KR20170075056A - Apparatus and Method for measuring magnetic stress of cold rolled steel - Google Patents

Apparatus and Method for measuring magnetic stress of cold rolled steel Download PDF

Info

Publication number
KR20170075056A
KR20170075056A KR1020150183562A KR20150183562A KR20170075056A KR 20170075056 A KR20170075056 A KR 20170075056A KR 1020150183562 A KR1020150183562 A KR 1020150183562A KR 20150183562 A KR20150183562 A KR 20150183562A KR 20170075056 A KR20170075056 A KR 20170075056A
Authority
KR
South Korea
Prior art keywords
cold
thin plate
coil
magnetic flux
flux density
Prior art date
Application number
KR1020150183562A
Other languages
Korean (ko)
Inventor
배진수
Original Assignee
주식회사 포스코
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 포스코 filed Critical 주식회사 포스코
Priority to KR1020150183562A priority Critical patent/KR20170075056A/en
Publication of KR20170075056A publication Critical patent/KR20170075056A/en

Links

Images

Classifications

    • 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
    • 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
    • G01N27/80—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating mechanical hardness, e.g. by investigating saturation or remanence of ferromagnetic material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

An apparatus for measuring the mechanical strength of a cold-rolled steel sheet according to an embodiment of the present invention includes: a current supplier for providing a sinusoidal current; A first coil for generating a sinusoidal magnetic field using the sinusoidal current to magnetize the cold rolled thin plate in the longitudinal direction; A second coil for detecting a magnetic flux density of the magnetized cold rolled thin plate; And a strength measuring unit for measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage generated by the magnetic flux density.

Figure P1020150183562

Description

Technical Field [0001] The present invention relates to an apparatus and a method for measuring mechanical strength of a cold rolled thin plate,

The present invention relates to an apparatus and a method for measuring the mechanical strength of a cold rolled thin plate.

The mechanical strength of cold rolled steel sheet is one of the core quality conditions of cold rolled steel sheet, including tensile strength and yield strength. However, the final test of mechanical properties is carried out by using one specimen By offline testing, we represent the mechanical properties of the entire coil to customers.

The specimen collection site corresponds to the tip or rear end of the cold rolled thin strip and the deviation of the mechanical properties is much occurred. Since the strength value of this specimen is insufficient to guarantee the mechanical properties of the electric field, .

In addition, there is an increasing demand for minimizing the defective mechanical properties of a product by controlling mechanical properties by feedback of changes in mechanical properties in the process.

Methods for measuring mechanical properties through off-line tensile testing are well known, but this method is a destructive method that can not be applied on-line.

As a technique for measuring mechanical properties on-line, a method of measuring relative magnetic reluctance by applying an impulse magnetic field as shown in Fig. 1 has been commercialized. However, this technique has a problem in that the interval from the cold rolled thin plate to the sensor is small, There are many constraints to be applied on-line in a way that the influence of the measurement value is large and the risk of the sensor is high.

In order to measure the mechanical properties online, it is necessary to obtain a stable measurement value for various shapes and vibrations of the cold rolled sheet, but such measures have not been proposed yet.

Korean Patent Application No. 2009-0083273 (entitled "Incident Inspection Device for Cold Rolled Steel Sheet Using Magnetic Sensor")

An object of the present invention is to provide an apparatus and a method for measuring the mechanical strength of a cold rolled thin plate which can measure the mechanical strength of a cold rolled thin plate by using magnetic properties of a cold rolled thin plate.

An apparatus for measuring the mechanical strength of a cold rolled thin plate according to an embodiment of the present invention includes: a current providing unit for providing a sinusoidal current; A first coil for generating a sinusoidal magnetic field using the sinusoidal current to magnetize the cold rolled thin plate in the longitudinal direction; A second coil for detecting a magnetic flux density of the magnetized cold rolled thin plate; And a strength measuring unit for measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage generated by the magnetic flux density.

A method of measuring the mechanical strength of a cold rolled thin plate according to an embodiment of the present invention includes: a first step of providing a sinusoidal current; A second step of generating a sinusoidal magnetic field by using the sinusoidal current in the first coil to magnetize the cold rolled thin plate in the longitudinal direction; A third step of detecting magnetic flux density of the magnetized cold rolled thin plate by a second coil; And a fourth step of measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage signal obtained by converting the magnetic flux density.

According to the present invention, the cold-rolled thin plate production process is less influenced by the shape and vibration of the cold-rolled thin plate, thereby providing the advantage of being able to have on-site application and maintainability as well as obtaining a stable cold rolled thin plate on-line.

1 is a graph showing a magnetic hysteresis curve.
2 is an apparatus view showing an apparatus for measuring mechanical strength of a cold rolled thin plate according to an embodiment of the present invention.
3 is a flowchart illustrating a method of measuring mechanical strength of a cold rolled thin plate according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

Hereinafter, the cooling will be described in more detail with reference to the drawings, in an embodiment of the present invention.

Hereinafter, an apparatus and method for measuring the mechanical strength of a cold rolled sheet according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is an exemplary view showing an apparatus for measuring the mechanical strength of a cold rolled thin plate according to an embodiment of the present invention.

The apparatus 100 for measuring mechanical properties of a cold-rolled steel sheet shown in FIG. 1 includes a current providing unit 110, a first coil 120, a second coil 130, and a strength measuring unit 140.

The current providing unit 110 performs a function of providing a sinusoidal current, and includes an oscillation unit 111 and a current amplification unit 112. The oscillation unit 111 generates a sinusoidal signal, and the current amplification unit 112 amplifies the sine wave signal to a sinusoidal current.

The first coil 120 is an elliptical magnetization coil and is positioned above the cold rolled thin plate S to generate a sinusoidal magnetic field in the longitudinal direction of the cold rolled thin plate S using the sinusoidal current, Magnetize it.

At this time, the cold-rolled thin plate S generates a magnetic flux Φ in the longitudinal direction, and the magnetic flux Φ can be expressed by the following Equation 1.

[Formula 1]

Figure pat00001

Ni is the magnetic flux, N is the number of turns of the magnetizing coil, H is the intensity of the sinusoidal magnetic field, and 1 is the length of the magnetic field.

On the other hand, the magnetic flux density? Generated in the longitudinal direction of the cold-rolled thin plate S and the magnetic flux density B in the cold-rolled thin plate S have a relationship as shown in the following Equation 2, The relationship between the magnetic flux density (B) and the following expression (3) is established.

[Formula 2]

Figure pat00002

Here, A is the sectional area of the cold rolled thin plate.

[Formula 3]

Figure pat00003

Here, μ = permeability of the medium

In an ideal case, the magnetic flux density is proportional to the intensity of the magnetic field. However, since most media have magnetic saturation phenomena, the magnetic flux density B has a value proportional to the magnetic field intensity H when the magnetic field strength H has a small value, The magnetic flux density (B) is saturated without being proportionally increased since the medium is magnetically saturated.

Therefore, when an AC magnetic field is applied, the medium has a BH relationship curve as shown in FIG. 1 due to its hysteresis characteristic, and this curve is called a magnetic hysteresis curve. Here, the medium refers to a cold rolled thin plate, and the hysteresis characteristic refers to a characteristic of a cold rolled thin plate.

Next, the second coil 130 performs a function of detecting the magnetic flux density of the magnetized cold rolled thin plate.

More specifically, the second coil 130 may be in the form of a solenoid surrounding the lower portion of the magnetized cold rolled thin plate S, and detects the magnetic flux density B by the sinusoidal magnetic field.

The magnetic flux density B detected by the second coil 130 is converted into a voltage signal as shown in Equation 4 below and the converted voltage signal is supplied to the voltage measuring unit 140 (141).

[Formula 4]

Figure pat00004

Here, n is the number of windings of the detection coil, v is a voltage measured by a voltage measuring device, and t is time.

Next, the strength measuring unit 140 measures the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage generated by the magnetic flux density do.

More specifically, the intensity measuring unit 140 may include a voltage measuring unit 141, a first processing unit 142, and a second processing unit 143.

The voltage measuring unit 141 measures a voltage signal generated in the second coil.

The first processing unit 142 performs a function of detecting the coercive force (H c ) of the cold-rolled thin plate on the basis of the sinusoidal current (i) and the voltage signal. At this time, the first processing section 142 detects the coercive force Hc by using the following expression (5).

Here, the coercive force Hc represents the intensity of the magnetic field when the magnetic flux density is 0, from the magnitude of the magnetic field H and the magnitude of the magnetic flux density B.

For reference, the coercive force (Hc) is one of the important magnetic properties of the cold rolled thin plate (S) and correlates with the mechanical properties of the cold rolled thin plate (S). The magnitude of the coercive force H C in the magnetic properties of the cold rolled thin plate S is inversely proportional to the average grain diameter D in the cold rolled thin plate S as shown in the following formula 5 and is the square root of the dislocation density N .

[Formula 5]

Figure pat00005

Here, N is the dislocation density and D is the average particle diameter.

Generally, the mechanical strength of the cold-rolled thin plate S increases as the average particle diameter D in the cold rolled thin plate becomes smaller, and becomes larger as the dislocation density N increases.

The second processing section 143 performs a function of detecting the mechanical strength of the cold-rolled steel sheet on the basis of the coercive force Hc and the tensile test relational expression.

3 is a flowchart illustrating a method of measuring mechanical strength of a cold rolled thin plate according to an embodiment of the present invention.

As shown in FIG. 3, the method S700 of measuring the mechanical strength of a cold rolled thin plate according to an embodiment of the present invention may include a first step (S710) to a fourth step (S740).

The first step S710 may be a step of providing a sinusoidal current and generating a sinusoidal signal in the oscillation unit 111 and amplifying the sinusoidal wave signal into a sinusoidal current in the current amplification unit 112, have.

Next, the second step S720 may be a step of magnetizing the cold rolled thin plate in the longitudinal direction by generating a sinusoidal magnetic field using the sinusoidal current in the first coil.

In the third step S730, the magnetic flux density of the magnetized cold rolled thin plate may be detected by the second coil.

The fourth step S740 may be a step of measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate based on the sinusoidal current and the voltage signal obtained by converting the magnetic flux density.

In the third step S730, the voltage measuring unit may convert the detected magnetic flux density into the voltage signal using Equation 4 described below.

[Formula 4]

Figure pat00006

Here, n is the number of windings of the detection coil, v is a voltage measured by a voltage measuring device, and t is time.

Accordingly, the present invention provides less advantageous effects on the shape and vibration of the cold rolled thin plate in the cold rolled thin plate production process, thereby providing the advantage of being able to provide on-site application and maintenance as well as obtaining a stable cold rolled thin plate on-line .

For reference, "part" of the present invention may be a computing device, and the computing device may include at least one processing unit and memory.

The processing unit may include a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) And may have a plurality of cores.

The memory may be a volatile memory (e.g., RAM, etc.), a non-volatile memory (e.g., ROM, flash memory, etc.), or a combination thereof.

The computing device may also include additional storage. Storage includes, but is not limited to, magnetic storage, optical storage, and the like.

The storage may store computer readable instructions for implementing one or more embodiments disclosed herein, and may also store other computer readable instructions for implementing an operating system, application programs, and the like. The computer readable instructions stored in the storage may be loaded into memory for execution by the processing unit.

On the other hand, a computing device may include communication connection (s) that enable it to communicate with other devices through the network. Here, the communication connection (s) may include a modem, a network interface card (NIC), an integrated network interface, a radio frequency transmitter / receiver, an infrared port, a USB connection or other interface for connecting a computing device to another computing device . The communication connection (s) may also include wired connections or wireless connections.

Each component of the computing device described above may be connected by various interconnects (e.g., peripheral component interconnect (PCI), USB, firmware (IEEE 1394), optical bus architecture, etc.) As shown in FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the present invention is not limited to the disclosed exemplary embodiments, but various changes and modifications may be made without departing from the scope of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but are intended to illustrate and not limit the scope of the technical spirit of the present invention. The scope of protection of the present invention should be construed according to the claims, and all technical ideas which are within the scope of the same should be interpreted as being included in the scope of the present invention.

100: Mechanical strength measuring device for cold-rolled steel sheet
110: Current supply
120: first coil
130: second coil
140:
141: Voltage measuring unit
142: first processing section
143: second processing section

Claims (7)

A current providing unit for providing a sinusoidal current;
A first coil generating a sinusoidal magnetic field using the sinusoidal current to magnetize the cold rolled thin plate;
A second coil for detecting a magnetic flux density of the magnetized cold rolled thin plate; And
And a strength measuring unit for measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage generated by the magnetic flux density.
The method according to claim 1,
Wherein the first coil is an elliptical magnetization coil positioned on the upper portion of the cold-rolled steel plate.
The method according to claim 1,
And the second coil is a solenoid coil located at a lower portion of the cold-rolled steel plate.
The method according to claim 1,
Wherein the intensity measuring unit comprises:
A voltage measuring unit for converting the magnetic flux density detected by the second coil into a voltage signal;
A first processor for detecting the coercive force of the cold rolled thin plate based on the sinusoidal current and the voltage signal; And
And a second processing section for detecting the mechanical strength of the cold-rolled steel sheet on the basis of the coercive force and the tensile test relational expression.
5. The method of claim 4,
The voltage measuring unit includes:
A mechanical strength measuring device for a cold-rolled steel sheet, which converts the detected magnetic flux density into the voltage signal by using Equation (4) described below.
[Formula 4]
Figure pat00007

Here, n is the number of turns of the detection coil, v is the voltage, and t is the time.
A first step of providing a sinusoidal current;
A second step of generating a sinusoidal magnetic field using the sinusoidal current in the first coil to magnetize the cold rolled thin plate;
A third step of detecting magnetic flux density of the magnetized cold rolled thin plate by a second coil;
And a fourth step of measuring the mechanical strength of the cold-rolled steel sheet from the coercive force after detecting the coercive force of the cold-rolled thin plate on the basis of the sinusoidal current and the voltage signal obtained by converting the magnetic flux density .
The method according to claim 6,
In the third step,
And converting the detected magnetic flux density into the voltage signal using a voltage measuring unit using Equation (4) described below.
[Formula 4]
Figure pat00008

Here, n is the number of windings of the detection coil, v is voltage, and t is time.
KR1020150183562A 2015-12-22 2015-12-22 Apparatus and Method for measuring magnetic stress of cold rolled steel KR20170075056A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020150183562A KR20170075056A (en) 2015-12-22 2015-12-22 Apparatus and Method for measuring magnetic stress of cold rolled steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150183562A KR20170075056A (en) 2015-12-22 2015-12-22 Apparatus and Method for measuring magnetic stress of cold rolled steel

Publications (1)

Publication Number Publication Date
KR20170075056A true KR20170075056A (en) 2017-07-03

Family

ID=59358094

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150183562A KR20170075056A (en) 2015-12-22 2015-12-22 Apparatus and Method for measuring magnetic stress of cold rolled steel

Country Status (1)

Country Link
KR (1) KR20170075056A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200017798A (en) 2018-08-09 2020-02-19 주식회사 포스코 Apparatus and method for measuring remanence of steel material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200017798A (en) 2018-08-09 2020-02-19 주식회사 포스코 Apparatus and method for measuring remanence of steel material

Similar Documents

Publication Publication Date Title
CN107064291B (en) Magnetic gathering pulse eddy current coil detection sensor
US10677755B2 (en) Apparatus and method for detecting inner defects of steel plate
CN103499636B (en) Based on the lossless detection method of microdefect in the thin plate class ferromagnetic material of the magnetostatic power of survey
CN205861255U (en) Ferromagnetic material stress based on barkhausen detection device
CN103234449B (en) Reduce electrically conductive film method for measuring thickness and the device of lift-off influence of fluctuations
EP2709271A3 (en) Quiescent current determination using in-package voltage measurements
CN108152763B (en) Measuring device and measuring method for direct-current magnetic shielding efficiency
KR20170120167A (en) Rope damage diagnosis test equipment and rope damage diagnosis test method
CN201051089Y (en) A real time multi-channel whirlpool and magnetic memory/magnetism leakage detection device
CN103728368A (en) Crack detector used for rail parts
KR20170075056A (en) Apparatus and Method for measuring magnetic stress of cold rolled steel
CN102411132A (en) Magnetic stress nondestructive detection system
KR101254300B1 (en) Apparatus for detecting thickness of the conductor using dual core
CN107246928B (en) A kind of pressure sensor and its working method using electromagnetic principle
CN103439405A (en) Multifunctional electromagnetic detection sensor synchronized by iron core and ferrite core and detection method thereof
CN108896459B (en) Magnetic hydrogel magnetic particle concentration detection method based on alternating magnetic field pulse infrared
KR101143054B1 (en) Apparatus and method for measuring the strength of quality of steel plate
CN107063073B (en) Object deformation electromagnetic monitoring device and method
CN103954654A (en) Method for detecting discontinuity of nonmetal material by virtue of inductance of series resonant circuit
JP2012078349A (en) Pulse excitation type inspection device, and pulse excitation type inspection method
CN110907532A (en) Magnetic flux leakage detection method based on compressed sensing
CN205539420U (en) Magnetism barkhausen and magnetism parameter sensor
CN103196994B (en) A kind of assay method exchanging effective range in yoke method magnetic powder inspection
CN103968974B (en) A kind of band coating ferromagnetic metal workpiece non-demolition stress quantitative detecting method
CN104112563B (en) A kind of designing and employing method exchanging Heng Ciyuan

Legal Events

Date Code Title Description
E601 Decision to refuse application