provided.

그 다음, 상기 주편을 압연하여 빌렛으로 만들고 단면당 1.0~2.0mm의 깊이로 전면연마를 실시하는데, 1.0mm 미만으로 전면연마하면 표면흠의 제거가 충분하지 못하고 2.0mm초과시는 조압연시 요구되는 최소치수를 만족할 수 없기 때문에 바람직하지 못하다.Then, the cast is rolled into billets and subjected to total polishing at a depth of 1.0 to 2.0 mm per cross section. If the surface is polished to less than 1.0 mm, surface flaw is not sufficiently removed. It is not preferable because the minimum dimension cannot be satisfied.

한편, 본 발명에서는, 상기 전면연마시 표면탈탄을 저감하도록 하는 조건을 적용한다는데 그 특징이 있는데, 이하에서는 본 발명의 전면연마에 대하여 설명한다.On the other hand, in the present invention, there is a feature to apply the conditions to reduce the surface decarburization during the entire surface polishing, the following describes the surface polishing of the present invention.

본 발명에서는, 조도가 20~24mesh인 연마휠을 2000~4000rpm의 속도로 회전시키면서, 0.3~1.3m/sec의 속도로 빌렛을 이송하여 전면연마를 실시하는데, 그 이유는 상기 연마휠의 조도가 20mesh 미만인 경우에는 표면부 상태가 거칠어 탈탄반응의 활성화를 조장해 탈탄층이 잔존하여 피로수명의 향상에 제약이 있고, 24mesh를 초과하는 경우에는 연마속도가 느려 최소한의 생산성을 확보할 수 없기 때문이다.In the present invention, while rotating the polishing wheel having a roughness of 20 ~ 24mesh at a speed of 2000 ~ 4000rpm, transfer the billet at a speed of 0.3 ~ 1.3m / sec to perform the front polishing, because the roughness of the polishing wheel This is because when the surface area is less than 20 mesh, the surface part is rough, which promotes the activation of the decarburization reaction, and thus the decarburization layer remains, thereby limiting the fatigue life. When the surface exceeds 24 mesh, the polishing rate is slow and the minimum productivity cannot be obtained.

또한, 상기 연마휠의 회전속도가 2000rpm 미만이면 작업속도가 느려 최소한의 생산성을 확보할 수 없고 4000rpm을 초과하는 경우에는 연마칩이 표면부에 융착되어 표면품질을 저하시키기 때문이다.In addition, when the rotational speed of the polishing wheel is less than 2000rpm, the working speed is low to ensure the minimum productivity, and when the polishing speed exceeds 4000rpm, the polishing chip is fused to the surface portion to deteriorate the surface quality.

또한, 상기 전면연마시 빌렛의 이송속도가 0.3m/sec 미만이면 최소한의 생산성을 확보할 수 없으며, 1.3m/s를 초과하면 과도한 연마속도로 표면크랙을 유발할 수 있기 때문에 바람직하지 못하다.In addition, if the transfer speed of the billet during the front polishing is less than 0.3m / sec is not possible to ensure the minimum productivity, if it exceeds 1.3m / s it is not preferable because it may cause surface cracks with excessive polishing speed.

상기 조건으로 제조된 빌렛은 1000~1100℃의 온도범위로 재가열하는 것이 바람직한데, 그 이유는 선재가열로 온도가 1000℃미만인 경우에는 온도가 낮아서 선재압연이 어렵고 1100℃이상인 경우 고규소강으로 표면탈탄이 발생하기 때문이다.The billet manufactured under the above conditions is preferably reheated to a temperature range of 1000 to 1100 ° C. The reason is that when the temperature is less than 1000 ° C due to wire heating, the wire is difficult to roll due to low temperature. This happens because.

그 후, 통상의 방법으로 선재압연을 실시한 다음 냉각수량을 100~140Nm3/h로 하여 수냉하고 권취하는데, 상기 수냉시 냉각수량이 100Nm3/h 미만이면 공냉대에서 과도한 냉각으로 마르텐사이트 조직이 발생되고, 냉각수량이 140Nm3/h이상이면 냉각수에 의한 소재의 헌팅발생으로 긁힘성 표면결함이 증가하여 표면흠 검출 횟수가 증가하게 되어 바람직하지 못하다. 이로 인해, 스프링용 강선제조시 작업성의 저하를 초래한다.Thereafter, the wire is rolled in a conventional manner, followed by water cooling and winding with a cooling water amount of 100 to 140 Nm 3 / h. When the cooling water is less than 100 Nm 3 / h, the martensite structure is excessively cooled in an air cooling zone. If the amount of the coolant is greater than 140 Nm 3 / h, the scratching surface defects increase due to the hunting of the material by the coolant, which increases the frequency of surface flaw detection. This causes a decrease in workability when manufacturing spring steel wire.

상기와 같이 제조된 선재는 65~75BAR의 압력범위내에서 결속하는 것이 바람직한데, 그 이유는 65BAR미만의 압력으로 결속하면 선재의 쓰러짐 발생에 의해 표면결함의 발생이 증가되고, 75BAR를 초과한 압력으로 결속하면 선재링간의 마찰에 의한 결속흠이 증가하기 때문이다.The wire rod manufactured as described above is preferably bound within a pressure range of 65 to 75 BAR, because when bound at a pressure of less than 65 BAR, the occurrence of surface defects increases due to the collapse of the wire, and the pressure exceeds 75 BAR. This is because the binding defect due to the friction between the wire rings increases.

이하, 실시예를 통하여 본 발명의 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

[실시예]EXAMPLE

중량%로, C: 0.55%, Si: 1.40%, Mn: 0.70%, Cr: 0.71%, P: 0.014%, S:0.008%, s-Al: 0.030%를 함유하고, 잔부 Fe 및 기타 불가피한 불순물로 조성되는 강을 0.72m/min의 속도로 연속주조한 다음 6mm로 경압하하여 블룸으로 주조한 후, 160×160㎟로 강편압연하였다. 그 후, 하기 표 1 의 조건으로 강편을 단면당 1.5mm 깊이로 전면연마한 다음, 1050℃로 재가열하고 13 Φmm의 직경을 갖는 선재로 압연한 다음, 냉각수량을 120Nm3/h로 하여 수냉하였다. 이후, 권취하고 70BAR 의 압력을 가하여 선재를 결속하였다. 이 후, 페라이트 탈탄층의 깊이를 측정하고, 그 결과를 하기 표 1에 나타내었다. By weight, it contains C: 0.55%, Si: 1.40%, Mn: 0.70%, Cr: 0.71%, P: 0.014%, S: 0.008%, s-Al: 0.030%, balance Fe and other unavoidable impurities The steel was formed by continuous casting at a speed of 0.72m / min and then cast down to 6mm at a reduced pressure, then rolled into 160 × 160 ㎜. Thereafter, the steel pieces were completely polished to a depth of 1.5 mm per cross section under the conditions shown in Table 1, then reheated to 1050 ° C., rolled into a wire rod having a diameter of 13 Φ mm, and cooled by water to 120 Nm 3 / h. . Thereafter, the wire rod was bound by winding and applying a pressure of 70 bar. Thereafter, the depth of the ferrite decarburized layer was measured, and the results are shown in Table 1 below.

한편, 상기한 방법으로 제조된 강 선재는, 도 3(b)에 나타난 바와 같은 고주파유도가열식을 적용한 냉간성형스프링강 제조방법에 의해 스프링으로 제조한 후, 피로수명을 측정하고 그 결과를 하기 표 1에 나타내었다.On the other hand, the steel wire produced by the method described above, after being manufactured by a spring by the cold forming spring steel manufacturing method applying the high frequency induction heating formula as shown in Figure 3 (b), the fatigue life is measured and the results are shown in the following table 1 is shown.

구분division 연마휠조도(MESH)Polishing Wheel Roughness (MESH) 연마휠속도(RPM)Polishing Wheel Speed (RPM) 강편의이송속도(m/sec)Feed rate of steel piece (m / sec) 페라이트탈탄층깊이(mm,MAX)Ferrite Decarburized Layer Depth (mm, MAX) 피로수명(만회)Fatigue Life 빌명예1Honor 1 2222 25002500 1.01.0 0.010.01 7575 발명예2Inventive Example 2 2424 31003100 0.60.6 -- 6262 발명예3Inventive Example 3 2222 26002600 0.80.8 0.010.01 7171 발명예4Inventive Example 4 2424 29002900 0.60.6 0.010.01 6767 발명예5Inventive Example 5 2020 35003500 1.11.1 0.010.01 5050 발명예6Inventive Example 6 2222 27002700 0.50.5 0.010.01 6969 비교강1Comparative Steel 1 1414 20002000 0.70.7 0.050.05 2323 비교강2Comparative Steel 2 1818 40004000 0.90.9 0.040.04 2222 비교강3Comparative Steel 3 1616 30003000 0.80.8 0.050.05 2727

상기 표 2에 나타난 바와 같이, 본 발명의 발명예(1)~(6)은 페라이트탈탄층의 깊이가 0.01mm 이하로 표면결함 깊이의 감소효과가 있으며, 스프링 피로수명 횟수가 증가하는 것을 알 수 있다.As shown in Table 2, Examples (1) to (6) of the present invention has the effect of reducing the surface defect depth to the depth of the ferrite decarburized layer is less than 0.01mm, it can be seen that the number of spring fatigue life increases have.

상술한 바와 같은 본 발명에 의하면, 냉간성형 현가스프링 제조공법을 적용할 수 있는 스프링용 선재의 제조시 표면탈탄을 저감하고 피로수명을 확보할 수 있어서, 자동차용 현가 스프링 선재로 사용할 수 있는 효과가 있는 것이다.According to the present invention as described above, it is possible to reduce the surface decarburization and to ensure the fatigue life during the production of the spring wire rod to which the cold forming suspension gas spring manufacturing method can be applied, which can be used as a suspension spring wire for automobiles It is.

Claims (1)

중량%로, C: 0.40∼0.70%, Si: 1.2∼1.6%, Mn: 0.60∼0.90%, Cr: 0.60∼0.90%, P: 0.030% 이하, S: 0.030% 이하, Al: 0.010∼0.020%, 잔부 Fe 및 기타 불가피한 불순물로 조성되는 강을 연속주조하여 주편으로 제조한 후 빌렛으로 압연하고, 전면연마를 실시한 다음 재가열하고 선재압연한 후, 수냉하고 권취한 다음 상기 선재를 결속하는 것을 포함하여 이루어지는 냉간성형 스프링강 선재의 제조방법에 있어서,By weight%, C: 0.40 to 0.70%, Si: 1.2 to 1.6%, Mn: 0.60 to 0.90%, Cr: 0.60 to 0.90%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.020% , Continuous casting of steel composed of balance Fe and other unavoidable impurities, made into cast steel, rolled into billets, subjected to total polishing, then reheated, rolled wire, water-cooled and wound, and then binding the wire In the method for producing a cold formed spring steel wire rod, 상기 전면연마는, 조도가 20~24mesh인 연마휠을 2000~4000rpm의 속도로 회전시키면서 0.3~1.3m/sec의 속도로 빌렛을 이송하여 실시하는 것을 특징으로 하는 냉간성형 스프링강 선재의 제조방법The front grinding is a method of manufacturing a cold-formed spring steel wire, characterized in that carried out by transferring the billet at a speed of 0.3 ~ 1.3m / sec while rotating the polishing wheel having a roughness of 20 ~ 24mesh at a speed of 2000 ~ 4000rpm
KR1020000079249A 2000-12-20 2000-12-20 A method for manufacturing cold forming steel wire rod for spring KR20020049924A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114207168A (en) * 2019-07-12 2022-03-18 株式会社Posco Wire rod and steel wire for high strength spring and method of manufacturing the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114207168A (en) * 2019-07-12 2022-03-18 株式会社Posco Wire rod and steel wire for high strength spring and method of manufacturing the same
CN114207168B (en) * 2019-07-12 2023-08-15 株式会社Posco Wire rod and steel wire for high strength spring and method of manufacturing the same

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