KR20120132829A - Method for manufacturing high-strength deformed bar with low yield ratio - Google Patents
Method for manufacturing high-strength deformed bar with low yield ratio Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 25
- 238000005096 rolling process Methods 0.000 claims abstract description 15
- 238000001816 cooling Methods 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 8
- 229910052802 copper Inorganic materials 0.000 claims abstract description 7
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 7
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 7
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 7
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 7
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 5
- 238000010791 quenching Methods 0.000 claims abstract description 4
- 230000000171 quenching effect Effects 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 18
- 239000002344 surface layer Substances 0.000 claims description 14
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 229910000831 Steel Inorganic materials 0.000 abstract description 9
- 239000010959 steel Substances 0.000 abstract description 9
- 238000005482 strain hardening Methods 0.000 abstract description 2
- 239000011572 manganese Substances 0.000 description 10
- 239000010949 copper Substances 0.000 description 8
- 230000001965 increasing effect Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 230000000704 physical effect Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000002787 reinforcement Effects 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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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
- C21D8/08—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires for concrete reinforcement
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- 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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- 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
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- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- 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
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
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Abstract
내진용 철근 및 그 제조방법에 관한 것으로, 보다 상세하게는 항복 이후에 충분한 가공경화능을 갖는 저항복비(인장강도/항복강도) 내진용 철근 및 그 제조방법에 관하여 개시한다.
본 발명은 중량%로 C:0.1~0.4%, Si: 0.1~0.6%, Mn: 0.4~1.5%, P: 0.01~0.03%, S: 0.01~0.03%, Cu: 0.01~0.3%, V:0.01~0.15% 및 나머지는 Fe 및 기타 불가피하게 함유되는 불순물로 이루어진 강재를 1000℃~1250℃의 온도범위로 가열하고, 철근압연공정을 통하여 950℃~1250℃에서의 압연종료 온도조건으로 열간압연한 후, 템프코어에서 급냉을 수행하되, 냉각시의 열전달계수가 23000~38000W/m2K 가 되도록 하는 것을 특징으로 하는 저항복비 내진용 철근 제조방법을 제공한다.The present invention relates to a seismic reinforcing bar and a method of manufacturing the same, and more particularly, to a resistance yield ratio (tensile strength / yield strength) of a seismic reinforcing bar having sufficient work hardening ability after yielding and a method of manufacturing the same.
In the present invention, C: 0.1 to 0.4%, Si: 0.1 to 0.6%, Mn: 0.4 to 1.5%, P: 0.01 to 0.03%, S: 0.01 to 0.03%, Cu: 0.01 to 0.3%, and V: 0.01 ~ 0.15% and the remainder are heated to 1000 ℃ ~ 1250 ℃ temperature steel, consisting of Fe and other inevitable impurities, and hot-rolled at the end temperature of rolling at 950 ℃ ~ 1250 ℃ through rebar rolling process. After that, while performing quenching in the temp core, it provides a method for manufacturing a resistance to earthquake-resistant seismic reinforcing bar, characterized in that the heat transfer coefficient during cooling to be 23000 ~ 38000W / m 2 K.
Description
본 발명은 내진용 철근 및 그 제조방법에 관한 것으로, 보다 상세하게는 항복 이후에 충분한 가공경화능을 갖는 저항복비(인장강도/항복강도) 내진용 철근 및 그 제조방법에 관한 것이다.
The present invention relates to a seismic reinforcing bar and a method for manufacturing the same, and more particularly, to a resistance yield ratio (tensile strength / yield strength) seismic reinforcing bar having a sufficient work hardening ability after yielding.
일반적으로 고장력 철근을 제조하기 위해서는 템프코어(Tempcore)를 이용하고 있다. 템프코어를 이용하면 제조되는 철근의 표면이 급냉으로 인하여 마르텐사이트 조직을 갖게 됨으로써 높은 항복강도를 나타낸다.Generally, Tempcore is used to manufacture high tensile rebar. When using the temp core, the surface of the reinforcing steel bar produced has a martensite structure due to quenching, thereby showing high yield strength.
따라서, 템프코어를 사용하여 저항복비를 갖는 고장력 철근을 생산하기에는 어려움이 있었다.
Therefore, it was difficult to produce high tensile reinforcing bars having a resistive ratio using the temp core.
본 발명의 목적은 템프코어 공정을 사용하여 철근을 제조하되 표면 경화층의 분율을 제어함으로써 항복강도 600MPa 이상의 고강도와 더불어 1.25 이상의 낮은 항복비(인장강도/항복강도)를 갖는 내진용 철근 및 그 제조방법을 제공함에 있다.
An object of the present invention is to manufacture steel reinforcement using the temp core process, but to control the fraction of the surface hardened layer, seismic reinforcing steel having a high yield strength of 600 MPa or more and a low yield ratio (tensile strength / yield strength) of 1.25 or more, and its manufacture In providing a method.
본 발명은 중량%로 C:0.1~0.4%, Si: 0.1~0.6%, Mn: 0.4~1.5%, P: 0.01~0.03%, S: 0.01~0.03%, Cu: 0.01~0.3%, V:0.01~0.15% 및 나머지는 Fe 및 기타 불가피하게 함유되는 불순물로 이루어진 강재를 1000℃~1250℃의 온도범위로 가열하고, 철근압연공정을 통하여 950℃~1250℃에서의 압연종료 온도조건으로 열간압연한 후, 템프코어에서 급냉을 수행하되, 냉각시의 열전달계수가 23000~38000W/m2K 가 되도록 하는 것을 특징으로 하는 저항복비 내진용 철근 제조방법을 제공한다.In the present invention, C: 0.1 to 0.4%, Si: 0.1 to 0.6%, Mn: 0.4 to 1.5%, P: 0.01 to 0.03%, S: 0.01 to 0.03%, Cu: 0.01 to 0.3%, and V: 0.01 ~ 0.15% and the remainder are heated to 1000 ℃ ~ 1250 ℃ temperature steel, consisting of Fe and other inevitable impurities, and hot-rolled at the end temperature of rolling at 950 ℃ ~ 1250 ℃ through rebar rolling process. After that, while performing quenching in the temp core, it provides a method for manufacturing a resistance to earthquake-resistant seismic reinforcing bar, characterized in that the heat transfer coefficient during cooling to be 23000 ~ 38000W / m 2 K.
이 때, 상기 템프코어의 공정조건은 공급유량이 312~416m3/h 범위인 것이 바람직하다.
At this time, the process conditions of the temp core is preferably a supply flow rate of 312 ~ 416m 3 / h range.
또한, 본 발명은 상기의 방법으로 제조되어, 경화층인 표면층의 분율이 19~29% 범위인 것을 특징으로 하는 저항복비 내진용 철근을 제공한다.In addition, the present invention is produced by the above method, the fraction of the surface layer which is a hardened layer provides a resistance-to-earthquake-resistant reinforcing bar, characterized in that the range.
이 때,상기 저항복비 내진용 철근은, 내부층의 경도가 210Hv 이상이고, 항복강도 600MPa 이상, 항복비(항복강도/인장강도) 0.8 이하인 물성을 나타낸다.
At this time, the resistance yield ratio seismic reinforcing bar, the hardness of the inner layer is 210Hv or more, yield strength 600MPa or more, yield ratio (yield strength / tensile strength) 0.8 or less.
본 발명은 템프코어를 이용하여 600MPa 이상의 항복강도와 0.8 이하의 저항복비(항복강도/인장강도)를 가지는 내진용 철근을 제조할 수 있는 효과를 가져온다.The present invention has the effect of producing a seismic reinforcing bar having a yield strength of 600MPa or more and a resistance yield ratio of 0.8 or less (yield strength / tensile strength) using the temp core.
이러한 방법으로 제조된 내진용 철근은 에너지를 효과적으로 흡수함으로써, 이를 이용하여 축조되는 건축물이나 구조물의 내진성능을 향상시키는 효과를 가져온다.
The seismic reinforcing bar manufactured in this way effectively absorbs energy, thereby bringing the effect of improving the seismic performance of the building or structure constructed using it.
도 1은 본 발명의 실시예에 따른 내진용 철근의 냉각시 열전달 계수와 경화층인 표면층의 분율과의 관계를 나타낸 그래프이다.1 is a graph showing the relationship between the heat transfer coefficient of the seismic reinforcing bar according to the embodiment of the present invention and the fraction of the surface layer which is a hardened layer.
본 발명의 이점 및 특징, 그리고 그것들을 달성하는 방법은 첨부되는 도면과 함께 상세하게 후술되어 있는 실시예들을 참조하면 명확해질 것이다. 그러나, 본 발명은 이하에서 개시되는 실시예들에 한정되는 것이 아니라 서로 다른 다양한 형태로 구현될 것이며, 단지 본 실시예들은 본 발명의 개시가 완전하도록 하며, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이며, 본 발명은 청구항의 범주에 의해 정의될 뿐이다. 명세서 전체에 걸쳐 동일 참조 부호는 동일 구성요소를 지칭한다.
BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.
이하 첨부된 도면을 참조하여 본 발명의 바람직한 실시예에 따른 템프코어를 이용한 저항복비 내진용 철근 및 그 제조방법에 관하여 상세히 설명하면 다음과 같다.
Hereinafter, with reference to the accompanying drawings, a detailed description will be given of a resistance-to-wear ratio seismic reinforcing bar using a temper core according to a preferred embodiment of the present invention and a manufacturing method thereof.
본 발명은 중량%로 C:0.1~0.4%, Si: 0.1~0.6%, Mn: 0.4~1.5%, P: 0.01~0.03%, S: 0.01~0.03%, Cu: 0.01~0.3%, V:0.01~0.15% 및 나머지는 Fe 및 기타 불가피하게 함유되는 불순물로 이루어진 강재를 1000℃~1250℃의 온도범위로 가열하고, 철근압연공정을 통하여 950℃~1250℃에서의 압연종료 온도조건으로 열간압연한 후, 템프코어에서 냉각시의 열전달계수가 23000~38000W/m2K 범위에서 열처리 되어, 경화층인 표면층의 분율이 19~29% 범위인 것을 특징으로 하는 저항복비 내진용 철근을 제공한다.In the present invention, C: 0.1 to 0.4%, Si: 0.1 to 0.6%, Mn: 0.4 to 1.5%, P: 0.01 to 0.03%, S: 0.01 to 0.03%, Cu: 0.01 to 0.3%, and V: 0.01 ~ 0.15% and the remainder are heated to 1000 ℃ ~ 1250 ℃ temperature steel, consisting of Fe and other inevitable impurities, and hot-rolled at the end temperature of rolling at 950 ℃ ~ 1250 ℃ through rebar rolling process. After that, the heat transfer coefficient during cooling in the temp core is heat treated in the range of 23000 ~ 38000W / m 2 K, to provide a resistive ratio seismic reinforcing steel bar, characterized in that the fraction of the surface layer of the cured layer is in the range of 19 ~ 29%.
이 때, 저항복비 내진용 철근은, 내부층의 경도가 210Hv 이상, 항복강도 600MPa 이상, 항복비(항복강도/인장강도) 0.8 이하의 물성을 나타낸다.
At this time, the resistive-ratio seismic reinforcing bars exhibit physical properties of the hardness of the inner layer of 210 Hv or more, yield strength of 600 MPa or more, and yield ratio (yield strength / tensile strength) of 0.8 or less.
본 발명은 합금조성으로부터 내부층의 경도를 확보하고, 템프코어 공정의 냉각조건을 제어함으로써, 내부층과 표면층의 분율을 제어함으로써, 항복강도 600MPa 이상, 항복비 0.8 이하의 물성을 가지는 내진용 철근을 제공한다.
The present invention is to secure the hardness of the inner layer from the alloy composition, and to control the cooling conditions of the temp core process, to control the fraction of the inner layer and the surface layer, the seismic reinforcing steel having a physical property of yield strength 600MPa or more, yield ratio 0.8 or less To provide.
내진용 철근Seismic rebar
본 발명에 따른 내진용 철근은 항복강도 600MPa 이상, 항복비 강 조성을 조절하되, 특히 Zr의 함량을 제어함으로써 고온결정립을 조대화하여 항복비를 낮추는 것을 특징으로 한다.The seismic reinforcing steel according to the present invention is characterized by lowering the yield ratio by coordinating high temperature grains by controlling the yield strength of 600MPa or more, yield ratio steel composition, in particular by controlling the content of Zr.
본 발명에 따른 내진용 철근은 항복강도 600MPa 이상, 0.8 이하의 저항복비(항복강도/인장강도)의 기계적 물성을 나타내기 위하여 하기와 같은 조성을 가진다.
The seismic reinforcing bar according to the present invention has a composition as follows to indicate the mechanical properties of the yield strength (yield strength / tensile strength) of more than 600MPa, 0.8 or less yield strength.
본 발명에 따른 내진용 철근은 중량%로 탄소(C) : 0.10~0.40%, 실리콘(Si) : 0.10~0.60%, 망간(Mn) : 0.40~1.50%, 인(P) : 0.03% 이하, 황(S) : 0.03% 이하, 구리(Cu) : 0.30% 이하, 바나듐(V) : 0.015% 이하 및 나머지 Fe와 불가피한 불순물을 포함한다.
Seismic reinforcing bar according to the present invention by weight% carbon (C): 0.10 ~ 0.40%, silicon (Si): 0.10 ~ 0.60%, manganese (Mn): 0.40 ~ 1.50%, phosphorus (P): 0.03% or less, Sulfur (S): 0.03% or less, copper (Cu): 0.30% or less, vanadium (V): 0.015% or less and the remaining Fe and inevitable impurities.
이하, 본 발명에 따른 내진용 철근에 포함되는 각 성분의 역할 및 그 함량에 대하여 설명하면 다음과 같다.
Hereinafter, the role and content of each component included in the seismic reinforcing bar according to the present invention will be described.
탄소(C)Carbon (C)
C는 강도상승에 유효한 원소이다. 그러나 함유량이 0.10% 미만이면 원하는 고강도가 얻어지지 않는다. 더욱이, 0.4%를 넘으면 강도증가에는 유효하지만 인성 및 연성의 열화가 현저하므로, 0.4% 이하로 지정하여 첨가하는 것이 필요하다. 따라서, C의 함유량은 0.10%~0.4%의 범위로 첨가하는 것이 필요하다.
C is an element effective for increasing the strength. However, if the content is less than 0.10%, the desired high strength will not be obtained. Moreover, if it exceeds 0.4%, it is effective for increasing the strength, but deterioration of toughness and ductility is remarkable, so it is necessary to designate it at 0.4% or less and add it. Therefore, it is necessary to add C content in 0.10%-0.4% of range.
실리콘(Si)Silicon (Si)
Si는 철강의 탈산에 필수적인 원소이며, 강도상승에 효과가 있는 원소이다. 그러나 함유량이 0.1% 이하이면 원하는 고강도가 얻어지지 않는다. 더욱이, 0.6%를 넘으면 인성 및 연성의 급격한 저하를 초래한다. 따라서, Si의 함유량은 0.1%~0.6%의 범위로 첨가하는 것이 필요하다.
Si is an essential element for deoxidation of steel and is an element effective in increasing the strength. However, if the content is 0.1% or less, the desired high strength will not be obtained. Moreover, exceeding 0.6% causes a sharp decrease in toughness and ductility. Therefore, it is necessary to add content of Si in 0.1%-0.6% of range.
망간(Mn)Manganese (Mn)
Mn은 소입성을 향상시킴에 의해 열처리 시에 강도를 상승시키는 효과가 있다. 특히, 전술한 바와 같은 C의 첨가량 제한에 따른 강도보상을 위해 필수적으로 첨가되는 원소이기도 하다. 여기서, 상기 Mn은 첨가량이 0.4% 이하이면 소입성 향상효과가 거의 없고 1.5%를 넘으면 용접성이 저하되며, 균열발생의 위험성이 높아진다. 따라서, Mn의 첨가량은 0.4%~1.5%의 범위로 첨가하는 것이 바람직하다.
Mn has the effect of increasing the strength during heat treatment by improving the hardenability. In particular, it is also an element that is added essentially for strength compensation according to the addition amount of C as described above. In this case, when Mn is added in an amount of 0.4% or less, there is little effect of improving hardening property, and when Mn exceeds 1.5%, weldability is lowered and the risk of cracking is increased. Therefore, it is preferable to add Mn addition amount in 0.4%-1.5% of range.
인(P)Phosphorus (P)
P는 강재의 충격 인성을 저해하는 불순물로서, 연주시 중심편석부에 집적하여 내부품질 및 가공성을 해치고, 수소 취화의 원인이 되기 때문에 최소한으로 억제하는 것이 좋다. 따라서, 제강 설비 능력을 고려하게 되면 0.03% 이하로 제한하는 것이 바람직하다.
P is an impurity that impairs the impact toughness of the steel material, and it is preferable to minimize it because it accumulates in the central segregation portion during performance, impairs internal quality and workability, and causes hydrogen embrittlement. Therefore, considering the steelmaking facility capability, it is desirable to limit the content to 0.03% or less.
황(S)Sulfur (S)
S는 상기 P와 동일하게 연성 및 충격 인성에 유해한 원소로서, 연속주조시 고온 균열과 중심 편석을 유발한다.S, like P, is an element harmful to ductility and impact toughness and causes hot cracking and central segregation during continuous casting.
또한, MnS 등의 개재물로 형성되어 내부품질 불량의 원인이 되기 때문에 그 함유량을 0.03% 이하로 제한하는 것이 바람직하다.
Moreover, since it forms with inclusions, such as MnS, and becomes a cause of poor internal quality, it is preferable to limit the content to 0.03% or less.
구리(Cu)Copper (Cu)
Cu는 제강원료인 철 스크랩에 불가피하게 함유되는 원소로서, 석출강화효과에 의해 강도를 상승시키지만, 많이 첨가되면 표면결함을 유발시키므로 그 첨가량을 0.5% 이하로 제한한다.
Cu is an element that is inevitably contained in steel scrap, which is a steelmaking raw material, and the strength is increased by the precipitation strengthening effect. However, Cu is used to cause surface defects, so the amount thereof is limited to 0.5% or less.
바나듐(V)Vanadium (V)
V는 고온에서 C 또는 N과 화학결합하여, V(C,N)인 석출물을 형성하게 되며, 그로 인해 석출강화 효과를 유발한다. 그러나, 함유량이 0.15%를 넘으면 강도가 높아지는 정도가 작아져서 그 효과가 줄어들며, 더욱이 항복강도를 집중적으로 증가시킴에 의해 항복비를 높이게 된다.V chemically bonds with C or N at high temperatures to form precipitates that are V (C, N), thereby inducing a precipitation strengthening effect. However, when the content exceeds 0.15%, the degree of increase in strength decreases, and the effect is reduced, and the yield ratio is increased by intensively increasing the yield strength.
이외에도 V의 첨가는 충격인성을 저하시키므로, V의 적정 첨가량은 0.15% 이하로 제한한다.
In addition, since the addition of V lowers the impact toughness, an appropriate amount of V is limited to 0.15% or less.
템프코어를 이용한 철근 제조방법Rebar manufacturing method using temp core
상술한 바와 같은 합금원소들이 각각의 중량비 범위 내에서 첨가되고, 나머지는 Fe 및 불가피하게 함유되는 불순물로 조성된 강재를 전기로에서 제조한 후, 연속주조에 의해 빌렛(billet)으로 만든다.The alloying elements as described above are added within the respective weight ratio ranges, and the remainder is billed by continuous casting after the steel material composed of Fe and inevitably contained impurities is produced in an electric furnace.
이후, 주조된 빌렛(billet)을 가열로에서 1000℃~1250℃의 온도범위로 재가열하여 추출한 후, 통상의 철근압연공정에 따라서 열간압연을 실시한다.Thereafter, the cast billet is reheated and extracted in a heating range of 1000 ° C. to 1250 ° C. in a heating furnace, followed by hot rolling in accordance with a conventional rebar rolling process.
이때, 열간압연조건은 특별히 제약조건은 없으나, 압연롤의 부하 및 생산성 등을 고려할 때, 가능한 높은 온도에서 압연을 종료하는 것이 좋으므로, 압연종료온도를 950℃ 이상의 온도조건으로 적용시키는 것이 바람직하다.At this time, the hot rolling conditions are not particularly limited, but considering the load and productivity of the rolling roll, it is preferable to finish the rolling at the highest possible temperature, so that the end rolling temperature is preferably applied at a temperature of 950 ° C. or higher. .
상기와 같이, 압연종료온도가 높으면 최종적인 철근제품의 결정립 크기는 상대적으로 조대해지며, 이는 결정립이 미세한 경우보다도 항복비를 낮추는 데에 있어서 유리하게 된다.As described above, when the end temperature of the rolling is high, the grain size of the final reinforcement product is relatively coarse, which is advantageous in lowering the yield ratio than when the grain is fine.
한편, 열간압연이 끝난 철근들은 템프코어(Tempcore)에 통과시켜서 열처리를 실시하게 되며, 이때 수냉조 내의 냉각조건, 즉 열전달량과 복열온도를 소정의 범위 내에서 조절한다.On the other hand, the hot rolled reinforcing bars are subjected to a heat treatment by passing through the Tempcore (Tempcore), at this time to control the cooling conditions in the water cooling tank, that is, the heat transfer amount and the recuperation temperature within a predetermined range.
이와 같이, 소정의 범위 내에서 냉각조건을 조절함으로써 내부와 표면의 경도 및 경화층의 분율을 제어할 수 있고, 이로부터 요구하는 물성인 저항복비를 만족시킬 수 있다.
In this way, by controlling the cooling conditions within a predetermined range, the hardness of the inside and the surface and the fraction of the hardened layer can be controlled, thereby satisfying the resistive ratio, which is the required physical properties.
도 1은 본 발명의 실시예에 따른 내진용 철근의 냉각시 열전달 계수와 경화층인 표면층의 분율과의 관계를 나타낸 그래프이다.1 is a graph showing the relationship between the heat transfer coefficient of the seismic reinforcing bar according to the embodiment of the present invention and the fraction of the surface layer which is a hardened layer.
도 1을 참조하면, 열전달계수가 높을수록 표면층의 분율은 증가하고, 열전달계수가 낮을 수록 표면층의 분율이 감소하는 것을 알 수 있다.Referring to FIG. 1, the higher the heat transfer coefficient, the higher the fraction of the surface layer, and the lower the heat transfer coefficient, the lower the fraction of the surface layer.
내부층과 표면층은 서로 상이한 물성을 가지게 되므로, 표면층과 경화층의 분율을 조절하는 방법으로, 전체 내진용 철근의 물성을 제어할 수 있게 된다.Since the inner layer and the surface layer have different physical properties from each other, it is possible to control the physical properties of the entire earthquake-resistant rebar by adjusting the fraction of the surface layer and the hardened layer.
도 1에서 알 수 있듯이, 내부층과 표면층의 분율 제어는 템프코어 공정에서 냉각시의 열전달계수에 따라 달라지는데, 이러한 열전달계수는 템프코어에 공급되는 유량과 직접적으로 관련이 있다.As can be seen in Figure 1, the control of the fraction of the inner layer and the surface layer is dependent on the heat transfer coefficient during cooling in the temp core process, this heat transfer coefficient is directly related to the flow rate supplied to the temp core.
본 발명은 수차례의 반복실험결과 경화층 분율이 19~29% 범위를 가지는 경우, 요구하는 항복강도와 항복비를 만족시킬 수 있다는 결과를 도출하였다.According to the present invention, several times of repeated experiments, when the cured layer fraction is in the range of 19-29%, the required yield strength and yield ratio can be satisfied.
경화층 분율이 19~29% 범위가 되기 위한 열전달 계수는, 도 1의 그래프로부터 23000~38000W/m2K 범위가 된다.The heat transfer coefficient for the hardened layer fraction to be in the range of 19 to 29% is in the range of 23000 to 38000 W / m 2 K from the graph of FIG. 1.
열전달 계수와 유량의 관계는 하기의 수학식 1과 같다.
The relationship between the heat transfer coefficient and the flow rate is shown in Equation 1 below.
상기의 수학식 1로부터 열전달 계수 : 23000~38000W/m2K 를 만족하는 유량범위를 312~416m3/h 를 도출하였다.The heat flow coefficient satisfying heat transfer coefficient: 23000-38000 W / m 2 K was derived from Equation 1 above, 312 to 416 m 3 / h.
하기의 표 1은 템프코어의 공정조건과 합금성분을 나타낸 것이고, 표 2는 각각의 공정조건에서 경도와, 분율 및 기계적 특성 결과치를 나타낸 것이다.
Table 1 below shows the process conditions and alloy components of the temp core, Table 2 shows the hardness, fractions and mechanical properties results at each process condition.
표 2의 결과를 살펴보면, 유량의 범위가 312~416m3/h 를 만족하는 경우, 표면층 분율이 19~29% 범위를 만족하게 되며, 항복강도 600MPa 이상, 항복비 0.8 이하를 모두 만족하는 것을 알 수 있다.Looking at the results of Table 2, it is found that when the flow rate ranges from 312 to 416 m 3 / h, the surface layer fraction satisfies the range of 19 to 29%, and satisfies both the yield strength of 600 MPa or more and the yield ratio of 0.8 or less. Can be.
유량이 상기 범위를 초과하게 되면 표면층의 분율이 증가하여 항복강도가 저하되며, 항복비는 커지게 되고,When the flow rate exceeds the above range, the fraction of the surface layer increases, the yield strength decreases, and the yield ratio becomes large,
유량이 상기 범위 미만이되면, 경화층인 표면층의 분율을 확보하지 못하여 요구하는 항복강도를 얻을 수 없다.When the flow rate is less than the above range, the fraction of the surface layer, which is a cured layer, cannot be secured, so that the required yield strength cannot be obtained.
이상에서는 본 발명의 실시예를 중심으로 설명하였지만, 당업자의 수준에서 다양한 변경이나 변형을 가할 수 있다. 이러한 변경과 변형이 본 발명의 범위를 벗어나지 않는 한 본 발명에 속한다고 할 수 있다. 따라서 본 발명의 권리범위는 이하에 기재되는 청구범위에 의해 판단되어야 할 것이다.While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications may belong to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention will be determined by the claims described below.
Claims (5)
템프코어에서 급냉을 수행하되, 냉각시의 열전달계수가 23000~38000W/m2K 가 되도록 하는 것을 특징으로 하는 저항복비 내진용 철근 제조방법.
By weight% C: 0.1 ~ 0.4%, Si: 0.1 ~ 0.6%, Mn: 0.4 ~ 1.5%, P: 0.01 ~ 0.03%, S: 0.01 ~ 0.03%, Cu: 0.01 ~ 0.3%, V: 0.01 ~ 0.15 % And the remainder are heated to a temperature range of 1000 ℃ to 1250 ℃ consisting of Fe and other unavoidable impurities, and hot rolled to a rolling end temperature condition of 950 ℃ ~ 1250 ℃ through a reinforcing rolling process,
A method for manufacturing a resistance to earthquake-resistant seismic reinforcing bar, characterized in that quenching is performed on the temper core, but the heat transfer coefficient during cooling is 23000 to 38000 W / m 2 K.
상기 템프코어의 공정조건은
공급유량이 312~416m3/h 범위인 것을 특징으로 하는 저항복비 내진용 철근 제조방법.
The method of claim 1,
Process conditions of the temp core
Resistant-ratio earthquake-resistant rebar manufacturing method, characterized in that the supply flow rate is 312 ~ 416m 3 / h range.
템프코어에서 냉각시의 열전달계수가 23000~38000W/m2K 범위에서 열처리 되어, 경화층인 표면층의 분율이 19~29% 범위인 것을 특징으로 하는 저항복비 내진용 철근.
By weight% C: 0.1 ~ 0.4%, Si: 0.1 ~ 0.6%, Mn: 0.4 ~ 1.5%, P: 0.01 ~ 0.03%, S: 0.01 ~ 0.03%, Cu: 0.01 ~ 0.3%, V: 0.01 ~ 0.15 % And the remainder are heated to a temperature range of 1000 ℃ to 1250 ℃ consisting of Fe and other unavoidable impurities, and hot rolled to a rolling end temperature condition of 950 ℃ ~ 1250 ℃ through a reinforcing rolling process,
Heat-resistance coefficient during cooling in the temp core is heat-treated in the range of 23000 ~ 38000W / m 2 K, the fraction of the surface layer of the hardened layer is characterized in that the range of 19 ~ 29% resistance earthquake-resistant seismic reinforcing steel.
상기 저항복비 내진용 철근은,
내부층의 경도가 210Hv 이상인 것을 특징으로 하는 저항복비 내진용 철근.
The method of claim 3, wherein
The resistance ratio of the seismic reinforcing bar,
Resistant-ratio seismic reinforcing bars, characterized in that the hardness of the inner layer is 210Hv or more.
상기 저항복비 내진용 철근은
항복강도 600MPa 이상, 항복비(항복강도/인장강도) 0.8 이하인 것을 특징으로 하는 저항복비 내진용 철근.The method of claim 3, wherein
The resistive ratio seismic rebar is
A yield strength seismic reinforcing bar, characterized in that the yield strength 600MPa or more, the yield ratio (yield strength / tensile strength) 0.8 or less.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105483544A (en) * | 2015-12-21 | 2016-04-13 | 马鞍山钢铁股份有限公司 | 500MPa anti-seismic coiled thread steel and processing method thereof |
| KR20170113784A (en) * | 2016-03-25 | 2017-10-13 | 주식회사 포스코 | Reinforcement material and reinforced concrete pillar having thereof |
| WO2018074887A1 (en) * | 2016-10-21 | 2018-04-26 | 현대제철 주식회사 | High-strength reinforcing steel and method for manufacturing same |
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| CN105483544A (en) * | 2015-12-21 | 2016-04-13 | 马鞍山钢铁股份有限公司 | 500MPa anti-seismic coiled thread steel and processing method thereof |
| KR20170113784A (en) * | 2016-03-25 | 2017-10-13 | 주식회사 포스코 | Reinforcement material and reinforced concrete pillar having thereof |
| WO2018074887A1 (en) * | 2016-10-21 | 2018-04-26 | 현대제철 주식회사 | High-strength reinforcing steel and method for manufacturing same |
| CN109843456A (en) * | 2016-10-21 | 2019-06-04 | 现代制铁株式会社 | High intensity enhancing steel and its manufacturing method |
| GB2569933A (en) * | 2016-10-21 | 2019-07-03 | Hyundai Steel Co | High-strength reinforcing steel and method for manufacturing same |
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| GB2569933B (en) * | 2016-10-21 | 2022-10-19 | Hyundai Steel Co | High-strength reinforcing steel and method for manufacturing same |
| US11643697B2 (en) | 2016-10-21 | 2023-05-09 | Hyundai Steel Company | High-strength reinforcing steel and method for manufacturing same |
| KR102100059B1 (en) * | 2018-10-25 | 2020-04-10 | 현대제철 주식회사 | Steel reinforcement and method of manufacturing the same |
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