KR20030052572A - Method for evaluating the degree of annealing of steel sheet - Google Patents

Method for evaluating the degree of annealing of steel sheet Download PDF

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KR20030052572A
KR20030052572A KR1020010082584A KR20010082584A KR20030052572A KR 20030052572 A KR20030052572 A KR 20030052572A KR 1020010082584 A KR1020010082584 A KR 1020010082584A KR 20010082584 A KR20010082584 A KR 20010082584A KR 20030052572 A KR20030052572 A KR 20030052572A
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steel sheet
annealing
magnetic
degree
roll
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김구화
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재단법인 포항산업과학연구원
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Priority to KR1020010082584A priority Critical patent/KR20030052572A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/562—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/20—Metals
    • G01N33/204—Structure thereof, e.g. crystal structure

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  • Mechanical Engineering (AREA)
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Abstract

PURPOSE: A method for measuring an annealing level of a steel sheet is provided to precisely measure the annealing level of the steel sheet in a non-contact manner by comparing signals supplied from two magnetic property measuring devices with each other. CONSTITUTION: A non-magnetic roll(5) is installed at an inlet and an outlet of an annealing furnace(1) in such a manner that a steel sheet(2) passes through the non-magnetic roll(5). Magnetic property measuring devices(3,4) are installed on the non-magnetic roll(5). The magnetic property measuring devices(3,4) include an electromagnet and a magnetic sensor. The non-magnetic roll(5) constantly maintains a distance between the steel sheet(2) and measuring devices(3,4) while preventing the steel sheet(2) from being vibrated. The non-magnetic roll(5) is made of stainless steel.

Description

비접촉식 강판의 소둔 정도 측정방법{METHOD FOR EVALUATING THE DEGREE OF ANNEALING OF STEEL SHEET}METHODS FOR EVALUATING THE DEGREE OF ANNEALING OF STEEL SHEET}

본 발명은 강판의 응력을 제거하기 위한 공정인 소둔 공정에서 강판의 소둔 정도를 비접촉식으로 측정하는 방법에 관한 것이다.The present invention relates to a method for non-contact measurement of the annealing degree of the steel sheet in the annealing step, which is a step for removing the stress of the steel sheet.

강판은 생산 공정에서 압연으로 인한 응력이 많이 잔류해 있게 되므로 그 잔류 응력을 제거하지 않은 상태에서 이를 다음 공정으로 넘길 경우 강판의 반곡과 같은 형상 불량이 발생하는 문제가 있게 된다. 따라서, 압연된 강판은 이를 소둔로에서 열처리하여 응력을 제거하는 과정을 거치게 되는데, 응력제거의 정도를 평가하는 것이 바로 소둔 정도를 평가하는 것이며, 소둔 정도를 측정하는 것은 제품의 품질향상 내지 품질관리의 측면에서 반드시 해야 하는 경우가 많다. 그러나 강종, 두께, 온도 등의 재질적인 문제와 형상 관련 문제, 환경 관련 문제 등의 제약조건이 많이 따르므로 측정목적의 달성이 가능한 장치를 관련설비에 적합하게 설치구비하는 것이 어렵고, 더욱이 하나의 측정장치로 소둔 정도를 정확히 평가하도록 하는 것은 매우 어렵다.Since the steel sheet has a lot of stress due to rolling in the production process, if the residual stress is not removed, the steel sheet may have a shape defect such as bending of the steel sheet. Therefore, the rolled steel sheet undergoes a process of removing the stress by heat-treating it in an annealing furnace, and the evaluation of the degree of stress removal is an evaluation of the degree of annealing. There are many cases that must be done in terms of. However, due to many constraints such as material problems such as steel grade, thickness, and temperature, shape related problems, and environmental related problems, it is difficult to install a device that can achieve the measurement purpose appropriately for the relevant equipment, It is very difficult for the device to accurately assess the extent of annealing.

일반적으로 많이 사용하고 있는 방법은 소둔로의 온도를 측정하여 강종, 두께에 대해 표로 작성된 표준에 따라 평가작업을 한다. 이의 경우는 강판의 소둔 정도를 간접적으로 평가하는 것이므로 실제 강판의 소둔 정도와는 그 오차가 심하다. 따라서 강판의 소둔 정도를 직접 정확히 측정 평가하는 방법의 개발이 필요하며, 특히 생산공정의 방해 없이 소둔 정도를 평가하기 위해서는 비접촉식의 온라인 측정방법이 적합하다.Commonly used methods are to measure the temperature of the annealing furnace and to evaluate the steel grades and thicknesses according to the standard. In this case, since the annealing degree of the steel sheet is indirectly evaluated, the error is severe from the annealing degree of the actual steel sheet. Therefore, it is necessary to develop a method for directly measuring and evaluating the annealing degree of the steel sheet. In particular, a non-contact online measuring method is suitable for evaluating the annealing degree without disturbing the production process.

현재까지 압연 강판의 소둔처리과정에서 진행 강판의 소둔 정도를 온라인으로 측정하는 방법은 보고된 것이 없으며, 단지 위와 같은 간접 측정을 위한 작업표준을 만들기 위하여 여러 가지 소둔 조건에 따라 시편을 채취하여 그 응력을 측정하고 이를 토대로 작업표준 표를 만들어 두는 것이 고작이다.Until now, no method has been reported to measure the annealing degree of the advanced steel sheet during the annealing process of the rolled steel sheet, but the specimens are collected according to various annealing conditions in order to create the working standard for the indirect measurement. It is simply a matter of measuring and setting up a working table.

본 발명은 이러한 배경에서 연구된 것으로, 강판의 소둔 공정에서 소둔로 입구와 출구에 설치한 비자성 롤의 상부에 배치한 두 개의 자성 특성 측정장치로부터취득한 신호를 서로 비교하여 분석함으로써 강판의 소둔 정도를 비접촉식으로 정확히 측정할 수 있는 방법을 제공하는 데 그 목적이 있다.The present invention has been studied in this background, and the annealing degree of the steel sheet by analyzing the signals obtained from the two magnetic properties measuring devices arranged on the top of the non-magnetic roll installed in the inlet and outlet of the annealing furnace in the annealing process of the steel sheet The purpose is to provide a method for accurately measuring non-contacting.

도 1은 강판의 기계적 물성과 자기적 특성에 관계를 나타내는 그림,1 is a diagram showing the relationship between the mechanical properties and magnetic properties of the steel sheet,

도 2는 본 발명의 방법수행을 위한 장치의 구성을 나타낸 도식적인 단면도,Figure 2 is a schematic cross-sectional view showing the configuration of an apparatus for performing the method of the present invention,

도 3은 본 발명에 의한 측정 결과를 나타내는 그래프.3 is a graph showing a measurement result according to the present invention.

* 도면의 주요부분에 대한 부호 설명 *Explanation of symbols on the main parts of the drawings

1 : 소둔로 2 : 강판1: annealing furnace 2: steel sheet

3 : 제1 측정장치 4 : 제2 측정장치3: first measuring device 4: second measuring device

5 : 비자성 롤5: nonmagnetic roll

상기의 목적은 본 발명에 따라 소둔로 입구와 출구에 비자성 롤을 설치하는 단계와, 두 롤의 상부에 전자석과 자기센서로 이루어진 측정 장치를 설치하는 단계와, 상기 두 측정 장치로부터 강판의 자기적 특성을 측정하는 단계와, 두 특성 신호를 취득하는 단계와, 두 신호를 서로 비교하여 자기적 특성의 차이로부터 소둔 정도를 평가하는 단계를 포함하는 비접촉식 강판의 소둔 정도 측정방법을 제공함으로써 달성된다.The above object is to install a non-magnetic roll at the inlet and outlet of the annealing furnace according to the present invention, to install a measuring device consisting of an electromagnet and a magnetic sensor on top of the two rolls, the magnetic of the steel sheet from the two measuring devices It is achieved by providing a method for measuring the annealing degree of a non-contact steel sheet comprising measuring the characteristic characteristics, acquiring two characteristic signals, and comparing the two signals with each other to evaluate the degree of annealing from the difference in magnetic characteristics. .

이하에서, 본 발명을 첨부 도면에 예시된 실시예를 참조하여 더욱 상세히 설명한다.Hereinafter, the present invention will be described in more detail with reference to the embodiments illustrated in the accompanying drawings.

도1은 강판의 기계적 물성과 자기적 특성의 관계를 나타내는 개념을 정리한 그림이다. 동일한 재질의 강판일지라도 응력, 경도, 인장강도, 항복강도 등의 강판의 기계적 성질이 다를 경우 각 강판의 자기적 특성은 차이가 난다. 일례로, 도1과 같이 큰 경도를 지닌 강판의 자기적 물성은 작은 경도를 지닌 강판의 자기적 물성과 큰 차이를 보인다. 이러한 자기적 특성의 차이는 경도에 의해서 뿐만 아니라 응력에 의해서도 동일한 경향성을 나타낸다. 소둔 과정은 강판의 응력뿐만 아니라 경도, 인장강도 등과 같은 기계적 성질에 지대한 영향을 미치므로 강판의 자기적 특성을 측정하면 기계적 특성의 차이를 알 수 있다. 따라서, 동일한 강판에서 소둔 전과 후에 강판의 자기적 특성을 측정하면 소둔 정도를 평가할 수 있는 것이다.1 is a diagram summarizing the concept showing the relationship between mechanical properties and magnetic properties of the steel sheet. Even if steel sheets of the same material have different mechanical properties such as stress, hardness, tensile strength, and yield strength, the magnetic properties of each steel sheet are different. For example, as shown in FIG. 1, the magnetic properties of a steel sheet having a large hardness show a large difference from the magnetic properties of the steel sheet having a small hardness. This difference in magnetic properties shows the same tendency not only by hardness but also by stress. The annealing process greatly affects the mechanical properties such as hardness, tensile strength, as well as the stress of the steel sheet, so the difference in mechanical properties can be seen by measuring the magnetic properties of the steel sheet. Therefore, the degree of annealing can be evaluated by measuring the magnetic properties of the steel sheet before and after annealing in the same steel sheet.

도2는 본 발명의 방법수행을 위한 측정장치의 설치 구성을 나타내는 그림으로, 소둔로(1)의 입구부분과 출구부분에 비자성 롤(5)을 설치하고 그 상부에 강판의 자기적 성질을 측정하는 측정장치(3,4)를 각각 배치하여 강판(2)이 둘 사이로 통판하게 구성한다. 상기 측정장치(3,4)는 전자석과 자기센서로 구성되므로 롤(5)이 자성체로 되어 있을 경우 롤의 자성 특성에 의한 신호가 잡음으로 작용하여 강판의 자성 특성을 측정하는데 방해요소가 된다. 따라서, 상기 롤(5)은 비자성체로 구성된 바, 이 롤(5)은 강판(2)과 측정장치(3,4)와의 거리를 항상 일정하게 유지시키는 기능을 하며, 또 강판의 진동을 방지하는 기능을 한다. 자성 측정장치(3,4)가 직류 전자석을 사용하여 구성될 경우는 비자성 롤(5)이 금속으로 구성되어도 무방하지만, 교류 전자석을 사용하여 구성될 경우는 비자성 롤을 비금속으로 구성하여야 한다.Figure 2 is a diagram showing the installation configuration of the measuring device for performing the method of the present invention, the non-magnetic roll (5) is installed on the inlet and outlet of the annealing furnace (1) and the magnetic properties of the steel plate on the top The measuring apparatuses 3 and 4 to measure are arrange | positioned, respectively, and the steel plate 2 is comprised between two. Since the measuring device (3, 4) is composed of an electromagnet and a magnetic sensor, when the roll (5) is made of a magnetic material, the signal due to the magnetic properties of the roll acts as a noise, which is an obstacle in measuring the magnetic properties of the steel sheet. Therefore, the roll 5 is made of a nonmagnetic material, and the roll 5 functions to maintain a constant distance between the steel sheet 2 and the measuring devices 3 and 4 at all times, and also prevents vibration of the steel sheet. Function. If the magnetic measuring device (3, 4) is configured using a direct current electromagnet, the nonmagnetic roll (5) may be made of metal. However, if the magnetic measuring device (3, 4) is constructed using an alternating electromagnet, the nonmagnetic roll should be made of nonmetal. .

본 발명의 일실시예에 있어서는 상기 측정장치(3,4)의 구성요소로 직류 전자석을 사용하였으므로 비자성 롤(5)을 스테인레스로 제작하였다. 만약, 스테인레스 비자성 롤을 용접하여 제작할 경우는 용접부에서 자기적 성질을 지니게 되므로 반드시 심레스(seamless) 스테인레스를 사용하여 롤을 제작하여야 한다. 심레스 롤을 사용하지 않을 경우 롤에 의한 신호를 제거할 수는 있지만 롤에 의한 신호와 소둔 정도를 나타내는 신호의 주기가 동일할 경우는 둘을 구분하는데 어려움이 있게 된다.In one embodiment of the present invention, since a direct current electromagnet was used as a component of the measuring devices 3 and 4, the nonmagnetic roll 5 was made of stainless steel. If the non-magnetic stainless steel roll is manufactured by welding, it must have a magnetic property at the weld, so the roll must be manufactured using seamless stainless steel. If the seamless roll is not used, the signal caused by the roll can be eliminated, but it is difficult to distinguish the two when the signal caused by the roll and the signal period indicating the annealing degree are the same.

도3은 본 발명에 의해서 소둔 정보를 평가하는 출력신호의 한 예를 나타낸 것이다. 도3의 a는 소둔 전후에 대한 자기센서 신호를 강판의 길이에 대하여 출력한 것이며, b는 위 a를 퓨리어 트랜스폼(FFT)한 결과이다. 도3의 a에서 보는 바와 같이 소둔 전에는 강판의 자기적 성질이 나쁘게 되어 큰 신호가 발생하며, 그 불균일 정도도 심함을 알 수 있다. 이 강판이 소둔로를 거친 후는 점선과 같이 강판의 자기적 성질이 향상되고 불균일 정도도 향상됨을 알 수 있다.3 shows an example of an output signal for evaluating annealing information according to the present invention. 3A outputs a magnetic sensor signal for the length of the steel sheet before and after annealing, and b is a result of Fourier transform (FFT) on a. As shown in Fig. 3a, before the annealing, the magnetic properties of the steel sheet become bad and a large signal is generated, and it can be seen that the degree of unevenness is also severe. After the steel sheet passes through the annealing furnace, it can be seen that the magnetic properties of the steel sheet are improved and the degree of nonuniformity is improved as in the dotted line.

소둔 정도를 안정적으로 평가하기 위하여 도3의 b와 같이 FFT한 결과를 비교하였다. 소둔 전과 후의 신호 주파수는 일치하지만 그 크기가 소둔 후 현격하게 감소함을 알 수 있다. 소둔 전에는 18Hz와 40Hz 근처의 신호 크기가 약 0.15였으나 소둔 후에는 약 0.03 정도로 자기적 특성이 5배 정도 향상됨을 알 수 있고, 이는 소둔이 잘 된 것임을 알 수 있다. 만약 소둔 정도를 합격으로 평가하는 기준을 0.05로 설정할 경우 FFT한 신호의 크기가 소둔 후 0.05를 초과하면 소둔을 다시 해야 함을 결정할 수 있다.In order to stably evaluate the annealing degree, the results of the FFT as in FIG. 3b were compared. It can be seen that the signal frequencies before and after annealing coincide, but the magnitude is significantly reduced after annealing. Before annealing, the signal size around 18Hz and 40Hz was about 0.15, but after annealing, the magnetic properties improved about 5 times by about 0.03, which indicates that the annealing was well done. If the criterion for evaluating the annealing degree to pass is set to 0.05, if the magnitude of the FFT signal exceeds 0.05 after annealing, it may be determined that annealing should be performed again.

본 발명의 방법은 상술한 바와 같은 단계들을 통해 강판의 소둔 정도를 비접촉식으로 정확히 측정 평가할 수 있으므로 제품의 품질 및 생산성을 향상시킬 수 있는 효과를 제공한다.The method of the present invention can accurately measure and evaluate the annealing degree of the steel sheet through the steps as described above, thereby providing an effect of improving the product quality and productivity.

Claims (1)

소둔로 입구와 출구에 강판이 통판되는 비자성 롤(5)을 설치하는 단계와, 상기 두 롤의 상부에 전자석과 자기센서로 이루어진 측정장치(3)(4)를 설치하는 단계와, 상기 두 측정장치에 의해 강판의 소둔 전, 후의 자기적 특성을 측정하는 단계와, 상기 단계에서의 측정 결과로부터 소둔 정도를 평가하는 단계를 포함하는 비접촉식 강판의 소둔 정도 측정방법.Installing a non-magnetic roll (5) through which the steel sheet is passed through the inlet and outlet of the annealing furnace, and installing the measuring device (3) (4) consisting of an electromagnet and a magnetic sensor on top of the two rolls; An annealing degree measuring method of a non-contact steel sheet comprising the steps of measuring the magnetic properties before and after annealing the steel sheet by a measuring device, and evaluating the annealing degree from the measurement results in the step.
KR1020010082584A 2001-12-21 2001-12-21 Method for evaluating the degree of annealing of steel sheet KR20030052572A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210011750A (en) 2019-07-23 2021-02-02 김병일 Assembly type block

Citations (4)

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Publication number Priority date Publication date Assignee Title
US4061508A (en) * 1975-06-06 1977-12-06 Trefimetaux Method for continuously measuring the annealing level on wires or strips
JPH0658907A (en) * 1992-08-10 1994-03-04 Nippon Steel Corp Method for evaluating quality of magnetic material
JPH0933517A (en) * 1995-07-21 1997-02-07 Kawasaki Steel Corp Method for measuring quality of steel plate
JPH11153581A (en) * 1997-11-21 1999-06-08 Kawasaki Steel Corp Method and apparatus for measuring on line progress of recovery-recrystallization of steel plate being annealed and method for continuous annealing of steel plate

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4061508A (en) * 1975-06-06 1977-12-06 Trefimetaux Method for continuously measuring the annealing level on wires or strips
JPH0658907A (en) * 1992-08-10 1994-03-04 Nippon Steel Corp Method for evaluating quality of magnetic material
JPH0933517A (en) * 1995-07-21 1997-02-07 Kawasaki Steel Corp Method for measuring quality of steel plate
JPH11153581A (en) * 1997-11-21 1999-06-08 Kawasaki Steel Corp Method and apparatus for measuring on line progress of recovery-recrystallization of steel plate being annealed and method for continuous annealing of steel plate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210011750A (en) 2019-07-23 2021-02-02 김병일 Assembly type block

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