KR950007785B1 - Making method of high tension wire rod - Google Patents
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- KR950007785B1 KR950007785B1 KR1019930010994A KR930010994A KR950007785B1 KR 950007785 B1 KR950007785 B1 KR 950007785B1 KR 1019930010994 A KR1019930010994 A KR 1019930010994A KR 930010994 A KR930010994 A KR 930010994A KR 950007785 B1 KR950007785 B1 KR 950007785B1
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Abstract
Description
제1도는 발명재와 비교재의 조직사진.1 is a tissue photograph of the invention and the comparative material.
본 발명은 열간압연 직후 코일(coil)상으로 권취된 선재를 강제공냉 시키므로서 인장강도를 향상시킨 대경선재의 제조방법에 관한 것이다.The present invention relates to a method for producing a large diameter wire rod which is improved in tensile strength by forcibly air-cooling the wire rod wound on a coil immediately after hot rolling.
일반적으로, 열간압연선재는 열간압연직후 소정의 온도까지 분사된 냉각수로서 수냉시킨 다음에 코일상으로 권취한 후에 강제공냉시킨다. 그러나, 탄소농도가 공석조성 이상이고, 대경선재(통상 직경 10mmψ이상)인 경우에는 강제공냉에 의해서 충분히 급냉시킬 수 없기 때문에 선재 중심부에 초석 시멘타이트가 발생하기도 하고, 충분한 인장강도도 확보할 수 없었다. 제한된 강제공냉조건하에서 인장강도를 높이기 위하여 탄소농도를 높이면 선재중심부에 초석 시멘타이트가 발생되어 신선성(drawability)이 나쁘게 된다. 따라서 제한된 강제공냉조건과 제한된 탄소농도의 조건에서 인장강도가 높은 대경선재를 제조하기 위해서 지금까지는 Cr, V 등의 합금원소를 첨가하여 강재자체의 냉각능을 향상시키는 방법이 주류를 이루고 있었다. 그러나 인장강도를 향상시킬 목적으로 합금원소의 첨가에 의한 냉각능을 향상시키는 방법은 오히려 선재중심부에 저온조직을 유발시킬 염려가 있고, 초석 시멘타이트의 발생을 억제시킬 수 있는 근본적인 대안은 아니었다.In general, hot-rolled wire rods are cooled by water as cooling water injected to a predetermined temperature immediately after hot rolling, and then coiled onto a coil, followed by forced air cooling. However, when the carbon concentration is higher than the vacancy composition and large diameter wire (usually 10 mm φ or more), it cannot be sufficiently quenched by forced air cooling, resulting in the formation of cornerstone cementite in the center of the wire rod and insufficient tensile strength. Increasing the carbon concentration to increase the tensile strength under limited forced air cooling conditions results in the formation of cornerstone cementite in the center of the wire rod, resulting in poor drawability. Therefore, in order to manufacture large diameter wire rods with high tensile strength under limited forced air cooling conditions and limited carbon concentrations, methods of improving the cooling ability of steel materials by adding alloy elements such as Cr and V have been the mainstream. However, in order to improve the tensile strength, the method of improving the cooling ability by the addition of alloying elements is likely to cause low temperature structure in the center of the wire rod, and is not a fundamental alternative to suppress the formation of cementite cementite.
이하, 본 발명은 강성분, 열간마무리 압연온도 및 냉각조건을 적절히 제어하므로서 초석 시멘타이트의 발생을 억제시켜 신선성을 향상시키고, 또한 높은 인장강도를 갖는 대경선재를 제공하고자 하는데, 그 목적이 있다.Hereinafter, an object of the present invention is to provide a large-size wire rod having a high tensile strength by improving the freshness by suppressing the generation of cementite cementite while appropriately controlling the steel component, hot finish rolling temperature, and cooling conditions.
이하, 본 발명에 대하여 상세히 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.
본 발명은 대경선재를 제조하는 방법에 있어서, 중량%로, C : 0.78∼0.82%, Si : 0.3∼1.0%, Mn : 0.6∼0.9%, P : 0.02% 이하, S : 0.02% 이하, Cr : 0.2∼0.5%, Al : 0.02∼0.1%, V : 0.01∼0.1%, N : 0.006% 이하, 잔부 Fe 및 기타 불가피한 불순물로 조성되는 고탄소 강재를 1,000∼1,100℃의 마무리압연 온도조건으로 열간압연한후, 분사된 냉각수로 780∼850℃까지 냉각한 다음, 코일상으로 권취하고 550℃까지 4 ∼10℃/sec의 냉각속도로 강제공냉시켜 고강도 대경선재를 제조하는 방법에 관한 것이다.The present invention provides a method for producing a large diameter wire, in weight%, C: 0.78 to 0.82%, Si: 0.3 to 1.0%, Mn: 0.6 to 0.9%, P: 0.02% or less, S: 0.02% or less, Cr : 0.2 to 0.5%, Al: 0.02 to 0.1%, V: 0.01 to 0.1%, N: 0.006% or less, hot carbon steel composed of residual Fe and other unavoidable impurities is hot-pressed at a finish rolling temperature of 1,000 to 1,100 ° C. After rolling, it is cooled to 780-850 degreeC with the sprayed cooling water, it winds up to a coil form, and it is related with the method of manufacturing a high strength large diameter wire by forcibly air-cooling at a cooling rate of 4-10 degreeC / sec to 550 degreeC.
이하, 상기 성분 한정 이유 등에 대하여 설명한다.Hereinafter, the reason for component limitation and the like will be described.
상기 탄소(C)의 함량이 0.82중량%(이하, ˝%˝라 칭함) 이상인 경우에는 초석 시멘타이트의 발생에 의해 신선성이 나빠지고, 또 신선재의 중심에 미세균열이 생기므로 인장강도, 단면감소율 및 비틀림강도가 떨어지고, 그 함량이 0.77% 이하인 경우에는 냉각속도가 느릴때 초석 페라이트가 발생하여 인장강도와 단면감소율이 떨어져 신선성이 나빠지므로, 상기 탄소의 함량은 0.79∼0.82%로 제한하는 것이 바람직하다.When the content of carbon (C) is 0.82 wt% or more (hereinafter referred to as ˝% ˝), the freshness deteriorates due to the generation of cornerstone cementite, and microcracks occur in the center of the wire, so that the tensile strength and the cross-sectional reduction rate And the torsional strength is lower, and the content is less than 0.77%, because the cornerstone ferrite is generated when the cooling rate is slow and the tensile strength and the cross-sectional reduction rate are lowered, resulting in poor freshness. Therefore, the carbon content is limited to 0.79 to 0.82%. desirable.
강중의 실리콘(Si)은 탈산제의 역할도 하지만, 고탄소강의 퍼얼라이트 조직에서는 퍼얼라이트를 구성하는 시멘타이트에 거의 고용하지 않고 페라이트에 고용되기 때문에 공석조성 이상의 탄소농도를 갖는 경우에는 초석 시멘타이트의 석출을 억제하고, 페라이트를 고용강화시켜 퍼얼라이트 전체의 강도를 향상시킬 뿐만 아니라 공석변태온도를 상승시켜서 퍼얼라이트를 미세화시키는 역활을 한다.Although silicon (Si) in steel also serves as a deoxidizer, in high carbon steels, it is hardly employed in the cementite constituting the pearlite, so it is employed in ferrite. It suppresses and strengthens ferrite so that not only improves the strength of the whole pearlite, but also increases the vacancy transformation temperature to play a role of making the pearlite finer.
상기 실리콘의 함량이 0.3% 이하인 경우에는 퍼얼라이트를 구성하는 페라이트 (pearlitic ferrite ; 이하 ˝퍼얼라이틱 페라이트˝라 칭함)의 강화효과와 초석 시멘타이트의 생성억제효과가 떨어지며, 그 함량이 1.0% 이상인 경우에는 퍼얼라이틱 페라이트가 취화되어 전체적으로는 오히려 단면감소율이 떨어져서 신선성이 나빠지게 되므로 상기 실리콘의 함량은 0.3∼1.0%로 제한하는 것이 바람직하다.When the content of the silicon is less than 0.3%, the strengthening effect of the ferrite (pearlitic ferrite; hereinafter called "perial ferrite") constituting the pearlite and the suppression effect of the formation of the cementite cementite is inferior, and the content is more than 1.0% Since the ferritic ferrite is embrittled and the overall cross-sectional reduction rate is lowered, the freshness is worsened, so the content of the silicon is preferably limited to 0.3 to 1.0%.
상기 망간(Mn)의 함량이 0.6% 이하인 경우에는 강도의 감소 및 퍼얼라이트의 핵생성속도가 너무 빠르기 때문에 미세한 퍼얼라이트 조직을 얻기 어렵고, 0.9% 이상인 경우에는 망간의 편석에 의한 저온조직이 발생될 염려가 있고, 또한 퍼얼라이트 변태를 너무 지연시키기 때문에 선재공장의 공냉대에서 변태가 완전히 끝나지 않아 조업효율이 떨어지므로, 상기 망간의 함량은 0.6∼0.9%로 제한하는 것이 바람직하다.When the content of manganese (Mn) is 0.6% or less, it is difficult to obtain a fine pearlite structure because the strength decreases and the nucleation rate of the pearlite is too fast, and when the content of the manganese (Mn) is 0.9% or more, low temperature tissue may be generated by segregation of manganese. There is a concern and because the delay of the ferrite transformation is too delayed, the transformation is not completely completed in the air-cooling zone of the wire rod factory, and the operation efficiency is lowered. Therefore, the content of the manganese is preferably limited to 0.6 to 0.9%.
상기 크롬(Cr)은 페라이트에 고용되기도 하고, 또한, 카바이드를 생성하는 시멘타이트(Fe3C)에 고용되어 시멘타이트의 강도를 증가시키며, 또한, 퍼얼라이트 변태시간을 지연시켜서 대경선재에서도 미세한 퍼얼라이트 조직을 얻을 수 있도록 하는 원소이다.The chromium (Cr) is also dissolved in ferrite, and is also dissolved in cementite (Fe 3 C) to form carbides to increase the strength of cementite, and also delay the perlite transformation time, and thus fine perlite structure in large diameter wire rods. Is an element that allows
상기 크롬의 함량이 0.2% 이하인 경우에는 대경선재의 냉각능 향상효과가 떨어지고, 0.5% 이상인 경우에는 중심편석 및 냉각능의 과도한 향상으로 인하여 오히려 저온조직이 발생될 염려가 있고, 또한 퍼얼라이트 변태시간이 너무 길어 실용적이지 못하므로, 상기 크롬의 함량은 0.2∼0.5%로 제한하는 것이 바람직하다.When the content of chromium is 0.2% or less, the effect of improving the cooling performance of the large diameter wire is inferior, and when it is 0.5% or more, the low temperature tissue may be generated due to excessive improvement of the central segregation and cooling capacity, and also the transition time of the pearlite. Since this is too long and not practical, the content of chromium is preferably limited to 0.2 to 0.5%.
상기 알루미늄(Al)은 탈산, 결정입도 미세화 및 인성개선을 위해 첨가되는 원소로서, 그 첨가량이 0.02% 이하인 경우에는 첨가효과가 없고, 0.1% 이상인 경우에는 AIN의 결정입계석출에 의한 취화의 가능성이 있을 뿐만 아니라 A12O3상태의 기재물로 존재하여 신선성을 나쁘게 하므로, 상기 알루미늄의 함량은 0.02∼0.1%로 제한하는 것이 바람직하다.The aluminum (Al) is an element added for deoxidation, grain size refinement, and toughness improvement. If aluminum is less than 0.02%, there is no additive effect, and if it is 0.1% or more, there is a possibility of embrittlement due to grain boundary precipitation of AIN. In addition to being present as a substrate in the A1 2 O 3 state, the freshness is bad, it is preferable to limit the content of aluminum to 0.02 to 0.1%.
상기 바나듐(V)은 미량으로도 냉각능을 향상시켜 퍼얼라이트 변태를 지연시키므로 대경선재에서도 미세한 퍼얼라이트 조직을 얻을 수 있다.The vanadium (V) improves the cooling ability even in a small amount to delay the perlite transformation, so that even a large diameter wire can obtain a fine perlite structure.
상기 바나듐은 0.07% 정도의 농도에서 최대의 냉각능 향상효과를 나타내고, 또 고용바나듐은 신선가공후의 블루잉(bluing) 처리시에 자유질소를 고정시켜 응력이완을 줄일 수 있다.The vanadium exhibits the greatest cooling ability improvement effect at a concentration of about 0.07%, and the vanadium solid solution can reduce the stress relaxation by fixing free nitrogen during the bluing treatment after the fresh processing.
상기 바나듐이 0.1% 이상인 경우에는 바나듐의 탄질화물의 석출에 의하여 바나듐의 냉각능 향상효과가 오히려 떨어지게 된다. 따라서, 상기 바나듐의 함량은 0.01∼0.1%로 제한하는 것이 바람직하다.When the vanadium is 0.1% or more, the effect of improving the cooling ability of vanadium is deteriorated by the precipitation of carbonitride of vanadium. Therefore, the content of the vanadium is preferably limited to 0.01 to 0.1%.
상기 질소의 함량이 높은 경우에는 신선가공시의 변형 및 가공열에 의해 발생되는 과시효에 의해 신선재가 취화될 염려가 있고, 또한 PC(Prestressed Concrete)강선인 경우에 응력이완(stress relaxation)의 정도가 크게 되므로, 상기 질소의 함량은 60ppm 이하로 제한하는 것이 바람직하다.When the content of nitrogen is high, there is a fear that the wire rod may be embrittled by overaging due to deformation and heat of processing during drawing, and the degree of stress relaxation in the case of PC (Prestressed Concrete) steel wire is high. Since it becomes large, it is preferable to limit the content of nitrogen to 60 ppm or less.
상기와 같이 조성되는 강재를 열간압연하게 되는데, 이때, 열간마무리압연온도(사상압연온도)가 1,000℃이하인 경우에는 오스테나이트 결정립이 너무 미세하여 연속냉각곡선이 고온, 단시간축으로 이동하기 때문에 그만큼 급냉시켜야 하므로 대경선재에서 미세한 퍼얼라이트 조직을 얻을 수 없고, 1,100℃ 이상인 경우에는 코일상태로 권취하는 온도까지 급냉시키는 것이 곤란하므로, 상기 열간마무리압연온도는 1,000∼ 1,100℃로 제한하는 것이 바람직하다.The steel material formed as described above is hot rolled. At this time, when the hot finishing rolling temperature (delay rolling temperature) is 1,000 ° C. or less, the austenite grains are too fine and the continuous cooling curve is moved to a high temperature and a short time axis, thereby rapidly cooling. Since the fine pearlite structure cannot be obtained from the large diameter wire rod, and if it is 1,100 ° C or more, it is difficult to quench it to a temperature wound in a coil state, and therefore, the hot finish rolling temperature is preferably limited to 1,000 to 1,100 ° C.
상기 권취온도가 850℃ 이상인 경우에는 강제공냉으로 퍼얼라이트 변태직전까지 4℃/sec의 냉각속도로 냉각시키는 것이 어려우며, 780℃ 이하인 경우에는 코일의 형상이 불균일해지기 때문에 상기 권취온도는 780∼850℃로 제한하는 것이 바람직하다.When the coiling temperature is 850 ° C or higher, it is difficult to cool by forced air cooling at a cooling rate of 4 ° C / sec until just before the transformation of the pearlite. When the coiling temperature is 780 ° C or lower, the coil shape becomes uneven, so the coiling temperature is 780 to 850. It is preferable to limit to ℃.
강제공냉시 상기 냉각속도가 4℃/sec 이하인 경우에는 냉각속도가 너무 느려 초석 시멘타이트의 발생과 조대한 퍼얼라이트 조직이 되기 쉽고, 냉각속도가 10℃/sec 이상인 경우에는 냉각속도가 너무 빠르게 되어 선재중심부에 저온조직이 발생될 염려가 있기 때문에, 강제공냉시 냉각속도는 4∼10℃/sec로 제한하는 것이 바람직하다.During forced air cooling, if the cooling rate is 4 ° C / sec or less, the cooling rate is too slow to form the cornerstone cementite and coarse pearlite structure, and if the cooling rate is 10 ° C / sec or more, the cooling rate is too fast. Since there is a possibility that low-temperature tissue is generated in the center, it is preferable to limit the cooling rate during forced air cooling to 4 to 10 ° C / sec.
이하, 실시예를 통하여 본 발명을 보다 상세히 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.
[실시예]EXAMPLE
하기표 1과 같이 조성되는 빌렛(billet)(160×160mm)을, 1,050℃ 가열로에서 약 1.5시간 가열후 1,000℃로 추출하였다. 1,000∼1,100℃로 사상압연한후 직선상태에서 800℃까지 분무된 냉각수로 수냉하였다. 800℃까지 수냉된 직선상의 선재는 코일상의 선재로 권취한 다음에 550℃까지 4℃/sec의 냉각속도로 강제공냉하여 대경선재(시편)을 제조하였다.The billet (160 × 160 mm), which is formed as shown in Table 1, was extracted at 1,000 ° C. after heating at 1,050 ° C. for about 1.5 hours. After rolling at 1,000 to 1,100 ° C., the mixture was cooled with water sprayed to 800 ° C. in a linear state. The wire rod, which was cooled to 800 ° C., was wound with coiled wire rod, and then forcedly air-cooled at a cooling rate of 4 ° C./sec to 550 ° C. to prepare a large diameter wire rod (sample).
상기와 같이 제조된 각 시편에 대하여 인장시험을 행하여 인장강도 및 단면감소율을 측정하고, 그 결과를 하기표 2에 나타내었다. 또한, 비교재 A 및 발명재 F에 대한 조직사진을 관찰하고, 그 결과를 제1도에 나타내었다.Tensile tests were performed on the specimens prepared as described above, and tensile strength and cross-sectional reduction rate were measured, and the results are shown in Table 2 below. In addition, the photographs of tissues of Comparative Material A and Inventive Material F were observed, and the results are shown in FIG.
[표 1]TABLE 1
[표 2]TABLE 2
* C : 중심(Center), E : 가장자리(Edge), R : 중심과 가장자리의 중간부* C: Center, E: Edge, R: Center and Middle
상기표 2에 나타난 바와 같이, 본 발명재(F)는 비교재(A-E)보다 인장강도 및 단면감소율에 있어 우수함을 알 수 있다.As shown in Table 2, it can be seen that the present invention material (F) is superior in tensile strength and cross-sectional reduction rate than the comparative material (A-E).
한편, 제1도에 나타난 바와 같이, 비교재 A「제1도의 (a)」의 경우에는 대경선재의 중심부에 초석 시멘타이트가 발생됨에 반하여, 본 발명재 F「제1도의 (b)」의 경우에는 초석 시멘타이트가 발생되지 않음을 알 수 있다.On the other hand, as shown in FIG. 1, in the case of the comparative material A "(a) of FIG. 1", the cornerstone cementite is generated in the center of a large diameter wire, whereas in the case of this invention material F "(b) of FIG. It can be seen that the cornerstone cementite does not occur.
상술한 바와 같이, 본 발명은 초석 시멘타이트가 발생되지 않으므로서 신선가공성이 우수하고, 응력이완성(stress relaxation)이 작은 고탄소의 고강도, 고연성 압연선재를 제공할 수 있는 효과가 있는 것이다.As described above, the present invention has an effect of providing a high-carbon, high-strength, high-ductility rolled wire having excellent drawability and low stress relaxation without generating cornerstone cementite.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019930010994A KR950007785B1 (en) | 1993-06-16 | 1993-06-16 | Making method of high tension wire rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019930010994A KR950007785B1 (en) | 1993-06-16 | 1993-06-16 | Making method of high tension wire rod |
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| Publication Number | Publication Date |
|---|---|
| KR950000907A KR950000907A (en) | 1995-01-03 |
| KR950007785B1 true KR950007785B1 (en) | 1995-07-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| KR1019930010994A KR950007785B1 (en) | 1993-06-16 | 1993-06-16 | Making method of high tension wire rod |
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| KR (1) | KR950007785B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010123315A3 (en) * | 2009-04-23 | 2011-03-10 | 주식회사 포스코 | High strength, high toughness steel wire rod, and method for manufacturing same |
| CN110629132A (en) * | 2019-09-26 | 2019-12-31 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for ultra-high strength steel cord and method for producing same |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100238014B1 (en) * | 1995-12-26 | 2000-01-15 | 이구택 | The manufacturing method for wire rod used welding wire rod |
| KR100241303B1 (en) * | 1995-12-26 | 2000-03-02 | 이구택 | The manufacturing method for high carbon steel wire rod |
| KR100238013B1 (en) * | 1995-12-26 | 2000-01-15 | 이구택 | The manufacturing method for wire rod used suspension spring |
| KR100276298B1 (en) * | 1996-11-07 | 2000-12-15 | 이구택 | The manufacturing method of wire drawing used wire rod contained manganes |
| KR100398384B1 (en) * | 1998-12-16 | 2003-12-18 | 주식회사 포스코 | A method of manufacturing wire fod for presiressed concrete wire having superior strength and toughness |
| KR20040027003A (en) * | 2002-09-27 | 2004-04-01 | 주식회사 포스코 | A manufacturing method of steel for spring without ferrite decarburization |
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1993
- 1993-06-16 KR KR1019930010994A patent/KR950007785B1/en not_active IP Right Cessation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010123315A3 (en) * | 2009-04-23 | 2011-03-10 | 주식회사 포스코 | High strength, high toughness steel wire rod, and method for manufacturing same |
| RU2494165C2 (en) * | 2009-04-23 | 2013-09-27 | Поско | High-strength high-ductility steel rod and method of its production |
| CN110629132A (en) * | 2019-09-26 | 2019-12-31 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for ultra-high strength steel cord and method for producing same |
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| Publication number | Publication date |
|---|---|
| KR950000907A (en) | 1995-01-03 |
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