KR100355019B1 - Manufacturing method of wire rod for soft anneal omitted cold press - Google Patents
Manufacturing method of wire rod for soft anneal omitted cold press Download PDFInfo
- Publication number
- KR100355019B1 KR100355019B1 KR1019980039734A KR19980039734A KR100355019B1 KR 100355019 B1 KR100355019 B1 KR 100355019B1 KR 1019980039734 A KR1019980039734 A KR 1019980039734A KR 19980039734 A KR19980039734 A KR 19980039734A KR 100355019 B1 KR100355019 B1 KR 100355019B1
- Authority
- KR
- South Korea
- Prior art keywords
- rolling
- temperature
- less
- cooling
- wire
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 238000005096 rolling process Methods 0.000 claims abstract description 43
- 238000001816 cooling Methods 0.000 claims abstract description 33
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 32
- 239000010959 steel Substances 0.000 claims abstract description 32
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 238000010583 slow cooling Methods 0.000 claims abstract description 20
- 238000010791 quenching Methods 0.000 claims abstract description 10
- 230000000171 quenching effect Effects 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 6
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 6
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 5
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 12
- 238000000137 annealing Methods 0.000 claims description 5
- 238000003825 pressing Methods 0.000 claims description 2
- 238000005097 cold rolling Methods 0.000 claims 1
- 229910052719 titanium Inorganic materials 0.000 abstract description 6
- 230000009466 transformation Effects 0.000 description 18
- 229910001566 austenite Inorganic materials 0.000 description 17
- 239000000463 material Substances 0.000 description 13
- 229910000859 α-Fe Inorganic materials 0.000 description 12
- 229910001562 pearlite Inorganic materials 0.000 description 10
- 230000002829 reductive effect Effects 0.000 description 7
- 229910000851 Alloy steel Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- 210000001519 tissue Anatomy 0.000 description 6
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910001563 bainite Inorganic materials 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000003303 reheating Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 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
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 210000004872 soft tissue Anatomy 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910001339 C alloy Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 238000010622 cold drawing Methods 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 230000029052 metamorphosis Effects 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/16—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2261/00—Product parameters
- B21B2261/20—Temperature
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
본 발명은 연화소둔 생략형 냉간압조용 선재의 제조방법에 관한 것으로서, 중량 % 로 C: 0.2∼0.5%, Si: 0.1∼0.5%, Mn: 0.2∼1.0%, P: 0.03% 이하, S: 0.03%이하, Cr: 0.6∼1.5%, Mo: 0.1∼0.5%, Ti: 0.005∼0.05%, N: 0.001∼0.020%를 함유하고, 잔부 Fe 및 기타 불가피하게 함유되는 불순물로 조성되는 강편을 1100℃이하의 온도로 가열하는 가열단계와, 마무리 압연온도를 1000℃이하로 하여 열간 선재압연시키는 압연단계와, 압연이 끝난 후 곧바로 730∼780℃까지 급냉시키는 급냉단계와, 이후 0.2∼0.5℃/sec의 냉각속도로 서냉시키는 서냉단계와로 이루어진 연화소둔 생략형 냉간압조용 선재의 제조방법을 제공하는 것을 요지로 한다.The present invention relates to a method for producing a soft annealed cold-rolled wire rod, in weight% C: 0.2 to 0.5%, Si: 0.1 to 0.5%, Mn: 0.2 to 1.0%, P: 0.03% or less, S: 1100 steel sheet containing 0.03% or less, Cr: 0.6-1.5%, Mo: 0.1-0.5%, Ti: 0.005-0.05%, N: 0.001-0.020%, and consisting of remainder Fe and other unavoidable impurities. A heating step of heating to a temperature of less than or equal to ℃, a rolling step of hot wire rolling with a finishing rolling temperature of less than or equal to 1000 ° C, a quenching step of rapidly cooling to 730 to 780 ° C immediately after the rolling is finished, and then 0.2 to 0.5 ° C / Summary of the Invention It is an object of the present invention to provide a method for producing a soft annealed abbreviated cold press wire which consists of a slow cooling step of slow cooling at a cooling rate of sec.
Description
본 발명은 연화소둔 생략형 냉간압조용 선재의 제조방법에 관한 것으로서, 특히 강재를 냉간압조가공하여 기계부품의 체결용 볼트, 너트를 만드는데 사용하는 연화소둔 생략형 냉간압조용 선재의 제조방법에 관한 것이다.The present invention relates to a method for manufacturing a soft annealed abbreviated cold press wire, and more particularly, to a method for manufacturing a soft annealed abbreviated cold press wire used for making bolts and nuts for fastening steel parts. will be.
일반적으로 자동차, 산업기계등의 부품 체결용으로 사용되는 고강도 볼트, 너트는 표 1에 나타낸 바와같이 성분의 중탄소 합금강 선재인 SCM435를 소재로 사용하며 제조공정은 선재를 연화소둔→ 신선→ 구상화열처리→냉간압조를 통하여 제품이 완성된다.In general, high-strength bolts and nuts used for fastening parts of automobiles, industrial machines, etc. are made of SCM435, a medium-carbon alloy steel wire of composition, as shown in Table 1, and the manufacturing process is soft annealing → drawing → spheroidizing heat treatment. → The product is completed through cold press.
이와같은 강은 선재로 열간 압연한 상태에서 인장강도가 약 100∼120kg/mm2정도인데 이러한 고강도강을 냉간에서 직접 신선가공하기가 곤란하기 때문에 통상 연화열처리를 실시하여 선재를 연화시킨 다음 냉간에서 신선가공을 하게 된다.Such steel has a tensile strength of about 100 to 120 kg / mm 2 in the state of hot rolling of wire rod, and since such high strength steel is difficult to be drawn directly from cold, it is usually softened by heat treatment to soften the wire. Fresh processing is done.
연화열처리는 통상 Ac1 변태온도 이하(약 650℃)에서 일정시간 유지한 후 서냉한다. 이와같은 열처리를 실시하면 선재의 경도가 250(Hv)이하로 낮아지게 된다. 연화열처리를 통하여 소재가 연화되는 이유는 전위밀도가 크게 감소하고 또 베이나이트 조직으로부터 시멘타이트의 석출 및 성장이 이루어지기 때문이다. 연화처리된 소재는 냉간신선 공정으로 옮겨져 약 20% 내외로 신선된다. 신선후에는 다시 소재를 750℃전도로 가열하여 약 20시간 정도 구상화열처리를 하여 신선재를 충분히 재연화시킨 다음 냉간압조 공정에 투입하여 볼트 너트를 제작한다.Softening heat treatment is usually slow cooling after maintaining a certain time below Ac1 transformation temperature (about 650 degreeC). When the heat treatment is performed, the hardness of the wire is lowered below 250 (Hv). The reason why the material is softened by the softening heat treatment is that the dislocation density is greatly reduced and the cementite is precipitated and grown from the bainite structure. The softened material is transferred to the cold drawing process and drawn to around 20%. After drawing, the material is again heated to 750 ℃, and spheroidized heat treatment is performed for about 20 hours to fully re-soften the drawn material, and then put into a cold press process to manufacture a bolt nut.
이와같은 공정을 통하여 제품화되는 종래 선재의 경우, 앞에서 언급한 바와같이 선재상태에서의 강도가 너무 높아서 신선가공전에 연화소둔을 해주어야 하기 때문에 제조공정이 길고 제조원가가 높다는 문제점이 있다.In the case of the conventional wire rod manufactured through such a process, as mentioned above, the strength in the wire rod state is too high, so that softening annealing is required before the wire drawing, and thus, the manufacturing process is long and the manufacturing cost is high.
이와같은 문제점을 해결하기 위해서 개발된 것이 연화소둔 생략강으로서 일본 스미토모금속(主友金屬)에서 1984년 개발한 강은 기존의 SCM435강을 선재압연시, 가열온도를 종래의 1200℃에서 950∼1000℃로 낮추고, 마무리 압연온도도 1100℃에서 810∼830℃까지 낮추어 줌으로서 오스테나이트를 미세화시켜 베이나이트 변태를 억제시킴으로서 인장강도 70kg/mm2수준의 연화열처리가 불필요한 냉간압조용 합금강 선재이다. 또 다른 기술로 알려진 것은 일본 가와사끼 제철에서 개발한 것으로, 일본 스미토모금속에서 개발한 강과 유사하게 마무리 압연온도를 900℃이하로 낮추어 줌으로서 인장강도 71kg/mm2수준을 나타내는 냉간압조용 합금강 선재이다.The steel developed in 1984 by Sumitomo Metals, Japan, was developed to solve this problem. The steel was developed in 1984 by Sumitomo Metal, Japan. It is a cold rolled alloy steel wire which does not require softening heat treatment with a tensile strength of 70 kg / mm 2 by lowering the temperature to 1 ° C. and lowering the finish rolling temperature from 1100 ° C. to 810 to 830 ° C. to reduce the bainite transformation by miniaturizing austenite. Another known technique is developed by Japan's Kawasaki Steel, a cold-rolled alloy steel wire that exhibits a tensile strength of 71 kg / mm 2 by lowering the finish rolling temperature below 900 ° C, similar to the steel developed by Sumitomo Metals, Japan.
그러나 상기 강들의 경우는 모두 마무리 압연온도를 900℃이하로 대폭 낮추어 주어야 연질의 합금강 선재를 제조할 수 있다. 강선재를 낮은 온도에서 압연하는 경우에는 압연기에 부하가 많이 걸리기 때문에 압연기 능력이 기존의 압연기 대비 커야 한다. 따라서 이와같은 저온압연을 실시하기 위해서는 기존의 압연기 능력을 대폭 증강시켜 주어야 한다는 문제점이 있다. 또한 선재압연 공장에서 마무리 압연온도를 낮추기 위해서는 압연라인 중간에 강력한 수냉각설비를 설치하여 소재온도를 낮추어 주던가 아니면 압연속도를 크게 감속시켜서 충분한 시간동안 냉각이 되도록 하여야 한다. 그러나 수냉각 설비를 설치하려면 압연라인중간에 충분한 공간이 있어야하고, 또 상당한 설비 투자비가 요구된다. 또한 수냉각 설비없이 압연속도를 감속시켜 온도를 낮추는 경우, 압연속도 감소에 비례하여 생산성이 감소되는 문제점이 있다. 따라서 상기 공지된 기술들에는 추가설비 도입 혹은 설비능력 증강 및 생산성 감소라는 문제점이 있다.However, all of the above steels can be manufactured to a soft alloy steel wire by significantly lowering the finish rolling temperature to 900 ° C or less. When rolling steel wire at low temperature, the load of the rolling mill is high, so the rolling mill capacity should be larger than the conventional rolling mill. Therefore, in order to perform such low-temperature rolling, there is a problem in that the existing rolling mill capability must be greatly enhanced. In addition, in order to lower the finishing rolling temperature in the wire rolling mill, a strong water cooling system should be installed in the middle of the rolling line to lower the temperature of the material or to reduce the rolling speed significantly to allow cooling for a sufficient time. However, the installation of water cooling equipment requires sufficient space in the middle of the rolling line, and requires considerable equipment investment costs. In addition, when the temperature is reduced by reducing the rolling speed without water cooling equipment, there is a problem that productivity is reduced in proportion to the reduction of the rolling speed. Therefore, the known technologies have problems such as introducing additional facilities or increasing facility capacity and decreasing productivity.
따라서 이러한 문제점들을 해결하기 위해 1997년 "연질 냉각압조용 합금강선재의 제조방법(대한민국 특허 출원번호 1997∼23110)"이 개발되었다. 이 발명의 경우는 상기의 예와 같이 심하게 낮은 온도로 저온압연은 해 주지 않아도 되나, 2 톤 단중으로 생산되는 하나의 선재코일에서 급냉부인 선단부와 후단부는 여전히 저온조직으로 변태되어 이 부분을 절단 제거해주어야 한다. 또한 현장 작업시 권취 불량이 발생하여서 선재 링 한두개가 코일 밖으로 돌출되어 나오는 경우, 이부분도 급냉되기 때문에 신선중에 이부분을 제거해주지 않으면 안되는 문제점이 발생한다.Accordingly, in order to solve these problems, "a method of manufacturing an alloy steel wire for soft cold pressing (Korean Patent Application No. 1997-23110)" was developed in 1997. In the case of this invention, it is not necessary to cold-roll at a very low temperature as in the above example, but in one wire coil produced in 2 ton stages, the leading end and the rear end of the quenching part are still transformed into the low temperature tissue, thus cutting off this part. You should. In addition, when one or two wire rods protrude out of the coil due to a winding failure in the field work, this part is also quenched, which causes a problem that this part must be removed during the drawing.
본 발명은 상술한 문제점을 해결하기 위한 것으로서, 선재 압연상태에서 코일 전장에 걸쳐 재질을 충분히 연화시켜 후공정에서 연화열처리가 필요없는 냉간압조강 합금강선재의 제조방법을 제공하는데 그 목적이 있다.An object of the present invention is to provide a method for manufacturing a cold-rolled steel alloy steel wire material that does not require softening heat treatment in a later step by sufficiently softening the material over the entire length of the coil in the wire rolling state.
상술한 목적을 달성하기 위한 본 발명은 중량 % 로 C: 0.2∼0.5%, Si: 0.1∼0.5%, Mn: 0.2∼1.0%, P: 0.03% 이하, S: 0.03%이하, Cr: 0.6∼1.5%, Mo: 0.1∼0.5%, Ti: 0.005∼0.05%, N: 0.001∼0.020%를 함유하고, 잔부 Fe 및 기타 불가피하게 함유되는 불순물로 조성되는 강편을 1100℃이하의 온도로 가열하는 가열단계와, 마무리 압연온도를 1000℃이하로 하여 열간 선재압연시키는 압연단계와, 압연이 끝난 후 곧바로 730∼780℃까지 급냉시키는 급냉단계와, 이후 0.2∼0.5℃/sec의 냉각속도로 서냉시키는 서냉단계로 이루어진 것을 특징으로 한다.The present invention for achieving the above object is by weight% C: 0.2 to 0.5%, Si: 0.1 to 0.5%, Mn: 0.2 to 1.0%, P: 0.03% or less, S: 0.03% or less, Cr: 0.6 to 1.5%, Mo: 0.1% to 0.5%, Ti: 0.005% to 0.05%, N: 0.001% to 0.020%, and heating the steel pieces composed of the remaining Fe and other unavoidable impurities to a temperature of 1100 ° C or lower. A rolling step of hot wire rolling with a finish rolling temperature of 1000 ° C. or lower, a quenching step of quenching immediately to 730 to 780 ° C. immediately after the rolling is finished, and a slow cooling step of slow cooling at a cooling rate of 0.2 to 0.5 ° C./sec. Characterized in consisting of steps.
이하, 본 발명에 대하여 상세히 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.
본 발명은 선재코일 전부분에 걸쳐 균일하게 연화가 이루어져서, 통상 신선가공전에 행하던 연화열처리 생략이 가능한 냉간압조용 합금강 선재를 제조하기 위한 것으로서, 중량 % 로 C: 0.2∼0.5%, Si: 0.1∼0.5%, Mn: 0.2∼1.0%, P: 0.03% 이하, S: 0.03%이하, Cr: 0.6∼1.5%, Mo: 0.1∼0.5%, Ti: 0.005∼0.05%, N: 0.001∼0.020%를 함유하고,잔부 Fe 및 기타 불가피하게 함유되는 불순물로 조성되는 강편을 1100℃이하의 온도로 가열한 후 열간 선재압연을 실시함에 있어 마무리 압연온도를 1000℃이하로 하고, 압연이 끝난 소재는 곧 바로 730∼780℃까지 급냉한 후, 서냉설비를 활용하여 0.2∼0.5℃/sec의 냉각속도로 5∼10분간 서냉시켜야 한다.The present invention is for producing a cold-rolled alloy steel wire that can be softened uniformly over the entire wire coil and can be omitted for softening heat treatment, which is usually done before drawing. C: 0.2 to 0.5% by weight, Si: 0.1 to 0.5%, Mn: 0.2-1.0%, P: 0.03% or less, S: 0.03% or less, Cr: 0.6-1.5%, Mo: 0.1-0.5%, Ti: 0.005-0.05%, N: 0.001-0.020% When the steel strips containing the remaining Fe and other inevitably contained impurities are heated to a temperature of 1100 ° C. or lower and hot wire rolling is carried out, the finish rolling temperature is 1000 ° C. or lower, and the finished material is immediately After quenching to 730-780 ° C, slow cooling is required for 5-10 minutes at a cooling rate of 0.2-0.5 ° C / sec.
이하, 본발명에 있어서 첨가원소의 성분 범위 및 선재 제조조건을 한정하는 이유에 대하여 상세히 설명한다.Hereinafter, the reason for limiting the component range of the additional element and the conditions for producing the wire rod in the present invention will be described in detail.
탄소는 첨가량이 너무 적으면 최종 제품에서 요구하는 강도를 얻을 수 없고 첨가량이 많으면 소입소려 처리후에 강도가 필요이상으로 높아지게 되므로 첨가 범위를 0.2∼0.5%로 제한하는 것이 바람직하다.If the amount of carbon is too small, the strength required for the final product cannot be obtained. If the amount of carbon is too large, the strength is more than necessary after the quenching treatment. Therefore, the addition range is preferably limited to 0.2 to 0.5%.
규소는 탈산 및 필요강도 확보를 위해 첨가한다. 첨가량이 적으면 이러한 효과를 나타내지 못하고, 첨가량이 지나치게 많으면 탈탄을 조장하여 표면경도 및 피로성질을 감소시킨다. 따라서 첨가범위를 0.1∼0.5%로 제한하는 것이 바람직하다.Silicon is added to deoxidize and secure the required strength. If the amount added is small, such an effect is not exhibited. If the amount is added too much, decarburization is promoted to reduce surface hardness and fatigue properties. Therefore, it is preferable to limit the addition range to 0.1 to 0.5%.
망간은 강의 탈산에 필요한 원소이며, 또한 소입성을 개선시킬 목적으로 첨가한다. 첨가량이 많으면 선재 중심부에 편석되어 경질조직인 마르텐사이트(Martensite)를 형성시켜 선재를 경하게 만들어준다. 따라서 첨가범위를 0.2∼1.0%로 제한하는 것이 바람직하다.Manganese is an element necessary for deoxidation of steel and is added for the purpose of improving hardenability. If the addition amount is large, the wire rod is segregated in the center of the wire rod to form a hard structure martensite (Martensite) to make the wire rod hard. Therefore, it is preferable to limit the addition range to 0.2 to 1.0%.
인은 선재중심부에 망간과 함께 편석되어 저온조직을 발생시키고, 소입소려시 균열발생을 조장하는 원소이므로 0.03%이상 첨가되지 않도록 하여야 한다.Phosphorus segregates with manganese in the center of the wire to generate low-temperature tissues, and should not be added more than 0.03% because it is an element that promotes cracking when quenched.
황은 강중에서 입계에 편석되어 인성을 크게 감소시킨다. 따라서 황은 0.03%이상 첨가되지 않도록 하여야 한다.Sulfur segregates at grain boundaries in steel, greatly reducing toughness. Therefore, sulfur should not be added more than 0.03%.
크롬은 열처리시 소입성 확보를 위하여 첨가한다. 첨가량이 적으면 소입성이 떨어지고 첨가량이 많은 경우 소입처리시 균열발생이 쉽고 또 강도가 과도하게 증가하므로 첨가량은 0.6∼1.5%로 제한하는 것이 바람직하다.Chromium is added to ensure quenchability during heat treatment. If the amount is small, the hardenability is low. If the amount is large, cracking is easy during the hardening treatment, and the strength is excessively increased. Therefore, the amount is preferably limited to 0.6 to 1.5%.
몰리브덴은 열처리시 소입성 확보 및 고온강도를 향상시키기 위하여 첨가한다. 첨가량이 적으면 이러한 효과를 얻을 수 없고, 첨가량이 많은 경우 소입처리시 균열발생이 쉽고 또 필요이상으로 강도가 증가하게 되므로 첨가량을 0.1∼0.5%로 제한하는 것이 바람직하다.Molybdenum is added to secure hardenability during heat treatment and to improve high temperature strength. If the addition amount is small, such an effect cannot be obtained. If the addition amount is large, cracking is easily generated during the hardening treatment, and the strength is increased more than necessary. Therefore, the addition amount is preferably limited to 0.1 to 0.5%.
티타늄은 강중에서 질소와 결합하여 티탄질화물(TIN)을 형성한다. 이 질화물은 고온에서 극히 안정하며, 또 오스테나이트 입계에 주로 존재하며 오스테나이트 입자의 성장을 억제시켜 조직을 미세화시키는 역할을 한다. 오스테나이트 조직이 미세하여지면 냉각시 연질조직인 페라이트와 펄라이트의 변태가 촉진되어 선재가 연화된다. 첨가량이 적으면 이러한 효과를 나타낼 수 없고, 첨가량이 많으면 조대한 티탄질화물이 과도하게 석출되어 인성을 감소시키므로 첨가량을 0.005∼0.05%로 한정하는 것이 바람직하다.Titanium combines with nitrogen in steel to form titanium nitride (TIN). This nitride is extremely stable at high temperatures and is mainly present in the austenite grain boundary, and serves to refine the tissue by inhibiting the growth of the austenite particles. If the austenite structure becomes finer, the transformation of the soft and ferrites, such as ferrite and pearlite, is accelerated during cooling, thereby softening the wire rod. If the addition amount is small, such an effect cannot be exhibited. If the addition amount is large, coarse titanium nitride is excessively precipitated to reduce toughness, so the addition amount is preferably limited to 0.005 to 0.05%.
질소는 앞에서 언급한 바와 같이 티타늄과 결합하여 질화물을 형성하여 오스테나이트를 미세화시키는 역할을 한다. 첨가량이 0.001%이하이면 효과가 적고, 0.02% 이상이면 조대한 티탄질화물이 과도하게 생성되어 오히려 강의 인성을 감소키시므로 첨가량을 0.001∼0.02%로 한정한다.As mentioned earlier, nitrogen combines with titanium to form nitrides, which serves to refine austenite. If the added amount is less than 0.001%, the effect is small. If the added amount is less than 0.02%, coarse titanium nitride is excessively produced and the toughness of steel is reduced. Therefore, the added amount is limited to 0.001 to 0.02%.
상기와 같은 조성의 강을 강편으로 제조한 후 1100℃ 이하로 재가열하여 선재압연을 실시한다. 재가열온도가 1100℃이상이 되면, 비록 강중에 티탄질화물이 존재한다 하더라도 오스테나이트 입자의 성장이 완벽하게 억제되지 않아 오스테나이트가 조대하여질 수 있다. 재가열과정에서 오스테나이트 입자가 조대하게 되면 압연을 완료한 상태에서도 오스테나이트 입자가 조대해질 수 있으며, 이렇게 되는 경우 강의 소입성이 증가하여 냉각과정에서 저온조직이 다량 발생되므로 선재를 연화시킬 수 없게 된다. 따라서 가열온도를 1100℃이하로 하여 오스테나이트 성장을 적극 억제시키는 것이 바람직하다.After the steel of the composition described above is manufactured into steel pieces, reheated to 1100 ° C. or less, and the wire is rolled. When the reheating temperature is higher than 1100 ° C., even though titanium nitride is present in the steel, the growth of austenite particles is not completely inhibited, and thus austenite may be coarse. If the austenite grains are coarse during reheating, the austenite grains may be coarsened even after the rolling is completed.In this case, the hardenability of the steel is increased, so that a large amount of low-temperature structure is generated during the cooling process, so that the wire cannot be softened. . Therefore, it is preferable to suppress austenite growth actively by heating temperature below 1100 degreeC.
재가열한 강편은 압연기를 이용하여 필요 선경으로 압연하는데 이때 마무리 압연온도를 1000℃ 이하로 하여야 한다. 공지 기술에서는 마무리 압연온도를 900℃ 이하로 제한하고 있지만 본 발명에서는 이보다 높은 1000℃이상이 되면 오스테나이트가 조대화되어 냉각과정에서 저온변태조직의 발생이 용이하게 된다. 그러나 마무리 온도가 1000℃이하가 되면 티탄질화물이 오스테나이트 입자 성장을 적극 억제하기 때문에 미세한 오스테나이트 입자를 확보할 수 있다.The reheated steel strip is rolled to the required wire diameter by using a rolling mill. At this time, the finish rolling temperature should be below 1000 ℃. In the known technology, the finish rolling temperature is limited to 900 ° C. or lower, but in the present invention, when the temperature reaches 1000 ° C. or higher, the austenite is coarsened, so that the low temperature transformation structure is easily generated during the cooling process. However, when the finishing temperature is 1000 ° C. or lower, since titanium nitride actively suppresses austenite grain growth, fine austenite particles can be secured.
상기와 같은 조건으로 열간 압연한 강재는 압연이 끝나자 말자 곧 바로 730∼770℃까지 급냉한 후, 소재의 현열을 이용하거나 혹은 적당한 서냉설비를 활용하여 0.2∼0.5℃/sec의 냉각속도로 5∼10 분간 서냉시킨 후 강제공냉이나 자연방냉시킨다. 급냉온도가 730℃이하가 되면 이후 뒤따르는 서냉과정에서 페라이트 변태 노즈(nose)를 통과하기가 어려워져 조온조직 생성을 방지하기가 곤란하다. 만일 급냉온도가 780℃ 이상이 되면 오스테나이트 조직의 변태구동력이 그다지 크지 않기 때문에 변태시간이 길어져서 5분 내지 10분간 정도의 단시간의 서냉각을 통해 연질조직을 얻기가 곤란해진다. 목표온도로 급냉한 소재를 0.2℃/sec 보다 더 느린 냉각속도로 서냉하면 연질조직을 얻을 수는 있으나 변태에 걸리는 시간이 너무 길어져 생산성이 크게 떨어진다. 냉각속도를 0.5℃/sec보다 빠르게 하면 오스테나이트가 페라이트+ 펄라이트로 완전히 변태되지 못하고 일부는 저온변태조직인 베이나이트로 변태된다. 서냉시간을 한정하는 이유를 설명하면 5분보다 짧게 서냉시키면 페라이트 + 펄라이트 변태가 완료되지 않은 상태에서 서냉을 종료하게 되어 미변태 오스테나이트가 경질의 베이나이트로 변태하게 되고, 10분이상 서냉시키면 페라이트+ 펄라이트 변태가 완료된 이후에도 불필요하게 계속 서냉을 시키는 셈이되어 생산성을 감소시키는 결과를 조래하게 된다.The steel rolled hot under the above conditions is quenched to 730 ~ 770 ℃ as soon as rolling is finished, and then 5 ~ 5 ~ 2 at a cooling rate of 0.2 ~ 0.5 ℃ / sec by using sensible heat of the material or using a suitable slow cooling equipment. Slow cooling for 10 minutes, then forced air cooling or natural cooling. When the quenching temperature is less than 730 ℃ it is difficult to pass through the ferrite transformation nose (nose) in the subsequent slow cooling process it is difficult to prevent the formation of the temperature control tissue. If the quenching temperature is more than 780 ℃ because the transformation driving force of the austenite tissue is not very large, the transformation time is long, it is difficult to obtain a soft tissue through a short time slow cooling of about 5 to 10 minutes. Slow cooling of the material quenched to the target temperature at a slower cooling rate than 0.2 ° C./sec yields soft tissue, but the time taken for metamorphosis is too long. If the cooling rate is faster than 0.5 ° C / sec, austenite is not completely transformed into ferrite + pearlite and some of it is transformed into bainite, a low temperature transformation tissue. The reason for limiting the slow cooling time is that if the slow cooling is less than 5 minutes, the slow cooling ends when the ferrite + pearlite transformation is not completed, and the untransformed austenite is transformed into hard bainite. + After the perlite transformation is completed unnecessarily slow cooling is to reduce the productivity.
지금까지 언급한 바대로 강종성분, 압연조건 및 냉각조건을 변경하면 극저온 압연을 하지 않을 뿐 아니라 2 톤 중량의 선재 코일의 선, 후단부등의 급냉부를 제거하지 않고도 연화열처리 없이 냉간신선이 가능한 중탄소 저합금강을 제조할 수 있다.As mentioned above, changing the steel grade composition, rolling conditions and cooling conditions not only does not cryogenic rolling but also cold carbon without softening heat treatment without removing quenching parts such as wires and rear ends of 2 ton weight wire coils. Low alloy steels can be produced.
이하 실시예를 통하여 본 발명을 보다 구체적으로 설명한다.The present invention will be described in more detail with reference to the following Examples.
(실시예)(Example)
하기의 표 2와 같은 조성를 갖는 발명강과 비교강종을 소형강괴(160mm ×160mm ×250mm)로 제작한 후 1200 ℃에서 2시간 가열 후 열간에서 압연하여 두께 32mm 판을 제작하였다.Inventive steel and comparative steel grades having the composition as shown in Table 2 below were produced as small ingots (160mm × 160mm × 250mm), heated at 1200 ° C. for 2 hours, and then rolled hot to prepare 32 mm thick plates.
이후 이 열연강판을 시편으로 사용하여 선재압연 및 냉각을 모사실험하였다. 선재압연 종료시와 유사한 크기의 오스테나이트를 얻기위하여 시편은 950℃로 가열후 그 온도에서 5초 동안 유지한 후 30℃/초의 속도로 750℃ 까지 급냉시킨 후 인 온도에서 상온까지 다양한 냉각속도로 냉각하면서 변태온도 및 변태시간을 측정하였으며, 변태완료된 시편에서 미세조직을 관찰하고 경도를 측정하였다. 하기의 표 3은 냉각속도별 페라이트+ 펄라이트 변태완료 온도, 페라이트+ 펄라이트 변태시간, 최종상태에서의 페라이트+펄라이트 분율을 정리하였다. 표 3에서 보면 연질조직을 얻을수 있는 냉각속도 범위는 페라이트+펄라이트 분율을 고려시 0.1∼0.5℃/sec범위임을 알 수 있다. 그러나 냉각속도가 0.1℃/sec인 경우, 변태완료시까지 소요되는 시간이 약 15분 정도이므로 생산성이 저하가 심하다. 냉각속도가 0.2℃/sec로 증가하면 변태소요시간이 8분으로 단축되며, 0.5℃/sec까지 증가하면 약 4분정도로 단축된다. 따라서 생산성에 큰 영향을 주지 않으면서 연질조직을 얻을수 있는 서냉조건은 0.2∼0.5℃/sec라 할 수 있다.After this, the hot rolled steel sheet was used as a specimen to simulate the wire rolling and cooling. In order to obtain austenite of the same size as the end of wire rolling, the specimen was heated to 950 ° C, maintained at that temperature for 5 seconds, then quenched to 750 ° C at a rate of 30 ° C / sec, and then cooled at various cooling rates from phosphorus temperature to room temperature. The transformation temperature and transformation time were measured, and microstructures were observed from the transformed specimens and the hardness was measured. Table 3 below summarizes the ferrite + pearlite transformation temperature, the ferrite + pearlite transformation time, the ferrite + pearlite fraction in the final state by cooling rate. In Table 3, it can be seen that the cooling rate range from which the soft structure can be obtained is 0.1 to 0.5 ° C / sec in consideration of the ferrite + pearlite fraction. However, if the cooling rate is 0.1 ℃ / sec, since the time required to complete the transformation is about 15 minutes, productivity is severely reduced. If the cooling rate is increased to 0.2 ℃ / sec, the transformation time is reduced to 8 minutes, and if the increase to 0.5 ℃ / sec is reduced to about 4 minutes. Therefore, the slow cooling condition to obtain a soft structure without significantly affecting the productivity can be said to 0.2 ~ 0.5 ℃ / sec.
상기의 표 4는 다양한 냉각속도로 냉각시킨 소재의 냉각속도별 경도값 측정결과이다.Table 4 is a result of measuring the hardness value for each cooling rate of the material cooled at various cooling rates.
통상 경도값은 250Hv 이하이면 신선가공전 연화열처리 생략이 가능한 것으로 알려져 있다. 따라서 냉각속도 0.2∼0.5℃/sec 범위이면 연화열처리 생략이 가능함을 알수 있다.It is known that the softening heat treatment can be omitted before drawing, if the hardness value is usually 250 Hv or less. Therefore, it can be seen that the softening heat treatment can be omitted if the cooling rate is in the range of 0.2 to 0.5 ° C / sec.
상술한 바와같이 본 발명은 강중에 티타늄 함량을 적절히 첨가하여 강 조성을 제어하는 한편, 강편 재가열온도, 마무리 압연온도를 제어하고 나아가 서냉설비를 이용하여 압연 후 냉각속도 및 냉각패턴을 적절히 제어하여 선재상태에서 강의 재질을 충분히 연화시킴으로서, 신선전에 실시하는 연화소둔처리를 생략할 수 있다. 연화소둔 생략으로 인한 제조공기 단축효과 및 에너지 절감에 의한 제조원가 절감효과가 있다.As described above, the present invention controls the steel composition by appropriately adding the titanium content in the steel, while controlling the reheating temperature and finish rolling temperature of the slabs, and further, by controlling the cooling rate and the cooling pattern after rolling by using a slow cooling system, the wire state. By sufficiently softening the material of the steel, the soft annealing treatment before drawing can be omitted. There is a shortening effect of manufacturing air due to omission of softening annealing and a manufacturing cost reduction effect by energy saving.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019980039734A KR100355019B1 (en) | 1998-09-24 | 1998-09-24 | Manufacturing method of wire rod for soft anneal omitted cold press |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019980039734A KR100355019B1 (en) | 1998-09-24 | 1998-09-24 | Manufacturing method of wire rod for soft anneal omitted cold press |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20000020918A KR20000020918A (en) | 2000-04-15 |
| KR100355019B1 true KR100355019B1 (en) | 2002-11-18 |
Family
ID=19551826
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1019980039734A KR100355019B1 (en) | 1998-09-24 | 1998-09-24 | Manufacturing method of wire rod for soft anneal omitted cold press |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR100355019B1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100833012B1 (en) * | 2001-12-26 | 2008-05-27 | 주식회사 포스코 | A method for manufacturing a high strength hot-rolled steel sheet for boom preventing camber during working |
| CN115415320B (en) * | 2022-08-31 | 2024-06-11 | 大冶特殊钢有限公司 | Rolling method of 20Cr steel |
-
1998
- 1998-09-24 KR KR1019980039734A patent/KR100355019B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| KR20000020918A (en) | 2000-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4018905B2 (en) | Hot rolled wire rod and bar for machine structure and manufacturing method thereof | |
| MXPA97008775A (en) | Process to produce steel pipe without seams of great strength having excellent resistance to the fissure by tensions by sulf | |
| KR100428581B1 (en) | A non qt steel having superior strength and toughness and a method for manufacturing wire rod by using it | |
| KR20210108002A (en) | A wire rod free from heat treament having high toughness for cold forging and method for manufacturing the same | |
| US4443272A (en) | Process for producing cold rolled steel sheets having excellent press formability and ageing property | |
| KR102209555B1 (en) | Hot rolled and annealed steel sheet having low strength-deviation, formed member, and manufacturing method of therefor | |
| JP2004250768A (en) | Steel for machine structural having excellent cold workability and low decarburizing property, and production method therefor | |
| JP3554506B2 (en) | Manufacturing method of hot-rolled wire and bar for machine structure | |
| KR100355019B1 (en) | Manufacturing method of wire rod for soft anneal omitted cold press | |
| KR100268852B1 (en) | The manufacturing method for cold workability wire rod with excellent spheroidizing heat treatment property | |
| JP2001181791A (en) | Bar stock and wire rod for cold forging, excellent in induction hardenability and cold forgeability | |
| KR100328039B1 (en) | A Method Manufacturing Wire Rods for cold Heading | |
| JPH02213416A (en) | Production of steel bar with high ductility | |
| KR100419046B1 (en) | Method for Manufacturing Martensite Stainless Steel Coil by Batch Annealing Furnace | |
| JPH0112815B2 (en) | ||
| KR100311785B1 (en) | Manufacturing method of alloy wire rod for cold forging | |
| KR100530065B1 (en) | A method for manufacturing steel wire rod for cold forging featuring short-time spheroidized annealing | |
| KR940007275B1 (en) | Making mathod of steel wire rod | |
| KR100431848B1 (en) | Method for manufacturing high carbon wire rod containing high silicon without low temperature structure | |
| KR940007365B1 (en) | Method of manufacturing steel rod | |
| KR100325713B1 (en) | Method for manufacturing alloy steel wire rod and bar | |
| KR100368241B1 (en) | A method for manufacturing hot rolled trip steels with excellent flange formability | |
| KR100276298B1 (en) | The manufacturing method of wire drawing used wire rod contained manganes | |
| JPH026809B2 (en) | ||
| KR100328069B1 (en) | A method of manufacturing wire rods for spring |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E701 | Decision to grant or registration of patent right | ||
| GRNT | Written decision to grant | ||
| FPAY | Annual fee payment |
Payment date: 20120829 Year of fee payment: 11 |
|
| FPAY | Annual fee payment |
Payment date: 20130913 Year of fee payment: 12 |
|
| FPAY | Annual fee payment |
Payment date: 20140916 Year of fee payment: 13 |
|
| FPAY | Annual fee payment |
Payment date: 20150911 Year of fee payment: 14 |
|
| FPAY | Annual fee payment |
Payment date: 20160906 Year of fee payment: 15 |
|
| LAPS | Lapse due to unpaid annual fee |